Assessment of preoperative fluid depletion using bioimpedance analysis

Background. Fluid depletion during the perioperative periodis associated with poorer outcome. Non-invasive measurementof total body water by bioimpedance may enable preoperativefluid depletion and its influence on perioperative outcome tobe assessed. Methods. Weight and foot bioimpedance were recorded under standardizedconditions in patients undergoing bowel preparation (n=43) orday surgery (n=44). Fifteen volunteers also followed standardnil-by-mouth instructions on two separate occasions to assessthe variabilities of weight and bioimpedance over time. Results. Body weight fell by 1.27 kg (95% CI 1.03–1.50kg; P<0.0001) and foot bioimpedance increased by 51 ohm afterbowel preparation (95% CI 36–66; P<0.0001). Weightchange after the nil-by-mouth period in day-surgery patients(mean –0.22 kg, 95% CI –0.05 to –0.47 kg;P=0.07) correlated (r=–0.46; P=0.005) with an increasein bioimpedance (16 ohms, 95% CI 5–27 ohms; P=0.01). Nodifference between two separate bioimpedance measurements wasseen in the volunteer group. Conclusions. Further work is warranted to determine if bioimpedancechanges may serve as a useful indicator of perioperative fluiddepletion. Br J Anaesth 2004; 92: 134–6     

Detection of cerebral hypoperfusion with bispectral index during paediatric cardiac surgery

Background. The bispectral index (BIS) may indicate changesin cerebral activity when the cerebral circulation is affectedby acute hypotension. Methods. We measured BIS and cerebral haemoglobin saturation(Sr_O2) by near-infrared spectroscopy in 10 children undergoingcardiac surgery. Results. We noted 14 episodes of simultaneous decreases in Sr_O2and BIS during acute hypotension in five children. An acutedecrease in BIS, which coincided with a decrease in Sr_O2 suggestinga reduction in cerebral blood flow, was associated with acuteslowing of the raw EEG waveforms. Conclusions. Our findings suggest that an acute decrease inBIS during acute hypotension indicates cerebral hypoperfusion,and that cerebral hypoperfusion caused by hypotension may occurfrequently during paediatric cardiac surgery. Br J Anaesth 2003; 90: 694–8     

Effect of intrathecal tramadol administration on postoperative pain after transurethral resection of prostate

Background. Tramadol administered epidurally has been demonstratedto decrease postoperative analgesic requirements. However, itseffect on postoperative analgesia after intrathecal administrationhas not yet been studied. In this double-blind, placebo-controlledstudy, the effect of intrathecal tramadol administration onpain control after transurethral resection of the prostate (TURP)was studied. Methods. Sixty-four patients undergoing TURP were randomizedto receive bupivacaine 0.5% 3 ml intrathecally premixed witheither tramadol 25 mg or saline 0.5 ml. After operation, morphine5 mg i.m. every 3 h was administered as needed for analgesia.Postoperative morphine requirements, visual analogue scale forpain at rest (VAS) and sedation scores, times to first analgesicand hospital lengths of stay were recorded by a blinded observer. Results. There were no differences between the groups with regardto postoperative morphine requirements (mean (SD): 10.6 (7.9)vs 9.1 (5.5) mg, P=0.38), VAS (1.6 (1.2) vs 1.2 (0.8), P=0.18)and sedation scores (1.2 (0.3) vs 1.2 (0.2), P=0.89). Timesto first analgesic (6.3 (6.3) vs 7.6 (6.2) h, P=0.42) and lengthof hospital stay (4.7 (2.8) vs 4.4 (2.2) days, P=0.66) weresimilar in the two groups. Conclusion. Intrathecal tramadol was not different from salinein its effect on postoperative morphine requirements after TURP. Br J Anaesth 2003; 91: 536–40     

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     

Dopexamine reverses colonic but not gastric mucosal perfusion defects in lethal endotoxin shock

