Intravenous single-dose tramadol versus meperidine for pain relief in renal colic

BACKGROUND AND OBJECTIVE: Comparison of the effectiveness of tramadol with meperidine given intravenously to emergency patients with suspected renal colic. METHODS: A double-blind, randomized clinical trial was performed in the Emergency Department of a tertiary-care university hospital. Consecutive patients with suspected renal colic (n = 47) were randomized to receive intravenously an initial dose of tramadol 50 mg (n = 23) or meperidine 50 mg (n = 24). After 30 min, additional doses of meperidine 50 mg were given intravenously as a rescue medication in an open fashion. Pain relief was assessed using a 10 cm visual analogue scale, the primary outcomes being pain relief at 15 and 30 min after the analgesics. Secondary outcomes were the frequency of rescue meperidine use and the development of side-effects. RESULTS: Visual analogue scale pain scores after 15 and 30 min decreased in both tramadol and meperidine groups (P < 0.05). However, pain relief was better in the meperidine group at the 15 and 30 min evaluations (P < 0.05). Only 11 patients (48%), initially receiving meperidine, needed more meperidine compared with 16 patients (67%) initially receiving tramadol. Both drugs were well tolerated with no adverse effects occurring in either group. CONCLUSIONS: Meperidine 50 mg was superior to tramadol 50 mg for acute pain relief in patients with suspected renal colic when given intravenously. Because many patients in both groups received supplemental meperidine and the response to tramadol alone cannot be predicted, clinicians may want to choose higher doses of meperidine alone or other alternative combinations.     

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 fall-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 scope > 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). It is concluded that intrathecal 5% meperidine in a dose of 1 mg·kg^?1 is superior to 5% heavy lidocaine because of the prolonged postoperative analgesia. The commercial 5% solution of meperidine can be used, without addition, for this purpose.     

Pain relief after major abdominal surgery: a double-blind controlled comparison of sublingual buprenorphine, intramuscular buprenorphine, and intramuscular meperidine

In a double-blind randomized study of three groups of 18 patients scheduled for major abdominal surgery the efficacy and side effects of sublingual buprenorphine were tested and compared to intramuscular meperidine and buprenorphine. Single doses of either 75 mg of meperidine, 0.4 mg of sublingual buprenorphine, or 0.3 mg of intramuscular buprenorphine were used. Patients given buprenorphine as sublingual tablets were significantly more conscious in the immediate postoperative period (Glasgow Coma Scale) than when given buprenorphine or meperidine intramuscularly. Median pain intensity differences (PID) showed equal pain relief, whereas the summarized pain intensity differences (SPID) were significantly higher in the intramuscular buprenorphine group compared to the meperidine group. Three cases of respiratory acidosis in the meperidine group required IPPV treatment, and one case in the intramuscular buprenorphine group required treatment. Sedation and nausea were the most common side effects in all three groups. We conclude that sublingual buprenorphine is useful for relief of postoperative pain and exhibited administrative advantages, when the patients were able to cooperate.     

Neonatal electroencephalographic patterns as affected by maternal drugs administered during labor and delivery

Effects of drugs used during labor and delivery on spontaneous (resting) and evoked brain electrical activity were studied in 45 normal human newborns 48 hours after delivery. Mothers received either anesthesia (general plus local) alone (group 1), anesthesia plus meperidine (group 2), anesthesia plus meperidine and promethazine (group 3), or anesthesia plus meperidine and diazepam (group 4). Autoregressive spectral analyses and subsequent stepwise discriminant analyses showed no differences in spontaneous brain electrical activity in the infants related to the type of drugs given to the mother. However, when auditory stimuli were reduced in intensity from 80 dB to 63 dB, a significant effect was found in newborn brain electrical activity between the anesthetic-only drug pattern (group 1) and the drug patterns of anesthetics with meperidine (group 2) and anesthetics with meperidine plus diazepam (group 4). The data suggest that this effect diminishes in the presence of promethazine (group 3). Evoked responses to visual, tactile, and olfactory stimuli remained unaffected.     

