Short-duration transcutaneous electrical nerve stimulation in the postoperative period of cardiac surgery.
BACKGROUND
Respiratory muscle strength has been related to the postoperative outcome of cardiac surgeries. The main documented therapeutic purpose of transcutaneous electrical nerve stimulation (TENS) is the reduction of pain, which could bring secondary benefits to the respiratory muscles and, consequently, to lung capacities and volumes.


OBJECTIVE
The objective of the present study was to evaluate the effectiveness of short-duration transcutaneous electrical nerve stimulation (TENS) in the reduction of pain and its possible influence on respiratory muscle strength and lung capacity and volumes of patients in the postoperative period of cardiac surgery.


METHODS
Twenty five patients with mean age of 59.9 +/- 10.3 years, of whom 72% were men, and homogeneous as regards weight and height, were randomly assigned to two groups. One group received therapeutic TENS (n = 13) and the other, placebo TENS (n = 12), for four hours on the third postoperative day of cardiac surgery. Pain was analyzed by means of a visual analogue scale, and of respiratory muscle strength as measured by maximum respiratory pressures and lung capacity and volumes before and after application of TENS.


RESULTS
Short-duration TENS significantly reduced pain of patients in the postoperative period (p < 0.001). Respiratory muscle strength (p < 0.001), tidal volume (p < 0.001) and vital capacity (p < 0.05) significantly improved after therapeutic TENS, unlike in the placebo group.


CONCLUSIONS
Short-duration TENS proved effective for the reduction of pain and improvement of respiratory muscle strength, as well as of lung volumes and capacity.
Gregorini
Cristie
C
Universidade Federal de São Paulo, São Paulo, SP, Brasil.
Cipriano Junior
Gerson
G
Aquino
Leticia Moraes de
LM
Branco
João Nelson Rodrigues
JN
Bernardelli
Graziella França
GF
D000368:Aged; D006348:Cardiac Surgical Procedures; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D010147:Pain Measurement; D010149:Postoperative Pain / Q000628:therapy*; D011184:Postoperative Period; D012132:Respiratory Muscles / Q000502:physiology*; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D013997:Time Factors; D014109:Total Lung Capacity / Q000502:physiology; D004561:Transcutaneous Electric Nerve Stimulation; D016896:Treatment Outcome