Intraoperative Epidural Analgesia Combined with Ketamine Provides Effective Preventive Analgesia in Patients Undergoing Major Digestive Surgery

Background: As a broader definition of preemptive analgesia, preventive analgesia aims to prevent the sensitization of central nervous system, hence the development of pathologic pain after tissular injury. To demonstrate benefits from preventive treatment, objective measurement of postoperative pain such as wound hyperalgesia and persistent pain should be evaluated. The current study assessed the role and timing of epidural analgesia in this context.

Methods: In a randomized, double-blinded trial, 85 patients scheduled to undergo neoplastic colonic resection were included. All the patients received a thoracic epidural catheter, systemic ketamine at a antihyperalgesic dose, and general anesthesia. Continuous infusion of analgesics belonging to the same class was administered by either intravenous or epidural route before incision until 72 h after surgery. Patients were allocated to four groups to receive intraoperative intravenous lidocaine-sufentanil-clonidine or epidural bupivacaine-sufentanil-clonidine followed postoperatively by either intravenous (lidocaine-morphine-clonidine) or epidural (bupivacaine-sufentanil-clonidine) patient-controlled analgesia. Postoperative pain scores (visual analog scale), analgesic consumption, wound area of punctuate hyperalgesia, residual pain, and analgesics needed from 2 weeks until 12 months were recorded.

Results: Analgesic requirements, visual analog scale scores, and area of hyperalgesia were significantly higher in the intravenous treatment group (intravenous-intravenous), and more patients reported residual pain from 2 weeks until 1 yr (28%). Although postoperative pain measurements did not differ, postoperative epidural treatment (intravenous-epidural) was less effective to prevent residual pain at 1 yr (11%; P = 0.2 with intravenous-intravenous group) than intraoperative one (epidural-epidural and epidural-intravenous groups) (0%; P = 0.01 with intravenous-intravenous group).     

The use of intraoperative epidural or spinal analgesia modulates postoperative hyperalgesia and reduces residual pain after major abdominal surgery

INTRODUCTION: The use of intraoperative multimodal analgesia has clearly improved postoperative pain control, mortality and morbidity after major surgical procedures. However, very few clinical trials have studied the longterm impact of intraoperative epidural or spinal analgesia on chronic postsurgical pain (CPSP) development. Even less studies have evaluated the modulatory effect of intraoperative neuraxial analgesia on objective changes (i.e. mechanical hyperalgesia) reflecting central sensitization. METHODS: The present work compares general anesthesia alone (GA group) versus general anesthesia combined to either intraoperative epidural analgesia (EPID group: combination of bupicavaine, sufentanil and clonidine 1 microg/kg) or spinal analgesia (IT group: either bupivacaine or clonidine 300 microg) on the development of secondary mechanical hyperalgesia and the incidence of CPSP after major abdominal surgery. Data analyzed in the present work involve adult patients undergoing surgical resection of rectal adenocarcinoma who participated in three previously published randomized trials. RESULTS: Intraoperative epidural and particularly spinal analgesia reduced both incidence (p < 0.05 between GA alone and spinal analgesia) and extent (area) of secondary mechanical hyperalgesia surrounding the wound at 48h and 72 h after surgery. The use of intraoperative epidural and spinal analgesia also reduced CPSP incidence. Postoperative area of mechanical hyperalgesia seems positively correlated with the incidence CPSP. CONCLUSION: An effective intraoperative neuraxial block of nociceptive inputs from the wound using multimodal analgesia--specifically when involving spinal analgesics and antihyperalgesic drugs--contributes to prevent central sensitization and hence reduces CPSP after major abdominal procedures.     

Preemptive analgesia by intravenous low-dose ketamine and epidural morphine in gastrectomy: a randomized double-blind study

