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The influence of preemptive spinal anesthesia on postoperative pain
Original Contributions The Influence of Preemptive Spinal Anesthesia on Postoperative Pain Sonia J. Vaida, MD,* Bruce Ben-David, MD,† Mostafa Somri, MD,* Milian Croitoru, MD,* Edmond Sabo, MD,‡ Luis Gaitini, MD,* Anesthesia Department and Statistics Department, Bnai-Zion Medical Center, Haifa, Israel and Anesthesia Department, Allegheny General Hospital, Pittsburgh, PA.
*Senior Anesthesiologist, Bnai-Zion Medical Center; Haifa, Israel
Study Objective: To examine the influence of spinal anesthesia on postoperative pain and postoperative opioid requirements. Design: Prospective randomized study. Setting: Bnai-Zion Medical Center, Haifa, Israel—a government hospital. Measurements and Main Results: 30 ASA physical status I and II unpremedicated women undergoing elective total abdominal hysterectomy were randomly allocated into two groups of 15 patients each using a sealed envelope technique. Patients in Group 1 were given a subarachnoid injection of 12 mg hyperbaric bupivacaine and after 10 minutes general anesthesia was induced. Patients in Group 2 received only general anesthesia. Anesthesia was induced with midazolam and maintained with oxygen, N2O, isoflurane, and pancuronium. No opioids were given intraoperatively. Postoperatively patientcontrolled analgesia (PCA) with morphine was initiated in both groups (1 mg. mL⫺1, bolus dose 1 mg, lockout interval 10 minutes, and background infusion 1 mg.mL⫺1) at patient first request for analgesic. Pain was assessed over 24 hours by cumulative morphine dose and visual analog score (VAS). Postoperative PCA morphine consumption at 2, 6, and 24 hours following patient first request for analgesic for Groups 1 and 2 were: 3.1 ⫾ 1 mg versus 7.2 ⫾ 3 mg (p ⫽ 0.04), 13.4 ⫾ 2 mg versus 17.2 ⫾ 4 mg (p ⫽ 0.03) and 35.9 ⫾ 8 mg versus 47.7 ⫾ 8 mg in Group 2 (p ⫽ 0.04). VAS scores at 4, 6, 12, and 24 hours postoperatively were not significantly different between the two groups. Conclusions: Preoperative neural blockade may reduce postoperative analgesic requirements. © 2000 by Elsevier Science Inc.
†Senior Anesthesiologist, Allegheny General Hospital, Pittsburgh, PA.
Keywords: preemptive analgesia; postoperative pain; spinal anesthesia.
‡Senior Pathologist, Statistics Department, Bnai-Zion Medical Center, Haifa, Israel
Introduction
Address correspondence to Dr. Vaida at Department of Anesthesiology, Bnai-Zion Medical Center, 47, Golomb St., POB 4940, 31048, Haifa, Israel. E-mail: sonia@netvision. net.il Received for publication November 4, 1999; revised manuscript accepted for publication June 5, 2000.
Experimental work has demonstrated that nociceptive stimuli may alter conduction between neurons within the spinal cord creating a state of hyperexcitability.1–5 By blocking the afferent barrage through pre-injury neural block with local/regional anesthesia, it is possible to prevent this central sensitization.2 “Pre-emptive analgesia” is the concept of the administering analgesia drugs or neural blockade prior to surgical injury so as to prevent the development of any “wind-up” in the nervous system and thereby reduce subsequent analgesic requirements.2,6 – 8
Journal of Clinical Anesthesia 12:374 –377, 2000 © 2000 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
0952-8180/00/$–see front matter PII S0952-8180(00)00174-4
Preemptive Spinal Anesthesis: Vaida et al.
Clinical studies in humans have provided controversial results regarding the effectiveness of regional anesthesia in preventing postoperative pain.9 –13 The aim of this study was to compare postoperative pain and patient-controlled analgesia (PCA) opioid requirements in patients having undergone elective total abdominal hysterectomy with general anesthesia alone or with spinal anesthesia in combination with general anesthesia.
