Risks of Transport

Risks of transport are not precisely known. The progression of underlying disease, inadequacy of care delivered during transport, or the physical stress of transport itself can all lead to clinical deterioration of the patient during transport.

The transport environment, given its limited resources and multiple distractions, is bound to be error prone. In a population-based retrospective cohort study of nearly 20,000 air-medical transports, significant adverse events (defined as death, need for major resuscitative measures, hemodynamic deterioration, inadvertent extubation, or respiratory arrest) occurred in 1 in 20 transports. Baseline hemodynamic instability and assisted ventilation before transport and duration of transport were independent predictors of adverse events.¹ A retrospective review of voluntarily reported adverse events, which is likely to underestimate the true incidence, reported 11.3 adverse events occurred per 1000 flights.² The error rate of 1.13% seems low relative to the 2.9% to 16.6% reported incidence of adverse events per hospitalization, but given that the duration of transport is measured in hours, not days, the incidence of adverse events per unit time is quite high.³

The most frequent cause of transport-related adverse events with potential for patient harm is inadequate communication.² Communication errors are widely recognized to be a major preventable cause of morbidity and mortality in medicine in general. Because interfacility transport involves handoffs between at least three care teams, special care must be taken to ensure that critical details are transmitted. Complete documentation of all patient care records must be sent from the referring facility. Referring physicians should directly communicate the following to both the transport team and the accepting physician: (1) patient identification and medical history, (2) interventions performed during initial stabilization and the patient’s response, (3) pertinent physical examination findings, (4) ongoing therapy, and (5) complications that might occur during transport. The transport team must relay this information to the accepting physician, nurse (RN) and respiratory therapist (RT) in addition to information about the patient’s physiology and interventions performed while en route.

The incidence of adverse events in children is somewhat higher, ranging from 1.5% to 2.8% in transports with a specialized pediatric team to 20% to 61% in high-risk patients transported by nonspecialized teams. Adverse events in pediatric transport tend to be more serious. Airway-related events (loss of endotracheal tube, multiple intubation attempts, malposition of endotracheal tube) are by far the most common adverse event in pediatric transport, followed by loss of critical intravenous (IV) access, sustained hypotension, and cardiac arrest.^4–6

Rapid Transfer, Goal-Directed Therapy, and the Golden Hour

Emergency medical services (EMS) and regional flight teams tend to work under the assumption that the time between the moment of injury and arrival at a center capable of delivering definitive care is among the most important determinants of survival. This notion has been taught for 3 decades but is based on little or no evidence and has recently been scrutinized. Time from scene departure to arrival at the hospital was not associated with survival in out-of-hospital cardiac arrest, and transport time including scene time was not associated with survival in trauma.^7,8 At the time the “golden hour” was conceived, prehospital care consisted of providing supplemental oxygen, a fast-moving vehicle, and minimal resuscitation. Under these circumstances, a worse outcome could be expected as prehospital time increased.

Belief in the golden hour may lead to risky behavior. High speeds occasionally result in crashes with injury to EMS providers as well as patients, and EMS have an occupational risk of death similar to that of policemen or firefighters.

There are certainly disease processes—aneurysms requiring neurosurgical intervention, thrombotic events requiring directed thrombolysis, complete transposition of the great arteries requiring urgent atrial septostomy, for example—in which rapid transport to a center that can provide definitive care is the most pressing issue. These are rare in children and, although reasons for interfacility transport of adult patients have not been studied, are likely to represent a small fraction of all critical care adult transports.

In pediatric patients, respiratory failure and shock are the most common reasons for transport. A recent study identified shock in 37% of children transferred to tertiary centers, regardless of reason for referral.⁹ In adults and children, protocolized, aggressive, early therapy of septic shock has proven vastly more effective than any pharmacologic intervention at improving mortality.^10–12

Pediatric protocols recommend aggressive fluid resuscitation, initiation of inotropes, and administration of antibiotics within the first hour after presentation.¹³ The recommended treatments are simple interventions that can be initiated in community emergency departments (EDs) and continued and refined in transport, provided the treating physician and transferring team appreciate the urgent need and are sensitive to the subtle signs of shock in children. Han et al. reported that when community physicians aggressively resuscitated and successfully reversed shock before a transport team arrived, patients had a ninefold increase in their odds of survival.¹¹ These studies defy the popular notion that out-of-hospital stabilization wastes time and delays definitive therapy that should be rendered at the receiving facility.

Although adult guidelines are more relaxed, there are no data to suggest that it is safe to delay goal-directed therapy for transport. In fact, in adults with septic shock, a delay in antibiotic therapy is associated with worse survival, with mortality increasing by 7% for every 30 minutes that passes without delivery of appropriate antibiotic therapy. The golden hour in transport is the time from presentation to initiation of appropriate treatment, treatments that should be initiated at the referring facility and continued and refined by the transport team.¹⁴

Regionalization of Critical Care

Significant advances in therapeutic and diagnostic interventions for critically ill patients have occurred, but often at great cost and limited availability, prompting the need for transport of these patients to tertiary care centers. A recent consensus conference on prioritizing the organization and management of intensive care services in the United States (PrOMIS) suggested that intensive care would be optimally delivered in a tiered regionalized system.¹⁵ Ideally, regionalization would reduce practice variation, improve adherence to best practices, and reduce costs by realizing economies of scale. Regionalization would necessarily result in an increased number of transfers of critically ill patients from lower-volume to higher-volume centers, so the PrOMIS conference proposed that regionalization must be coupled with a regionalized emergency transportation system.

Emergent interfacility transport should occur after initial stabilization and determination by the referring facility that the patient’s needs for care are beyond the scope of local capabilities. In trauma, neonatal intensive care, and pediatric intensive care, the accepting physician serves as an expert who can guide pretransfer stabilization and ensure the safety of transport. Over time, local or low-volume hospitals will have less and less experience with critically ill patients. The transport system may be a useful avenue for education of referring physicians. Receiving centers should have communication centers that facilitate transfers, outreach teams to provide referring facilities with continuing education, and education programs about regional resources and trauma systems.

Out-of-Hospital Transport