Comparison of intrathecal meperidine and lidocaine in endoscopic urological procedures

Preventing shivering with adjuvant low dose intrathecal meperidine: A meta-analysis of randomized controlled trials with trial sequential analysis

The aim of this systematic review and meta-analysis is to evaluate the pros and cons of adjuvant low dose intrathecal meperidine for spinal anaesthesia. We searched electronic databases for randomized controlled trials using trial sequential analysis (TSA) to evaluate the incidence of reduced rescue analgesics, shivering, pruritus, nausea and vomiting when applying adjuvant intrathecal meperidine. Twenty-eight trials with 2216 patients were included. Adjuvant intrathecal meperidine, 0.05-0.5 mg kg-1, significantly reduced incidence of shivering (relative risk, RR, 0.31, 95% confidence interval, CI, 0.24 to 0.40; TSA-adjusted RR, 0.32, 95% CI, 0.25 to 0.41). Intrathecal meperidine also effectively reduced need for intraoperative rescue analgesics (RR, 0.27, 95% CI, 0.12 to 0.64; TSA-adjusted RR, 0.27, 95% CI, 0.08 to 0.91) and the incidence of pruritus was unaffected (RR, 2.31, 95% CI, 0.94 to 5.70; TSA-adjusted RR, 1.42, 95% CI, 0.87 to 2.34). However, nausea and vomiting increased (RR, 1.84, 95% CI, 1.29 to 2.64; TSA-adjusted RR, 1.72, 95% CI, 1.33 to 2.23; RR, 2.23, 95% CI, 1.23 to 4.02; TSA-adjusted RR,1.96, 95% CI, 1.20 to 3.21). Under TSA, these results provided a sufficient level of evidence. In conclusion, adjuvant low dose intrathecal meperidine effectively attenuates spinal anaesthesia-associated shivering and reduces rescue analgesics with residual concerns for the nausea and vomiting.

Effect of low dose of intrathecal pethidine on the incidence and intensity of shivering during cesarean section under spinal anesthesia: a randomized, placebo-controlled, double-blind clinical trial

Introduction

Shivering is among the unpleasant and potentially harmful side effects of spinal anesthesia. The aim of this randomized double-blind clinical trial was to compare the antishivering effect of two different doses of intrathecal pethidine on the incidence and intensity of shivering and other side effects in patients who underwent cesarean section.

Methods

In this study, 150 parturient females scheduled for nonemergent cesarean section were randomly allocated to three groups. Spinal anesthesia was performed with 0.5% hyperbaric bupivacaine (12.5 mg), plus 0.5 mL of 0.9% saline in the standard group (S group), and the same dose of bupivacaine with 5 mg (P5 group) or 10 mg of pethidine (P10 group). Demographic and surgical data, incidence and intensity of shivering (primary outcome), hemodynamic indices, forehead and core temperatures, maximum sensory level, Apgar scores, and adverse events were evaluated by a blinded observer.

Results

There were no significant differences between the three study groups regarding the demographic and surgical data, hemodynamic indices, core temperatures, and maximum sensory level (P>0.05). The incidence and intensity of shivering were significantly less in the P5 and P10 groups (P<0.001) when compared with the S group. There were no significant differences between groups for secondary outcomes, except pruritus, which was more common in the P5 and P10 groups when compared with the S group (P=0.01).

Conclusion

Low dose of intrathecal pethidine is safe, and can decrease the incidence and intensity of shivering during cesarean section, without having major side effects.

Efficacy of dexmedetomidine on postoperative shivering: a meta-analysis of clinical trials

PURPOSE

Shivering is a frequent complication in the postoperative period. The aim of the current meta-analysis was to assess the efficacy of dexmedetomidine on postoperative shivering.

METHODS

Two researchers independently searched PubMed, EMBASE and the Cochrane Central Register of Controlled Trials for controlled clinical trials. The meta-analysis was performed by Review Manager.

