Gastric distension and airway management during laparoscopic cholecystectomy comparing Ambu Aura Once LMA and endotracheal tube: a randomised study

V. Cengic, M.Juros-Zovko, I.Keser, D.Imamovic, L.Aganovic, L.Muminagic

	
Background and Goal of Study 
The use of the laryngeal mask airway (LMA) for laparoscopic cholecystectomy is still  indication with controversial data and study's results. 
The goal of this randomized study is to compare Ambu Aura Once LMA and endotracheal tube with respect to intensity of gastric insufflation and distension in such indication.

Material and Methods
This was a prospective, single blinded study with 90 adult patients ASA I-II, scheduled for elective laparoscopic cholecystectomy, randomly allocated into two groups: ETT and Ambu Aura Once LMA group. Non fasted patients for 6 h, with BMI >30 kg/m2 and with hiatus hernia or gastrooesophageal reflux were excluded. Following induction of anesthesia, airway devices were placed by a single experienced anaesthesiologist, without bag and mask ventilation before placing. Anaesthesia was maintained with sevoflurane in N2O and oxygen (FiO2 0,3-0,4) with positive pressure ventilation. In LMA group just seal intracuff pressure was used, with tidal volume of 6-7ml/kg. Standard non-invasive monitoring was applied. The surgeon, blinded to the type of airway, scored stomach size (0-10) at insertion and before of laparoscope removal. Any complications were recorded. 

Results and Discussion
Device placement was successful in all patients and adequate ventilation was achieved  in both groups. Incidence and degree of change in gastric distension were similar in both groups (p=0.392), without disturbing surgical view. Mean oropharyngeal leak pressure in the LMA group was 22 cm H2O and airway presure was similar in both groupe, up to 20 cm H2O (p=0.811). There were not statistically significant differences between two groups for SpO2 and EtCO2. No specific complications were noted. Ambu Aura Once LMA with serious selection of patients, in the hands of experienced  anesthesiologist is an appropriate airway device in a such indication, confirmed in many previous works, even though consensus has not been reached yet.  

Conclusion
A correctly placed and maintained by experienced anaesthesiologist, Ambu Aura Once LMA provides an efficient airway for positive pressure ventilation during laparoscopic cholecystectomy. Gastric distension occurs with equal frequency and intensity with either airway devices.   

References:
Maltby JR, Beriault MT, Watson NC, Fick GH. Gastric distension and ventilation during laparoscopic cholecystectomy: LMA-classic vs. tracheal intubation. Canadian Journal of Anaesthesia. 2000;47:622–6. 
NAP4 – National Audit Project (UK) 2010. Major complications of airway management in the United Kingdom Report and findings March 2011. Editors Cook T, Woodall N. and Frerk C.


06 / Gastric distension and airway management during laparoscopic cholecystectomy comparing Ambu Aura Once LMA and endotracheal tube: a randomised study