Antiemetic and analgesic-sparing effects of diphenhydramine added to morphine intravenous patient-controlled analgesia

Background. This study was designed to examine the analgesicand dose-related antiemetic efficacy of diphenhydramine–morphinemixture for intravenous patient-controlled analgesia (PCA). Methods. Healthy women, undergoing abdominal total hysterectomywere recruited to this double-blinded randomized placebo-controlledstudy. Patients were randomly allocated to one of three groups(n=40 each). In group 1, patients received saline at inductionand morphine 1 mg ml^–1 alone for postoperative PCA. Patientsin groups 2 and 3 received diphenhydramine 30 mg i.v. at inductionand were given a 1.2:1 or a 4.8:1 ratio, respectively, of diphenhydramine–morphinemixture for postoperative PCA. Results. A total of 112 patients completed the study. The incidenceof postoperative nausea (31.6% vs 67.6%, P<0.01) and vomiting(15.8% vs 40.5%, <0.05) was significantly lower in group3 than in group 1. Furthermore, the incidence of severe nauseawas significantly lower in group 3 than in group1 (2.6% vs 24.3%,P<0.05). The rescue antiemetic requirements were also significantlyless in group 3 than in group 1 (5.3% vs 24.3%, P<0.05).However, there was no significant difference between group 2and group 1 in any of the comparisons. Pain intensity, 24-hmorphine consumption and diphenhydramine-related side-effects,such as sedation or dry mouth, did not differ among the threegroups. Conclusion. An initial bolus of diphenhydramine 30 mg at anaestheticinduction followed by postoperative PCA with a 4.8:1, but not1.2:1, diphenhydramine–morphine mixture provides an effectiveantiemetic efficacy without morphine-sparing effects.     

Effect of intraoperative intravenous crystalloid infusion on postoperative nausea and vomiting after gynaecological laparoscopy: comparison of 30 and 10 ml kg(-1)

Background. I.V. fluid administration has been shown to reducepostoperative nausea and vomiting (PONV). The optimum dose isunknown. We tested the hypothesis that administration of i.v.crystalloid of 30 ml kg^–1 would reduce the incidence ofPONV compared with 10 ml kg^–1 of the same fluid. Methods. A total of 141 ASA I female patients undergoing electivegynaecological laparoscopy were randomized, in double-blindfashion, to receive either 10 ml kg^–1 (n=71; CSL-10 group)or 30 ml kg^–1 (n=70; CSL-30 group) of i.v. compound sodiumlactate (CSL). Results. In the first 48 h after anaesthesia, the incidenceof vomiting was lower in the CSL-30 group than in the CSL-10group (8.6% vs 25.7%, P=0.01). Anti-emetic use was less in theCSL-30 group at 0.5 h (2.9% vs 14.3%, P=0.04). The incidenceof severe nausea was significantly reduced in the treatmentgroup at awakening (2.9% vs 15.7%, P=0.02), 2 h (0.0% vs 8.6%,P=0.04) and cumulatively (5.7% vs 27.1%, P=0.001). The numbersneeded to treat to prevent vomiting, severe nausea and antiemeticuse in the first 48 h were 6, 5 and 6, respectively. Conclusion. I.V. administration of CSL 30 ml kg^–1 to healthywomen undergoing day-case gynaecological laparoscopy reducedthe incidence of vomiting, nausea and anti-emetic use when comparedwith CSL 10 ml kg^–1.     

Dextromethorphan and intrathecal morphine for analgesia after Caesarean section under spinal anaesthesia

