There has been much controversy over the management of the prehospital airway and the issue of who should intubate a patient
requiring sedation. In Australia, each state has its own ambulance service and there is no agreement on this issue. In some states, there are retrieval doctors who attend the cases where intubation may be required, especially in the setting of trauma.
In one state, road and helicopter intensive care paramedics are authorized to give sedation and paralysis to facilitate rapid sequence intubation.
Most states do not allow paramedics to paralyze patients in the field—leading to the potential for large doses of narcotic to be administered in combative brain trauma patients, in order to perform laryngoscopy. Hypotension and hypoxaemia are often the result.
Current literature confirms that there is still a great deal of debate around the issue of prehospital intubation, especially in the setting of acute traumatic brain injury. A failure to intubate rate of 31% in patients who had an attempted prehospital intubation by paramedics prior to arrival at a level 1 trauma centre, has recently been reported (Cobas et al, 2009).
This is similar to work carried out by Katz and Falk who demonstrated a 25% incidence of misplaced tubes on emergency department arrival (2001). This compares with figures as high as 99% successful intubation in the prehospital setting when performed by physicians (Adnet et al, 1998). It is questionable to accept a ‘success’ rate of anything less than 95%. Interestingly, a recent systematic Cochrane review showed no benefit from prehospital intubation in patients with traumatic brain injury (Von Elm et al, 2009).
Training to look after the airway
The issue is probably not who should be looking after the airway—rather it is the qualification and training that that person has received. The training to perform a laryngoscopy is not only what is required—it is the ability to assess an airway and decide on the best management plan and to be competent to follow this plan through with enough clinical acumen to have a backup plan if necessary.
The irony appears to be that patients with traumatic brain injury are often the most difficult patients to manage, yet we leave their difficult airway management to those who have the least experience. Possible cervical spine injury, often with other co morbidities complicated by trismus, entrapment and exposure to the elements, is a familiar scene to many paramedics.
However, the average paramedic in Australia only performs 1-2 intubations per year. Participation in a two day course to learn about pharmacology of paralysing drugs and anaesthetic agents with a multiple choice examination at the end is hardly a robust system. Failure rates for successful intubation in paramedics who were taught in this manner are consistently high.
This debate is complicated by the fact that there is currently a nationwide shortage of anaesthetists and doctors in general, in Australia.
The situation in Australia
Many paramedics work in rural areas remote from major hospitals with community volunteer support in the field. This has led, in the past, to proposals to increase the training of a small group of paramedics to perform rapid sequence to prevent skill dilution.
Skill dilution is the inevitable outcome since we have a small population relative to the land area covered. It is preferable for 10 paramedics to do 10 intubations annually, rather than 100 paramedics to perform one per year. Despite this, there has been a recent decision to allow road–based paramedics to perform rapid sequence intubation in certain states without addressing this lack of experience (Ambulance Victoria, 2009). More worrying is the issue of no formal skill maintenance programme or mandatory auditing of outcomes and morbidity.
Although all services have the ability to perform quality assurance appraisals, the audit is usually carried out internally by paramedics themselves. Only if a paramedic is concerned about a colleagues handling of a case, is it referred to a medical officer (also internal to the service). Many cases lack any detail of saturations or blood pressures during these high risk manoeuvres in high risk brain injury patients. This is due to the lack of real-time monitoring in ambulances and the requirement to retrospectively fill in data after the intubation.
Many critical events may not be registered or appreciated during the intubation itself. Manual blood pressure monitoring, for example, is never performed during the laryngoscopy—thus hypotension/hypertension is unlikely to be reported.
Reports from literature
It has been reported that approximately 60 intubations are required before anaesthetic registrars have a 90% success rate with intubation (Spaite and Criss, 2003). Few ambulance services mandate minimum numbers of intubations per year (or keep records of them) nor have a maintenance of professional standards programme. The Joint Royal Colleges Ambulance Liaison Committee Airway Working Group (JRACLC AWG) recently concluded:
‘There is also evidence that the current initial training of 25 intubations performed in-hospital is inadequate, and the lack of ongoing intubation practice may compound this further. Supraglottic devices (laryngeal mask airways), which were not available when extended training and paramedic intubation was introduced, are now in use in many ambulance services and are a suitable alternative prehospital airway device for paramedics.’
This level of airway experience would not be tolerated in the public hospital system where registrars have to be supervized for several years before being allowed to do unsupervized rapid sequence intubations in otherwise uncomplicated cases. An editorial published in 2003 (Spaite and Criss, 2003) commented on the sparsity of published complications and outcomes in the prehospital setting. This accompanied an article citing a 57% incidence of desaturation accompanying RSI reported by Dunford et al (2003). Secondary brain injury is usually the outcome when hypotension and hypoxia accompany a difficult intubation. These are common, yet rarely documented, events in the traumatic brain injury patient that require sedation to intubate.
