, Amy Gospel2, Andrew Griffiths3 and Jeremy Henning4
Intensive Care Unit, James Cook University Hospital, Middlesbrough, UK
Tyne and Wear, UK
The York Hospital, Middlesbrough, UK
James Cook University Hospital, Middlesbrough, UK
By the end of this chapter you should:
Be familiar with the types and incidence of common complications associated with PHA
Be able to diagnose and manage the common adverse events during transfer
All interventions are associated with complications. Understanding the cause of these complications allows the operator to take steps to avoid them and this makes the procedure safer. The incidence of complications during pre-hospital anaesthesia (PHA) is difficult to establish from the current literature. It is likely that the reported absence of benefit from pre-hospital intubation in some studies may result from the complications during and after its performance. One study certainly suggested that an increased mortality was associated with pre-hospital hypotension and hyperventilation in head-injured casualties who underwent pre-hospital intubation (Davis et al. 2004). Other studies have demonstrated that the different make-up of teams and different ways of carrying out the technique make a huge difference – London HEMS report a failed intubation rate of only 0.25 % (Lockey et al. 2013) whilst other systems report rates up to 31 % (Cobas et al. 2009).
9.1.1 Immediate Complications (Box 9.1)
These result from the mechanical technique of laryngoscopy and intubation. Upper airway trauma to the teeth, pharynx, larynx, and trachea results from excessive force or improper use of the laryngoscope blade. This is often compounded when the intubation is difficult or hurried. Prolonged attempts at intubation expose patients to harmful physiological responses and increase the risk of hypoxia and aspiration (Mort 2004). An attempt to intubate should not normally exceed 45 s.
Box 9.1: Cause and Incidence of Immediate Complications
Upper airway trauma to the teeth, pharynx, larynx, trachea (Adnet et al. 1998)
Unrecognised Oesophageal intubation (Cobas et al. 2009)
Endobronchial intubation (Caruana et al. 2015)
Adults (Adnet et al. 1998)
Paediatrics (Easley et al. 2000)
Exacerbation of spinal cord injury (with MILS)
Increased risk of aspiration (Adnet et al. 1998)
Anaphylactic shock (Adnet et al. 1998)
Bronchospasm (Adnet et al. 1998)
Arrhythmias and bradycardia (Mort 2004)
Hypotension (Reid et al. 2004)
Cardiac arrest (Adnet et al. 1998)
Hypoxia (SpO 2 < 92 %)
9.1.2 Early Complications (Box 9.2)
These usually arise during transfer. The complications include endotracheal tube migration leading to accidental extubation or endobronchial or oesophageal intubation. One study reported 12 % of patients on arrival in hospital had unrecognised oesophageal intubations, although this was following non-drug assisted paramedic intubation (Cobas et al. 2009). Twisting of the endotracheal tube (ETT) or excessive cuff inflation pressures may lead to mucosal damage and an increased risk of subsequent tracheal stenosis. It is important to use a sterile endotracheal tube and ensure that it is kept as clean as possible during pre-hospital rapid sequence intubation (PRSI). Pre-hospital intubation is consistently reported as being associated with pneumonia later on in intensive care (von Elm et al. 2009).
9.1.3 Late Complications
These complications can arise as result of the severity of a patient’s injury or as a result of immediate or early complications during PRSI (Box 9.3).
Box 9.3: Late Complications
Hypoxic brain injury & multiorgan failure from hypoperfusion
Pneumonia (Eckert et al. 2004)
9.2 Adverse Events
It is difficult to estimate the incidence of adverse events in the anaesthetised patient during transfer to hospital, however it is unlikely to be less than the incidence during transfers within hospitals. Brunsveld-Reinders et al. (2015) reported a prospective study of transfers of critically ill patients from ICU to other hospital departments (typically for diagnostic procedures). One or more incidents were reported in 133 of 503 transfers (26 %). Many of these are relevant to pre-hospital transfer: hypotension, hypoxia, equipment malfunction, hypertension, cannula dislodgement, empty oxygen cylinder etc.
Too many critical incidents are related to human factors (39 %) or equipment failure (61 %) (Beckmann et al. 2004). These should be preventable with better Crew Resource Management (CRM) training and good equipment husbandry. The use of a checklist may also help (Brunsveld-Reinders et al. 2015).
There are two main adverse events that occur during transfer of a critically ill ventilated patient:
Hypoxia (low SpO2)
It is important to be able to rapidly recognise and manage the underlying problem causing either of these two events.
9.2.1 Hypoxia (Low SpO2)
It is essential to have an action plan to manage sudden patient desaturation (Appendix “Actions on Desaturation”).
First check whether the saturation probe is on a finger and has a normal trace. It is not uncommon for the probe to be hanging off the finger or on the floor/tucked in the blankets. Reposition the probe whilst continuing the assessment. If the probe is on and working, move straight on to find the problem.