NIHR Signal Pre-hospital intubation of people with serious head injuries by inexperienced staff linked to increased death rate

Published on 4 December 2015

This systematic review of patients with a serious head injury found that prehospital intubation by undertrained or inexperienced staff was linked to an increased risk of death when compared to no intubation or intubation after arrival in the hospital. Restoring an individual’s airway is a priority because lack of oxygen can cause death, brain damage and other negative outcomes, but prehospital intubation was not linked with a change in mortality generally.

Staff need to be trained in intubation and have regular refreshers to maintain their skills. It is not clear what proportion of emergency service personnel in the UK have such specialist training and therefore what, if any, additional resource would be required to ensure this level of experience was present across the workforce.

Pre-hospital intubation of people with serious head injuries by inexperienced staff linked to increased death rate

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Why was this study needed?

People with traumatic brain injury caused by a serious head injury can have a reduced level of consciousness, leading to their airway becoming blocked as muscles in the airway relax. Restoring the airway is a treatment priority because lack of oxygen can cause death, brain damage and other negative outcomes. The airway may be opened by simple techniques such as tilting the head back or removing obstructions manually. However, this is not always effective in people with serious head injuries.  In such cases a tube may be inserted through the mouth and into the windpipe to provide a clear airway before the person is taken to hospital. In the UK paramedics may have variable experience in performing intubation. As such the expertise of the practitioner could have an influence on the risk of adverse outcomes.

This systematic review aimed to look at the effects of intubation before hospital on mortality and whether the level of experience of the person performing the procedure had an effect on outcomes.

What did this study do?

This systematic review identified 24 trials (a total of over 30 000 patients); one randomised controlled trial, one secondary analysis of a randomised controlled trial and 22 cohort studies. In seven of the studies intubation was performed by an experienced provider, in five studies the provider’s experience was limited, and in 12 studies their level of experience was unclear.

The results of six of the studies (including a total of 4772 participants), where experience of the person intubating was clear and which also had a low risk of bias, were pooled in a meta-analysis.

The review looked only at “severe” traumatic brain injury, defined as a score of nine or less on the 15-point scale Glasgow Coma Scale accompanied by evidence of head injury. The age of participants in the included studies was 14 years or more; trials looking specifically at children were excluded. This review followed good practice for conducting systematic reviews, but many studies underlying the review were conducted in the US where paramedic standards and training may differ from the UK.

What did it find?

  • Overall there was no significant association between pre-hospital intubation and mortality (odds ratio [OR] 1.35, 95% confidence interval [CI] 0.78 to 2.33) when compared to no intubation or intubation on arrival in hospital.
  • Pre-hospital intubation by providers with limited experience was associated with significantly higher risk of mortality (OR 2.33, 95% CI 1.61 to 3.38). When it was performed by an experienced provider it was not associated with increased mortality (OR 0.75, 95% CI 0.52 to 1.08).

What does current guidance say on this issue?

NICE recommends that pre-hospital management of serious head injuries treats the greatest threat to life first. The guidance gives specific recommendations for when intubation should be performed immediately and before transfer, including when the person has a Glasgow Coma Scale of less than nine. NICE also recommends that initial assessment and care is in line with principles of best practice such as the Pre-hospital Trauma Life Support course and the Joint Royal Colleges Ambulance Service Liaison Committee Guidelines for Head Trauma. Guidelines produced by the Resuscitation Council recommend that pre-hospital intubation is only carried out by appropriately trained staff who undergo regular refreshers and suggest that another airway device (such as a laryngeal mask airway) may be preferable as it is easier to use.

What are the implications?

Compared to no intubation or intubation after arrival in hospital, pre-hospital intubation carried out by undertrained or inexperienced staff is associated with an increased risk of death. Even when performed by experienced staff it has no effect on mortality. The failure of intubation, even in experienced hands, to reduce mortality is an important finding. Current UK guidelines reflect the importance of a stepped approach to airway management with intubation reserved for those unable to maintain oxygenation by other means.

It is clear that this review may have training implications for the UK emergency response workforce, however the fact that most studies were conducted in the US, which has a different health system means that local information applicable to the NHS is required. This could include an assessment of the proportion of paramedics in the UK who have the required extensive experience and the potential costs of training more.

Bibliography

NICE. Head injury: Assessment and early management. CG176. London: National Institute for Health and Care Excellence; 2014.

RSUK. Adult advanced life support. London: Resuscitation Council (UK).

Why was this study needed?

People with traumatic brain injury caused by a serious head injury can have a reduced level of consciousness, leading to their airway becoming blocked as muscles in the airway relax. Restoring the airway is a treatment priority because lack of oxygen can cause death, brain damage and other negative outcomes. The airway may be opened by simple techniques such as tilting the head back or removing obstructions manually. However, this is not always effective in people with serious head injuries.  In such cases a tube may be inserted through the mouth and into the windpipe to provide a clear airway before the person is taken to hospital. In the UK paramedics may have variable experience in performing intubation. As such the expertise of the practitioner could have an influence on the risk of adverse outcomes.

This systematic review aimed to look at the effects of intubation before hospital on mortality and whether the level of experience of the person performing the procedure had an effect on outcomes.

What did this study do?

This systematic review identified 24 trials (a total of over 30 000 patients); one randomised controlled trial, one secondary analysis of a randomised controlled trial and 22 cohort studies. In seven of the studies intubation was performed by an experienced provider, in five studies the provider’s experience was limited, and in 12 studies their level of experience was unclear.

The results of six of the studies (including a total of 4772 participants), where experience of the person intubating was clear and which also had a low risk of bias, were pooled in a meta-analysis.

