Notice: You are viewing an unstyled version of this page. Are you using a very old browser? If so, please consider upgrading

Failed Intubation

Research questions

  • What is the UK incidence of failed intubation for obstetric general anaesthesia?
  • What are the risk factors for failed intubation for obstetric surgery?
  • How is failed intubation managed?
  • What are the maternal outcomes after failed intubation?
  • What are the neonatal outcomes after failed intubation?


Reports from the Confidential Enquiries into Maternal Deaths have shown a decrease in the number of anaesthetic related deaths over recent years[1]. However, a consistent cause of death is hypoxia relating to a failure to intubate and ventilate. The incidence of failed intubation among the pregnant population is estimated to be up to 8 times that of the non-pregnant population[2][3], but, as yet, no national data exist.

The reasons for this higher incidence in the obstetric population are multiple. Anatomical changes in the airway due to physiological changes in pregnancy have been noted[4]. Additionally, the physiological changes of a reduced functional residual capacity and an increased metabolic rate in pregnancy lead to a rapid progression to hypoxia following induction and apnoea. This adds pressure on the anaesthetist to intubate quickly before desaturation occurs. These issues are compounded by the fact that obstetric surgical procedures are now less frequently performed under general anaesthesia, so that training opportunities for junior anaesthetists are becoming more rare[5]. The procedures are also frequently required "out of hours" when the trainee anaesthetist is likely to be not to be working under direct supervision. Also, the amount of time spent in training is reduced overall[6].

Study size

The study will aim to collect data on 140 cases and 280 controls over two years.

Case definition

Any woman of over 20 weeks gestation given a general anaesthetic (whether on delivery suite or another hospital department) where a failed intubation has occurred.

Failed intubation is defined as failure to achieve tracheal intubation during a rapid sequence induction for obstetric anaesthesia, thereby initiating a failed intubation drill.


Obstetric Anaesthetists Association (OAA).

Ethics approval

The study has been approved by the London MREC (study ref 08/H0718/1).


David Milne, Audrey Quinn, Amanda Pinder, Heather Gorton
Leeds General Infirmary

Download the Data Collection Form (DCF)

UKOSS Failed Intubation Form


  1. ^ Lewis G. (Ed). The Confidential Enquiry into Maternal and CHild Health (CEMACH). Saving Mothers Lives: reviewing maternal deaths to make childhood safer - 2003-2005. London: CEMACH, 2007.
  2. ^ Rahman K, Jenkins JG. Failed tracheal intubation in obstetrics: no more frequent but still managed badly. Anaesthesia 2005; 60: 168-71.
  3. ^ Hawthorne I, Wilson R, Lyons G, Dresner M. Failed intubation revisited: 17-yr experience in a teaching maternity unit. British Journal of Anaesthesia 1996; 76: 680-4.
  4. ^ Pilkington S, Carli F, Dakin MJ, et al. Increase in Mallam-pati score during pregnancy. British Journal of Anaesthesia 1995; 74: 638-42.
  5. ^ Johnson RV, Lyons GR, Wilson RC, Robinson AP. Training in obstetric general anaesthesia, a 'vanishing art'? Anaesthesia 2000; 55: 712-3.
  6. ^ Sim DJ, Wrigley SR, Harris S. Effects of the European Working Time Directive on anaesthetic training in the United Kingdom. Anaesthesia 2004; 59: 781-84.

Updated: Tuesday, 17 January 2023 17:41 (v5)

Contact us

For more information about UKOSS, please view the contact details page