A prospective multicentre study in California showed the following results in 150 patients enrolled looking at prehospital hypoxic events:
Fifty seven patients had at least one secondary injury; 37 had only hypoxic episodes, 14 had only hypotensive episodes, and 6 patients had both. The mortality for patients without secondary injury was 20%, compared with 37% for patients with hypoxic episodes. The Disability Rating Scale score at discharge was significantly higher in patients with secondary insults. Using multivariate analysis, the calculated odds ratio of mortality caused by prehospital hypoxia after head injury was 2.66 (p<0.05) (Chi et al, 2006).
The need for addressing skill set and experience
Traumatic brain injury (TBI) is common and, when severe, has a poor outcome. It is a huge health and economic burden for society. It is estimated from American studies that traumatic brain injury costs more than US$ 1.67 million per 100 000 population. Lost productivity due to TBI mortality is estimated to be approximately US$ 18.8 million per 100 000 population (Rochette et al. 2009).
This supports a strong case for a cost-effective strategy to address the skill set and experience of the person handling the airway in the prehospital setting. Whether this is a doctor or a paramedic is not the issue,—the issue is an appropriately trained and experienced person.
Once paralysis is given to a previously spontaneously breathing patient, there is an onus on providing adequate ventilation to that patient. Ventilation and oxygenation should always be the goal, not intubation at all costs.
Intubation for rural situations
Tasmanian Ambulance assessed the literature regarding the safety of prehospital drug assisted intubation for difficult to manage, rural trauma situations. The outcome of this literature search did not support the introduction of RSI and legitimate concerns were raised regarding individual practitioners' low exposure to intubation and lack of formal process to maintain skills.
This led to the suggestion of drug assisted airway management using the intubating laryngeal mask airway (ILMA) in this group of patients. Changing the focus from intubation to ventilation as a strategy in prevention of traumatic brain injury was the goal. The ILMA had already been introduced to the service and all paramedics in Tasmania were trained in its use (McCall et al, 2008). The Tasmanian Ambulance services a population of 500 000 people, almost half of which live in rural and often remote terrain.
The author calculated in 2010, that the cost of implementing a suitable skills programme for helicopter retrieval paramedics to perform paralysis assisted ILMA insertion, including ongoing skills maintenance and medical oversight, would cost the Tasmanian Ambulance Service AUS$ 860 000 over three years. The proposal to introduce RSA was endorsed by the Tasmanian Clinical Council of Tasmanian Ambulance Services but has not been implemented due to lack of resources (both financial and clinical).
Rapid sequence intubation with paralysis
Rapid sequence intubation with paralysis requires a higher skill set than paralysis for insertion of an ILMA. The insertion of an ILMA automatically changes the focus to one of oxygenation and ventilation. It still allows intubation to be considered or attempted via the device. The programme includes formalized in-hospital regular supervized intubations with mandatory log books and annual reaccreditation, via simulation sessions and airway workshops run by medical officers with close medical supervision and an audit of complications.
Annual ongoing costs of the programme would probably be approximately AUS$ 50–100 000 per year depending on the number of paramedics that had not gained enough on–road experience and consequently would need more in-hospital time (in order to achieve the 10 annual intubations required).
Training on real patients
Time for training on real patients with an experienced anaesthetist needs to be factored in if paramedics do not have ten advanced (successful) airways logged per annum. This may require one dedicated day in an operating room per year. Wang and Yeally have commented on the importance of real patient practice sessions:
‘Previous efforts to implement field RSI have focused extensively on providing supplemental training in invasive airway management skills and have even required practice on live operating room patients. Many clinicians feel that additional operating room training using live patients is a mandatory component of an RSI program, and this sentiment has been echoed in The National Association of EMS Physicians' position statement on out-of-hospital RSI. Although mannequins may help to simulate the basic motions of laryngoscopy, current training models (including state-of-the-art human simulators) cannot yet reproduce the subtle yet profound anatomic and physiologic effects resulting from paralytic administration; they are not adequate substitutes for training on live human beings.’
This strategy requires close cooperation between the ambulance service to allow officers to attend hospital training sessions; medical officers/ hospital administrators to ensure real airway experience
exposure, and the government to fund training sessions. There must be willing medical staff who support the concept of teaching these skills.
The proposed RSA clinical practice guideline for Tasmanian Ambulance officers is essentially the same as their current guideline for using the intubating laryngeal mask for airway management with the additional strict protocols for drug doses of midazolam, fentanyl and suxamethonium.
The hypnotic doses are based on vital signs of the patient and are written in the same format as other paramedic flow charts for medical conditions requiring drug dosage titration. The rapid sequence airway protocol is proposed only for use in patients with head trauma with difficulty maintaining ventilation due to trismus.
Failure to ventilate
The most contentious part of our failure to intubate/ventilate algorithm was in deciding that laryngoscopy was not to be used. Many paramedics questioned why they could not just have a look once the suxamethonium had been given. This would have turned the situation into a RSI (rapid sequence intubation) rather than a RSA (rapid sequence airway). The whole point of the exercise was to simplify airway management and to break the mindset of ‘must intubate'. The focus of our strategy was to create a mindset of ‘must ventilate'.