Background. Whilst dopexamine appears to increase overall splanchnicblood flow in postoperative and septic patients, the effectson gastric mucosal perfusion are controversial and based onconcomitantly increasing mucosal to arterial PCO₂ gradients(PdCO₂). We hypothesized that dopexamine alters splanchnic bloodflow distribution and metabolism during experimental endotoxinshock and modifies the inflammatory response induced by endotoxin. Methods. In an experiment with anaesthetized normovolaemic,normoventilated pigs, 21 animals were randomized into: (i) subacutelethal endotoxin shock for 14 h (n=7 at baseline); (ii)endotoxin shock with dopexamine infusion (aiming to exceed baselinecardiac output, n=7); or (iii) controls (n=7). Regional bloodflow and metabolism were monitored. Results. Endotoxin produced a hypodynamic phase followed bya normo/hyperdynamic, hypotensive phase. Despite increasingsystemic blood flow in response to dopexamine, proportionalsplanchnic blood flow decreased during the hypodynamic phase.Dopexamine gradually decreased fractional coeliac trunk flow,while fractional superior mesenteric arterial flow increased.Dopexamine induced early arterial hyperlactataemia and augmentedthe gastric PdCO₂ gradient while colonic luminal lactate releaseand colonic PdCO₂ gradient were reversed. Dopexamine did notmodify the inflammatory response as evaluated by arterial IL-1ßand IL-6 concentrations. Conclusions. Dopexamine protects colonic, but not gastric mucosalepithelium in experimental endotoxin shock. This may be relatedto redistribution of blood flow within the splanchnic circulation. Br J Anaesth 2003; 91: 878–85     

Endotoxaemia during left ventricular assist device insertion: relationship between risk factors and outcome

Background. Endotoxaemia, caused by splanchnic ischaemia duringsurgery, is believed to trigger systemic inflammation and causepostoperative organ dysfunction. A relationship between theplasma concentration of endotoxin during surgery and known riskfactors for postoperative morbidity and mortality (e.g. age,abnormal gastric tonometric variables) and adverse outcome aftersurgery has not been demonstrated. Methods. In a prospective study, the plasma concentration ofendotoxin was measured in 12 patients undergoing implantationof a left ventricular assist device. Automated air gastric tonometrywas performed in all patients. The relationship between plasmaendotoxin concentration, risk factors, and postoperative outcomewas explored. Results. Carbon dioxide gap increased from 0.7 (0.3) to 3.6(1.6) kPa at the end of surgery. Endotoxin was detected in oneof 12 patients at baseline and in nine of 12 patients at theend of surgery (P=0.003). A high plasma concentration of endotoxinat the end of surgery was associated with a higher carbon dioxidegap (r=0.59, P<0.05), and a higher postoperative multipleorgan dysfunction score (r=0.7, P=0.01). Conclusions. The finding of an association between high intraoperativeplasma concentrations of endotoxin, abnormal gastric tonometricvariables and adverse outcome supports the view that endotoxaemiais caused by gut hypoperfusion during surgery and is associatedwith postoperative organ dysfunction. Br J Anaesth 2004; 92: 131–3     

Adjunctive analgesia with intravenous propacetamol does not reduce morphine-related adverse effects

Background. Propacetamol is widely used in the management ofpostoperative pain. It decreases morphine requirements but itseffect on the incidence of morphine-related adverse effectsremains unknown. Methods. Patients (550) were randomly assigned to receive propacetamolor a placebo over the first 24 h after operation in a blindedstudy. Intravenous morphine titration was performed, after whichmorphine was administered s.c. every 4 h according to theirpain score. Pain was assessed using a visual analogue scale(VAS). The primary end-point was the incidence of morphine-relatedadverse effects. The main secondary end-points were morphinerequirements and VAS score. Results. After morphine titration, the VAS score and the numberof patients with pain relief did not differ between groups.Morphine requirements were decreased in the propacetamol group(21 vs 14.5 mg, P<0.001) but the incidence of morphine-relatedadverse effects did not differ between groups (42 vs 46%, notsignificant). In patients with moderate pain (n=395), morphinerequirements decreased by 37% (P<0.001) and the percentageof patients requiring no morphine was greater (21 vs 8%, P=0.002)in the propacetamol group. In patients with severe pain (n=155),morphine requirements decreased by 18% (P=0.04) in the propacetamolgroup and the number of patients who did not require morphine(3 vs 8%) did not differ significantly. Conclusions. Although propacetamol induced a small morphine-sparingeffect, it did not change the incidence of morphine-relatedadverse effects in the postoperative period. Moreover, no benefitcould be demonstrated in patients with severe postoperativepain. Br J Anaesth 2003; 90: 314–19     

Does bispectral analysis of the electroencephalogram add anything but complexity?

