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Principles of Critical Care with increased delirium). An evidence based practice for cor- adequate nutrition and hydration. For further discussion of rection of oversedation is to stop the drug until the level of seda- delirium, see MKSAP 19 Neurologz. tion is appropriate and then restart it at halfthe previous dose. rEY ?OIXTS o Sedation and analgesia should be monitored using Intermption of Sedation and Analgesia Daily protocolized interruption of sedation and analgesia in objective standardized scales.

with increased delirium). An evidence based practice for cor- adequate nutrition and hydration. For further discussion of rection of oversedation is to stop the drug until the level of seda- delirium, see MKSAP 19 Neurologz. tion is appropriate and then restart it at halfthe previous dose. rEY ?OIXTS o Sedation and analgesia should be monitored using Intermption of Sedation and Analgesia Daily protocolized interruption of sedation and analgesia in objective standardized scales. critically ill patients is associated with decreased length of o Benzodiazepines should not be used for treating delirium HVC mechanical ventilation, length of ICU stay, and incidence of unless they are needed to treat alcohol withdrawal or delirium, although possibly no difference in 90 day mortality. seizures. Protocolized light sedation has shown similar patient out comes to daily sedation interruption. Nutritional Support Malnutrition in critically ill patients leads to increased mor- Delirium bidity and mortality. All patients in the ICU should have a Delirium is characterized by an acute change in cognitive func nutritional evaluation. Enteral nutrition should start within 24 tioning over hours to days, with fluctuations during the course to 48 hours of admission. Early enteral nutrition is associated of the day. Features of delirium include inattention, disorgan- with a decrease in mortality and infections. Enteral nutrition ized thinking, executive dysfunction (difficulty with problem is preferred unless a contraindication is present (e.g., perfora solving), altered level ofconsciousness (lethargr or hypervigi- tion, hemorrhage). Patients receiving vasopressors, neuro lance), perceptual disturbances (hallucinations or delusions), muscular blockers, hypothermia, or extracorporeal life altered psychomotor activity (hyperactivity, hlpoactivity, or support should receive enteral nutrition as soon as they can both), sleep wake disturbances, and labile mood. Delirium is tolerate it. Critically ill patients who cannot maintain voli extremely common in ICU patients and is associated with tional nutritional intake should be fed as soon as possible increased length of ICU stay, morbidity, mortality, and post using a gastric tube, large bore tube, small-bore tube, or post intensive care cognitive impairment. Risk factors for delirium pyloric tube. Guidelines recommend postpyloric feeding when include exposure to benzodiazepines, blood transfusion, pre a high risk for aspiration exists, but delays in placing a postpy- existing dementia, older age, previous coma, pre ICU surgery loric tube should not delay initiation of enteral nutrition. or trauma, and high severity of illness on ICU admission. Routine measurement of gastric residuals is not recommended Patients should be monitored and assessed using scales such as because it delays achievement of feeding goals, increases the the Confusion Assessment Method-lCU or Intensive Care risk ofclogging the enteral access, and may increase the risk Delirium Screening Checklist. Measures to decrease delirium for aspiration. include early mobilization, preservation of nocturnal sleep, Guidelines recommend that supplemental parenteral adequate pain management, orientation of the patient, removal nutrition should be considered only after 7 to 10 days of meet ofvascular and urethral catheters, provision ofvisual and hear ing less than 60'l, of energr and protein requirements by the ing aids, and minimization of nonessential medications. Early enteral route alone. Adding parenteral nutrition to supplement mobilization in the earliest days of critical illness can be effec- enteral nutrition before this period may lead to harm and tive for treating and preventing delirium. Large randomized should be avoided. In contrast, parenteral nutrition should be studies have failed to demonstrate the effectiveness of any started as soon as possible for severely malnourished patients, medication to prevent or treat delirium. Use of antipsychotics those at high risk for malnutrition, and those for whom enteral are controversial. with no conclusive evidence of benefit. nutrition is not possible. Benzodiazepines should not be used unless they are needed to TEV POIl{IS treat alcohol withdrawal or seizures. Treatment involves iden- tification and correction of the underlying cause, multicompo . Enteral nutrition is preferred and should be started within nent bundled interventions (Table a ), and maintaining 24to 48 hours of admission to the ICU. o In nonmalnourished patients, supplemental parenteral TABLE 44. ABCDEF Care Bundle for Managing Delirium nutrition should be considered only after 7 to 10 days of in the ICU meeting less than 60% of energr and protein requirements A: Assess, prevent, and manage pain by the enteral route alone. B: Perform Both SATand SBT . In patients receiving enteral feedings, measurement of C: Choice of sedation and analgesia gastric residuals is not recommended because it delays HVC achievement offeeding goals, increases the risk ofclog- D: Delirium: assessment, prevention, and management ging the enteral access, and may increase the risk for E: Early mobility and exercise aspiration. F: Family engagement and empowerment o Administration of parenteral nutrition to supplement HVC enteral nutrition may lead to harm and should be avoided.

critically ill patients is associated with decreased length of o Benzodiazepines should not be used for treating delirium HVC mechanical ventilation, length of ICU stay, and incidence of unless they are needed to treat alcohol withdrawal or delirium, although possibly no difference in 90 day mortality. seizures. Protocolized light sedation has shown similar patient out comes to daily sedation interruption. Nutritional Support Malnutrition in critically ill patients leads to increased mor- Delirium bidity and mortality. All patients in the ICU should have a Delirium is characterized by an acute change in cognitive func nutritional evaluation. Enteral nutrition should start within 24 tioning over hours to days, with fluctuations during the course to 48 hours of admission. Early enteral nutrition is associated of the day. Features of delirium include inattention, disorgan- with a decrease in mortality and infections. Enteral nutrition ized thinking, executive dysfunction (difficulty with problem is preferred unless a contraindication is present (e.g., perfora solving), altered level ofconsciousness (lethargr or hypervigi- tion, hemorrhage). Patients receiving vasopressors, neuro lance), perceptual disturbances (hallucinations or delusions), muscular blockers, hypothermia, or extracorporeal life altered psychomotor activity (hyperactivity, hlpoactivity, or support should receive enteral nutrition as soon as they can both), sleep wake disturbances, and labile mood. Delirium is tolerate it. Critically ill patients who cannot maintain voli extremely common in ICU patients and is associated with tional nutritional intake should be fed as soon as possible increased length of ICU stay, morbidity, mortality, and post using a gastric tube, large bore tube, small-bore tube, or post intensive care cognitive impairment. Risk factors for delirium pyloric tube. Guidelines recommend postpyloric feeding when include exposure to benzodiazepines, blood transfusion, pre a high risk for aspiration exists, but delays in placing a postpy- existing dementia, older age, previous coma, pre ICU surgery loric tube should not delay initiation of enteral nutrition. or trauma, and high severity of illness on ICU admission. Routine measurement of gastric residuals is not recommended Patients should be monitored and assessed using scales such as because it delays achievement of feeding goals, increases the the Confusion Assessment Method-lCU or Intensive Care risk ofclogging the enteral access, and may increase the risk Delirium Screening Checklist. Measures to decrease delirium for aspiration. include early mobilization, preservation of nocturnal sleep, Guidelines recommend that supplemental parenteral adequate pain management, orientation of the patient, removal nutrition should be considered only after 7 to 10 days of meet ofvascular and urethral catheters, provision ofvisual and hear ing less than 60'l, of energr and protein requirements by the ing aids, and minimization of nonessential medications. Early enteral route alone. Adding parenteral nutrition to supplement mobilization in the earliest days of critical illness can be effec- enteral nutrition before this period may lead to harm and tive for treating and preventing delirium. Large randomized should be avoided. In contrast, parenteral nutrition should be studies have failed to demonstrate the effectiveness of any started as soon as possible for severely malnourished patients, medication to prevent or treat delirium. Use of antipsychotics those at high risk for malnutrition, and those for whom enteral are controversial. with no conclusive evidence of benefit. nutrition is not possible. Benzodiazepines should not be used unless they are needed to TEV POIl{IS treat alcohol withdrawal or seizures. Treatment involves iden- tification and correction of the underlying cause, multicompo . Enteral nutrition is preferred and should be started within nent bundled interventions (Table a ), and maintaining 24to 48 hours of admission to the ICU. o In nonmalnourished patients, supplemental parenteral TABLE 44. ABCDEF Care Bundle for Managing Delirium nutrition should be considered only after 7 to 10 days of in the ICU meeting less than 60% of energr and protein requirements A: Assess, prevent, and manage pain by the enteral route alone. B: Perform Both SATand SBT . In patients receiving enteral feedings, measurement of C: Choice of sedation and analgesia gastric residuals is not recommended because it delays HVC achievement offeeding goals, increases the risk ofclog- D: Delirium: assessment, prevention, and management ging the enteral access, and may increase the risk for E: Early mobility and exercise aspiration. F: Family engagement and empowerment o Administration of parenteral nutrition to supplement HVC enteral nutrition may lead to harm and should be avoided. 60