Background. Dextromethorphan is an N-methyl-D-aspartic acidantagonist which can attenuate acute pain with few side-effects.In this prospective, randomized, double-blind study of dextromethorphanand intrathecal morphine, we investigated postoperative pain,pruritus, nausea and vomiting in women undergoing Caesareansection under spinal anaesthesia. Methods. Women were allocated randomly to one of six groups,to receive intrathecal morphine 0.05, 0.1 or 0.2 mg plusoral dextromethorphan 60 mg or placebo. Results. The addition of dextromethorphan did not reduce postoperativepain scores (P=0.83). Compared with women receiving intrathecalmorphine 0.05 mg, women receiving higher doses had a significantlyhigher incidence of nausea and vomiting [odds ratio for intrathecalmorphine 0.1 mg, 4.0 (95% confidence interval 1.2–14.1);for intrathecal morphine 0.2 mg, 7.9 (2.3–27.1)].Compared with women receiving intrathecal morphine 0.05 mg,women receiving higher doses also had a significantly higherincidence of pruritus [odds ratio for intrathecal morphine 0.1 mg,3.2 (95% confidence interval 1.3–8.2); for intrathecalmorphine 0.2 mg, 3.7 (1.4–9.5)]. Women receivingdextromethorphan had a lower incidence of nausea and vomiting[odds ratio 2.6 (1.1–6.3)]. Conclusions. Postoperative pain after Caesarean section underspinal anaesthesia was not reduced by the addition of oral dextromethorphanto a multimodal approach including intrathecal morphine. Br J Anaesth 2003; 90: 653–8     

Prevention of postoperative nausea and vomiting after spinal morphine for Caesarean section: comparison of cyclizine,dexamethasone and placebo

Background. Low-dose intrathecal (spinal) morphine (0.1–0.2mg) for Caesarean section delivers excellent postoperative analgesiabut is associated with significant nausea and vomiting. We comparedthe antiemetic efficacy of cyclizine, dexamethasone, and placeboin this clinical setting. Methods. Ninety-nine women undergoing elective Caesarean sectionunder spinal anaesthesia were allocated randomly, in a double-blindstudy design, to receive either cyclizine 50 mg, dexamethasone8 mg, or placebo as a single-dose infusion in saline 0.9%, 100ml on completion of surgery. Spinal anaesthesia consisted of:hyperbaric bupivacaine 0.5%, 2.0 ml; fentanyl 10 µg; andspinal morphine 0.2 mg. The primary outcome measure was theincidence of nausea. Results. The incidence of nausea was significantly less in patientsreceiving cyclizine compared with dexamethasone and placebo(33 vs 60 and 67%, respectively, P<0.05). Severity of nauseaand number of vomiting episodes were also less at 3–6h in cyclizine patients. Overall satisfaction with postoperativecare at 24 h, expressed on a 100 mm visual analogue scale, wasgreater in cyclizine [78 (28)] than either dexamethasone [58(31), P=0.03] or placebo [51 (28), P=0.008]. Conclusion. We conclude that following spinal morphine 0.2 mgand fentanyl 10 µg analgesia for Caesarean section, cyclizine50 mg i.v. reduces the incidence of nausea compared with dexamethasone8 mg i.v. or placebo. It also lessens the severity of nauseaand vomiting, and increases maternal satisfaction in the earlypostoperative period. Br J Anaesth 2003; 90: 665–70     

Dolasetron prophylaxis reduces nausea and postanaesthesia recovery time after remifentanil infusion during monitored anaesthesia care for extracorporeal shock wave lithotripsy

Background. Remifentanil is used as an analgesic for differentprocedures performed during monitored anaesthesia care. Opioid-inducednausea and vomiting can be troublesome. Methods. This prospective, randomized, double-blind study wasperformed to evaluate the efficacy of prophylaxis with dolasetronin reducing the frequency of postoperative nausea and durationof discharge time. Forty urological patients, undergoing electiveambulatory extracorporeal shock wave lithotripsy (ESWL) receivedrandomly either dolasetron 12.5 mg i.v. (Group 1) or placebo(Group 2) 10 min before a patient-adapted continuous infusionof remifentanil 0.15–0.4 µg kg^–1 min^–1was administered. Frequency and intensity (VAS 0–100 mm)of nausea, retching, and vomiting were assessed by patientsand blinded investigators during and after the procedure. Results. Patient characteristics, baseline values, durationof ESWL, and total dose of remifentanil did not differ betweengroups. The frequency (Group 1/Group 2; 20/55%; P<0.05) andmean (SD) maximal intensity [15 (9)/45 (14) mm; P<0.05] ofnausea during 24 h was significantly reduced after dolasetronand discharge times in Group 1 were less than Group 2[22 (14)/45 (28) min; P<0.05]. Br J Anaesth 2003; 90: 194–8     

