Research Paper On Intubation

  1. David Lockey(djl99{at}hotmail.com), fellow in prehospital care,
  2. Gareth Davies, consultant in accident and emergency and prehospital care,
  3. Tim Coats, senior lecturer
  1. Department of Accident and Emergency, Royal London Hospital, London E1 1BB
  1. Correspondence to: D Lockey

In the United Kingdom, it is current practice for paramedics to perform tracheal intubation on trauma patients when the airway is compromised and basic airway manoeuvres have failed. Paramedics in Britain never use anaesthetic drugs or muscle relaxants to achieve intubation.

Anecdotal experience shows that patients who can be intubated without the use of drugs have a poor prognosis. We investigated mortality in a population of trauma patients who were intubated before reaching hospital without anaesthetic drugs being used.

Participants, methods, and results

We looked retrospectively at the database of a helicopter emergency medical service staffed by doctors and paramedics that is specifically targeted at trauma patients in a mainly urban area. We identified patients who had been intubated without drugs by paramedics or doctors, and we recorded whether they survived to hospital discharge. All patients were attended by physicians, but many of the patients were intubated by ground crew paramedics before the medical team arrived. Patients were taken to the nearest appropriate hospital by ground or air.

In a six year period, from January 1990 to December 1996, 1623 patients were intubated outside hospital. Of these, we excluded 143 (8.8%) because they were not trauma patients. Of the remaining 1480 patients, 492 (33.2%) were intubated without drugs: 275 (55.8%) by physicians and 216 (43.9%) by paramedics. Data regarding survival were not available for six of these patients, but of the remaining 486 patients, one (0.2%) survived. This person had a cardiac arrest after penetrating chest trauma and underwent a thoracotomy on scene to relieve pericardial tamponade and suture the myocardium.

Comment

As almost all the trauma patients intubated without the use of drugs died, the value of this practice is doubtful. To allow easy passage of a tracheal tube without anaesthetic drugs, a patient must be profoundly unconscious, and a high likelihood of death might be expected. Despite this expectation, it was surprising that the outcome was almost always fatal.

Paramedics in Britain have been intubating without the use of anaesthetic drugs for more than 20 years, and many resources have been invested in teaching the skill. This intervention was introduced mainly to improve outcome following medical (non-traumatic) cardiac arrest, but recently the effectiveness of intubation in this situation has been questioned.1 In patients with severe trauma, airway compromise is a cause of prehospital death that can be prevented2 and simple airway manoeuvres can clear the airway to provide vital oxygenation.

Laryngoscopy and attempted intubation without drugs have potential risks, such as an increase in intracranial pressure, vomiting, and unrecognised oesophageal intubation.3 Some trauma systems use drugs to facilitate prehospital intubation—this is standard practice for paramedics and nurses in parts of the United States—but even if drugs are used, failed intubation rates can be high.4

There is little evidence about the optimum prehospital management of severe blunt injury, and there are no controlled trials of the different methods of airway management. As the role of the UK paramedic is under discussion5 and there are few data from the United Kingdom about the rate of failed prehospital intubation in trauma patients, the use of non-drug assisted intubation deserves further scrutiny.

Acknowledgments

Contributors: DL, GD, and TC conceived the idea for the study. DL collected the data and wrote the paper. The paper was discussed, revised, and edited by DL, GD, and TC. DL is the guarantor of the paper.

Footnotes

  • Funding None declared.

  • Competing interests None declared.

  • This article is part of the BMJ's randomised controlled trial of open peer review. Documentation relating to the editorial decision making process is available on the BMJ's website

References

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Abstract

Introduction

Since anesthesia complications associated with unexpected difficult airway are potentially catastrophic, they should be avoided. The modified Mallampati test and jaw-thrust maneuver enable the identification of difficult airway. The aim of this study was to associate the modified Mallampati test and the jaw-thrust maneuver with laryngoscopy (Cormack–Lehane) in an attempt to identify a better predictor of difficult airway in an adult population undergoing elective surgery.

Method

A cross-sectional study in which 133 adult patients undergoing elective surgery requiring tracheal intubation were analyzed. The accuracy and specificity of the modified Mallampati test and jaw-thrust maneuver were assessed by correlating them with difficult laryngoscopy (Cormack–Lehane Degrees 3 and 4).

Results

In the 133 patients evaluated the difficult intubation rate found was 0.8%; there was association between the two predictive tests proposed (p = 0.012). The values of 94.5% for specificity and 95.4% for accuracy were found for the jaw-thrust maneuver and for the modified Mallampati test, the values found were 81.1% and 81.2%, respectively. Kappa agreement identified a result of 0.240 between jaw-thrust maneuver and Cormack–Lehane, which was considered reasonable. On the other hand, a poor agreement (κ = 0.06) was seen between modified Mallampati test and Cormack–Lehane test.

Conclusion

The jaw-thrust maneuver presented superior accuracy and agreement than the modified Mallampati test, showing the ability to identify a difficult airway. It is necessary to emphasize the association of tests in the evaluation of patients, emphasizing their complementarity to minimize the negative consequences of repeated laryngoscopies.

Resumo

Introdução

As complicações anestésicas associadas às vias aéreas difíceis inesperadas por serem potencialmente catastróficas devem ser evitadas. O teste de Mallampati modificado e a manobra de protrusão mandibular possibilitam a identificação da via aérea difícil. O objetivo deste estudo foi associar o teste de Mallampati modificado e a manobra de protrusão mandibular com a laringoscopia (Cormack-Lehane) e tentar identificar um melhor preditor de via aérea difícil na população adulta submetida à cirurgia eletiva.

Método

Estudo corte transversal, foram analisados 133 pacientes adultos submetidos a cirurgias eletivas que necessitavam de intubação orotraqueal. Avaliaram-se a acurácia e especificidade do teste de Mallampati modificado e da manobra de protrusão mandibular, correlacionados com laringoscopia difícil (Cormack-Lehane Graus 3 e 4).

Resultados

Entre os 133 pacientes avaliados, a taxa de intubação difícil encontrada foi 0,8%, houve associação entre os dois testes preditores propostos (p = 0,012). Foram encontrados os seguintes valores para a especificidade 94,5% e a acurácia 95,4% na manobra de protrusão mandibular. Já para o teste de Mallampati modificado valores de 81,1% e de 81,2% respectivamente. A análise de concordância Kappa identificou entre manobra de protrusão mandibular e Cormarck-Lehane um resultado de 0,240; considerado razoável. Por outro lado, observou-se uma fraca (κ = 0,06) concordância entre o teste de Mallampati modificado e o Cormarck-Lehane.

Conclusão

A manobra de protrusão mandibular apresentou acurácia e concordância superiores ao teste de Mallampati modificado, mostrou a capacidade de identificar uma via aérea difícil. Faz-se necessário enfatizar a associação dos testes na avaliação do paciente, destacar a complementariedade deles, minimizar as consequências negativas de laringoscopias repetidas.

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