Principles of Critical Care a Early Mobilization TA8LE 45. ICU Care Bundles Many factors contribute to weakness in criticalty ill patients, Ventilator-Associated Pneumoniaa including immobility, disease, medications, and medical inter Head of bed elevated at least 30 degrees ventions. Immobility may result in muscular weakness, joint Daily sedation interruption and assessment of readiness to stiffness, pressure ulcers, osteoporosis, gastrointestinal dys- extu bate motiliry and dysautonomia. Even a lew days olimmobility can Endotracheal tubes with subglottic suction have a prolonged effect on muscular strength; long term follow-up of patients with critical illness demonstrates persis Early exercise or mobilization for physical conditioning tent weakness at 1 and 5 years. Mobilization and exercise are Change ventilator circuits only if malfunctioning or visibly soiled intuitive strategies to solve this problem, and although evi Central Line-Associated Bloodstream lnfectionsb dence is not yet conclusive, the risk/beneflt analysis favors Hand hygiene their application. Mobilization strategies consisting of inter Maximal barrier precautions ruption ofsedation and physical and occupational therapy in Chlorhexidine skin antisepsis the earliest days ofcritical illness are associated with decreased length of ICU stay and hospital stay, decreased days receiving Avoid femoral access mechanical ventilation, and improvements in quality of life j Daily review of line necessity and functional status. Sepsis' I(EY POIl{T I -hour bundle

tent weakness at 1 and 5 years. Mobilization and exercise are Change ventilator circuits only if malfunctioning or visibly soiled intuitive strategies to solve this problem, and although evi Central Line-Associated Bloodstream lnfectionsb dence is not yet conclusive, the risk/beneflt analysis favors Hand hygiene their application. Mobilization strategies consisting of inter Maximal barrier precautions ruption ofsedation and physical and occupational therapy in Chlorhexidine skin antisepsis the earliest days ofcritical illness are associated with decreased length of ICU stay and hospital stay, decreased days receiving Avoid femoral access mechanical ventilation, and improvements in quality of life j Daily review of line necessity and functional status. Sepsis' I(EY POIl{T I -hour bundle . The use of early mobilization strategies decreases length I Measure lactate level of time in the ICU and hospital and improves functional Obtain blood cultures before antibiotics status and quality of life. Administer broad-spectrum antibiotics Administer 30 mUkg crystalloids for hypotension or lactate ICU Care Bundles >4 mEq/L(4 mmol/L) An ICU care bundle is a series ofinterventions that have been Use vasopressors if no response to fluids; keep MAP above shown to improve patient outcomes when used together. 65 mm Hg Bundles can help clinicians monitor patients and guide appro N4AP = mean arterial blood pressure, calculated as [(2 x d astolic) + systolic]/3. priate interventions. Three care bundles that apply to critical 'Recommendations based on Klompas M, Branson R, Elchenwald EC, et al; Society care are summarized in Table 45. for Healthcare Epidemiology of America (SHEA). Strategies to prevent ventilator associated pneumonia in acute care hospitals:2014 update. lnfect Control Hosp Epidemiol. 20 1 4;35:9 1 5 36. IPMl D: 25026607] doi:10.1086/677 1 44 High Value Care in the ICU l'Recommendations {rom the lnstitute for Healthcare lmprovement. Critical care is responsible for a large proportion of U.S. 'Recommendat ons based on Levy MM, Evans LE, Rhodes A. The Surviving Sepsis health care costs. I{owever, survir,al and quality of life out Campaign bundle: 201 B update IEditorial]. lntensive Care Med.2018:44:925 928. {PMID: 29675s661 doi:10.1007/s00134 018 5085-0 comes are not that different lrom other top economy coun tries. Societal, organizational, and payment pressures have encouraged a focus on providing high value care, defined as Respiratory Support care that balances clinical benefit with cost and harm. with Admission to the ICU for respiratory insulliciency is prompted by the goal of improving patient outcomes. The ICU is an envi- three basic conditions: hy,poxemic respiratory failure, hypercapnic ronment in which high value care can have major effects, as respiratory (ventilatory) failure, and upper airway impairment. the resources are expensive and the culture favors aggressive Acute hypoxemic respiratory failure is caused by shunting resource use. Internal medicine and critical care medical (perfusion of lung units that are not ventilated) because of societies have joined the American Board of Internal Medicine alveolar collapse or f)ooding with cells, fluid, or blood. Therapies Foundation's Choosing Wisely' campaign to promote cost fbr hypoxemia include increasing the inhaled oxygen concen eflective strategies that improve patient care and avoid waste tration or applying positive end expiratory pressure to open up and harm. h 2021 the Society of Critical Care Medicine's flooded or collapsed alveoli. Choosing Wisely recommendations (https'i/www.choosing Acute hypercapnic respiratory failure is caused by dead wisely.org/societies/society of critical care medicine/) space (ventilation of poorly perlused lung units) or pump fail addressed the overuse ofthe fbllowing critical care practices: ure (inability to move air in and out of the lungs). Adequate (t) retaining catheters and drains withtiut a clear indication, ventilation requires suflicient pressure from the respiratory (2) delaying discontinuation of mechanical ventilation, (3) muscles to move air to the alveoli. The pressure generated has continuing antibiotic therapy without need, (4) delaying to overcome both elastic (chest wall and lung) and resistive mobilization of critically ill patients, and (5) providing care (airway) forces. Ventilatory failure can result from elastic and without ensuring that it aligns with patient preferences. The resistive lbrces that are too high or respiratory muscles that are 2014 Choosing Wisely- list included a recommendation too weak. Mechanical ventilation (invasive or noninvasive) is against daily routine laboratory testing. the mainstay treatment for hypercapnia.

. The use of early mobilization strategies decreases length I Measure lactate level of time in the ICU and hospital and improves functional Obtain blood cultures before antibiotics status and quality of life. Administer broad-spectrum antibiotics Administer 30 mUkg crystalloids for hypotension or lactate ICU Care Bundles >4 mEq/L(4 mmol/L) An ICU care bundle is a series ofinterventions that have been Use vasopressors if no response to fluids; keep MAP above shown to improve patient outcomes when used together. 65 mm Hg Bundles can help clinicians monitor patients and guide appro N4AP = mean arterial blood pressure, calculated as [(2 x d astolic) + systolic]/3. priate interventions. Three care bundles that apply to critical 'Recommendations based on Klompas M, Branson R, Elchenwald EC, et al; Society care are summarized in Table 45. for Healthcare Epidemiology of America (SHEA). Strategies to prevent ventilator associated pneumonia in acute care hospitals:2014 update. lnfect Control Hosp Epidemiol. 20 1 4;35:9 1 5 36. IPMl D: 25026607] doi:10.1086/677 1 44 High Value Care in the ICU l'Recommendations {rom the lnstitute for Healthcare lmprovement. Critical care is responsible for a large proportion of U.S. 'Recommendat ons based on Levy MM, Evans LE, Rhodes A. The Surviving Sepsis health care costs. I{owever, survir,al and quality of life out Campaign bundle: 201 B update IEditorial]. lntensive Care Med.2018:44:925 928. {PMID: 29675s661 doi:10.1007/s00134 018 5085-0 comes are not that different lrom other top economy coun tries. Societal, organizational, and payment pressures have encouraged a focus on providing high value care, defined as Respiratory Support care that balances clinical benefit with cost and harm. with Admission to the ICU for respiratory insulliciency is prompted by the goal of improving patient outcomes. The ICU is an envi- three basic conditions: hy,poxemic respiratory failure, hypercapnic ronment in which high value care can have major effects, as respiratory (ventilatory) failure, and upper airway impairment. the resources are expensive and the culture favors aggressive Acute hypoxemic respiratory failure is caused by shunting resource use. Internal medicine and critical care medical (perfusion of lung units that are not ventilated) because of societies have joined the American Board of Internal Medicine alveolar collapse or f)ooding with cells, fluid, or blood. Therapies Foundation's Choosing Wisely' campaign to promote cost fbr hypoxemia include increasing the inhaled oxygen concen eflective strategies that improve patient care and avoid waste tration or applying positive end expiratory pressure to open up and harm. h 2021 the Society of Critical Care Medicine's flooded or collapsed alveoli. Choosing Wisely recommendations (https'i/www.choosing Acute hypercapnic respiratory failure is caused by dead wisely.org/societies/society of critical care medicine/) space (ventilation of poorly perlused lung units) or pump fail addressed the overuse ofthe fbllowing critical care practices: ure (inability to move air in and out of the lungs). Adequate (t) retaining catheters and drains withtiut a clear indication, ventilation requires suflicient pressure from the respiratory (2) delaying discontinuation of mechanical ventilation, (3) muscles to move air to the alveoli. The pressure generated has continuing antibiotic therapy without need, (4) delaying to overcome both elastic (chest wall and lung) and resistive mobilization of critically ill patients, and (5) providing care (airway) forces. Ventilatory failure can result from elastic and without ensuring that it aligns with patient preferences. The resistive lbrces that are too high or respiratory muscles that are 2014 Choosing Wisely- list included a recommendation too weak. Mechanical ventilation (invasive or noninvasive) is against daily routine laboratory testing. the mainstay treatment for hypercapnia. 61

