Learning Track:	11. Respiration and Airway Management
Title:	Intubating laryngeal mask airway for overweight and obese patients: gastro-oesophageal reflux during positive pressure ventilation
Author(s):	Stamov V.I.1, Dolbneva E.L.2, Gavrilov S.V.3, Bunyatyan A.A.2
Institute(s):	1Sechenov First Moscow State Medical University, Dept of Anaesthesiology & Intensive Care, Moscow, Russian Federation, 2Petrovsky National Research Centre for Surgery, Dept of Anaesthesiology & Intensive Care, Moscow, Russian Federation, 315th City Clinical Hospital, Dept of Anaesthesiology & Intensive Care, Moscow, Russian Federation
Text:	Background and Goal of Study: There are concerns that the use of the intubating laryngeal mask airway ILMA (ILMA Fastrach™) for patients with obesity might promote gastro-oesophageal reflux and subsequent regurgitation of gastric contents especially during intermittent positive pressure ventilation (IPPV). We tested the hypothesis that whether or not the use IPPV via ILMA is associated with a higher risk of gastro-oesophageal reflux for patients with overweight and obesity.
Materials and Methods: In order to asses if the use ILMA is associated with an increased risk of gastric regurgitation during mechanical ventilation (V), we studied 40 patients allocated randomly out of 156 adults undergoing of the general anesthesia I-IV classes ASA (20/100 males and 20/56 females) with increased body mass index (BMI) and obesity (BMI >30 kg•m-2), in whom ILMA was used electively within 25 minutes after induction and IPPV. Size selection ILMA was based on gender principle (5 for male, 4 for female). Estimated parameters: amounts of predictors difficult TI, V by a facemask; success of insertion ILMA, quality of IPPV (ILMA-V) and time for insertion/removal of ILMA and ETT (ILMA-IT). Regurgitation risk was assessed by ph strips before insertion (strip-1) and after blind tracheal intubation (TI) and removal of ILMA (strip-2). Induction: midazolam 0,1-0,15 mg•kg-1, propofol 2-3 mg•kg-1, fentanyl 1-1,5 mkg•kg-1, rocuronium 0.6 mg kg-1. We used descriptive statistics and Wilcoxon test.
Results and Discussion: 38 patients had predictive (4 or more) signs of difficult TI (see Table). In 2 patients (BMI 30-35 kg•m-2) with unpredicted difficult TI and ILMA was inserted after 2 attempts TI failure.The V by a facemask was successfully and ILMA inserted at the first attempt within 8.2±2.9 s after induction in 100% and after them ILMA was connected to the anesthetics machine and IPPV was beginning 25 min to normocapnia. Subsequent blind TI through ILM (ETT № 7.5 or 8) was successful in 40/40 (100%) of cases, and in 95% at first attempt. Signs of regurgitation weren't registered (as indicated by a decrease in pH strips to below 4). Both pH strips have a pH about 6.0 (р=0.11). 
BMI, kg•m-2	25-30 N=2 (5%)	30-35 N=20 (50%)	35-40 N=12 (30%)	40-45 N=4 (10%)	>45 N=2 (5%)
Number of predictors per patients	4	3,7	4,7	4,5	4
[Table 1]


Conclusion(s): In our study we found no evidence to suggest that the use of IPPV via ILMA increases the risk of gastro-oesophageal reflux for patients with overweight and obesity.
Ethical Research Declaration:	4. Prospective case series involving a new procedure or treatment
Preferred Presentation Type:	Clinical or experimental study