Material and Methods Thirty ASA physical status I and II women undergoing elective total abdominal hysterectomy were studied. All patients gave informed consent to participate in this study, which was approved by the Bnai-Zion Medical Center Ethics Committee. The exclusion criteria were contraindication to regional anesthesia, age 70 years or greater, use of any opioid medication in the week prior to surgery, history of alcohol or drug abuse, or history of any psychiatric or neurologic abnormality. At the preoperative visit, patients were familiarized with the recordings of postoperative pain using a visual analog scale (VAS), which consisted of a 10-cm line with 0 equaling “no pain” and 10 equaling “worst pain possible.” The use of a PCA device to provide postoperative analgesia was explained to the patients at this time. No patient received premedication. The patients were randomly allocated to one of the two groups via sealed envelope assignment. Group 1 received a combined spinal-general anesthetic technique. Prior to performing the spinal anesthesia the patients received 1000 mL of lactated Ringer’s solution intravenously (IV). After a local infiltration of 2 mL of 2% lidocaine, midline puncture with a 25-gauge pencil point needle was performed at the L2-L3 interspace, with the patient in lateral decubitus position. After obtaining free flow of cerebrospinal fluid, 12 mg of hyperbaric bupivacaine was injected. After 10 minutes, if the spinal blockade reached a sensory level to pinprick testing at T4-T6, the patient was included in the protocol. A standardized general anesthetic protocol consisting of midazolam (0.2 to 0.3 mg.kg⫺1) was used for the induction of the anesthesia. Succinylcholine 1.5 mg.kg⫺1 was used to facilitate endotracheal intubation. Anesthesia was maintained with N2O/O2 in isoflurane. Paralysis was achieved with pancuronium (0.1 mg.kg⫺1) and confirmed with a nerve stimulator. The patients in Group 2 received only general anesthesia. The protocol used for general anesthesia was the same as in Group 1. PCA morphine was instituted in the postanesthesia care unit (PACU), once the patient was conscious and complaining of pain. The PCA pump (Bard PCA I, Baxter Healthcare Corp., Deerfield, IL) was set to give 1 mg.mL⫺1 morphine, 1 mg bolus dose at a lockout interval of 10 minutes, with a background infusion rate of 1 mL hr⫺1. In both groups postoperative PCA morphine consumption was assessed at 2, 6, and 24 hours following patient first request for analgesic. Assessment of pain was made at 2, 4, 6, 12, and 24 hours
Table 1. Patient Characteristics and Duration of Surgery
Age (yrs) Weight (kg) ASA physical status (I/II) Duration of surgery (min)
Group 1
Group 2
42 ⫾ 10 78 ⫾ 6 10/5 120 ⫾ 28
44 ⫾ 12 77 ⫾ 16 12/3 110 ⫾ 46
Note: Data are presented as means ⫾ SD.
post-institution of PCA. Pain was scored on VAS; 0 ⫽ no pain and 10 ⫽ worst pain possible. PCA morphine consumption was compared between the groups by unpaired Student’s t-test. Mann-Whitney test was used to compare the VAS scored and p ⬍ 0.05 was considered statistically significant.
Results Age, weight, and duration of surgery were similar in both groups (Table 1). Four patients were withdrawn from the study because of insufficient level of spinal blockade, and, therefore, an additional four patients were included to bring “n” to 15 per group. The average level of spinal block to pinprick test was T5. The time between the end of surgery and the first use of PCA was 9 ⫾ 3 minutes for Group 1 and 48 ⫾ 8 minutes for Group 2. Comparative postoperative PCA morphine consumption at 2, 6, and 24 hours following patient first request for Groups 1 and 2, were 3.1 ⫾ 1 mg versus 7.2 ⫾ 3 mg (p ⫽ 0.04), 13.4 ⫾ 2 mg versus 17.2 ⫾ 4 mg (p ⫽ 0.03), and 35.9 ⫾ 8 mg versus 47.7 ⫾ 8 mg in Group 2 (p ⫽ 0.04). The differences in postoperative PCA morphine consumption between 2 hours and 24 hours in Groups 1 and 2 were 32.8 ⫾ 8 mg and 40.5 ⫾ 8 mg, respectively (p ⫽ 0.01). Median VAS scores over the first 24 hours are shown in Figure 1. Patients in Group 1 had a significant lower pain intensity as reflected by VAS as compared with Group 2, two hours after the institution of PCA (p ⫽ 0.03).