I Principles of Critical Care Upper airway impairment is usually a manifestation of Mechanical Ventilatory Support: : either obstruction of the airway (e.g., angioedema) or inabil- General Principles ity to protect the airway (e.g., opiate intoxication). The man Mechanical ventilator support for respiratory failure is accom .

Upper airway impairment is usually a manifestation of Mechanical Ventilatory Support: : either obstruction of the airway (e.g., angioedema) or inabil- General Principles ity to protect the airway (e.g., opiate intoxication). The man Mechanical ventilator support for respiratory failure is accom . agement is to maintain a patent airway (e.g., endotracheal plished by noninvasive positive pressure ventilation (NPPV)' tube, tracheostomy, or cricothyrotomy) (see Common ICU using a helmet, nasal, oral, or full face mask, or invasive ven Conditions). tilation with an endotracheal tube or tracheostomy. Selection of NPPV or invasive ventilation is dependent on the clinical Orygen Therapy situation and the goals of treatment. lnitiation of any form of Several devices deliver oxygen, each with different charac mechanical ventilatory support should be performed in a l teristics that serve patients differently. These devices are monitored unit (emergency department or ICU). : titrated most often to maintain a "normal" arterial oxygen saturation (Saor) or pulse oximetry (Spoz). However, higher Noninvasive Positive Pressure Ventilation oxygen saturation is not always desirable. Evidence now sug There are two types of NPPV: continuous positive airway pres- gests that supplementing oxygen for patients whose oxygen sure and bilevel positive airway pressure. Continuous positive saturation is already 96"/,, or higher actually increases ntor airway pressure delivers a constant airway pressure during tality. Recommendations include both that an Spo, of 96"/,, or inspiration and expiration. Bilevel positive airway pressure lower should be maintained in patients receiving oxygen delivers a higher level of positive airway pressure during inspi therapy and that oxygen therapy should not be started for ration than during expiration, thus providing additional patients with acute myocardial infarction or stroke and an inspiratory support and increased tidal volume. The support is Spo, of 93"/,, or higher. These guidelines do not apply to all titrated to an appropriate level olgas exchange and to optimize acute medical conditions. For example, higher Sao2 values patient respiratory effort. Table 46 highlights the physiologic are beneficial for patients with carbon monoxide poisoning effects and indications for these different modes of ventilatory (a specific case in which Spo, may be unreliable and Sao, support. should be used instead), cluster headache, sickle cell crisis, and pneumothorax. lndicetions and Patient Selection Evidence favors the use ofNPPV in the critical care setting in High-Flow Nosol Connulo patients with COPD exacerbations. cardiogenic pulmonary High flow nasal mixes and humidifies high flow air and oxy edema, neuromuscular disease, or obesity hypoventilation gen (30 L/min or more) to deliver a consistent Fro, (0.21 1.0) syndrome and in patients at high risk of failing extubation through a nasal cannula. The high flow creates some positive (e.g., those >65 years old or with heart lailure or COPD). airway pressure, but the amount depends on the flow rate and However, NPPV also increases the risk lor mortality in some cannot be quantified. High-flow nasal cannula can decrease patients, such as those with COPD exacerbations who failed respiratory rate, work of breathing, and dead space. It has NPPV and require subsequent intubation. AII patients placed physiological and patient comfort appeal, but the evidence is on NPPV need to be monitored and reevaluated within 2 hours developing. Systematic reviews have found no difference in to determine whether the therapy is effective and whether hypoxemic events compared with other methods used to oxy- adjustments are needed. genate critically ill patients before and during intubation. There is evidence suggesting harm when intubation is In managing acute hypoxemic respiratory failure, it may delayed or when tidal volumes are too high because of NPPV. decrease the need for tracheal intubation. but it has no dem- Contraindications to the use ofNPPV include persistent altered onstrated effect on patient mortality. Current guidelines rec mental status, increased airway secretions, emesis, gastric ommend high-flow nasal cannula because the reduced risk distention, airway obstruction, recent esophageal surgery. car- for intubation is important to patients. In the postextubation diac arrest, inability to protect the airway, facial traumarsur period, high flow oxygen may reduce the risk for recurrent gery (including oral, nasal, or sinus). and patient intolerance of respiratory failure and reintubation. In high-risk patients the mask. (older than 65 years or r,l'ith chronic heart or lung disease), high flow alone was less effective than high flow plus nonin- Application vasive ventilation immediately after extubation in preventing Proper mask sizing and patient adaptation to the device are reintubation. essential; these require time and coaching ofthe patient. The The initial application of high flow nasal cannula should timing of NPPV is very important, as late application (impend- occur in the critical care setting with close monitoring for ing respiratory failure) is associated both with the need for tolerance and effectiveness. In patients with acute hypoxemic subsequent intubation and with worse outcomes. After initia- respiratory failure who are receiving high flow oxygen, the tion, patients should be closely monitored for tolerance and ROX index, defined as the ratio of Spor/Fro, ('2,) to respiratory adverse effects (patient comfbrt, skin integrity, gastric disten- rate (breaths/min), is a validated score that helps identify tion, and eye irritation), effectiveness of the ventilatory patients at low or high risk for intubation. parameters (tidal volumes and respiration rate), and clinical

