title: Comparison of effectiveness of two commonly used two-handed mask ventilation techniques on unconscious apnoeic obese adults.
abstract: Mask ventilation and tracheal intubation are basic techniques for airway management and mutually inclusive rescue measures to restore ventilation. The aim of this study was to compare the effectiveness of mask ventilation between two commonly used techniques of two-handed mask ventilation in obese unconscious apnoeic adults.
  Eighty-one obese adults received mask ventilation after induction using C-E clamp and modified V-E clamp techniques in a randomized crossover manner. Mechanical ventilation was provided using a pressure-control mode, at a rate of 10 bpm, with an inspiratory-to-expiratory time ratio of 1:2 and a pre-set plateau airway pressure of 20 cm H 2 O. The primary outcome was expired tidal volume.
  The BMI for the subjects was 37 ( sd 4.9) kg m -2 . The failure rates for mask ventilation (tidal volume≤anatomical dead space) were 44% for the C-E technique and 0% for the V-E technique ( P <0.001). Tidal volume was significantly lower for the C-E than the V-E technique [371 ( sd 345) vs 720 (244) ml, P <0.001]. The peak airway pressures were 21 ( sd 1.5) cm H 2 O for the C-E technique and 21 (1.3) cm H 2 O for the V-E technique.
  Mask ventilation using the modified V-E technique is more effective than with the C-E technique in unconscious obese apnoeic adults. Subjects who fail ventilation with the C-E technique can be ventilated effectively with the V-E technique.
  NCT02580526.
authors.affiliation: Department of Anaesthesia, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.|Department of Anaesthesiology.
authors.forename: M
authors.initials: M
authors.lastname: Fei
authors.affiliation: Department of Anaesthesiology.
authors.forename: J L
authors.initials: JL
authors.lastname: Blair
authors.affiliation: Department of Anaesthesiology.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rice
authors.affiliation: Department of Anaesthesiology.
authors.forename: D A
authors.initials: DA
authors.lastname: Edwards
authors.affiliation: Department of Anaesthesiology.
authors.forename: Y
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Department of Anaesthesiology.
authors.forename: M A
authors.initials: MA
authors.lastname: Pilla
authors.affiliation: Department of Biostatistics, Vanderbilt University Medical Center, 1301 Medical Center Drive, 4648 TVC, Nashville, TN 37232-5614, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Shotwell
authors.affiliation: Department of Anaesthesiology.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058109:Airway Management / Q000379:methods*; D000402:Airway Obstruction / Q000150:complications; D001049:Apnea / Q000150:complications*; D015992:Body Mass Index; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D017214:Laryngeal Masks; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D012121:Respiration, Artificial / Q000379:methods*; D012126:Respiratory Dead Space; D013990:Tidal Volume; D014474:Unconsciousness; D055815:Young Adult
keywords: airway obstruction; difficult airway; mask ventilation; obesity; pressure-controlled ventilation