BACKGROUND: Morphine and ketamine may prevent central sensitization during surgery and result in preemptive analgesia. The reliability of preemptive analgesia, however, is controversial. METHODS: Gastrectomy patients were given preemptive analgesia consisting of epidural morphine, intravenous low-dose ketamine, and combinations of these in a randomized, double-blind manner. Postsurgical pain intensity was rated by a visual analog scale, a categoric pain evaluation, and cumulative morphine consumption. RESULTS: Preemptive analgesia by epidural morphine and by intravenous low-dose ketamine were significantly effective but not definitive. With epidural morphine, a significant reduction in visual analog scale scores at rest was observed at 24 and 48 h, and morphine consumption was significantly lower at 6 and 12 h, compared with control values. With intravenous ketamine, visual analog scale scores at rest and morphine consumption were significantly lower at 6, 12, 24, and 48 h than those in control subjects. The combination of epidural morphine and intravenous ketamine provided definitive preemptive analgesia: Visual analog scale scores at rest and morphine consumption were significantly the lowest at 6, 12, 24, and 48 h, and the visual analog scale score during movement and the categoric pain score also were significantly the lowest among the groups. CONCLUSION: The results suggest that for definitive preemptive analgesia, blockade of opioid and N-methyl-d-aspartate receptors is necessary for upper abdominal surgery such as gastrectomy; singly, either treatment provided significant, but not definitive, postsurgical pain relief. Epidural morphine may affect the spinal cord segmentally, whereas intravenous ketamine may block brain stem sensitization via the vagus nerve during upper abdominal surgery.     

The short-lasting analgesia and long-term antihyperalgesic effect of intrathecal clonidine in patients undergoing colonic surgery

In this study, we investigated the antihyperalgesic effect of clonidine after surgery. Sixty patients undergoing right colic resection were studied. Patients were randomized to receive prior to general anesthesia a 2-mL intrathecal (IT) injection of 300 microg of clonidine or saline, or 10 mg of bupivacaine. General anesthesia was achieved using a target concentration propofol infusion and monitored using bispectral index. Postoperative analgesia was provided by morphine IV given through a patient-controlled analgesia device. Postoperative analgesia was assessed by morphine requirements and visual analog scale pain scores at rest, cough, and movement during the first 72 h. Mechanical hyperalgesia was measured by von Frey filaments. Patients were questioned regarding residual pain at 2 wk,1, 6, and 12 mo. The patient-controlled analgesia morphine requirements were significantly smaller in the IT clonidine group (31.5 +/- 12 versus 91 +/- 25.5 and 43 +/- 15 mg, respectively, in groups clonidine, saline, and bupivacaine: P < 0.05 at 72 postoperative hours). The area of hyperalgesia at 72 h was 3 +/- 5 cm(2) in the clonidine group versus 90 +/- 30 and 35 +/- 20 cm(2) in the saline and bupivacaine groups (P < 0.05). At 6 mo, fewer patients in the clonidine group experienced residual pain than in the saline group (0 of 20 versus 6 of 20, P < 0.05). We conclude that both intraoperative spinal clonidine and bupivacaine improve immediate postoperative analgesia. IT clonidine was, however, more potent than IT bupivacaine to reduce postoperative secondary hyperalgesia. IMPLICATIONS: Spinal clonidine contributes to the reduction of secondary hyperalgesia in patients recovering from abdominal surgery.     

Low-dose intravenous ketamine potentiates epidural analgesia after thoracotomy

BACKGROUND: Ketamine potentiates intravenous or epidural morphine analgesia. The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain. METHODS: Forty-nine patients scheduled to undergo open thoracotomy were randomly assigned to receive one of two anesthesia regimens: continuous epidural infusion of ropivacaine and morphine, along with intravenous infusion of ketamine (0.05 mg . kg(-1) . h(-1) [approximately 3 mg/h], ketamine group, n = 24) or placebo (saline, control group, n = 25). Epidural analgesia was continued for 2 days after surgery, and infusion of ketamine or placebo was continued for 3 days. Pain was assessed at 6, 12, 24, and 48 h after surgery. Patients were asked about their pain, abnormal sensation on the wound, and inconvenience in daily life at 7 days and 1, 3, and 6 months after surgery. RESULTS: The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group (pain at rest, 9 +/- 11 vs. 25 +/- 20 and 9 +/- 11 vs. 18 +/- 13; pain on coughing, 26 +/- 16 vs. 50 +/- 17 and 30 +/- 18 vs. 43 +/- 18, mean +/- SD; P = 0.002 and P = 0.01, P < 0.0001 and P = 0.02, respectively). The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group (0.5 [0-4] vs. 2 [0-5] and 0 [0-5] vs. 1.5 [0-6], median [range], respectively; P = 0.02). Three months after surgery, a higher number of control patients were taking pain medication (2 vs. 9; P = 0.03). CONCLUSIONS: Very-low-dose ketamine (0.05 mg . kg(-1) . h(-1)) potentiated morphine-ropivacaine analgesia and reduced postthoracotomy pain.     

