Predictors of LMA Failure

Chang-Ho Chon, DO

Article:
Predictors and Clinical Outcomes from Failed Laryngeal Mask Airway Unique^TM

Ramachandran, Satya K., et al. Anesthesiology. June 2012 – Vol 116 – No. 6, pp 1217-26

Summary:

The reported rate of failure with use of supraglottic airway devices is 0.2-8%. However, little is known about the risk-adjusted prediction of LMA failure requiring rescue tracheal intubation and its impact on patient outcomes.

This prospective study included 15,795 adult (³18 yr) undergoing general anesthesia at a University of Michigan affiliated quaternary care facility with the use of the LMA Unique^TM (uLMA) in both ambulatory and nonambulatory settings. 170 patients (1.1%) experienced the primary outcome of uLMA^TM failure, defined as an airway event requiring uLMA^TM removal and tracheal intubation. More than 60% of patients with uLMA^TM failure experienced significant hypoxia, hypercapnia, or airway obstruction; 42% were unable to be adequately ventilated due to significant leak.

Four risk factors contributing to LMA failure were identified:  surgical table rotation, male sex, poor dentition, thick neck, and increased body mass index. Patients in which the uLMA^TM failed were 3 times more difficult to mask ventilate. Among outpatients with uLMA^TM failure, 13.7% required unplanned admission to the hospital, of whom 5.6% required intensive care for persistent hypoxemia.

The results of this study support the use of the LMA as a safe supraglottic airway device with relatively low failure rate (1.1%). However, there are clear consequences to LMA failure, including unplanned or prolonged hospitalization. Furthermore, the researchers remind us that certain risk factors increase the rate of failure.