Increased concentrations of L-lactate in the rectal lumen in patients undergoing cardiopulmonary bypass

Background. Gut ischaemia may contribute to morbidity in patientsafter cardiopulmonary bypass (CPB), but little is known aboutthe metabolic state of the large bowel in such patients. Thereforewe estimated the concentrations of L-lactate and in rectal mucosa in patients undergoing cardiac surgery withor without the use of CPB. Methods. Patients undergoing coronary artery bypass grafting(CABG) (n=12) or off-pump CABG (n=10) were subjected to equilibriumdialysis of the rectal lumen during the procedure and in thefirst 4 h afterwards. Dialysate concentrations of L-lactateand were measured using an auto-analyser and compared with values obtained in healthy subjects (n=10). Results. During CPB, a 2- to 3-fold increase in luminal concentrationsof L-lactate was observed (CABG vs off-pump CABG, P=0.05; CABGvs healthy subjects, P<0.01). The dialysate concentrationsof L-lactate were higher than the mean systemic values (luminal–arterialgradient mean (SD) 0.9 (1.0) mmol litre^–1, P<0.05),and the two values were positively correlated (P<0.05). LuminalL-lactate concentrations remained elevated 4 h after the operation.In contrast, dialysate was equally high in patient and control groups and substantially higher thanvalues observed in arterial blood. Conclusions. Uncomplicated CPB is associated with moderate butsustained increases in luminal concentrations of L-lactate inthe rectum, indicating metabolic dysfunction of the mucosa inthe large bowel. Part of this study was presented at the 27th Congress of theScandinavian Society of Anaesthesiology and Intensive Care Medicine,Helsinki, Finland, 2003.     

Haemodynamic and renal effects of intravenous enalaprilat during coronary artery bypass graft surgery in patients with ischaemic heart dysfunction

Renal dysfunction occurring after open heart surgery is multifactorialin origin but activation of the renin–angiotensin systemmay have a prominent role. Fourteen patients with ischaemicheart dysfunction scheduled for elective coronary artery bypassgraft (CABG) surgery were allocated to a treatment group [enalaprilatfor 2 days; ACEI (angiotensin-converting enzyme inhibitor) group,n=7] or a control group (n=7). The cardiac index was significantlyhigher in ACEI-treated patients than in the controls beforeand after cardiopulmonary bypass (CPB) (P<0.05) and on postoperativeday 2 (P<0.05). The systemic vascular resistance wassignificantly lower in the ACEI-treated patients than in thecontrols before and after CPB (P<0.05). Renal plasma flow,measured as [¹³¹I]orthoiodohippuran clearance (Cl_H), was higherin the ACEI group than in the control group before CPB, as wasendogenous creatinine clearance after CPB (P<0.05). On post-operativeday 7, Cl_H was significantly higher in the ACEI group thanin the control group (P<0.05). Plasma renin activity andvasopressin concentration increased in both groups during CPB(P<0.05). The study demonstrates that administration of ani.v. ACEI, enalaprilat, improves cardiac output during CABGsurgery in patients with ischaemic heart dysfunction. Moreover,renal perfusion was better maintained during surgery, and thiseffect was sustained up to post-operative day 7. Br J Anaesth 2001; 86: 169–75     

Effects of mid-line thoracotomy on the interaction between mechanical ventilation and cardiac filling during cardiac surgery