The review looked only at “severe” traumatic brain injury, defined as a score of nine or less on the 15-point scale Glasgow Coma Scale accompanied by evidence of head injury. The age of participants in the included studies was 14 years or more; trials looking specifically at children were excluded. This review followed good practice for conducting systematic reviews, but many studies underlying the review were conducted in the US where paramedic standards and training may differ from the UK.

What did it find?

  • Overall there was no significant association between pre-hospital intubation and mortality (odds ratio [OR] 1.35, 95% confidence interval [CI] 0.78 to 2.33) when compared to no intubation or intubation on arrival in hospital.
  • Pre-hospital intubation by providers with limited experience was associated with significantly higher risk of mortality (OR 2.33, 95% CI 1.61 to 3.38). When it was performed by an experienced provider it was not associated with increased mortality (OR 0.75, 95% CI 0.52 to 1.08).

What does current guidance say on this issue?

NICE recommends that pre-hospital management of serious head injuries treats the greatest threat to life first. The guidance gives specific recommendations for when intubation should be performed immediately and before transfer, including when the person has a Glasgow Coma Scale of less than nine. NICE also recommends that initial assessment and care is in line with principles of best practice such as the Pre-hospital Trauma Life Support course and the Joint Royal Colleges Ambulance Service Liaison Committee Guidelines for Head Trauma. Guidelines produced by the Resuscitation Council recommend that pre-hospital intubation is only carried out by appropriately trained staff who undergo regular refreshers and suggest that another airway device (such as a laryngeal mask airway) may be preferable as it is easier to use.

What are the implications?

Compared to no intubation or intubation after arrival in hospital, pre-hospital intubation carried out by undertrained or inexperienced staff is associated with an increased risk of death. Even when performed by experienced staff it has no effect on mortality. The failure of intubation, even in experienced hands, to reduce mortality is an important finding. Current UK guidelines reflect the importance of a stepped approach to airway management with intubation reserved for those unable to maintain oxygenation by other means.

It is clear that this review may have training implications for the UK emergency response workforce, however the fact that most studies were conducted in the US, which has a different health system means that local information applicable to the NHS is required. This could include an assessment of the proportion of paramedics in the UK who have the required extensive experience and the potential costs of training more.

Bibliography

NICE. Head injury: Assessment and early management. CG176. London: National Institute for Health and Care Excellence; 2014.

RSUK. Adult advanced life support. London: Resuscitation Council (UK).

Experience in Prehospital Endotracheal Intubation Significantly Influences Mortality of Patients with Severe Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Published on 27 October 2015

Bossers, S. M.,Schwarte, L. A.,Loer, S. A.,Twisk, J. W.,Boer, C.,Schober, P.

PLoS One Volume 10 , 2015

BACKGROUND: Patients with severe traumatic brain injury (TBI) are at high risk for airway obstruction and hypoxia at the accident scene, and routine prehospital endotracheal intubation has been widely advocated. However, the effects on outcome are unclear. We therefore aim to determine effects of prehospital intubation on mortality and hypothesize that such effects may depend on the emergency medical service providers' skill and experience in performing this intervention. METHODS AND FINDINGS: PubMed, Embase and Web of Science were searched without restrictions up to July 2015. Studies comparing effects of prehospital intubation versus non-invasive airway management on mortality in non-paediatric patients with severe TBI were selected for the systematic review. Results were pooled across a subset of studies that met predefined quality criteria. Random effects meta-analysis, stratified by experience, was used to obtain pooled estimates of the effect of prehospital intubation on mortality. Meta-regression was used to formally assess differences between experience groups. Mortality was the main outcome measure, and odds ratios refer to the odds of mortality in patients undergoing prehospital intubation versus odds of mortality in patients who are not intubated in the field. The study was registered at the International Prospective Register of Systematic Reviews (PROSPERO) with number CRD42014015506. The search provided 733 studies, of which 6 studies including data from 4772 patients met inclusion and quality criteria for the meta-analysis. Prehospital intubation by providers with limited experience was associated with an approximately twofold increase in the odds of mortality (OR 2.33, 95% CI 1.61 to 3.38, p<0.001). In contrast, there was no evidence for higher mortality in patients who were intubated by providers with extended level of training (OR 0.75, 95% CI 0.52 to 1.08, p = 0.126). Meta-regression confirmed that experience is a significant predictor of mortality (p = 0.009). CONCLUSIONS: Effects of prehospital endotracheal intubation depend on the experience of prehospital healthcare providers. Intubation by paramedics who are not well skilled to do so markedly increases mortality, suggesting that routine prehospital intubation of TBI patients should be abandoned in emergency medical services in which providers do not have ample training, skill and experience in performing this intervention.

Expert commentary

This review adds to the growing evidence that what has been regarded as the ‘gold standard’ of airway management, namely tracheal intubation, is not all that it seems. Tracheal intubation requires a significant amount of initial training and on-going experience in order to be able to deliver the skill safely and effectively, particularly in the challenging pre-hospital environment. The finding that intubation undertaken by those with limited skills harms patients, is an important and timely study.

The recent Resuscitation Council (UK) 2015 pre-hospital guidelines that now advocate a stepwise approach to paramedic airway management are reinforced by these findings. These suggest that paramedics aim to do no more than is necessary to achieve an open airway through which adequate oxygenation and gas exchange can occur. Pre-hospital EMS systems should take note of these findings and ensure that the delivery of airway management is matched to the skills of their providers.

Professor Charles D Deakin, Honorary Professor of Resuscitation and Pre-Hospital Emergency Medicine, University of Southampton