术后镇痛对机体免疫功能的影响

手术创伤和术后疼痛引起机体免疫功能的改变.有效的术后镇痛可减轻机体的应激反应,减轻免疫抑型,利于机体早日康复.此篇综述了不同的镇痛药物、不同的镇痛方式(包括静脉镇痛,硬膜外镇痛和多模式镇痛)对机体术后免疫功能的影响.     

Postoperative wound oxygen tension with epidural or intravenous analgesia: a prospective,randomized, single-blind clinical trial

BACKGROUND: Adequate tissue oxygen tension is an essential requirement for surgical-wound healing. The authors tested the hypothesis that epidural anesthesia and analgesia increases wound tissue oxygen tension compared with intravenous morphine analgesia. METHODS: In a prospective, randomized, blind clinical study, the authors allocated patients having major abdominal surgery (n = 32) to receive combined general and epidural anesthesia with postoperative patient-controlled epidural analgesia (epidural group, n = 16), or general anesthesia alone with postoperative patient-controlled intravenous analgesia (intravenous group, n = 16). An oxygen sensor and a temperature sensor were placed subcutaneously in the wound before closure. Wound oxygen tension (P(w)O(2)) and temperature were measured continuously for 24 h. Other variables affecting wound tissue oxygenation and visual analogue scale (VAS) pain scores were also documented. RESULTS: Despite epidural patients having lower body temperatures at the end of surgery (35.7 +/- 0.3) versus 36.3 +/- 0.5 degrees C, = 0.004), they had significantly higher mean P(w)O(2) over the 24 h period, compared with the intravenous group (64.4 +/- 14 vs. 50.7 +/- 15) mmHg, mean (SD), 95% CI difference, -22 to -5, = 0.002). Area under the P(w)O(2) -24 h time curve was also significantly higher in the epidural group (930 +/- 278 vs. 749 +/- 257) mmHg x h, 95% CI difference -344 to -18, = 0.03). VAS pain scores at rest and moving were significantly lower in the epidural group at all times. CONCLUSION: Epidural anesthesia and postoperative analgesia for major abdominal surgery increases wound tissue oxygen tension compared with general anesthesia and intravenous morphine analgesia.     

Effects of postoperative continuous epidural analgesia after laparoscopy-assisted colectomy

BACKGROUND: This study was conducted to evaluate the effects of continuous epidural analgesia on the postoperative pain and the early recovery after laparoscopy-assisted colectomy (LAC). METHODS: A total of 50 patients undergoing elective LAC were investigated for postoperative pain score and other variables retrospectively. RESULTS: Thirty patients who had received epidural analgesia (E group) showed significantly lower pain scores for 2 and 24 hours after surgery, compared with twenty patients who had received analgesics intramuscularly or transrectally (C group). The patients in the E group needed significantly less supplemental analgesics than those in C group for 12 to 24 hours after the operation. The incidence of postoperative complications and the early recovery were not significantly different between the two groups. CONCLUSIONS: These results show that postoperative continuous epidural analgesia is effective for postoperative pain relief in patients after laparoscopy-assisted colectomy.     

Significance of patient-controlled analgesia in combination with continuous epidural block for patients who underwent posterior lumbar surgery

The purpose of the study was to evaluate the efficiency of patient-controlled analgesia (PCA) combined with continuous epidural block in patients who underwent lumbar spine surgery. In group 1 (postoperative PCA group), 23 patients were administered postoperative continuous epidural block in combination with analgesics, which was self-regulated by the patient using a device. In contrast, the 22 patients in group 2 (control group) received suppositories or intramuscular injections of analgesics on request. The following factors were compared between the two groups: pain relief according to the visual analog scale for pain assessment, the frequency of administration of analgesics, and side effects of the postoperative analgesia. The patients in group 1 had more satisfactory relief of pain according to the visual analog scale for pain assessment and needed suppositories and intramuscular injection of analgesics less frequently on the 1st, 2nd, and 3rd postoperative day. The time spent by nurses on pain management in group 1 was less than that in group 2. No patient had any serious complications in either group. In conclusion, the present patient-controlled method combined with postoperative continuous epidural block could decrease the intensity of postoperative pain and the amount of time spent by nurses on the administration of postoperative analgesics after lumbar spine surgery. Received: 17 July 1997 Revised: 30 September 1997 Accepted: 14 October 1997     

