David R R Lardner1, Robin G Cox, Alastair Ewen, Darren Dickinson. 1. Division of Pediatric Anesthesia, Alberta Children's Hospital at the University of Calgary, 2888 Shaganappi Trail N.W., Calgary, Alberta T3B 6A8, Canada. david.lardner@calgaryhealthregion.ca
Abstract
PURPOSE: To determine whether a functional difference exists between the size 2 laryngeal mask airway (LMA)-Classic (CLMA) and LMA-Proseal (PLMA) in anesthetized children who have received neuromuscular blockade. Airway leak during intermittent positive pressure ventilation (IPPV) and adequacy of fibreoptic laryngeal view were the primary study outcomes. METHODS: A randomized, controlled, single-blinded study of 51 ASA I or II children weighing 10-20 kg was undertaken. The anesthetic technique was standardized. Following insertion of the LMA and cuff inflation to 60 cm H(2)O, we measured oropharyngeal leak pressure and gastric insufflation and leak fraction during IPPV, and evaluated the adequacy of fibreoptic view. RESULTS:Oropharyngeal leak pressure measured by neck auscultation was higher for the PLMA compared to the CLMA (23.7 vs 16.5 cm H(2)O, P = 0.009) but, when measured by the inspiratory hold maneuver was not significantly different (24.8 vs 20.3 cm H(2)O, respectively, P = 0.217). Leak fraction values were similar for the CLMA and the PLMA (21.2%. vs 13.3%, respectively, P = 0.473). A satisfactory view of the larynx was obtained more frequently in the PLMA group (21/25 vs 10/25, P = 0.003). Gastric insufflation during leak determination was more common with the CLMA (12/26 vs 2/25 CLMA vs PLMA, respectively, P = 0.006). CONCLUSION: In children undergoing IPPV with neuromuscular blockade, the size 2 PLMA is associated with a higher leak pressure by auscultation and less gastric insufflation compared to the CLMA. Leak pressures assessed by manometric stability are similar with these two devices. The improved fibreoptic view of the larynx through the PLMA may be advantageous for bronchoscopy.
RCT Entities:
PURPOSE: To determine whether a functional difference exists between the size 2 laryngeal mask airway (LMA)-Classic (CLMA) and LMA-Proseal (PLMA) in anesthetized children who have received neuromuscular blockade. Airway leak during intermittent positive pressure ventilation (IPPV) and adequacy of fibreoptic laryngeal view were the primary study outcomes. METHODS: A randomized, controlled, single-blinded study of 51 ASA I or II children weighing 10-20 kg was undertaken. The anesthetic technique was standardized. Following insertion of the LMA and cuff inflation to 60 cm H(2)O, we measured oropharyngeal leak pressure and gastric insufflation and leak fraction during IPPV, and evaluated the adequacy of fibreoptic view. RESULTS: Oropharyngeal leak pressure measured by neck auscultation was higher for the PLMA compared to the CLMA (23.7 vs 16.5 cm H(2)O, P = 0.009) but, when measured by the inspiratory hold maneuver was not significantly different (24.8 vs 20.3 cm H(2)O, respectively, P = 0.217). Leak fraction values were similar for the CLMA and the PLMA (21.2%. vs 13.3%, respectively, P = 0.473). A satisfactory view of the larynx was obtained more frequently in the PLMA group (21/25 vs 10/25, P = 0.003). Gastric insufflation during leak determination was more common with the CLMA (12/26 vs 2/25 CLMA vs PLMA, respectively, P = 0.006). CONCLUSION: In children undergoing IPPV with neuromuscular blockade, the size 2 PLMA is associated with a higher leak pressure by auscultation and less gastric insufflation compared to the CLMA. Leak pressures assessed by manometric stability are similar with these two devices. The improved fibreoptic view of the larynx through the PLMA may be advantageous for bronchoscopy.