Thrombin generation during cardiac bypass surgery E. Duff,1 V. Billing,1 D. McPherson1, M. Coakley1, P. Collins2 and JE. Hall1 1 Department of Anaesthetics, University Hospital of Wales, UK 2 Department of Haematology, University Hospital of Wales, UK Current concepts of haemostasis suggest that the amount of thrombin produced and the rate at which this occurs is the critical step in clot formation. Thrombin generation (TG) is measured by calibrated automated thrombography (CAT) activated by physiological concentrations of tissue factor in platelet rich (PRP) and poor (PPP) plasma. CAT may therefore be useful in predicting bleeding and be a better guide to blood product use. CAT establishes values for rate of TG, lag time to commence TG, peak thrombin level and endogenous thrombin potential (ETP), a measure of total thrombin produced. Methods Blood was taken from 26 patients at high risk of bleeding before and after cardiac bypass. TG was measured in PRP and PPP by CAT. Normal values were established from 30 healthy volunteers (HV). Wilcoxon* and Mann Whitney U** tests were used to analyse data. Results Table. Medians and inter-quartile ranges are shown. No significant difference was found between HVs and pre bypass samples. p1; HV vs post bypass, p2; pre vs post bypass. HV Pre bypass Post p1** p2* bypass PPP Lag 3.2 3.7 6.3 <0.0 =0.0 (mins) [2.8-3.8] [3.2-4.2] [5.1-7.6] 1 2 Peak 103 128 45 <0.0 =0.0 thrombin [81-133] [78-149] [11-74] 1 3 (nM) ETP 934 898 480 <0.0 =0.0 (nM/min) [793-1175] [728-1093 [169-639] 1 1 ] Rate TG 22.4 25.4 5.4 <0.0 =0.0 (nM/min) [15.4-26.0] [16.5-36.2 [1.5-9.8] 1 2 ] PRP Lag 32 26 35 =0.3 =0.0 (min) [27-36] [22-29] [25-51] 7 1 Peak 46 47 28 <0.0 <0.0 thrombin [40-60] [37-62] [22-31] 1 1 (nM) ETP 1244 1125 911 =0.0 <0.0 (nM/min) [1015-1419 [972-1344 [598-1113] 2 1 ] ] Rate TG 1.8 2.0 1.2 =0.0 =0.0 (nM/min) [1.5-2.3] [1.3-2.6] [0.8-2.3] 6 4 Discussion The data show that all parameters of TG are reduced postcardiac surgery in both PRP and PPP. It is possible that these assaysmay better predict bleeding than current standard assays andpotentially have a role in patient management. Studies are ongoing toestablish whether parameters of TG taken post cardiac bypass predictpost operative bleeding. References 1. Hemker HC et al. Calibrated automated thrombin generation measurement in clotting plasma. Pathophysiol Haemoss & Thromb 2003; 33: 4-15.
Problems in defining the incidence of post-operativeneurocognitive dysfunction after cardiac surgeryC. Cann1, A.R. Wilkes1, J.E. Hall1 and R.A. Kumar21 Department of Anaesthetics, Cardiff University, UK2 Department of Anaesthetics, University Hospital of Wales, Cardiff,UKPrevious work has sought to establish a link between blood markersand post-operative cognitive dysfunction (POCD) following cardiacsurgery . However, there is no gold standard technique employed todefine POCD, making it difficult to establish a link. This phenomenonhas led to a wide range of incidence of POCD being reported and thusthe estimation of a true incidence very difficult to ascertain. Twovariables that partially explain this are the application of differentstatistical rules and different batteries of neurocognitive tasks . Abattery of neurocognitive tasks is usually performed pre-operativelyand postoperatively and results compared. Batteries sometimesinclude the five tasks suggested by the statement of consensus onneurobehavioural assessment after cardiac surgery but not always, andmight include up to nine tasks altogether.The two most common forms of statistical tests used for statisticalanalysis are either the decline of more than one standard deviationfrom baseline task score on at least 20% of the tasks or the decline intask scores by at least 20% from baseline on at least 20% of tasks .Although much work has been carried out investigating the role ofblood markers in predicting POCD it is perhaps more useful toreassess the definition of POCD before examining blood markersfurther.MethodsUsing data relating to the difference found between day five and pre-operative task results from Kumar et al’s study  we performed bothof the above statistical tests on firstly just the five core neurocognitivetasks and secondly on the total battery of nine tasks used in this dataset.ResultsTable 1: Patients with POCD following 1SD and 20% test. Dataexpressed as numbers (%). No of patients with POCD (n=31)Battery 1SD test 20% test5 tasks 11(35%) 21 (68%)9 tasks 8 (26%) 18 (58%)DiscussionThe incidence of POCD reported varies depending on which battery ofneurocognitive tasks is chosen and also which statistical tests areutilised. Although a wide range is demonstrated it would perhaps bebetter to have a smaller range defining POCD. Further work includingexploration of the sensitivity and specificity of particular tests isrequired in order to ascertain how one should define POCD.Following on from this the role of blood markers may be explored.References1 Kumar R A, Cann C, Hall J E, Sudheer P S and Wilkes AR. Br. J.Anaesth 2007; 98: 317-322.2 Lewis M S, Maruff P, Silbert B S, Evered L A, Scott D A. ActaAnaesthesiol Scand 2006; 50: 50-57.3 Alston R P, Kumar R A, Cann C, Hall J, Sudheer P, and Wilkes A.Br. J. Anaesth 2007; 99: 444-445.
