A second analysis of patients with decompression illness transported via physician-staffed emergency helicopters.

Dear Editor,

There have been few reports investigating the effects of air transportation on patients with decompression illness (DCI).[1234] Following a previous report,[5] we retrospectively investigated the influence of air transportation on patients with DCI transported through physician-staffed emergency helicopters. A medical chart review was retrospectively performed in all patients with DCI transported through physician-staffed emergency helicopters between March 2004 and March 2015, including an analysis of previous data.[1] The exclusion criterion was cardiopulmonary arrest on surfacing. During the investigation period, 54 patients with DCI were transported through physician-staffed emergency helicopters. Of these patients, 11 experienced cardiopulmonary arrest on surfacing after diving complicated by drowning. Excluding these cases, a total of 43 patients were treated as subjects. Concerning the background characteristics of the subjects, male (n = 31) and middle-aged subjects (average 43.7 ± 1.6 years old) were predominant. The number of patients who suddenly surfaced was 27/43 (62.7%). All patients underwent oxygen therapy during flight, and all but one patient received the administration of lactate ringer fluid. The altitude of all flights was under 300 m above sea level. Concerning the changes in vital signs, there were no significant differences between the values obtained before and after the flight for blood pressure (123.1 ± 2.9 vs. 119.6 ± 2.7 mmHg) and heart rate (87.6 ± 2.2 vs. 88.0 ± 2.4 beats/min). The Glasgow Coma Scale (GCS) score decreased after the flight. Six patients underwent tracheal intubation under the use of sedatives and muscle relaxants to secure the airway or support the respiratory function. After excluding these six cases, there were no significant differences between the values obtained before and after the flight for GCS (14.3 ± 0.2 vs. 14.2 ± 0.3). Concerning the SpO2, statistically significant improvements were noted after the flight (96.9% ±0.6% vs. 98.3% ±0.4%). Accordingly, our second analysis also supported the previous hypothesis that improvements in the subjective symptoms and/or SpO2 of patients with DCI are observed when the patient is transported through helicopter in flights traveling at altitudes of less than 300 m with the administration of oxygen and fluids.[5]

Financial support and sponsorship

Youichi Yanagawa receives a research fund from Ministry of Education, Culture, Sports, Science, and Technology (MEXT)-supported program for the strategic research foundation at private universities, 2015–2019, concerning the constitution of total researching system for comprehensive disaster, medical management, corresponding to wide-scale disaster.

Conflicts of interest

There are no conflicts of interest.