Effect of operation table height on ease of mask ventilation, laryngeal view, and endotracheal intubation success

Abstract

Background and Aims: Optimal patient positioning and operating table height are essential for an ergonomic posture of an anesthesiologist in which there is minimal or no strain on thewrist during mask ventilation. It also avoids flexion of the neck, lower back, and knee bending at the time of laryngoscopy and intubation. Material and Methods: One hundred eighty patients were randomly allocated to three groups based on different table heights. The height of the table is kept at the mid-sternum level of an anesthesiologist in group 1, at the xiphoid process in group 2, and at the level of umbilicus in group 3. Laryngoscopic view with or without postural changes (exertion at wrist joint, flexion of the neck, lower back, or knee bending) was graded as per Cormack Lehane’s (CL) grading. The degree of discomfort experienced by the anesthesiologist during mask ventilation or tracheal intubation was graded subjectively (1 = no discomfort, 2 = mild discomfort, 3 = moderate discomfort, and 4 = severe discomfort) at different table heights. Postural changes required to obtain the best glottic view and quality of endotracheal (ET) intubation (intubation time and attempts required) were also noted. For analysis, quantitative variables were expressed as mean ± SD and compared using unpaired t or analysis of variance test. Qualitative variables were expressed as frequencies/percentages and compared using the Chi-square test. Results with P value <0.05 were considered significant statistically. Results: Moderate discomfort (strain at wrist joint) during bag–mask ventilation was experienced by the anesthesiologist in a maximum number of patients in group 1 (81.7%). Significant improvement was seen in CL grade after the use of postural modifications in groups 1 and 2 (P value ≤0.05). Greater postural modifications were required during ET intubation at lower table heights (group 3). Conclusions: It is advisable to adopt higher table positioning in relation to anesthesiologist performing the laryngoscopy for smooth and single-attempt ET intubation since the best laryngoscopic view and intubation with minimal postural modifications was seen at higher table heights (at the mid-sternum level of an anesthesiologist).

Keywords

• bag–mask ventilation difficulty
• direct laryngoscopy
• laryngoscopic view
• posture
• table height