On-Site Hospital Helipads: Resource Document for the NAEMSP Position Paper on On-Site Hospital Helipads

Abstrast

The purpose of this article is to address the question of helipad location for hospitals using helicopter emergency medical services (HEMS). A helipad is defined as off-site, or remote, if a ground ambulance is required for patient transport between the helicopter and the hospital's patient care area. On-site helipads are those for which no ground ambulance transport is required between the hospital and the helicopter. The article describes the attributes of on-site helipads, which include elimination of the inherent risks of additional patient transfers, enhanced availability of emergency medical services (EMS) resources that would otherwise be used for extra transfer, and decreased time to arrival at the receiving treatment site. It is acknowledged that helipad placement decisions are informed by non–patient care issues and a paucity of research. Nevertheless, when the choice is viewed from a patient care perspective, there is a clear preference for on-site helipad location.

Key words:

• helicopter EMS
• helipad
• trauma
• prehospital time
• transport
• patient safety

Introduction

Helicopters are an integral part of most health care systems in the United States, with an estimated 450,000 helicopter transports per year.¹ Although helicopter transports and reimbursement for prehospital care in general make up less than 1% of the cost of health care, a hospital helipad landing zone (hereafter referred to as helipad) can be a significant infrastructure investment on the part of hospitals and also a significant geographic challenge.

The last several years have seen significant—and appropriate—attention to the general topic of helicopter safety. Such efforts have resulted in detailed scientific analysis² that has some relevance to the helipad positioning issue. The available evidence³ supports a conclusion that properly located, constructed, and operated on-site helipads incur no significant risk to surrounding structures or people.

This paper reviews the evidence on helipad location at hospitals served by helicopter emergency medical services (HEMS). Specifically, the paper assesses two arrangements for helipad location: on-site (either ground level or rooftop) and remote. For the purposes of this document, on-site versus remote helipad classification is defined by the need for a ground vehicle transport leg between the hospital and the helipad; remote helipads require a land ambulance to effect the hospital–helicopter transport leg (regardless of the proximity of the helipad location to the hospital campus). This paper is intended to address helipad location at both referring hospitals and receiving centers.

The essential characteristics of the helipad landing zone and the risks and benefits of helicopter transport itself are beyond the purview of this paper. Further details, including the essential features of a helipad, together with sample diagrams as well as related requirements that occur if federal funds are used to construct/modify helipads, have been outlined by the Federal Aviation Administration (FAA).⁴

Discussion

The Maine Study

Though there is little guiding literature directly addressing the subject of helipad placement, a government-sponsored analysis from Maine provides some useful insight. As part of the city planning process pursuant to the bid of a level I trauma center to construct an on-site helipad, the city commissioned a report addressing potential patient care advantages from an on-site helipad; this report (which was not subject to the editorial peer-review process) is available as a public-domain document.³

The Maine project entailed review of a sample of 100 consecutive HEMS transports during 2003–2004, into (n = 99) or out of (n = 1) the trauma center's remote helipad. Clinical and logistics information relevant to these patients was obtained by reviewing records from the HEMS program, the level I center, and patient care reports from the ground emergency medical services (EMS) system that provided transport for the 15-minute ground transport leg between the HEMS helipad and the hospital. The region's HEMS utilization guidelines were consistent with those widely used in the United States and with the National Association of EMS Physicians' (NAEMSP's) recommendations for HEMS use⁵; the sample was thus reasonably representative of HEMS transports to a U.S. trauma center.

The report focused on the issues posed by remote versus on-site helipads, and addressed the potential patient safety/outcome risks incurred by requiring an extra ground transport leg from the remote helipad to the hospital. The two major problems noted in the report were 1) extra time (sometimes exceeding a half-hour) required to effect the ground transport leg and 2) extra patient transfers inherent in the need to load and unload patients from the ground transport vehicle.

In the Maine study, a variety of complications occurred during the transport leg, after the initial transfer of patients from the aircraft to the ground ambulance.³ While causation cannot be proven, it is clear that some complications (e.g., medication infusion depletion, vomiting, laryngeal mask airway failure requiring endotracheal intubation) that occurred during ground transport legs from remote helipads would not have occurred until after hospital arrival (if at all) had an on-site helipad been available. For example, on two occasions transport ventilator batteries failed—a complication known to incur significant clinical risk⁶—leading to changeover to manual ventilation with inherent lessened ventilatory control and, in a case of Neisseria meningitidis sepsis, infectious disease exposure to the transport crew.

