The Efficacy and Safety of Intrathecal Morphine for Postoperative Pain Management in Srinagarind Hospital

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1 The Efficacy and Safety of Intrathecal Morphine for Postoperative Pain Management in Srinagarind Hospital Panaratana Ratanasuwan Yimyaem M.D.,* Duenpen Horatanaruang M.D.,* Kanchana Uppan M.D.,* Wimonrat Krisanaprakornkit M.D.,* Somboon Thienthong M.D., * Suthannee Simajareuk M.D.* àõ : ª æ «ª Õ Õß Õ åøïπ ß àõß πà ß æ ËÕ ß ª«À ßºà µ π ßæ» π π å æπ µπå µπ ÿ«è â æ..,* Õπ æá ÀàÕ µπ Õß æ..,* π Õÿªªí æ..,* «µπå ƒ ª æ..,* Ÿ å π Õß æ..,* ÿ ππ æ..* * «««ßæ» π π å æ» µ å À «Õπ àπ À Àµÿº ß ª««À â Ÿà ª à«π ß â Õ «à ª - æ Ë π «ÿ «ª«π À ßºà µ à«â ß ª«ÿà opioids πºÿâªé«â â Õ åøïπ â ß àõß Àπ Õ ËÕÀÿâ πà ß ß àõß πà ß ªìπ«ÕßÀ ß à «À π È ß Àπà«ß ª«ßæ» π π å ß âπ â æ ËÕ ß ª«À ßºà µ «µ ÿª ß å æ ËÕ» ª æ ß ª«Õÿ µ å «âõπ «æ ßæÕ ÕߺŸâªÉ«Ë â ß ª««Õ åøïπ â àõß πà ß æ ËÕ ß ª«À ßºà µ Ë ßæ» π π å âõ Ÿ âõπà ß π ß ª«ÕßÀπà«ß ª«(Acute Pain Service ; APS) «6 Õπµ Èß µà Õπ ß ÿπ π 2547 ÕߺŸâªÉ«ÿ Ë â ß ª««Õ åøïπ â àõß πà ß æ ËÕ ß ª«À ßºà µ âõ Ÿ Ë» â à Õ ÿ æ» µ Àπàß Ë ºà µ «Ë â ÿ æ Õß ß ª«Ëߪ π µ «ºŸâªÉ«Õß â ª 𠫪«Numeric Rating Scale (NRS) À Õ Verbal Rating Scale (VRS) π Õß Õ åøïπ Ë â «âõπ Ë Èπ π«π À ßºà µ «æ ßæÕ ÕߺŸâªÉ«µàÕ ß ª«Ë â º» âõ Ÿ π ºŸâªÉ«π«π 274 à«π À à ªìπ ºà µ àõß âõß à«π à ß àπ ºà µ Õ ßÀπâ âõß ªìπ âõ 57 π Õ åøïπ Ë â àõß πà ß Ë π â Ë ÿ Õ 0.2. ªìπ âõ 81 «ª«æ π«π À ßºà µ æ «à ºŸâªÉ««ª«Á πâõ ª π ß ªìπ âõ 77, µ π πõß «π ËÕπ À«/ Õ ºŸâªÉ««ª«Á πâõ ª π ß ªìπ âõ *Department of Anesthesiology, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University 102