RESULTS

Thirty-nine trials with 2,478 patients were included in this meta-analysis. Dexmedetomidine reduced postoperative shivering compared with placebo (risk ratio [RR] = 0.26; 95% confidence interval [CI]: 0.20 to 0.34), with a minimum effective dose of 0.5 µg·kg(-1) (RR = 0.36; 95% CI: 0.21 to 0.60). The anti-shivering effect can be achieved both intravenously and epidurally when administered within two hours prior to the end of surgery. The efficacy of dexmedetomidine was similar to widely used anti-shivering agents, such as fentanyl, meperidine, tramadol, clonidine and so on; however, dexmedetomidine may increase the incidence of sedation, hypotension, bradycardia and dry mouth.

CONCLUSIONS

The present meta-analysis indicates that dexmedetomidine shows superiority over placebo, but not over other anti-shivering agents. Therefore, considering its high price and potential adverse events, dexmedetomidine may not be appropriate solely for the purpose of the prevention of postoperative shivering.

The effects of different doses of intrathecal meperidine on the incidence and severity of shivering during lower extremity orthopedic surgery under spinal anesthesia: A randomized, placebo-controlled, double blind-clinical trial

BACKGROUND

Shivering associated with spinal anesthesia is a common complication. It also causes more usage of oxygen, increased production of carbon dioxide (CO2), and lactic acidosis with movement of clots and bleeding after surgery. This study was performed to compare the different dosages of intrathecal meperidine and their effects on shivering during and after surgery and to compare these to the control group.

MATERIALS AND METHODS

This study is a clinical trial. Target population consisted of the patients who were candidates for lower limb orthopedic surgery under spinal anesthesia. About 120 patients were chosen and randomly divided into four groups. In group 1, spinal anesthesia was performed with 3 ml marcaine 0.5% and 0.1 mg/kg meperidine. In group 2, 3 ml marcaine 0.5% and 0.2 mg/kg meperidine was given. In group 3, 3 ml marcaine 0.5% and 0.3 mg/kg meperidine, and in the fourth group, 3 ml marcaine 0.5% and normal saline in the same volume were injected. During surgery and recovery, hemodynamic index and shivering were recorded.

RESULTS

Based on the analyzed data, in the fourth group 23 patients (76.7%) had shivering. While the prevalence of shivering in the first, second, and third groups was 15 patients (50%), 11 patients (36.7%), and 3 patients (10%), respectively. Chi-square test showed significant difference in the four groups (P < 0.001).

CONCLUSIONS

Using higher dosage of intrathecal meperidine (0.3 mg/kg) was more effective than using lower dosage of meperidine (0.1 mg/kg and 0.2 mg/kg) in reducing the incidence and severity of shivering during spinal anesthesia in lower extremity orthopedic surgeries.

Prophylactic effects of intrathecal Meperidine and intravenous Ondansetron on shivering in patients undergoing lower extremity orthopedic surgery under spinal anesthesia

Objective:

Intraoperative hypothermia is a common problem with anesthesia. Spinal anesthesia, the same as general anesthesia, affects the process of temperature regulation. The aim of this study was to compare the prophylactic effect of intravenous (IV) ondansetron with intrathecal (IT) meperidine on prevention of shivering during spinal anesthesia in patients underwent orthopedic surgery of the lower limb.

Methods:

In this study, 120 patients with American Society of Anesthesiologists physical status I to II, between the ages 16 and 65 were randomized into three groups. Group O and Group M were given IV ondansetron 8 mg and IT meperidine 0.2 mg/kg, before spinal anesthesia, respectively. Group C received IV saline 0.9%. The core and ambient temperatures, the incidence and intensity of shivering, blood pressure, heart rate, and maximum level of sensory block were recorded.

Findings:

Shivering was observed in 15%, 2.5%, and 37.5% of patients in Groups O, M, and C, respectively. There was a significant difference between Group O and M compared to Group C (P = 0.023 for Group O vs. Group C, P < 0.001 for Group M vs. Group C, P = 0.049 for Group M vs. Group O). Shivering incidence and intensity in Group M was significantly lower than Group O (P = 0.049 and P = 0.047, respectively). Twenty-two patients required additional IV meperidine among which 15 patients were from Group C (37.5%), six patients from Group O (15%) and one patient from Group M (2.5%).

