Effects of spinal immobilization at 20° on end-tidal carbon dioxide.

ABSTRACT

OBJECTIVE: The aim was to determine the effect on end-tidal carbon dioxide (ETCO2) of spinal immobilization (SI) at a conventional 0° angle and to investigate the usefulness of immobilization at a 20° angle for preventing possible hypoventilation. METHODS: The study included 80 healthy volunteers, randomly divided into two groups. Spinal backboards and cervical collars were applied in Group 1 using a 0° angle and in Group 2 using a 20° angle, with the head up. SI was continued for 1 h, and ETCO2 values were measured at the 0th, 30th and 60th minute. RESULTS: There were no significant differences between the groups in 0th and 30th minute ETCO2. However, after 60th minute, results showed a statistically significant increase in ETCO2 in Group 1 (35.5 mmHg [IQR 25-7535-38]) compared to Group 2 (34 mmHg [IQR 25-7533-36]) (p < 0.001). During SI, there was a statistically significant increase in ETCO2 in Group 1 (35 mmHg [IQR 25-7534-36], 35.5 mmHg [IQR 25-7534-37] and 36 mmHg [IQR 25-7535-38] respectively at the 0th, 30th and 60th minute after SI) (p < 0.001) and no change in Group 2. Also, we found statistically significant differences between ΔETCO2 levels in Groups 1 and 2 at all 3 time intervals. CONCLUSION: Conventional SI with an angle of 0° led to an increase in ETCO2 while subjects immobilization at a 20° angle maintained their initial ETCO2 values. Immobilization at 20° may prevent decompensation in patients who have thoracic trauma or lung diseases or those who are elderly, pregnant, or obese.