2 37, µ ºŸâªÉ«âÕ 43 «ª«Ë Ÿß Ë ÿ π 24 Ë«ß À ßºà µ Õ ª«ÿπ ß º â ß ß Ëæ àõ Ë ÿ ÕÕ π Ëπ âõ π π à«π Ë à π Õ âõ 23 à«π À à Õ æ ß Á πâõ âßà à À À Õ «âõπ Ë ÿπ ß Èπ ºŸâªÉ«à«π À à âõ 73 «æ ßæÕ µàõ«ß ª«Ë â ÿª ß ª«Õ åøïπ â ß àõß πà ß æ ËÕ ß ª«À ßºà µ π ßæ» π π å àæ «âõπ ÿπ ß Ê ºŸâªÉ«à«π À à «æ ßæÕ µàõ ß ª««π È Thai J Anesthesiology 2007 ; 33(2) : Introduction In 1979, Behar et al. 1 and Wang et al. 2 reported the first human use of epidural and intrathecal opioids to manage acute postoperative pain. Neuraxial analgesia has proven to be an effective means of achieving postoperative pain control, with minimal exposure to opioids in patients. Morphine, an opioid analgesic approved by the Food and Drug Administration for intrathecal (IT) use, has been used both epidurally and intrathecally for this pur-pose. When administered intrathecally, morphine may achieve a longer duration of analgesia than epidural administration. 3 Both routes, however, are associated with frequent incidence of side-effects, including itching and postoperative nausea-the most common causes of dissatisfaction with postoperative analgesia, 4 Notwithstanding, we use intrathecal opioids for postoperative analgesia at our hospital. This retrospective study summarizes our experience with respect to the quality of pain control (patient-satisfaction) and any side-effects of intrathecal morphine. Materials and Methods After the Ethics Committee of Faculty of Medicine, Khon Kaen University approved our research protocol, we retrospectively reviewed a 6-month period (January-June, 2004) medical records from the Acute Pain Service (APS) database. All of the patients who had received intrathecal morphine for postoperative pain management were included in this study. We recorded the age and sex of the patients, the operated site and the department of service. The quality of pain control reported by the patients on the first postoperative day was accomplished-using either the Numeric Rating Scale (NRS) or the Verbal Rating Scale (VRS) at rest, evoked, highest and lowest in the first 24 postoperative hours. The dosage of intrathecal morphine used and side-effects on the first postoperative day were also recorded. A four-point scale was used to grade the level of patient-satisfaction. The operational definitions of outcomes are as the followings: I. Quality of pain control Assessed pain score using NRS (0-10) or VRS was categorized as : no pain = NRS 0, VRS no pain mild 5 = NRS 4, VRS mild moderate = NRS 5-6, VRS moderate severe = NRS 7, VRS severe II. Side-effects were : a. Respiratory depression = respiratory rate < 8 times per minute 6 b. Sedation 7 = sedation score = 3 (0 = fully alert, 1 = drowsy, 2 = asleep but easily aroused, 3 = unconscious) c. Nausea/Vomiting 7 = nausea/vomiting grade > 0 (0 = no symptom ; 1 = minimal, no Vol. 33, No. 2, April-June 2007 Thai Journal of Anesthesiology 103

3 treatment ; 2 = moderate, treatment needed ; 3 = severe, no response to treatment) d. Pruritus = the presence of any degree of pruritus e. Urinary retention = inability to void within 6 hrs after operation III. Level of satisfaction Global satisfaction with postoperative pain management using intrathecal morphine was categorized as : 1 = very unsatisfactory 2 = mildly unsatisfactory 3 = mildly satisfactory 4 = very satisfactory Statistical analysis The data were analyzed using, and presented as, descriptive statistics. Categorical variables were presented as percentages. Results The study included 274 patients. The demographic data are presented in Table 1. The two most common surgical sites was the lower abdomen (for cesarean section) and extremities. The dose of intrathecal morphine ranged between 0.1 and 0.5 mg. A dosage of 0.2 mg was the most commonly used. (Table 2) On the first postoperative day, the patientsʼ pain scores at rest rated as mild, moderate and severe were 76.7%, 17.3% and 5.9%, respectively. Regarding evoked pain, 36.7% rated their pain as mild, 29.3% as moderate and 34.0% as severe. The number of patients reported the highest and lowest pain scores in the first 24 hrs are presented in Table 3. Data were missing for the pain assessment in 51 patients (18.6%) and 14 (5.1%) were discharged before their APS visit. The dosages of morphine used and the quality of pain control for each department of service were varied Table 1 Demographic data Sex Data Number (n = 274) (%) Male 81 (29.6) Female 193 (70.4) Age (years) (0) (0.4) (1.5) (74.1) (12.8) > (11.3) Department of service General surgery 37 (13.5) Cardiothoracic surgery 1 (0.4) Urology 17 (6.2) Plastic surgery 1 (0.4) Orthopedic surgery 46 (16.8) Obstetrics and gynecology 172 (62.8) Site of operation Upper abdomen (liver) 1 (0.4) Upper abdomen (others) 3 (1.1) Lower abdomen (kidney) 18 (6.6) Lower abdomen (C/S) 155 (56.6) Lower abdomen (others) 28 (10.2) Thoracotomy 1 (0.4) Extremities 55 (20.1) Others 13 (4.7) Table 2 Dosage of intrathecal morphine used Dose (mg) Number (n = 274) (%) (0.7) (2.2) (81.4) (3.3) (10.9) (0) Others (0.18, 0.5) 2, 2 (1.5) 104 «ªï Ë 33 Ë 2 π- ÿπ π 2550

