Comparison of Ventilation Quality during Induction of General Anesthesia through Nasal and Face Mask Methods in Patients with Body Mass Index of Greater than 25

Abstract

Background: Face mask ventilation has a distinct place in anesthesiology. One of the difficulties (obstacles, problems) with a mask, is laryngeal airway obstruction caused by the backward displacement of the tongue and soft tissue which is further exacerbated by obesity (body mass index over 25). Considering the fact that ventilation using a nasal mask appears to cause fewer problems especially in obese patients, we decided to compare the quality of ventilation after the induction of general anesthesia using ventilation through an anatomical face mask and anatomical nasal mask in patients with a body mass index (BMI) over 25 in this study.
Methods: The study was a clinical trial, conducted on 70 patients between the ages of 18 and 70 years, with a BMI over 25, who were candidates for elective orthopedic surgery under general anesthesia at the Alzahra Hospital operating room. After evaluation of the inclusion criteria, the subjects were selected. Once placed on the operating table, the patients were administered 100% oxygen using a face mask held at proximity to the face for 3 minutes, after which anesthesia induction medication were administered to all patients. Subsequently, the patients were randomly divided into 2 groups. In the first group, ventilation was undertaken using the standard mask ventilation with 100 % oxygen for 3 minutes. In the second group, ventilation was performed through an anatomical nasal mask. The mean expiratory volume, mean SpO2, mean end tidal CO2 (Et CO2) and mean airway pressure were measured, recorded and compared in both groups.
Results: From the ventilation parameters, maximum airway pressure during the 2nd minute after initiation of mask ventilation was significantly higher in the face mask group compared to the nasal mask group (4.6 +/- 1.6 and 12.5 +/- 1.7 respectively, p< 0.001) and the SpO2 at this time was higher in the nasal mask group compared to the face mask group (97.6 +/- 1.7 and 95.3 +/- 3 respectively, p< 0.001). Other parameters related to ventilation did not show any significant difference.
Conclusion: According to the findings in this study, it can be concluded that ventilation with a nasal mask is more efficient than a face mask in patients with a BMI> 25 and is followed by a reduced amount of risk and complications.