The Maine study also addressed the problem of complications occurring during the physical transfer of patients, since remote helipad placement requires an extra transfer. In this study,³ events occurring during the transfer of patients from HEMS to ground ambulance stretchers included respiratory arrest, oxygen desaturation, neurologic deterioration, gastrointestinal hemorrhage, and malfunction of ventilators (apart from battery failure issues noted earlier).

Overall, when all complications occurring during transport from remote helipads to a receiving hospital were considered, the complication rate was 14% (95% confidence interval 8–22%). This calculation does not include patients with acute illness or injury for whom prolonged transport associated with the ground leg posed additional risks due to time criticality of the disease.

Issue 1: Time to Arrival at the Receiving Treatment Site

An extra transport leg incurs, at the minimum, extra out-of-hospital time. Notably, even in situations in which the remote helipad is “close” to the emergency department (ED), the addition of the short ground transport leg incurs time costs that may be significant for some patients. Lerner and Billittier,⁷ in their 2000 study of nearly 400 HEMS-transported patients who underwent a 0.6-mile ambulance transfer from a remote helipad to the ED, noted that the mean time added to transport exceeded 5 minutes. This prolongs transport for patients with multisystem trauma or illnesses (e.g., myocardial infarction, stroke) who need urgent access to time-sensitive interventions.⁸, ⁹, ¹⁰ While it is not easy to pinpoint cause and effect for specific adverse events associated with delays incurred by employing an additional ground transport leg, there can be little argument that patients with acute trauma, coronary syndromes, strokes, or other obviously time-critical diagnoses are better served by minimizing transport times. Prolonged prehospital time due to patient access issues has been highlighted by a 2005 report¹¹ that argued even a few minutes' delay (incurred in getting to patients above the third floor of high-rise buildings) was a sufficient problem to constitute grounds for clinical concern.

In addition to the advantages with getting patients to definitive care more quickly, elimination of unnecessary out-of-hospital time minimizes patient time inside the transport vehicle, in which clinical interventions can be problematic. Tasks ranging from airway management¹², ¹³ to advanced life support interventions¹⁴ to chest compressions for cardiopulmonary resuscitation (CPR)¹⁵, ¹⁶ are more difficult to perform in the out-of-hospital (air or ground) transport vehicle than they are in the controlled setting of the hospital. Optimally functioning prehospital equipment may fail to detect abnormalities (e.g., cardiac dysrhythmias) easily found in the hospital environment.⁶ Furthermore, equipment malfunctions are documented to occur more frequently in the transport setting, and such problems are also more difficult to address outside of the hospital.⁶ This line of reasoning does not mean that transport vehicles are dangerous, but it does mean that extra time spent in the transport setting should be minimized and justifiable.

Issue 2: Improved Availability of Emergency Medical Services Resources

The additional time spent in executing the round-trip ground transport leg also incurs some risk of delaying the HEMS response time for a new request. Because of the logistics involved in secondary movement of patients, especially with high-level interventions such as use of ventilators and chest tubes, significant additional time is incurred in secondary transport regardless of the distance involved. If a flight request comes in while crews are involved with execution of a ground transport leg, or are in a hospital remote from their aircraft, there will be a delay in servicing this request. Thus, the issues relevant to remote placement of a hospital's helipad apply not only to the individual patient undergoing the additional transport leg, but also to other patients who may need time-critical access to HEMS.

The vehicle availability issue is not limited to the air medical resource. In addition to taking the helicopter out of service for a longer period, the ground ambulance used to transport the HEMS patient is unavailable for calls.

Issue 3: Elimination of Inherent Risks of Additional Patient Transfers

Apart from the time issues associated with adding the ground transport leg from the remote helipad, another component of risk is incurred by the extra physical movement of the patient (i.e., jostling while moving into and out of ambulances, as well as movements occurring during the ambulance ride). While patient transfers into and out of vehicles occur every day, and should not be considered cause for unreasonable concern, the fact remains that every physical transfer of a patient is associated with some degree of risk. Elimination of unnecessary transfers is an essential goal in managing seriously ill and injured patients.

