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Use of transcutaneous electrical stimulation in the control of postoperative pain
Use of Transcutaneous Electrical Stimulation in the Control of Postoperative Pain Results of a Prospective, Randomized, Controlled Study
Avram M. Cooperman, MD, Cleveland, Ohio Barbara Hall, RN, Cleveland, Ohio Katherine Mlkalacki, RN, Cleveland, Ohio Russel Hardy, MD, Cleveland, Ohio Edward Sadar, MD, ‘Cleveland, Ohio
Transcutaneous electrical stimulation has been effectively used to control acute and chronic conditions that produce pain [I-3]. Its use in the immediate postoperative period has been reported to be followed by a reduction in postoperative complications including atelectasis and ileus. A randomized prospective study was undertaken in consecutive patients undergoing abdominal operations to confirm these previous observations and to see whether the beneficial effects of the stimulator are due to psychological influences. Material and Methods Fifty consecutive patients about to undergo major intra-abdominal surgery were asked to participate in this study. When permission was granted, a brief explanation of the transcutaneous electrical stimulation and its use in the relief of postoperative pain was given. The relief of pain without negative side effects was stressed. All patients understood that comfort was the main objective and if the stimulator proved ineffective, medication was available for pain control. The stimulator used was the electronic pain controller (EPC Personal; Stim Tech, Minneapolis, MN). (Figure 1.) The patients were randomly assigned either to a stimulator with current or a stimulator without current (sham stimulator). The random assignment of stimulators was made by a nurse unfamiliar with the patients and not involved in their care. In the recovery room immediately after surgery, disposable foil electrodes, lubricated with jelly, were applied on either side of the incision. The electrodes were secured with tape and the stimulator controls were adjusted so that a subjective level of comfort was perceived From the Departments of Surgery and Newoswgery’. Cleveland Clinic Foundation. Cleveland, Ohio. Reprint requests shcuki a&Mssed be to Avram M. Coopemwn, MI, 9500 Euclid Avenue, Cleveland. Ohio 44106.
Volume 133, February 1977
by each patient. If incisional pain was unrelieved by the stimulator, diaxepam, 10 mg intramuscularly, was administered. If diazepam was ineffective in relieving the pain, meperidol, 75 to 100 mg intramuscularly, was administered and the stimulator disconnected. This procedure was repeated for five postoperative days each time the patient complained of pain. Preoperative and postoperative spirometry, arterial blood gas values, and chest roentgenograms were obtained in each patient. Temperature was recorded four times daily. All incisions were upper abdominal midline. Patient Population. Twenty-six female and twenty-four male patients comprised the study group. Ages ranged from 20 to 74 years. Eight women were in the control group and eighteen were assigned to stimulators. Fifteen of the twenty-four men were assigned control stimulators. Similar operations regarding type, magnitude, and length of surgery were performed in both groups and are listed in Table I.
F&we 7. The electronk electrodes.
paln controller and dtsposable
185
Cooperman et al
TABLE
I Operations Stimulator
Performed
in Control
0 NO Current El Currenf
and
Groups
80 Procedure Biliary operations Gastric Staging laparotomy Small bowel and colon resection Pancreatic resection Diagnostic laparotomy Ventral hernia
Control
Stimulators
9 7
8 7
4
4
2
3
0
3
1 1
1 0
P< 0.008 c
b B G s h
5 2 2
I6124
60
I l/26
4o
r
9 /26
6126
20
Results
Results were classified into one of three groups (Figure 2): (1) excellent results-patients were comfortable with the stimulator and required either no medicine or an occasional dose of diazepam; (2) good results-patients required diazepam or less than three doses of demerol per 24 hours; and (3) poor results-patients objected to a stimulator or required more than three doses of demerol per 24 hours. Of the patients who had the control stimulator (without current), 12 per cent had excellent results, 21 per centgood results,and 67 per cent poor results. Of the patients who had working stimulators, 35 per cent had excellent results, 42 per cent good results, and 23 per cent poor results. Thus, 77 per cent of patients with working stimulators had excellent or good results as contrasted with only 33 per cent of patients with control stimulators (p
The factors that influence the perception of pain are multiple and individual and include physical as well as psychological factors [2]. These factors are
186
0
1
EXCELLENT
GOOD
POOR
Patients who required no demerol or an occasional dose of Valium/ 24 hrs.
Patients who required valium plus a maximum of 3 doses of demerol/ 24 hrs.
Patients objected to stimulator or required more than 3 doses of demerol/ 24 hrs.