Figure 1. Median visual analogue scale (VAC) scores versus time. J. Clin. Anesth., vol. 12, August 2000
375
Original Contributions
There were no significant differences between the two groups in VAS after 4, 6, 12, and 24 hours (p ⬎ 0.05). Postoperative sedation scores were not significantly different at any time during the study. One patient developed postdural puncture headache. In the other patients, the postoperative course was uneventful and no side effects were recorded.
Discussion This study demonstrates that the first 24 hours of PCA morphine consumption after total abdominal hysterectomy was less after combined spinal-general anesthesia than with general anesthesia alone. These results are in accordance with previous studies suggesting that preoperative neural blockade prevents noxious surgically induced stimuli from reaching the spinal cord and establishing a hyperexcitable state.9,11,14 The dorsal horn of the spinal cord has become the center of focus in acute pain therapy. In experimental studies, acute pain behavior or sensitization of dorsal horn neurons after tissue injury may be reduced by neural block with local anesthetics.15 According to this concept, persistent painful afferent input tends to produce a steadily increasing state of hyperexcitability within the spinal cord.2,15 Further stimuli potentiate the neural impulse and intensify the pain.15 Preemptive analgesia, by blocking the initial nociceptive afferent transmission, may attenuate or prevent the development of central sensitization.16 –18 This concept applied clinically suggests that intraoperative nociceptive afferent blockade should reduce postoperative pain and analgesic requirements. The total dose of analgesia consumed during a fixed period of PCA may be useful for assessing the efficacy of different pain treatments. Our study results indicate that the patients receiving spinal anesthesia before surgery needed significantly less morphine over the first 24 hours of PCA use. A significant difference in VAS pain scores between the two groups was found only after 2 hours of PCA use. At 4, 6, 12, and 24 hours there were no differences between the groups’ pain scores. It is possible that this finding reflects the effect of residual spinal anesthesia. However, it is noted that PCA was begun later in Group 1 (at the time of patient first request for analgesic) in order to eliminate the influence of residual spinal anesthesia. Consequently, pain measurements at each given time postoperatively was different between the two groups. The results of comparable VAS scores in the two groups at 4, 6, 12, and 24 hours, suggest that the patients used PCA to achieve similar levels of pain relief. Therefore, the PCA dosage differences are believed to reflect the greater need in Group 2, presumably because of spinal cord neurophysiologic differences created by the intraoperative nociception. Clinical studies of preemptive analgesia have provided controversial results.19 A number of studies have been unable to show the benefits of the preemptive neural blockade by regional anesthesia.8,12–14 Shir et al.11 demonstrated that the intraoperative blockade of sensory conduc376
J. Clin. Anesth., vol. 12, August 2000
tion using full surgical epidural analgesia with local anesthetics decreases postoperative pain. The study of Katz et al.16 performed on patients undergoing low abdominal surgery also demonstrated that preemptive lumbar epidural anesthesia reduces both postoperative pain and postoperative PCA morphine consumption. To our knowledge, only one study has examined the influence of spinal anesthesia on postoperative pain. In this article, Tverskoy et al et al.9 demonstrated the preemptive effects of local or spinal anesthesia on postoperative pain. There are many factors (e.g., extent of tissue injury, peripheral inflammatory response, development of postoperative spinal cord hyperexcitability) that influence postoperative pain and analgesic requirements. Against this multifactorial backdrop it has been difficult to tease out the isolated effect of intraoperative nociceptive blockade. Clearly, even at best this effect can be expected only to provide pain relief. Nevertheless, a substantial body of neurophysiologic evidence suggests that there should be a demonstrable effect, regardless of its clinical relevance. The present study indeed demonstrates that the preoperative administration of spinal anesthesia significantly reduces the postoperative consumption of morphine given by PCA.