Double epidural catheter with ropivacaine versus intravenous morphine: a comparison for postoperative analgesia after scoliosis correction surgery

BACKGROUND: Major spine surgery with a dorsal or ventrodorsal approach causes severe postoperative pain. The use of continuous epidural analgesia through one or two epidural catheters placed intraoperatively by the surgeon has been shown to provide efficient postoperative pain control. In this prospective unblinded study, the authors compared the efficacy of continuous intravenous morphine with a continuous double epidural catheter technique with ropivacaine after scoliosis correction. METHODS: Thirty patients with American Society of Anesthesiology physical status I-III were prospectively randomized to either the morphine group or the epidural group. At the end of surgery, patients in the epidural group received two epidural catheters placed by the surgeon, one directed cephalad and one caudally. Correct placement was checked radiographically. Postoperative analgesia until the first postoperative morning was performed with remifentanil target-control infusion for all patients. From that time remifentanil was stopped and continuous intravenous analgesia with morphine or double epidural analgesia with ropivacaine 0.3% was initiated (T0 = beginning of study). Pain at rest and pain in motion (using a visual analog scale from 0-100), the amount of rescue analgesics, sensory level, motor blockade, postoperative nausea and vomiting, and pruritus were assessed every 6 h and bowel function was assessed every 12 h until T72 (end of study). Two days later, patient satisfaction was assessed. RESULTS: Pain scores at rest were significantly decreased in the epidural group at all time points except at T12, T60, and T72. Pain scores in motion were significantly decreased in the epidural group at T24, T48, and T72. Bowel activity was significantly better in the epidural group at T24, T36, T48, and T60. Postoperative nausea and vomiting and pruritus occurred significantly less frequently in the epidural group. No complications related to the epidural catheter occurred. CONCLUSIONS: Both methods provide efficient postoperative analgesia. However, double epidural catheter technique provides better postoperative analgesia, earlier recovery of bowel function, fewer side effects, and a higher patient satisfaction.     

Intraarticular, epidural, and intravenous analgesia after total knee arthroplasty

BACKGROUND: After total knee arthroplasty, patients regularly suffer from severe pain. It is unclear whether epidural or systemic pain therapy is superior in terms of postoperative pain relief, patients' comfort and side effects. A new therapeutic approach, intraarticular opioids, has been suggested with the detection of opioid receptors in inflamed tissue. This method has proven suitable for clinical use in small operations (e.g. knee arthroscopy). In this study, we compared epidural analgesia and intraarticular application of morphine plus "on-demand" intravenous analgesia to "on-demand" intravenous analgesia alone. METHODS: Thirty-seven patients, scheduled for total knee arthroplasty, were randomly assigned to three treatment groups: in group 1 (EPI) patients received bolus doses of morphine via an epidural catheter; in group 2 (IA) an intraarticular bolus of 1 mg of morphine was applied at the end of the operation with subsequent use of a patient-controlled analgesia (PCA) pump; group 3 (Control), in which only PCA was provided, served as control for both analgesic procedures. Main outcome measures included visual analogue pain scales, total morphine consumption, and stress hormones. RESULTS: No statistically significant differences in visual analogue pain scales could be detected between the three groups. Application of intraarticular morphine did not reduce the amount of analgesics required for postoperative analgesia as compared to intravenous analgesia alone. Application of epidural morphine significantly suppressed beta-endorphine release, but did not significantly influence other stress hormones as compared to the control group. CONCLUSION: Epidural and intravenous analgesia after total knee arthroplasty are equivalent methods of pain relief. In major orthopaedic procedures, application of intraarticular morphine does not reduce analgesic requirements.     

Intraoperative intravenous ketamine in combination with epidural analgesia: postoperative analgesia after renal surgery