Conclusion:

We concluded that IT meperidine and IV ondansetron comparably can decrease intensity and incidence of shivering compared to control group as well as decreasing the requirement to additional doses of meperidine for shivering the control without any hemodynamic side effect.

Dexmedetomidine for the prevention of shivering during spinal anesthesia

PURPOSE

The aim of this study was to evaluate the effect of dexmedetomidine on shivering during spinal anesthesia.

METHODS

Sixty patients (American Society of Anesthesiologists physical status I or II, aged 18-50 years), scheduled for elective minor surgical operations under spinal anesthesia with hyperbaric bupivacaine, were enrolled. They were administered saline (group C, n = 30) or dexmedetomidine (group D, n = 30). Motor block was assessed using a Modified Bromage Scale. The presence of shivering was assessed by a blinded observer after the completion of subarachnoid drug injection.

RESULTS

Hypothermia was observed in 21 patients (70%) in group D and in 20 patients (66.7%) in group C (p = 0.781). Three patients (10%) in group D and 17 patients (56.7%) in group C experienced shivering (p = 0.001). The intensity of shivering was lower in group D than in group C (p = 0.001). Time from baseline to onset of shivering was 10 (5-15) min in group D and 15 (5-45) min in group C (p = 0.207).

CONCLUSION

Dexmedetomidine infusion in the perioperative period significantly reduced shivering associated with spinal anesthesia during minor surgical procedures without any major adverse effect during the perioperative period. Therefore, we conclude that dexmedetomidine infusion is an effective drug for preventing shivering and providing sedation in patients during spinal anesthesia.

Anesthetic efficacy of lidocaine/meperidine for inferior alveolar nerve blocks

The authors, using a crossover design, randomly administered, in a single-blind manner, inferior alveolar nerve blocks using 36 mg of lidocaine with 18 microg of epinephrine or a combination of 36 mg of lidocaine with 18 microg epinephrine plus 36 mg meperidine with 18 microg of epinephrine, at 2 separate appointments, to 52 subjects. An electric pulp tester was used to test for anesthesia, in 4-minute cycles for 60 minutes, of the molars, premolars, and central and lateral incisors. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes and the 80 reading was continuously sustained for 60 minutes. Using the lidocaine solution, successful pulpal anesthesia ranged from 8 to 58% from the central incisor to the second molar. Using the lidocaine/meperidine solution, successful pulpal anesthesia ranged from 0 to 17%. There was a significant difference (P < .05) between the lidocaine and lidocaine/meperidine solutions for the lateral incisors through the second molars. We conclude that the addition of meperidine to a standard lidocaine solution does not increase the success of the inferior alveolar nerve block.

Anesthetic Efficacy of Lidocaine/Meperidine for Inferior Alveolar Nerve Blocks in Patients with Irreversible Pulpitis

The purpose of this prospective, randomized, single-blind study was to compare the anesthetic efficacy of lidocaine with epinephrine to lidocaine plus meperidine with epinephrine for inferior alveolar nerve blocks (IAN) in patients with mandibular posterior teeth experiencing irreversible pulpitis. Forty-eight emergency patients diagnosed with irreversible pulpitis of a mandibular posterior tooth randomly received, in a single-blind manner, 36 mg of lidocaine with 18 mug epinephrine or 36 mg of lidocaine with 18 mug of epinephrine plus 36 mg meperidine with 18 mug epinephrine, using a conventional inferior alveolar nerve block. Endodontic access was begun 15 minutes after solution deposition, and all patients were required to have profound lip numbness. Success was defined as no or mild pain (visual analog scale recordings) upon endodontic access or initial instrumentation. The success rate for the inferior alveolar nerve block using the lidocaine solution was 26%, and for the lidocaine/meperidine solution, the success rate was 12%. There was no significant difference (p = 0.28) between the two solutions. In conclusion, for mandibular posterior teeth with irreversible pulpitis, the addition of 36 mg of meperidine to a lidocaine solution administered in a conventional IAN block did not improve the success rate over a standard lidocaine solution.

