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.     

Pretreatment with remifentanil to prevent withdrawal after rocuronium in children

Background. Pain from rocuronium injection is a common side-effectreported to occur in 50–80% of the patients. This randomized,double-blind, placebo-controlled study was designed to evaluatethe efficacy of pretreatment with i.v. remifentanil on preventionof withdrawal response during rocuronium injection in paediatricpatients. Methods. After obtaining parental consents, 70 paediatric patientswere randomly allocated into two groups to receive either i.v.remifentanil 1 µg kg^–1 (remifentanil group, n=35)or i.v. saline 5 ml (saline group, n=35). Anaesthesia was inducedwith thiopental sodium 2.5% (5 mg kg^–1) and the test drugwas injected over 30 s. One minute after the test drug injection,rocuronium 1% (0.6 mg kg^–1) was injected over 5 s andthe response was recorded. Mean arterial pressure (MAP) andheart rate were recorded on arrival in the operating theatre,before and 1 min after the tracheal intubation. Results. The overall incidence of withdrawal movements was significantlyhigher in the saline group (33 patients; 94%) than that in theremifentanil group (8 patients; 23%) (P<0.001). No patientin the remifentanil group showed generalized movement, whereas51% of patients in the saline group did. Remifentanil preventedsignificant increase in MAP after intubation. Conclusion. This study demonstrated that pretreatment with remifentanil1 µg kg^–1 provided a safe and simple method forreducing the incidence of rocuronium-associated withdrawal movementwith haemodynamic stability in children.     

Effects of AM281, a cannabinoid antagonist, on systemic haemodynamics, internal carotid artery blood flow and mortality in septic shock in rats

Introduction. The purpose of this study was to examine the effectsof AM281, a cannabinoid receptor antagonist, on systemic haemodynamics,internal carotid artery blood flow and mortality during septicshock in rats. Methods. The study included three sets of experiments: measurementsof changes in systemic haemodynamics and left internal carotidartery flow (30 animals divided into three groups of 10); measurementsof biochemical variables (n=30); assessment of mortality (n=30).Male Wistar rats (7 weeks old) were randomly divided into threegroups: group 1, control; group 2, lipopolysaccharide (LPS)i.v., Escherichia coli endotoxin 10.0 mg kg^–1 i.v., bolus;group 3, LPS 10.0 mg kg^–1 i.v.+AM281 1 mg kg^–1 i.v.Systemic haemodynamics, carotid artery flow changes and biochemicalvariables were assessed at pretreatment and 1, 2 and 3 h afterthe treatment was performed. Results. Administration of AM281 could prevent the haemodynamicchanges induced by sepsis. Tumour necrosis factor-     

Effects of intramuscular administration of lidocaine or bupivacaine on induction and maintenance doses of propofol evaluated by bispectral index

Background. Interest in combining local and general anaesthesiahas lead to studies investigating possible interactions. Ina prospective, randomized, double-blind study, we tested whetherlocal anaesthetics administered i.m. potentiate the hypnoticeffect of propofol. Methods. Sixty patients (three groups, n=20) undergoing lowerabdominal surgery with total i.v. propofol anaesthesia wereinvestigated. Patients in Group B received i.m. bupivacaine(5 mg ml^–1) 1 mg kg^–1, patients in Group Lreceived i.m. lidocaine (100 mg ml^–1) 2 mg kg^–1and patients in Group C received i.m. saline 5 ml beforeoperation. Hypnosis was measured with bispectral index (BIS). Results. The induction (BIS <45), and the maintenance dosesof propofol (BIS between 40 and 50) were significantly lessin Group B and Group L compared with the control group. Inductiondoses were 1.58 (SD 0.39), 1.56 (0.24) and 2.03 (0.33) mg kg^–1respectively; P<0.0001. Maintenance doses were 6.33 (2.06),7.08 (1.23) and 9.95 (2.02) mg kg^–1 respectively in thefirst hour; P<0.0001. Groups B and L were associated withan attenuated haemodynamic response to both induction and intubation. Conclusion. I.M. administered local anaesthetics are associatedwith a decrease in both the induction and maintenance dosesof propofol during total i.v. anaesthesia and a reduction inhaemodynamic responses. Br J Anaesth 2002; 89: 849–52     