Flgure 2. Results of reilef of postoperative paln wiih sfhnulators Mow sfgnffkantm better resdts wfth the stlnwfator In all groups.
centrally modified by our previous experiences and ability to understand the cause of pain and grasp its consequences. Beecher’s study [4] of injured soldiers during World War II showed that soldiers who received significantwounds required narcotics for pain relief much less frequently than civilians who underwent major operations with similar incisions. Even the mere anticipation or mention of the word pain has been enough to increase the intensity of perceived pain [4]. Although few would deny that an abdominal incision is pain-producing, psychological factors are operative even in these patients. Melzack [5] has stated that a placebo given intramuscularly postoperatively provided pain relief in 35 per cent of patients whereas morphine will relieve pain in only 75 per cent of postoperative patients. A mechanism of pain perception has recently been described by Melzack and Wall [6], the “gate control” theory of pain. It is thought that pain is largely transmitted by small, unmyelinated “C” fibers, and that pain may be inhibited by the activity of large myelinated “A” fibers. Transcutaneous stimulation
The American Journal of Surgery
Transcutaneous
may thus act by stimulating large fiber afferents, which in turn suppress pain at cord level. That transcutaneous electrical stimulation can provide relief of pain has been shown by several reports. Shealy [2] used a stimulator to provide cutaneous relief and found excellent results in 80 per cent of patients in whom pain was confined to an area less than 6 cm square. Relief was less when larger areas were involved. Wall and Sweet [ 71 showed effective relief of chronic pain after transcutaneous stimulation for brief periods of time. Hymes et al [l] reported a large series of postoperative patients in whom transcutaneous electrical stimulation was used for the relief of acute pain. A reduction in the incidence of ileus and atelectasis and a greater relief of pain were reported. However, in this report, the control group, consisted of patients not using any stimulator and the possible psychological benefit of the apparatus could not be evaluated. In our study all patients received a stimulator that had the appearance of a working unit even though in half the cases no current was being conducted through the machine. Each patient, however, adjusted the frequency and amplitude of current to a comfortable level. It was reassuring to note, therefore, that patients who received stimulators with conducted current did significantly better than those of control patients. When factors of age, sex, type of disease (benign or malignant), preoperative use of narcotics, and length of operation were analyzed, only the type of disease and preoperative use of narcotics may have influenced the result. For both of these factors the numbers of patients were small. Of thirteen patients who underwent cholecystectomy (7 had control and 6 working stimulators), ten were classified as having excellent or good results, including four of seven control stimulator patients. In contrast, of eight patients who underwent staging laparotomy for Hodgkin’s disease and were anxious while awaiting the final pathology report, excellent results were noted in only two patients (both of whom had working stimulators) (p = 0.0272 by chi square analysis). All six patients who received narcotics for pain preoperatively received no pain relief from the stimulator. Another claim besides pain relief for transcutaneous electrical stimulation has been a reduction in respiratory complications and the prevention of ileus in the postoperative period [I]. This is difficult to evaluate and compare in different reports because definitions of terms differ and subjectivity may influence reporting. For example, the absence of bowel
Volume 133, February 1977
Electrical
Stimulation
for Pain
sounds may imply that ileus is present and the examiner has not auscultated for a sufficient length of time or a nasogastric tube has effectively prevented air from entering the small intestine. In our series, no differences between stimulator and control patients were seen regarding ileus, atelectasis, pneumonia, or length of stay in an intensive care unit. Respiratory complications were diagnosed by physical examination and by temperature elevation, arterial blood gases, spirometry, and roentgenographic changes. In our series there were no significant differences between control and stimulator patients.
Summary
Perception and relief of pain were studied in a varied group of fifty patients who had undergone laparotomy with upper abdominal midline incisions. Twenty-six patients were supplied with functioning transcutaneous electrical stimulators. Twenty-four received nonfunctioning machines. The controls were randomized by a nurse not otherwise involved in this study. Only seventeen of the total study group were judged failures and six of the patients had been receiving preoperative narcotics. Patient response was very favorable and pain relief was good to excellent, especially in one group with working stimulators (p
References 1. Hymes AC, Yonehiro EG, Raab OE, Nelson GD. Printy Al: Electrical stimulation for treatment and prevention of ileus and atelectasis. Surg Forum XXV: 222, 1974. 2. Shealy CN: Transcutaneous electroanalgesia. Surg forum XXIII: 419.1972. 3. Long DM: Electrical stimulation for relief of pain from chronic nerve injury. J Neurosurg 39: 718, 1973. 4. Seecher HK: Measurement of Subjective Responses. New York, Oxford University Press, 1959. 5. Melzack R: The perception of p&n. Scientific American 204: 41, 1961. 6. Melzack R, Wall PD: Pain mechanisms: a new theory. Science 150: 971, 1965. 7. Wall PD, Sweet WH: Temporary abolition of pain in man. Science 155: 108,1967.