Continuous Intrathecal Meperidine for Severe Refractory Cancer Pain

The control of severe cancer pain may be problematic despite advances in pain management. Patients with severe intractable pain and/or intractable side effects may require aggressive interventional pain management strategies including the administration of medications by the continuous intrathecal route and/or neurosurgical procedures. Various medications, including opioids, local anesthetics, and alpha-2 agonists may be used intrathecally for the control of cancer pain. Failure of the intrathecal route may require the additional use of neurosurgical procedures such as cordotomy for pain control. We describe a case of severe cancer pain refractory to conventional intrathecal medications and cordotomy that was successfully managed by the addition of meperidine to the intrathecal regimen.

Intrathecal meperidine decreases shivering during cesarean delivery under spinal anesthesia

Shivering associated with spinal anesthesia is uncomfortable and may interfere with monitoring. We performed this prospective, double-blinded, and randomized study to determine whether intrathecal meperidine (0.2 mg/kg) decreases the incidence and intensity of shivering after spinal anesthesia for cesarean delivery. Forty parturients scheduled for nonemergent cesarean delivery were enrolled in two groups. Spinal anesthesia consisted of hyperbaric bupivacaine (0.75%; 10.5 mg), morphine 0.15 mg, and, in the experimental group, meperidine (0.2 mg/kg) or, in the control group, normal saline. Data collection, including sensory block level, blood pressure, core temperature, and shivering intensity, was performed every minute for 10 min, every 3 min for 33 min, and then every 5 min until the sensory level receded to L4. Time to highest sensory level, maximum number of blocked segments, sensory and motor blockade regression, and systolic blood pressure showed no difference between groups. The incidence of shivering was less (P < 0.02) in the meperidine group, as was its intensity (P < 0.003). Intrathecal meperidine (0.2 mg/kg) is effective in reducing the incidence and intensity of shivering associated with spinal anesthesia for cesarean delivery.

IMPLICATIONS

Previous studies have suggested that IV meperidine is helpful for treating intraoperative shivering. This study was undertaken to evaluate spinal meperidine and found that it decreases the incidence and intensity of shivering associated with spinal anesthesia for cesarean delivery.

Implantable devices for pain control: spinal cord stimulation and intrathecal therapies

Untreated chronic pain is costly to society and to the individual suffering from it. The treatment of chronic pain, a multidimensional disease, should rely on the expertise of varying health care providers and should focus not only on the neurobiological mechanisms of the process but also on the psychosocial aspects of the disease. Implantable devices are costly and invasive, and such efficacious therapies should be used only when more conservative and less costly therapies have failed to provide relief of pain and suffering. Spinal cord stimulation provides neuromodulation of neuropathic, but not nociceptive, pain signals and when used for appropriate indications in the right individuals provides approximately 60-80% long-term pain relief in 60-80% of patients trialled for efficacy. Intrathecal therapies with opioids such as morphine, fentanyl, sufentanil or meperidine--or non-opioids such as clonidine or bupivacaine--provide analgesia in patients with nociceptive or neuropathic pain syndromes. Baclofen, intrathecally, provides profound relief of muscle spasticity due to multiple sclerosis, spinal cord injuries, brain injuries or cerebral palsy.

The effects of three graded doses of meperidine for spinal anesthesia in African men

The intrathecal injection of 0.7-1 mg/kg meperidine provides spinal anesthesia of only short duration. In this study, we investigated the effects of three different doses of meperidine for spinal anesthesia on the duration and level of sensory block and the incidence of side effects. Forty-five African men were randomly allocated to receive one of three doses of intrathecal meperidine: Group A = 1.2 mg/kg, Group B = 1.5 mg/kg, and Group C = 1.8 mg/kg. The duration of sensory block was significantly longer after 1.5 mg/kg compared with 1.2 mg/kg meperidine (112 +/- 19 vs 79 +/- 27 min; P = 0.001). Increasing the dose to 1.8 mg/kg did not further increase the duration of block. The level and the onset of the block were not affected by the dose. Common side effects were fatigue (27%), pruritus (20%), and nausea (7%). Seven patients had respiratory depression and seven had a decrease of systolic arterial blood pressure (SAP) >30% from baseline. There was no difference in the incidence of any side effect among groups. Respiratory depression and decreases in SAP were observed 5-50 min after meperidine injection. Twenty-two patients had no pain after the sensory block had terminated. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects.