Effects of xenon anaesthesia on the circulatory response to hypoventilation

Background. Circulatory response to hypoventilation is aimedat eliminating carbon dioxide and maintaining oxygen delivery(DO₂) by increasing cardiac output (CO). The hypothesis thatthis increase is more pronounced with xenon than with isofluraneanaesthesia was tested in pigs. Methods. Twenty pigs received anaesthesia with xenon 0.55 MAC/remifentanil0.5 µg kg^–1 min^–1 (group X, n=10) or isoflurane0.55 MAC/remifentanil 0.5 µg kg^–1min^–1 (groupI, n=10). CO, heart rate (HR), mean arterial pressure (MAP)and left ventricular fractional area change (FAC) were measuredat baseline, after 5 and 15 min of hypoventilation and after5, 15 and 30 min of restored ventilation. Results. CO increased by 10–20% with both anaesthetics,with an equivalent rise in HR, maintaining DO₂ in spite of a20% reduction in arterial oxygen content. Decreased left ventricular(LV) afterload during hypoventilation increased FAC, and thiswas more marked with xenon (0.60–0.66, P<0.05 comparedwith baseline and isoflurane). This difference is attributedto negative inotropic effects of isoflurane. Increased pulmonaryvascular resistance during hypoventilation was found with bothanaesthetics. Conclusion. The cardiovascular effects observed in this modelof moderate hypoventilation were sufficient to maintain DO₂.Although the haemodynamic response appeared more pronouncedwith xenon, differences were not clinically relevant. An increasein FAC with xenon is attributed to its lack of negative inotropiceffects.     

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     

Treatment of ischaemic left ventricular dysfunction with milrinone or dobutamine administered during coronary artery stenosis in the presence of beta blockade in pigs

Background. This study examines the effects of phosphodiesterasetype III (PDEIII) inhibition vs beta stimulation on global functionof the left ventricle (LV) and systemic haemodynamics in a porcinemodel of acute coronary stenosis with beta blockade. Methods. A total of 18 adult swine were anaesthetized. Micromanometer-tippedcatheters were placed in the ascending aorta and LV. Two pairsof ultrasonic dimension transducers were placed in the subendocardiumon the short axis proximal to a left anterior descending (LAD)artery occluder and the long axis of the LV. Before ischaemia,i.v. esmolol was infused to decrease baseline heart rate (HR)by approximately 25%, and all animals received an esmolol infusion(150 µg kg^–1 min^–1). Ischaemia was producedby reducing the flow in the LAD artery by approximately 80%,from 17(4) to 3(2) ml min^–1. Animals were randomized toreceive (after esmolol) one of the following: no drug, shamonly (Group 1, n=6), control (C); 50 µg kg^–1 i.v.milrinone (Group 2, n=6) followed by 0.375 µg kg^–1min^–1 (M); or incremental doses of dobutamine (Group 3,n=6) every 10 min (5, 10 and 20 µg kg^–1 min^–1)(D). Left ventricular function data obtained included HR, arterialand LV pressures, cardiac output (CO), Emax and dP/dT. Measurementswere taken during five time periods: before ischaemia (at baseline,after esmolol) and every 10 min during ischaemia (at 10, 20and 30 min). Results. The effects of beta blockade and ischaemia had a significantimpact on contractility (Emax) in Group M and myocardial performance(left ventricular end-diastolic pressure, LVEDP) in all groups.Left ventricular function (Emax, CO, LVEDP and SVR) was betterpreserved when milrinone was added in Group M. A moderate doseof dobutamine (10 µg kg^–1 min^–1) increasedCO. Only the high dose (20 µg kg^–1 min^–1)improved contractility (Emax), but at the expense of increasedSVR. Also, LVEDP with either dose of dobutamine remained highand unchanged. Conclusions. From our limited findings, it would appear thatthere may, theoretically, be some benefit for using milrinonein preference to other inotropic drugs in the presence of betablockade. Milrinone administration should be considered in patientswith acute ischaemic LV dysfunction and preexisting beta blockadebefore using other inotropic drugs such as beta stimulants. Presented in part at: the 27th Annual Meeting of the Societyof Cardiovascular Anesthesiologists, May 14–18, 2005,Baltimore, MD, USA (Anesth Analg 2005; 100: 5CA60).     

