Abstract
Pre-hospital airway management is an essential skill for every pre-hospital clinician and should be performed to the same standards as would be expected in the emergency department. This chapter recommends tailored pre-hospital airway management in terms of clinical care delivered to the patient, skills of the clinician and the infrastructure of emergency medical system to achieve this. The importance of having a standardised, well-rehearsed approach, using aids to reduce cognitive load, articulating a clear airway management plan and having a structured way of handling airway management difficulties is highlighted. The concept of the physiologically difficult airway is discussed and the significance of excellent pre-oxygenation, peroxygenation, first-pass success and post-intubation care is discussed. Backup equipment in the form of second generation supraglottic airway devices, a videolaryngoscope with both standard and hyperangulated blades and equipment for an emergency front of neck airway should be available when advanced pre-hospital airway management is provided. When delivering airway management to trauma patients, an awareness of potential anatomical difficulties combined with careful management of physiological derangement is necessary to deliver safe, high quality care.
Introduction
The pathophysiology of the critically unwell or injured patient is the same in the pre-hospital setting as it is in the emergency department or intensive care unit. The requirement for high quality airway management is not dependent on the patient location.
The concepts described in other chapters are almost all applicable to pre-hospital patients. What then is different in the pre-hospital environment?
Pre-hospital clinicians see patients at an earlier point after injury or onset of serious illness and the signs and symptoms may therefore be less developed or more difficult to detect.
Although pre-hospital access to electronic patient charts are available in some areas, most pre-hospital clinicians have only limited information about a patient’s past medical history.
The emergency medical system (EMS) in many areas is multi-tiered, but the availability of backup is often limited, and may be a considerable distance away.
The amount of equipment available on scene is limited.
Patients in need of pre-hospital airway management in general, and pre-hospital advanced airway management (PHAAM) in particular, make up only a small percentage of the pre-hospital workload making airway management skill retention a challenge for some practitioners.
Tailored Care
Many pre-hospital services have structured standard operating procedures (SOPs) which dictate how anaesthesia and airway management is conducted. This contributes to predictable, high quality care.
However, this does not mean that ‘one size has to fit all’ and pre-hospital airway management can be tailored to patients, providers and the system delivering care.
Tailored Care: Patient Level
Before advanced airway intervention an informal risk–benefit assessment is made taking into account the condition and characteristics of the individual patient and the features of the pre-hospital situation in which they are. Typical features which may change management might include: the size and age of a patient, the presence of severe co-morbidities, airway abnormalities, access to the patient, a hazardous environment and the proximity to hospital.
Tailored Care: Clinician Level
Even with the development of pre-hospital training programmes and standardisation of advanced pre-hospital provider roles there is considerable variation in the experience and competences of providers, both between different professional groups and within them. Pre-hospital doctors may be trainee emergency physicians with the minimum anaesthetic training or consultant anaesthetists with many years of experience. Similarly, paramedics may have practised for many years at an advanced level or may have limited advanced airway skills. It is rare for pre-hospital practitioners to deliver anaesthesia frequently enough to remain competent without some in-hospital anaesthesia practice. The experience of the attending pre-hospital team may influence the decision to anaesthetise on scene.
Tailored Care: System Level
An EMS delivering PHAAM can tailor its activity by dictating what level of airway management is provided, for which patients and by what level of provider. Providers may be doctors, paramedics or nurses. The level of training and skill retention can be stipulated. The clinical governance of advanced airway management commonly lies with the ambulance service, an air ambulance or a hosting hospital. The EMS also has to consider the case mix and frequency of specific airway problems and how the evidence base for airway management should be applied to the population served. To provide the highest level of patient safety, the pre-hospital airway management offered by one EMS/helicopter emergency medical service (HEMS) may not be identical to that offered by another.
Human Factors
Using the combined knowledge of the entire team, empowering all team members to speak up when necessary and having a shared mental model is vital (see Chapter 36). In addition, we recommend the following in order to facilitate cognitive offloading and improve patient safety:
Airway management should be performed in a well-lit place with shelter and as close to 360° patient access as possible. Many services prefer to do this outside; but occasionally this may not be possible due to weather or other external factors.
A standardised equipment set-up should be used in every case (standard ‘kit dump’).
A standardised, well-rehearsed, pre-procedure checklist that has been tailored to the service guides preparation and delivery of pre-hospital anaesthesia. Having an unnecessarily long or impractical checklist reduces compliance and leads to checklist fatigue. Figures 30.1 and 30.2 show different tailored pre-rapid sequence intubation (RSI) checklists for two different doctor–paramedic staffed HEMS.
Regular simulations (or ‘moulages’) tailored to the needs of both the individual clinicians being ‘moulaged’ and the service should be used to practise the different components of airway management.
Figure 30.1 (b) immediate intubation checklist from the Emergency Medical Retrieval and Transfer Service, Wales.
Figure 30.1 (c) post RSI checklist from the Emergency Medical Retrieval and Transfer Service, Wales.
An in-hospital airway management expert does not necessarily translate to a pre-hospital airway management expert. The psychomotor skills of bag-valve-mask (BVM) ventilation, placing a supraglottic airway device (SGA) or tracheal intubation are transferable; the knowledge of where, when and how to use these skills in a less predictable environment may not be.
Data Collection
Pre-hospital services should record core data on airway intervention including timelines, success rates and complications. This enables service improvement and the identification of equipment, training and skill problems that require attention. Data may also be used to design and adapt service SOPs and be used by clinicians to inform decision making on-scene.
The Anatomically vs. Physiologically Difficult Airway
Anaesthetists often concentrate on the issues of difficult BVM ventilation, SGA placement and tracheal intubation. The difficulties of the anatomically difficult airway are also a routine consideration. These subjects are described in many other chapters.
The concept of a ‘physiologically’ difficult airway is more recent. The physiologically difficult airway has been described as one in which severe physiological derangements place the patient at increased risk for desaturation or cardiovascular collapse and death during intubation and the transition to positive pressure ventilation (see also Chapter 28).
In pre-hospital airway management this is as important as anatomical considerations. A significant proportion of patients have increased risks of desaturation or cardiovascular collapse during anaesthesia and airway management. Managing physiological considerations is essential in pre-hospital and trauma airway management to prevent potentially catastrophic hypotension, cardiac arrest or hypoxic brain injury.
Additional factors contributing to pre-hospital airway management difficulty include logistic difficulty (attributable to location, environment and equipment) and educational difficulty (lack of knowledge, training or preparation by the operator). A well-organised pre-hospital system should eliminate or minimise the impact of these.
The Practicalities of Pre-hospital Airway Management
The fundamental principle of good pre-hospital airway management is that it should be performed to the same standard and with the same level of patient safety as when performed in the emergency department or the intensive care unit. There are published recommendations on standards that should be achieved when delivering pre-hospital anaesthesia and advanced airway management from the UK, Scandinavia and the USA. All have a great deal in common.
Have a Plan
It is vital to have and to communicate both a plan and a backup plan. The plan should state intended techniques for addressing any problems which develop during the management of both anatomically and physiologically difficult airways after induction of anaesthesia.
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