187
Avram M. Cooperman, MD, Cleveland, Ohio Barbara Hall, RN, Cleveland, Ohio Katherine Mlkalacki, RN, Cleveland, Ohio Russel Hardy, MD, Cleveland, Ohio Edward Sadar, MD, ‘Cleveland, Ohio
Transcutaneous electrical stimulation has been effectively used to control acute and chronic conditions that produce pain [I-3]. Its use in the immediate postoperative period has been reported to be followed by a reduction in postoperative complications including atelectasis and ileus. A randomized prospective study was undertaken in consecutive patients undergoing abdominal operations to confirm these previous observations and to see whether the beneficial effects of the stimulator are due to psychological influences. Material and Methods Fifty consecutive patients about to undergo major intra-abdominal surgery were asked to participate in this study. When permission was granted, a brief explanation of the transcutaneous electrical stimulation and its use in the relief of postoperative pain was given. The relief of pain without negative side effects was stressed. All patients understood that comfort was the main objective and if the stimulator proved ineffective, medication was available for pain control. The stimulator used was the electronic pain controller (EPC Personal; Stim Tech, Minneapolis, MN). (Figure 1.) The patients were randomly assigned either to a stimulator with current or a stimulator without current (sham stimulator). The random assignment of stimulators was made by a nurse unfamiliar with the patients and not involved in their care. In the recovery room immediately after surgery, disposable foil electrodes, lubricated with jelly, were applied on either side of the incision. The electrodes were secured with tape and the stimulator controls were adjusted so that a subjective level of comfort was perceived From the Departments of Surgery and Newoswgery’. Cleveland Clinic Foundation. Cleveland, Ohio. Reprint requests shcuki a&Mssed be to Avram M. Coopemwn, MI, 9500 Euclid Avenue, Cleveland. Ohio 44106.
Volume 133, February 1977
by each patient. If incisional pain was unrelieved by the stimulator, diaxepam, 10 mg intramuscularly, was administered. If diazepam was ineffective in relieving the pain, meperidol, 75 to 100 mg intramuscularly, was administered and the stimulator disconnected. This procedure was repeated for five postoperative days each time the patient complained of pain. Preoperative and postoperative spirometry, arterial blood gas values, and chest roentgenograms were obtained in each patient. Temperature was recorded four times daily. All incisions were upper abdominal midline. Patient Population. Twenty-six female and twenty-four male patients comprised the study group. Ages ranged from 20 to 74 years. Eight women were in the control group and eighteen were assigned to stimulators. Fifteen of the twenty-four men were assigned control stimulators. Similar operations regarding type, magnitude, and length of surgery were performed in both groups and are listed in Table I.
F&we 7. The electronk electrodes.
paln controller and dtsposable
185
Cooperman et al
TABLE
I Operations Stimulator
Performed
in Control
0 NO Current El Currenf
and
Groups
80 Procedure Biliary operations Gastric Staging laparotomy Small bowel and colon resection Pancreatic resection Diagnostic laparotomy Ventral hernia
Control
Stimulators
9 7
8 7
4
4
2
3
0
3
1 1
1 0
P< 0.008 c
b B G s h
5 2 2
I6124
60
I l/26
4o
r
9 /26
6126
20
Results
Results were classified into one of three groups (Figure 2): (1) excellent results-patients were comfortable with the stimulator and required either no medicine or an occasional dose of diazepam; (2) good results-patients required diazepam or less than three doses of demerol per 24 hours; and (3) poor results-patients objected to a stimulator or required more than three doses of demerol per 24 hours. Of the patients who had the control stimulator (without current), 12 per cent had excellent results, 21 per centgood results,and 67 per cent poor results. Of the patients who had working stimulators, 35 per cent had excellent results, 42 per cent good results, and 23 per cent poor results. Thus, 77 per cent of patients with working stimulators had excellent or good results as contrasted with only 33 per cent of patients with control stimulators (p
The factors that influence the perception of pain are multiple and individual and include physical as well as psychological factors [2]. These factors are
186
0
1
EXCELLENT
GOOD
POOR
Patients who required no demerol or an occasional dose of Valium/ 24 hrs.
Patients who required valium plus a maximum of 3 doses of demerol/ 24 hrs.
Patients objected to stimulator or required more than 3 doses of demerol/ 24 hrs.
