Photo courtesy of Dr Nicholas Chrimes
Prehospital Airway management
Training and competency
There exists no uniform international standard as to what constitutes the minimum level of training and competency deemed necessary to provide safe and effective prehospital airway management. The differences between various countries as to what is considered standard training and which professional background should provide prehospital airway management is telling. When such significant differences exist between multiple providers across different countries, the only logical conclusion must be that there exists no best practice standard.
Predominantly European nations espouse the belief that the dedicated medical specialist doctor with anaesthetic and specific prehospital training is the preferred provider of advanced airway management or as the Scandinavian Society for Anaesthesia and Intensive 2008 published guidelines on Prehospital Airway management cite “Anaesthetic training and routine in anaesthesia and neuromuscular blockade is necessary for most of the techniques in the treatment of patients with airway reflexes” Provocatively they state “Other physicians, as well as paramedics and other EMS personnel, are recommended the lateral trauma recovery position as a basic intervention combined with assisted mask-ventilation in trauma patients. When performing advanced cardiopulmonary resuscitation, we recommend that non-anaesthesiologists primarily use a supraglottic airway device” .
French, German and British prehospital and retrieval services have taken a very similar stance on this issue of the standard training of the prehospital provider of advanced airway management. The reader should note however, the difference in approach to this in North America where flight nurses and paramedics are routinely training and credentialed to provide the full range of prehospital airway interventions including use of neuromuscular blocking agents to facilitate securing of the airway. The level of training is variable with no national standard for advanced airway management. One aeromedical service mandates flight paramedics must maintain a log book demonstrating at least one prehospital tracheal intubation per month over a year and failure to do so dictates a mandatory upskilling session in the operating room under anaesthetic specialist supervision of a minimum number of intubations.
In Australia, most prehospital advanced airway management is conducted using a prehospital doctor from a background in anaesthesia, emergency medicine or critical care. In general the widely held belief in prehospital and retrieval services in Australasia , is that a minimum experience in hospital based anaesthesia training is required in order to provide safe prehospital advanced airway management. There is once again no agreed standard nationally but one retrieval credentialing standard used in Queensland mandates at least a 6 month anaesthetic experience for retrieval doctors in that state. However in the state of Victoria, the intensive care paramedic system, does train and credential paramedics with the capacity to provider prehospital advanced airway management.
One question the reader should always bear in mind when considering the training and competency standards for a prehospital airway provider is where and what should such training consist of. Is a purely hospital based initial and subsequent refresher program sufficient for the needs of the prehospital and retrieval practitioner? If as the Europeans suggest, anaesthetic training is fundamental then does this adequately address the competencies for a surgical airway in the prehospital setting when a hospital anaesthetist is predicted to encounter one surgical airway scenario in a whole career? Hospital anaesthesia has become a routinely safe process, mainly through the strategy of risk mitigation and the elective application of increasingly sophisticated techniques. To transpose such a hospital based elective strategy into the arena of prehospital and retrieval medicine can not only be challenging but inappropriate at times. Prehospital airway training should emphasise the safe and skilled use of a limited range of simple but effective techniques using a small set of equipment. One small study in North America found that the the Commission on Accreditation of Medical Transport Systems (CAMTS) initial and maintenance intubation training standards on 12 flight nurse novice intubators over a 1-year period did maintain simulated difficult airway intubation success rates. These require a minimum of one successful intubation per 3 months on a live, cadaveric or mannequin based patient.