Background. Analysis of the bispectrum of EEG waveforms is acomponent of the proprietary BIS index—a commonly usedcommercial monitor of depth of anaesthesia. Does the use ofthe bispectrum give more information about depth of anaesthesiathan the power spectrum? Methods. We collected and analysed EEG waveforms during inductionof general anaesthesia in 39 patients, comparing the changesin bispectral parameter (SynchFastSlow), with an analogous powerspectrum-based parameter (PowerFastSlow). Both compare the logarithmicratio of high frequency components (40–47 Hz) with thetotal (1–47 Hz). Because the changes in bispectrum areaffected by signal amplitude, we also calculated a third parameter(SFSbicoh) from the bicoherence, which is an amplitude-independentstatistic. Results. The SynchFastSlow and PowerFastSlow were correlated(r=0.84) and neither was superior in predicting the awake oranaesthetized state (area under receiver operating characteristiccurves = 0.85 vs 0.93). There was no change in the SFSbicohover the induction period, and it did not correlate with SynchFastSlow(r=0.07). Conclusions. We could not show that bispectral analysis gavemore information than power spectral-based analysis. Most ofthe changes in the bispectral values result from decreases inthe relative high frequency content of the EEG caused by anaesthesia. Br J Anaesth 2004; 92: 8–13     

Desflurane compared with propofol for postoperative sedation in the intensive care unit

Background. We hypothesized that emergence from sedation inpostoperative patients in the intensive care unit would be fasterand more predictable after sedation with desflurane than withpropofol. Methods. Sixty patients after major operations were allocatedrandomly to receive either desflurane or propofol. The targetlevel of sedation was defined by a bispectral index^TM (BIS^TM)of 60. All patients were receiving mechanical ventilation ofthe lungs for 10.6 (SD 5.5) h depending on their clinical state.The study drugs were stopped abruptly in a calm atmosphere withthe fresh gas flow set to 6 litres min^–1, and the timeuntil the BIS increased above 75 was measured (t_BIS75, the mainobjective measure). After extubation of the trachea, when thepatients could state their birth date, they were asked to memorizefive words. Results. Emergence times were shorter (P<0.001) after desfluranethan after propofol (25th, 50th and 75th percentiles): t_BIS75,3.0, 4.5 and 5.8 vs 5.2, 7.7 and 10.3 min; time to first response,3.7, 5.0 and 5.7 vs 6.9, 8.6 and 10.7 min; time to eyes open,4.7, 5.7 and 8.0 vs 7.3, 10.5 and 20.8 min; time to squeezehand, 5.1, 6.5 and 10.2 vs 9.2, 11.1 and 21.1 min; time to trachealextubation, 5.8, 7.7 and 10.0 vs 9.7, 13.5 and 18.9 min; timeto saying their birth date, 7.7, 10.5 and 15.5 vs 13.0, 19.4and 31.8 min. Patients who received desflurane recalled significantlymore of the five words. We did not observe major side-effectsand there were no haemodynamic or laboratory changes exceptfor a more marked increase in systolic blood pressure afterstopping desflurane. Using a low fresh gas flow (air/oxygen1 litre min^–1), pure drug costs were lower for desfluranethan for propofol (95 vs 171 Euros day^–1). Conclusions. We found shorter and more predictable emergencetimes and quicker mental recovery after short-term postoperativesedation with desflurane compared with propofol. Desfluraneallows precise timing of extubation, shortening the time duringwhich the patient needs very close attention. Br J Anaesth 2003; 90: 273–80     

Efficacy of intravenous magnesium in neuropathic pain

Background. Postherpetic neuralgia is a complication of acuteherpes zoster characterized by severe pain and paraesthesiain the skin area affected by the initial infection. There isevidence that the N-methyl-D-aspartate receptor is involvedin the development of hypersensitivity states and it is knownthat magnesium blocks the N-methyl-D-aspartate receptor. Method. A double-blind, placebo-controlled, cross-over studywas conducted in which magnesium sulphate was administered asan i.v. infusion. Spontaneous pain was recorded and qualitativesensory testing with cotton wool was performed in seven patientswith postherpetic neuralgia before and after the i.v. administrationof either magnesium sulphate 30 mg kg^–1 or saline. Results. During the administration, pain scores were significantlylower for magnesium compared with placebo at 20 and 30 min (P=0.016)but not at 10 min. I.V. magnesium sulphate was safe, well-toleratedand effective in patients with postherpetic neuralgia. Conclusion. The present study supports the concept that theN-methyl-D-aspartate receptor is involved in the control ofpostherpetic neuralgia. Br J Anaesth 2002; 89: 711–14     

