Michael G. F. Rorarius

Gabapentin for the prevention of postoperative pain after vaginal hysterectomy

&NA; Gabapentin alleviates and/or prevents acute nociceptive and inflammatory pain both in animals and volunteers, especially when given before trauma. Gabapentin might also reduce postoperative pain. To test the hypothesis that gabapentin reduces the postoperative need for additional pain treatment (postoperative opioid sparing effect of gabapentin in humans), we gave 1200 mg of gabapentin or 15 mg of oxazepam (active placebo) 2.5 h prior to induction of anaesthesia to patients undergoing elective vaginal hysterectomy in an active placebo‐controlled, double blind, randomised study. Gabapentin reduced the need for additional postoperative pain treatment (PCA boluses of 50 &mgr;g of fentanyl) by 40% during the first 20 postoperative hours. During the first 2 postoperative hours pain scores at rest and worst pain score (VAS 0–100 mm) were significantly higher in the active placebo group compared to the gabapentin‐treated patients. Additionally, pretreatment with gabapentin reduced the degree of postoperative nausea and incidence of vomiting/retching possibly either due to the diminished need for postoperative pain treatment with opioids or because of an anti‐emetic effect of gabapentin itself. No preoperative differences between the two groups were encountered with respect to the side effects of the premedication. However, 15 mg oxazepam was more effective in relieving preoperative anxiety than 1200 mg gabapentin.

Persistent pain following knee arthroplasty.

Background and objective The prevalence of persistent pain after orthopaedic surgery has been the subject of only few studies and the risk factors for persistent pain have been evaluated even more rarely. The purpose of the present study was to evaluate the degree and the risk factors of persistent pain after knee arthroplasty. Methods The prevalence of persistent postoperative pain after knee replacement was evaluated with a questionnaire in a large, register-based cross-sectional prevalence study. The main hypothesis was that the type of operation (primary, bilateral, revision) would influence the prevalence of persistent postoperative pain. Logistic regression analysis was performed to test the hypothesis and to find other possible risk factors for the development of persistent pain. Results The total number of patients was 855. The operation was a primary arthroplasty in 648 patients (75.7%), a bilateral arthroplasty in 137 patients (21.1%) and a revision arthroplasty in 70 patients (8.2%). The response rate was 65.7%. The type of operation was not associated with the prevalence of persistent pain, but the degree of early postoperative pain was the strongest risk factor. If the degree of pain during the first postoperative week was from moderate to intolerable, the risk for the development of persistent pain was three to 10 times higher compared with patients complaining of mild pain during the same period. Other risk factors were the long duration of preoperative pain and female sex. Conclusion Intensity of early postoperative pain and delayed surgery increase the risk of the persistent pain after knee arthroplasty.

The total peroxyl radical-trapping ability of plasma and cerebrospinal fluid in normal and preeclamptic parturients.

Plasma and cerebrospinal fluid total peroxyl radical-trapping antioxidative parameter (TRAP) and the main antioxidant components of TRAP (vitamin E, ascorbic acid, uric acid, protein sulfhydryl groups, and the unidentified antioxidant proportion) were analyzed in 11 preeclamptic parturients, 9 healthy parturients with an uncomplicated pregnancy, and 10 healthy nonpregnant women. In addition, the possible effects of ongoing labor were studied in 10 healthy parturients. The samples of plasma and cerebrospinal fluid (CSF) were collected at cesarean section (pregnant women) or minor surgical procedure (nonpregnant women). Normal pregnancy or ongoing labor induced no significant changes in total TRAP, as compared with nonpregnant women, but significant changes in the percentage contributions of individual antioxidants were noted in plasma and CSF. In preeclampsia, a significant increase in TRAP was noted in both plasma and CSF. This increase was mainly due to an increased proportion of uric acid and unidentified antioxidants in plasma samples, and an increased proportion of unidentified antioxidants in CSF. The concentration of CSF ascorbic acid was decreased in preeclampsia, and a negative correlation between CSF ascorbic acid and blood pressure was observed.

Etoricoxib pre-medication for post-operative pain after laparoscopic cholecystectomy.

Background:  Etoricoxib alleviates and prevents acute pain. The hypothesis of our study was that the pre‐operative use of etoricoxib would reduce the post‐operative need for additional pain treatment.

Lack of analgesic effect of parecoxib following laparoscopic cholecystectomy

Background:  The cyclo‐oxygenase‐2 inhibitor, parecoxib, can be administered parenterally. The recommended dose for post‐operative use is 40 mg twice daily, which may not be the appropriate dose for the treatment of visceral pain. We studied the effect of a single dose of parecoxib of either 40 or 80 mg in laparoscopic cholecystectomy, and its effect on opioid‐induced side‐effects.

Neurologic sequelae after caesarean section

Background: Because pregnancy increases the sensitivity of nervous tissue to local anaesthetics, pregnant patients may be at higher risk of developing neurologic deficits after spinal block than non‐pregnant patients. Therefore, we evaluated prospectively the incidence and type of neurologic symptoms after spinal anaesthesia with hyperbaric bupivacaine for caesarean section.