IMPLICATIONS

Intrathecal meperidine 1 mg/kg provides surgical anesthesia for only 40-90 min. We investigated the effects of three larger doses of meperidine in 45 African men. The 1.5 and 1.8 mg/kg doses provide a longer duration of anesthesia compared with 1.2 mg/kg. Nausea, pruritus, and respiratory depression were common in all dose groups. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects.

Sameridine is safe and effective for spinal anesthesia: a comparative dose-ranging study with lidocaine for inguinal hernia repair

Sameridine is a new compound with local anesthetic and analgesic properties when injected intrathecally. We studied the anesthetic and analgesic efficacy of three doses of isobaric sameridine (15, 20, and 23 mg) compared with 100 mg of hyperbaric lidocaine for spinal anesthesia in 140 healthy male patients undergoing inguinal hernia repair. Patients received spinal anesthesia with 4 mL of the study drug injected at the L2-3 or L3-4 interspace in the lateral decubitus position. All three doses of sameridine provided spinal anesthesia similar to lidocaine, with a slightly longer time to reach peak block height. The failure rate was highest in the 15-mg sameridine group, and accrual was discontinued in that group after 35 patients. The duration of blockade was shorter with lidocaine, but the time to voiding and ambulation was similar in all groups. Patients receiving sameridine were less likely to request morphine for postoperative analgesia and were less likely to request any analgesia in the first 4 h after injection of the drug. Use of oral analgesics (hydrocodone and acetaminophen) was similar in all groups after the first 4 h of the 24-h observation. We conclude that, in the three doses studied, sameridine provided spinal anesthesia similar to lidocaine, but with residual analgesia after drug injection that reduced the need for systemic analgesics in the first 4 h postoperatively.

IMPLICATIONS

In this clinical trial, we show the potential efficacy of a class of drugs that can produce both spinal anesthesia and postoperative analgesia when used for hernia repair.

Intrathecal pethidine: pharmacology and clinical applications

Pethidine is the only member of the opioid family that has clinically important local anaesthetic activity in the dose range normally used for analgesia. Pethidine is unique as the only opioid in current use that is effective as the sole agent for spinal anaesthesia. In lower doses, intrathecal pethidine is also an effective analgesic for treating pain in labour. This paper reviews the pharmacology of intrathecal pethidine and clinical experience reported to date. Articles reviewed include those identified by a Medline search using keywords "intrathecal" or "spinal anaesthesia/ anesthesia" and "pethidine" or "meperidine". Reference lists from identified papers were scrutinized to identify further relevant articles.

Intrathecal pethidine: an alternative anaesthetic for transurethral resection of prostate?

We aimed to determine the usefulness of intrathecal pethidine as the sole anaesthetic for transurethral resection of prostate (TURP) while comparing the incidence of hypotension with intrathecal bupivacaine. A double-binded randomized prospective trial was conducted involving 40 patients for TURP. The patients were divided equally into two groups; group A received 2 ml 0.5% bupivacaine intrathecally and group B received 40 mg pethidine intrathecally. Changes in blood pressure and heart rate were measured over the first 30 minutes. The highest sensory block and the time to reach it were documented. The degree of motor blockade was also recorded. There was no significant difference in the incidence of hypotension. The pethidine group had significantly greater reduction in heart rate, a lower degree of motor block, shorter period before requests for postoperative analgesia but a higher incidence of sedation, nausea and vomiting. Intrathecal pethidine did not offer any advantage over intrathecal bupivacaine for TURP.

Bupivacaine decreases epidural meperidine requirements after abdominal surgery

PURPOSE

The purpose of this study was to determine the optimal of three concentrations of bupivacaine (0.0%, 0.05%, 0.10%) to add to an epidural infusion of meperidine (1 mg.ml-1) for postoperative pain relief.