Intrathecal morphine and clonidine for coronary artery bypass grafting

Background. After cardiac surgery adequate postoperative analgesiais necessary. We assessed analgesia using intrathecal morphineand clonidine. Methods. In a double-blind randomized study, 45 patients havingcoronary artery bypass graft surgery were allocated randomlyto receive i.v. patient-controlled analgesia (PCA) morphine(bolus, 1 mg; lock-out interval, 7 min) (control group), eitheralone or combined with intrathecal morphine 4 µg kg^–1or with both intrathecal morphine 4 µg kg^–1and clonidine 1 µg kg^–1. Intrathecal injectionswere performed before the induction of general anaesthesia.Pain was measured after surgery using a visual analogue scale(VAS). We recorded i.v. PCA morphine consumption during the24 h after operation. Results. Morphine dosage [median (25th–75th percentiles)]was less in the first 24 h in the patients who were given intrathecalmorphine + clonidine [7 (0–37) mg] than in other patients[40.5 (15–61.5) mg in the intrathecal morphine group and37 (30.5–51) mg in the i.v. morphine group]. VAS scoreswere lower after intrathecal morphine + clonidine compared withthe control group. Time to extubation was less after intrathecalmorphine + clonidine compared with the i.v. morphine group [225(195–330) vs 330 (300–360) min, P<0.05]. Conclusion. Intrathecal morphine and clonidine provide effectiveanalgesia after coronary artery bypass graft surgery and allowearlier extubation. Br J Anaesth 2003; 90: 300–3     

Effects of acetaminophen on morphine side-effects and consumption after major surgery: meta-analysis of randomized controlled trials

Background. Acetaminophen is commonly used for the managementof perioperative pain. However, there is a marked discrepancybetween the extent to which acetaminophen is used and the availableevidence for an analgesic effect after major surgery. The aimof this systematic review is to determine the morphine-sparingeffect of acetaminophen combined with patient-controlled analgesia(PCA) with morphine and to evaluate its effects on opioid-relatedadverse effects. Methods. MEDLINE and the Cochrane Library were searched to selectrandomized controlled trials which compared PCA morphine alonewith PCA morphine plus acetaminophen administered orally orintravenously. Studies were evaluated for their quality basedon the Oxford Quality Scale. Outcome measures were morphineconsumption over the first 24 h after surgery, patient satisfactionand the incidence of morphine side-effects, including nauseaand vomiting, sedation, urinary retention, pruritus and/or respiratorydepression. Results. Seven prospective randomized controlled trials, including265 patients in the group with PCA morphine plus acetaminophenand 226 patients in the group with PCA morphine alone, wereselected. Acetaminophen administration was not associated witha decrease in the incidence of morphine-related adverse effectsor an increase in patient satisfaction. Adding acetaminophento PCA was associated with a morphine-sparing effect of 20%(mean, –9 mg; CI –15 to –3 mg; P=0.003) overthe first postoperative 24 h. Conclusion. Acetaminophen combined with PCA morphine induceda significant morphine-sparing effect but did not change theincidence of morphine-related adverse effects in the postoperativeperiod.      

Influence of peroperative opioid on postoperative pain after major abdominal surgery: sufentanil TCI versus remifentanil TCI. A randomized, controlled study

Background. Sufentanil and remifentanil are characterized bytwo different pharmacokinetic profiles. The aim of this studywas to compare the effects of sufentanil and remifentanil administeredusing target-controlled infusion (TCI) on recovery and postoperativeanalgesia after major abdominal surgery. Methods. Thirty adult patients scheduled for open colorectalsurgery were included in a prospective, randomized study. SufentanilTCI (sufentanil group) or remifentanil TCI (remifentanil group)was administered during surgery. In the remifentanil group,30 min before the anticipated end of surgery, morphine 0.15mg kg^–1 was administered i.v. In the sufentanil group,an effect-site concentration of 0.25 ng ml^–1 wastargeted at extubation. In both groups, postoperative pain wascontrolled by titration of i.v. morphine and then patient-controlledanalgesia with morphine. Results. The extubation time was similar in the two groups (mean(SD) 13 (6) and 14 (6) min in the sufentanil and remifentanilgroups respectively). Visual analogue scale scores were significantlygreater during the first 2 h after tracheal extubation in theremifentanil group than in the sufentanil group. The time tofirst analgesic request in the postanaesthesia care unit wassignificantly longer in the sufentanil group than in the remifentanilgroup (55 (64) (range 2–240) vs 11 (7) (1–29) min;P<0.001). The cumulative morphine dose for titration wassignificantly greater in the remifentanil group (P<0.01).The cumulative morphine dose used during titration and patient-controlledanalgesia was significantly greater in the remifentanil group4, 12 and 24 h after extubation (P<0.05). Conclusion. TCI sufentanil (0.25 ng ml^–1 effect-siteconcentration at extubation) is more effective than the intraoperativecombination of remifentanil TCI infusion with morphine bolus(0.15 mg kg^–1) for postoperative pain relief aftermajor abdominal surgery and does not compromise extubation andrecovery. Br J Anaesth 2003; 91: 842–9     