agement is to maintain a patent airway (e.g., endotracheal plished by noninvasive positive pressure ventilation (NPPV)' tube, tracheostomy, or cricothyrotomy) (see Common ICU using a helmet, nasal, oral, or full face mask, or invasive ven Conditions). tilation with an endotracheal tube or tracheostomy. Selection of NPPV or invasive ventilation is dependent on the clinical Orygen Therapy situation and the goals of treatment. lnitiation of any form of Several devices deliver oxygen, each with different charac mechanical ventilatory support should be performed in a l teristics that serve patients differently. These devices are monitored unit (emergency department or ICU). : titrated most often to maintain a "normal" arterial oxygen saturation (Saor) or pulse oximetry (Spoz). However, higher Noninvasive Positive Pressure Ventilation oxygen saturation is not always desirable. Evidence now sug There are two types of NPPV: continuous positive airway pres- gests that supplementing oxygen for patients whose oxygen sure and bilevel positive airway pressure. Continuous positive saturation is already 96"/,, or higher actually increases ntor airway pressure delivers a constant airway pressure during tality. Recommendations include both that an Spo, of 96"/,, or inspiration and expiration. Bilevel positive airway pressure lower should be maintained in patients receiving oxygen delivers a higher level of positive airway pressure during inspi therapy and that oxygen therapy should not be started for ration than during expiration, thus providing additional patients with acute myocardial infarction or stroke and an inspiratory support and increased tidal volume. The support is Spo, of 93"/,, or higher. These guidelines do not apply to all titrated to an appropriate level olgas exchange and to optimize acute medical conditions. For example, higher Sao2 values patient respiratory effort. Table 46 highlights the physiologic are beneficial for patients with carbon monoxide poisoning effects and indications for these different modes of ventilatory (a specific case in which Spo, may be unreliable and Sao, support. should be used instead), cluster headache, sickle cell crisis, and pneumothorax. lndicetions and Patient Selection Evidence favors the use ofNPPV in the critical care setting in High-Flow Nosol Connulo patients with COPD exacerbations. cardiogenic pulmonary High flow nasal mixes and humidifies high flow air and oxy edema, neuromuscular disease, or obesity hypoventilation gen (30 L/min or more) to deliver a consistent Fro, (0.21 1.0) syndrome and in patients at high risk of failing extubation through a nasal cannula. The high flow creates some positive (e.g., those >65 years old or with heart lailure or COPD). airway pressure, but the amount depends on the flow rate and However, NPPV also increases the risk lor mortality in some cannot be quantified. High-flow nasal cannula can decrease patients, such as those with COPD exacerbations who failed respiratory rate, work of breathing, and dead space. It has NPPV and require subsequent intubation. AII patients placed physiological and patient comfort appeal, but the evidence is on NPPV need to be monitored and reevaluated within 2 hours developing. Systematic reviews have found no difference in to determine whether the therapy is effective and whether hypoxemic events compared with other methods used to oxy- adjustments are needed. genate critically ill patients before and during intubation. There is evidence suggesting harm when intubation is In managing acute hypoxemic respiratory failure, it may delayed or when tidal volumes are too high because of NPPV. decrease the need for tracheal intubation. but it has no dem- Contraindications to the use ofNPPV include persistent altered onstrated effect on patient mortality. Current guidelines rec mental status, increased airway secretions, emesis, gastric ommend high-flow nasal cannula because the reduced risk distention, airway obstruction, recent esophageal surgery. car- for intubation is important to patients. In the postextubation diac arrest, inability to protect the airway, facial traumarsur period, high flow oxygen may reduce the risk for recurrent gery (including oral, nasal, or sinus). and patient intolerance of respiratory failure and reintubation. In high-risk patients the mask. (older than 65 years or r,l'ith chronic heart or lung disease), high flow alone was less effective than high flow plus nonin- Application vasive ventilation immediately after extubation in preventing Proper mask sizing and patient adaptation to the device are reintubation. essential; these require time and coaching ofthe patient. The The initial application of high flow nasal cannula should timing of NPPV is very important, as late application (impend- occur in the critical care setting with close monitoring for ing respiratory failure) is associated both with the need for tolerance and effectiveness. In patients with acute hypoxemic subsequent intubation and with worse outcomes. After initia- respiratory failure who are receiving high flow oxygen, the tion, patients should be closely monitored for tolerance and ROX index, defined as the ratio of Spor/Fro, ('2,) to respiratory adverse effects (patient comfbrt, skin integrity, gastric disten- rate (breaths/min), is a validated score that helps identify tion, and eye irritation), effectiveness of the ventilatory patients at low or high risk for intubation. parameters (tidal volumes and respiration rate), and clinical 62

Principles of Critical Care TABLE 46, Modes of Noninvasive Positive Pressure Ventilation Mode Function Physiotogic Effects lndications CPAP Applies and maintains a constant Maintains patent airway in the setting Obstructive sleep apnea airway pressure throughout the of obstructive sleep apnea, increases respiratory cycle Pulmonary edema functional residual capacity, increases mean airway pressure Excessive dynamic airway collapse Preintubation Postextubation PAP Applies two different levels of airway Same as CPAB but also decreases COPD exacerbation pressure: IPAP and EPAP work of breathing and augments tidal volume Obesity hypoventilation syndrome Neuromuscular diseases Time-limited trial in selected "do not intubate" patients with clear goals of care BPAP with BPAP with a minimum set respiration ln case o{ apnea, continues to deliver Hypoventilation, central apneas S/T mode rate breaths

TABLE 46, Modes of Noninvasive Positive Pressure Ventilation Mode Function Physiotogic Effects lndications CPAP Applies and maintains a constant Maintains patent airway in the setting Obstructive sleep apnea airway pressure throughout the of obstructive sleep apnea, increases respiratory cycle Pulmonary edema functional residual capacity, increases mean airway pressure Excessive dynamic airway collapse Preintubation Postextubation PAP Applies two different levels of airway Same as CPAB but also decreases COPD exacerbation pressure: IPAP and EPAP work of breathing and augments tidal volume Obesity hypoventilation syndrome Neuromuscular diseases Time-limited trial in selected "do not intubate" patients with clear goals of care BPAP with BPAP with a minimum set respiration ln case o{ apnea, continues to deliver Hypoventilation, central apneas S/T mode rate breaths BPAP = bilevel positive airway pressure; CPAP = continuous positive airway pressure; EPAP = expiratory positive aimay pressure; IPAP = inspiratory positive airway pressure; S/T = spontaneous/timed.

TABLE 46, Modes of Noninvasive Positive Pressure Ventilation Mode Function Physiotogic Effects lndications CPAP Applies and maintains a constant Maintains patent airway in the setting Obstructive sleep apnea airway pressure throughout the of obstructive sleep apnea, increases respiratory cycle Pulmonary edema functional residual capacity, increases mean airway pressure Excessive dynamic airway collapse Preintubation Postextubation PAP Applies two different levels of airway Same as CPAB but also decreases COPD exacerbation pressure: IPAP and EPAP work of breathing and augments tidal volume Obesity hypoventilation syndrome Neuromuscular diseases Time-limited trial in selected "do not intubate" patients with clear goals of care BPAP with BPAP with a minimum set respiration ln case o{ apnea, continues to deliver Hypoventilation, central apneas S/T mode rate breaths BPAP = bilevel positive airway pressure; CPAP = continuous positive airway pressure; EPAP = expiratory positive aimay pressure; IPAP = inspiratory positive airway pressure; S/T = spontaneous/timed. improvement (blood pH, respiration rate, oxygen saturation, Daily spontaneous breathing trials assess the readiness to and mental status). breathe unassisted. The current recommendation is to perform trials of at least 30 minutes and no more than 2 hours in length, Invasive Mechanical Ventilation using low levels of pressure support (<B cm HrO) or a T piece to Invasive mechanical ventilation involves the use of an endotra identiflz patients who can be evaluated for extubation. cheal tube or tracheostomy to deliver positive pressure ventila Synchronized intermittent mandatory ventilation is a tion. The indications for invasive mechanical ventilation are mode of ventilation that combines mandatory and spontane hypoxemic or hypercapnic respiratory failure, contraindica- ous breaths. It should not be used to wean patients from tion to NPPV and inability to protect the airway. The timing, mechanical ventilation. the ventilation mode, and the settings depend on disease and t( EY PO t 1{rS patient factors (Table 47). The appropriate mode of invasive mechanical ventilation is . Spontaneous breathing trials of from 30 minutes to 2 hours chosen on the basis of mode characteristics that favor the pre using low levels ofpressure support (B cm HrO or less) can identiSr patients who may be evaluated for vailing clinical goal, based on the patient's disease and physio logic status. When safety is the priority, the settings focus on extubation. lung protective ventilation, meaning adequate minute ventila . The use of NPPV immediately after extubation can pre tion and oxygenation while maintaining the lowest effective vent extubation failure in patients at high risk, such as tidal volume and plateau pressure to prevent ventilator those with heart failure, COPD, or hypercapnia. induced lung injury (see Common ICU Conditions). Ventilator induced lung injury can occur early or late in the course of Hemodynamic Support ventilation and results from the overdistension of alveoli Patients in the ICU sometimes require invasive tools for hemo ("volutrauma") or the collapse of alveoli with expiration dynamic monitoring. These devices increase the risk for ("atelectrauma"). adverse events, so they should be used only when sufficient When patients are awake and the risk for lung injury has infbrmation cannot be obtained with noninvasive methods decreased, the prevailing goal becomes comfort. Patient and should be removed as soon as possible. For example, ventilator interaction should be optimized to provide comFort routine use of pulmonary artery catheters does not lead to using a mode that allows synchrony and adequate support. improved outcomes, is associated with increased complica Considerations include the patient's respiratory muscle weak tions, and may increase mortality. ness or fatigue, the presence of acidosis, and level of sedation. lntravenous Access Weaning There are several devices available to achieve central intravenous Patients should be liberated from mechanical ventilation as (lV) access. Use depends on many factors, including urgenc'y, soon as possible. The concurrent use ofdaily awakening or tar- expected duration, and reason frrr access (Tabb a9). Peripheral geted light sedation protocols and spontaneous breathing trials venous access with a short, wide bore catheter is the route of reduces mechanical ventilation time and mortalily (Table a8). choice for rapid volume resuscitation. Removal of intraosseous

