Failed tracheal intubation in obstetric anaesthesia: 2 yr national case-control study in the UK.

BACKGROUND: There are few national figures on the incidence of failed tracheal intubation during general anaesthesia in obstetrics. Recent small studies have quoted a rate of one in 250 general anaesthetics (GAs). The aim of this UK national study was to estimate this rate and identify factors that may be predictors. METHODS: Using the UK Obstetric Surveillance System (UKOSS) of data collection, a survey was conducted between April 2008 and March 2010. Incidence and associated risk factors were recorded in consultant-led UK delivery suites. Units reported the details of any failed intubation (index case) and the two preceding GA cases (controls). Predictors were evaluated using multivariable logistic regression, significance P<0.05 (two-sided). RESULTS: We received 57 completed reports (100% response). The incidence using a unit-based estimation approach was one in 224 (95% confidence interval 179-281). Univariate analyses showed the index cases to be significantly older, heavier, with higher BMI, with Mallampati score recorded and score >1. Multivariate analyses showed that age, BMI, and a recorded Mallampati score were significant independent predictors of failed tracheal intubation. The classical laryngeal mask airway was the most commonly used rescue airway (39/57 cases). There was one emergency surgical airway but no deaths or hypoxic brain injuries. Gastric aspiration occurred in four (8%) index cases. Index cases were more likely to have maternal morbidities (P=0.026) and many babies in both groups were admitted to the neonatal intensive care unit: 21 (37%) vs 29 (27%) (NS). Three babies died--all in the control group.