References 1. Wall PD: The prevention of postoperative pain. Pain 1988;33: 289 –90. 2. Katz J, Kavanagh BP, Sandler AN et al: Pre-emptive analgesia: clinical evidence of neuropalsticity contributing to postoperative pain. Anesthesiology 1992;77:439 – 46. 3. Woolf CJ: Recent advances in the pathophysiology of acute pain. Br J Anaesth 1989;63:139 – 46. 4. McQuay HJ: Pre-emptive analgesia: a systemic review of clinical studies. Ann Med 1955;27:249 –56. 5. Wilder-Smith OH, Tassonyi E, Senly C, Otten P, Arendt-Nielsen L: Surgical pain is followed not only by spinal sensitivization but also by supraspinal antinociception. Br J Anaesth 1996;74:566 –7. 6. McQuay HJ: Pre-emptive analgesia. Br J Anaesth 1992;69:1–3. 7. Collins R, Brandner B, Bromley LM, Woolf CJ: Is there any clinical advantage of increasing the pre-emptive dose of morphine or combining pre-incisional with postoperative morphine administration? Br J Anaesth 1995;74:396 –9. 8. Kissin I: Pre-emptive analgesia. Why its effect is not always obvious. Anesthesiology 1996;84:1015–9. 9. Tverskoy M, Cozacov C, Ayache M, Brandley EL Jr, Kissin I: Postoperative pain after inguinal herniorrhaphy with different types of anesthesia. Anesth Analg 1990;70:29 –35. 10. Pryle BJ, Vanner RG, Enriquez N, Reynolds F: Can pre-emptive lumbar epidural blockade reduce postoperative pain following lower abdominal surgery? Anaesthesia 1993;48:120 –3. 11. Shir Y, Raja SN, Frank SM: The effect of epidural versus general anesthesia on postoperative pain and analgesic requirements in patients undergoing radical prostatectomy. Anesthesiology 1994; 80:49 –56. 12. Dahl JB, Hansen BL, Hjortso NC, Erichsen J, Moiniche S, Kehlet H: Influence of timing on the effect of continuous extradural analgesia with bupivacaine and morphine after major abdominal surgery. Br J Anaesth 1992;69:4 – 8.
Preemptive Spinal Anesthesis: Vaida et al. 13. Richards JT, Read JR, Chambers WA: Epidural anaesthesia as a method of pre-emptive analgesia for abdominal hysterectomy. Anaesthesia 1998;53:296 –8. 14. Rice LJ, Pudimat MA, Hannallah RS: Timing of caudal block placement in relation to surgery does not affect duration of postoperative analgesia in paediatric ambulatory patients. Can J Anaesth 1990;37(4 pt 1):429 –31. 15. Woolf CJ, Chong MS: Pre-emptive analgesia—treating postoperative pain by preventing the establishment of central sensitization. Anesth Analg 1993;77:362–79.
16. Katz J, Clairoux M, Kavanagh BP, et al: Pre-emptive lumbar epidural anaesthesia reduces postoperative pain and patientcontrolled morphine consumption after lower abdominal surgery. Pain 1994;59:395– 403. 17. McQuay HJ, Dickenson AH: Implications of nervous system plasticity for pain management. Anaesthesia 1990;45:101–2. 18. Dahl JB, Kehlet H: The value of pre-emptive analgesia in the treatment of postoperative pain. Br J Anaesth 1993;70:434 –9. 19. Kehlet H: Postoperative pain relief—what is the issue? Br J Anaesth 1994;72:375– 8.
Preoperative Pain After Inguinal Herniorrhaphy with Different Types of Anesthesia M. Tverskoy, C. Cozacov, M. Ayache, E. L. Bradley, Jr, I. Kissin Department of Anesthesiology, Rebecca Sieff Government Hospital, Safed, Israel Abstract: In a randomized, double-blind study, postoperative pain was assessed in 36 patients undergoing inguinal herniorrhaphy with three types of anesthesia: general (thiopental-nitrous oxide-halothane); general with the addition of local (infiltration of the abdominal wall with 0.25% bupivacaine along the line of the proposed incision); and spinal (0.5% bupivacaine). The severity of constant incisional pain, movementassociated incisional pain, and pain upon pressure applied to the surgical wound using an algometer was assessed with a visual analog self-rating method at 24 hours, 48 hours, and 10 days after surgery. The addition of local anesthesia significantly decreased the intensity of all types of postoperative pain. This effect was especially evident with constant incisional pain that disappeared almost completely 24 hours after surgery. With pain caused by pressure on the site of the surgical incision, the pain score difference between general and general plus local anesthesia was obvious even 10 days after the surgery (with 0.4-kg/cm2 pressure, the pain scores were 16 ⫾ 3 vs 2 ⫾ 1, p ⬍ 0.01). The difference in postoperative pain scores between spinal and general anethesia groups indicated that spinal anethesia also decreases the pain intensity. However, this decrease is less pronounced than that seen with the addition of local anesthesia: movement-associated pain scores 24 hours after surgery were 72 ⫾ 5 in the general anesthesia group, 40 ⫾ 6 in the spinal anesthesia group, and 16 ⫾ 3 in the general plus local anesthesia group (with p ⬍ 0.002 between the groups). Reprinted with permission from Anesthesia and Analgesia 1990;70:29 –35.
