Helicopter Transports Research Articles

Use of the esophageal stethoscope in pediatric transports

Monitoring cardiac and respiratory function during helicopter transports can be difficult, so the authors devised a study of the esophageal stethoscope for pediatric patients. The study was conducted at Pediflite in Tennessee, which transports between 250 to 300 pediatric patients every year. A disposable esophageal stethoscope was used as an adjunct to other monitoring systems in intubated patients. Prior to transport, the stethoscope was placed orally by the respiratory therapist and advanced to the point where heart sounds are heard best, at which point breath sounds can also be heard clearly. The device's ear piece easily fit under the crew member's headphones, which block helicopter noise. Three sizes of stethoscope are available: a 6 French for patients 1 day to 4 years old, a 9 French for those 4 to 12 years old, and an 18 French for patients 12 years of age or older. The esophageal stethoscope was used in 55 patients ranging in age from newborn to 18 years. Eighteen of 55 (33%) had multiple trauma or closed head injury, and 14 of 55 (25%) suffered respiratory failure. The esophageal stethoscope proved to be easy to place, had a low risk of complications and allowed continuous access to breath sounds. In addition, the ability to hear heart tones was minimally affected by noise or vibration. Due to its ability to continuously monitor breath sounds, endotracheal tube obstruction or displacement can be rapidly detected by the esophageal stethoscope. Also, if there is failure of the cardiopulmonary monitor, heart sounds can be continuously monitored. The esophageal stethoscope is a simple but potentially valuable tool in pediatric and neonatal transports for monitoring respiratory and cardiac status.

Circadian variation in the time of request for helicopter transport of cardiac patients

The literature has demonstrated circadian rhythms in the occurrence of nonfatal myocardial infarction, ischemia, and sudden death. We hypothesized that requests for helicopter transport of acutely ill cardiac patients followed a similar circadian pattern and differed significantly from requests for helicopter transport of other categories of patients. Prospective study of requests for helicopter transport of 1,128 consecutive air medically transported patients over a 24-month period. One tertiary-care teaching hospital. The periodic structure of the time distribution of cardiac requests for helicopter transport was examined with a two-harmonic regression analysis using a 24-hour period of oscillation. Seven hundred eighty-seven cardiac and 315 noncardiac patients could be evaluated. The times of requests for helicopter transport were tabulated into hourly intervals. Cardiac-related requests for helicopter transport were significantly different from noncardiac-related requests for helicopter transports (P less than .009 by Wilcoxon rank sum test, P less than .032 by Kolmogorov-Smirnov test). The regression model for cardiac requests for helicopter transport was also significant (P less than .0001, R2 = .81) with increasing requests for helicopter transport from 6:00 AM until 12:00 noon. The time distribution of requests for helicopter transport for cardiac patients demonstrates a striking circadian variation not observed in noncardiac patients. This observation strengthens mechanistic inferences from studies of circadian variation and suggests a "morning-loaded" staffing pattern for air medical services predominantly transporting cardiac patients.

Pacing hazards in helicopter aeromedical transport

A 62-year-old man with third-degree atrioventricular block and hemodynamically unstable ventricular tachycardia had a cardiac arrest during helicopter transport to a specialized cardiac care unit. Before transport, his ventricular tachycardia had been successfully terminated by a rapid overdrive pacing technique. The failure of “burst suppression” and the absence of pacer spike artifact on the electrocardiographic monitor raise questions about the potential hazards of using various pacing techniques during helicopter transports. Most significantly, this case points to the possibility of interference by exogenous electromagnetic signals in the medical compartment of the helicopter.

Emergency air transport of pregnant patients: The national experience

There is considerable debate as to the appropriate role of helicopter transfer of sick patients. 1 The debate over helicopter transfer of high-risk obstetric patients is even more intense. There is clear evidence that high-risk neonates are more likely to survive when they are delivered in a perinatal center compared with local delivery followed by transfer. 2–5 On the other hand, there is concern that inflight delivery entails “extreme risks, both to, mother and child.” 6 In spite of this debate, there has been little research into the frequency of delivery during transport to a hospital or into the mortality associated with such a delivery. A study involving a single center suggests that the incidence of inflight delivery is very low. 7 We contacted all American Society of Hospital-Based Emergency Air Medical Services (ASHBEAMS) member air ambulance programs to determine the national statistics for in-flight delivery and associated perinatal mortality. We found no instances of inflight delivery in 357 helicopter transports; 315 of these women were in active labor at the time of transport and 72 were in the accelerated phase of labor. There is evidence that these flights were screened for safety. Airplane flights generally took more time than helicopter flights (P <.05), and there was one in-flight delivery during 88 airplane transfers. Also presented are additional data that suggest in utero transport of high-risk fetuses to a perinatal center by helicopter is cost effective.