Background. Mid-line thoracotomy is a standard approach forcardiac surgery. However, little is known how this surgicalapproach affects the interaction between the circulation andmechanical ventilation. We studied how mid-line thoracotomyaffects cardiac filling volumes and cardiovascular haemodynamics,particularly variations in stroke volume and pulse pressurecaused by mechanical ventilation. Methods. We studied 19 patients during elective coronary arterybypass surgery. Before and after mid-line thoracotomy, we measuredarterial pressure, cardiac index (CI) and global end-diastolicvolume index (GEDVI) by thermodilution, left ventricular end-diastolicarea index (LVEDAI) by transoesophageal echocardiography andthe variations in left ventricular stroke volume and pulse pressureduring ventilation by arterial pulse contour analysis. Results. After thoracotomy, CI increased from 2.3 (0.4) to 2.9(0.6) litre min^–1 m^–2, GEDVI increased from 605(110) to 640 (94) litre min^–1 m^–2, and LVEDAI increasedfrom 9.2 (3.7) to 11.2 (4.1) cm² m^–2. All these changeswere significant. In contrast, stroke volume variation (SVV)decreased from 10 (3) to 6 (2)% and pulse pressure variation(PPV) decreased from 11 (3) to 5 (3)%. Before thoracotomy, SVVand PPV significantly correlated with GEDVI (both P<0.01).When the chest was open, similar significant correlations ofSVV (P<0.001) and PPV (P<0.01) were found with GEDVI. Conclusion. Thoracotomy increases cardiac filling and preload.Further, thoracotomy reduces the effect of mechanical ventilationon left ventricular stroke volume. However, also under openchest conditions, SVV and PPV are preload-dependent. Br J Anaesth 2004; 92: 808–13     

The effects of propofol on neutrophil function, lipid peroxidation and inflammatory response during elective coronary artery bypass grafting in patients with impaired ventricular function

Background. Coronary artery bypass grafting (CABG) with cardiopulmonarybypass elicits a potent reperfusion injury and inflammatoryresponse, more intense in patients with impaired myocardialfunction. Propofol has antioxidant properties which may attenuatesuch a response. Methods. In total, 27 patients with impaired left ventricularfunction undergoing CABG were randomly allocated to receiveeither target-controlled infusion propofol (P) or saline (S)immediately before aortic cross-clamp release until 4 h afterreperfusion. Troponin-I, Urinary 8-epi PGF-2 isoprostane, coronarysinus and systemic malondialdehyde concentrations, Interleukin-6(IL-6), -8 and -10 concentrations and leucocytes function studies(neutrophil respiratory burst, phagocytosis, CD-11b and CD-18expression) were measured. Results. Propofol decreased MDA coronary sinus concentrationat 1, 3 and 5 min after reperfusion (P<0.01); 60 min afterreperfusion a significant difference between the two groupsin systemic MDA concentrations was also seen. IL-6 concentrationincreases were significantly greater in Group S than Group P,4 h after reperfusion [1118 (1333) pg ml^–1 vs 228 (105)pg ml^–1, P<0.01]. Serum IL-8 concentrations did notincrease significantly in either group. Compared with baselinevalues IL-10 concentrations decreased after reperfusion butthe values were higher in the propofol group than in the controlgroup [22 (16) vs 11 (4) pg ml^–1, P<0.05]. No differencein leucocyte function or urinary isoprostane concentrationswas demonstrated. Conclusion. Propofol attenuates free-radical-mediated lipidperoxidation and systemic inflammation in patients with impairedmyocardial function undergoing CABG.     

Glucose,insulin and potassium for heart protection during cardiac surgery

Background. Coronary artery bypass grafting with hypothermiccardiac arrest and cardiopulmonary bypass (CPB) is associatedwith myocardial injury. Our study investigated whether an infusionof glucose, insulin and potassium (GIK) during elective coronaryartery bypass surgery decreases myocardial cell death. Methods. We measured cardiac troponin I (cTnI), a myofibrillarstructural protein, which is a sensitive and specific indicatorof myocytic injury. With ethics committee approval, 42 patientswere enrolled into a randomized, prospective, double-blindedstudy. In the GIK group, 500 ml of 50% dextrose solutioncontaining 100 IU insulin and potassium 80 mmol was infusedat the rate of 0.75 ml kg^–1 h^–1.Patients in the non-GIK group received 5% dextrose solutionat the same rate. Arterial blood samples were taken before inductionof anaesthesia, after removal of the aortic clamp and 6 and12 h after CPB. Results. In both groups there was an increase in cTnI concentration(P<0.05), which was greatest about 6 h after CPB. Atno time did the cTnI concentration differ between the two groups. Conclusion. The results suggest that GIK does not decrease theirreversible myocardial damage associated with routine coronaryartery bypass surgery. Br J Anaesth 2002; 88: 489–95     

