Abstract
BACKGROUND: The primary objective of this study was to compare the effect of ventilation using the ProSeal™ laryngeal mask airway (PLMA) with facemask and oropharyngeal airway (FM), prior to laryngoscopy, on arterial oxygenation in morbidly obese patients undergoing bariatric surgery. METHODS: Forty morbidly obese patients were randomly recruited to either PLMA or FM. After pre-oxygenation (FiO2 1.0) in the ramp position with continuous positive airway pressure of 10 cm H2O for 5 min, anaesthesia was induced. Following loss of jaw thrust oropharyngeal airway, the FM and PLMA were inserted. On achieving paralysis, volume control ventilation with PEEP (5 cm H2O) was initiated. The difficulty in mask ventilation (DMV) in FM, number of attempts at PLMA and laryngoscopy were graded (Cormack and Lehane) in all patients. Time from onset of laryngoscopy to endotracheal tube confirmation was recorded. Hypoxia was defined as mild (SpO2 ≤95%), moderate (SpO2 ≤90%) and severe (SpO2 ≤85%). RESULTS: Significant rise in pO2 was observed within both groups (P=0.001), and this was significantly higher in the PLMA (P=0.0001) when compared between the groups. SpO2 ≥ 90% (P=0.018) was seen in 19/20 (95%) patients in PLMA and 13/20 (65%) in FM at confirmation of tracheal tube. A strong association was found between DMV and Cormack Lehane in the FM group and with number of attempts in the PLMA group. No adverse events were observed. CONCLUSION: ProSeal™ laryngeal mask airway as conduit prior to laryngoscopy in morbidly obese patients seems effective in increasing oxygen reserves, and can be suggested as a routine airway management technique when managing the airway in the morbidly obese.