J. Clin. Anesth., vol. 12, August 2000
377
*Senior Anesthesiologist, Bnai-Zion Medical Center; Haifa, Israel
Study Objective: To examine the influence of spinal anesthesia on postoperative pain and postoperative opioid requirements. Design: Prospective randomized study. Setting: Bnai-Zion Medical Center, Haifa, Israel—a government hospital. Measurements and Main Results: 30 ASA physical status I and II unpremedicated women undergoing elective total abdominal hysterectomy were randomly allocated into two groups of 15 patients each using a sealed envelope technique. Patients in Group 1 were given a subarachnoid injection of 12 mg hyperbaric bupivacaine and after 10 minutes general anesthesia was induced. Patients in Group 2 received only general anesthesia. Anesthesia was induced with midazolam and maintained with oxygen, N2O, isoflurane, and pancuronium. No opioids were given intraoperatively. Postoperatively patientcontrolled analgesia (PCA) with morphine was initiated in both groups (1 mg. mL⫺1, bolus dose 1 mg, lockout interval 10 minutes, and background infusion 1 mg.mL⫺1) at patient first request for analgesic. Pain was assessed over 24 hours by cumulative morphine dose and visual analog score (VAS). Postoperative PCA morphine consumption at 2, 6, and 24 hours following patient first request for analgesic for Groups 1 and 2 were: 3.1 ⫾ 1 mg versus 7.2 ⫾ 3 mg (p ⫽ 0.04), 13.4 ⫾ 2 mg versus 17.2 ⫾ 4 mg (p ⫽ 0.03) and 35.9 ⫾ 8 mg versus 47.7 ⫾ 8 mg in Group 2 (p ⫽ 0.04). VAS scores at 4, 6, 12, and 24 hours postoperatively were not significantly different between the two groups. Conclusions: Preoperative neural blockade may reduce postoperative analgesic requirements. © 2000 by Elsevier Science Inc.
†Senior Anesthesiologist, Allegheny General Hospital, Pittsburgh, PA.
Keywords: preemptive analgesia; postoperative pain; spinal anesthesia.
‡Senior Pathologist, Statistics Department, Bnai-Zion Medical Center, Haifa, Israel
Introduction
Address correspondence to Dr. Vaida at Department of Anesthesiology, Bnai-Zion Medical Center, 47, Golomb St., POB 4940, 31048, Haifa, Israel. E-mail: sonia@netvision. net.il Received for publication November 4, 1999; revised manuscript accepted for publication June 5, 2000.
Experimental work has demonstrated that nociceptive stimuli may alter conduction between neurons within the spinal cord creating a state of hyperexcitability.1–5 By blocking the afferent barrage through pre-injury neural block with local/regional anesthesia, it is possible to prevent this central sensitization.2 “Pre-emptive analgesia” is the concept of the administering analgesia drugs or neural blockade prior to surgical injury so as to prevent the development of any “wind-up” in the nervous system and thereby reduce subsequent analgesic requirements.2,6 – 8
Journal of Clinical Anesthesia 12:374 –377, 2000 © 2000 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
0952-8180/00/$–see front matter PII S0952-8180(00)00174-4
Preemptive Spinal Anesthesis: Vaida et al.
Clinical studies in humans have provided controversial results regarding the effectiveness of regional anesthesia in preventing postoperative pain.9 –13 The aim of this study was to compare postoperative pain and patient-controlled analgesia (PCA) opioid requirements in patients having undergone elective total abdominal hysterectomy with general anesthesia alone or with spinal anesthesia in combination with general anesthesia.