Competency in this area should be demonstrable by the successful application of such skills in varying conditions common to the prehospital setting , in either simulation based assessment format or directly supervised real world cases. What is clear when examining the prehospital airway research is that lecture and mannikin based training alone is insufficient for not only initial airway training but ongoing maintenance of skills. One suggested training strategy by Dr Levitan, a prominent emergency airway researcher, is to begin with the least risky training using internet based and video anatomy teaching, then progress to mannikin training to allow repeated safe practice. The next stage involves attending ear, nose and throat outpatient clinics to review and examine live anatomy and pathology. Following on from this is experience in an elective ENT surgical list as an observer and/or assistant, allowing review of surgical airway techniques and anatomy to occur as well as laryngeal inspection. Supervised supraglottic airway techniques and orotracheal intubation in elective anaesthetic attachment is the next step in the training. After this, the level of risk in the training is increased into supervised airway management in the ED or ICU, where the likely patients encountered in the prehospital setting will be seen. Finally the ultimate level of airway training is in supervised real world airway interventions and decision making in the prehospital and retrieval settings. This method of training is very structured and goal oriented unlike the traditional view of a minimum time spent in anaesthetic training, where goals are often not predetermined nor specific to the needs of the prehospital provider. Ongoing research and clinical audit of prehospital airway management will help us decide eventually what is the best practice approach to training and competency.
Any emergency service that aims to field providers competent in prehospital airway management should have a system of credentialing, regular clinical audit and quality review of airway skills.
Credentialling is the process whereby an individual’s past experience and training are formally verified and considered against a range of criteria that the organisation deems essential to adequately perform a given task or set of tasks. For example in Queensland, retrieval medicine credentialing requires that full scope of unsupervised practice, at least 6 months of anaesthetic training as proof of adequate airway skills attainment. Clinical audit is the process whereby regular reviews of airway procedures on given cases, usually chosen at random or fitting set criteria for audit ( all tracheal intubation cases for example), occurs in a systematic manner. Audit aims to set a minimum standard of care in airway management in the prehospital setting by judging the performance of a given airway intervention against set agreed criteria, usually in a retrospective fashion. For example, if tracheal intubation was performed, was end tidal capnography used to confirm correct placement? Systems that use mandatory procedural checklists for airway interventions are able to effectively perform clinical audit as the checklists can be used to determine if a standardised approach was conducted. Quality review and assurance is the process whereby a given performance of an intervention is judged to meet minimum standards of safety and peer review. It is a global assessment of not only the outcomes of the procedure but the decision making process and contingency planning for common complications. For example the emergency airway literature has cited factors such as number of intubation attempts and overall success of intubation as some criteria to judge overall quality of prehospital airway care. These are by no means the only significant factors to consider in quality review. The San Diego RSI trial of paramedic provided intubation demonstrated high rates of significant hypoxia and hyperventilation during the airway interventions with an overall worse outcome in the treatment group. The Melbourne MICA RSI trial for head injured patients showed a significant increase in cardiac arrest in the prehospital RSI treatment group ,possibly due to the use of RSI drugs in hypotensive patients. Therefore it is important in quality review of prehospital airway management to look at a global assessment of the airway intervention from decision making and preparation right through to post intubation care and monitoring.
Evidence base for prehospital airway management
Whilst this may seem a surprising area to be considered controversial, the reader should try to answer a simple question first before proceeding.
“What are the sentinel studies demonstrating a clear benefit in prehospital intubation and/or rapid sequence induction of anaesthesia for the trauma patient or the critically ill patient?”
Unfortunately this question cannot be simply answered as such studies do not exist. Some readers may argue that there is no point in trying to answer this question as tracheal intubation and rapid sequence induction are considered standard of care in hospital settings for critically ill and injured patients. Therefore the logic demands that if its good enough in hospital, so be it for prehospital settings. Many attempts to prove this in research have failed to demonstrate a clear benefit for trauma patients. In the traumatic head injury group, some studies demonstrate an advantage to prehospital intubation but many studies do not as well. The Paramedic MICA RSI trial in Victoria, Australia was one randomised controlled trial examining the benefit of rapid sequence induction and intubation for head injured patients. At 6 month outcome, there was a small significant advantage in neurologic condition in the prehospital RSI group. Unfortunately there was a significant increase in cardiac arrests in the prehospital RSI group, albeit no overall increase in mortality between control and treatment groups. The other RCT trial was in a paediatric population, and tracheal intubation without use of drugs was performed by paramedics who had limited training(5). This failed to demonstrate any benefit to prehospital intubation compared to bag/valve face mask ventilation.
