Self-positioning followed by induction of anaesthesia and insertion of a laryngeal mask airway versus endotracheal intubation and subsequent positioning for spinal surgery in the prone position: a randomised clinical trial.

BACKGROUND: Anaesthesia followed by positioning in the prone position takes time and may have complications.

OBJECTIVE: The hypothesis was that self-positioning in the prone position followed by anaesthesia and introduction of a laryngeal mask airway (LM method) would be faster with fewer complications than positioning after tracheal intubation (ET method).

DESIGN: Randomised, controlled trial.

SETTING: University Hospital, March 2009 to March 2011.

PATIENTS: One hundred forty patients scheduled for spinal surgery were allocated to the LM or the ET method. Exclusion criteria were surgery expected to last more than 2 h, American Society of Anesthesiologists status more than II, age more than 70 years, abnormal neck, throat, and mouth anatomy and function, Mallampati score III-IV, BMI more than 35 kg m, anticipated difficult airway/mask ventilation and decreased neck mobility.

INTERVENTIONS: Patients in the LM group placed themselves in the prone position, anaesthesia was induced and a laryngeal mask was introduced. Patients in the ET group were anaesthetised, intubated and then placed in the prone position.

MAIN OUTCOME MEASURES: Time taken from identification of the patient at the outset to readiness for radiographic examination following anaesthesia and positioning. Airway problems, sore throat, hoarseness and pain from muscles and joints were also noted.

RESULTS: One hundred and forty patients were randomised to LM (n = 70) and ET (n = 70). Data from 64 and 67 patients were analysed. Values are expressed as median (interquartiles) [range]. The primary outcome time was 25 min (23 to 29) [16 to 44] in the LM group and 30 min (26 to 33) [17 to 47] in the ET group (P <0.001). In two patients in group LM, a complete seal could not be obtained; one was intubated, and the other had surgery cancelled due to arterial hypotension. There were fewer cases with sore throat, hoarseness and pain from muscles and joints in the LM group at 3 h, but not at 24 h postoperatively.

CONCLUSION: Self-positioning and induction of anaesthesia in the prone position saves time. More patients should be studied to confirm safety and examine whether the method reduces the number of severe complications associated with the prone position.

TRIAL REGISTRATION: www.clinicaltrials.gov identifier: NCT01041352.