Propofol attenuates myocardial lipid peroxidation during coronary artery bypass grafting surgery

Background. Propofol can scavenge free radicals because it hasa chemical structure similar to antioxidants. Methods. We examined if free radical scavenging occurs withpropofol during CABG operations. We studied 24 patients undergoingCABG surgery for triple vessel disease, randomized into twogroups. After induction of anaesthesia with fentanyl 10 µgkg^–1 and midazolam 0.1 mg kg^–1, patients in thefentanyl group (n=14) received fentanyl infusion 10–30µg kg^–1 h^–1 and patients in the propofol group(n=10) received propofol infusion 3–6 mg kg^–1 h^–1for maintenance of anaesthesia. Atrial tissue biopsies weretaken during cannulation for bypass, 45 min after cross-clampinsertion, 5 min after unclamping, and in the decannulationperiod. Lipid peroxidation was assessed by measurement of thiobarbituricacid reactive substances (TBARS) in the atrial tissue samples. Results. Lipid peroxidation in the propofol group was less thanin the fentanyl group (P<0.05) in all sampling periods. Lipidperoxidation in the fentanyl group increased significantly duringcardiopulmonary bypass (CPB) (P<0.05), but no increase wasfound in the propofol group (P>0.05). Conclusion. In clinical doses, propofol strongly attenuateslipid peroxidation during CABG surgery. Br J Anaesth 2002; 89: 242–6     

Dysaesthesia associated with sternotomy for heart surgery

Background. Chronic pain occurs in 40–50% patients followingcardiac surgery. Dysaesthesia, either in the form of heightenedor diminished skin sensation, are frequently associated withchronic neuropathic pain. Therefore, dysaesthesia in the earlypostoperative period may predict chronic pain. However, thecharacter and causes of dysaesthesia in the early postoperativeperiod are unknown. The aim of this study was to investigatethe incidence, extent, and causes of dysaesthesia followingcardiac surgery by sternotomy. Methods. In a prospective cohort study, 50 patients undergoingsternotomy for cardiac surgery were admitted to the study: 38underwent coronary artery bypass graft (CABG), nine valve surgery,and three combined surgery. Forty-eight hours postoperatively,acute pain was measured by four-point verbal scale. Manual pinprickand cotton wool brushing was used to detect the areas of dysaesthesia. Results. Some form of dysaesthesia was found in 27 (54%) ofthe patients. Using multivariate regression analysis, the totalarea of dysaesthesia was positively associated with CABG surgeryand the severity of postoperative pain (P<0.001). Conclusion. Dysaesthesia is common in the early postoperativeperiod following cardiac surgery using a sternotomy and is associatedwith CABG surgery. The association with severity of pain mayindicate a neuropathic element that is unrelieved by conventionalopioid analgesia.      

Ketamine for treatment of catheter related bladder discomfort: a prospective, randomized, placebo controlled and double blind study

Background. Intraoperative urinary catheterization might causepostoperative catheter related bladder discomfort (CRBD). Weevaluated the efficacy of ketamine as a treatment modality forCRBD. Methods. Fifty-four, ASA physical status I and II, male andfemale adult patients, having CRBD after elective percutaneousnephrolithotomy were randomized into two equal groups of 27each. In the postoperative period, patients who complained ofCRBD received medication depending upon group allocation. Group1 (Control) received placebo, Group II (Ketamine) received i.v.ketamine 250 µg kg^–1. After induction of anaesthesiapatients were catheterized with a 16 Fr Foley's catheter andthe balloon was inflated with 10 ml distilled water. Gradingof CRBD was done as none, mild, moderate and severe by a blindedobserver at 0, 1, 2 and 6 h after operation. Results. Ketamine reduced the incidence of CRBD (P<0.001)at 2 and 6 h along with reduction in severity (P<0.05) at1 h compared with control. Higher incidence of mild sedationwas observed in the ketamine group (P<0.05) which was notassociated with any untoward effects. Operative time and intraoperativefentanyl requirement were similar in both the groups. Conclusion. I.V. ketamine (250 µg kg^–1) is an effectivetreatment for reducing the incidence and severity of postoperativeCRBD.     