Comparison of the effects of thoracic epidural analgesia and i.v. infusion with lidocaine on cytokine response, postoperative pain and bowel function in patients undergoing colonic surgery

Background. Both thoracic epidural analgesia (TEA) and i.v.lidocaine were able to decrease postoperative pain and durationof ileus. We compared TEA and i.v. lidocaine (IV) regardingtheir effects on cytokines, pain and bowel function after colonicsurgery. Methods. Sixty patients were randomly allocated to one of thethree groups. TEA group had lidocaine 2 mg kg^–1 followedby 3 mg kg^–1 h^–1 epidurally and an equal volumeof i.v. normal saline. The IV group received the same amountof lidocaine i.v. and normal saline epidurally. The controlgroup received normal saline via both routes. These regimenswere started 30 min before surgery and were continued throughout.Blood cytokines were measured at scheduled times within 72 h. Results. Both TEA and IV groups had better pain relief. Thetotal consumptions using patient-controlled epidural analgesiawere 81.6 (6.5), 55.0 (5.3) and 45.6 (3.9) ml (P<0.01) andthe times of flatus passage were 50.2 (4.9), 60.2 (5.8) and71.7 (4.7) h (P<0.01) in the TEA, IV and control groups,respectively. The TEA group exhibited the best postoperativepain relief and the least cytokine surge. The IV group experiencedbetter pain relief and less cytokine release than the controlgroup. Conclusions. The TEA lidocaine had better pain relief, loweropioid consumption, earlier return of bowel function and lesserproduction of cytokines than IV lidocaine during 72 h aftercolonic surgery; IV group was better than the control group.     

Evaluation of effects of magnesium sulphate in reducing intraoperative anaesthetic requirements

Background. The present randomized, placebo-controlled, double-blindstudy was designed to assess the effect of peroperatively administeredi.v. magnesium sulphate on anaesthetic and analgesic requirementsduring total i.v. anaesthesia. Methods. Eighty-one patients (36 women, 45 men) undergoing electivespinal surgery were included in one of two parallel groups.The magnesium group received magnesium sulphate 30 mg kg^–1as a bolus before induction of anaesthesia and 10 mg kg^–1h^–1 by continuous i.v. infusion during the operation period.The same volume of isotonic solution was administered to thecontrol group. Anaesthesia was maintained with propofol (administeredaccording to the bispectral index) and remifentanil (adjustedaccording to heart rate and arterial blood pressure) infusions. Results. A significant reduction in hourly propofol consumptionwas observed with magnesium administration. For example, themean infusion rate of propofol in the second hour of the operationwas 7.09 mg kg^–1 h^–1 in the controlgroup vs 4.35 mg kg^–1 h^–1 in themagnesium group (P<0.001). The magnesium group required significantlyless remifentanil (P<0.001) and vecuronium (P<0.001).No side-effects were observed with magnesium administration. Conclusion. The administration of magnesium led to a significantreduction in the requirements for anaesthetic drugs during totali.v. anaesthesia with propofol, remifentanil and vecuronium. Br J Anaesth 2002; 89: 594–8     

Parecoxib sodium has opioid-sparing effects in patients undergoing total knee arthroplasty under spinal anaesthesia

Background. This multicentre, double-blind, placebo-controlledstudy compared the opioid-sparing effectiveness and clinicalsafety of parecoxib sodium over 48 h, in 195 postoperativepatients after routine total knee replacement surgery. Methods. Elective total primary knee arthroplasty was performedunder spinal anaesthesia, with a single dose of spinal bupivacaine10–20 mg, and intraoperative sedation with midazolam0.5–1.0 mg i.v., or propofol <6 mg kg^–1h^–1. Patients were randomized to receive either parecoxibsodium 20 mg twice daily (bd) i.v. (n=65), parecoxib sodium40 mg bd i.v. (n=67), or placebo (n=63) at the completionof surgery, and after 12, 24, and 36 h. Morphine (1–2 mg)was taken by patient-controlled analgesia or by bolus dosesafter 30 min. Results. Patients receiving parecoxib sodium 20 mg bd and40 mg bd consumed 15.6% and 27.8% less morphine at 24 hthan patients taking placebo (both P<0.05). Both doses ofparecoxib sodium administered with morphine provided significantlygreater pain relief than morphine alone from 6 h (P<0.05).A global evaluation of study medication demonstrated a greaterlevel of satisfaction among patients taking parecoxib sodiumthan those taking placebo. Parecoxib sodium administered incombination with morphine was well tolerated. However, a reductionin opioid-type side-effects was not demonstrated in the parecoxibsodium groups. Conclusion. Parecoxib sodium provides opioid-sparing analgesiceffects in postoperative patients. Br J Anaesth 2003; 90: 166–72     

