Effects of a 1-minute back rub on mixed venous oxygen saturation and heart rate in critically ill patients.

Abstract

In this study we evaluated mixed venous oxygen saturation (SvO2) and heart rate responses after a 1-minute back rub in 173 critically ill patients. The back rub was the third and last intervention in a study conducted in intensive care units at four hospitals. For this multiple-intervention study all patients were placed in a supine position to obtain baseline SvO2 and heart rate, then underwent suctioning via endotracheal tube, and were turned to a lateral position. After 15 minutes in a side-lying position, the subjects received a 1-minute back rub. Data were collected immediately after the back rub and at 1-minute intervals for 4 minutes. After the back rub, SvO2 decreased immediately from the mean baseline of 67% to 63% and gradually increased, returning to baseline by minute 4. The mean baseline heart rate of 99 beats/min increased to 103 beats/min immediately after the back rub and gradually decreased after massage, but remained higher than baseline by minute 4. Although the findings were statistically significant (p = 0.0001), these minimal physiologic changes do not represent clinical significance. Based on the findings, the back rub, a traditional nursing measure that can provide comforting touch, represented a minor stimulus affecting heart rate and oxygen demands in most critically ill patients. However, because of the variability found in heart rate and SvO2, individual responses need to be assessed.