By Jess Hegedus
We had a fantastic, mixed-bag education day for March at Sydney HEMS. Our presenters covered logistical issues in retrieval (ranging from canals, tasking and weather), confronting change in our clinical practice and trauma hypothermia. We also worked on some new skills, including serratus plane blocks for rib fractures and insertion of our new large bore trauma line and ultrasound guided subclavian vein cannulation.
Pre-hospital care in Venice
Source: Wiki Commons
At Sydney HEMS, we love discussing logistical challenges in pre-hospital and retrieval medicine (PHEM), and learning from other services. Dr Giacomo Magagnotti, a PHEM physician in Venice, Italy, provided a fascinating presentation on how this service is provided in the City of Canals.
Venice is a series of 118 small islands which form a single city, connected by (often crowded) canals and bridges and a single road bridge that connects the city to the Italian mainland. The city has approximately 82 000 permanent residents, but amazingly receives around 52 000 tourists per day. Other particularities in Venice include narrow walkways, limited access to online maps and an absence of sequential street numbers and names, with buildings numbered according to age, requiring extensive questioning and local knowledge to locate patients. This is clearly a unique and challenging environment in which to provide pre-hospital care, and at several points Giacomo highlighted the importance of early consideration of patient extrication and transport logistics.
In this setting, a well organised emergency medical service is provided that utilises paramedics, nurses and doctors, depending on the clinical priority assigned to a case. Unsurprisingly, the vast majority of responses are by boat, which again carry unique considerations. Boats require careful weight distribution for safety and the low roofs make management of patients very difficult in transit, again requiring careful planning and anticipation of possible issues. Patients commonly require transport to the mainland due to the limited services available at the local hospital, and this requires a combination of boat and road transport, or occasionally the use of a helicopter which is shared between multiple emergency services. Significant planning is required prior to public events, due to a highly dense environment during peak tourist periods and the logistical issues described above. The service considers where boats can dock, where the helicopter can land, where a field hospital is best located, the best route to the road bridge to the mainland and what city resources will be available. On top of thorough planning, Giacomo reported that their service operates well due to a strong sense of community within Venice.
Clinical prioritisation in the aeromedical control centre (ACC)
Dr Neil Ballard is a Sydney HEMS retrieval consultant, and state retrieval consultant in the ACC, who outlined for us the workings of the ACC in terms of history, triage and tasking. The ACC was developed in 1997 to provide central control of NSW aeromedical operations and now oversees more than 15 000 missions per year. The centre operates with a team including paramedics, nurses and a physician and responds to requests for inter-hospital retrievals between facilities and identifies patients in the pre-hospital setting that would possibly benefit from the involvement of an aeromedical team.
Broadly, jobs being reviewed by the ACC are considered and prioritised according to the clinical condition of the patient, the reason that they require transfer (e.g. for an urgent procedure) and the capabilities of the referring facility. Based on this assessment, the job is assigned a numerical clinical priority, which dictates our response time. For helicopter retrievals, this clinical priority is considered alongside an estimation of aviation risk, provided by the pilot. At times when these priorities clash, this requires a pause point and discussion amongst the team and ACC to consider how the patient can most safely be attended to within the required timeframe. Neil concluded his presentation with some case discussions, highlighting the challenges in remote assessment and prioritisation often presented to the team at the ACC.
The weather and HEMS operations
As mentioned above, one of the essential components of helicopter mission planning and feasibility is an assessment of aviation risk, made by the pilot in charge of the aircraft. This is heavily influenced by weather and it was fantastic to have Toll pilot Tim Frankel provide a presentation on the effect of weather on helicopter operations to help demystify some elements of this assessment for our medical teams.
During Summertime, our operations might be affected by:
- High temperatures which increase the density of air, reducing aircraft performance. This effects fuel requirements, load/weight capacity and makes hovering more difficult (which may affect winching operations).
- Storms are more frequent and may cause turbulence, icing on the aircraft, environmental interference and damage from heavy rain, hail and lightning.
- “Southerly busters” are an abrupt cool change occurring after hot conditions, common in NSW. The sudden temperature change can be intense, potentially affecting operational planning and may be associated with intense turbulence and thunderstorms.
- “East Coast Lows” are a weather phenomenon occurring off the East Coast of Australia. They are intense low-pressure systems that bring heavy rain and wind, rough seas and low cloud, affecting visibility and safety of aircraft and water operations.