Stereoselective in vitro degradation pattern of mivacurium in human plasma

Background. Mivacurium is a mixture of three isomers, two ofwhich are rapidly broken down in vivo by plasma cholinesterases.This study investigates the stereospecificity of mivacuriumin vitro degradation to determine if it accounts for its invivo behaviour. Methods. The in vitro rate of degradation of each isomer ofmivacurium and the in vitro rate of formation of their primary(monoesters and alcohols) and secondary (alcohols) metaboliteswere examined using human plasma from six healthy volunteers.The in vitro rate of degradation of the monoester metaboliteswas also assessed. All these determinations were made usinga stereospecific high-performance liquid chromatography assay. Results. The in vitro rate of disappearance of the two activeisomers of mivacurium was very rapid, with mean values for thetrans trans and cis trans isomers of 0.803 and 0.921 min^–1respectively. These values are twofold faster than publishedin vivo data. The in vitro rate of disappearance was much slowerfor the cis cis isomer, with a mean value of 0.0106 min^–1.The cis trans isomer was converted exclusively to cis monoesterand trans alcohol, while only metabolites in the trans and cisconfiguration were found for the trans trans and cis cis isomersrespectively. Mean in vitro rates of disappearance for the transand cis monoester were 0.00750 and 0.000633 min^–1respectively. Conclusions. The in vitro rates of hydrolysis of the activeisomers of mivacurium confirm that plasma cholinesterases playa major role in their in vivo degradation, but that in vivoelimination is slowed by extravascular distribution. Mivacuriumhydrolysis is stereoselective, the ester group in the transconfiguration being more accessible to enzymatic attack. Thisstereoselective pattern, along with the relatively slow breakdownof the cis cis isomer, sheds light on the in vivo dispositionof the cis alcohol metabolite. Br J Anaesth 2002; 89: 832–8     

Patient well-being after general anaesthesia: a prospective, randomized, controlled multi-centre trial comparing intravenous and inhalation anaesthesia

Background. The aim of this study was to assess postoperativepatient well-being after total i.v. anaesthesia compared withinhalation anaesthesia by means of validated psychometric tests. Methods. With ethics committee approval, 305 patients undergoingminor elective gynaecologic or orthopaedic interventions wereassigned randomly to total i.v. anaesthesia using propofol orinhalation anaesthesia using sevoflurane. The primary outcomemeasurement was the actual mental state 90 min and 24 h afteranaesthesia assessed by a blinded observer using the AdjectiveMood Scale (AMS) and the State-Trait-Anxiety Inventory (STAI).Incidence of postoperative nausea and vomiting (PONV) and postoperativepain level were determined by Visual Analogue Scale (VAS) 90min and 24 h after anaesthesia (secondary outcome measurements).Patient satisfaction was evaluated using a VAS 24 h after anaesthesia. Results. The AMS and STAI scores were significantly better 90min after total i.v. anaesthesia compared with inhalation anaesthesia(P=0.02, P=0.05, respectively), but equal 24 h after both anaesthetictechniques (P=0.90, P=0.78, respectively); patient satisfactionwas comparable (P=0.26). Postoperative pain was comparable inboth groups 90 min and 24 h after anaesthesia (P=0.11, P=0.12,respectively). The incidence of postoperative nausea was reducedafter total i.v. compared with inhalation anaesthesia at 90min (7 vs 35%, P<0.001), and 24 h (33 vs 52%, P=0.001). Conclusion. Total i.v. anaesthesia improves early postoperativepatient well-being and reduces the incidence of PONV. Br J Anaesth 2003; 91: 631–7     

Constipation and its implications in the critically ill patient

Background. Motility of the lower gut has been little studiedin intensive care patients. Method. We prospectively studied constipation in an intensivecare unit of a university hospital, and conducted a nationalsurvey to assess the generalizability of our findings. Results. Constipation occurred in 83% of the patients. Moreconstipated patients (42.5%) failed to wean from mechanicalventilation than non-constipated patients (0%), P<0.05. Themedian length of stay in intensive care and the proportion ofpatients who failed to feed enterally were greater in constipatedthan non-constipated patients (10 vs 6.5 days and 27.5 vs 12.5%,respectively (NS)). The survey found similar observations inother units. Delays in weaning from mechanical ventilation andenteral feeding were reported by 28 and 48% of the units surveyed,respectively. Conclusions. Constipation has implications for the criticallyill. Br J Anaesth 2003; 91: 815–19     

Sequential compression device with thigh-high sleeves supports mean arterial pressure during Caesarean section under spinal anaesthesia