Along the way in this debate has been the line of arguement that only doctors should be performing prehospital RSI as allegedly paramedics do not have enough experience to do this safely. Certainly published research out of Europe and UK have demonstrated a much higher claimed success rate for prehospital RSI with little complications when performed by senior prehospital doctors compared with paramedics. The San Diego RSI trial added more cold water into the arguement in favour of prehospital RSI by demonstrating a clear survival disadvantage for head injured patients undergoing paramedic led prehospital RSI. Careflight NSW Head Injury Retrieval Trial has been collecting randomised data examining this issue of the benefit of prehospital RSI by a helicopter borne critical care physician in the head injured patient compared to paramedic led road ambulance care. The HIRT trial was the largest RCT trial of its type in the world and failed to show a significant difference in mortality outcome benefit between the two groups. It was plagued with methodologic issues such as treatment crossover.
So where does the truth lie for prehospital airway management? The evidence suggests that the experience and training of the prehospital provider performing RSI and intubation does make a difference in minimising complications. Therefore regardless of the background of the retrieval provider, it seems common sense looking at the evidence to ensure they have adequate initial training and ongoing maintenance of their airway and anaesthetic skills. What this means in real terms is difficult to say as once again the evidence base into this area of “sufficient airway training and ongoing skills maintenance” is scant. One study out of the London HEMS retrieval service indicates that at least 6 months of formal hospital anaesthetics training is required to achieve a sufficiently high intubation success rate. Other published articles stipulate a minimum of at least one retrieval intubation per month to maintain skills or an initial successful completion of 57 intubations to achieve a intubation success rate of greater than 90%.It is the author’s opinion that prehospital RSI should be beneficial in most critically ill and injured patients when performed by providers who are experienced and maintain high level of skills maintenance and case volume. To become good at prehospital RSI you probably need to be doing it at least several times a week, with a well rehearsed prehospital team/assistant , working from a well trained standard operating procedure with a standard setup of drugs , monitoring and airway equipment. If you work in a retrieval service that does not provide sufficient volume of prehospital RSI cases, then unless you are maintaining your airway skills elsewhere such as hospital work, you are likely to suffer significant airway deskilling to the point of becoming substandard competency within a short period of time. Whilst your emergency airway skills will never reduce to the level of a novice, it seems fool hardy thinking to assume you will be as competent as a provider who is performing prehospital RSI 3-4 times more often than you are! Sports and human factors research clearly demonstrates this.
The obvious alternative question to consider in this topic is whether tracheal intubation is absolutely necessary for all critically ill and injured patients? Certainly the cardiac arrest research in the last 10 years has demonstrated consistently worse outcomes in arrested patients who were intubated compared with controls. The latest international resuscitation guidelines stipulate that a laryngeal mask airway is considered an advanced airway equal to a cuffed tracheal tube for the purposes of advanced life support. This issue has received virtually no attention in the anaesthetic or critical care research field apart from some case reports in the use of laryngeal mask airway for transport ventilation of neonates and in the failed intubation scenario for a trauma patient on retrieval. The author has published a prehospital intubation audit in which 3 cases of failed intubation were all successfully managed and transported using a laryngeal mask airway. Uncuffed paediatric tracheal tubes are in many services still considered standard of care for emergency intubation but what they offer for airway protection compared to the laryngeal mask airway, in particular the older Proseals or newer paediatric LMA Supremes, both with gastric drainage ports, is difficult to say and indeed prove. May there come a day in retrieval medicine whereby the paradigm in airway management has shifted to a focus on oxygenation instead of intubation, using RSI to insert primarily a supraglottic airway device such as a LMA and if oxygenation and ventilation are adequate then transporting with said device in situ? In 2014 the UK Faculty of Prehospital Care issued a consensus statement on the technique of PALM, pharmacologic assisted laryngeal mask, advising that this was a reasonable approach for providers who were not credentialled for RSI. It seems unlikely that this will replace endotracheal intubation as the gold standard prehospital airway but it certainly opens up the discussion as to what constitutes prehospital airway management and how what is best , will depend on the situation, provider and the patient.
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