4 Table 3 Quality of pain control on the first postoperative day Pain Rest Evoked Highest in 24 hrs Lowest in 24 hrs assessment (n = 202) (%) (n = 188) (%) (n = 197) (%) (n = 189) (%) No pain 59 (29.2) 23 (12.2) 18 (9.1) 84 (44.4) Mild 96 (47.5) 46 (24.5) 43 (21.8) 83 (43.9) Moderate 35 (17.3) 55 (29.3) 50 (25.4) 17 (8.9) Severe 12 (5.9) 64 (34.0) 86 (43.7) 5 (2.7) Table 4 Dosage of intrathecal morphine and quality of pain control for each department of service Department of no. of cases Most common morphine Pain assessment (%) service (%) dose (mg) (%) at rest evoked highest in 24 hrs lowest in 24 hrs General 37 (13.5) 0.2 (51.4) mild (88.9) mild (42.9) mild (41.7) mild (91.3) Cardiothoracic 1 (0.4) 0.3 (100) mild (100) severe (100) severe (100) mild (100) Urology 17 (6.2) 0.2 (70.6) mild (100) mild (76.9) mild (53.9) mild (100) Orthopedic 46 (16.8) 0.2 (69.6) mild (73.9) mild (52.4) severe (47.8) mild (86.4) Obstetric & 172 (62.8) 0.2 (92.4) mild (72.5) severe (38.6) severe (48.5) mild (86.9) gynecology (Table 4). Pruritus (23.4%) and nausea/vomiting (23.0%) were the most common side-effects, but they were mild and easily managed. Other side-effects included urinary retention (2.7%) and dizziness (2.9%) (Table 5). We found neither respiratory depression nor other serious complications as a result of using this technique. Patient-satisfaction in terms of pain relief rated as very satisfactory, mildly satisfactory, mildly unsatisfactory and very unsatisfactory were 73.2%, 22.6%, 2.6% and 1.6%, respectively. However, 84 of the satisfaction assessments were not performed or missing (Table 6). Table 5 Incidence of side-effects Side-effect Number (n = 274) (%) Sedation 1 (0.4) Nausea/vomiting 63 (23) Pruritus 64 (23.4) Urinary retention 6/n = 225* (2.7)* Others : dizziness 8 (2.9) Foleyʼ s catheter retained 49 (17.9) Discharge before APS visit 14 (5.1) *Exclude patients who retained foleyʼ s catheter during postoperative period Vol. 33, No. 2, April-June 2007 Thai Journal of Anesthesiology 105

5 Table 6 Level of patient-satisfaction Satisfaction Number (n = 190) (%) Very satisfactory 139 (73.2) Mildly satisfactory 43 (22.6) Mildly unsatisfactory 5 (2.6) Very unsatisfactory 3 (1.6) N/A 84 (30.7) Conclusion Intrathecal morphine was used for postoperative pain control by the APS at Srinagarind Hospital with no serious side-effects and an overall high degree of patientsatisfaction. Acknowledgement We thank Mr. Bryan Roderick Hamman for assistance with the English-language presentation of this manuscript. Discussion Our results indicate that 0.2 mg of intrathecal morphine was the most commonly used and effective for postoperative pain treatment in general and urologic surgeries. According to the number of patients having severe pain in the first 24 hrs, pain relief was inadequate for obstetric and gynecologic, and orthopedic surgeries. Previous studies 7-9 reported that the effective dose of intrathecal morphine for cesarean section varied between 0.1 and 0.4 mg. Increasing the dosage would increase the amount of pain controlled, it would be offset by a concomitant increase in side-effects For service improvement, the APS must find an optimal dose for pain control for each type of surgery and each individual. During the study, we encountered neither respiratory depression nor excessive sedation. However, the sample size might have been too small to represent these less frequent complications. 14 The two most common complications were nausea/vomiting and pruritus; similar to the incidence reported by Sarvela et al. 15 The incidence of urinary retention was 2.7%. Since the urinary catheter was retained postoperatively in 17.9% of our patients, the incidence may not be accurate. Seventy-three percent of our patients were very satisfied with this technique in contrast to three (1.6%) who were very unsatisfied (two because of pain experienced during block and one because of severe nausea/ vomiting and pruritus). References 1. Behar M, Olshwang D, Magora F, Davidson JT. Epidural morphine in treatment of pain. Lancet 1979 ; 1 : Wang JK, Nauss LA, Thomas JE. Pain relief by intrathecally applied morphine in man. Anesthesiology 1979 ; 50 : Chadwick HS, Ready LB. Intrathecal and epidural morphine sulfate for postcesarean analgesia : a clinical comparison. Anesthesiology 1988 ; 68 : Sinatra RS, Ayoub CM. Postoperative analgesia : epidural and spinal techniques. In : Chestnut DH, editor. Obstetric anesthesia : principles and practice. 2 nd ed. St. Louise : Mosby, 1999 : Pongjanyakul S, Sathitkanmanee A, Rakpong P, Jangsem K, Krisanaprakornkit V, Theinthong S. Can structured instruction improve the success rate of pain assessment in PACU? Thai J Anesthesiol 2004 ; 30 : Grace D, Bunting H, Milligan KR, Fee JP. Postoperative analgesia after co-administration of clonidine and morphine by the intrathecal route in patients undergoing hip replacement. Anesth Analg 1995 ; 80 : Lam KC, Chan RS, Irwin MG. Intrathecal morphine for post-cesarean section analgesia : a comparison of 3 doses. ASEAN J of Anesthesiol 2004 ; 5 : Charuluxananan S, Kyokong O, Pongpakdee K. Optimal dose of intrathecal morphine for postoperative pain relief in caesarean section. Thai J Anesthesiol 1996 ; 22 : Ratanachai P, Ungkasuwan W, Umpa K, Bunyakiat P. The comparison of intrathecal morphine dosages for postoperative analgesia in cesarean section patients. Thai J Anesthesiol 1996 ; 22 : Abboud TK, Dror A, Mosaad P, Zhu J, Mantilla M, Swart F, et al. Mini-dose intrathecal morphine for the relief of postcesarean section pain : safety, efficacy and ventilatory responses to carbon dioxide. Anesth Analg 1988 ; 67 : «ªï Ë 33 Ë 2 π- ÿπ π 2550

