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Blood gas temperature correction is an important process to implement when assessing blood gas laboratory values. The laws of physics concerning gas solubility dictate the output values for blood gases. It is incumbent upon the practitioner to interpret these values while considering the physiological environment. This activity reviews blood gas temperature changes, correction equations, how each correction method alters management, and the role of the interprofessional team in blood gas interpretation. Objectives: Outline how temperature changes alter blood gas values. Describe alpha-stat and Ph-stat temperature correction methods and their current applications. Identify current practices relating to blood gas correction. Explain how improved interprofessional communication can augment the success of blood gas temperature correction. Access free multiple choice questions on this topic.

The creation of the first blood gas apparatus can be attributed to John Severinghaus, Leland Clark, and multiple other inventors with their respective contributions. This adjunct to standard care practices revolutionized the assessment of critical patients. Contemporary devices have evolved from the apparatus originally used by Severinghaus, but the techniques underlying blood gas detection are largely unchanged. Notably, modern devices reach temperatures of approximately 37 degrees centigrade. In many cases, this temperature is within the margin of error for an approximation of the patient’s temperature. However, in cases of hyperthermic or hypothermic patients, there must be consideration of the influence of temperature upon the detected partial pressure of oxygen (PO2), the partial pressure of carbon dioxide (PCO2), and pH. In this article, arterial blood gas detection will be described with attention to methods of management as they relate to the temperature correction.[1]

It was common practice to cool blood gas tubes in order to slow leukocyte metabolism, which would result in inflated PCO2 values and an underestimate of PO2 and pH. Cooling is no longer recommended as PVC syringes are widely used, and as the tubes cool, they become more permeable, releasing PO2 and resulting in an underestimate. Instead, practitioners are encouraged to process blood gas samples within 15 minutes for more accurate PO2 results with minor metabolic interference and within 30 minutes for all other desired values. Other influences on blood gas readings that can result in inaccurate findings include capturing an air bubble in the sample, shaking the sample vigorously, drawing from a line containing fluid other than blood, and improper phlebotomy technique.[9]

A laboratory's acquisition of blood samples includes provider order, identification, collection, transportation, and separation/preparation. This is only the preanalytical phase of a blood gas order, and numerous steps are liable to go awry. Using point-of-care testing (POCT) minimizes the number of teams involved. Depending on the situation, the person using POCT may also be the ordering practitioner, thereby closing the feedback loop. Depending on the technology, data may be immediately uploaded to the electronic medical record (EMR), allowing for efficient transmission. Although the process is simplified by eliminating the variable of multiple team members, there are common and potentially devastating errors that can still occur. One of the most impactful mistakes, regardless of the method of testing used, is the misidentification of the patient. This error may be avoided by standard practices akin to time out in the operating room, wherein the patient and correct test are identified prior to drawing the sample. An additional error pertinent to blood gas temperature correction is temperature recording. In order to accurately correct the readings for a patient's temperature, the correct temperature must be taken. The correct temperature method must be recorded at the time of the draw, and this information relayed to the laboratory. The sample should be transported and processed within 15 minutes to 30 minutes, depending on the desired data. The laboratory must have the equipment and availability to process the information. The medical center should have the infrastructure to be able to communicate the findings to the ordering practitioner in a timely manner. Each step of this cascade could be examined for effectiveness. Should any shortcomings be identified, the medical center could implement a plan to address those shortcomings.[9][10]

Each party involved in the hand-off and readback of a blood gas sample provides an opportunity for error. Jacobs et al. intervened by creating a committee to oversee all POCT conducted through their medical institution. Furthermore, after its establishment, the committee continued to intervene once monthly to monitor teams, revealing that particular teams were delinquent in upholding quality standards in regards to POCT. The intervention included a questionnaire to identify deficiencies and a plan for re-training. These same interventions could be effective in blood gas submissions.[10]

Monitoring for blood gas POCT is also covered in Jacobs et al.'s proposal. Monitoring is conducted via monthly investigation of quality indicators involving proficiency testing, maintenance performance, patient identification, alert value confirmations, and quality control performance. In instances of blood gas readings aside from POCT, teams can implement the same protocol, this time involving the multiple teams included in laboratory-processed samples. These measures would ensure higher confidence that testing is being performed correctly. For example, monitoring blood sample labeling or the laboratory's processing time for blood gases could result in upholding a higher standard of patient care and improved patient data.[10]