Analgesic effects of preincisional administration of dextromethorphan and tenoxicam following laparoscopic cholecystectomy

BACKGROUND: Pre-incisional treatment with either N-methyl-D-aspartate (NMDA) receptor antagonists or non-steroidal anti-inflammatory drugs (NSAIDs) improves postoperative pain relief. This study examines the effect on postlaparoscopic cholecystectomy (LC) pain of a combination of dextromethorphan (DM), a NMDA-receptor antagonist, and tenoxicam, a NSAID, given preoperatively. METHODS: Eighty-eight ASA I or II patients scheduled for LC were entered into a randomized, double-blind study and randomly allocated to one of four groups. Controls received 20 mg (4 ml) of chlorpheniramine maleate (CPM) IM and 4 ml of normal saline (N/S) IV. Group DM received 40 mg of DM (containing 20 mg of CPM) IM and 4 ml of N/S IV. Group T were given CPM 20 mg IM, and tenoxicam 40 mg (4 ml) IV. Group DM + T were given DM 40 mg (containing 20 mg of CPM) IM, and tenoxicam 40 mg IV. All treatments were given 30 min before skin incision. Analgesic effects were evaluated by Visual Analog Scale (VAS) pain scores at rest and during coughing, at 1, 2, 4, 12, 24 and 48 h after surgery. The time to the first request for meperidine for pain relief, and total meperidine consumption, were recorded for 48 h after surgery. RESULTS: Compared to controls, patients given DM and DM + T first requested meperidine significantly later, had lower meperidine consumption, made fewer requests for meperidine, and had lower pain scores. There were significant differences between the DM + T and T groups at 2 and 4 h in both resting and incident VAS pain scores, the incidence of meperidine requests and the time to first meperidine injection. There were significant differences between groups DM and T at 1 h for resting pain and at 2 and 4 h for incident pain. Except for a significant difference in the incident pain score 1 h after surgery, there were no other differences in pain scores between the DM and DM + T groups. Neither synergistic nor antagonistic interaction was observed between DM and tenoxicam. CONCLUSIONS: The results suggest that pretreatment with DM, but not tenoxicam, provides significant pre-emptive analgesia for postoperative pain management in patients after LC surgery. Combining DM and tenoxicam also gives good pain relief.     

The addition of adrenaline to thoracic epidural meperidine does not improve analgesia following thoracotomy

PURPOSE: Patient-controlled epidural analgesia (PCEA) with meperidine provides effective analgesia following thoracotomy. Accumulation of normeperidine, a meperidine metabolite with neuroexcitatory effects, has led to recommendations to limit the use of meperidine postoperatively. The purpose of this study was to determine if the addition of adrenaline to PCEA meperidine decreased meperidine consumption, reduced serum normeperidine levels, and improved analgesia following thoracotomy. METHODS: Following Research Ethics approval consenting patients were randomly assigned to PCEA with either meperidine (2 mgxmL(-1)) + adrenaline (2 microgxmL(-1)) or meperidine alone (2 mgxmL(-1)). All patients received a standardized anesthetic and similar perioperative care. Visual analogue pain scores (at rest and with activity), quality of recovery (QoR) scores, and side effects were documented six, 24, and 48 hr postoperatively. Serum levels of meperidine and normeperidine were measured at the same time points. RESULTS: Forty-six patients completed the study protocol. Meperidine consumption (mean+/-SD) was similar in the meperidine + adrenaline and the meperidine groups (601+/-211 mg vs 580+/-211 mg over 48 hr, respectively; P=0.744). Serum meperidine levels were similar at all study time points. Serum normeperidine was not detected in any sample. Pain scores, QoR scores, and adverse events were comparable in both study groups. CONCLUSION: The addition of adrenaline did not influence PCEA meperidine consumption, analgesia outcomes, or QoR. Normeperidine did not accumulate in patients of either study group during the 48-hr study period. Meperidine for patient controlled epidural analgesia, with or without adrenaline, provides effective post-thoracotomy analgesia in selected patients.     