The impact of computerised physician order entry on prescribingpractices in cardiothoracic ICUJ. Ali1, L. Barrow2a and A. Vuylsteke2b1 Clinical School, University of Cambridge 2 Department of Pharmacya and Anaesthesia and Intensive Careb,Papworth Hospital, Cambridge, UKMuch attention has focused upon medication errors and the associatedpatient safety. Medication errors are more prevalent in ICU’s1; andmight even be higher in cardiothoracic units due to the large numberof medications prescribed and the rapid turnover of patients.Legibility and completeness of orders is one area where errors occurduring the prescribing phase. This study compares the quality,including completeness and legibility, of handwritten medicationorders versus computerised physician order entry (CPOE) in acardiothoracic ICU, as well as quality of the audit trail in relation toadministration.MethodsThis study is a prospective time series cross sectional audit, conductedin three phases, each involving the auditing of every prescription forevery patient in the ICU for two consecutive weeks at 7 months pre-implementation and at 5 and 11 months post implementation of aclinical information system. Descriptive statistics were applied to thedata collected.Results14,721 prescription orders were analysed, representing 613 patientsover the 6 weeks of study over the three periods. The CPOE systemeliminated all issues of legibility and completeness due to the natureof electronic prescribing (figure 1). Previously, for example, only 31%of signatures were legible, thus hindering traceability. A small fall incompletion of the intra-operative information was initially observed(97.3% to 92.6%) but this had risen to 99% by the end of the study.There was a change in proportion of drug prescribed in favour of‘regular’ prescriptions, rising from 61% to 80% of all prescriptions.While not an objective of the study, it was noted that the averagepharmacy cost per patient has fallen from £100.16 to £76.74 perpatient after introduction of CPOE, irrespective of bed occupancy. Pre Post-1 Post-2No dose written 11.7 0 0No route indicated 8 0 0No time to be given stated 25.2 0 0Non-generic drug name used 20.1 0 0Signature legible 31.6 100 100Allergy box completed 93.7 83.8 99Table 1 Percentage completion of various parameters for ‘STAT’prescription orders and allergy notification.DiscussionCPOE implementation has dramatically improved the quality,including completeness and legibility, of prescription and record ofadministration. The medication process is being made safer, withmore complete information. At the same time, in line with theliterature, drug costs have been reduced. This demonstrates that thereis a significant gain by implementing CPOE throughout allcardiothoracic ICU’s.References1 Ridley SA, Booth SA, Thompson CM, the Intensive Care Society’sWorking Group on Adverse Incidents. Prescription errors in UK
critical care units. Anesthesia 2004; 54:1193-1200
Rate of change of clot flexibility during cardiac bypass surgeryE. Duff,1 V. Billing,1 D. McPherson1, M. Coakley1, P. Collins2and JE. Hall11 Department of Anaesthetics, University Hospital of Wales, UK2 Department of Haematology, University Hospital of Wales, UKRoutine coagulation tests are poorly predictive of bleeding becausethey are activated in non-physiological ways and do not measurethe rate of clot formation (CF), an important aspect of in vivohaemostasis . Tests that are activated by physiologicalconcentrations of tissue factor (TF) and measure the rate of CF,may better predict bleeding and be useful to guide blood productsusage.Methods26 patients undergoing cardiac bypass and at high risk of bleedingwere recruited. Whole blood samples pre and post bypass wereassayed using standard and novel tests of CF. The novel tests werethromboelastometry (ROTEM) using a physiological concentrationof TF with contact activation inhibited and clot flexibility datamathematically manipluated to calculate the maximum velocity(Vmax) and time to Vmax (TVmax) of CF. Normal values wereestablished on 30 healthy volunteers (HV). Data were analysedwith Wilcoxon* and Mann Whitney**.ResultsTable. Results shown are median and inter-quartile ranges in HVs,pre