improvement (blood pH, respiration rate, oxygen saturation, Daily spontaneous breathing trials assess the readiness to and mental status). breathe unassisted. The current recommendation is to perform trials of at least 30 minutes and no more than 2 hours in length, Invasive Mechanical Ventilation using low levels of pressure support (<B cm HrO) or a T piece to Invasive mechanical ventilation involves the use of an endotra identiflz patients who can be evaluated for extubation. cheal tube or tracheostomy to deliver positive pressure ventila Synchronized intermittent mandatory ventilation is a tion. The indications for invasive mechanical ventilation are mode of ventilation that combines mandatory and spontane hypoxemic or hypercapnic respiratory failure, contraindica- ous breaths. It should not be used to wean patients from tion to NPPV and inability to protect the airway. The timing, mechanical ventilation. the ventilation mode, and the settings depend on disease and t( EY PO t 1{rS patient factors (Table 47). The appropriate mode of invasive mechanical ventilation is . Spontaneous breathing trials of from 30 minutes to 2 hours chosen on the basis of mode characteristics that favor the pre using low levels ofpressure support (B cm HrO or less) can identiSr patients who may be evaluated for vailing clinical goal, based on the patient's disease and physio logic status. When safety is the priority, the settings focus on extubation. lung protective ventilation, meaning adequate minute ventila . The use of NPPV immediately after extubation can pre tion and oxygenation while maintaining the lowest effective vent extubation failure in patients at high risk, such as tidal volume and plateau pressure to prevent ventilator those with heart failure, COPD, or hypercapnia. induced lung injury (see Common ICU Conditions). Ventilator induced lung injury can occur early or late in the course of Hemodynamic Support ventilation and results from the overdistension of alveoli Patients in the ICU sometimes require invasive tools for hemo ("volutrauma") or the collapse of alveoli with expiration dynamic monitoring. These devices increase the risk for ("atelectrauma"). adverse events, so they should be used only when sufficient When patients are awake and the risk for lung injury has infbrmation cannot be obtained with noninvasive methods decreased, the prevailing goal becomes comfort. Patient and should be removed as soon as possible. For example, ventilator interaction should be optimized to provide comFort routine use of pulmonary artery catheters does not lead to using a mode that allows synchrony and adequate support. improved outcomes, is associated with increased complica Considerations include the patient's respiratory muscle weak tions, and may increase mortality. ness or fatigue, the presence of acidosis, and level of sedation. lntravenous Access Weaning There are several devices available to achieve central intravenous Patients should be liberated from mechanical ventilation as (lV) access. Use depends on many factors, including urgenc'y, soon as possible. The concurrent use ofdaily awakening or tar- expected duration, and reason frrr access (Tabb a9). Peripheral geted light sedation protocols and spontaneous breathing trials venous access with a short, wide bore catheter is the route of reduces mechanical ventilation time and mortalily (Table a8). choice for rapid volume resuscitation. Removal of intraosseous 63

Principles of Critical Care TABLE 47. Most Frequently Used Ventilator Modes Common Name Mode Breath Control Breath Sequence Targeting Scheme Characteristics Classification Variable Volume control VC-CMVs VC: The ventilator CMV: AII breaths are Set-point, s: The Ensures minimum assisVcontrol controls the flow mandatory. The operator sets all minute ventilation (volume) during the patient may or may parameters of the Abilityto limittidal mandatory breath. lf not trigger the breath (flow volume delivered the patient's effort, breath, but the waveform, flow rate, lung compliance, or ventilator always and volume). The Least likely to allow resistance changes, ends (cycles) the ventilator does not comfort for patient the ventilator will still breath when the tidal adjust to the patient's because of limitation deliver the set tidal volume is delivered. effort or change in in flow volume- lung characteristics. Serves the goal of safety Pressure control PC-CMVs PC: The ventilator CMV: All breaths are Set-point, s: The Ensures pressure will assisVcontrol controls the pressure mandatory. The operator sets all not rise above a set during the mandatory patient may or may parameters of the limit breath. lf the patient's not trigger the breath (inspiratory Tidal volume is effort, lung breath, but the pressure and dependent on compliance, or ventilator always inspiratory time). The patient effort, lung resistance changes, ends the breath ventilator does not compliance, and the ventilator will still when the preset adjust to the patient's resistance deliverthe set inspiratory time effort or change in inspiratory pressure elapses. lung characteristics. Serves the goal o{ (butthe tidal volume safety(if tidalvolume delivered will change). within range) Pressure support, PC-CSVs PC: The ventilator CSV: All breaths are Set-point, s: The Patient determines continuous controls the pressure spontaneous. The operator sets all size and timing of positive airway during the breath. patient triggers and parameters of the breaths pressure cycles the breath. breath (inspiratory Serves the goal of pressure). The comfort, as it allows ventilator delivers the synchrony with patient breath and does not adjust to the patient's Can be used to effort or change in assess extubation lung characteristics. readiness Synchronized PC-lMVs,s or PC orVC: The IMV: Preset Set-point, s: One "s" Provides a minimum intermittent VC-lMVs,s mandatory breaths mandatory breaths refers to the set amount of mandatory can be set to be are delivered by mandatory breath mandatory breaths ventilation volume or pressure the ventilator at a and the other to the Allows spontaneous controlled, not both. minimum set rate. spontaneous breath. breaths Spontaneous breaths Generally, all are permitted in spontaneous breaths Serves the goal of between mandatory in IMV are pressure safety, as it allows a breaths. The supported (PC-CSVs). minimum minute triggering of the ventilation mandatory breath will be coordinated with the patient if the inspiratory effort occurs close to the scheduled time trigger.

TABLE 47. Most Frequently Used Ventilator Modes Common Name Mode Breath Control Breath Sequence Targeting Scheme Characteristics Classification Variable Volume control VC-CMVs VC: The ventilator CMV: AII breaths are Set-point, s: The Ensures minimum assisVcontrol controls the flow mandatory. The operator sets all minute ventilation (volume) during the patient may or may parameters of the Abilityto limittidal mandatory breath. lf not trigger the breath (flow volume delivered the patient's effort, breath, but the waveform, flow rate, lung compliance, or ventilator always and volume). The Least likely to allow resistance changes, ends (cycles) the ventilator does not comfort for patient the ventilator will still breath when the tidal adjust to the patient's because of limitation deliver the set tidal volume is delivered. effort or change in in flow volume- lung characteristics. Serves the goal of safety Pressure control PC-CMVs PC: The ventilator CMV: All breaths are Set-point, s: The Ensures pressure will assisVcontrol controls the pressure mandatory. The operator sets all not rise above a set during the mandatory patient may or may parameters of the limit breath. lf the patient's not trigger the breath (inspiratory Tidal volume is effort, lung breath, but the pressure and dependent on compliance, or ventilator always inspiratory time). The patient effort, lung resistance changes, ends the breath ventilator does not compliance, and the ventilator will still when the preset adjust to the patient's resistance deliverthe set inspiratory time effort or change in inspiratory pressure elapses. lung characteristics. Serves the goal o{ (butthe tidal volume safety(if tidalvolume delivered will change). within range) Pressure support, PC-CSVs PC: The ventilator CSV: All breaths are Set-point, s: The Patient determines continuous controls the pressure spontaneous. The operator sets all size and timing of positive airway during the breath. patient triggers and parameters of the breaths pressure cycles the breath. breath (inspiratory Serves the goal of pressure). The comfort, as it allows ventilator delivers the synchrony with patient breath and does not adjust to the patient's Can be used to effort or change in assess extubation lung characteristics. readiness Synchronized PC-lMVs,s or PC orVC: The IMV: Preset Set-point, s: One "s" Provides a minimum intermittent VC-lMVs,s mandatory breaths mandatory breaths refers to the set amount of mandatory can be set to be are delivered by mandatory breath mandatory breaths ventilation volume or pressure the ventilator at a and the other to the Allows spontaneous controlled, not both. minimum set rate. spontaneous breath. breaths Spontaneous breaths Generally, all are permitted in spontaneous breaths Serves the goal of between mandatory in IMV are pressure safety, as it allows a breaths. The supported (PC-CSVs). minimum minute triggering of the ventilation mandatory breath will be coordinated with the patient if the inspiratory effort occurs close to the scheduled time trigger. controlled