Labor analgesia and cesarean delivery: an individual patient meta-analysis of nulliparous women

BACKGROUND: The authors performed an individual patient meta-analysis of 2,703 nulliparous women who were randomized to either epidural analgesia or intravenous opioids for pain relief during labor from five trials conducted at their hospital. The primary purpose in this meta-analysis was to evaluate the effects of epidural analgesia during labor on the rate of cesarean delivery. METHODS: Between November 1, 1993, and November 3, 2000, 2,703 nulliparous women (2,188 healthy parturients and 515 women with pregnancy-induced hypertension) in spontaneous labor at term were randomized to receive either epidural analgesia or intravenous opioid analgesia in the five studies. Epidural analgesia was initiated with either epidural bupivacaine or intrathecal sufentanil and was maintained with a low-dose (0.0625% or 0.125%) mixture of bupivacaine with fentanyl. Intravenous opioid analgesia was initiated with 50 mg meperidine and 25 mg promethazine hydrochloride and was maintained with intravenous boluses of meperidine as needed. RESULTS: A total of 1,339 nulliparous women were randomized to receive epidural analgesia, and 1,364 women were randomized to receive intravenous meperidine analgesia. There was no difference in the rate of cesarean deliveries between the two analgesia groups (epidural analgesia, 10.5% [140 of 1,339] vs. intravenous meperidine analgesia, 10.3% [141 of 1,364]; adjusted odds ratio, 1.04; 95% confidence interval, 0.81-1.34; P = 0.920). Significantly more women randomized to epidural analgesia had forceps deliveries compared to meperidine analgesia (13% [172 of 1,339] vs. 7% [101 of 1,364]; adjusted odds ratio, 1.86; 95% confidence interval, 1.43-2.40; P < 0.001). Epidural women had longer first and second stages of labor. Women who received epidural analgesia reported lower pain scores during labor and delivery compared to women who received intravenous meperidine analgesia. CONCLUSION: Epidural analgesia compared to intravenous meperidine analgesia during labor does not increase the number of cesarean deliveries.     

Labor Analgesia and Cesarean Delivery: An Individual Patient Meta-analysis of Nulliparous Women

Background: The authors performed an individual patient meta-analysis of 2,703 nulliparous women who were randomized to either epidural analgesia or intravenous opioids for pain relief during labor from five trials conducted at their hospital. The primary purpose in this meta-analysis was to evaluate the effects of epidural analgesia during labor on the rate of cesarean delivery.

Methods: Between November 1, 1993, and November 3, 2000, 2,703 nulliparous women (2,188 healthy parturients and 515 women with pregnancy-induced hypertension) in spontaneous labor at term were randomized to receive either epidural analgesia or intravenous opioid analgesia in the five studies. Epidural analgesia was initiated with either epidural bupivacaine or intrathecal sufentanil and was maintained with a low-dose (0.0625% or 0.125%) mixture of bupivacaine with fentanyl. Intravenous opioid analgesia was initiated with 50 mg meperidine and 25 mg promethazine hydrochloride and was maintained with intravenous boluses of meperidine as needed.

Results: A total of 1,339 nulliparous women were randomized to receive epidural analgesia, and 1,364 women were randomized to receive intravenous meperidine analgesia. There was no difference in the rate of cesarean deliveries between the two analgesia groups (epidural analgesia, 10.5% [140 of 1,339]vs. intravenous meperidine analgesia, 10.3% [141 of 1,364]; adjusted odds ratio, 1.04; 95% confidence interval, 0.81-1.34; P = 0.920). Significantly more women randomized to epidural analgesia had forceps deliveries compared to meperidine analgesia (13% [172 of 1,339]vs. 7% [101 of 1,364]; adjusted odds ratio, 1.86; 95% confidence interval, 1.43-2.40; P < 0.001). Epidural women had longer first and second stages of labor. Women who received epidural analgesia reported lower pain scores during labor and delivery compared to women who received intravenous meperidine analgesia.     