Flgure 2. Results of reilef of postoperative paln wiih sfhnulators Mow sfgnffkantm better resdts wfth the stlnwfator In all groups.
centrally modified by our previous experiences and ability to understand the cause of pain and grasp its consequences. Beecher’s study [4] of injured soldiers during World War II showed that soldiers who received significantwounds required narcotics for pain relief much less frequently than civilians who underwent major operations with similar incisions. Even the mere anticipation or mention of the word pain has been enough to increase the intensity of perceived pain [4]. Although few would deny that an abdominal incision is pain-producing, psychological factors are operative even in these patients. Melzack [5] has stated that a placebo given intramuscularly postoperatively provided pain relief in 35 per cent of patients whereas morphine will relieve pain in only 75 per cent of postoperative patients. A mechanism of pain perception has recently been described by Melzack and Wall [6], the “gate control” theory of pain. It is thought that pain is largely transmitted by small, unmyelinated “C” fibers, and that pain may be inhibited by the activity of large myelinated “A” fibers. Transcutaneous stimulation
The American Journal of Surgery
Transcutaneous
may thus act by stimulating large fiber afferents, which in turn suppress pain at cord level. That transcutaneous electrical stimulation can provide relief of pain has been shown by several reports. Shealy [2] used a stimulator to provide cutaneous relief and found excellent results in 80 per cent of patients in whom pain was confined to an area less than 6 cm square. Relief was less when larger areas were involved. Wall and Sweet [ 71 showed effective relief of chronic pain after transcutaneous stimulation for brief periods of time. Hymes et al [l] reported a large series of postoperative patients in whom transcutaneous electrical stimulation was used for the relief of acute pain. A reduction in the incidence of ileus and atelectasis and a greater relief of pain were reported. However, in this report, the control group, consisted of patients not using any stimulator and the possible psychological benefit of the apparatus could not be evaluated. In our study all patients received a stimulator that had the appearance of a working unit even though in half the cases no current was being conducted through the machine. Each patient, however, adjusted the frequency and amplitude of current to a comfortable level. It was reassuring to note, therefore, that patients who received stimulators with conducted current did significantly better than those of control patients. When factors of age, sex, type of disease (benign or malignant), preoperative use of narcotics, and length of operation were analyzed, only the type of disease and preoperative use of narcotics may have influenced the result. For both of these factors the numbers of patients were small. Of thirteen patients who underwent cholecystectomy (7 had control and 6 working stimulators), ten were classified as having excellent or good results, including four of seven control stimulator patients. In contrast, of eight patients who underwent staging laparotomy for Hodgkin’s disease and were anxious while awaiting the final pathology report, excellent results were noted in only two patients (both of whom had working stimulators) (p = 0.0272 by chi square analysis). All six patients who received narcotics for pain preoperatively received no pain relief from the stimulator. Another claim besides pain relief for transcutaneous electrical stimulation has been a reduction in respiratory complications and the prevention of ileus in the postoperative period [I]. This is difficult to evaluate and compare in different reports because definitions of terms differ and subjectivity may influence reporting. For example, the absence of bowel
Volume 133, February 1977
Electrical
Stimulation
for Pain
sounds may imply that ileus is present and the examiner has not auscultated for a sufficient length of time or a nasogastric tube has effectively prevented air from entering the small intestine. In our series, no differences between stimulator and control patients were seen regarding ileus, atelectasis, pneumonia, or length of stay in an intensive care unit. Respiratory complications were diagnosed by physical examination and by temperature elevation, arterial blood gases, spirometry, and roentgenographic changes. In our series there were no significant differences between control and stimulator patients.
Summary
Perception and relief of pain were studied in a varied group of fifty patients who had undergone laparotomy with upper abdominal midline incisions. Twenty-six patients were supplied with functioning transcutaneous electrical stimulators. Twenty-four received nonfunctioning machines. The controls were randomized by a nurse not otherwise involved in this study. Only seventeen of the total study group were judged failures and six of the patients had been receiving preoperative narcotics. Patient response was very favorable and pain relief was good to excellent, especially in one group with working stimulators (p
References 1. Hymes AC, Yonehiro EG, Raab OE, Nelson GD. Printy Al: Electrical stimulation for treatment and prevention of ileus and atelectasis. Surg Forum XXV: 222, 1974. 2. Shealy CN: Transcutaneous electroanalgesia. Surg forum XXIII: 419.1972. 3. Long DM: Electrical stimulation for relief of pain from chronic nerve injury. J Neurosurg 39: 718, 1973. 4. Seecher HK: Measurement of Subjective Responses. New York, Oxford University Press, 1959. 5. Melzack R: The perception of p&n. Scientific American 204: 41, 1961. 6. Melzack R, Wall PD: Pain mechanisms: a new theory. Science 150: 971, 1965. 7. Wall PD, Sweet WH: Temporary abolition of pain in man. Science 155: 108,1967.
187