METHODS

In this prospective, double blind study, 60 patients undergoing abdominal surgery with general anaesthesia were randomized into three groups to receive for postoperative epidural analgesia: 1) 1 mg.ml-1 meperidine (0% group), 2) bupivacaine 0.05% and 1 mg.ml-1 meperidine (0.05% group), 3) bupivacaine 0.10% and 1 mg.ml-1 meperidine (0.10% group). Postoperatively, the epidural infusion rate was titrated to produce adequate analgesia and pain was assessed at rest and on movement.

RESULTS

There were no differences in demographic data, average pain scores or side effects among the three groups. However, there was improvement of pain relief at rest over time in the three groups (P < 0.05). Postoperative epidural analgesic infusion rates increased over time for the three groups (P < 0.05) and were lower in the 0.10% group (mean of 10.0 ml.hr-1) than in the 0% group (mean of 12.6 ml.hr-1) (P < 0.05). More than half of the 0% group had serum meperidine concentrations > 400 g.L-1 to control moderate postoperative pain.

CONCLUSION

Although analgesia was identical among groups, the lower serum concentrations of meperidine support the addition of bupivacaine 0.10% to meperidine when administered as a continuous infusion following abdominal surgery.

Modification of pain on injection of propofol. A comparison of pethidine and lignocaine

One hundred and fifty ASA 1 and 2 patients were randomly allocated to receive pethidine 25 mg (1 ml), lignocaine 10 mg (1 ml) or 0.9% saline (1 ml) on a double-blind basis, as pretreatment to reduce pain on injection of propofol. Both active treatments were significantly better than placebo at preventing pain (p < 0.01). Lignocaine was most effective in preventing pain in men (p < 0.05) whilst pethidine was more effective in women (p < 0.05).

A comparison of the haemodynamic effects of intrathecal meperidine, meperidine-bupivacaine mixture and hyperbaric bupivacaine

PURPOSE

To study the haemodynamic effects of intrathecal meperidine, administered either alone or mixed with bupivacaine.

METHODS

We studied 42 Chinese patients, aged 59-87 yr, scheduled for transurethral bladder or prostate surgery, randomized into three equals groups, that received either meperidine 0.8 mg.kg-1, meperidine 0.4 mg.kg-1 plus 1.5 ml of 0.5% heavy bupivacaine or 3 ml of heavy bupivacaine 0.5%. Non-invasive systolic (SAP) and mean (MAP) arterial pressures, central venous pressure and cardiac index, stroke index and heart rate (HR) measured by the BoMed NCCOM3-R7S bioimpedance device, were recorded over the first 25 min. Systemic vascular resistance index (SVRI) was derived. Onset of sensory and motor block was also measured. Decreases in MAP of 25% were treated with colloid and metaraminol.

RESULTS

The onset of block was slower in the meperidine group (P < 0.05). Decreases in SAP, MAP and SVRI (all; P < 0.001) occurred within five minutes in all three groups. The HR was increased in the bupivacaine group (P = 0.03), but bradycardias treated with atropine occurred in six patients receiving meperidine and four patients receiving the mixture. Six patients receiving meperidine and two patients receiving the mixture required general anaesthesia for inadequate block. The incidence of nausea and vomiting was higher in the patients receiving meperidine (P < 0.05). No other complications were encountered.

CONCLUSIONS

Intrathecal meperidine used alone or mixed with bupivacaine has no intra-operative advantage over heavy bupivacaine 0.5%.

Anaesthesia and adverse effects after intrathecal pethidine hydrochloride for urological surgery