TABLE 47. Most Frequently Used Ventilator Modes Common Name Mode Breath Control Breath Sequence Targeting Scheme Characteristics Classification Variable Volume control VC-CMVs VC: The ventilator CMV: AII breaths are Set-point, s: The Ensures minimum assisVcontrol controls the flow mandatory. The operator sets all minute ventilation (volume) during the patient may or may parameters of the Abilityto limittidal mandatory breath. lf not trigger the breath (flow volume delivered the patient's effort, breath, but the waveform, flow rate, lung compliance, or ventilator always and volume). The Least likely to allow resistance changes, ends (cycles) the ventilator does not comfort for patient the ventilator will still breath when the tidal adjust to the patient's because of limitation deliver the set tidal volume is delivered. effort or change in in flow volume- lung characteristics. Serves the goal of safety Pressure control PC-CMVs PC: The ventilator CMV: All breaths are Set-point, s: The Ensures pressure will assisVcontrol controls the pressure mandatory. The operator sets all not rise above a set during the mandatory patient may or may parameters of the limit breath. lf the patient's not trigger the breath (inspiratory Tidal volume is effort, lung breath, but the pressure and dependent on compliance, or ventilator always inspiratory time). The patient effort, lung resistance changes, ends the breath ventilator does not compliance, and the ventilator will still when the preset adjust to the patient's resistance deliverthe set inspiratory time effort or change in inspiratory pressure elapses. lung characteristics. Serves the goal o{ (butthe tidal volume safety(if tidalvolume delivered will change). within range) Pressure support, PC-CSVs PC: The ventilator CSV: All breaths are Set-point, s: The Patient determines continuous controls the pressure spontaneous. The operator sets all size and timing of positive airway during the breath. patient triggers and parameters of the breaths pressure cycles the breath. breath (inspiratory Serves the goal of pressure). The comfort, as it allows ventilator delivers the synchrony with patient breath and does not adjust to the patient's Can be used to effort or change in assess extubation lung characteristics. readiness Synchronized PC-lMVs,s or PC orVC: The IMV: Preset Set-point, s: One "s" Provides a minimum intermittent VC-lMVs,s mandatory breaths mandatory breaths refers to the set amount of mandatory can be set to be are delivered by mandatory breath mandatory breaths ventilation volume or pressure the ventilator at a and the other to the Allows spontaneous controlled, not both. minimum set rate. spontaneous breath. breaths Spontaneous breaths Generally, all are permitted in spontaneous breaths Serves the goal of between mandatory in IMV are pressure safety, as it allows a breaths. The supported (PC-CSVs). minimum minute triggering of the ventilation mandatory breath will be coordinated with the patient if the inspiratory effort occurs close to the scheduled time trigger. controlled devices should be done within 24 hours of placement. In general, TIY POIXI' all [V access should be removed as soon as possible to decrease . All intravenous access should be removed as soon as the risk for infection or thrombosis. Procedure related compli possible to decrease the risk for complications. cations, such as arterial injury nerve injury bleeding, or pneu mothorax, can be minimized with the use of ultrasound guided o Peripheral intravenous access with a short, wide-bore placement. Devices with lower risk for complications (e.g., catheter is the route of choice for rapid volume resusci- peripheral IV access) should be prioritized whenever possible. tation.

devices should be done within 24 hours of placement. In general, TIY POIXI' all [V access should be removed as soon as possible to decrease . All intravenous access should be removed as soon as the risk for infection or thrombosis. Procedure related compli possible to decrease the risk for complications. cations, such as arterial injury nerve injury bleeding, or pneu mothorax, can be minimized with the use of ultrasound guided o Peripheral intravenous access with a short, wide-bore placement. Devices with lower risk for complications (e.g., catheter is the route of choice for rapid volume resusci- peripheral IV access) should be prioritized whenever possible. tation. 64

Principles of Critical Care TABLE 48. Common Criteria for Spontaneous Breathing Blood Pressure Support Trials and Extubation" A mean arterial pressure of 65 mm Hg is considered the Criteria to Perform 5BT threshold at which there is sufficient pressure for organ perfu Cause of respiratory failure improved sion in most humans. A study of higher (80-85 mm Hg) mean arterial pressures in patients with septic shock demonstrated Fto2<407" and PEEP <5-8 cm H2O no improvement in mortality. Blood pressure is usually moni pH>7.25 tored noninvasively with a blood pressure cuff. An arterial line Hemodynamic stability for continuous monitoring may be more useful than cuff pres- Able to spontaneously breathe sures when the systolic blood pressure is less than 90 mm Hg, Criteria to Pass 5BT-AI Least 3O Minutes Without the when frequent measurements are needed (particularly for Following: patients requiring continuous IV medication), or when the Clinical evidence of respiratory distress cuff readings are unreliable (in patients with morbid obesity, SpO2 <90% vascular anomalies of the extremities, or other anatomic fea- tures limiting cuff accuracy). Assessment of tissue perfusion Respiration rate >35/min includes physical examination (skin temperature, mottling, New arrhythmias jugular venous distention), measurement of vital signs, and Tachycardia focused cardiac evaluation with tools such as echocardiogra- Hypotension or hypertension phy and invasive and noninvasive cardiac output monitors. Additional Considerations Before Extubation These tools must be applied in the correct clinical scenario to

TABLE 48. Common Criteria for Spontaneous Breathing Blood Pressure Support Trials and Extubation" A mean arterial pressure of 65 mm Hg is considered the Criteria to Perform 5BT threshold at which there is sufficient pressure for organ perfu Cause of respiratory failure improved sion in most humans. A study of higher (80-85 mm Hg) mean arterial pressures in patients with septic shock demonstrated Fto2<407" and PEEP <5-8 cm H2O no improvement in mortality. Blood pressure is usually moni pH>7.25 tored noninvasively with a blood pressure cuff. An arterial line Hemodynamic stability for continuous monitoring may be more useful than cuff pres- Able to spontaneously breathe sures when the systolic blood pressure is less than 90 mm Hg, Criteria to Pass 5BT-AI Least 3O Minutes Without the when frequent measurements are needed (particularly for Following: patients requiring continuous IV medication), or when the Clinical evidence of respiratory distress cuff readings are unreliable (in patients with morbid obesity, SpO2 <90% vascular anomalies of the extremities, or other anatomic fea- tures limiting cuff accuracy). Assessment of tissue perfusion Respiration rate >35/min includes physical examination (skin temperature, mottling, New arrhythmias jugular venous distention), measurement of vital signs, and Tachycardia focused cardiac evaluation with tools such as echocardiogra- Hypotension or hypertension phy and invasive and noninvasive cardiac output monitors. Additional Considerations Before Extubation These tools must be applied in the correct clinical scenario to Ouantity of secretions: need for frequent suctioning minimize erroneous diagnostic results. Often, physical exami nation and vital signs alone are sufficient to make diagnostic Adequacy of cough conclusions. Management of hemodynamic perturbations Altered mental status should focus on the under$ing cause of hypotension. For PEEP = positive end-expiratory pressure; SBT = spontaneous breath trial; instance, hypotension resulting from deceased preload should SpO- = peripheral arter ral oxyqen saturatron. be initially treated with volume resuscitation. Support of blood "These criterra may drffer between rnstrlutronc. pressure may require the use of vasopressors (Table 5O).

