Mixed Venous Oxygen Saturation in Aeromedical Pre-Hospital Care Post-COVID-19

Aeromedical transport presents unique challenges, as limited but critical care equipment must support a variety of patient scenarios. Clinical judgment and previous statistics are crucial for anticipating potential problems. Mixed venous oxygen saturation (SvO2) can assess impairments in cardiopulmonary circulation, provide information about cellular metabolic demand, and predict poor outcomes. SvO2 lab values can be helpful in the management of intra-atrial balloon pump patients. In the instance of sepsis, SvO2 monitoring could enhance airway and ventilation management. Traumatically injured patients with blood loss could have blood product resuscitation more tightly controlled using SvO2 monitoring. We hypothesize that SvO2 can be an advantageous laboratory value for aeromedical transport, and with this additional information, flight crews can make more informed decisions regarding patient care. We obtained de-identified pre-hospital flight data from a US air ambulance company operating in ten states from 2018–2022. We identified three ICD-10 code categories (traumatic injury, heart failure, and septic shock) in which SvO2 could potentially change patient management in flight. We compared data from pre- and post-COVID-19 periods to assess whether there was an increased need for SvO2. Additionally, we designed a survey for aeromedical transport personnel to gather opinions on SvO2 laboratory value benefits or detractors. The survey questions focused on whether having SvO2 for every flight would change their practice and whether including this value for certain flights or as a standard of care would be appropriate and valuable. We also asked whether they thought the emergence of COVID-19 made SvO2 more helpful. Of the 25,124 completed aeromedical transports throughout the five years, it is estimated that at least 26% of those patients could have potentially benefitted from SvO2 monitoring. A sample population of 3,990 flights were assessed, and 14% of these transports were greater than 1 hour of flight time and required additional actions such as special flight releases and hot or cold refueling with the patient onboard. We have analyzed survey data to identify trends in participants' opinions on SvO2 inclusion in pre-flight laboratory values and how COVID-19 may have influenced its potential for use. 90% of participants supported the inclusion of current SvO2 lab values for transportation. Ultimately, we aim to determine whether SvO2 is worth further investigation as a possible inclusion in standard-of-care guidelines. In conclusion, SvO2 is a powerful tool for predicting outcomes in critically ill patients and can inform pre-flight preparation and in-flight care of patients requiring air ambulance transport. With the development of smaller and lighter technologies, it is possible to evaluate SvO2 intra-flight. Future studies can further characterize the benefits of SvO2 by developing a model to measure patient outcomes in a retrospective study. Our findings can help standardize guidelines for SvO2 utilization and improve patient outcomes in air ambulance transport.