Comparison of methotrimeprazine and meperidine as components of balanced anesthesia.

Methotrimeprazine (MTM) (0.5 mg/kg) and meperidine (1.5 mg/kg) was administered to four groups of 10 patients each. Two of these groups (I and II) received MTM or meperidine 12 minutes before, two other groups (III and IV), 3 minutes after, induction of thiopental anesthesia. N2O-O2 was administered after thiopental induction, and fractional doses of meperidine and muscle relaxants were used as required for maintenance of anesthesia. The preliminary administration of MTM or meperidine decreased the induction dose of thiopental by about 60 percent. When administered before thiopental, both had similar effects on heart rate, but whereas MTM moderately decreased, meperidine moderately increased systolic and diastolic blood pressure MTM had little or no effect on respiratory rate, which was significantly depressed by meperidine. When given after an induction dose of thiopental, the circulatory effects of MTM and meperidine were similar. Respiratory measurements were little affected by MTM but were markedly depressed by meperidine. The mug/kg/min maintenance doses of meperidine were about the same in the four groups. Postanesthetic recovery of consciousness was delayed in the two MTM groups. The incidence of postoperative nausea and vomiting was less in the MTM than in the meperidine groups. MTM appears to have several advantages over meperidine as a component of balanced anesthesia, but is not desirable if rapid postanesthetic recovery or early ambulation is important. Its use is indicated in patients in whom even transient respiratory depression is undesirable and in those in whom prolonged postoperative sedation is desired.     

A dose-range study of intrathecal meperidine combined with bupivacaine

Twenty-one patients were included in a randomized study to receive either 10 mg of 0.5% hyperbaric bupivacaine alone or combined with 0.05, 0.1, 0.2, 0.3, 0.4 or 0.5 mg.kg-1 meperidine for spinal anaesthesia. Sensory blockade was assessed by pin prick, motor blockade by the Bromage scale, and postoperative analgesia by VAS scores and by the time before the first demand for analgesia. Spinal meperidine did not change the duration of sensory blockade, but induced a dose-related increase in postoperative efficient analgesia. Spinal meperidine might be considered as a means to obtain postoperative analgesia in the hours immediately following surgery.     

Comparison of intrathecal meperidine and lidocaine in endoscopic urological procedures

The purpose of this study was to determine if a small dose of intrathecal meperidine would achieve adequate spinal anaesthesia while minimizing complications and to compare its effectiveness with lidocaine. The spinal anaesthetic effects of five per cent lidocaine 0.5 mg.kg-1 in 7.5 percent glucose (n = 20) or five per cent meperidine 0.5 mg.kg-1 (n = 22) were evaluated in 42 ASA physical status II or III patients. Intrathecal injection of the anaesthetic agent was given with the patient in the sitting position in which he remained for ten minutes before being placed in the lithotomy position. The onset time for sensory blockade was seven minutes in the lidocaine group and ten minutes in the meperidine group. Final sensory levels were identical in both groups. Mean arterial blood pressure decreased significantly in the lidocaine group but not in the meperidine group. Motor block was absent in ten patients in the meperidine group but was present in all the patients in the lidocaine group. Duration of postoperative analgesia was 968 min in the meperidine group and 681 min in the lidocaine group (NS). Complications such as nausea, vomiting, itching, drowsiness and respiratory depression were similar in the two groups. It is concluded that low-dose meperidine, 0.5 mg.kg-1, is effective as a spinal anaesthetic agent and has few complications.     