We designed this double-blinded, randomized, controlled study to evaluate the effect of small-dose ketamine IV in combination with epidural morphine and bupivacaine on postoperative pain after renal surgery. An epidural catheter was inserted, and the administration of morphine and bupivacaine was started before surgery. Forty patients were assigned to one of two groups (ketamine or control). The ketamine group was administered a ketamine bolus and infusion during surgery. The median visual analog pain scale (VAS) scores at rest were significantly lower in the ketamine group during the first 6 h (P < 0.01). VAS pain scores on coughing were also significantly lower in the ketamine group (P < 0.01). Cumulative postoperative total analgesic consumption was less in the ketamine group on Days 1 and 2 (P < 0.001). The first analgesic demand time was shorter in the control group (9.2 +/- 11.5 min) than in the ketamine group (22.3 +/- 17.1 min) (P < 0.0001). The incidence of nausea and pruritus was more frequent in the control group (P < 0.05). In conclusion, postoperative analgesia was more effective when spinal cord and brain sensitization were blocked by a combination of epidural morphine/bupivacaine and IV ketamine. IMPLICATIONS: Renal nociception conducted multisegmentally by both the spinal nerves (T10 to L1) and the vagus nerve cannot be blocked by epidural analgesia alone. We demonstrated that IV ketamine had an improved analgesic or opioid-sparing effect when it was combined with epidural bupivacaine and morphine after renal surgery.     

Comparison of intravenous or epidural patient-controlled analgesia in the elderly after major abdominal surgery

BACKGROUND: Patient-controlled analgesia (PCA) with intravenous morphine and patient-controlled epidural analgesia (PCEA), using an opioid either alone or in combination with a local anesthetic, are two major advances in the management of pain after major surgery. However, these techniques have been evaluated poorly in elderly people. This prospective, randomized study compared the effectiveness on postoperative pain and safety of PCEA and PCA after major abdominal surgery in the elderly patient. METHODS: Seventy patients older than 70 yr of age and undergoing major abdominal surgery were assigned randomly to receive either combined epidural analgesia and general anesthesia followed by postoperative PCEA, using a mixture of 0.125% bupivacaine and sufentanil (PCEA group), or general anesthesia followed by PCA with intravenous morphine (PCA group). Pain intensity was tested three times daily using a visual analog scale. Postoperative evaluation included mental status, cardiorespiratory and gastrointestinal functions, and patient satisfaction scores. RESULTS: Pain relief was better at rest (P = 0.001) and after coughing (P = 0.002) in the PCEA group during the 5 postoperative days. Satisfaction scores were better in the PCEA group. Although incidence of delirium was comparable in the PCA and PCEA groups (24% vs. 26%, respectively), mental status was improved on the fourth and fifth postoperative days in the PCEA group. The PCEA group recovered bowel function more quickly than did the PCA group. Cardiopulmonary complications were similar in the two groups. CONCLUSION: After major abdominal surgery in the elderly patient, patient-controlled analgesia, regardless of the route (epidural or parenteral), is effective. The epidural route using local anesthetics and an opioid provides better pain relief and improves mental status and bowel activity.     

Pre-emptive analgesia with ketamine, morphine and epidural lidocaine prior to total knee replacement

Purpose

Pre-emptive analgesia can improve postoperative pain management. The purpose of this study was to examine the effectiveness of ketamine as a pre-emptive analgesic as previous studies have shown the involvement of N-methyl-D-Aspartate (NMDA) receptor in neuroplasticity.

Methods

Forty-five ASA 1–2 patients, undergoing unilateral total knee replacement were studied. In the study groups, epidural lidocaine was used as the primary anaesthestic. Patients received ketamine + morphine epidurally 30 min either before (group EB) or after skin incision (group EA). Group G patients received general anaesthesia and ketamine + morphine were given 30 min after skin incision via an epidural catheter used for postoperative pain control. Epidural morphine and ketamine in lidocaine was given to all patients at the end of surgery and every 12 hr for three days for analgesia supplemented with PCA morphine. The time until first PCA trigger, morphine consumption, pain scores, satisfaction scores, and morphine related side effects were recorded at 6, 12, 24, 48 and 72 hr after surgery.

Results

Epidural ketamine plus morphine with lidocaine before surgical incision produced better pain relief and patient satisfaction than when given after incision. A longer time to PCA and decreased morphine consumption were observed in group EB than in group G. In group EA, epidural anaesthesia also produced some pre-emptive analgesic effect compared with general anaesthesia shown by decreased morphine consumption.

Conclusions

Administration of ketamine plus morphine with epidural lidocaine anaesthesia before surgery provided improved postoperative analgesia compared with general anaesthesia alone or when analgesics were given after skin incision.     