Genotype and interleukin-10 responses after cardiopulmonary bypass

Background. The pro- and anti-inflammatory cytokine balancehas been implicated in outcome from inflammatory conditions,and cardiopulmonary bypass is associated with a marked inflammatoryresponse. Interleukin-10 (IL-10) is an anti-inflammatory cytokineand levels have been shown to be highest in those patients whodevelop sepsis after trauma or surgery. IL-10 levels vary betweenindividuals and genotype may dictate the IL-10 response. Wetherefore investigated IL-10 genotype, circulating IL-10 concentrationsand outcome in terms of organ dysfunction 24 h after cardiopulmonarybypass. Methods. Blood samples were obtained from 150 patients before,and 3, and 24 h after cardiopulmonary bypass. IL-10 wasmeasured by enzyme immunoassay. The single nucleotide polymorphismat –1082 base pairs was detected by restriction fragmentlength polymorphism analysis. Post-bypass organ system dysfunctionwas defined prospectively. Results. IL-10 concentrations were increased 3 h afterbypass (P<0.0001) and were still increased at 24 h (P<0.0001).Homozygosity for the G allele was associated with lower median(range) maximal IL-10 levels at 3 h (44 (13–136)pg ml^–1) compared with the A allele (118 (39–472)pg ml^–1; P=0.042). Those patients who developed atleast one organ dysfunction (n=33) had higher IL-10 levels 3 hafter surgery (242 (18–694) pg ml^–1) comparedwith those without organ dysfunction (77 (7–586) pg ml^–1;P=0.001, n=117). Conclusions. The G allele of the –1082 base pair singlenucleotide polymorphism in the IL-10 gene is associated withlower IL-10 release after cardiopulmonary bypass. High levelsof IL-10 secretion are associated with organ dysfunction 24 hafter surgery. Br J Anaesth 2003; 91: 424–6     

Analgesic efficacy of rectal acetaminophen and ibuprofen alone or in combination for paediatric day-case adenoidectomy

Background. Acetaminophen and non-steroidal anti-inflammatorydrugs have different mechanisms of action. We investigated ifcombining rectal acetaminophen with ibuprofen would providebetter postoperative analgesia compared with either drug aloneafter adenoidectomy in children. Methods. 160 children, aged 1–6 yr, undergoing day-caseadenoidectomy, were randomized to receive either acetaminophen40 mg kg^–1, ibuprofen 15 mg kg^–1, their combination,or placebo rectally immediately after anaesthetic induction.A standard anaesthetic method was used and all children receivedalfentanil 10 µg kg^–1 i.v. during induction. Meperidine5–10 mg i.v. was used for rescue analgesia for a painscore (Objective Pain Scale) over 3. Recovery times, sedationscores and the need for rescue analgesia and adverse eventsduring the first 24 h after anaesthesia were recorded. Rescueanalgesic at home was ibuprofen 10 mg kg^–1. Results. Total meperidine requirements were significantly lessin the groups receiving acetaminophen, ibuprofen, or their combinationcompared with the group receiving placebo indicating an opioid-sparingeffect of 19–28% (P<0.05). Children given acetaminophenwere more sedated than those given ibuprofen (P<0.05). Dischargecriteria were fulfilled earlier in the ibuprofen group thanin all the other groups (P<0.05). At home, less children(49%) needed rescue analgesia in the combination group comparedwith the other groups (74–77%) (P<0.02). Conclusions. We conclude that prophylactically administeredrectal acetaminophen combined with ibuprofen does not improveanalgesia after adenoidectomy in the immediate postoperativeperiod compared with either drug alone but does decrease theneed for analgesia at home. Ibuprofen results in lesser sedationand faster discharge than when acetaminophen is used. Br J Anaesth 2003; 91: 363–7     

Effects of dexamethasone on clinical course,C-reactive protein,S100B protein and von Willebrand factor antigen after paediatric cardiac surgery

