Clinical UM Guideline

This document addresses the use of air or water ambulance services. An ambulance is a specially equipped vehicle designed and supplied with materials and devices to provide life-saving and supportive treatments or interventions.

Note: Wheelchair vans or other such vehicles are not equipped as ambulances and are not addressed in this document.

Note: Please see the following related documents for additional information:

• CG-ANC-05 Ambulance Services: Ground; Emergent
• CG-ANC-06 Ambulance Services: Ground; Non-Emergent
• CG-ANC-07 Inpatient Interfacility Transfers

Medically Necessary:

The use of air and water ambulance services is considered medically necessary when all the following criteria are met:

1. The ambulance must have the necessary equipment and supplies to address the needs of the individual; and
2. The individual’s condition must be such that any form of transportation other than by ambulance would be medically contraindicated; and
3. Transportation to the nearest* appropriate facility for treatment of an individual’s illness or injury when either of the following circumstances exists:
   1. Scene of an accident or emergency when there is a medical condition that is life-threatening or first responders (for example, law enforcement officers, emergency medical services members, or fire services members) deem to be life-threatening; or
   2. From one facility to another when the first facility does not have the required services to treat the individual;
      and
4. Either of the following criteria are met:
   1. The individual’s condition is such that the time needed to transport by land poses a threat to the individual’s survival or seriously endangers the individual’s health (for example, ground transportation would take at least 30 minutes longer than air or water transport measured between identification of the need for transport until arrival at the intended destination); or
   2. Significant distances or other obstacles are involved (for example, accessibility based on geography, traffic, or ground weather conditions), such that transport by ground ambulance is not feasible.

*Mileage associated with an air or water ambulance service is considered medically necessary up to the distance required for transport to the nearest appropriate facility.

The use of air and water ambulance services for deceased individuals is considered medically necessary when the above criteria are met and when either of the following is present:

1. The individual was pronounced dead while in route or upon arrival at the hospital or final destination; or
2. The individual was pronounced dead by a legally authorized individual (physician or medical examiner) after the ambulance call was made, but prior to pick-up. In these circumstances the response to call is considered medically necessary.

Not Medically Necessary:

All other uses of air and water ambulance services are considered not medically necessary, including, but not limited to, the following:

1. Transfers from one hospital to another if above criteria not met; or
2. Transfers from a hospital capable of treating an individual to another hospital primarily for the convenience of the individual or the individual’s family or physician; or
3. When land transportation is available and the time required to transport the individual by land does not endanger the individual’s life or health; or
4. Transportation to a facility that is not an acute care hospital, such as a nursing facility, if above criteria are not met; or
5. Transportation to a physician’s office or the individual’s home; or
6. The services are for a transfer of a deceased individual to a funeral home, morgue, or hospital, when the individual was pronounced dead at the scene.

Mileage in excess of the distance from the trip origin to the nearest appropriate facility is considered not medically necessary.

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:

When services are Not Medically Necessary:
For the procedure codes listed above when criteria are not met or for situations designated in the Clinical Indications section as not medically necessary.

When services are also Not Medically Necessary:
For the following procedure code, or when the code describes a procedure designated in the Clinical Indications section as not medically necessary.

Summary

Ambulance services use specially equipped vehicles to provide emergency or non-emergency transport for medical care. Research shows that ambulance transport improves treatment timelines; for instance, those with stroke arriving by ambulance reached care faster and more often within the therapeutic window for intervention. Recent evidence from a 10-year analysis of 1784 interhospital transfers found that ground emergency medical services were most efficient for transfers under 18 miles, while helicopter emergency medical services provided a meaningful time advantage for distances exceeding 30 miles. However, for short or moderate distances, helicopter use conferred minimal or no time savings, and overall transfer durations were similar.

Discussion

An ambulance is a specially equipped vehicle designed and supplied with equipment and supplies to provide life-saving and supportive treatments or interventions. Ambulance transport may involve the movement of an individual to the nearest hospital for treatment of the individual’s illness or injury. While wheelchair vans are specially equipped to accommodate physically challenged individuals, they do not have the proper equipment to qualify as an ambulance. Proper equipment may include ventilation and airway management equipment, cardiac equipment (monitoring and defibrillation), immobilization devices, bandages, communication equipment, obstetrical kits, infection control, injury prevention equipment, vascular access equipment, and medications.

An ambulance may be a ground transportation vehicle, such as a specially equipped truck or van, but may also be a properly equipped aircraft such as a helicopter or airplane, or it may be a specially equipped water craft. Water ambulances are specially equipped boats. This document specifically addresses only air and water transportation-type ambulances.