Material and Methods Thirty ASA physical status I and II women undergoing elective total abdominal hysterectomy were studied. All patients gave informed consent to participate in this study, which was approved by the Bnai-Zion Medical Center Ethics Committee. The exclusion criteria were contraindication to regional anesthesia, age 70 years or greater, use of any opioid medication in the week prior to surgery, history of alcohol or drug abuse, or history of any psychiatric or neurologic abnormality. At the preoperative visit, patients were familiarized with the recordings of postoperative pain using a visual analog scale (VAS), which consisted of a 10-cm line with 0 equaling “no pain” and 10 equaling “worst pain possible.” The use of a PCA device to provide postoperative analgesia was explained to the patients at this time. No patient received premedication. The patients were randomly allocated to one of the two groups via sealed envelope assignment. Group 1 received a combined spinal-general anesthetic technique. Prior to performing the spinal anesthesia the patients received 1000 mL of lactated Ringer’s solution intravenously (IV). After a local infiltration of 2 mL of 2% lidocaine, midline puncture with a 25-gauge pencil point needle was performed at the L2-L3 interspace, with the patient in lateral decubitus position. After obtaining free flow of cerebrospinal fluid, 12 mg of hyperbaric bupivacaine was injected. After 10 minutes, if the spinal blockade reached a sensory level to pinprick testing at T4-T6, the patient was included in the protocol. A standardized general anesthetic protocol consisting of midazolam (0.2 to 0.3 mg.kg⫺1) was used for the induction of the anesthesia. Succinylcholine 1.5 mg.kg⫺1 was used to facilitate endotracheal intubation. Anesthesia was maintained with N2O/O2 in isoflurane. Paralysis was achieved with pancuronium (0.1 mg.kg⫺1) and confirmed with a nerve stimulator. The patients in Group 2 received only general anesthesia. The protocol used for general anesthesia was the same as in Group 1. PCA morphine was instituted in the postanesthesia care unit (PACU), once the patient was conscious and complaining of pain. The PCA pump (Bard PCA I, Baxter Healthcare Corp., Deerfield, IL) was set to give 1 mg.mL⫺1 morphine, 1 mg bolus dose at a lockout interval of 10 minutes, with a background infusion rate of 1 mL hr⫺1. In both groups postoperative PCA morphine consumption was assessed at 2, 6, and 24 hours following patient first request for analgesic. Assessment of pain was made at 2, 4, 6, 12, and 24 hours
Table 1. Patient Characteristics and Duration of Surgery
Age (yrs) Weight (kg) ASA physical status (I/II) Duration of surgery (min)
Group 1
Group 2
42 ⫾ 10 78 ⫾ 6 10/5 120 ⫾ 28
44 ⫾ 12 77 ⫾ 16 12/3 110 ⫾ 46
Note: Data are presented as means ⫾ SD.
post-institution of PCA. Pain was scored on VAS; 0 ⫽ no pain and 10 ⫽ worst pain possible. PCA morphine consumption was compared between the groups by unpaired Student’s t-test. Mann-Whitney test was used to compare the VAS scored and p ⬍ 0.05 was considered statistically significant.
Results Age, weight, and duration of surgery were similar in both groups (Table 1). Four patients were withdrawn from the study because of insufficient level of spinal blockade, and, therefore, an additional four patients were included to bring “n” to 15 per group. The average level of spinal block to pinprick test was T5. The time between the end of surgery and the first use of PCA was 9 ⫾ 3 minutes for Group 1 and 48 ⫾ 8 minutes for Group 2. Comparative postoperative PCA morphine consumption at 2, 6, and 24 hours following patient first request for Groups 1 and 2, were 3.1 ⫾ 1 mg versus 7.2 ⫾ 3 mg (p ⫽ 0.04), 13.4 ⫾ 2 mg versus 17.2 ⫾ 4 mg (p ⫽ 0.03), and 35.9 ⫾ 8 mg versus 47.7 ⫾ 8 mg in Group 2 (p ⫽ 0.04). The differences in postoperative PCA morphine consumption between 2 hours and 24 hours in Groups 1 and 2 were 32.8 ⫾ 8 mg and 40.5 ⫾ 8 mg, respectively (p ⫽ 0.01). Median VAS scores over the first 24 hours are shown in Figure 1. Patients in Group 1 had a significant lower pain intensity as reflected by VAS as compared with Group 2, two hours after the institution of PCA (p ⫽ 0.03).
Figure 1. Median visual analogue scale (VAC) scores versus time. J. Clin. Anesth., vol. 12, August 2000
375
Original Contributions
There were no significant differences between the two groups in VAS after 4, 6, 12, and 24 hours (p ⬎ 0.05). Postoperative sedation scores were not significantly different at any time during the study. One patient developed postdural puncture headache. In the other patients, the postoperative course was uneventful and no side effects were recorded.
