Background and Goal of Study: We tested the hypothesis that the gender selection of ILMA size is efficient for ventilation and blind TI for patients with overweight and obese with predictive signs of difficult airway or after TI failure.
Materials and methods: The prospective study of 156 adults undergoing of the general anesthesia I-IV classes ASA (100 males and 56 females) with increased body mass index (BMI) 25-30 kg m-2 and obesity (BMI>30), in whom ILMA Fastrach™ was used electively or emergently at three clinical institutions from Oct 2007 to Oct 2015. Size selection was based on gender principle: ILM №5 for male and ILM №4 for female. Estimated parameters: ventilation by a facemask, success of insertion ILMA, quality of ventilation (ILMA-V) and time for insertion/removal of ILMA and ETT (ILMA-IT). 20/156 patients allocated randomly and regurgitation was assessed by pH strips before insertion and after removal of ILMA.
Results and discussion: 110 patients had predictive (4 or more) signs of difficult TI (PDTI); in 46 patients with unpredicted difficult TI and ILMA was inserted after 2 attempts intubation failure (UDTI). 93/156 (59.6%) had 5 or more signs of PDTI. 58/156 patients were morbidly obese with BMI>40 kg m-2; 13/58 - BMI>45, 10/58 - BMI>55. The ventilation by a facemask and ILMA was successfully inserted at the first attempt within 8.2±2.9 s after induction/ventilation in 100%.The blind TI through ILM (ETT № 7.5 or 8) was successful in 147/156 (94%) of cases, and in 91% at first attempt. Total TI time was 7.5±4.8 s with, on ILMA removal - 9.2±1.5 s. 5 blind attempts of TI through ILM wasn't possible; ILMA was removed and replaced by LMA Proseal or Supreme followed TI with direct laryngoscopy. 46/156 patients had only 2-3 DTI predictors, but TI with direct laryngoscopy was unsuccessful. In this patients TI through ILMA was made at the first attempt 40/46 (87%) patients; 6 patients (13%) required adjusting manoeuvre for successful ILMA-TI. In 1 case was situation “can´t intubate-can´t oxygenate”, ILMA provided ventilation/blind TI at the first attempt. Signs of regurgitation by pH (6.0) strips weren't registered.
Conclusion(s): The ILMA is an easy-to-use airway device with a high success rate of insertion and requires little training time for ILMA-V and ILMA-TI. The choice of ILMA size, based on the gender principle, has been efficient for ventilation and TI of obese patients with predictive signs of difficult airway or after intubation failure.

The method of gender selection mask size of the intubating laryngeal mask airway for overweight and obese patients