Use of air and water ambulance services to transport an individual from one facility to another may be appropriate for non-emergent situations when significant distances or other obstacles are involved, such that transport by ground ambulance to the nearest appropriate location is not feasible and other forms of transportation would be medically contraindicated. Transportation may be required to obtain medically necessary diagnostic or therapeutic services when such services are unavailable at the originating facility. For individuals in whom prolonged hospitalization is anticipated, geographical distance may pose a significant barrier to therapeutic recovery or successful integration into post-acute care. Accordingly, prudent clinical judgment may determine that therapeutic services at the destination facility are clinically appropriate and not primarily for the convenience of the individual or the individual’s family or physician. When the nearest appropriate facility is being considered, multiple factors may be taken into consideration, including distance, available diagnostic or therapeutic services, and whether the facility is willing and able to accommodate transfer.

In 2021, the American College of Emergency Physicians (ACEP) defined an emergency service as “any health care service provided to evaluate and/or treat any medical condition such that a prudent layperson possessing an average knowledge of medicine and health, believes that immediate unscheduled medical care is required.” The absence of immediate medical attention could result in:

1. Placing the physical or mental health of the individual afflicted with such condition or, with respect to a pregnant person, the health of the individual or the unborn child, in serious jeopardy; or
2. Serious impairment to such individual's bodily functions; or
3. Serious dysfunction of any bodily organ or part of such individual.

Examples of medical emergencies may include illness or injury such as severe chest pains that might indicate a heart attack, slurred speech or weakness that might indicate a stroke, fracture, hemorrhaging, poisoning, major burns, loss of consciousness or respiratory accidents, convulsions, shock and other acute conditions.

The Medicare Benefit Policy Manual (2018) section addressing time needed for ground transportation (10.4.3) states the following:

Differing Statewide Emergency Medical Services (EMS) systems determine the amount and level of basic and advanced life support ground transportation available. However, there are very limited emergency cases where ground transportation is available but the time required to transport the patient by ground as opposed to air endangers the beneficiary’s life or health. As a general guideline, when it would take a ground ambulance 30-60 minutes or more to transport a beneficiary whose medical condition at the time of pick-up required immediate and rapid transport due to the nature and/or severity of the beneficiary’s illness/injury, A/B MACs (A) and (B) should consider air transportation to be appropriate.

Time can be a key consideration to distinguish the need for ground transportation from the need for air transportation. Air transportation may be considered medically necessary if the total time between identification of the need for medical transportation and arrival at the treatment facility would be 30 or more minutes longer for ground transportation than for air transportation.

In mathematical terms:

If          X = total time (in minutes) for transfer by ground
And     Y = total time (in minutes) for transfer by air
Then if X > (Y + 30), air transportation may be considered necessary.

An important time consideration is the fact that it may take a significant amount of time to assemble an air transport team and to transport the individual from an emergency department to an airport or heliport to begin travel to the destination.

A 2020 retrospective study by Stewart and colleagues compared the outcomes of transport between helicopter transport and ground transport for inter-facility transfer of persons with trauma to tertiary trauma centers. Looking at the records of 9880 people who had been initially seen at a non-tertiary trauma center, but were then transferred to a tertiary trauma center, the authors reported on mortality at 72 hours and within the first 2 weeks after arriving at the tertiary trauma center. For those transferred by helicopter, the mean distance between the facilities was 96.7 miles with a mean distance of 69.9 miles for those transferred by ground ambulance. The helicopter transport group showed a decreased 72-hour mortality only for the individuals transferred less than 90 miles. There were no significant differences in mortality for helicopter transport greater than 90 miles, and no significant differences in mortality at 2 weeks for either transport modality.

In 2021, Kunte and colleagues reported on whether air or ground transport led to faster delivery times in interhospital transfer and direct-from-scene transfer of individuals with ischemic stroke to a comprehensive stroke center. In this retrospective review, there were four cohorts: transfer air (n=47), transfer ground (n=68), scene air (n=40) and scene ground (n=50). Three time periods were looked at within the transport process: alarm to emergency medical services (EMS) arrival, EMS arrival to EMS departure, and EMS departure to comprehensive stroke center arrival. Median alarm to EMS arrival time was 27.5 minutes for transfer air, 15.5 minutes for transfer ground, 22 minutes for scene air, and 10 minutes for scene ground. Total on scene time was represented by EMS arrival to EMS departure. Median EMS arrival to EMS departure time was 13 minutes for transfer air, 14 minutes for transfer ground, 7.5 minutes for scene air, and 12 minutes for scene ground. In order to evaluate EMS transfer time not associated with actual travel time, the authors measured the amount of time it took EMS to respond to alarms and prepare the individual for transfer. Those in the transfer cohort had a median alarm to EMS departure of 39 minutes versus 31 minutes for those in the scene cohort. Also in the transfer cohort, transfer air had a median alarm to EMS departure of 44 minutes versus 36 minutes for transfer ground. For those being transported from the scene, scene air median alarm to EMS departure time was 37.5 minutes compared to 25 minutes for scene ground noting air transport had longer EMS time before departure compared to ground transport. Modified Rankin score was used at 90 days after treatment to quantify functional outcomes. There were no significant differences in scores between the groups. The authors did not report whether outcomes were improved. In transporting individuals either between facilities or from scenes, some variables cannot be accounted for such as weather and traffic at the time of transfer.