Tracheal intubating conditions and apnoea time after small-dose succinylcholine are not modified by the choice of induction agent

Background. In a randomized, double-blind clinical trial, westudied the effect of different i.v. induction drugs on trachealintubation conditions and apnoea time after small-dose (0.6mg kg^–1) succinylcholine used to facilitate orotrachealintubation at an urban, university-affiliated community medicalcentre. Methods. One hundred and seventy-five ASA I and II adult patientsscheduled to undergo surgical procedures requiring general anaesthesiaand tracheal intubation were allocated to one of five groupsaccording to i.v. anaesthetic induction drug used. General anaesthesiawas induced by i.v. administration of lidocaine 30 mg and propofol2.5 mg kg^–1 (Group 1), thiopental 5 mg kg^–1 (Group2), lidocaine 30 mg and thiopental 5 mg kg^–1 (Group 3),etomidate 0.3 mg kg^–1 (Group 4), or lidocaine 30 mg andetomidate 0.3 mg kg^–1 (Group 5). After loss of consciousness,succinylcholine 0.6 mg kg^–1 was given i.v. followed bydirect laryngoscopy and tracheal intubation after 60 s. Measurementsincluded intubation conditions recorded during laryngoscopy60 s after succinylcholine administration, and apnoea time. Results. Overall, clinically acceptable intubation conditionswere met in 168 out of the 175 patients studied (96%). Theywere met in 35/35 patients in Group 1, 33/35 patients in Group2, 34/35 patients in Group 3, 33/35 patients in Group 4, and33/35 patients in Group 5. Mean (SD) apnoea time was 4.0 (0.4),4.2 (0.3), 4.2 (0.6), 4.1 (0.2) and 4.1 (0.2) min respectivelyin Groups 1–5. There were no differences in the intubationconditions or apnoea times between the groups. Conclusions. The use of succinylcholine 0.6 mg kg^–1 producedthe same favourable intubation conditions and a short apnoeatime regardless of the induction drug used.     

Efficacy of three doses of tramadol with bupivacaine for caudal analgesia in paediatric inguinal herniotomy

Background. This study was designed to evaluate the analgesicefficacy of three doses of tramadol, administered caudally withbupivacaine, in providing postoperative pain relief in children. Methods. Eighty children, aged between 2 and 8 yr, undergoinginguinal herniotomy were randomly allocated to receive bupivacaine0.25% 0.75 ml kg^–1 (Group B; n=20), bupivacaine 0.25%0.75 ml kg^–1 with tramadol 1 mg kg^–1 (Group BT1;n=20), bupivacaine 0.25% 0.75 ml kg^–1 with tramadol 1.5mg kg^–1 (Group BT1.5; n=20), or bupivacaine 0.25% 0.75ml kg^–1 with tramadol 2 mg kg^–1 (Group BT2; n=20)by the caudal route immediately after induction of general anaesthesia.Heart rate, arterial pressure and oxygen saturation were monitored.Postoperative pain was assessed at regular intervals for 24h using All India Institute of Medical Sciences pain score.Analgesia was supplemented whenever pain score was 4. Durationof analgesia and requirement for additional analgesics was noted. Results. Duration of analgesia was longer in Group BT2 [(mean(SD) 12 (0.9) h] compared with Group B [4 (1) h], Group BT1[8 (0.9) h], or Group BT1.5 [11 (1) h]; all P<0.001. Totalconsumption of rescue analgesic was significantly lower in groupBT2 compared with other groups (P<0.001). There were no significantchanges in heart rate, arterial pressure and oxygen saturationbetween groups. Adverse effects were not observed. Conclusions. Caudal tramadol 2 mg kg^–1, combined withbupivacaine 0.25% 0.75 ml kg^–1, provided longer durationof postoperative analgesia and reduced requirement for rescueanalgesic compared with tramadol 1 mg kg^–1 or 1.5 mg kg^–1in children undergoing inguinal herniotomy.     