Preemptive ketamine during general anesthesia for postoperative analgesia in patients undergoing laparoscopic cholecystectomy

AIM: Preemptive analgesia is currently in use in the management of postoperative pain and no more under search. The administration of ketamine as intraoperative analgesic agent is well-known since a long time; the analgesic properties of this drug are related to its actions as a non-competitive N-methyl-D-aspartate receptors antagonist; these receptors present an excitatory function on pain transmission and this binding seems to prevent or reverse the central sensitisation of every kind of pain, including postoperative pain. In literature, the use of this anesthetic for the preemptive analgesia in the management of postoperative pain is controversial; for this reason the aim of our study was the clinical evaluation of preemptive perioperative analgesia with low-doses ketamine. METHODS: This trial involved 40 patients undergoing laparoscopic cholecystectomy, with the same surgical operator; postoperative analgesia was performed with the intraoperative administration of ketamine (0.7 mg/kg) or tramadol (15 mg/kg). A randomized, double-blind study was performed; after an inhalatory/analgesic general anesthesia (sevofluorane + remifentanyl) the postoperative-pain control was clinically evaluated through algometric measurements (Visual Analog Scale, Verbal Rating Scale, Pain Intensity Difference); supplemental doses of tramadol were administered if required, also to quantify the adequacy of analgesia, and adverse effects were evaluated. RESULTS: The results show that preemptive intraoperative analgesia with ketamine produces a good analgesia at the awakening, despite low duration (approximately 1 hour), and upgrades the analgesic effect of tramadol in the postoperative period. Among the adverse effects, some (for example nausea) were related to the administration of both analgesics and to the kind of surgery, others (hallucinosis, nystagmus, photophobia, psychomotor excitation, psychotic symptoms) were due to ketamine, and others (respiratory depression and hypotension) could be related to tramadol. Although the adverse effects due to ketamine are more numerous than those related to tramadol, the second could potentially be more dangerous. CONCLUSION: Our study suggests that preemptive low-doses ketamine is able to produce an adequate postoperative analgesia and increases the analgesic effect of tramadol; furthermore, ketamine adverse effects could be reduced by intraoperative administration of benzodiazepines and/or antiemetic drugs, or by the association of ketamine and a peripheral analgesic (ketorolac).     

Double Epidural Catheter with Ropivacaine versus Intravenous Morphine: A Comparison for Postoperative Analgesia after Scoliosis Correction Surgery

Background: Major spine surgery with a dorsal or ventrodorsal approach causes severe postoperative pain. The use of continuous epidural analgesia through one or two epidural catheters placed intraoperatively by the surgeon has been shown to provide efficient postoperative pain control. In this prospective unblinded study, the authors compared the efficacy of continuous intravenous morphine with a continuous double epidural catheter technique with ropivacaine after scoliosis correction.

Methods: Thirty patients with American Society of Anesthesiology physical status I-III were prospectively randomized to either the morphine group or the epidural group. At the end of surgery, patients in the epidural group received two epidural catheters placed by the surgeon, one directed cephalad and one caudally. Correct placement was checked radiographically. Postoperative analgesia until the first postoperative morning was performed with remifentanil target-control infusion for all patients. From that time remifentanil was stopped and continuous intravenous analgesia with morphine or double epidural analgesia with ropivacaine 0.3% was initiated (T0 = beginning of study). Pain at rest and pain in motion (using a visual analog scale from 0-100), the amount of rescue analgesics, sensory level, motor blockade, postoperative nausea and vomiting, and pruritus were assessed every 6 h and bowel function was assessed every 12 h until T72 (end of study). Two days later, patient satisfaction was assessed.

Results: Pain scores at rest were significantly decreased in the epidural group at all time points except at T12, T60, and T72. Pain scores in motion were significantly decreased in the epidural group at T24, T48, and T72. Bowel activity was significantly better in the epidural group at T24, T36, T48, and T60. Postoperative nausea and vomiting and pruritus occurred significantly less frequently in the epidural group. No complications related to the epidural catheter occurred.     

Review: effect of preventive analgesia on postoperative pain

Preventive analgesia (administration of a technique or analgesic drug with the aim of reducing postoperative pain, hyperalgesia and allodynia) has shown to be effective in experimental studies. However, the results in patients have been controversial. A review has been made of the clinical trials published during the last 5 years to test the efficacy of preventive analgesia on postoperative pain. A search was made of the published literature in Medline, with the terms "pre-emptive analgesia", "preventive analgesia" and "postoperative pain", selecting prospective, controlled, randomised and double blind studies that compared analgesic regimens before and after the incision or the same or very similar postoperative conditions. A total of 27 studies were found during the period 2005-2010 that complied with the inclusion criteria. Analgesia measurement variables were analysed, such as postoperative pain, time passed until the first rescue, and total analgesic requirements. Preventive analgesia was effective in 15 of the 27 studies, with pre-incisional epidural drug administration being the most effective (local anaesthetics with or without opioids, clonidine). The possible effectiveness of preventive analgesia in humans is still controversial, partly due to the wide heterogeneity in the inclusion criteria, types of patients, or the analgesia measurement parameters analysed by the studies. More studies are required with common criteria and objectives.     