Peripherally administered sufentanil inhibits pain perception after postpartum tubal ligation.

The clinical effectiveness of locally administered opioids is still under discussion; in particular, the potency of morphine in settings other than intra-articular arthroscopy has been questioned. We developed another pain model, postpartum resection of the fallopian tubes for sterilisation, in which each patient serves as her own control when one side is infiltrated with the active drug (in this study sufentanil 5 mg) and the contralateral side with normal saline. In the control group both sides are infiltrated with plain saline. After 30 min from the end of anaesthesia onwards, 26 out of 30 patients observed significant pain relief on the side of the sufentanil infiltration, which in 11 patients lasted until the end of the observation period 24 h postoperatively; no difference was observed in the control group. In our pain model with a high assay sensitivity, the infiltration of one side with the lipophilic test drug, sufentanil, caused local analgesia in primarily non-inflamed tissue. The use of each patient as her own control excluded inter-subject bias.

Effect of intravenous diclofenac or indomethacin on the emergence from anaesthesia for tonsillectomy.

We evaluated the effects of a single dose of diclofenac (75 mg) or indomethacin (50 mg) on intraoperative events and on the early recovery phase. The study was performed in a randomised, double‐blind, placebo‐controlled fashion in 63 adult patients scheduled for elective tonsillectomy. Study infusions started intravenously immediately after the induction of general anaesthesia with thiopentone; maintenance was with N2O/O2 and halothane. After intubation with the aid of suxamethonium, the patients breathed spontaneously via a Bain coaxial system. Perioperative events (bleeding tendency, bleeding, need for pain medication, physical recovery) were recorded with the aid of a questionnaire applied to the anaesthesia nurses and estimation of vigilance, attention, concentration, short‐term memory, and simple motor speed during recovery was with the aid of three neuropsychological tests (thumb tapping test, digit span test and homogenic interference test). No significant differences between the three groups were found in systolic and diastolic arterial pressures, the results of the questionnaire, and those of the neuropsychological tests. The ability to keep the head elevated for at least 5 s recovered significantly later (P < 0.05) and heart rate levels in the indomethacin group were significantly lower (P < 0.001) than in the other two groups. No enhanced bleeding during the perioperative period was observed. Diclofenac and indomethacin in the doses used in our study have only a marginal effect on the patients emergence from anaesthesia.

Efficacy and safety of premedication with oral ketamine for day-case adenoidectomy compared with rectal diazepam/diclofenac and EMLA®

Background: Because of its pain‐attenuating and sedative properties oral ketamine has been used as premedication in children and adults. We wanted to compare in children scheduled for adenoidectomy safety and efficacy of oral ketamine with a premedication that causes similar preoperative sedation and relief of pain at the venepuncture site. We also evaluated the effect of i.v. glycopyrrolate added to these combinations.

Does abstinence from smoking or a transdermal nicotine system influence atracurium-induced neuromuscular block?

The purpose of the present study was to investigate the interaction of chronic smoking and the actions of atracurium (ATR).Twenty nonsmokers (NON-SMOK) were compared with 80 smokers, who were randomized into three groups: 30 patients received 21 mg/d transdermal nicotine system >or=to10 h before fentanyl/thiopental/N2 O/O2/isoflurane anesthesia (TD-NICO), whereas the abstinent group received a placebo transdermal system (ABST, n = 30). The TD-NICO and ABST groups refrained from smoking for at least 10 h before the induction of anesthesia. A third group was allowed to smoke until 1-3 h before anesthesia (SMOK, n = 20). Neuromuscular block was monitored using a Relaxograph[trade mark sign] (Datex, Helsinki, Finland). The electromyographic response was recorded from the first dorsal interosseus muscle of the hand. The inspiratory isoflurane concentration was kept constant at 0.7 vol% in all patients. After an initial bolus dose of 0.5 mg/kg ATR, no significant difference was observed among the groups regarding onset time and maximal neuromuscular block. In Group ABST, the duration of block until 25% recovery of T1 was 48.2 +/- 10.1 min, which was significantly longer (analysis of variance post hoc tests) than in Groups TD-NICO, SMOK, and NON-SMOK (42.7 +/- 7.1, 41.4 +/- 10.4, and 42.8 +/- 7.3 min, respectively). The maintenance dose of ATR in Group ABST (0.23 +/- 0.03 mg [center dot] kg-1 [center dot] h (-1)) was smaller than in Groups TD-NICO, SMOK, and NON-SMOK (0.30 +/- 0.07, 0.32 +/- 0.06, and 0.32 +/- 0.05 mg [center dot] kg-1 [center dot] h-1, respectively). We conclude that abstinence from smoking increases the duration of ATR-induced neuromuscular block and reduces the maintenance dose of ATR in smokers. Perioperative use of a transdermal nicotine system prevents these abstinence-induced changes in duration and maintenance-dose. Implications: The purpose of the present study was to investigate the interaction of chronic smoking and atracurium. Smokers who refrain from smoking for >10 h require a smaller maintenance dose of atracurium than nonsmokers. However, using a transdermal nicotine system prevents the decrease in maintenance dose during abstinence. (Anesth Analg 1998;87:430-3)