A 2022 retrospective study by Joseph and colleagues reported outcomes of critically ill children who were transferred from one facility to a specialized pediatric hospital. The outcomes were compared for those who traveled via helicopter to those who traveled via ground ambulance. In order to limit indication bias, the analysis was limited to only those for whom a helicopter was initially requested by the receiving facility. Primary outcome was in-hospital mortality. Secondary outcomes included hospital length of stay, mode of transport, and transport times. The cohort included 1186 children, 1044 who ultimately traveled by helicopter and 142 who ultimately traveled by ground ambulance (not related to clinical factors). The mean total travel time for helicopter transport was 143 minutes and the ground ambulance time was 289 minutes. In-hospital mortality was 63 individuals (6.0%) for those transferred by helicopter and 10 individuals (7.0%) for those transferred by ground ambulance. Hospital length of stay was 4 days for those transferred by helicopter and 5 days for those who traveled by ground ambulance. In this retrospective cohort study the travel times were shorter for those who traveled via helicopter compared to ground ambulance, but the shorter travel times were not associated with statistically significant differences in mortality or hospital length of stay.

Elkbuli and colleagues (2022) also reported on a retrospective cohort study in which they analyzed outcomes for children and adults transported by helicopter compared to those transported by ground ambulance. The primary outcome was the raw and adjusted mortality adjusted for potential demographic and comorbid variables. These variables included age, race, ethnicity, comorbid conditions, mechanism of injury (only blunt and penetrating injuries were included), injury severity score, Glasgow coma score, revised trauma score and transport time. There were 12,633 individuals transferred during the study period (10,656 [84.4%] via ground ambulance and 1977 [15.6%] via helicopter). In the ground ambulance cohort, there were 307 (2.88%) deaths, the mean injury severity score was 9.29, and the mean revised trauma score was 7.6. There were 9969 participants (93.6%) with blunt trauma. Mean total transport time from the field to the trauma center was 39.45 minutes. Intensive care unit stay was 2.30 days, and the mean Glasgow coma score was 14.30. In the helicopter transport there were 134 (6.78%) deaths, the mean injury severity score was 11.73, and the mean revised trauma score was 7.12. There were 1560 participants (78.9%) with blunt injury. The mean total transport time from the field to the trauma center was 47.29 minutes. Intensive care unit stay was 4.19 days, and the mean Glasgow coma score was 13.24. After controlling for defined covariates, the odds of mortality were 16.4% greater for those transported by ground ambulance compared to those transported by helicopter (adjusted odds ratio [aOR], 1.164, 95% confidence interval [CI], 0.814-1.665). After adjusting for transit time in addition to the defined covariates, the individuals transported by ground ambulance had a 16.6% greater odds of mortality compared to the individuals transported by helicopter (aOR, 1.166, 95% CI, 0.815-1.668). The data in this study was from one single trauma center. Factors such as topography and weather at the time of transport may have affected the choice of transportation mode. The authors acknowledge that they could not control for differences in prehospital care.

A 2025 retrospective clinical cohort study by Lichtenberger analyzed 1784 emergency interhospital transfers. There were 1009 transfers done via helicopter and 775 transfers done via ground ambulance. The authors compared efficiency of these two transfer modes by evaluating time from dispatch to collection point, transport duration, total time from transport request to arrival at the target location, and total occupancy time. Overall, the mean collection duration (that is, the time from dispatch until handover at the transferring facility) was 13.0 minutes for helicopter and 12.1 minutes for ground ambulance. In terms of transport duration, after picking up the member, helicopter transfer reached the destination hospital in 21.9 minutes compared to 25.6 minutes on average for ground ambulance. Overall transfer duration from dispatch to handover via helicopter averaged 57.5 minutes compared to 54.2 minutes for ground ambulance. The total occupancy time was 74.3 minutes for helicopter and 70.5 minutes for ground ambulance. When distance was taken into account, ground transport was more efficient for transfers under 30 km (about 19 miles), while helicopter transport offered meaningful time savings, approximately 30 minutes, only for transfers exceeding 50 km (about 31 miles).

