Ira J. Blumen

Factors associated with the safety of EMS helicopters

The accident rate for emergency medical service (EMS) helicopters is thought to be approximately twice the rate for other commercial (Part 135) helicopters. This observation has led to numerous news reports and to the publication of conclusions of a National Transportation Safety Board investigation. The data for these reports come from investigations of EMS helicopter accidents and incidents. The authors surveyed all listed civilian EMS helicopter programs to examine both helicopter ambulance mishaps and the number of safely completed missions. Epidemiological methods were then used to compare the safety records of different groups of EMS helicopters. The single most important factor identified was the number of flights made by the program during the study period: busy programs had an eightfold lower accident rate (P less than .0005) and a three-fold lower total mishap (accidents + incidents) rate (P less than .0005) than less active programs. Programs with the ability to fly under instrument flight rules (IFR) at the pilots discretion had no mishaps (P = .044) during the study period. Multivariate analysis shows this IFR capability to be marginally significant as an independent factor (P = .099).

Flight Physiology: Clinical Considerations

Altitude-related complications and the stresses of flight represent the components of flight physiology. Understanding the complexities associated with patient management relative to barometric pressure changes and hypoxia is of paramount concern to air medical personnel. This article reviews flight physiology as well as appropriate precautions and interventions that must be practiced to provide optimal patient care at various altitudes.

Altitude physiology and the stresses of flight

Associate Professor of Clinical Medicine, Section of Emergency Medicine, Department of Medicine, University of Chicago; Medical / Program Director, University of Chicago Aeromedical Network, University of Chicago Hospitals, Chicago, Ill. Chief Aeromedical Resident, University of Chicago Aeromedical Network; Senior Resident, Section of Emergency Medicine, Department of Medicine, University of Chicago Hospitals, Chicago, III.

Activity-sensing permanent internal pacemaker dysfunction during helicopter aeromedical transport

STUDY OBJECTIVES This study was designed to establish the frequency, magnitude, and possible etiologies of the dysfunction of activity-sensing internal pacemakers during helicopter aeromedical transport. DESIGN Two models of Medtronic Activitrax pacemakers were attached externally to healthy adult volunteers. Each volunteer then was loaded into the helicopter and subjected to a flight sequence. Pacemaker firing rates throughout this sequence were recorded. SETTING On separate days, Aerospatiale Dauphin and Twinstar helicopters completed a total of 23 flights. TYPE OF PARTICIPANTS Four healthy adult volunteers, two men and two women, participated. INTERVENTIONS These included intra- and inter-flight threshold re-programming and external magnet application. RESULTS The average preflight pacemaker rate of 65 beats per minute increased to an average in-flight rate of 105 beats per minute, which resolved to preflight rates on shutdown. This pattern was consistently extinguished with external magnet application. CONCLUSION The effect of rotor motion and flight vibration on the rate-response of the Activitrax pacemaker is both predictable and easily preventable. Possible guidelines for the safe transport of these patients, using pacemaker reprogramming or external magnet application, are examined.

Assessing oxygenation in the transport environment

Abstract The physical signs of hypoxemia often are not seen until profound hypoxemia occurs; therefore a variety of devices commonly are used to assess patient oxygenation. Despite the high reliance on oxygen monitoring equipment when caring for the critically ill, medical personnel often fail to appreciate the advantages and limitations of these devices. In fact, profound hypoxemia can exist in the absence of reliable physical signs. Arterial blood gas measurements, the traditional gold standard for assessing a patients oxygen and acid base status in the hospital setting, only recently have been simplified for transport use. But their inability to perform real-time continuous measurements limits their acceptance into the transport environment. Although used to assess neonatal hypoxemia, the real value of transcutaneous oxygen monitoring may be in avoiding retinal damage as a result of excessive tissue oxygenation. Finally, despite the simplicity, reliability, and popularity of pulse oximeters, few EMS medical personnel really understand how perfusion states, motion, hemoglobinopathies, intravenous dyes, nail polish, and skin color may lead to interpretation errors. This article discusses the limitations of the physical examination, arterial blood gas measurements, transcutaneous monitoring, and pulse oximetry in determining a patients oxygenation status.

53. A Descriptive Analysis of Air Medical Directors in the United States

Purpose : The practice of helicopter emergency medical services is variable in its mission profile, crew configuration, and transport capabilities. We sought to describe the characteristics of physician air medical directors in the United States. Methods : We surveyed medical directors concerning their education, training, transport experience, and roles/responsibilities in critical care air transport programs. Results : Two page surveys were mailed to 281 air medical services. Three programs merged or were dissolved. Data from 122/278 (43.9%) air medical directors were analyzed. One-hundred eleven respondents reported residency training in: Emergency Medicine (EM) 44 (39.6%), Internal Medicine (IM) 18 (16.2%), General Surgery (GS) 18 (16.2%), Family Practice (FP) 12 (10.8%), dual-trained (EM/IM, EM/FP, IM/FP) 11 (9.9%) and others 8 (7.2%). Medical directors’ roles/responsibilities consist, most frequently of: drafting protocols 108 (88.5%), QA/CQI activities 104 (85.3%), crew training 98 (80.3%), and administrative negotiations 95 (77.7%).