Discussion This study demonstrates that the first 24 hours of PCA morphine consumption after total abdominal hysterectomy was less after combined spinal-general anesthesia than with general anesthesia alone. These results are in accordance with previous studies suggesting that preoperative neural blockade prevents noxious surgically induced stimuli from reaching the spinal cord and establishing a hyperexcitable state.9,11,14 The dorsal horn of the spinal cord has become the center of focus in acute pain therapy. In experimental studies, acute pain behavior or sensitization of dorsal horn neurons after tissue injury may be reduced by neural block with local anesthetics.15 According to this concept, persistent painful afferent input tends to produce a steadily increasing state of hyperexcitability within the spinal cord.2,15 Further stimuli potentiate the neural impulse and intensify the pain.15 Preemptive analgesia, by blocking the initial nociceptive afferent transmission, may attenuate or prevent the development of central sensitization.16 –18 This concept applied clinically suggests that intraoperative nociceptive afferent blockade should reduce postoperative pain and analgesic requirements. The total dose of analgesia consumed during a fixed period of PCA may be useful for assessing the efficacy of different pain treatments. Our study results indicate that the patients receiving spinal anesthesia before surgery needed significantly less morphine over the first 24 hours of PCA use. A significant difference in VAS pain scores between the two groups was found only after 2 hours of PCA use. At 4, 6, 12, and 24 hours there were no differences between the groups’ pain scores. It is possible that this finding reflects the effect of residual spinal anesthesia. However, it is noted that PCA was begun later in Group 1 (at the time of patient first request for analgesic) in order to eliminate the influence of residual spinal anesthesia. Consequently, pain measurements at each given time postoperatively was different between the two groups. The results of comparable VAS scores in the two groups at 4, 6, 12, and 24 hours, suggest that the patients used PCA to achieve similar levels of pain relief. Therefore, the PCA dosage differences are believed to reflect the greater need in Group 2, presumably because of spinal cord neurophysiologic differences created by the intraoperative nociception. Clinical studies of preemptive analgesia have provided controversial results.19 A number of studies have been unable to show the benefits of the preemptive neural blockade by regional anesthesia.8,12–14 Shir et al.11 demonstrated that the intraoperative blockade of sensory conduc376
J. Clin. Anesth., vol. 12, August 2000
tion using full surgical epidural analgesia with local anesthetics decreases postoperative pain. The study of Katz et al.16 performed on patients undergoing low abdominal surgery also demonstrated that preemptive lumbar epidural anesthesia reduces both postoperative pain and postoperative PCA morphine consumption. To our knowledge, only one study has examined the influence of spinal anesthesia on postoperative pain. In this article, Tverskoy et al et al.9 demonstrated the preemptive effects of local or spinal anesthesia on postoperative pain. There are many factors (e.g., extent of tissue injury, peripheral inflammatory response, development of postoperative spinal cord hyperexcitability) that influence postoperative pain and analgesic requirements. Against this multifactorial backdrop it has been difficult to tease out the isolated effect of intraoperative nociceptive blockade. Clearly, even at best this effect can be expected only to provide pain relief. Nevertheless, a substantial body of neurophysiologic evidence suggests that there should be a demonstrable effect, regardless of its clinical relevance. The present study indeed demonstrates that the preoperative administration of spinal anesthesia significantly reduces the postoperative consumption of morphine given by PCA.