Ouantity of secretions: need for frequent suctioning minimize erroneous diagnostic results. Often, physical exami nation and vital signs alone are sufficient to make diagnostic Adequacy of cough conclusions. Management of hemodynamic perturbations Altered mental status should focus on the under$ing cause of hypotension. For PEEP = positive end-expiratory pressure; SBT = spontaneous breath trial; instance, hypotension resulting from deceased preload should SpO- = peripheral arter ral oxyqen saturatron. be initially treated with volume resuscitation. Support of blood "These criterra may drffer between rnstrlutronc. pressure may require the use of vasopressors (Table 5O). TABLE 49. Types of Central Venous Access Type lndications Duration Potential Complications Contraindications Peripherally Delivery of potentially A few days to Low risk overall for Current or pending inserted central caustic medications such 1 year pneumothorax; reduced dialysis venous catheter as vasoactive agents, infection risk compared with sedatives, or antibiotics; nontunneled catheter; risk for clot central venous access formation or occlusion resulting from smaller vessel diameter Temporary Same as peripherally lnfection risk I nfection, site-specific nontu nneled inserted central venous increased after complications such as catheter; short-term 7 days pneumothorax for subclavian or dialysis, central venous low internal jugular approach pressure monitoring Long-term tunneled Long-term TPN, More than 6 weeks lnfection, same risks as chemotherapy, long-term nontunneled catheter during antibiotics, dialysis; placement tunneled Dacron cuff or other fabric allows tissue adherence to reduce infection and dislodgement Ports ortotally Long-term intermittent More than 6 weeks Lowest risk for infection, but implanted access such as more difficult to implant chemotherapy with more costs; hidden extravasation beneath skin lntraosseous (tibia When lV access otherwise About 24 hours Low risk for infection; flow Do not place in a bone or humeral head not attainable in emergent rates may be slower; if pain with a fracture, in a Iadults]) setting with infusion, can use 2% patient with a diagnosis preservative-free lidocaine of osteoporosis, or after injected slowly to control it a recent (24-48 h) intraosseous access attempt

TABLE 49. Types of Central Venous Access Type lndications Duration Potential Complications Contraindications Peripherally Delivery of potentially A few days to Low risk overall for Current or pending inserted central caustic medications such 1 year pneumothorax; reduced dialysis venous catheter as vasoactive agents, infection risk compared with sedatives, or antibiotics; nontunneled catheter; risk for clot central venous access formation or occlusion resulting from smaller vessel diameter Temporary Same as peripherally lnfection risk I nfection, site-specific nontu nneled inserted central venous increased after complications such as catheter; short-term 7 days pneumothorax for subclavian or dialysis, central venous low internal jugular approach pressure monitoring Long-term tunneled Long-term TPN, More than 6 weeks lnfection, same risks as chemotherapy, long-term nontunneled catheter during antibiotics, dialysis; placement tunneled Dacron cuff or other fabric allows tissue adherence to reduce infection and dislodgement Ports ortotally Long-term intermittent More than 6 weeks Lowest risk for infection, but implanted access such as more difficult to implant chemotherapy with more costs; hidden extravasation beneath skin lntraosseous (tibia When lV access otherwise About 24 hours Low risk for infection; flow Do not place in a bone or humeral head not attainable in emergent rates may be slower; if pain with a fracture, in a Iadults]) setting with infusion, can use 2% patient with a diagnosis preservative-free lidocaine of osteoporosis, or after injected slowly to control it a recent (24-48 h) intraosseous access attempt lV = intravenous; TPN = total parenteral nutrition.

TABLE 49. Types of Central Venous Access Type lndications Duration Potential Complications Contraindications Peripherally Delivery of potentially A few days to Low risk overall for Current or pending inserted central caustic medications such 1 year pneumothorax; reduced dialysis venous catheter as vasoactive agents, infection risk compared with sedatives, or antibiotics; nontunneled catheter; risk for clot central venous access formation or occlusion resulting from smaller vessel diameter Temporary Same as peripherally lnfection risk I nfection, site-specific nontu nneled inserted central venous increased after complications such as catheter; short-term 7 days pneumothorax for subclavian or dialysis, central venous low internal jugular approach pressure monitoring Long-term tunneled Long-term TPN, More than 6 weeks lnfection, same risks as chemotherapy, long-term nontunneled catheter during antibiotics, dialysis; placement tunneled Dacron cuff or other fabric allows tissue adherence to reduce infection and dislodgement Ports ortotally Long-term intermittent More than 6 weeks Lowest risk for infection, but implanted access such as more difficult to implant chemotherapy with more costs; hidden extravasation beneath skin lntraosseous (tibia When lV access otherwise About 24 hours Low risk for infection; flow Do not place in a bone or humeral head not attainable in emergent rates may be slower; if pain with a fracture, in a Iadults]) setting with infusion, can use 2% patient with a diagnosis preservative-free lidocaine of osteoporosis, or after injected slowly to control it a recent (24-48 h) intraosseous access attempt lV = intravenous; TPN = total parenteral nutrition. 65

Principles of Critical Care TABLE 50. Selection of Vasopressors and lnotropes Medication Type of Shock ReceptorTarget Primary Effect Comments Angiotensin ll Distributive AT II T SVR Role still being defined; concern for increase in thrombotic events Dobutamine (not a Cardiogenic 9,,F, t lnotropy First choice for cardiogenic shock without vasopressor) hypotension Distributive Add-on therapy for distributive shock with depressed cardiac function Dopamine (high-dose) Cardiogenic D, o,, F, t SVR, 1 inotropy Associated with increased mortality compared with norepinephrine in distributive shock; use only in cases of severe bradycardia in septic shock Dopamine (low-dose) Cardiogenic D, F, l lnotropy, l HR Not recommended to augment renal blood flow Epinephrine Cardiogenic at,0.z,Fr,Fz t SVR, 1 inotropy First choice anaphylactic (distributive) shock

Dobutamine (not a Cardiogenic 9,,F, t lnotropy First choice for cardiogenic shock without vasopressor) hypotension Distributive Add-on therapy for distributive shock with depressed cardiac function Dopamine (high-dose) Cardiogenic D, o,, F, t SVR, 1 inotropy Associated with increased mortality compared with norepinephrine in distributive shock; use only in cases of severe bradycardia in septic shock Dopamine (low-dose) Cardiogenic D, F, l lnotropy, l HR Not recommended to augment renal blood flow Epinephrine Cardiogenic at,0.z,Fr,Fz t SVR, 1 inotropy First choice anaphylactic (distributive) shock Distributive May be added to norepinephrine in septic (distributive) shock Hypovolemic Norepinephrine Cardiogenic Clr, CXZ, Dt t SVR, t inotropy First choice in cardiogenic, distributive, and hypovolemic shock Distributive Hypovolemic Phenylephrine Distributive ct1 1 SVR May be used when norepinephrine is contraindicated (tachyarrhythmias) or after failure of first-line drugs; may depress cardiac output by causing reflex bradycardia Vasopressin Distributive V T SVR May be added to norepinephrine in septic (distributive) shock; no role in other shock Hypovolemic states

Distributive May be added to norepinephrine in septic (distributive) shock Hypovolemic Norepinephrine Cardiogenic Clr, CXZ, Dt t SVR, t inotropy First choice in cardiogenic, distributive, and hypovolemic shock Distributive Hypovolemic Phenylephrine Distributive ct1 1 SVR May be used when norepinephrine is contraindicated (tachyarrhythmias) or after failure of first-line drugs; may depress cardiac output by causing reflex bradycardia Vasopressin Distributive V T SVR May be added to norepinephrine in septic (distributive) shock; no role in other shock Hypovolemic states AT ll = angiotensin type ll; HR = heart rate; SVR = systemic vascular resistance.

Distributive May be added to norepinephrine in septic (distributive) shock Hypovolemic Norepinephrine Cardiogenic Clr, CXZ, Dt t SVR, t inotropy First choice in cardiogenic, distributive, and hypovolemic shock Distributive Hypovolemic Phenylephrine Distributive ct1 1 SVR May be used when norepinephrine is contraindicated (tachyarrhythmias) or after failure of first-line drugs; may depress cardiac output by causing reflex bradycardia Vasopressin Distributive V T SVR May be added to norepinephrine in septic (distributive) shock; no role in other shock Hypovolemic states AT ll = angiotensin type ll; HR = heart rate; SVR = systemic vascular resistance. Norepinephrine is the most commonly used agent and has failure, severe illness, prolonged immobility, and hyper been shown to reduce mortality. However, other agents are glycemia. Evaluation for ICU-acquired weakness can ini- available and may be used in specific situations. tially be performed at the bedside, using the Medical Research Council muscle scale however, electromyogram XEY POIl{I testing remains the gold standard. ICU-acquired weakness HVC . A mean arterial pressure of 65 mm Hg is considered the generally improves over weeks to months, but it may per- threshold at which there is sufficient pressure for organ sist for years. Strategies to minimize ICU acquired weak- peffusion in most humans. ness include aggressive management of critical illness. early mobilization, and management of hyperglycemia.