Comparison of morphine, meperidine, fentanyl, and sufentanil in balanced anesthesia: a double-blind study

A double-blind study comparing four narcotic analgesics of different potencies, meperidine, morphine, fentanyl, and sufentanil, was performed on consenting patients undergoing general or orthopedic surgery under balanced anesthesia. Blood pressure, measured through an indwelling arterial catheter, was recorded continuously, as were ECG and heart rates. The narcotics, made up in equipotent concentrations, were given as indicated by hemodynamic and clinical signs. Arterial blood samples were taken before and after induction, after intubation, before and after incision, at intervals during the operation, and postoperatively. Hemodynamic values and plasma levels of catecholamines during and after induction, intubation, incision, and throughout the operation were least in patients given sufentanil and greatest in those who received morphine or meperidine. Heart rates increased significantly after induction with meperidine and were significantly higher after intubation in morphine-treated and meperidine-treated patients than they were in patients receiving sufentanil. Intraoperatively, mean arterial blood pressure, rate-pressure product, and plasma norepinephrine levels were lowest in patients receiving sufentanil. Intraoperative plasma epinephrine levels were lowest in patients receiving sufentanil and meperidine. Because of increases in blood pressure, heart rate, or both to greater than 15% above control values, supplementation with a potent inhalational agent was necessary in 38%, 30%, and 29% of the patients given meperidine, morphine, and fentanyl, respectively. No sufentanil patient required supplementation. Side effects, including histamine release accompanied by tachycardia and hypotension, were most frequent and most severe in patients who received meperidine. After extubation, marked increases in heart rate, blood pressure, and plasma norepinephrine and epinephrine occurred in some patients in each group. The incidence of postoperative respiratory depression was greatest in patients given morphine (mean dose of naloxone 8.6 micrograms/kg) and least with sufentanil (mean dose of naloxone 1.8 micrograms/kg) and fentanyl (3.2 micrograms/kg naloxone).     

Common bile duct pressure changes after fentanyl, morphine, meperidine, butorphanol, and naloxone

Five groups of 10 patients received thiamylal, enflurane, nitrous oxide-oxygen anesthesia for elective cholecystectomy. The common bile duct was intubated via the cystic duct with a 16-g plastic catheter, and the control intraductal pressure was measured. Patients then were given equi-analgesic doses of fentanyl, morphine, meperidine, butorphanol, or placebo intravenously, and the common bile duct pressure was recorded for 20 min. Fentanyl, morphine, and meperidine significantly increased pressure in the common duct (P less than 0.001). Butorphanol produced only insignificant changes. Naloxone given 20 min later significantly (P less than 0.001) decreased pressure in patients given fentanyl, morphine, and meperidine. Naloxone given without narcotics caused an increase in pressure that, although statistically significant (P less than 0.03), was clinically insignificant. In five additional patients anesthetized with thiamylal, nitrous oxide-oxygen and intermittent doses of fentanyl, common bile duct pressures were normal.     

A dose-response study of intravenous regional anesthesia with meperidine

Intravenous regional anesthesia (IVRA) with meperidine in doses > or = 100 mg provides effective postoperative analgesia. However, this technique is associated with excessive opioid-related side effects, which limit its clinical usefulness. The minimal dose of meperidine that is effective for IVRA has yet to be established. We added 0, 10, 20, 30, 40, or 50 mg of meperidine to 0.5% lidocaine IVRA for either carpal tunnel or tenolysis surgery. Pain and sedation scores and the incidence of side effects were assessed in the postanesthesia care unit. The duration of analgesia, defined as the time to first request for pain medications, and use of acetaminophen/codeine (T3) tablets were measured. The duration of analgesia increased, in a dose-dependent manner, in the groups that received 0, 10, 20, and 30 mg of meperidine. There was no significant difference in the duration of analgesia for patients receiving > or = 30 mg of meperidine. T3 use was similar in the groups that received 0, 10, and 20 mg of meperidine and in the groups that received 30, 40, and 50 mg. T3 use was significantly lower in the larger dose groups. The incidence of sedation and of all other side effects was significantly higher in the groups that received 30-50 mg of meperidine compared with those that received smaller doses. We conclude that doses of meperidine large enough to produce the most effective postoperative analgesia with IVRA lidocaine causes a significant incidence of side effects, thus limiting its clinical usefulness. Implications: Meperidine may be a useful addition to 0.5% lidocaine for i.v. regional anesthesia. We showed that 30 mg is the optimal dose of meperidine with respect to postoperative analgesia. However, this dose caused a significant incidence of sedation, dizziness, and postoperative nausea and vomiting.     

