Efficiency of face mask ventilation before and after neuromuscular blockade: A randomised, double-blind controlled study

Abstract

Background and Aims: The traditional practice of administrating neuromuscular blocking drugs (NMBDs) after checking face mask ventilation is challenged repeatedly. This study compared the efficiency of face mask ventilation before and after administrating an NMBD in a patient with a normal airway. The secondary outcome measured was the grade of mask ventilation and tracheal intubating conditions. Methods: After ethical approval, patients (n = 120) in the age group of 18–65 years scheduled for elective surgery under general anaesthesia were randomly assigned into two groups. Group 1 received an NMBD before checking face mask ventilation. Group 2 received an NMBD after checking face mask ventilation. Lungs were ventilated for 180 s, during which expiratory tidal volume (Vte) was recorded as the primary outcome. Hans’s grading for face mask ventilation was used to grade mask ventilation. The ease of intubation was assessed based on intubating conditions (ease of laryngoscopy, vocal cord movement, and limb movement). SPSS 20.0 software was used for statistical analysis. Results: For a total of 180 seconds of mask ventilation, the mean (standard deviation) Vte measured after apnoea was significantly higher in Group 1 versus Group 2 [471.9 (63.3) vs 434.8 (77.0) mL/breath, P = 0.004]. The intubating condition was either excellent or good in all patients. Conclusion: The administration of NMBDs resulted in a larger mask Vte and shorter intubation time.