Transporting COVID-19 Patients On Non-Invasive Ventilation Support Via Emergency Medical Service Units

Last Updated: March 4, 2021

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This Briefing Note was completed by the Evidence Synthesis Unit (Research, Analysis and Evaluation Branch, Ministry of Health) in collaboration with a member of the COVID-19 Evidence Synthesis Network.


To summarize the evidence on whether it is safe to transport suspected or confirmed COVID-19 patients who require non-invasive ventilation (NIV) support via standardly equipped emergency medical services (EMS) units.

*The full version of the Briefing Note including the Appendix can be accessed in the PDF file at the top of the page*

Key Findings

Limited information was identified on land ambulances. Information on air ambulances was included, but it is unclear if all these findings can be applied to land ambulances.

Implementation Implications

Extreme caution is recommended if the decision is made to use NIV on suspected or confirmed COVID-19 patients in ambulances. Contact, droplet, and airborne precautions are required in an effort to minimize infection transmission. Clear standard operating procedures and routine scenario-based training of EMS providers can help reduce some of the risks.

Context and Terminology

Emergency medical services (EMS) play a vital role in responding to requests for assistance, triaging patients, and providing emergency medical treatment and transport for ill persons, including suspected or confirmed COVID-19 patients. However, unlike patient care in the controlled environment of a health care facility, care and transports by EMS present unique challenges because of the nature of the setting, proximity to patients in an enclosed space during transport, limited airflow, limited information about their patients, frequent need for rapid medical decision-making, and a varying range of patient acuity and jurisdictional health care resources. EMS also face significant risk of virus transmission during aerosol-generating procedures (AGPs), such as airway management and non-invasive ventilation (NIV). For example, a US study reported that EMS personnel are at a higher risk of dying from COVID-19 than other health care or emergency services professionals. The study estimated the number of EMS personnel COVID-19-related deaths is about three times higher than nurses and about five times higher than physicians.

  • NIV refers to the administration of mechanical ventilation without using an invasive artificial airway (e.g., endotracheal or tracheostomy tube). NIV may be delivered by means of positive-pressure and negative-pressure techniques: with the former, positive pressure is applied to the airway to inflate the lungs directly (e.g., bilevel and continuous positive airway pressure [BiPAP and CPAP], respectively), while with the latter, negative pressure is applied externally to the abdomen and thorax to draw air into the lungs through the upper airway.

Supporting Evidence

This section lists and describes scientific evidence and jurisdictional guidance on the safety and procedures for transporting suspected or confirmed COVID-19 patients who require NIV support via standardly equipped EMS units. The Appendix provides detailed summaries of scientific evidence and Canadian/international guidance, respectively, on this topic. The majority of the information presented is taken directly from the identified sources.

  • Limited information was identified on land ambulances. Information on air ambulances was included, but it is unclear if these findings can be applied to land ambulances.
  • The majority of the information contains clinical guidance and/or recommendations; these recommendations are those of the authors of the original sources and the Research, Analysis, and Evaluation Branch does not have the expertise to evaluate such recommendations.
  • The methodological quality of most of the sources identified are unclear as they have not been assessed.

Scientific Evidence

Land Ambulance

  • Aerosol Shield: A Japanese study (Nov 19, 2020) described the design of a portable, reusable aerosol shield to cover the face of a patient during stretcher transport for ambulatory care (image). It is made of transparent vinyl chloride, and has four arm ports, one suction port to continuously maintain negative pressure inside the shield, six injection and oxygen ports, and the top of the shield is sloped ~20° to increase visibility. Intubation devices must be prepared inside the shield before the suction tube is placed through the side port.
    • Ten different emergency medical technicians tested the device during a routine training course on an adult-sized mannequin for tracheal intubation with video laryngoscopy, insertion of a laryngeal tube, and manual ventilation using a bag-valve mask. The intubation success rate was 100% for all trials. Data indicate that the shield may reduce the risk of viral contamination imparted by AGPs during emergency medical transport, although some aerosol leak may still occur.