- The Sydney basin and other low-lying areas are susceptible to fogging in Winter, usually lasting until mid-morning.
- Westerly winds develop from intense low-pressure systems that form in the Southern Ocean, resulting in tight pressure gradients around the East Coast. These occur mostly in late Winter/early Spring and can result in severe turbulence, that may last several days.
One of our critical care paramedics, Sam Immens, gave us a sneak preview of his upcoming SMACC talk in which he explores change. Whilst I won’t give away the details here, Sam provides a thoughtful consideration of why thinking about our response to change matters, and how we can respond well to change in critical care practice as both individuals and organisations. If you’re going to SMACC I highly recommend checking this out.
Next up we heard from Sydney HEMS registrar, Dr Antti Kamarainen. Antti has come to us from Finland, where the temperature was -15 degrees Celsius on the day of this talk, therefore hypothermia prevention is an essential consideration in his practice back home. Antti provided a run-down of the pre-hospital prevention and management of trauma-induced hypothermia, using an article by Bennett & Holcomb (2017) (reference below).
The hypothermia that we might encounter in the pre-hospital setting may be primary, due to cold environmental conditions in otherwise healthy patients (defined as less than 35 degrees Celsius) or trauma-induced. Trauma-induced hypothermia (TIH) is a result of altered heat generation and possibly altered thermoregulation following a traumatic injury, and in this setting, problems will begin to arise at temperatures less than 36 degrees C. The postulated mechanisms of TIH include an increased reliance on anaerobic metabolism, resulting in less ATP (and subsequently, heat) generation and possibly damage to thermoregulatory centres following traumatic brain injury. This is a pathological response, and may occur even in trauma patients even in normothermic conditions and is associated with acute traumatic coagulopathy and worsened outcomes in trauma patients.
In the pre-hospital setting, our patients may lose heat via all mechanisms (conduction, convection, radiation and evaporation) – they are often exposed, may be in cold and/or wet environments and in contact with cold surfaces. This may be exacerbated by our assessment and management, e.g. cold blood products. Unsurprisingly, risk factors for TIH are entrapped patients, wet patients, extended exposure or time on the ground and cold ambient temperatures.
Management of TIH should be geared towards prevention, and the article suggests several possible measures:
- Limit additional loss by removing patient from the ground, protecting from weather and removing wet clothing
- When examining patients, expose only the area of interest, then re-cover
- For entrapped patients keep them warm and protected during extrication. For example, Antti described that in Finland they use hot air blowers and beanies for patients entrapped in vehicles.
- Use of pre-prepared ‘hypothermia prevention management kits’ in high-risk patients (e.g. polytrauma, massive haemorrhage, water exposure or cold ambient temperatures, entrapped or head injured patients)
Our options at Sydney HEMS for the prevention and management of hypothermia include use of space blankets and/or heating blankets (which can be pre-prepared on the stretcher), controlling the temperature in the aircraft or vehicle, and use of a sleeping bag during stretcher winches.
Serratus anterior plane (SAP) block
Sydney HEMS consultant and specialist anaesthetist Dr Rob Scott delivered a skills station on the (SAP) block, a simple and low risk regional anaesthesia technique for anterior and lateral rib fractures. This block provides somatic analgesia to this region by blocking the lateral cutaneous branches of the T2-T9 intercostal nerves and the long thoracic nerve. The SAP block has previously been well described on this blog – see here for more information:
Image: Ultrasound view for SAP block
Large bore trauma line insertion
In our second skills station, Sydney HEMS consultant and emergency medicine specialist Dr Alex Tzannes provided a hands-on skills station covering the insertion of a 7Fr trauma line, which is a recent addition to our packs.
For a great run down, please check out this video made by Alex and Dr Vekram Sambasivam: https://www.youtube.com/watch?v=m1_oO5GdUHU
As a bonus, Alex also demonstrated a technique for getting around the T-pod pelvic binder to insert a femoral venous line and using ultrasound for a supraclavicular approach to subclavian venous access.
Please see here Alex and Vekram’s video on femoral line insertion with the T-pod in situ: https://www.youtube.com/watch?v=H_ZDQ_3rLtk
Bennett, B & Holcomb, C (2017), ‘Battlefield Trauma-Induced Hypothermia: Transitioning the Preferred Method of Casualty Rewarming’, Wilderness and Environmental Medicine, 28, S82-89