Background. This study investigated the use of a SequentialCompression Device (SCD) with thigh-high sleeves and a presetpressure of 50 mm Hg that recruits blood from the lower limbsintermittently, as a method to prevent spinal hypotension duringelective Caesarean section. Possible association of arterialpressure changes with maternal, fetal, haemodynamic, and anaestheticfactors were studied. Methods. Fifty healthy parturients undergoing elective Caesareansection under spinal anaesthesia were randomly assigned to eitherSCD (n=25) or control (n=25) groups. A standardized protocolfor pre-hydration and anaesthetic technique was followed. Hypotensionwas defined as a decrease in any mean arterial pressure (MAP)measurement by more than 20% of the baseline MAP. Systolic (SAP),MAP and diastolic (DAP) arterial pressure, pulse pressure (PP),and heart rate (HR) were noted at baseline and every minuteafter the spinal block until delivery. Results. A greater than 20% decrease in MAP occurred in 52%of patients in the SCD group vs 92% in the control group (P=0.004,odds ratio 0.094, 95% CI 0.018–0.488). There were no significantdifferences in SAP, DAP, HR, and PP between the groups. Conclusion. SCD use in conjunction with vasopressor significantlyreduced the incidence of a 20% reduction of MAP. Br J Anaesth 2003; 91: 695–8     

Predictive performance of computer-controlled infusion of remifentanil during propofol/remifentanil anaesthesia

Background. The predictive performance of the available pharmacokineticparameter sets for remifentanil, when used for target-controlledinfusion (TCI) during total i.v. anaesthesia, has not been determinedin a clinical setting. We studied the predictive performanceof five parameter sets of remifentanil when used for TCI ofremifentanil during propofol anaesthesia in surgical patients. Methods. Remifentanil concentration–time data that hadbeen collected during a previous pharmacodynamic interactionstudy in 30 female patients (ASA physical status I, aged 20–65 yr)who received a TCI of remifentanil and propofol during lowerabdominal surgery were used in this evaluation. The remifentanilconcentrations predicted by the five parameter sets were calculatedon the basis of the TCI device record of the infusion rate–timeprofile that had actually been administered to each individual.The individual and pooled bias [median performance error (MDPE)],inaccuracy [median absolute performance error (MDAPE)], divergenceand wobble of the remifentanil TCI device were determined fromthe pooled and intrasubject performance errors. Results. A total of 444 remifentanil blood samples were analysed.Blood propofol and remifentanil concentrations ranged from 0.5to 11 µg ml^–1 and 0.1 to 19.6 ng ml^–1respectively. Pooled MDPE and MDAPE of the remifentanil TCIdevice were –15 and 20% for the parameter set of Mintoand colleagues (Anesthesiology 1997; 86: 10–23), 1 and21%, –6 and 21%, and –6 and 19% for the three parametersets described by Egan and colleagues (Anesthesiology 1996;84: 821–33, Anesthesiology 1993; 79: 881–92, Anesthesiology1998; 89: 562–73), and –24 and 30% for the parameterset described by Drover and Lemmens (Anesthesiology 1998; 89:869–77). Conclusions. Remifentanil can be administered by TCI with acceptablebias and inaccuracy. The three pharmacokinetic parameter setsdescribed by Egan and colleagues resulted in the least biasand best accuracy. Br J Anaesth 2003; 90: 132–41     

Cerebral ischaemia during cardiac surgery in children detected by combined monitoring of BIS and near-infrared spectroscopy

Background. Children frequently suffer transient cerebral ischaemiaduring cardiac surgery. We measured cerebral ischaemia in childrenduring cardiac surgery by combining two methods of monitoring. Methods. We studied 65 children aged between 5 months and 17yr having surgery to correct non-cyanotic heart disease usinghypothermic cardiopulmonary bypass (CPB). During surgery, wemeasured the Bispectral Index (BIS) and regional cerebral haemoglobinoxygen saturation (Sr_O2) with near-infrared spectroscopy (NIRS).Cerebral ischaemia was diagnosed if both Sr_O2 and BIS decreasedabruptly when acute hypotension occurred. In each patient, therelationship between Sr_O2 and arterial blood pressure (AP) wasindicated by a plot of mean Sr_O2 against simultaneous mean AP. Results. We noted 72 episodes of cerebral ischaemia in 38 patients.Sixty-three ischaemic events were during CPB. Cerebral ischaemiawas less frequent in older patients. Cerebral ischaemia wasmore common and more frequent in children under 4 yr old. Haematocritduring CPB was lower and Sr_O2 was more dependent on AP in childrenunder 4 yr. Conclusions. Children less than 4 yr of age are more likelyto have cerebral ischaemia caused by hypotension during cardiacsurgery. Ineffective cerebral autoregulation and haemodilutionduring CPB may be responsible. Br J Anaesth 2004: 92: 662–9     

