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

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.