Effect of prophylactic bronchodilator treatment with i.v. carperitide on airway resistance and lung compliance after tracheal intubation

Background. Lung resistance increases after induction of anaesthesia.We hypothesized that prophylactic bronchodilation with i.v.carperitide before tracheal intubation would decrease airwayresistance and increase lung compliance after placement of thetracheal tube in both smokers and nonsmokers. Methods. Ninety-seven adults aged between 24 and 59 yr wererandomized to receive i.v. normal saline (0.9% saline) (control)or carperitide, 0.2 µg kg^–1 min^–1 throughoutthe study. The 97 patients included smokers and nonsmokers.Thus the patients were allocated to one of the four groups:smokers who received normal saline (n=21), nonsmokers who receivednormal saline (n=27), smokers who received carperitide (n=19)or nonsmokers who received carperitide (n=30). Thirty minutesafter starting normal saline or carperitide infusion, we administeredthiamylal 5 mg kg^–1 and fentanyl 5 µg kg^–1to induce general anaesthesia and vecuronium 0.3 mg kg^–1for muscle relaxation. Continuous infusion of thiamylal 15 mgkg^–1 h^–1 followed anaesthetic induction. Mean airwayresistance (R_awm), expiratory airway resistance (R_awe) and dynamiclung compliance (C_dyn) were determined 4, 8, 12 and 16 min aftertracheal intubation and compared between the four groups. Results. At 4 min after intubation, R_awm and R_awe were higherand C_dyn lower in smokers than in nonsmokers in the controlgroup. R_awm and R_awe were lower and C_dyn higher in smokers inthe carperitide group than in smokers in the control group.R_awm and R_awe were lower in nonsmokers in the carperitide groupthan in nonsmokers in the control group. Conclusions. Marked bronchoconstriction occurred in the controlgroups (smokers and nonsmokers) 4 min after tracheal intubation.Prophylactic treatment with carperitide before induction ofanaesthesia and tracheal intubation was advantageous, particularlyin smokers.     

Sevoflurane and propofol decrease intraocular pressure equally during non-ophthalmic surgery and recovery

Background. To provide good control of intraocular pressure(IOP) during anaesthesia and surgery, we conducted a study comparingthe effects on IOP during maintenance and recovery of sevofluranevs propofol anaesthesia in 33 patients (ASA I–II) undergoingelective non- ophthalmic surgery. Methods. Anaesthesia was induced with propofol 2 mg kg^–1,fentanyl 2 µg kg^–1 and vecuronium 0.1 mg kg^–1.Patients were allocated randomly to receive either propofol4–8 mg kg^–1 h^–1 (group P; n=16)or 1.5–2.5 vol% sevoflurane (group S; n=17) for maintenanceof anaesthesia. Fentanyl 2–4 µg kg^–1was added if necessary. The lungs were ventilated with 50% airin oxygen. Blood pressure, heart rate, oxygen saturation andend-tidal carbon dioxide were measured before and throughoutanaesthesia and in the recovery room. IOP was determined withapplanation tonometry (Perkins) by one ophthalmologist blindedto the anaesthetic technique. Results. There was a significant decrease in IOP after inductionand during maintenance of anaesthesia in both groups. No significantdifferences in IOP between the two groups was found. Conclusion. Sevoflurane maintains the IOP at an equally reducedlevel compared with propofol. Br J Anaesth 2002; 89: 764–6     

Propofol injection pain in children: a prospective randomized double-blind trial of a new propofol formulation versus propofol with added lidocaine