Role of beta-blockade in anaesthesia and postoperative pain management after hysterectomy

Background. Perioperative use of ß-blockers has beenadvocated as a strategy to prevent cardiac sequelae. This studyevaluated the influence of perioperative esmolol administrationupon anaesthesia and postoperative pain management amongst patientsundergoing hysterectomy. Methods. Ninety-seven ASA I–II patients, undergoing abdominaltotal hysterectomy, were randomly divided into one of two groups.Patients in the Esmolol group received an i.v. loading doseof esmolol 0.5 mg kg^–1 followed by infusion of 0.05 mgkg^–1 min^–1 before anaesthesia induction. The infusionwas documented at the completion of surgery. The Control groupreceived a volume of normal saline. After surgery, all patientswere treated with patient-controlled i.v. analgesia (PCA), whichwas programmed to deliver 1 mg of morphine on demand for 3 consecutivedays. Pain intensity on movement and at rest, sedation score,and side effects were recorded. Results. The two groups were comparable with respect to theircharacteristics. Patients in the esmolol group received significantlylower end-tidal isoflurane concentrations (1.0 (0.3) vs 1.4(0.5)%, respectively; P<0.001) and fentanyl (0.9 (0.2) vs1.2 (0.5) µg kg^–1, respectively; P=0.006) duringanaesthesia. They also showed a reduced heart rate and arterialpressure response to tracheal intubation, skin incision, andtracheal extubation. The Esmolol group consumed less PCA morphinein 3 days (37.3 (8.4) vs 54.7 (11.2) mg, respectively; P=0.005).Pain intensity and medication side effects were similar in thetwo groups. Conclusion. The results suggest that perioperative esmolol administrationduring anaesthesia reduces the intraoperative use of inhalationanaesthetic and fentanyl, decreases haemodynamic responses,and reduced morphine consumption for the first 3 postoperativedays.     

Epidural versus intrathecal morphine for postoperative analgesia after Caesarean section

Background. Perispinal anaesthesia for Caesarean section allowsinjection of epidural (ED) or intrathecal (i.t.) morphine toprovide long-lasting postoperative analgesia. To compare thesetwo routes, a prospective, randomized, double-blinded studyof 53 patients undergoing elective Caesarean section was performed. Methods. Combined spinal-epidural anaesthesia with 6 mg of i.t.hyperbaric bupivacaine plus sufentanil 5 µg, and additionalED lidocaine was used. Additionally, each patient received either2 mg (2 ml) of ED morphine plus 1 ml of i.t. normal saline (EDgroup, n=28), or 0.075 mg (1 ml) of i.t. morphine plus 2 mlof ED normal saline (i.t. group, n=25). Additional postoperativeanalgesia was given in the form of propacetamol and ketoprofen,plus self-administered i.v. morphine. Results. No major respiratory depression occurred. Time to firstdemand of morphine was similar in the ED (307.5 min) and i.t.(310 min) groups, as was the incidence of side-effects suchas sedation, pruritis, nausea, and vomiting. During the first24 postoperative hours, VAS pain scores were greater in thei.t. group (P=0.032), as was additional morphine consumption(4 vs 1.5 mg) (P=0.03). Conclusions. The ED protocol was more effective than the i.t.protocol, whilst side-effects were similar. Br J Anaesth 2003; 91: 690–4     

Effect of epidural bupivacaine vs combined epidural bupivacaine and morphine on gastrointestinal function and pain after major gynaecological surgery