Air Ambulance

  • Guidelines: Limited guidance is available, but NIV is generally permitted if appropriate precautions are undertaken (e.g., PPE, training). For example:
    • A Canadian study (June 24, 2020) highlighted Quebec Aeromedical Evacuation Services’ practical considerations for aeromedical transfers of confirmed or suspected COVID-19 patients: 1) pre-emptive endotracheal intubation is recommended for patients with the potential of respiratory decompensation during transport, regardless of COVID-19 status, to reduce NIV which is linked to increased transmission of infection; 2) prone position COVID-19 patients with acute respiratory distress syndrome; 3) transmit instructions before transports/transfers so local teams can adequately prepare the patient; 4) expect longer transfer times due to increased complexity of patient preparation, PPE, and decontamination processes; and 5) limit cross-contamination of the crew (e.g., masks, hot/cold zones).
    • The US Air Medical Physician Association’s position statement (Apr 3, 2020) supports the World Health Organization’s recommendation to employ standard, contact, and airborne precautions when caring for and transporting patients with suspected or confirmed COVID-19 infection who are undergoing AGPs, such as NIV. They recommend the use of a certified bacterial and viral filter in the ventilator circuit of NIV patients.
  • Airflow Characteristics: An Australian study (Nov 2, 2020) found that physical barriers between the cockpit and the cabin provide a degree of protection for non-clinical aircrew. Ventilation system settings can be used to generate airflow from the cockpit into the cabin to reduce cabin air entering the cockpit. Optimal positioning of the patient is on the aft or laterally orientated stretcher, depending on the type of aircraft. The disciplined use of PPE also enhances safety measures.
  • Patient Isolation Units (PIUs): Mixed findings were identified on the efficacy and safety of using PIUs to transport patients in air ambulances.
    • A review (May 14, 2020) described different methods used by several European organizations for transporting patients in open and closed PIU systems by helicopter and fixed-wing air ambulance during the COVID-19 pandemic. Small, closed PIUs may be especially beneficial for the air transport of intubated/non-intubated COVID-19 patients because: patients can be airlifted faster; additional decontamination between transports is not required; patients can be easily transferred from an airplane to a land ambulance or rescue helicopter, or vice versa; and all teams involved in transporting patients can be effectively protected.
      • For example, Swiss Air Rescue (Rega) developed and patented its own small PIU, which allows spontaneously breathing or mechanically ventilated patients to be transported (image). As of May 2020, the Rega fixed-wing air ambulance successfully transferred 13 confirmed COVID-19 patients, two of which were ventilated, in the PIU. All transports were well-tolerated, although in some cases mild sedation was necessary. Six ventilated COVID-19 patients were also transported without the PIU. As of May 2020, the Rega helicopter transported 83 seriously ill COVID-19 patients: 37 patients were spontaneously breathing, and 46 were intubated and ventilated predominantly in intermittent positive pressure ventilation mode.
    • A German study (Nov 24, 2020) found that the air ambulance transport of 13 patients with proven or suspected COVID-19 disease in a portable PIU, with the medical team on the outside delivering care through portholes, was a feasible option even over long distances (image). The main limitations of transports are limited access to the patient, reduced manual dexterity when delivering care through the porthole gloves, and disconnection of lines and tubes during loading/unloading procedures. An individualized risk-benefit analysis should be conducted for each patient prior to transport.
    • A research article (Jul 31, 2020) concluded that there was little advantage to be gained in moving patients with COVID-19 in isolation pods during aeromedical transfers. Patients are best managed in a sitting position, with supplementary oxygen if required, or on stretchers for those who can be best managed lying down. Ventilated patients should have a high-efficiency particulate air filter in the ventilation circuit and filtering face-piece 3 (FFP3) masks should be worn during AGPs (e.g., intubation, CPAP/BiPAP). In particular:
      • The Norwegian Air Ambulance Service reported mixed results from using PIUs. Some patients who may have been managed best in a sitting position were required to lay flat or semi-recumbent, and this had potentially compromised oxygen perfusion.
      • The United Kingdom Royal Air Force and Australian Defence Force experts emphasized the difficulty in managing ventilated patients in isolation pods and believed that the risks imposed outweighed any benefit
  • Helmet-Based NIV: A US study (Nov 23, 2020) reported that helmet-based NIV in air medical transport is a viable option for the safe transport of potential or unknown COVID-19 patients who present with hypoxemia and mild-to-moderate respiratory distress without any current or anticipated airway compromise or altered mental status. Patients who require supplemental oxygen at rates greater than six L/min, high flow nasal cannula, or CPAP/BiPAP are good candidates for this device (image).
    • The study reported on the experience of the first 10 uses of the device (nine times for an interfacility transport and once on a scene response): five patients were confirmed with COVID-19, three were suspected to have COVID-19, and two patients were considered low-risk. All patients were transported in the helmet without incident or complication, and none of the patients deteriorated during transport or required endotracheal intubation. In two instances, the neck seal was damaged during the initial application of the helmet and required a replacement. There were no cases of the neck seal failing during transport.

Land vs. Air Ambulance

  • A European study (Sept 22, 2020) found that the safe care and transport of 385 suspected or confirmed COVID-19 patients in PIUs, including 119 primary and 266 interfacility transport missions, was achievable across six different European ambulance services. Most patients transferred after on-scene calls were transported by ground ambulance, and these patients tended to be less sick than patients being transferred from one facility to another. Air transport (e.g., fixed-wing aircrafts) was the preferred method for patients who needed significantly more mission-related interventions and interfacility transport. NIV was used significantly more often in primary missions.