Norepinephrine is the most commonly used agent and has failure, severe illness, prolonged immobility, and hyper been shown to reduce mortality. However, other agents are glycemia. Evaluation for ICU-acquired weakness can ini- available and may be used in specific situations. tially be performed at the bedside, using the Medical Research Council muscle scale however, electromyogram XEY POIl{I testing remains the gold standard. ICU-acquired weakness HVC . A mean arterial pressure of 65 mm Hg is considered the generally improves over weeks to months, but it may per- threshold at which there is sufficient pressure for organ sist for years. Strategies to minimize ICU acquired weak- peffusion in most humans. ness include aggressive management of critical illness. early mobilization, and management of hyperglycemia. ICU Complications XEY POIilI ICU complications maybe classified as early (occurring during . Strategies to minimize ICU-acquired weakness include the hospitalization) or late (persisting after the critical aggressive management of critical illness, early mobili- illness). zation, and management of hyperglycemia.

ICU complications maybe classified as early (occurring during . Strategies to minimize ICU-acquired weakness include the hospitalization) or late (persisting after the critical aggressive management of critical illness, early mobili- illness). zation, and management of hyperglycemia. ICU-Acquired Weakness Long-Term Cognitive lmpairment Between 25'1, and 100% of critically ill patients develop As many as 30% to 80'/n of patients with critical care illness muscle weakness. Muscle weakness may result from com- develop long term impairment in cognition, which manifests plications involving the nervous system (critical illness clinically as cognitive impairment. Observations have dem- polyneuropathy), the muscles themselves (critical illness onstrated that the level of impairment 1 year after critical myopathy), or some combination of both, or it may be illness is similar to mild Alzheimer disease. Although the nonspecific (lCU-acquired weakness). It may also be specific risk factors and interventions related to developing related to prolonged neuromuscular blockade. Table 51 cognitive impairment are not well defined, the development lists descriptions of types of ICU-acquired weakness. and duration of delirium during the ICU stay appear to be Identified risk factors include sepsis, multisystem organ major predictors. .\ 66

Common ICU Conditions TABLE 51 . Definitions and Characteristics of TABLE 5?. Radiographic Findings and Differential ICU-Acquired Weakness Diagnosis in Acute Respiratory Failure ICU-Acquired Weakness Finding Differential Diagnosis Clinically detected weakness with no explanation other than the No infiltrate Asthma/COPD exacerbation critical illness Drug overdose/toxicity Proximal and distal symmetricalflaccid weakness with sparing lntracardiac shunt of cranial nerves Neuromuscular weakness Often failure to wean from mechanical ventilation is the first indication of weakness Pulmonary embolus Diagnosis of exclusion Diffuse infiltrates Acute respiratory distress syndrome Critical lllness Polyneuropathy Cardiogenic pulmonary edema ICU-acquired weakness with electrophysiological evidence of Acute exacerbation of idiopathic axonal polyneuropathy pulmonary fibrosis Ouadriparesis or quadriplegia, decreased muscle tone, sparing Pneumonia of facial muscles; deep tendon reflexes decreased Other (e.g., acute hypersensitivity Critical lllness Myopathy pneumonitis, acute eosinophilic pneumonia) ICU-acquired weakness with electrophysiological or histological evidence of myopathy Focal infiltrate Airway obstruction Examination is similarto critical illness polyneuropathy; new Atelectasis sensory loss is suggestive; creatinine kinase may be elevated Pneumonia Critical lllness Neuromyopathy Pulmonary infarction Coexistence of critical lllness polyneuropathy and critical illness myopathy Mixed features; perhaps most prevalent form scan, arterial blood gas, and pulse oximetry are useful as part Prolonged Neuromuscular Blockade of a structured evaluation allowing clinicians to identify and Prolonged effects in patients with renal failure, liver failure, treat factors leading to respiratory failure. This approach hypermagnesemia includes evaluation for airway compromise, inadequate oxy Flaccid areflexic quadriplegia with cranial nerve involvement genation, and inadequate ventilation (Figure 25).

TABLE 51 . Definitions and Characteristics of TABLE 5?. Radiographic Findings and Differential ICU-Acquired Weakness Diagnosis in Acute Respiratory Failure ICU-Acquired Weakness Finding Differential Diagnosis Clinically detected weakness with no explanation other than the No infiltrate Asthma/COPD exacerbation critical illness Drug overdose/toxicity Proximal and distal symmetricalflaccid weakness with sparing lntracardiac shunt of cranial nerves Neuromuscular weakness Often failure to wean from mechanical ventilation is the first indication of weakness Pulmonary embolus Diagnosis of exclusion Diffuse infiltrates Acute respiratory distress syndrome Critical lllness Polyneuropathy Cardiogenic pulmonary edema ICU-acquired weakness with electrophysiological evidence of Acute exacerbation of idiopathic axonal polyneuropathy pulmonary fibrosis Ouadriparesis or quadriplegia, decreased muscle tone, sparing Pneumonia of facial muscles; deep tendon reflexes decreased Other (e.g., acute hypersensitivity Critical lllness Myopathy pneumonitis, acute eosinophilic pneumonia) ICU-acquired weakness with electrophysiological or histological evidence of myopathy Focal infiltrate Airway obstruction Examination is similarto critical illness polyneuropathy; new Atelectasis sensory loss is suggestive; creatinine kinase may be elevated Pneumonia Critical lllness Neuromyopathy Pulmonary infarction Coexistence of critical lllness polyneuropathy and critical illness myopathy Mixed features; perhaps most prevalent form scan, arterial blood gas, and pulse oximetry are useful as part Prolonged Neuromuscular Blockade of a structured evaluation allowing clinicians to identify and Prolonged effects in patients with renal failure, liver failure, treat factors leading to respiratory failure. This approach hypermagnesemia includes evaluation for airway compromise, inadequate oxy Flaccid areflexic quadriplegia with cranial nerve involvement genation, and inadequate ventilation (Figure 25). Repetitive nerve stimulation shows decremental response Acute Upper Airway Management In patients who cannot maintain a patent airway or protect themselves against aspiration, a cuffed endotracheal or tracheos- Post-lntensive Care Syndrome tomy tube should be placed. An oropharyngeal, nasopharyngeal, Post intensive care syndrome describes a group of symptoms that present in patients after an episode of critical care. The symptoms have been grouped according to the area that they Acute Respiratory Failure affect (physical impairment, mental health, and cognitive impairments). Patients with post-intensive care syndrome have increased health care use, increased morbidity and mor Secure Airway tality, and impaired quality of life. Post intensive care syn . Aimay patent? drome also affects the caregivers and family of the patient; it . Can patient protect airway? has been reported that family members experience anxiety, depression, and posttraumatic stress disorder. Current research and interventions are locusing on how to improve Assess Oxygenation recognition, prevention, diagnosis, and management. o Decreased oxygen saturation? . Widened A-a gradient?

Repetitive nerve stimulation shows decremental response Acute Upper Airway Management In patients who cannot maintain a patent airway or protect themselves against aspiration, a cuffed endotracheal or tracheos- Post-lntensive Care Syndrome tomy tube should be placed. An oropharyngeal, nasopharyngeal, Post intensive care syndrome describes a group of symptoms that present in patients after an episode of critical care. The symptoms have been grouped according to the area that they Acute Respiratory Failure affect (physical impairment, mental health, and cognitive impairments). Patients with post-intensive care syndrome have increased health care use, increased morbidity and mor Secure Airway tality, and impaired quality of life. Post intensive care syn . Aimay patent? drome also affects the caregivers and family of the patient; it . Can patient protect airway? has been reported that family members experience anxiety, depression, and posttraumatic stress disorder. Current research and interventions are locusing on how to improve Assess Oxygenation recognition, prevention, diagnosis, and management. o Decreased oxygen saturation? . Widened A-a gradient? Common ICU Conditions Assess Ventilation Acute Respiratory Failure . Respiratory drive adequate? o Minute ventilation adequate? Acute respiratory failure occurs when a patient cannot ade- . ABG shows hypercapnia? quately oxygenate blood (hlpoxemia) or remove carbon dioxide (hypercapnia) from the blood. History and physical examina- t I G U R E 2 5. Key components of the assessment of acute respiratory failure. tion together with tests such as chest radiograph (Table 52), CT A-a = alveolar-arterial; ABG = arterial blood gas.

Common ICU Conditions Assess Ventilation Acute Respiratory Failure . Respiratory drive adequate? o Minute ventilation adequate? Acute respiratory failure occurs when a patient cannot ade- . ABG shows hypercapnia? quately oxygenate blood (hlpoxemia) or remove carbon dioxide (hypercapnia) from the blood. History and physical examina- t I G U R E 2 5. Key components of the assessment of acute respiratory failure. tion together with tests such as chest radiograph (Table 52), CT A-a = alveolar-arterial; ABG = arterial blood gas. 67