and post bypass. No significant difference was shown betweenHVs and pre bypass. p1; HV vs post bypass, p2; pre vs post bypass. HV Pre bypass Post bypass p1** p2* PT 11.8 12.8 16.6 <0.01 <0.01 (s) [11.5-12.3] [12.3-13.4] [15.8-18.0] APTT 30 32 66 <0.01 <0.01 (s) [28-32] [28-35] [57-75] Fib 2.97 3.47 1.51 <0.01 <0.01 (g/l) [2.32-3.4] [3.1-4.1] [1.3-1.9] Plt×109/ 251 200 89.5 <0.01 <0.01 L [236-292] [165-237] [66-131] CT ND 161 221 NA <0.01 (s) [142-182] [184-294] CFT ND 64 169 NA <0.01 (s) [58-77] [126-192] MCF ND 61 45 NA <0.01 (s) [58-65] [8-48] Αlpha ND 77 63 NA <0.01 (o) [75-78] [58-66] Vmax 14 15.5 9 <0.01 =0.01 (mm/s) [13-15] [14.0-18.8] [7.5-10] TVmax 255 255 335 <0.01 =0.02 (s) [230-268] [233-292] [282-374]Fib(fibrinogen), plt(platelets), CT(clot time), CFT(clot formationtime), MCF(maximum clot firmness).DiscussionThese data demonstrate that post cardiac bypass the maxium rate ofclot formation is reduced and delayed. Further studies areunderway to establish whether the measurement of the rate of clotfomration is more useful than standard assays in predicting postoperative bleeding endpoints.References1 Sorensen B et al. Whole blood coagulation thromboelastographic profiles employing minimal tissue factor activation. J Thrombs Haemost 2003; 1-8: 551-8.
Aprotinin and long-term mortality after primary coronary arterybypass graft surgeryA. Roscoe,1 J. Barker1 and B. Bridgewater21 Department of Anaesthesia, Wythenshawe Hospital, Manchester,UK2 Department of Cardiothoracic Surgery, Wythenshawe Hospital,Manchester, UKThe use of antifibrinolytics, including aprotinin and tranexamic acid(TA) has been shown to reduce bleeding after cardiac surgery .Recent research has suggested that the use of aprotinin in primarycoronary artery bypass graft (CABG) surgery is associated with anincrease in long-term mortality . We performed a retrospectivereview of patients who underwent primary CABG surgery to establishlong-term mortality with respect to the antifibrinolytic used.MethodsFollowing local Research and Ethics Committee approval, the recordsof all patients who underwent primary CABG surgery from April 1st2002 to March 31st 2003 were reviewed. Patients’ demographic datawere recorded. Patients were divided into two groups by theantifibrinolytic they received: aprotinin or TA. Four-year mortalitywas established by accessing the Office of National Statistics trackingsystem for all-cause mortality. An unpaired t-test was used to comparethe difference between the means of the two groups. Fishers exact testwas used to compare the difference in mortality between the twogroups. Parametric data are displayed as mean (standard deviation).ResultsDuring the period of review, 719 patients underwent primary CABG.Demographic data and EuroScore were similar between the twogroups. There were 615 patients in the aprotinin group, of which 74%were male, with a mean age of 65 (9) years and mean EuroScore of2.9 (2.3). There were 104 patients in the TA group, of which 78%were male, with a mean age of 68 (10) years and mean EuroScore of3.4 (2.4). Overall 4-year mortality was 9.9%. The 4-year mortalitywas 9.9% in the aprotinin group and 9.6% in the TA group (p = 0.55).DiscussionIn our institution, aprotinin is used almost exclusively as theantifibrinolytic for patients undergoing primary CABG surgery.Mangano et al showed that long-term mortality was increased inCABG patients receiving aprotinin , with a 4-year mortality ofapproximately 14%, rising to 20% at 5 years. In our institution, wehave shown no difference in 4-year mortality between patients whoreceived aprotinin and TA. Although there was insufficient data toperform propensity score matching of patients, this study suggeststhat, in our institution, the use of aprotinin in primary CABG surgeryis not associated with an increase in 4-year mortality.AcknowledgementsNoneReferences1 Mongan PD, Brown RS, Thwaites BK. Tranexamic acid andaprotinin reduce postoperative bleeding and transfusions duringprimary coronary revascularization. Anesth Analg 1998; 87: 258-65.2 Mangano DT, Miao Y, Vuylsteke A et al. Mortality associated withaprotinin during 5 years following coronary artery bypass graftsurgery. JAMA 2007; 297: 471-9.