In a double-blind study, we investigated the effects of postoperativeepidural local anaesthetic, with or without addition of epiduralmorphine, on postoperative pain and gastrointestinal functionin patients scheduled for radical hysterectomy and pelvic lymphadenectomy.Forty patients were randomized into two study groups: 48-h postoperativeepidural 0.2% bupivacaine 8 ml h^–1 (bupi group)or 48-h postoperative epidural 0.2% bupivacaine/morphine 50µg at 4 ml h^–1 (bupi/morph group). Patients wereobserved for at least 96 h after surgery. No differencesin pain at rest, during cough or mobilization were observed.Patients in the bupi group requested a significant greater amountof supplementary analgesics, but times to first flatus and defaecationwere reduced compared with patients in the bupi/morph group.Itching was a significant problem in patients in the bupi/morphgroup. No differences in postoperative nausea and vomiting,mobilization or time to discharge from hospital were observedbetween groups. The addition of morphine to postoperative epiduralbupivacaine has only limited effect on pain relief and increasestime to normalization of gastrointestinal function. Br J Anaesth 2001; 87: 727–32     

Pre-emptive analgesic efficacy of tramadol compared with morphine after major abdominal surgery

Background. Studies of pre-emptive analgesia in humans haveshown conflicting results. This prospective, randomized, double-blind,controlled study was designed to test the hypothesis that areduction in postoperative morphine consumption can be achievedby tramadol administered after induction of anaesthesia. Methods. Ninety patients were allocated randomly to receivei.v. tramadol (1 mg kg^–1) (Group T), morphine(0.1 mg kg^–1) (Group M) or saline 2 ml(Group S) after induction of anaesthesia. At peritoneal closure,a standardized (0.1 mg kg^–1) morphine loadingdose was given to all patients for postoperative pain management.Patients were allowed to use a patient-controlled analgesia(PCA) device giving bolus doses of morphine 0.025 mg kg^–1.Discomfort, sedation, pain scores, cumulative morphine consumption,and side-effects were recorded at 1, 2, 6, 12 and 24 hafter the start of PCA. Results. There were no significant differences between groupsin mean pain, discomfort, and sedation scores at any study period.Cumulative morphine consumption was significantly lower in GroupM at 12 and 24 h after starting the PCA than in Group S.In Group T, it was lower only after 24 h (28% less in GroupM and 17% less in Group T; P<0.017). There were no significantdifferences in morphine consumption between Groups T and M. Conclusions. Tramadol (1 mg kg^–1), administeredafter induction of anaesthesia, offered equivalent postoperativepain relief, and similar recovery times and postoperative PCAmorphine consumption compared with giving morphine 0.1 mg kg^–1.These results also suggest that presurgical exposure to systemicopioid analgesia may not result in clinically significant benefits Br J Anaesth 2003; 91: 209–13     

Prophylactic ondansetron does not improve patient satisfaction in women using PCA after Caesarean section

Eighty-one consenting women undergoing elective Caesarean sectionunder spinal anaesthesia were randomly divided into two groups.In Group O patients, ondansetron 4 mg was given intravenouslyat the end of the surgery and 8 mg added to the morphine solutionin the PCA syringe. Patients in Group P received only morphinevia PCA syringe. Analgesia and nausea were measured until PCAwas discontinued 24 h after the operation. Women in the twogroups were similar with respect to age, duration of use ofthe PCA, amount of morphine used, previous history of PONV,and incidence of motion sickness and morning sickness duringthe current pregnancy. The number of women who complained ofnausea and those needing rescue antiemetic medication was significantlyless in Group O. However, there was no statistically significantdifference between the two groups in the patient’s perceptionof the control of nausea and their overall satisfaction. Itwas noted that PONV was more frequent among women who had significantmorning sickness during early pregnancy and ondansetron wasbeneficial in reducing PONV in these women. Although the ondansetronreduced the incidence of PONV and the need for further antiemeticmedication, this did not affect patient’s satisfactionregarding their postoperative care. Br J Anaesth 2001; 87: 502–4     