Background. Anti-inflammatory treatment with glucocorticoidsduring cardiopulmonary bypass can reduce inflammatory mediatorrelease, but the effects of glucocorticoid on outcome are controversial. Methods. We studied the effects of dexamethasone on clinicalcourse, C-reactive protein, von Willebrand factor antigen (vWf:Ag)and S100B in a randomized masked study of children after opencardiac surgery. Twenty children weighing >10 kg receiveddexamethasone (1 mg kg^–1) and 20 controls receivedsaline after induction of anaesthesia. We measured vWf:Ag asa marker of endothelial activation, S100B as a marker of cerebralprotein release and C-reactive protein as a marker of inflammatoryactivity. Oxygenation, body temperature, fluid balance, leucocyteand platelet counts, days in the intensive care unit (ICU) anddays on mechanical ventilation were noted. Results. Dexamethasone decreased C-reactive protein concentrationon the first postoperative day (P<0.05), but did not affectthe release of vWf:Ag or S100B. There was no significant differencein oxygenation, body temperature, fluid balance, leucocyte andplatelet counts, days in the ICU or days on mechanical ventilationbetween the placebo and dexamethasone-treated groups. Conclusion. Administration of dexamethasone before cardiopulmonarybypass for paediatric cardiac surgery decreased the inflammatoryresponse, but did not affect the immediate features after surgeryor changes in vWf:Ag or S100B. Br J Anaesth 2003; 90: 728–32     

Effects of prophylactic or therapeutic application of bovine haemoglobin HBOC-200 on ischaemia-reperfusion injury following acute coronary ligature in rats

Background. Haemoglobin-based oxygen carriers (HBOCs) are assessedas blood substitutes in patients with perioperative anaemiaincluding patients at risk for perioperative cardiac ischaemia.There is controversy as to whether HBOCs are beneficial or deleteriousduring ischaemia–reperfusion (I–R). Therefore theeffects of HBOC-200 on I–R injury were evaluated in arandomized placebo-controlled animal trial. Methods. Animals were randomized to receive either placebo i.v.without I–R (sham group, n=9), placebo i.v. with I–R(control group, n=10), HBOC-200 0.4 g kg^–1 i.v. priorto I–R (prophylaxis group, n=12) or HBOC-200 0.4 g kg^–1i.v. during I–R (therapy group, n=15). I–R consistedof 25 min of acute ligature of the left coronary artery followedby 120 min of reperfusion. Measurements included assessmentof the area at risk and infarct size using triphenyl tetrazoliumchloride (TTC) stain, DNA single-strand breaks (in situ nicktranslation with autoradiography/densitometry) and cardiac arrhythmias. Results. Infarct size within the area at risk was 62 (SD 15)%(control), 46 (10)% (prophylaxis, P<0.025 vs control) and61 (9)% (therapy, P<0.85 vs control). The frequency of DNAsingle-strand breaks was reduced vs control in the sham (P<0.01)and prophylaxis (P<0.04) groups and was almost the same inthe therapy group (P<0.75). The severity of cardiac arrhythmiasduring ischaemia was lower compared with control in the sham(P<0.001) and prophylaxis (P<0.039) groups, but therewas no difference in the therapy group. Conclusion. This study demonstrates that neither prophylacticnor therapeutic application of the cell-free haemoglobin solutionHBOC-200 aggravates cardiac I–R injury. Furthermore, theprophylactic approach may offer a new opportunity for pretreatmentof patients at risk for perioperative ischaemic cardiac events. The results were presented in part at the Congress of the EuropeanSociety of Anaesthesia, Glasgow, UK, June 2003 (‘BestAbstract Award’), and at the Annual Meeting of the AmericanSociety of Anesthesiologists, San Francisco, CA, USA, October2003. Declaration of interest. T. G. Standl has received lecture honorariaand travel fees from Biopure Corporation, Boston, MA, the manufacturerof HBOC. The Department of Anaesthesiology, University Hospital,Hamburg-Eppendorf, received restricted grants from Biopure Corporation,Boston, MA, between 1994 and 1998 for animal and clinical phaseII and III trials. M.A. Burmeister is Vice President Researchand Development, Hospital Care Division, B. Braun MelsungenAG, Melsungen, Germany. B. Braun, a global health care supplier,cooperated with Biopure Corporation, Boston, MA, on HBOC developmentuntil 1996. The work presented in this paper was done independentlyof and without any support from B. Braun.     

