A comparison of three types of tracheal tube for use in laryngeal mask assisted blind orotracheal intubation.

Laryngeal mask assisted blind orotracheal intubation is a technique that is best mastered under controlled circumstances. The influence of the type of tracheal tube, and positioning of the head, on the success rate of this procedure was evaluated in 90 gynaecological patients presenting for elective procedures under general anaesthesia. After induction, a laryngeal mask was introduced and its position was confirmed. Up to three attempts at blind orotracheal intubation using one of three tracheal tubes (Argyle, Portex or Kendall Curity) passed through the laryngeal mask were permitted in each patient. The success rates after a single attempt at blind oral intubation were 3.3%, 70.0% and 30.0% respectively (p < 0.001 and p < 0.05 when Portex was compared to Argyle and Kendall Curity types). After a maximum of three attempts, success rates were 30.0% (Argyle), 93.3% (Portex) and 76.7% (Kendall Curity). The first attempt at tracheal intubation was performed in the 'sniffing the morning air position' and this was successful in 52% of successful intubations; the second attempt using extension at the atlanto-occipital joint was successful in a further 35% of successful intubations; the third attempt used varying degrees of neck flexion and extension at the atlanto-occipital joint and this permitted successful placement of the tracheal tube in the remaining 13% of patients in whom tracheal intubation was possible.