6 11. Milner AR, Bogod DG, Harwood RJ. Intrathecal administration of morphine for elective cesarean section. A comparison between 0.1 mg and 0.2 mg. Anaesthesia 1996 ; 51 : Gerancher JC, Floyd H, Eisenach J. Determination of an effective dose of intrathecal morphine for pain relief after cesarean delivery. Anesth Analg 1999 ; 88 : Swart M, Sewell J, Thomas D. Intrathecal morphine for cesarean section : an assessment of pain relief, satisfaction and side-effects. Anaesthesia 1997 ; 52 : Gwirtz KH, Young JV, Byers RS, Alley C, Levin K, Walker SG et al. The safety and efficacy of intrathecal opioid analgesia for acute postoperative pain : seven years experience with 5,969 surgical patients at Indiana University Hospital. Anesth Analg 1999 ; 88 : Sarvela J, Halonen P, Soikkeli A, Korttila K. A doubleblinded, randomized comparison of intrathecal and epidural morphine for elective cesarean delivery. Anesth Analg 2002 ; 95 : Vol. 33, No. 2, April-June 2007 Thai Journal of Anesthesiology 107

7 The Efficacy and Safety of Intrathecal Morphine for Postoperative Pain Management in Srinagarind Hospital Abstract Background : Neuraxial analgesia has proven an effective means of achieving postoperative pain control, with minimal exposure to opioids in patients. Morphine has been used both epidurally and intrathecally for this purpose. Notwithstanding, we use intrathecal opioids for postoperative analgesia at our hospital. Objectives : To study the quality of pain control, the incidence of side-effects and patient-satisfaction with the intrathecal morphine used for postoperative pain management at Srinagarind Hospital. Materials & methods : We retrospectively reviewed a 6-month period (January-June, 2004) of the medical database of the Acute Pain Service (APS). All of the patients who had received intrathecal morphine for postoperative pain management were studied. We recorded demographic data including age, sex, site of operation and department of service. The quality of pain control was reported by patients using either a Numeric Rating Scale (NRS) or a Verbal Rating Scale (VRS). The dosage of intrathecal morphine used and any side-effects on the first postoperative day were recorded. A four-point scale was used to grade the level of patient-satisfaction. Results : We included 274 patients in this study, most of whom (57%) had undergone lower abdominal surgery (i.e. cesarean section). A dosage of 0.2 mg of preservative-free intrathecal morphine was the most commonly used (81%) analgesic. On the first postoperative day, 77% of the patients rated their pain at rest as mild, 17% as moderate and 5.9% as severe. Vis-a-vis evoked pain, 37% of the patients rated their pain as mild, 29% as moderate and 34% as severe. Forty-three percent of the patients indicated that the highest level of pain within the first 24 hrs was ʻsevereʼ. In terms of side-effects, pruritus (23%) and nausea/vomiting (23%) were most common, mostly ʻmildʼ and easily managed. No respiratory depression or serious complication occurred. The level of satisfaction in terms of pain relief was 73%. Conclusion : Intrathecal morphine was used in our patients for postoperative pain management with no serious side-effects and ʻhighʼ patient-satisfaction. Keywords : Intrathecal morphine, postoperative pain 108 «ªï Ë 33 Ë 2 π- ÿπ π 2550