Successful extra corporeal membrane oxygenation (ECMO)support after Pulmonary Thromboendarterectomy (PTE)A. Snell1, A. Klein1, A. Vuylsteke1, R. Hall1, J. Arrowsmith1, JKneeshaw1, M. Berman2, S. Tsui2 and D.P. Jenkins21 Department of Anaesthesia, Papworth Hospital, UK2 Department of cardiothoracic surgery, Papworth Hospital UKPTE is the treatment of choice for patients with chronicthromboembolic pulmonary hypertension. However, some patientsdevelop severe cardio-respiratory compromise immediately afterweaning from cardiopulmonary bypass; this may follow earlyreperfusion pulmonary oedema or right ventricular failure secondaryto distal vascular obstructions not cleared by surgery.MethodsVeno- arterial ECMO for these severely compromised patients hasrecently been introduced. We performed a retrospective review of allpatients undergoing PTE from Aug 2005 to Aug 2007 at the UKnational center to examine the impact of ECMO.Results127 consecutive patients underwent PTE surgery. Seven patients(5.5%) had extreme cardio-respiratory compromise in the immediatepost-operative period and required ECMO, of which 4/7 (57%)survived to leave hospital. Their mean age was 51.3 years with 4males. The ECMO group had significantly poorer haemodynamicdata recorded before surgery:Table 1: Haemodynamic data for patients undergoing PTE, before andafter surgery ECMO No P n=7 ECMO value n=120survivors 4 (57%) 115 <0.0 (96%) 1mean PA (mmHg) before PTE 61.7 50.5 0.02mean PA (mmHg) after PTE 39.0 26.1 <0.01PVR (dynes/sec/cm-5) before 896 708 0.10PTEPVR (dynes/sec/cm-5) after PTE 479 273 <0.01CI (L/min/1.73m2) before PTE 2.7 2.7 0.91CI (L/min/1.73m2) after PTE 2.6 2.9 0.42The primary indications for instituting ECMO were residual severepulmonary hypertension (4), severe derangement in gas exchange (2)and very low cardiac output (1). In 5 patients cardio-respiratory arresthad occurred and resuscitation was required until ECMO had beencommenced. Mean duration of support was 119 hours (49-359 hours).Five patients were successfully weaned and 4 left hospital alive givinga survival rate of 57%. For those who did not require ECMO support,hospital mortality was 4.2%.DiscussionECMO is beneficial as a salvage therapy in patients sufferingcardiovascular collapse following PTE surgery. The success of ECMOin this situation in adult patients is higher than expected.