Peer Reviewed Publications:

1. Elkbuli A, Dowd B, Sanchez C, et al. Emergency medical service transport time and trauma outcomes at an urban level 1 trauma center: evaluation of prehospital emergency medical service response. Am Surg. 2022; 88(6);1090-1096.
2. Funder KS, Rasmussen LS, Lohse N, et al. The impact of a physician-staffed helicopter on outcome in patients admitted to a stroke unit: a prospective observational study. Scand J Trauma Resusc Emerg Med. 2017; 25(1):18.
3. Galvagno SM Jr, Haut ER, Zafar SN, et al. Association between helicopter vs ground emergency medical services and survival for adults with major trauma. JAMA. 2012; 307(15):1602-1610.
4. Joseph AM, Horvat CM, Evans IV, et al. Helicopter versus ground ambulance transport for interfacility transfer of critically ill children. Am J Emerg Med. 2022; 61:44-51.
5. Kunte SA, Anderson D, Brown-Espaillat K, Froehler MT. Total transfer time for ground vs. air transport for interhospital and scene transfers of acute stroke patients. J Stroke Cerebrovasc Dis. 2021; 30(6):105704.
6. Lichtenberger PM, Peer MF, Lindtner RA, et al. Helicopter vs. ground-based transfer for emergency interhospital transportation: a time and cost-efficiency analysis across varying transfer distances. Injury. 2025; 56(7):112359.
7. Nolan B, Haas B, Tien H, et al. Causes of delay during interfacility transports of injured patients transported by air ambulance. Prehosp Emerg Care. 2020; 24(5):625-633.
8. Stewart K, Garwe T, Oluborode B, et al. Association of interfacility helicopter versus ground ambulance transport and in-hospital mortality among trauma patients. Prehosp Emerg Care. 2021; 25(5):620-628.

Government Agency, Medical Society, and Other Authoritative Publications:

1. American College of Emergency Physicians. Policy Statements. Available at: https://www.acep.org/patient-care/policy-statements. Accessed on October 02, 2025.
   • Appropriate and Safe Utilization of Helicopter Emergency Medical Services (June 2024)
   • Appropriate Interfacility Patient Transfer (January 2022)
   • Definition of an Emergency Service (January 2021)
   • Emergency Medical Services Interfaces with Health Care Systems (June 2024)
2. American College of Surgeons; Committee on Trauma; American College of Emergency Physicians; National Association of EMS Physicians; Pediatric Equipment Guidelines Committee; American Academy of Pediatrics. Equipment for ambulances. Bull Am Coll Surg. 2009; 94(7):23-29.
3. Doucet J, Bulger E, Sanddal N, et al. Appropriate use of helicopter emergency medical services for transport of trauma patients: guidelines from the Emergency Medical System Subcommittee, Committee on Trauma, American College of Surgeons. J Trauma Acute Care Surg. 2013; 75(4):734-741.
4. Lyng J, Adelgais K, Alter R, et al. Recommended essential equipment for basic life support and advanced life support ground ambulances 2020: a Joint Position Statement. Prehosp Emerg Care. 2021; 25(3):451-459.
5. Medicare Benefit Policy Manual. Chapter 10 - Ambulance Services. April 17, 2025. Available at: https://www.cms.gov/Regulations-and-Guidance/Guidance/Manuals/Downloads/bp102c10.pdf. Accessed on October 02, 2025.
6. Thomson DP, Thomas SH; 2002-2003 Air Medical Services Committee of the National Association of EMS Physicians. Guidelines for air medical dispatch. Prehosp Emerg Care. 2007 (2):265-271.

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Federal and State law, as well as contract language, and Medical Policy take precedence over Clinical UM Guidelines. We reserve the right to review and update Clinical UM Guidelines periodically. Clinical guidelines approved by the Medical Policy & Technology Assessment Committee are available for general adoption by plans or lines of business for consistent review of the medical necessity of services related to the clinical guideline when the plan performs utilization review for the subject. Due to variances in utilization patterns, each plan may choose whether to adopt a particular Clinical UM Guideline. To determine if review is required for this Clinical UM Guideline, please contact the customer service number on the member's card.

Alternatively, commercial or FEP plans or lines of business which determine there is not a need to adopt the guideline to review services generally across all providers delivering services to Plan’s or line of business’s members may instead use the clinical guideline for provider education and/or to review the medical necessity of services for any provider who has been notified that his/her/its claims will be reviewed for medical necessity due to billing practices or claims that are not consistent with other providers, in terms of frequency or in some other manner.

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