Preemptive Analgesia by Intravenous Low-dose Ketamine and Epidural Morphine in Gastrectomy: A Randomized Double-blind Study

Background: Morphine and ketamine may prevent central sensitization during surgery and result in preemptive analgesia. The reliability of preemptive analgesia, however, is controversial.

Methods: Gastrectomy patients were given preemptive analgesia consisting of epidural morphine, intravenous low-dose ketamine, and combinations of these in a randomized, double-blind manner. Postsurgical pain intensity was rated by a visual analog scale, a categoric pain evaluation, and cumulative morphine consumption.

Results: Preemptive analgesia by epidural morphine and by intravenous low-dose ketamine were significantly effective but not definitive. With epidural morphine, a significant reduction in visual analog scale scores at rest was observed at 24 and 48 h, and morphine consumption was significantly lower at 6 and 12 h, compared with control values. With intravenous ketamine, visual analog scale scores at rest and morphine consumption were significantly lower at 6, 12, 24, and 48 h than those in control subjects. The combination of epidural morphine and intravenous ketamine provided definitive preemptive analgesia: Visual analog scale scores at rest and morphine consumption were significantly the lowest at 6, 12, 24, and 48 h, and the visual analog scale score during movement and the categoric pain score also were significantly the lowest among the groups.     

A double-blind comparison of epidural ketamine and diamorphine for postoperative analgesia

Twenty patients who had abdominal hysterectomy under general anaesthesia were randomly assigned to receive either epidural ketamine (30 mg), or epidural diamorphine (5 mg) peri-operatively and on first request for analgesia. Failure to obtain satisfactory analgesia with one of the agents was treated by epidural administration of the other. Pain was assessed by an independent observer, and by the patient using a visual analogue scale. The mean (SD) pain score on recovery from general anaesthesia, on a scale of 0-4, was 2.9 (1.2) for the ketamine group and 1.0 (1.0) for the diamorphine group (p less than 0.01). The mean (SD) time to first request for analgesia was 272 (206) and 72 (41) minutes in the diamorphine and ketamine groups respectively (p less than 0.01). All patients in the diamorphine group obtained adequate analgesia, but all patients in the ketamine group were changed to epidural diamorphine. Epidural ketamine does not appear to be a sufficiently effective alternative to epidural diamorphine for routine use in postoperative pain.     

Epidural analgesia compared with intravenous morphine patient-controlled analgesia: postoperative outcome measures after mastectomy with immediate TRAM flap breast reconstruction

BACKGROUND AND OBJECTIVES: Epidural analgesia has been shown to provide superior pain control compared with intravenous (IV) opioids after major surgical procedures. In this study, we compared the effect of epidural analgesia and IV morphine patient-controlled analgesia (PCA) on pain relief, duration of hospitalization, oral nutrition, ambulation, and side effects in patients undergoing a major surgical procedure (i.e., unilateral mastectomy with immediate transverse rectus abdominis musculocutaneous flap reconstruction). METHODS: Eighteen patients were prospectively randomized to receive either epidural analgesia or PCA during the postoperative period. The intensity of pain was assessed daily by a 100-mm visual analog scale. The total length of hospital stay, time to ambulation, and time to oral nutrition were recorded. RESULTS: The epidural group had significantly lower pain scores at 3 evaluation times through postoperative day number 4 (P < .05). The total length of hospitalization for the epidural group (median, 101 hours) was significantly less than the PCA group (median, 126 hours; P = .0498). The time to first ambulation, time to first bowel sounds, time to tolerating oral nutrition, incidence of nausea/vomiting or pruritus, and time to first flatus were not statistically different between the groups. CONCLUSIONS: These results show that epidural analgesia compared with PCA offered improved pain control after breast reconstruction with immediate transverse rectus abdominis musculocutaneous flap reconstruction. It also resulted in a 25-hour reduction in time of hospitalization.