International Guidance

  • Guidance from the US (Centers for Disease Control and Prevention, Federal Healthcare Resilience Task Force, Arizona, California, Illinois, and New Hampshire), England, Luxembourg, and Australia suggest exercising caution if AGPs are absolutely necessary by using appropriate PPE (e.g., N95 masks, viral filters between masks and oxygen delivery ports to filter expired air) and infection prevention and control procedures (e.g., decontamination, opened rear doors of ambulance to promote air circulation) in land or air ambulances. For example:
    • Public Health England’s guidance (updated Jan 29, 2021) for ambulance services lists NIV as a medical procedure for COVID-19 that is aerosol-generating and associated with an increased risk of respiratory transmission. Respirators, disposable gloves, coveralls, and eye/face protection should be used. Patients should wear a surgical mask, providing it does not compromise their clinical care, such as when receiving oxygen therapy. Vehicles used for AGP procedures will require enhanced decontamination of all exposed surfaces, equipment, and contact areas with a chlorine-based product (or approved equivalent) before it is returned to normal operational duties.
  • California and Luxembourg adapted innovative approaches previously used to manage Ebola patients to transport suspected or confirmed COVID-19 patients:
    • Southern California designed six high-risk ambulances (HRAs) that were easy to decontaminate (e.g., HEPA filtration/UV light disinfection), had separate AC systems for the isolated driver and patient compartments, and achieved negative-pressure status for the treatment area (image). The HRAs have been used to transport passengers at high-risk of having COVID-19, and their use for confirmed COVID-19 patients is anticipated. While jurisdictions may choose not to build dedicated HRAs, the innovations implemented for this project should be considered when purchasing new ambulances for regular use.
    • In Luxembourg, European Air Ambulance uses an Infectious Disease Unit (IDU) or IsoPod (image). An IDU is a tent-like module originally designed for the safe transport of Ebola patients that has been adapted for COVID-19. It provides the patient space to move around, and allows for non-intensive treatment while still being completely isolated from the surroundings. An IsoPod is a smaller individual barrier-type unit, suited to patients not needing treatment, but which protects the medical team from infection. Due to restricted size inside, the IsoPod is not suitable for obese patients or patients who suffer from anxiety or claustrophobia.

Canadian Scan

  • The British Columbia Centre for Disease Control’s Interim Guidance (Mar 19, 2020) for the British Columbia Emergency Health Services (BCEHS) Critical Care Transport program, an air medical provider, suggests avoiding AGPs (e.g., CPAP), but airborne precautions should be initiated if it is required. If high concentration oxygen and/or positive pressure ventilation are required, the appropriate oxygen delivery system should be filtered with an antimicrobial, hydrophobic filter. As of May 2020, BCEHS is investigating the use of powered air-purifying respirators and PIUs.
  • Ambulance New Brunswick’s guidelines (Mar 27, 2020) for paramedics notes that an N95 respirator is required when performing AGPs on a person under investigation for COVID-19, including NIV.

Ontario Scan

  • Public Health Ontario’s evidence brief (Mar 29, 2020) on infection prevention and control for first-responders providing direct care for suspected or confirmed COVID-19 patients summarizes that droplet, contact, and airborne precautions (e.g., N95 respirators) should be used for AGPs, including NIV. This is consistent with guidance from the Public Health Agency of Canada and World Health Organization.
  • The Ministry of Health’s training bulletin (Oct 1, 2020) provides background information on COVID-19, current infection control guidelines, and links to resources. For oxygen administration for patients with symptoms of respiratory infection, the patient should wear: 1) a surgical mask, if tolerated, with a nasal cannula if low concentration oxygen is required; and 2) low flow/high concentration oxygen mask outfitted with a hydrophobic submicron filter if high concentration oxygen is required. Following every transport of a confirmed or probable case and/or the patient’s environment, paramedics must decontaminate the vehicle/aircraft, stretcher, and any reusable patient care equipment utilized during the call using a hospital-grade disinfectant in accordance with local Paramedic Service policies.
  • A study (May 13, 2020) discussed Ornge’s approach to preparing for the COVID-19 pandemic. As of April 30, 2020, Ornge organized transport for and/or transported 325 patients with either a confirmed case of or under investigation for COVID-19. A total of 52.3% of these were completed by critical care land ambulances, 28.9% were completed by fixed wing aircraft, and 16.6% were completed by rotary wing aircraft.
    • Ornge preferentially transports COVID patients using the critical care land ambulances, which are capable of 24 air changes per hour and the front driver’s compartment is separate from the patient compartment.
    • Ornge has temporarily halted the use of NIV. The study noted that there is emerging evidence to support the use of NIV to prevent mechanical ventilation in COVID-19 patients. However, there is substantial fear among health care workers about the increased risk of infection transmission from using these procedures. In cases where air transport is required because of geography, Ornge will require these patients to be mechanically ventilated. Ornge will be participating in engineering research trials looking at the risk of droplet and aerosol dispersion using NIV in airframes based on their airflow dynamics.
    • See the study for further details about Ornge’s screening, PPE, decontamination, and surge capacity approaches.


The COVID-19 Evidence Synthesis Network is comprised of groups specializing in evidence synthesis and knowledge translation. The group has committed to provide their expertise to provide high-quality, relevant, and timely synthesized research evidence about COVID-19 to inform decision makers as the pandemic continues. The following member of the Network provided evidence synthesis products that were used to develop this Evidence Synthesis Briefing Note:

  • Ontario Health (Cancer Care Ontario). (February 22, 2021). Safety of transporting COVID-19+ or Suspected positive patients by air (for HCPs).
  • Ontario Health (Cancer Care Ontario). (February 23, 2021). Safety of transporting COVID-19+ or Suspected positive patients by ambulance (land and air) (for HCPs).