Case-type: Personal protective equipment / clinical logistics
Author: Stian Mohrsen, HEMS Paramedic (University Hospital Southampton / Hampshire and Isle of Wight Air Ambulance)
Public Health England has established the COVID19-pandemic as so wide-spread, that any patient in the pre hospital environment is considered a significant transmission risk.
UK charity air ambulances are in varying degrees affected by challenges to airframe decontamination, staff redeployment and acquisition of personal protective equipment (PPE).
This has led the services to change their mode of operation, and contribute to other areas of health care that have sprung out in response to the pandemic.
Implementing adapted processes, and assuming a clear clinical approach can help prevent transmission and uphold service integrity.
UK Helimed 56 (HM56) was called to a motorway single-vehicle road traffic collision. The aircrew consisted of a doctor and two paramedics. On approach to land, the aircrew could see that the ambulance service and the hazardous area response team were in attendance.
HM56 was forced to land in an adjacent field, as traffic was still moving on the opposite carriageway. After negating a tall motorway fence to gain access to the scene, the HEMS doctor donned a surgical face mask, gloves and an apron and approached the crashed vehicle to liaise with the ambulance crew.
The patient was medically trapped with a head injury, combative and agitated. With this knowledge and a decision to provide pre hospital emergency anaesthesia (PHEA), one paramedic prepared a syringe of Ketamine while the other laid out FFP3 face masks, surgical head caps, full face visors, gauntlet gloves and Tyvek suits.
One of the paramedics and the doctor donned the personal protective equipment before returning to the patient side to aid extrication.
The third crew-member established a cordon on the left hand side of the ambulance where no patient-facing personnel would be allowed, and designated the rear of the ambulance for the anticipated aerosol generating procedure.
Equipment and drugs for PHEA and maintenance sedation was prepared in the clean zone and deposited into the ambulance from the side door, allowing contaminated crew members to retrieve it via the back of the ambulance.
The patient was successfully intubated and connected to a closed circuit, and brought to the major trauma centre 15 minutes away by road.
The ‘clean’ crew member travelled in the front of the ambulance; and provided a hospital pre alert and dispensed drugs and equipment to the crew members travelling in the patient compartment, through the bulkhead hatch.
COVID19 is a virus causing severe acute respiratory syndrome (SARS), and is abbreviated from «coronavirus disease 2019». The viral pandemic originated in China’s Wuhan region at the end of 2019 (Sohrabi et al, 2020) and was declared a global health emergency by the World Health Organisation (WHO) (2020a) a month later.
It took another three weeks before Public Health England (PHE) (2020a) released its first novel coronavirus-specific guidance for ambulance services, which has since been adapted numerous times, with increasing knowledge and emerging evidence.
The outbreak has been established as having such a sustained spread in the UK that any patient encounter (within 2 metres) requires a degree of personal protective equipment.
High demand and low supply, along with helicopter emergency medical services (HEMS) staff redeployment to frontline ambulance service has left some air ambulance services in a deficit of protective equipment, and some having to ground assets (Wales Air Ambulance, 2020; Yorkshire Air Ambulance, 2020).
Hampshire and Isle of Wight Air Ambulance (HIOWAA) holds central professional cooperatives with Babcock and University Hospital Southampton (UHS). The former supplies aviation services, while UHS employs and governs the HEMS paramedics.
The HEMS doctors are consultants which hold substantive posts at various hospitals in the county of Hampshire.
HIOWAA has been able to continue operations throughout the pandemic, and expand its efforts into other areas in anticipation of a regional or national caseload surge.
Paramedics are redeployed to the UHS emergency department to work alongside nursing and medical staff, and HIOWAA is also one of few charity air ambulances supporting a Royal Air Force COVID19 task group in long distance national aeromedical retrieval (Bullock, 2020).
These changes have been facilitated by reducing assets from two double-staffed vehicles per day (helicopter and response car), to a single helicopter response with three medical crew members.
This ensures that the service maintains HEMS operations, and provides a ‘clean’ crew member to manage logistics and communications.
Transmission, AGPs & PPE
Symptoms of COVID19 are described as flu-like with a persistent cough and shortness of breath as leading features (Centers for Disease Control, 2020; Public Health England, 2020b).
Gastrointestinal symptoms and faecal transmission have been thought significant (Wong, Lui & Sung, 2020), and Public Health England (PHE) (2020c) advises that any patient-generated liquid with the exception of sweat should be treated as potentially infectious.
World Health Organisation (WHO) and United Nations Children’s Fund (2020) dismiss the risk of transmission through excretions as low and unsubstantiated, however Zheng et al (2020) established high viral loads in stool only two days prior to the WHO and UNICEF guidance.
It is therefore reasonable to maintain caution around any bodily secretion and excretion.
Regardless, droplets from the respiratory tract remain as the main concern for transmission, and will also be of most relevance to pre hospital teams.
Droplets can infect through primary exposure and secondarily via contact surfaces (PHE, 2020c). As the lower airways have shown to hold a significant viral load through the course of the disease as well as after the end of symptoms, there is a risk of producing airborne particles when performing aerosol generating procedures (AGP) (Wölfel et al, 2020).
The AGPs are defined by the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG), which informs the guidance produced by Public Health England.
Currently, the list of aerosol generating procedures include:
- intubation, extubation and related procedures, for example, manual ventilation and open suctioning of the respiratory tract (including the upper respiratory tract)
- tracheotomy or tracheostomy procedures (insertion or open suctioning or removal)
- bronchoscopy and upper ENT airway procedures that involve suctioning
- upper gastro-intestinal endoscopy where there is open suctioning of the upper respiratory tract
- surgery and post mortem procedures involving high-speed devices
- some dental procedures (for example, high-speed drilling)
- non-invasive ventilation (NIV); Bi-level Positive Airway Pressure Ventilation (BiPAP) and Continuous Positive Airway Pressure Ventilation (CPAP)
- High Frequency Oscillatory Ventilation (HFOV)
- induction of sputum
- high flow nasal oxygen (HFNO)
(Public Health England, 2020d, par. 8.1)
Interactions with any patient (within 2 metres) requires the use of level 2 PPE as a minimum, and any aerosol generating procedure must only be undertaken while wearing level 3 (Table 1).