Whether the concern is dislodgment of airways, interruption of intravenous (IV) infusions, jostling of fracture sites, or inciting instability in spinal injuries, HEMS patients are particularly likely to be susceptible to transfer-associated complications. HEMS patients are often intubated at the time of transport. One complication reported to be due to moving intubated patients is development of ventilator-associated pneumonia, which appears to be caused by jarring and displacement of ventilator tubes.¹⁷ Additionally, the fact that patients must often be manually ventilated during transfers entails the risk of over- or underventilation. Consistent ventilation synchrony (i.e., matching of assisted breaths with patients' spontaneous breathing efforts) is very difficult to maintain during manual ventilation; asynchrony markedly increases the patient's work of breathing.¹⁸ Other problems with manual ventilation include inconsistent positive pressure and potential for worsening blood oxygenation for a given percentage of inspired oxygen.¹⁸ Attendant changes in blood oxygenation are often sufficiently severe to incur substantial risk of low blood pressure, cardiac dysrhythmia, or both.¹⁹

Other issues may also arise related to ground transport and patient transfers. These risks have been well delineated in the realms of both intra- and interhospital transport, in which the advantages in minimizing patient transfers have been demonstrated. Risks identified in clinical studies²⁰, ²¹, ²² include, but are not limited to, the following: inadvertent discontinuation of blood pressure support drug infusions (with resultant hypotension), loss or infiltration of IV lines, repositioning-associated changes in patient comfort (with associated pain-caused physiologic sequelae), accidental dislodgment of endotracheal tubes, displacement of fractures with associated pain and bleeding, movement of surgical drains, and disconnection of cardiac monitoring leads. Furthermore, even in the absence of any dislodgments or equipment-specific issues, it is known that positional changes tend to effect changes in cardiac output and respiratory mechanics.²³ These movement-associated adverse events, clinically significant in terms of both morbidity and mortality,²⁰ have been shown to occur even when trained personnel are accompanying, and paying close heed to, the patient being transported.²¹

Particularly relevant to the helipad location question are findings that mishaps have been found to occur in as many as a third of transports of critically ill patients in hospital, and that problems tend to occur during patient movement from one stretcher to another.²¹ In addition to intubated patients, pediatric patients appear to be particularly vulnerable to complications during transfer. Problems with oxygenation and ventilation, as well as inadequate fracture immobilization and resultant displacement and pain, have been noteworthy in studies of transfers of pediatric patients.²²

Thus, there are clinically important risks associated with any transfer, whether essential to patient care or as a result of system issues, such as the ground transport leg after remote helipad landing. The risks associated with patient transport increase with the number of transfers, especially in the critically ill. Therefore, elimination of unnecessary transfers is an issue of patient safety. Indeed, it has been estimated that at major hospitals about one patient per month suffers from cardiac arrest or death from (intrahospital) transport-related complications.²⁴ Although most studies on transfer of patients were conducted inside the hospital environment, it is evident that eliminating extra transport legs out of hospital will result in safer, more effective care.

It should be emphasized that current systems using remote helipads are not practicing substandard patient care. Rather, the evolution of the evidence pertinent to helipad location means that on balance, patient interests are better served with on-site helipad location. It is acknowledged that the costs and logistics involved in changing a remote helipad to an on-site location may be prohibitive. Though remote helipads have served many hospitals and patients, evolution to the use of on-site helipads represents a potential mechanism for significantly improving transport efficiency and patient outcomes.

Conclusions

The advantages offered by on-site helipad location include elimination of the inherent risks of additional patient transfers, enhancement of availability of EMS resources that would otherwise be used for the extra transfer, and decreased time to arrival at the receiving treatment site. From these multiple advantages to on-site helipad location, and no medical disadvantages, there is a clear need to move toward helicopter landing areas that are physically on site at referring and receiving institutions. This is particularly important for medical transport systems to consider when building a new helipad.

The NAEMSP position paper on on-site hospital helipads will appear in a future issue of Prehospital Emergency Care.