Lidocaine reduces ischaemic but not reperfusion injury in isolated rat heart

The local anaesthetic lidocaine protects the myocardium in ischaemia–reperfusionsituations. It is not known if this is the consequence of ananti-ischaemic effect or an effect on reperfusion injury. Therefore,we investigated the effect of two concentrations of lidocaineon myocardial ischaemia–reperfusion injury and on reperfusioninjury alone. We used an isolated rat heart model where heartrate, ventricular volume and coronary flow were kept constant.Hearts underwent 45 min of low-flow ischaemia followed by 90min reperfusion. Two groups received lidocaine 1.7 or 17 µgml^–1 starting 5 min before the onset of reperfusion. Intwo additional groups, lidocaine infusion started 5 min beforelow-flow ischaemia. In all groups, lidocaine administrationwas stopped after 15 min of reperfusion. One group served asan untreated control (n=11 in each group). Left ventriculardeveloped pressure (LVDP) and total creatine kinase release(CKR) were measured. Lidocaine administration during ischaemiaand reperfusion led to an improved recovery of LVDP during reperfusion(1.7 µg ml^–1, 54 (SEM 10) mm Hg; 17 µg ml^–1,71 (9) mm Hg at 30 min of reperfusion; both significantly differentfrom control (21 (4) mm Hg) (P<0.05)) and a reduced CKR (1.7µg ml^–1, 79 (13) IU; 17 µg ml^–1, 52(8) IU at 30 min of reperfusion; both significantly differentfrom control (130 (8) IU (P<0.05)). Lidocaine given duringearly reperfusion only, affected neither LVDP during reperfusion(1.7 µg ml^–1, 19 (6) mm Hg (P=1.0); 17 µgml^–1, 36 (8) mm Hg (P=0.46)) nor CKR (156 (21) IU (P=0.50)and 106 (14) IU (P=0.57)). We conclude that lidocaine protectsthe myocardium against ischaemic but not against reperfusioninjury in the isolated rat heart. Br J Anaesth 2001; 86: 846–52     

Effects of sevoflurane and propofol on left ventricular diastolic function in patients with pre-existing diastolic dysfunction

Background. The effects of anaesthetics on left ventricular(LV) diastolic function in patients with pre-existing diastolicdysfunction are not well known. We hypothesized that propofolbut not sevoflurane will worsen the pre-existing LV diastolicdysfunction. Methods. Of 24 randomized patients, 23 fulfilled the predefinedechocardiographic criterion for diastolic dysfunction. Theyreceived general anaesthesia with sevoflurane 1 MAC (n=12) orpropofol 4 µg ml^–1 (n=11). Echocardiographic examinationswere performed at baseline and in anaesthetized patients underspontaneous breathing and under positive pressure ventilation.Analysis focused on peak early diastolic velocity of the mitralannulus (E_a). Results. During spontaneous breathing, E_a was higher in thesevoflurane than in the propofol group [mean (95% CI) 7.0 (5.9–8.1)vs 5.5 (4.7–6.3) cm s^–1; P<0.05], reflectingan increase of E_a from baseline only in the sevoflurane group(P<0.01). Haemodynamic findings were similar in both groups,but the end-tidal carbon dioxide content was more elevated inthe propofol group (P<0.01). During positive pressure ventilation,E_a was similarly low in the sevoflurane and propofol groups[5.3 (4.2–6.3) and 4.4 (3.6–5.2) cm s^–1, respectively]. Conclusions. During spontaneous breathing, early diastolic functionimproved in the sevoflurane but not in the propofol group. However,during positive pressure ventilation and balanced anaesthesia,there was no evidence of different effects caused by the twoanaesthetics.     

