Report: Lt Col N T Tarmey RAMC, Maj C L Park RAMC, Lt Col M Fox RAMC, Lt Col T Lowes RAMC, Surg Cdr A Mellor Royal Navy, Col P F Mahoney L/RAMC
Anaesthesia for Overseas Operations: UK Military Guidelines
The aim of this article is to share our recent experience of deployed military anaesthesia with the international community. In the United Kingdom Defence Medical Services (UK-DMS) we have recently completed a major revision of our Clinical Guidelines for Operations (CGOs). These guidelines aim to provide practical, concise guidance for deployed clinicians. We suggest these may also prove useful for other international military and civilian anaesthetists managing severely injured casualties in challenging environments. Here we present three of our core guidelines: Trauma Anaesthesia in the Established Role 3 Field Hospital; Rapid Sequence Induction in the Emergency Department; and Anaesthesia for Thoracotomy.
Combat casualty care has changed enormously over the last ten years, not least because of the number and severity of casualties treated by military teams in Iraq and Afghanistan. We aimed to capture this clinical experience, along with recent research, in a set of concise flowcharts to guide clinicians for future conflicts. These guidelines presume a degree of pre-existing knowledge and experience, and are designed for use by a practicing consultant-level anaesthetist. They do not aim to teach an experienced anaesthetist how to give an anaesthetic; instead they focus on the special considerations of managing a severely injured casualty in a challenging environment.
Our guideline development process began with a working group of subject-matter experts, who convened at a dedicated “controversies” meeting to discuss the key questions arising from recent research and overseas operations. Each topic was then delegated to teams of 2-3 experts, who produced draft guidelines for consensus-based approval by the larger group. The final guidelines have been incorporated into team-based pre-deployment training and are subject to a process of continuous review.
The trauma anaesthetist’s role in the field hospital begins with Damage Control Resuscitation (DCR) from the time of arrival in the Emergency Department (ED). Anaesthesia is just one part of the DCR process, which also includes permissive hypotension, haemostatic resuscitation, and damage control surgery. Anaesthesia must be induced at the most appropriate stage in this process, and the trauma anaesthetist needs a full understanding of the casualty’s cardiovascular status as well as identified and potential injuries.
An early priority in DCR is to identify the main source(s) of bleeding. General anaesthesia may be required to comfortably, safely and rapidly perform the imaging required to achieve this. Source control of haemorrhage should not be delayed to pursue resuscitation, however bolus administration of blood products at the time of anaesthetic induction may help to prevent catastrophic cardiovascular collapse. In the bleeding patient this bolus therapy should be carefully monitored and balanced against the administration of anaesthetic drugs to maintain a state of temporary, controlled hypotension. In a few circumstances it may be more appropriate to anaesthetise a bleeding patient on the operating table rather than in the ED. Hypotension in a bleeding casualty should be treated by infusion of further blood products rather than the use of vasopressors as these may increase mortality in such patients.
The flowcharts in figures 1-3 cover key anaesthetic considerations during resuscitation and surgery in trauma casualties. Anaesthesia for thoracotomy is specifically discussed in figure 3 as guidance for anaesthetists who do not normally practice cardiothoracic anaesthesia. Emergency thoracotomy may be required for a number of reasons in trauma casualties including: release of pericardial tamponade; proximal haemorrhage control; internal cardiac compressions; and surgical treatment of penetrating thoracic injuries.
Effective communication and other non-technical skills are essential for trauma teams to function at the highest level. The ED Team Leader will remain in the Team Leader role until after the casualty is transferred and stabilised on the operating room table. This allows the anaesthetic team to focus on establishing anaesthesia before the lead anaesthetist takes over this leadership role. At this point an abbreviated World Health Organisation surgical checklist is performed to confirm the casualty’s identity, injuries found, initial surgical plan and physiological stability including blood products transfused.
At regular intervals throughout surgery, the deployed anaesthetist will update the surgeon in a two-way communication process aimed at keeping the whole team informed of key issues. This helps prevent surgeons and anaesthetists from becoming overly “task focused” and ensures passage of key information. This includes blood loss, blood product transfusion, physiological stability, and any identified coagulopathy. For rapid assessment of coagulopathy, the UK-DMS now uses point-of care RoTEM thromboelastometry.
Effective communication also requires timely discussions of limitation of surgical intervention in unstable patients and futility discussions in those that are unsalvageable. Our deployed field hospital team now includes a Deployed Medical Director (DMD), a senior military consultant who takes an active leadership role in these complex and difficult clinical decisions.
Combat casualty care has advanced greatly over the last ten years. During this time the role of the deployed anaesthetist has expanded and developed to provide high quality damage control resuscitation and anaesthesia. These guidelines provide practical and concise guidance to military and civilian trauma anaesthetists working in high-pressured, austere environments.
Source: Medical Corps International Forum (3/2013)