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

Purpose

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

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 bupivacaïne or 3 ml of heavy bupivacaïne 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 bupivacaïne 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 bupivacaïne has no intra-operative advantage over heavy bupivacaïne 0.5%.     

Double-blind comparison of the neurobehaviour of neonates following the administration of different doses of meperidine to the mother.

The Early Neonatal Neurobehavioural Scale (E.N.N.S.) tests, first described by Scanlon, et al.1 were administered to 920 neonates on the first and second days of life. Meperidine was not given to 389 mothers, 50 mg was given to 358 mothers and 75 to 150 mg to 173 mothers within four hours of delivery. The delivery was conducted under chloroprocaine epidural anaesthesia in 280, ketamine-nitrous oxide general anaesthesia in 180, thiopentone-nitrous oxide general anaesthesia in 180 and lidocaine pudendal block in 280. All babies were over 2500 grams in weight with an Apgar score of at least 8 at one minute and 10 at five minutes. All were delivered from healthy women 18 to 35 years of age following a normal labour. The evaluator was unaware of the anaesthetic management, the method of delivery or the perinatal risk factors. There was no significant difference between the mothers and babies in the three meperidine dosage groups for maternal parity, maternal age, birth weight, number of forceps deliveries or duration of labour. Administration of meperidine was associated with a broad spectrum depression of most items on the E.N.N.S. on both the first and second days of life. The depression was greatest with the highest dose of meperidine. The depression produced by anaesthetic agents and meperidine were additive and the highest scores on this scale were obtained in those babies delivered under chloroprocaine epidural anaesthesia without meperidine.     

Clinical and pharmacokinetic aspects of the combination of meperidine and prilocaine for spinal anaesthesia

The aim of this study was to determine whether the addition of a small dose of prilocaine could augment the spinal block induced by meperidine and affect intrathecal meperidine pharmacokinetic behaviour. Spinal anaesthesia was performed in 60 men scheduled for endoscopic resection of a prostatic adenoma or bladder tumour under spinal anaesthesia. They were allocated randomly to receive either 1 mg.kg-1 meperidine (Group 1, n = 30), or 1 mg.kg-1 meperidine plus 0.5 mg.kg-1 prilocaine (Group 2, n = 30). Blood samples were collected prior to and for 24 hr after spinal injection in 24 patients (12 in each group). Plasma meperidine levels were assayed by gas chromatography. Complete motor block was achieved in all Group 2 patients, but was incomplete in seven of Group 1 (P less than 0.05). The onset of both motor and sensory blocks was shorter (P less than 0.01) in Group 2 and the duration was longer (P less than 0.05). Coadministration of prilocaine modifies meperidine pharmacokinetic behaviour. The area under curve was 48% greater (P less than 0.01) and Cmax was higher in Group 2 than in Group 1, 145.8 +/- 42.2 vs 107 +/- 20.5 ng.ml-1 (P less than 0.001). No evidence of respiratory depression was noted in any of the patients. Despite the increase in plasma meperidine concentrations, no side effects were observed. The plasma concentrations remained at one third to one sixth the levels reported to induce a respiratory depression. It is concluded that the addition of prilocaine to meperidine improves motor and sensory block during surgery and alters meperidine kinetics without producing major side effects.     

Effects of repeated doses of benzodiazepines on arterial blood gases and transcutaneous Po2