Effects of magnesium sulphate on cerebral haemodynamics in healthy volunteers: a transcranial Doppler study

Background. Magnesium is increasingly being considered as aneuroprotective agent. We aimed to study its effects on middlecerebral artery blood flow velocity (V_mca), cerebral autoregulationand cerebral vascular reactivity to carbon dioxide (CRCO₂) inhealthy volunteers. Methods. Fifteen healthy volunteers were recruited. Using transcranialDoppler ultrasonography, V_mca was recorded continuously. Thestrength of autoregulation was assessed by the transient hyperaemicresponse test, and the CRCO₂ was measured by assessing changesin V_mca to the induced changes in end-tidal carbon dioxide.I.V. infusion of magnesium sulphate was then started (loadingdose of 16 mmol followed by an infusion at the rate of 2.7 mmolh^–1) for 45 min. The cerebral haemodynamic variables weremeasured again near the end of the infusion of magnesium sulphate. Results. Total serum magnesium levels were doubled by the infusionregimen. However, there were no significant changes in V_mca,strength of autoregulation, or CRCO₂. Five of the volunteersreported marked nausea and two developed significant hypotensionduring the loading dose. Conclusions. Infusion of magnesium sulphate, in a dose thatdoubles its concentration in plasma, does not affect V_mca, strengthof autoregulation or CRCO₂ in healthy volunteers. However, itcan be associated with nausea and hypotension. Br J Anaesth 2003; 91: 273–5     

Pre-emptive lidocaine inhibits arterial vasoconstriction but not vasopressin release induced by a carbon dioxide pneumoperitoneum in pigs

Background. We assessed the preventive effects of i.v. or i.p.lidocaine administration on increases in vascular resistanceproduced by carbon dioxide pneumoperitoneum and related thisto vasopressin release. Methods. Carbon dioxide pneumoperitoneum (14 mm Hg intra-abdominalpressure) was performed in 32 anaesthetized young pigs and monitoredusing a pulmonary artery catheter. Animals received lidocaine0.5% (0.5 mg kg^–1) i.v. (n=9) or 2 ml kg^–1 i.p.(n=9) or saline (n=5) 15 min before the pneumoperitoneum andwere compared with a control group (n=9). Results. I.V. and i.p. lidocaine inhibited increases in meansystemic vascular resistance induced by the pneumoperitoneum[2109 (SD 935) and 2282 (895), respectively, vs 3013 (1067)dyne s^–1 cm^–5 in the control group]. Cardiac outputwas increased. Plasma lidocaine concentrations were threefoldhigher after i.p. administration than after i.v. administration.After pneumoperitoneum insufflation, plasma lysine-vasopressinconcentrations increased in all groups (control 74%, saline65%, i.p. lidocaine 57%, i.v. lidocaine 74%). Conclusions. I.V. and i.p. lidocaine blunted systemic vascularresponses to carbon dioxide pneumoperitoneum in pigs, but withoutinfluencing vasopressin release. Br J Anaesth 2003; 90: 343–8     

NICE guidelines for central venous catheterization in children. Is the evidence base sufficient?

Background. Recent guidelines from the National Institute forClinical Excellence (NICE) recommend the use of ultrasound guidancefor central venous catheterization in children. This study prospectivelyexamined the use of ultrasound guidance for central venous catheterizationin children undergoing heart surgery. Methods. One hundred and twenty-four infants and children wererandomized to either ultrasound-guided or traditional landmark-guidedcentral venous catheterization. Results. Success rates were significantly greater in the landmarkgroup compared with the ultrasound group (89.3% vs 78%, P<0.002),and arterial puncture rates were significantly lower in thelandmark group (6.2% vs 11.9%, P<0.03). There was no significantdifference between the two groups in the time taken to performthe catheterization. Conclusions. These results are different from the publishedresults on which the NICE guidelines were based; however, theevidence base in children is small. There is currently insufficientevidence to support the use of ultrasound guidance for centralvenous catheterization in children. Br J Anaesth 2004; 92: 827–30