K Aoyama1, I Takenaka, T Sata, A Shigematsu. 1. Department of Anesthesiology, University of Occupational and Environmental Health, Japan, School of Medicine, Kitakyushu, Japan.
Abstract
PURPOSE: To assess the effect of cricoid pressure on the positioning of and ventilation through the laryngeal mask airway (LMA). METHODS: In a double-blind, randomized design, the LMA was inserted with (CP[+] group, n = 20) or without double-handed cricoid pressure (CP[-] group, n = 20). Ventilation through the LMA was assessed by measuring expiratory tidal volume and judged as adequate when a mean expiratory tidal volume of > or = 10 ml.kg-1 could be obtained. The LMA position was examined by fibreoscopy. The position of the mask relative to the cricoid cartilage and the cervical spine was radiologically examined (n = 10 in each group). RESULTS:Ventilation was adequate in all patients in the CP[-] group but in only five patients (25%) of the CP[+] group (P < 0.001). The glottis was visible fibreoptically below the mask aperture in all patients in the CP[-] group, but in only three patients in the CP[+] group (P < 0.001). Fibreoscopy showed that the mask was not inserted far enough in the remaining 17 patients of the CP[+] group. The reason for unsuccessful ventilation in the CP[+] group was excessive gas leakage (n = 2) and/or partial or complete airway obstruction (n = 13), which was noted fibreoptically. The radiographs showed that the tip of the mask in the CP[-] group was located below the level of the cricoid cartilage (C6 or C7 vertebra). The mask tip in the CP[+] group was above this level (C4 or C5 vertebra) (P < 0.01). CONCLUSION:Cricoid pressure impedes positioning of and ventilation through the LMA.
RCT Entities:
PURPOSE: To assess the effect of cricoid pressure on the positioning of and ventilation through the laryngeal mask airway (LMA). METHODS: In a double-blind, randomized design, the LMA was inserted with (CP[+] group, n = 20) or without double-handed cricoid pressure (CP[-] group, n = 20). Ventilation through the LMA was assessed by measuring expiratory tidal volume and judged as adequate when a mean expiratory tidal volume of > or = 10 ml.kg-1 could be obtained. The LMA position was examined by fibreoscopy. The position of the mask relative to the cricoid cartilage and the cervical spine was radiologically examined (n = 10 in each group). RESULTS: Ventilation was adequate in all patients in the CP[-] group but in only five patients (25%) of the CP[+] group (P < 0.001). The glottis was visible fibreoptically below the mask aperture in all patients in the CP[-] group, but in only three patients in the CP[+] group (P < 0.001). Fibreoscopy showed that the mask was not inserted far enough in the remaining 17 patients of the CP[+] group. The reason for unsuccessful ventilation in the CP[+] group was excessive gas leakage (n = 2) and/or partial or complete airway obstruction (n = 13), which was noted fibreoptically. The radiographs showed that the tip of the mask in the CP[-] group was located below the level of the cricoid cartilage (C6 or C7 vertebra). The mask tip in the CP[+] group was above this level (C4 or C5 vertebra) (P < 0.01). CONCLUSION: Cricoid pressure impedes positioning of and ventilation through the LMA.
Authors: Catherine M Algie; Robert K Mahar; Hannah B Tan; Greer Wilson; Patrick D Mahar; Jason Wasiak Journal: Cochrane Database Syst Rev Date: 2015-11-18
Authors: J Adam Law; Natasha Broemling; Richard M Cooper; Pierre Drolet; Laura V Duggan; Donald E Griesdale; Orlando R Hung; Philip M Jones; George Kovacs; Simon Massey; Ian R Morris; Timothy Mullen; Michael F Murphy; Roanne Preston; Viren N Naik; Jeanette Scott; Shean Stacey; Timothy P Turkstra; David T Wong Journal: Can J Anaesth Date: 2013-10-17 Impact factor: 5.063
Authors: C Frerk; V S Mitchell; A F McNarry; C Mendonca; R Bhagrath; A Patel; E P O'Sullivan; N M Woodall; I Ahmad Journal: Br J Anaesth Date: 2015-11-10 Impact factor: 9.166