Cardiac Anaesthesia Simulation Training (CAST) in SheffieldA. Parnell1, P. Bedford2, R.Jutley3 and S. Kurian11 Department of Anaesthesia & Critical Care, Northern GeneralHospital, Sheffield, UK2 Senior Faculty, Montagu Clinical Simulation Centre, Mexborough,3 Department of Cardiothoracic Surgery, NGH, Sheffield, UKThe use of medical simulators has become a widespread method ofteaching and training in recent years, especially in the field ofanaesthesia . High-fidelity medical simulators are educationallyeffective and simulation-based education complements medicaleducation in patient care settings . The Royal College ofAnaesthetists recommend that specific competencies in cardiacanaesthesia are gained at ST 3/4 (formerly SpR 1/2) level . Fewcardiac units in the UK allow anaesthetic trainees to undertake sololists , therefore a trainee may complete a module in cardiacanaesthesia without dealing with common peri-operative problems. InSheffield we have set up a Cardiac Anaesthesia Simulation Training(CAST) course specifically for anaesthetic trainees. We are not awareof any other cardiac anaesthesia simulation courses in the UK.MethodThe course concentrates on teaching using a hardware-based, scriptedsimulation of a routine coronary artery bypass operation. Facilities atthe Montagu Simulation Centre (Mexborough Hospital, SouthYorkshire) comprise a control room and simulation room containing ahigh fidelity human patient simulator and fully functional anaestheticmachine. A cardiopulmonary bypass machine has been acquired toimprove the reality of the simulation. The scripted scenarios reproducethe pharmacological and physiological effects of anaesthesia andsurgery in real time. The trainee must manage the patient and interactwith the surgical team as they would for a real case.ResultsFour CAST courses have been run so far. Sixteen trainees have takenpart in the course. Feedback questionnaires revealed that 88% feltbetter able to manage problems in the future and 88% believed thetraining will improve patient safety. All candidates found the coursewas relevant, the debriefing was constructive and all wouldrecommend the course to their colleagues.DiscussionThe development of a Cardiac Anaesthesia Simulation Trainingcourse in Sheffield is the first in the UK and is a beneficial teachingtool. We shall continue to provide the course to improve knowledgeand confidence, whilst assisting in fulfilling competency requirementsset out by the Royal College of Anaesthetists.References1. Sinz E. Simulation-based education for cardiac, thoracic, andvascular anesthesiology. Semin Cardiothorac Vasc Anesth. 2005; 9:291-307.2. Issenberg SB, McGaghie WC, Petrusa ER, Gordon DL, Scalese RJ.Features and uses of high-fidelity medical simulations that lead toeffective learning: a BEME systematic review. Medical Teacher 2005;27: 10-28.3. Royal College of Anaesthetists: The CCT in Anaesthesia III:Competency Based Intermediate level ST Years 3 and 4, Training andAssessment. http://rcoa.ac.uk/docs/CCTptiii4. Morgan J. Trainees solo cardiothoracic lists survey, Feb 2007.Personal communication.
Use of anticoagulation in patients with Heparin InducedThrombocytopeniaL. Srinivasa, S. Karthikeyan, and D. PlaceDepartment of Anaesthetics, University Hospital of Wales, UKHeparin induced thrombocytopenia is an infrequent but importantcomplication seen in cardiac surgical patients. The risk of thrombosisand adverse outcome, if untreated, is well known. A number ofalternative anticoagulants to heparin are available and there is agrowing, but largely anecdotal, evidence base for the use of theseagents. We have made an attempt to identify the current UK practicesin the management of this condition.MethodsA written questionnaire was sent to all the ACTA linkmen in the UKasking for practices and guidelines in the management of heparininduced thrombocytopenia in adult cardiac surgical patients. Overallresponse rate was 47%.ResultsAlthough a third of the units have operated on confirmed HIT patients,72% of units have encountered them post-operatively. There is areported increase in the number of HIT patients in units using heparinflush in their pressure monitoring system. Lepirudin is the mostpopular anticoagulant used intraoperatively. Aspirin and danaparoidhave been used solely or in combination postoperatively. A variety ofagents were in use for patients requiring haemofiltration with 45% ofunits using epoprostenol and 38% danaparoid.Figure 1 Postoperative anticoagulation used in HIT patients 9 8 7 6 Aspirin 5 Clopidogrel Lepuridin Danaparoid Argatroban 4 Others None 3 2 1 0 Valve surgery CABG DVT prophylaxisDiscussionThe choice of alternative anticoagulation agents has been varied.There appears to be a lack of protocols/guidelines being used in themanagement of such patients with only less than 30% units havingthem. The Haemostasis and Thrombosis Task Force of the BritishCommittee for standards in haematology have produced guidelines formanagement of HIT.1 more work needs to be done to look into thecorrelation between heparin flush system and HIT.References1 Keeling D, Davidson S, Watson H. The management of heparininduced thrombocytopenia. Br J Haematology 2006; 133: 259-69