PATIENT-CONTROLLED ANALGESIA WITH LOW DOSE BACKGROUND INFUSIONS AFTER LOWER ABDOMINAL SURGERY IN CHILDREN

Forty-five children (aged 6–12 yr) undergoing appendicectomyreceived one of three analgesic regimens using patient-controlledanalgesia (PCA) with morphine: no background infusion (BO);background infusion 4 µg kg^–1 h^–1 (B4); backgroundinfusion 10 µh^–1 h^–1 (B10). Total consumptionof morphine was greater in group B10 compared with groups BO(P<0.01) and B4 (P<0.05). There was no significant differencein morphine consumption in groups BO and B4. All three groupsself-administered similar amounts of morphine and there wereno significant differences in pain scores or incidence of excessivesedation. Group B4 suffered less hypoxaemia compared with groupsBO (P<0.01) and B10 (P<0.001). Group B10 suffered morenausea and vomiting than groups BO (P<0.001) and B4 (P<0.001),but there was no significant difference in the incidence ofnausea and vomiting between groups BO and B4. Groups B4 andB10 spent more time at night asleep than group BO (P<0.05).There were no significant differences between the groups inthe amount of time spent asleep during the day. Inclusion ofa background infusion of morphine 4 µg kg^–1 h^–1in a PCA regimen for children did not increase the incidenceof side effects and was associated with less hypoxaemia anda better sleep pattern than no background infusion. (Br. J.Anaesth. 1993; 71: 818–822)     

Cross-tolerance between spinal neostigmine and morphine in the rat

Background. Direct or indirect acting cholinergic muscarinicagonists such as neostigmine, are potent antinociceptives whenadministered intrathecally (i.t.). This study examines whetherspinal neostigmine tolerance and cross-tolerance to spinal morphineoccurs. Methods. Rats (32/group) were implanted with miniosmotic pumpsdelivering either i.t. saline 1 µl h^–1 (S), morphine10 nmol µl^–1 h^–1 (M), or neostigmine 3 nmolµl^–1 h^–1 (N). Latencies (infrared thermalwithdrawal rear paw) were measured daily for 6 days after whichfour animals from each group were given one i.t. challenge doseof morphine (m) 0.1, 1, 10, or 100 nmol, or neostigmine (n)0.3, 3, 10, or 30 nmol. Results. Neostigmine and morphine-infused animals both developedtolerance to spinal neostigmine, but neostigmine-infused animalsshowed no significant cross-tolerance to spinal morphine; meanED₅₀ nmol (CI 95%) dose–response values were Sn 2.6 (1.9–3.5),Mn 15.6 (9.9–24.6)*, Nn 18.7 (11.7–29.8)*, Sm 0.7(0.4–1.1), Nm 1.2 (0.8–2.0), Mm 152 (50–461)*(*significance vs saline infused control group). Conclusion. Thus, unidirectional cross-tolerance from morphineto neostigmine was evident. Previous studies suggest morphinehas a cholinergic mechanism of action partially accounting forits antinociceptive effect, which may explain this observedunidirectional cross-tolerance. Br J Anaesth 2003; 91: 427–9     

Double-blind randomized controlled trial of caudal versus intravenous S(+)-ketamine for supplementation of caudal analgesia in children

Background. The postoperative analgesic efficacy of S(+)-ketamineafter caudal or i.v. administration following sub-umbilicalsurgery in children was studied to investigate its principalsite of analgesic action. Methods. Sixty children undergoing caudal block during generalanaesthesia for hernia repair or orchidopexy were prospectivelyrandomized to one of three groups: the bupivicaine group receivedplain bupivacaine 0.25% 1 ml kg^–1; the caudal ketaminegroup received caudal plain bupivacaine 0.25% 1 ml kg^–1with S(+)-ketamine 0.5 mg kg^–1; the i.v. ketamine groupreceived caudal plain bupivacaine 0.25% 1 ml kg^–1 plusS(+)-ketamine 0.5 mg kg^–1 i.v.. Postoperative measurementsincluded analgesic requirements and modified objective painscore for the first 24 h. Results. The median time to first analgesia was significantlylonger in the caudal ketamine group (10 h) than in the i.v.ketamine (4.63 h) or bupivacaine (4.75 h) groups (P=0.01). Significantlyfewer doses of analgesia were required over the first postoperative24 h by subjects in the caudal ketamine group (median 1) comparedwith the i.v. ketamine (median 2) or bupivacaine (median 2.5)groups (P<0.05). There was no difference between the groupsin the incidence of postoperative nausea and vomiting or psychomotorreactions. Conclusions. We have demonstrated that the addition of caudalS(+)-ketamine to bupivacaine prolongs the duration of postoperativeanalgesia. However, the same dose of i.v. S(+)-ketamine combinedwith a plain bupivacaine caudal provides no better analgesiathan caudal bupivacaine alone, indicating that the principalanalgesic effect of caudal S(+)-ketamine results from a localneuroaxial rather than a systemic effect. Br J Anaesth 2004; 92: 344–7     