CPR – a contested topic
On this note, cardiopulmonary resuscitation (CPR) has become a contested topic. Guidance from the UK Resuscitation Council (UKRC) has treated chest compressions as an AGP since the beginning of April (2020).
This position was asserted in a statement published 20th April, which challenged Public Health England’s choice to not identify chest compressions as aerosol generating (UKRC, 2020b).
Presumably in response to this, PHE updated its guidance four days later, reaffirming chest compressions as a non-AGP (PHE, 2020d).
HIOWAA had adopted the AGP-guidance from both Public Health England and the UKRC, and extended it to include chest decompression by both needle and scalpel technique, as well as procedural sedation.
There is no published evidence to support these as aerosol generating, but they have been included by rationale. Chest decompression is performed to release pressure, which can be caused by a pathologic conduit between the lung and chest cavity as in a closed pneumothorax.
The procedure itself can also cause an iatrogenic passageway through either technique. Procedural sedation itself is not aerosolising, but adverse effects of over-sedation, or ketamine-induced laryngospasm would trigger airway instrumentation (Royal College of Emergency Medicine, 2019).
Providing care and avoiding transmission
Many of the skills added by HEMS teams are defined as aerosol generating, requiring level 3 PPE.
HIOWAA uses a setup of FFP3 face masks, surgical caps, full face visor, Tyvek suits and double gloves with one pair being high-hilted. As an added measure, a paramedic crew member will avoid getting within two metres of the patient and remain with the equipment, preparing whatever drugs or technical equipment required.
Most materiel used by HIOWAA is similar to that used by the local ambulance service, which makes it easier for the HEMS team to limit exposure of its own equipment; while still adding advanced drugs, video laryngoscopy and surgical airway equipment, surgical skills and pre hospital blood transfusion.
The revised HIOWAA standard operating procedure for pre hospital emergency anaesthesia (PHEA) has been altered to fit with new guidance.
Airway management is designated exclusively to the most experienced airway interventionist in the team, which should be done using video laryngoscopy (Cook et al, 2020).
To limit the spread of aerosols, ventilations are withheld until the circuit is closed by cuff inflation, the use of a micro-particle filter and a closed in-line suction circuit.
No patient by air unless confirmed negative
At the moment no patients are transported by air unless they are confirmed negative for COVID19, due to challenges in aviation-instrument decontamination.
Babcock (2020) has recently taken steps to mitigate this by the installation of a separation curtain, but this has yet to affect HIOWAA’s decision to non-convey.
Most of Helimed 56’ primary response area has excellent road infrastructure, and the critical care team’s modus operandi would be to ‘deploy by air, deliver by road’ in the majority of cases even before the pandemic.
It seems appropriate to limit the risk of aircraft contamination, factoring in that HIOWAA only has a single aircraft at disposition.
When Helimed 56 attends an incident, the lead clinician and the most suitable other crew member will don appropriate PPE. The third crew member will designate a clean area where they can work, and if possible an area where AGPs are performed unless this must happen where the patient is found situated.
This role yields a high task-load, and can be helped if there are other uncontaminated health care professionals to employ in the clean area. In any case, clear communication and logistics must be fluent at all times to ensure the integrity of equipment and crew.
The clean area should be upwind of any AGP, and it can be beneficial to use the ambulance as an intermediary space between a clean and a contaminated site when circumstance and vehicle design allows (Illustration 1).
The inside of the ambulance is treated as contaminated, and kit can be delivered in from the side where it becomes accessible to contaminated personnel from the rear of the vehicle.
It is already typical for Helimed 56 to perform PHEA and surgical procedures on the ambulance stretcher at the back of the attending ambulance.
This allows 360 degrees access to the patient, short distance to retrieve spares in case of equipment failure (other than that accounted for in preparation) and quick access to the inside of the ambulance to keep momentum towards definitive care.
An added benefit is that the AGP is performed in a well ventilated area, adhering to recommendations set by WHO (2020b); and it reduces contamination to contact surfaces once inside the ambulance, as long as the circuit remains closed throughout.
The front compartment of the ambulance remains clean throughout. In an effort to maintain this, the clean HEMS crew member will assist the driver in a safe doffing procedure developed by the HIOWAA clinical management team.
The clean crew member can then keep equipment clean in the front cab, and prepare and pass any required equipment through to the clinical team.
At the end-point, the safe doffing procedure is again applied to the clinical team after hospital handover. As a rule, minimal amount of non-consumable equipment requires decontamination, and can be decontaminated with disposable viricidal wipes, making the HEMS team ready within minutes.
COVID19 is now assumed in the populace and poses a real risk to healthcare personnel, particularly through transmission by droplets and subsequent contact with affected surfaces.
The novel coronavirus infests the respiratory tract throughout the course of illness, causing procedures and instrumentation that convert droplets to aerosols to be of particular high risk. In turn, these require sharpened mindfulness around safe distancing and use of personal protective equipment.
Constantly changing environments are a hallmark of pre hospital practice, and critical care teams operating in these conditions must remain adaptive and resilient.
Readily available processes are necessary to keep healthcare providers and patients safe, and clear communication and understanding of roles can enforce this at the roadside.
Bearing in mind that the particular case example given in this article is not readily generalisable, many of the underpinning principles are.
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