Abstract
We evaluated the ability of basic life support ambulance officers and anaesthetists to perform lung ventilation with a face mask. After induction of anaesthesia and institution of standardized airway conditions the ambulance officer or anaesthetist placed a mask on the patient’s face and lung ventilation was commenced. The order of hand grip (one vs two hands) was randomized. The mask was connected to a ventilator which had flow and pressure transducers in the inspiratory and expiratory breathing circuits. The output of these devices was sent to an electronic integrator to determine volumes. Calibration of the flow transducers was made against a spirometer while ventilating a test lung. Oesophageal insufflation was determined by listening over the epigastrium with a stethoscope. Data collected included presence of gastro-oesophageal insufflation, inspiratory and expiratory volumes. Expiratory volumes for ambulance officers and anaesthetists at 30 cm H2O were greater than that of ambulance officers at 20 cm H2O (P < 0.001) but profession of the mask holder or hand grip had no effect on expiratory volume. There was no difference in the mask leak when the professions were compared but ambulance officers had a lower mask leak with a two-handed grip at 20 cm H2O (P < 0.001). Anaesthetists had a greater incidence of gastro-oesophageal insufflation when a two-handed mask grip was utilized (P < 0.05). In healthy relaxed patients there appeared to be little difference between the ambulance officers and qualified anaesthetists in airway maintenance or mask-holding ability.
Résumé
Cette étude a pour objectif l’évaluation de l’habileté des ambulanciers et des anesthésistes à réaliser la ventilation pulmonaire avec une masque facial. Après l’induction de l’anesthésie, l’ambulancier ou l’anesthésiste place un masque sur le visage du patient et commence la ventilation. L’ordre de l’utilisation de la façon de tenir le masque (une ou deux mains) est randomisée. Le masque est branché à un ventilateur équipé de transducteurs de mesure de débit et de pression placés sur les branches inspiratoire et expiratoire du circuit. Le débit de ces dispositifs est transmis à un intégrateur qui détermine les volumes. Les transducteurs de débit sont calibrés par spirométrie sur un poumon artificiel. L’insufflation de l’oesophage est déterminée par auscultation de l’épigastre. Les données receuillies comprennent la présence d’insufflation gastro-oesophagienne et les volumes inspiratoires et expiratoires. Les volumes expiratoires engendrés par les anesthésistes et les ambulanciers à 30 cm H2O sont plus grands que ceux des ambulanciers à 20 cm H2O (P < 0.001) mais la profession de celui qui tient le masque n’a pas d’effet sur les volumes expiratoires. L’importance de la fuite n’est pas différente entre professions mais elle est moins importante pour les ambulanciers lorsqu’ils tiennent le masque à deux mains à 20 cm H2O (P < 0,001). Plus d’air pénètre dans l’estomac et l’oesophage quand les anesthésistes tiennent le masque à deux mains (P < 0,05). Chez des patients bien portants, il y a peu de différence entre l’habileté des ambulanciers et celles des anesthésistes qualifiés à maintenir l’intégrité des voies respiratoires et leurs façons de tenir le masque.
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This study was supported by a grant from the Ministry of Health of Ontario.
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Devitt, J.H., Brooks, D.A., Oakley, P.A. et al. Mask lung ventilation by ambulance personnel: a performance assessment. Can J Anaesth 41, 111–115 (1994). https://doi.org/10.1007/BF03009802
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DOI: https://doi.org/10.1007/BF03009802