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Chloroprocaine is an ester class local anesthetic and is indicated for neuraxial anesthesia (caudal, epidural, and spinal) and peripheral nerve blocks and obstetric anesthesia (pudendal and paracervical blocks). Due to its short duration, it has been used in test doses to evaluate the function of peripheral nerve and epidural catheters. This activity reviews the mechanism of action, adverse event profile, toxicity, dosing, pharmacodynamics, and monitoring of chloroprocaine, pertinent for interprofessional team members where patient care requires local anesthesia that would be met using chloroprocaine. Objectives: Identify the approved and off-label indications for chloroprocaine. Summarize the mechanism of action of chloroprocaine. Outline the necessary monitoring of chloroprocaine. Describe the importance of interprofessional team members to improve patient outcomes in patients receiving chloroprocaine for local anesthesia. Access free multiple choice questions on this topic.

Local anesthetic systemic toxicity (LAST) refers to local anesthetics reaching toxic plasma levels. Initial signs of LAST are tinnitus, perioral numbness, and metallic taste. Classically, LAST progresses from central nervous system excitation (anxiety, muscle twitching, seizures) to depression (sleepiness, loss of consciousness, and respiratory depression) followed by cardiac excitation (tachycardia, hypertension) and finally depression (bradycardia, hypotension, arrhythmias, asystole).[29][30][31] However, the classic presentation is not always seen, and initial symptoms can be quite delayed.[29][32][33] Chloroprocaine doses greater than 11 mg/kg may cause LAST. Please note that LAST has been reported with local anesthetic doses below the maximum recommended dose.[34] Due to its rapid metabolism, the incidence of LAST with chloroprocaine is extremely low. Most case reports of LAST involve administering local anesthetics with a much longer duration of action than chloroprocaine.[29][32] Self-limited 30-second wide complex bradycardia and 40-second self-limited seizure activity have been described after chloroprocaine administration to infants.[35][36][35] Dizziness, tinnitus, metallic taste, nausea, and narrow complex bradycardia have been described in adult patients undergoing intravenous regional anesthesia with chloroprocaine.[37] No long-term morbidity or mortality has been described after chloroprocaine administration.[35][36][37] Careful attention to the prevention of overdose is necessary, with monitoring of the cardiovascular system and level of consciousness following each injection. If overdose is suspected, full hemodynamic support may be required. Benzodiazepines are the preferred treatment for seizures. Airway management for local anesthetic toxicity may range from supplemental oxygen to assisted ventilation to initiation of invasive airway devices and positive pressure ventilation. Critical differences in local anesthetic-induced cardiac arrest treatment include reduced doses of epinephrine (<1mcg/kg) and avoidance of vasopressin, calcium channel blocks, beta-blockers, or other local anesthetics. Dosing is 100 ml (or 1.5ml/kg for patients less than 70kg) 20% lipid emulsion given as a bolus followed by infusion is the treatment of choice for LAST.[38]

Bupivacaine is the most commonly used local anesthetic for spinal anesthesia. Bupivacaine has a long history of safe use, a low incidence of transient neurologic symptoms (post-spinal temporary radiating pain down the buttock and thighs), and it produces a reliable block.[39] The downside of bupivacaine is its long duration of action, up to 240 to 380 minutes.[40] Spinal chloroprocaine is an intriguing alternative to bupivacaine for short procedures (less than 60 minutes). The incidence of transient neurologic symptoms with spinal chloroprocaine is less than spinal lidocaine and equivalent to spinal bupivacaine.[19][41] Spinal chloroprocaine facilitates a shorter time to resolution of motor block, resolution of sensory block, first micturition, first ambulation, and discharge readiness, compared to bupivacaine and lidocaine.[17][40][42][43][44][45][46] In a randomized trial that included 50 patients having knee arthroscopy, spinal chloroprocaine was associated with lower costs than general anesthesia.[47] Multiple outcome studies involving spinal chloroprocaine are currently underway. Extrapolation of current studies involving spinal chloroprocaine suggests spinal chloroprocaine will become more common over the next decade. Intraperitoneal chloroprocaine has been used off-label to provide adjunctive anesthesia for parturients undergoing cesarean delivery under the neuraxial block. In one case series, 32 patients were administered intraperitoneal chloroprocaine as part of a multimodal approach to avoiding general anesthesia when there was an imperfect neuraxial blockade.[48] Despite patients being administered a mean dose of 11.8 mg/kg, no clinical signs of local anesthetic toxicity were observed. Epidural chloroprocaine is commonly used in the obstetric setting to provide rapid onset anesthesia for emergent cesarean delivery when an epidural catheter is in place. Chloroprocaine can be rapidly administered in large doses to provide rapid onset anesthesia without risking maternal or fetal systemic toxicity. The half-life of chloroprocaine in maternal and fetal plasma is 11.2 seconds and 15.4 seconds, respectively.[4] Due to its rapid metabolism, toxic concentrations of chloroprocaine are difficult to achieve.

Epidural chloroprocaine is commonly used in the obstetric setting to provide rapid onset anesthesia for emergent cesarean delivery when an epidural catheter is in place. Chloroprocaine can be rapidly administered in large doses to provide rapid onset anesthesia without risking maternal or fetal systemic toxicity. The half-life of chloroprocaine in maternal and fetal plasma is 11.2 seconds and 15.4 seconds, respectively.[4] Due to its rapid metabolism, toxic concentrations of chloroprocaine are difficult to achieve. While LAST is quite unlikely with chloroprocaine due to its rapid metabolism, vigilance for signs and symptoms of LAST is always recommended. Management of chloroprocaine-related toxicity (LAST) includes prompt recognition of the signs and symptoms and an interprofessional team to manage the potential consequences. LAST is an emergency condition that requires the full attention of nurses, technicians, and clinicians to maintain the airway and treat neurologic and cardiac complications.