Anaesthesia, postoperative analgesia and the incidence of adverse effects after intrathecal pethidine hydrochloride 0.50 mg.kg-1 and 0.75 mg.kg-1 were assessed and compared with a conventional technique using isobaric bupivacaine 13.75 mg in patients undergoing transurethral resection of the prostate gland. Sensory and motor block were significantly shorter with both pethidine regimens than with bupivacaine (p < 0.001). Although sensory and motor block were shorter after pethidine 0.50 mg.kg-1 than after pethidine 0.75 mg.kg-1 the difference in duration was clinically insignificant. The incidence of incomplete motor block was significantly greater with pethidine 0.50 mg.kg-1 than with bupivacaine 13.75 mg.kg-1 (p < 0.01). Visual analogue pain scores recorded after the operation were low and were similar in the pethidine groups to those obtained with bupivacaine alone. Mean arterial blood pressure was significantly lower in both pethidine groups compared with the bupivacaine group between 30 and 240 min after intrathecal injection (p < 0.001). However, the within-group reductions in blood pressure were within clinically acceptable limits. The incidences of nausea and emesis were low and emesis occurred in patients in the bupivacaine group only (p < 0.03). Pruritus was seen only in patients receiving pethidine. Intra-operative sedation occurred more often in patients receiving both pethidine 0.50 mg.kg-1 and 0.75 mg.kg-1 compared with patients receiving bupivacaine (p < 0.04). Both pethidine regimens provided acceptable anaesthesia and there were no significant differences between the two regimens in quality of intra-operative anaesthesia, incidence of adverse events or postoperative analgesia.

Intravenous regional anesthesia with meperidine

Forty-five ASA physical status I volunteers, divided in three groups of 15 each, received intravenous regional anesthesia (IVRA) of the upper limb with 40 mL meperidine 0.25%, lidocaine 0.5%, or 0.9% sodium chloride (isolated ischemia) by random allocation. Using a double-blind method, the onset and recovery of sensory block was tested at six sites of the forearm and hand. The onset of complete motor block was also assessed. The symptoms after deflation of the tourniquet were recorded. The onset of block, as determined by pin-prick touch, and cold was significantly faster in the meperidine group (P < 0.001) than in the saline group, but also slower (P < 0.001) than in the lidocaine group. After the tourniquet was deflated, recovery occurred in reverse order. A complete motor block was noted in all volunteers from the meperidine and lidocaine groups, but in only 11 cases from the 0.9% sodium chloride group (P < 0.01). In the meperidine group, motor block developed concomitantly or prior to sensory block. There was a significant increase in the incidence of dizziness, nausea, and pain at the injection site in the meperidine group in comparison with the lidocaine group. We conclude that meperidine has local anesthetic action on the peripheral nerve in vivo, but that its single use for IVRA should be a second choice for patients allergic to local anesthetics.

An investigation of the local anaesthetic effects of pethidine in volunteers

We have investigated the local anaesthetic effects of 0.1% and 0.2% pethidine compared with 0.5% prilocaine using an intravenous regional anaesthetic technique, in a randomised, double-blind study in volunteers. Both pethidine and prilocaine produced a sensory and motor blockade, although the latter had a more profound effect, with a faster onset and slower recovery. Pethidine in low concentration clearly has a local anaesthetic action on peripheral nerves.

Intrathecal meperidine for elective caesarean section: a comparison with lidocaine

The purpose of this study was to determine the efficacy of intrathecal meperidine in patients undergoing Caesarean section, and also to compare meperidine with heavy lidocaine. Fifty full-term pregnant women, ASA physical status I or II, presenting for elective Caesarean section under spinal anaesthesia were randomly divided into two groups with 25 in each, to receive either intrathecal meperidine or lidocaine. All patients received premedication with oral ranitidine, 150 mg, the night before surgery, and again two hours before surgery. Patients in the meperidine group were also given metoclopramide iv 10 mg one hour before surgery. After iv 20 ml.kg-1 Ringer's lactate, patients were given either 5% meperidine 1 mg.kg-1 or 5% heavy lidocaine 1.2 to 1.4 ml intrathecally. The sensory and motor blockades in all except two patients in each group who required sedation at the time of skin incision were adequate for surgery. None of the mothers suffered from any major side effects. The incidence of hypotension was higher in the lidocaine group than in meperidine group (P < 0.05). Pruritus and drowsiness were more common in meperidine group than in lidocaine group (P < 0.01). All the newborns in both groups cried immediately after birth and had an Apgar score > 7. The mean duration of postoperative analgesia was six hours in the meperidine group and one hour in the lidocaine group (P < 0.01). Postoperative analgesia requirement was less in the meperidine than in the lidocaine group (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)