Effect of the Height of the Operating table on Ergonomics during Spinal anesthesia

Abstract

Introduction The height of the operating table is related to the performance of the procedure and the discomfort of the operator. The aim of this study was to investigate the influence of different operating table heights on the accuracy of needle insertion and the discomfort of the anesthetist during spinal anesthesia.

Methods Sixty patients were randomly allocated into 4 groups by the landmarks on the anesthetists body: umbilicus (U), lowest rib margin (L), xiphoid process (X), and nipple (N). Before induction of anesthesia, the height of the operating table was adjusted to each group. All patients were in the lateral decubitus position with their shoulders and hips perpendicular to the table. Spinal anesthesia was performed by median approach. The primary outcome was the initial angle between the patients skin and the spinal needle in view of coronal plane. Until the success of the spinal anesthesia, each coronal angle was measured in company with the sagittal angle. The anesthetists posture was recorded by taking pictures and the degree of flexion of the neck, back, and knee was measured. At the end of the procedure, the overall subjective discomfort of the anesthetist was investigated.

Results Fifteen patients per each group, exclusive of 1 case which converted to general anesthesia, were analyzed. The initial coronal angle between the patients skin and the spinal needle was the most perpendicular in group X (90.8°) and the most remote from 90° in the group U (98.1°). The sagittal angles and the success rate were not different between the groups. The subjective necessity for bending the joints was the highest in group U. The objective degree of neck, back, and knee flexion was the highest in group U and the lowest in group X and group N. Anesthetists complained of discomfort in group U and L compared to group X and N (5.8 and 5.1 vs 2.1 and 2.3).

Conclusions At the xiphoid and nipple level, the angle between the patients skin and the spinal needle was optimal, and both objective and subjective discomforts of the anesthetists were minimal.