Once paralysis has been given, there should be no delay in providing ventilation. If this is not possible through the ILMA, a normal LMA (which is less bulky) should be placed and if this is also unsuccessful, then BVM should be started. It wastes valuable time to attempt laryngoscopy in this scenario and gains little. It is unlikely that a patient who is difficult to ventilate with a LMA is going to have a grade 1–2 layngoscopy.
The ILMA has been repeatedly shown to be easier to use and maintain skills with, compared to, conventional intubation with a laryngoscope. In the hands of an occasional intubator a laryngoscopy in the midst of a failed ventilation scenario can lead to disaster. Avoidance of hypoxaemia is essential if secondary brain injury is to be avoided. As is the case in all failure to ventilate algorithms, it ends with a cricothyroidotomy.
The ability to intubate patients with suspected cervical spine injury without neck extension was one of the reasons the ILMA was developed and introduced. It is a common and accepted method of intubating the head trauma patient in the operating room prior to neurosurgery. It has also been used in the prehospital setting by emergency physicians in difficult intubations (Baude e al, 2006; Timmermann et al, 2007).
Resistance to use ILMA
The author has had some paramedics express that they feel threatened that the skill of intubation may be taken away from them altogether if ILMA is introduced to head injured trauma patients. They see the beginning of an erosion of skills that they have been able to use for decades. Interestingly, the recent ILCOR (International Liaison Committee on Resuscitation) recommendations make a focus on the consideration of supraglottic airway devices to be used in cardiac arrests rather than intubation. They state:
‘There is insufficient evidence to support or refute the use of any specific technique to maintain an airway and provide ventilation in adults with cardiopulmonary arrest. Despite this, tracheal intubation is perceived as the optimal method of providing and maintaining a clear and secure airway. It should be used only when trained personnel are available to carry out the procedure with a high level of skill and confidence. A recent systematic review of randomised controlled trials (RCTs) of tracheal intubation versus alternative airway management in acutely ill and injured patients identified just three trials (Lecky et al,2008): two were RCTs of the Combitube versus tracheal intubation for out-of-hospital cardiac arrest, which showed no difference in survival. The third study was a RCT of prehospital tracheal intubation versus management of the airway with a bag-mask in children requiring airway management for cardiac arrest, primary respiratory disorders and severe injuries.’ (Gauche et al, 2000).
‘There was no overall benefit for tracheal intubation; on the contrary, of the children requiring airway management for a respiratory problem, those randomized to intubation had a lower survival rate that those in the bag-mask group. The Ontario Prehospital Advanced Life Support (OPALS) study documented no increase in survival to hospital discharge when the skills of tracheal intubation and injection of cardiac drugs were added to an optimised basic life support-automated external defibrillator (BLSAED) system.
In simulation trauma settings, there is a strong desire to be ‘doing something’ even when it is an undesirable action and may in fact cause patient harm. This causes people to focus on tasks (e.g. intubation) rather than the patient (e.g. is the patient breathing adequately?).
The resistance to prehospital use of the ILMA is difficult to justify. A review by Nolan (2001) pointed out that the preference for tracheal intubation in the prehospital setting has been based on the notion that a cuffed tube will protect the lungs from aspiration. The independent contribution of aspiration in this setting to outcome is unknown (Lawes and Baskett, 1987).
It has been suggested that the risk of aspiration with a laryngeal mask airway may have been overstated (Brimacombe et al. 1995; David et al, 2007). In fact, in this group of patients, aspiration may already have occurred long before paramedics have arrived on scene. The consensus opinion from a specialist panel of experts on the topic of paramedic rapid sequence intubation for severe brain injury stated the following opinion:
‘System differences in initial RSI training and skills maintenance may account for some of the variability in success with the procedure. Relatively small groups of highly trained paramedics who perform RSI with sufficient frequency to maintain a skill level comparable with in hospital providers can perform prehospital RSI’
They also qualify this by the statement:
‘A paramedic RSI programme requires a supportive infrastructure that includes strong medical direction and oversight, protocol development, an implementation plan that includes cognitive and technical training, appropriate prehospital triage, skill maintenance, and performance improvement. Paramedic RSI should not be performed in EMS systems where provider training is limited to brief introductory experiences, procedural exposure is low, and/or advanced monitoring is unavailable’
Given appropriate financial resources, Tasmanian Ambulance can implement a safer strategy to manage traumatic brain injury airways and reduce the risk of secondary brain injury. It depends on government resources. There has been a trend for governments to recognize the benefit of prevention strategies for costly diseases, so we await the final decision on funding the training.
The bottom line is the patient deserves the same level of care in the prehospital environment as they do in the emergency department. This requires a select group of paramedics having as robust a training system as that of the receiving medical staff.
Conclusion
Healthcare personnel who undertake prehospital intubation should do so only within a structured, monitored programme, which should include comprehensive competency-based training and regular opportunities to refresh skills. It is because paralysis assisted intubation requires greater skill and numbers to ensure competency that ILMA insertion should be considered in the setting of head injury. ILMA insertion is easier to teach and maintain competency with and has advantages over intubation in the setting of head trauma (no cervical spine movement). Introduction of drugs causing paralysis raises the stakes of ensuring ventilation can be achieved rapidly and safely.