Effect of lidocaine on ischaemic preconditioning in isolated rat heart

Background. Lidocaine is frequently used as an agent to treatventricular arrhythmias associated with acute myocardial ischaemia.Lidocaine is a potent blocker not only of sodium channels, butalso of ATP-sensitive potassium channels. The opening of thesechannels is a key mechanism of ischaemic preconditioning. Weinvestigated the hypothesis that lidocaine blocks the cardioprotectioninduced by ischaemic preconditioning. Methods. Isolated rat hearts (n=60) were subjected to 30 minof no-flow ischaemia and 60 min of reperfusion. Control hearts(CON) underwent no further intervention. Preconditioned hearts(PC) received two 5-min periods of ischaemia separated by 10min of reflow before the 30 min ischaemia. In three groups,lidocaine was infused at concentrations of 2, 10 or 20 µgml^–1 for 5 min before the preconditioning ischaemia. Leftventricular developed pressure (LVDP) and infarct size (IS)(triphenyltetrazolium choride staining) were measured as variablesof ventricular function and cellular injury, respectively. Results. PC reduced IS from 24.8 (SEM 4.1) % to 4.0 (0.7) %of the area at risk (P<0.05). Adding 2 or 10 µg ml^–1lidocaine had no effect on IS compared with PC alone (3.7 (0.7)%, 6.9 (1.8) %). Adding 20 µg ml^–1 lidocaine increasedIS to 14.1 (2.5) % compared with PC (P<0.05). Baseline LVDPwas similar in all groups (111.4 (2.1) mm Hg). Compared withCON, PC improved functional recovery (after 60 min of reperfusion;52.3 (5.9) mm Hg vs 16.0 (4.0) mm Hg, P<0.01). The improvedventricular function was not influenced by addition of 2 or10 µg ml^–1 lidocaine (47.3 (5.7) mm Hg, not significant;45.3 (7.3) mm Hg, not significant), but was blocked by the infusionof 20 µg ml^–1 lidocaine (22.5 (8.0) mm Hg, P<0.01vs PC). Conclusions. Lidocaine blocks the cardioprotection induced byischaemic preconditioning only at supratherapeutic concentrations.     

Cerebral embolization during cardiac surgery: impact of aortic atheroma burden

Background. Aortic atheromatous disease is known to be associatedwith an increased risk of perioperative stroke in the settingof cardiac surgery. In this study, we sought to determine therelationship between cerebral microemboli and aortic atheromaburden in patients undergoing cardiac surgery. Methods. Transoesophageal echocardiographic images of the ascending,arch and descending aorta were evaluated in 128 patients todetermine the aortic atheroma burden. Transcranial Doppler (TCD)of the right middle cerebral artery was performed in order tomeasure cerebral embolic load during surgery. Using multivariatelinear regression, the numbers of emboli were compared withthe atheroma burden. Results. After controlling for age, cardiopulmonary bypass timeand the number of bypass grafts, cerebral emboli were significantlyassociated with atheroma in the ascending aorta (R²=0.11, P=0.02)and aortic arch (P=0.013). However, there was no associationbetween emboli and descending aortic atheroma burden (R²=0.05,P=0.20). Conclusions. We demonstrate a positive relationship betweenTCD-detected cerebral emboli and the atheromatous burden ofthe ascending aorta and aortic arch. Previously demonstratedassociations between TCD-detectable cerebral emboli and adversecerebral outcome may be related to the presence of significantaortic atheromatous disease. Br J Anaesth 2003; 91: 656–61     

Utility of B-type natriuretic peptide in predicting perioperative cardiac events in patients undergoing major non-cardiac surgery

