Effects of spinal immobilization at 20° on respiratory functions

The purpose of the study is to investigate whether spinal immobilization with a long backboard (LBB) and semirigid cervical collar (CC) at 20° instead of 0° conserve pulmonary functions, including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio.

The study included 56 adult healthy volunteers. Volunteers were randomly divided into 2 groups, and those in the first group (group 1) had LBBs and CCs applied at 0° (n=30), whereas volunteers in the second group (group 2) had LBBs and CCs applied at 20° (n=26). All volunteers were given pulmonary function tests, which included FEV1 and FVC levels and FEV1/FVC ratios, while in the sitting position. Measurements were repeated at 0, 5, and 30 minutes.

Results showed significant decreases in FEV1 and FVC values and FEV1/FVC ratios in group 1 and significant decreases in FEV1 values and FEV1/FVC ratios in group 2 (P<.001). However, FVC values were not decreased in group 2 when compared to basal levels taken while in a sitting position (P=.45). In addition, the study evaluated the amounts of decrease in the FEV1 and FVC levels and the FEV1/FVC ratios (ΔFEV1, ΔFVC, and ΔFEV1/FVC ratio). Results showed that ΔFEV1 values compared to basal levels and levels at 0, 5, and 30 minutes were all lower in group 2 than in group 1. However, ΔFEV1/FVC ratios were similar in both groups.

The results of this and previous studies have shown that traditional spinal immobilization decreases respiratory function, whereas using spinal immobilization at 20° can reduce this decrease in function.