Comparison of hyperbaric and plain ropivacaine 15 mg in spinal anaesthesia for lower limb surgery

Background. Previously, plain ropivacaine 15 mg given intrathecallyhas been shown to be feasible for ambulatory surgery of lower-extremities.Hypothetically, hyperbaric solution could improve and shortenthe block. Methods. This prospective, randomized, double-blind study included56 patients undergoing surgery of lower extremities. They receivedintrathecally either 1.5 ml of ropivacaine 10 mg ml^–1and 0.5 ml of glucose 300 mg ml^–1 (HYP) or 2 ml of ropivacaine7.5 mg ml^–1 (PL). Results. All patients in Group HYP achieved T₁₀ dermatome analgesiabut only 64% (18/28) of Group PL. T₁₀ analgesia was reachedin 5 min (median, range 5–20 min) in the HYP group vs10 min (5–45 min) in the PL group (P=0.022), and fullmotor block in 10 min (5–45 min) vs 20 min (5–60min) (P=0.003), respectively. Group HYP had a longer durationof analgesia at T₁₀; 83 min (5–145 min) vs 33 min (0–140min) (P=0.004). Duration of sensory block from injection ofthe anesthetic to complete recovery was shorter in Group HYPthan in Group PL, 210 min (120–270 min) vs 270 min (210–360min) (P<0.001), as was duration of motor block, 120 min (5–150min) vs 210 min (120–330 min) (P<0.001). Patients ofGroup HYP attained discharge criteria earlier than those ofGroup PL (P=0.009). Conclusion. In comparison with the plain solution, 15 mg ofintrathecal hyperbaric ropivacaine produced a faster onset,greater success rate of analgesia at the level of T₁₀ dermatome,and faster recovery of the block.     

Caudal bupivacaine supplemented with caudal or intravenous clonidine in children undergoing hypospadias repair: a double-blind study

Background. Clonidine is used increasingly in paediatric anaestheticpractice to prolong the duration of action of caudal block witha local anaesthetic agent. Which route of administration ofclonidine is the most beneficial remains unknown. We comparedthe effects of caudal and i.v. clonidine on postoperative analgesiaproduced by caudal bupivacaine after hypospadias repair. Methods. Forty-six children (ASA I or II) aged 24–104months received standardized premedication with midazolam, ageneral anaesthetic and a caudal block with bupivacaine 0.25%,0.5 ml kg^–1. The children were randomized in a double-blindfashion to two groups: the i.v. group received clonidine 2 µg kg^–1i.v. and simultaneously the same volume of saline caudally.The caudal group received clonidine 2 µg kg^–1caudally and a similar volume of saline i.v. After surgery,all children received acetaminophen 20 mg kg^–1 rectallyor orally 6-hourly and were given a patient-controlled or nurse-controlledanalgesia (PCA/NCA) pump with i.v. morphine (bolus of 25 µg kg^–1and an 8-min lockout period with no background infusion). Monitoringof scores for pain, sedation, motor block, and postoperativenausea and vomiting was performed by nurses blinded to the studyallocations. Time to first activation of the PCA/NCA pump and0–24 h and 24–48 h morphine consumption were alsorecorded. Results. Forty-four children completed the study. Age, weightand duration of anaesthesia and surgery were similar in thetwo groups. The median (range) time to first activation of thePCA/NCA pump was similar in the two groups: 425 (150–1440)min in the i.v. group and 450 (130–1440) min in the caudalgroup. The number of children not requiring postoperative morphinewas four and seven respectively. Morphine consumption during0–24 h and 24–48 h was similar between groups. Conclusions. The analgesic effect of clonidine 2 µg kg^–1as an adjunct to caudal block with bupivacaine 0.25%, 0.5 ml kg^–1is similar whether administered i.v. or caudally. Br J Anaesth 2004; 92: 223–7