Is aeromedical transport of patients during acute myocardial infarction safe?

Aeromedical Transportation of the Critically Ill Cardiac Patient: In-flight Considerations and Management

The aeromedical transportation (AMT) of critically ill cardiac patients can enable access to advanced specialized medical attention, or provide improved care for operational, psychosocial, political, or economic reasons. However, AMT is a complex undertaking necessitating extensive clinical, operational, administrative, and logistical planning to ensure that the patient receives an equivalent level of critical care monitoring and management in the air as on the ground. This paper is the second of a 2-part series. Part 1 focused on the preflight planning and preparation for critically ill cardiac patients during AMT aboard commercial platforms, while this current part aims to provide an overview of in-flight considerations for the same population.

Severity of cardiovascular disease patients transported by air ambulance

INTRODUCTION

Although helicopters have been used in an air ambulance system for the past decade in Japan, the appropriate selection of patients for this transport mode has not been investigated. The present study investigates which patients could potentially benefit the most from helicopter emergency medical service (HEMS).

METHODS

We investigated the extent of circulatory and respiratory support required in the intensive care unit (ICU) and ultimate outcomes of 2340 patients with cardiovascular disease admitted to 1 institution between October 2001 and December 2009. Two hundred and seventy were transported by HEMS (HEMS group), and 2070 were transported by other means (non-HEMS group).

RESULTS

Temporary cardiac pacing, ventilator management, intra-aortic balloon pumping, percutaneous cardiopulmonary support, electrical defibrillation, and therapeutic hypothermia were more frequently required by patients in the HEMS group vs. the non-HEMS group (10.4%, 28.1%, 17.0%, 5.2%, 10.0% and 3.4% vs. 8%, 17.9%, 10.9%, 2.3%, 4.5% and 0.4%, respectively). The mortality rate was higher in the HEMS group than in the non-HEMS group in the ICU (9.6% vs. 5.3%).

CONCLUSION

Disease was more clinically severe and the outcome was poorer among patients with cardiovascular diseases transported by HEMS than by other means.

Use of an air ambulance system improves time to treatment of patients with acute myocardial infarction

OBJECTIVE

The aim of this study was to clarify whether a helicopter ambulance system (doctor helicopter system; DHS) could shorten the time interval to coronary intervention in the treatment of patients with acute myocardial infarction (AMI), in comparison with ground ambulance (GA).

METHODS

The time from the emergency call to coronary angiography (CAG time) or to percutaneous coronary intervention (PCI time), and the inhospital outcome were evaluated in 76 AMI patients. Twenty patients were transported by DHS, and the other 56 were by GA.

RESULTS

Both CAG time and PCI time were significantly shorter in the DHS (98.8+/-29.2 min, and 169.6+/-57.4 min) than those of the GA (126.6+/-48.7 min, and 203.2+/-57.0 min; p<0.05) group. Inhospital mortality was lower in the DHS (5.0%) versus the GA (10.7%) group.

CONCLUSION

Use of DHS shortened the time interval to coronary intervention and also improved the inhospital prognosis of AMI patients.

Critical care transport: outcome evaluation after interfacility transfer and hospitalization

STUDY OBJECTIVE

To test the hypothesis that interfacility transfer is not associated with increased mortality, duration of stay, or readmission within 7 days.

METHODS

We matched 3,298 patients who were hospitalized for chest pain or related complaints in Kaiser Permanente medical centers after transfer from the emergency department of a nonplan hospital (transported patients) with 3,298 patients of the same gender and age (+/-5 years) and with the same principal diagnosis who were hospitalized within 6 months without transfer in the same Kaiser Permanente medical center (directly admitted patients). Patients were compared in terms of outcome measures: in-hospital deaths, continued care in another facility, readmission within 7 days, in-patient length of stay (LOS), and LOS in special care units.

RESULTS

The adjusted odds ratios for in-hospital mortality and readmission within 7 days were 1.0 (95% confidence interval,.8 to 1.4) and.9 (95% confidence interval,.7 to 1.2), respectively. The adjusted mean difference in LOS was -.1 days (95% confidence interval, -.2 to.1). Transported and directly admitted cardiac patients were also compared for all examined outcome measures at each of 10 medical centers. At a few medical centers, we observed significant difference in LOS, special care LOS, and continued care in another facility. However, all these differences were small, and most were probably random errors.

CONCLUSION

Conservative patient selection criteria, pretransfer stabilization, and the use of appropriate equipment and medical personnel have resulted in the interfacility transfer program's achieving its goal of transferring high-risk patients without adverse impact on clinical outcomes or resource use.

Adverse events during interfacility transfers by ground advanced life support services

OBJECTIVE

To identify risk factors for adverse events that occur during interfacility transfers by advanced life support (ALS).

DESIGN

A four-year, retrospective, case series.

SETTING

Three ALS units in a rural/suburban emergency medical services (EMS) system.

PARTICIPANTS

351 transports to or from twelve acute care facilities; two patients records could not be located.

INTERVENTIONS

Patients were classified by illness/injury, transporting staff, and ongoing therapy; these were correlated with frequency of ALS intervention and patient deterioration.

RESULTS

During the study period, the number of transfers as a percentage of total calls (1.1%-5.2%) rose consistently. There were 11 illness/injury categories; the largest was cardiac (44%, 154 patients). Hospital staff accompanied the patient in 15% (52). Advanced life support (ALS) therapy was required in 4.9% (17): one monitored cardiac arrest was defibrillated successfully, 13 patients required unanticipated medication therapy, and three were noted to have clinical deterioration en route. The upper 95% confidence limit for cardiac arrest is 12.9/1,000 transfers or 20.8/1,000 hours. Patient deterioration and the need for ALS intervention were associated with the presence of medication infusions (p < .05), but not with hospital staff (p > .40).

CONCLUSIONS

Interfacility transfers of a heterogeneous group of patients in this series involve a low risk of cardiac arrest. Patients with medication infusions are at higher risk of deterioration and more frequently require ALS intervention en route. The presence of hospital staff had no measurable effect. These findings have implications for the development of ALS transfer protocols.