References 1. Wall PD: The prevention of postoperative pain. Pain 1988;33: 289 –90. 2. Katz J, Kavanagh BP, Sandler AN et al: Pre-emptive analgesia: clinical evidence of neuropalsticity contributing to postoperative pain. Anesthesiology 1992;77:439 – 46. 3. Woolf CJ: Recent advances in the pathophysiology of acute pain. Br J Anaesth 1989;63:139 – 46. 4. McQuay HJ: Pre-emptive analgesia: a systemic review of clinical studies. Ann Med 1955;27:249 –56. 5. Wilder-Smith OH, Tassonyi E, Senly C, Otten P, Arendt-Nielsen L: Surgical pain is followed not only by spinal sensitivization but also by supraspinal antinociception. Br J Anaesth 1996;74:566 –7. 6. McQuay HJ: Pre-emptive analgesia. Br J Anaesth 1992;69:1–3. 7. Collins R, Brandner B, Bromley LM, Woolf CJ: Is there any clinical advantage of increasing the pre-emptive dose of morphine or combining pre-incisional with postoperative morphine administration? Br J Anaesth 1995;74:396 –9. 8. Kissin I: Pre-emptive analgesia. Why its effect is not always obvious. Anesthesiology 1996;84:1015–9. 9. Tverskoy M, Cozacov C, Ayache M, Brandley EL Jr, Kissin I: Postoperative pain after inguinal herniorrhaphy with different types of anesthesia. Anesth Analg 1990;70:29 –35. 10. Pryle BJ, Vanner RG, Enriquez N, Reynolds F: Can pre-emptive lumbar epidural blockade reduce postoperative pain following lower abdominal surgery? Anaesthesia 1993;48:120 –3. 11. Shir Y, Raja SN, Frank SM: The effect of epidural versus general anesthesia on postoperative pain and analgesic requirements in patients undergoing radical prostatectomy. Anesthesiology 1994; 80:49 –56. 12. Dahl JB, Hansen BL, Hjortso NC, Erichsen J, Moiniche S, Kehlet H: Influence of timing on the effect of continuous extradural analgesia with bupivacaine and morphine after major abdominal surgery. Br J Anaesth 1992;69:4 – 8.
Preemptive Spinal Anesthesis: Vaida et al. 13. Richards JT, Read JR, Chambers WA: Epidural anaesthesia as a method of pre-emptive analgesia for abdominal hysterectomy. Anaesthesia 1998;53:296 –8. 14. Rice LJ, Pudimat MA, Hannallah RS: Timing of caudal block placement in relation to surgery does not affect duration of postoperative analgesia in paediatric ambulatory patients. Can J Anaesth 1990;37(4 pt 1):429 –31. 15. Woolf CJ, Chong MS: Pre-emptive analgesia—treating postoperative pain by preventing the establishment of central sensitization. Anesth Analg 1993;77:362–79.
16. Katz J, Clairoux M, Kavanagh BP, et al: Pre-emptive lumbar epidural anaesthesia reduces postoperative pain and patientcontrolled morphine consumption after lower abdominal surgery. Pain 1994;59:395– 403. 17. McQuay HJ, Dickenson AH: Implications of nervous system plasticity for pain management. Anaesthesia 1990;45:101–2. 18. Dahl JB, Kehlet H: The value of pre-emptive analgesia in the treatment of postoperative pain. Br J Anaesth 1993;70:434 –9. 19. Kehlet H: Postoperative pain relief—what is the issue? Br J Anaesth 1994;72:375– 8.
Preoperative Pain After Inguinal Herniorrhaphy with Different Types of Anesthesia M. Tverskoy, C. Cozacov, M. Ayache, E. L. Bradley, Jr, I. Kissin Department of Anesthesiology, Rebecca Sieff Government Hospital, Safed, Israel Abstract: In a randomized, double-blind study, postoperative pain was assessed in 36 patients undergoing inguinal herniorrhaphy with three types of anesthesia: general (thiopental-nitrous oxide-halothane); general with the addition of local (infiltration of the abdominal wall with 0.25% bupivacaine along the line of the proposed incision); and spinal (0.5% bupivacaine). The severity of constant incisional pain, movementassociated incisional pain, and pain upon pressure applied to the surgical wound using an algometer was assessed with a visual analog self-rating method at 24 hours, 48 hours, and 10 days after surgery. The addition of local anesthesia significantly decreased the intensity of all types of postoperative pain. This effect was especially evident with constant incisional pain that disappeared almost completely 24 hours after surgery. With pain caused by pressure on the site of the surgical incision, the pain score difference between general and general plus local anesthesia was obvious even 10 days after the surgery (with 0.4-kg/cm2 pressure, the pain scores were 16 ⫾ 3 vs 2 ⫾ 1, p ⬍ 0.01). The difference in postoperative pain scores between spinal and general anethesia groups indicated that spinal anethesia also decreases the pain intensity. However, this decrease is less pronounced than that seen with the addition of local anesthesia: movement-associated pain scores 24 hours after surgery were 72 ⫾ 5 in the general anesthesia group, 40 ⫾ 6 in the spinal anesthesia group, and 16 ⫾ 3 in the general plus local anesthesia group (with p ⬍ 0.002 between the groups). Reprinted with permission from Anesthesia and Analgesia 1990;70:29 –35.
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