Background. The incidence of pain on injection of propofol remainsunacceptably high in children, despite various strategies toreduce it. A new drug formulation of propofol has, in adultstudies, been reported to cause less injection pain comparedwith other propofol solutions. The aim of the present prospectiverandomized double-blind clinical trial was to compare the incidenceof pain-free injection following the use of this new formulationwith that following the use of propofol with added lidocainein children undergoing day case surgery. Methods. Eighty-three children (age range 2–18 yr) wererandomized to receive 3 mg kg^–1 of either Propofol-Lipuro®(propofol dissolved in a mixture of medium- and long-chain triglycerides[MCT–LCT]; group pL, n=42) or Diprivan® (propofoldissolved in long-chain triglycerides [LCT]) with added lidocaine(0.3 mg kg^–1) (group pD, n=41). A specially trained nurseanaesthetist assessed the occurrence of injection pain usinga four-graded pain scale. Results. Significantly fewer patients had an entirely pain-freepropofol injection in group pL (33.3%) than in group pD (61.0%)(P=0.016). Conclusions. A new MCT–LCT propofol formulation as a plainsolution was associated with a higher incidence of injectionpain than LCT propofol with added lidocaine when used for inductionof anaesthesia in children.     

Comparison of mepivacaine and lidocaine for intravenous regional anaesthesia: pharmacokinetic study and clinical correlation

Background. Limitations to the use of lidocaine for intravenousregional anaesthesia (IVRA) include lack of optimal intraoperativeanalgesia and systemic toxic reactions.This randomized double-blindstudy was conducted to compare intraoperative and postoperativeanalgesia, adverse effects, and plasma concentrations of mepivacaineor lidocaine, on release of the tourniquet in patients undergoingIVRA for distal upper limb surgery. Methods. Forty-two adult patients were randomly allocated toreceive either a 0.5% lidocaine solution 3 mg kg^–1 (n=20)or mepivacaine 5 mg kg^–1 (n=22). Plasma concentrationsof both anaesthetic agents were measured at 5, 10, 20, 30, 45,and 60 min after deflation of the tourniquet by gas chromatography. Results. Although plasma concentrations of mepivacaine and lidocainewere comparable 5 min after deflation, concentrations of lidocainedecreased significantly thereafter, whereas plasma concentrationsof mepivacaine were similar over the 60-min study period. Supplementaryanalgesia during the intraoperative period was required by 45%of patients in the lidocaine group as compared with 9% in themepivacaine group (P=0.02). No adverse effects were observedin patients given mepivacaine. In the lidocaine group, adverseeffects were observed in 10% of the patients. The total ischaemiatime, volume of the local anaesthetic, and duration of the surgicalprocedure were not significantly different between the two groups. Conclusions. Mepivacaine 5 mg kg^–1 ensured better intraoperativeanalgesia than lidocaine 3 mg kg^–1 when used for IVRA.Plasma concentrations of lidocaine decreased significantly between5 and 60 min following tourniquet deflation, whereas blood concentrationsof mepivacaine remained below the toxic concentration. Br J Anaesth 2002; 88: 516–19     

Role of propofol and its solvent,intralipid, in nitric oxide-induced peripheral vasodilatation in dogs

Background. The commercial propofol preparation in an intralipidsolution causes marked vasodilatation. Both propofol and itssolvent seem to stimulate the nitric oxide (NO) pathway. Therole of intralipid in cardiac and regional haemodynamic changesinduced by propofol and their respective interactions with theNO pathway was assessed. Methods. Dogs were instrumented to record arterial pressure,heart rate, cardiac output, dP/dt (the first derivative of leftventricular pressure) and vertebral, carotid, coronary, mesenteric,hepatic, portal and renal blood flows. Experimental groups wereas follows. Group 1 (control; n=11): N-methyl-L-arginine (L-NMA)20 mg kg^–1 i.v.; Group 2 (n=8): propofol (10mg ml^–1) 4 mg kg^–1 i.v. bolus followedby 0.6 mg kg^–1 min^–1; Group 3 (n=6):intralipid 0.25 ml kg^–1 bolus followed by 0.06ml kg^–1 min^–1. After 60 min, L-NMAwas injected in Groups 2 and 3. Results. Propofol induced increases in heart rate, coronaryand carotid blood flows, and decreases in systemic vascularresistance and dP/dt. Intralipid increased renal blood flow,carotid vascular resistance and mesenteric vascular resistance.In the presence of intralipid, L-NMA-induced pressor responseand systemic, carotid and renal vasoconstriction were more pronouncedthan in control dogs. Conclusions. Except for the coronary and carotid circulations,intralipid modulates the NO pathway in cardiac and regionalblood flow. Br J Anaesth 2002; 89: 492–8     