Background: B-type natriuretic peptide (BNP) levels predict cardiovascularrisk in several settings. We hypothesized that they would identifyindividuals at increased risk of early cardiac complicationsafter major non-cardiac surgery. The current study tests thishypothesis. Methods: Two hundred and four patients undergoing major non-cardiac surgerywere studied. The primary end-point was the development of acutemyocardial injury [defined as cardiac troponin I (cTnI) level> 0.32 ng ml^–1] or death in the 3 days after surgery. Results: Preoperative BNP levels were raised in patients who died orsuffered perioperative myocardial injury (median 52.2 vs 22.2pg ml^–1, P = 0.01) and BNP predicted this outcome withan area under the receiver operating characteristic curve of0.72 [95% confidence interval (CI) 0.59–0.86, P = 0.01].A preoperative BNP value > 40 pg ml^–1 was associatedwith an increased risk of death or perioperative myocardialinjury [odds ratio (OR) 6.8, 95% CI 1.8–25.9, P = 0.003],and remained independently predictive after correction for theRevised Cardiac Risk Index. Preoperative BNP levels were higherin patients who exhibited new onset atrial fibrillation or ST/T-wavechanges on their postoperative ECG (median 50.5 vs 22.5 pg litre^–1,P = 0.01). They were also higher in patients who had eitherelevation of cTnI > 0.32 ng ml^–1 or postoperative ECGabnormalities (median 50.4 vs 21.5 pg ml^–1, P < 0.001). Conclusions: In the setting of major non-cardiac surgery, preoperative BNPlevels are higher in patients who experience perioperative deathand myocardial injury. Larger studies are required to confirmthese data and to clarify what BNP levels may add to existingmethods of risk stratification.     

High concentrations of N-BNP are related to non-infectious severe SIRS associated with cardiovascular dysfunction occurring after off-pump coronary artery surgery

Background. Procalcitonin (PCT) blood concentrations are knownto be an appropriate marker of severe systemic inflammatoryresponse syndrome (SIRS) induced by coronary artery surgerywith and without cardiopulmonary bypass. Pro-brain natriureticpeptide (N-BNP) is a newly described cardiac hormone consideredto be an effective marker of severity and prognosis of acutecoronary syndromes and congestive heart failure. We evaluatedthe perioperative time courses of PCT and N-BNP and investigatedtheir role as early markers of severe SIRS (SIRS with cardiovasculardysfunction) induced by off-pump coronary artery bypass (OPCAB). Methods. Sixty-three patients were prospectively included. TheAmerican College of Chest Physicians Classification was usedto diagnose SIRS and organ system failure to define severe SIRS.Serum concentrations of PCT and N-BNP were determined before,during and after surgery. Receiver operating characteristiccurves and cut-off values were used to assess the ability ofthese markers to predict postoperative severe SIRS. Results. SIRS occurred in 25 (39%) patients. Nine of them (14%)showed severe SIRS. Significantly higher serum concentrationsof N-BNP and PCT were found in patients with severe SIRS withpeak concentrations respectively at 8887 pg ml^–1 (range2940–29372 pg ml^–1) for N-BNP and 9.50 ng ml^–1(range 1–65 ng ml^–1) for PCT. The area under thecurve using N-BNP to detect postoperative severe SIRS was 0.799before surgery (0.408 for PCT; P<0.01) and 0.824 at the endof surgery (0.762 for PCT; P<0.05). Conclusions. N-BNP may be an appropriate marker indicating theearly development of non-infectious postoperative severe SIRSafter OPCAB.      

Does the platelet function analyser (PFA-100) predict blood loss after cardiopulmonary bypass?

Background. This study was designed to determine if a new point-of-caretest (PFA-100^® platelet function analyser) that assessesplatelet function predicts blood loss after cardiac surgery. Methods and results. Blood samples from 70 patients were drawnbefore and after cardiopulmonary bypass (CPB) for PFA-100^®measurements. The system consists of a cartridge in which amembrane and an aperture are coated with either collagen/adenosine-5'-diphosphateor collagen/epinephrine. The instrument determines the timerequired for full occlusion of the aperture (closure time).We observed a weak correlation between pre-CPB collagen/epinephrineclosure time and second-hour mediastinal blood loss (r=0.34,P=0.01). The sensitivity and positive predictive value of thePFA-100^® measurements were comparable to platelet countfor predicting excessive bleeding after CPB (75 and 27% vs 100and 25%, respectively). Conclusions. The PFA-100^® is a logical test for detectingpatients who could have excessive bleeding after CPB. However,the PFA-100^® was not able to separate patients at low riskof subsequent bleeding from those who had substantial bleeding. Br J Anaesth 2003; 90: 692–3