The effects of repeated doses of benzodiazepines, diazepam and midazolam in combination with meperidine on arterial blood gases and transcutaneous PO2 were studied in eight healthy volunteers. The study was designed to mimic a clinical situation. Initially two doses of either midazolam 0.05 mg/kg or diazepam in fat emulsion 0.15 mg/kg were given in a randomized crossover fashion with a 20-min interval, followed by meperidine 0.5 mg/kg another 20 min later. The opioid effects were then antagonized by naloxone 0.4 mg. The initial doses of benzodiazepines caused an increase in PaCO2 and a decrease in PaO2. The changes in PaO2 were of short duration and recovered to baseline levels between injections. However, they came sooner and were more pronounced after midazolam. The changes in PtcO2 paralleled those in PaO2. The PtcO2 index as a measure of cardiac output and peripheral blood flow adequacy was increased immediately after the first injection of midazolam but was otherwise not different from control. There were no differences between the drugs concerning PtcO2 index. PaCO2 increased after the first benzodiazepine injection and remained so throughout the study. Addition of meperidine caused only small changes in PaO2 and PaCO2. These changes were reversed by naloxone. In spite of different elimination kinetics there was no difference in the duration of respiratory depression between the two benzodiazepines.     

Efficacy of tramadol versus meperidine for pain relief and safe recovery after adenotonsillectomy

BACKGROUND AND OBJECTIVE: Adequate relief of pain after tonsillectomy is a common problem. We compared meperidine and tramadol when given at induction of anaesthesia with respect to their effects on postoperative pain relief and emergence characteristics after adenotonsillectomy in children. METHODS: Fifty children aged 4-7 yr undergoing tonsillectomy were randomly assigned to receive either tramadol 1 mg kg(-1) (n = 25) or meperidine 1 mg kg(-1) (n = 25) before commencement of the surgical procedure. Anaesthesia was induced with propofol (with cis-atracurium for muscle relaxation) and maintained with sevoflurane in oxygen and nitrous oxide. Postoperative pain was scored by a blinded observer using a facial pain scale in the recovery room at 0 (at arrival of the patient in the postoperative care unit) and at 10, 20 and 45 min thereafter. Agitation scores were also assessed by the same observer at 0 min. Heart rate and mean arterial pressure were recorded at regular intervals. The time to recovery to spontaneous respiration and the incidence of postoperative nausea and vomiting were noted. RESULTS: Facial pain scale scores were increased in the tramadol group at 0, 10 and 20 min (P < 0.05). No difference was observed in scores at the 45th min postoperation. Agitation scores were higher in the tramadol group than in the meperidine group. No statistical difference was found between the two groups. Heart rates and mean arterial pressures were similar in both groups. The time to recovery to spontaneous respiration was delayed with meperidine compared with tramadol (P < 0.05). The incidence of nausea and vomiting was not statistically different between groups. CONCLUSIONS: Meperidine was more effective for pain relief and provides better emergence characteristics than tramadol after tonsillectomy in children.     

Anesthetic techniques and postoperative emesis in pediatric strabismus surgery

BACKGROUND AND OBJECTIVES: Postoperative emesis after pediatric strabismus surgery continues to be a problem, despite the use of antiemetics. The purpose of this study was to identify an anesthetic technique associated with the lowest incidence of vomiting after pediatric strabismus surgery. METHODS: A prospective, randomized, double-blind study was conducted to evaluate the effect of intravenous fentanyl, meperidine, or peribulbar block with propofol infusion on emesis in 105 pediatric patients undergoing strabismus surgery. Anesthesia was maintained with nitrous oxide, oxygen, and propofol infusion. Ketorolac 1.0 mg/kg -1 intramuscular was administered to all patients after induction. Patients were given either a peribulbar block, intravenous fentanyl 2 microg/kg -1 , or intravenous meperidine 1mg/kg -1 for perioperative analgesia. The emesis scores were observed for the first 24 hours postoperatively. RESULTS: The incidence of emesis was significantly lower (1 of 35; 2.9%) in the peribulbar group compared with the meperidine group (9 of 35; 25.6%) (P <.01) in the first 24 hours. The fentanyl group had a higher incidence of postoperative vomiting (4 of 35; 11.4%) than did the peribulbar group; the difference, however, was not statistically significant. CONCLUSION: Among the three techniques, peribulbar block with propofol-based anesthesia is the technique with the lowest incidence of postoperative emesis. Fentanyl-propofol is an equally acceptable alternative; however, meperidine-propofol is associated with a high incidence of postoperative emesis.