Pain, high in the sky

Globalization has opened our world for international travel, as well as seeking specialized care far away and its associated medical air transport. More and more patients are air transported by fixed-wing air ambulances each year. Interestingly, even though medical procedures are being performed regularly during flight, it was thus unknown whether pain experience differs during flight, from being with two feet on the ground. Some studies in animal models and humans point to alterations in nociception following changes in environment and altitude. Still, current in-flight anesthetic treatment protocols do not differ between flight and ground-level care.

To verify whether pain perception indeed changes during air-ambulance flights, researchers from the Erlangen-Nuremberg University conducted a study in which sensory and pain perception testing took place in-flight, during several phases of avigation (Prottengeier et al., 2020).

Twenty-five male participants, all crewmembers, participated in the study. Testing was performed just before take-off, right after reaching, and just before descending from cruising altitude, and after touch down. QST consisted of perception thresholds, pain thresholds, and supra-threshold pain stimuli. Thermal, mechanical, and pressure pain QST were performed.

Thermal QST was conducted using Medoc’s TSA-II according to the standardized and validated DFNS (German Research Network on Neuropathic Pain) protocol.

Atmospheric pressure and oxygen saturation were measured during flight. Lowered cabin pressure and light hypoxia was measured in the cabin and on test-subjects at altitude.

Although changes in heat and cold thresholds at altitude were observed, no systematic bias toward a specific direction was noted. The authors conclude that one must be aware of occurring changes in pain experience for patients traveling per fixed-wing air ambulance as these may be prone to fluctuate due to the environmental (noise, humidity, saturation, altitude) influences on a person during flight.

Reference:

Prottengeier, J., Elsner, S., Wehrfritz, A., Moritz, A., Schmidt, J., & Meyer, M. (2020). Nociception testing during fixed-wing ambulance flights. An interventional pilot study on the effects of flight-related environmental changes on the nociception of healthy volunteers. PloS one, 15(2), e0217530.‏

Full-text:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217530