Amrinone can accelerate the cooling rate of core temperature during deliberate mild hypothermia for neurosurgical procedures

We investigated the effects of i.v. amrinone on intraoperativechanges of core temperature during deliberate mild hypothermiafor neurosurgery. The patients in a control group (n=10) didnot receive amrinone and patients in the amrinone group (n=10)received amrinone 5 µg kg^–1 min^–1after a loading dose of 1.0 mg kg^–1. Anaesthesiawas maintained with nitrous oxide in oxygen, propofol and fentanyl.After the induction of anaesthesia, patients were cooled andtympanic membrane temperature was maintained at 34.5°C.After completion of the main surgical procedures, patients wererewarmed in the operating room. Tympanic membrane temperaturesbetween 30 and 90 min after cooling were significantly lowerin the amrinone group than in the control group. During cooling,the times taken to cool to 35°C and to the lowest temperaturewere significantly shorter in the amrinone group than in thecontrol group. These results suggest that i.v. amrinone canaccelerate the cooling rate of core temperature during deliberatemild hypothermia for neurosurgical procedures. Br J Anaesth 2001; 86: 663–8     

Effect of fibrinogen on reversal of dilutional coagulopathy: a porcine model

Background. This study was conducted to determine whether replacementof fibrinogen is useful in reversing dilutional coagulopathyfollowing severe haemorrhage and administration of colloids. Methods. In 14 anaesthetized pigs, approximately 65% of theestimated blood volume was withdrawn and replaced with the sameamount of gelatin solution to achieve dilutional coagulopathy.Animals were randomized to receive either 250 mg kg^–1fibrinogen (n=7) or normal saline (n=7). A standardized liverinjury was then inflicted to induce uncontrolled haemorrhage.Modified thrombelastography and standard coagulation tests wereperformed at baseline, after blood withdrawal, after dilution,after injection of the study drugs, and on conclusion of theprotocol. Further, electron microscopy imaging of the bloodclots was performed and blood loss after liver injury was determined. Results. Severely impaired haemostasis was observed after haemodilutionwith gelatin substitution. With administration of fibrinogen,clot firmness and dynamics of clot formation reached baselinevalues. Median blood loss following liver injury was significantlyless (P=0.018) in the fibrinogen-treated animals (1100 ml; 800–1400ml) than in the placebo group (2010 ml; 1800–2200 ml). Conclusions. Replacing 65% of the estimated blood volume withgelatin in swine resulted in dilutional coagulopathy; subsequentfibrinogen administration improved clot formation and reducedblood loss significantly.     

Increased carbon dioxide absorption during retroperitoneal laparoscopy

Background. Retroperitoneoscopy for renal surgery is now a commonprocedure. We compared carbon dioxide absorption in patientsundergoing retroperitoneoscopy for adrenal or renal surgerywith that of patients undergoing laparoscopic cholecystectomy. Methods. We measured carbon dioxide elimination with a metabolicmonitor in 30 anaesthetized patients with controlled ventilation,undergoing retroperitoneoscopy (n=10), laparoscopy (n=10) ororthopaedic surgery (n=10). Results. Carbon dioxide production increased by 38, 46 and 63%at 30, 60 and 90 min after insufflation (P<0.01) in patientshaving retroperitoneoscopy. Carbon dioxide production (mean(SD)) increased from 92 (21) to 150 (43) ml min^–1 m^–260–90 min after insufflation and remained increased afterthe end of insufflation. During laparoscopy, V^·_CO2 increasedless (by 15%) (P<0.05 compared with retroperitoneoscopy)and remained steady throughout the procedure. Conclusion. Retroperitoneal carbon dioxide insufflation causesmore carbon dioxide absorption than intraperitoneal insufflation,and controlled ventilation should be increased if hypercapniashould be avoided. Br J Anaesth 2003; 91: 793–6