Survey of glycaemic control protocols in cardiac surgical intensivecare unitV. S. Badge, G. Govindarajan and F. M. AshiqDeparment of Cardiothoracic Anaesthesia, Essex CardiothoracicCentre, Basildon & Thurrock University Hospital, UKIntroductionHyperglycaemia is common in patients undergoing cardiac surgeryeven when glucose homeostasis has been normal in the preoperativeperiod1-3. Morbidity and mortality has been shown to be reduced inthese patients following tight control of blood glucose levels usinginsulin therapy3.MethodsIn our survey, we collected data telephonically from Sister-in chargeand ICU registrar of 36 Cardiac Surgical Intensive Care Units in theUnited Kingdom. The important parameters included were types andnumber of cases, range of sugar levels in ICU patients, insulinprotocol for control of sugar, maintenance fluid and range of K+.ResultsIt was observed that blood glucose is maintained below 10mmol/l.However, there was variation in the treatment as per insulin protocol,use of maintenance fluid and also the range of K+ level in ICU.DiscussionThe in-hospital morbidity and mortality is reduced by strictmaintenance of normoglycaemia4. The tight control of blood glucoserather than higher insulin dose appears to protect against most ICUcomplications and death3. Although all the centres had protocol forsugar control, there were wide variations in insulin protocols.References 1. Van Den Berghe G et al. Intensive insulin therapy in the surgical intensive care unit. N Engl J Med 2001; 354: 1417-1418. 2. Finney J et al. Glucose control and mortality in critically ill patients. J Am Med Assoc 2003; 290(15):2041-2047. 3. Van den Berghe G et al. Outcome benefit of intensive insulin therapy in the critically ill: insulin dose versus glycemic control. CCM 2003; Vol 31, No2. 4. Van den Berghe G et al. Intensive insulin therapy in critically ill patients. N Engl J Med 2001; 345:1359-1369
Perioperative renal function pattern during cardiac surgeryA.Pai1, U.Puar1, and A.Gaur11 Department of Anaesthesia, Glenfield Hospital, Leicester UKMethodsWe performed an audit on 126 consecutive adult patients listed forelective cardiac surgery during a six week period. Blood urea, serumcreatinine and eGFR values were recorded in the perioperative perioduntil 96 hours postoperatively. Intraoperative data included use anddosage of antifibrinolytics if any (aprotinin and tranexemic acid).Blood loss was recorded for the first 8 hours of the postoperativeperiod. We also recorded the incidence of re explorations,haemofiltration and stroke (definitive paresis or paralysis) in the postoperative period up to 24 hours. Risk of renal injury was suspectedwhen the creatinine levels increased by 1.5 times and a fall in eGFRby 25% or more than the baseline .ResultsPrimary cardiac surgery was performed on 115 patients and theremaining 11 underwent redo surgery. 32 (25.3%) patients did notreceive any antifibrinolytic (NAF), 83 (65.8%) received aprotinin(AP) which included 12 patients who also received tranexemic acid(TXA). 11 (18.2%) received tranexemic acid. Patients received varieddoses of aprotinin. 32 (38.5%) received 1 mKIU (million kallikrieninactivator units), 35 (42.1%) received 2mKIU and the rest 16(19.4%) received 3, 4 or 6mKIU; infusion of AP was not given.Dosage of TXA varied from 1-3gms, 87% receiving 2gms. Blood lossin the first 8 hours of post operative period was reduced in both theAP and TXA group with 9.3% incidence of re- exploration in NAFgroup versus 3.6% in AP and 0% in TXA group. Overall risk of renalinjury (Figure 1) was increased by 24.6%, 12.5% in NAF group,28.9% in AP group and 27.2% in TXA group. One patient whoreceived aprotinin required haemofiltration; no incidence of strokewas reported in any.Figure 1: Risk of renal injury in the postoperative period NAF 12.5% TXA 27.2% AP 28.9% Overall 24.6%DiscussionIncidence of renal dysfunction in our hospital is comparable to thosereported in the literature. Our results show a possible association ofrenal dysfunction with aprotinin  and interestingly, tranexemic acidtoo. Both agents appear to be effective in reducing blood loss.References1 Bellomo R, Claudio R et al. Acute renal failure – definition,outcome measures, animal models, fluid therapy and informationtechnology needs: the Second International Consensus Conference ofthe Acute Dialysis Quality Initiative (ADQI) Group. Crit Care 2004,8:R204-R2122 Mangano DT, Tudor J et al. The Risk Associated with Aprotinin inCardiac Surgery. N Engl J Med 2006; 354:353-65
A postal survey of current UK cardiac anaesthetic haemostaticpractice.G. Sundaram1, S. Hussin1, S.H. Pennefather11 Department of Anaesthesia, Cardiothoracic Centre – Liverpool, UKThere is a surprising lack of clear evidence to guide clinical practice inthis field. The present controversy surrounding the use of aprotoninhas highlighted variations in clinical practice. Prior to undertakingresearch in this area we wished to document current UK practice.MethodIn June 2007 we sent a postal survey to all consultant anaestheticmembers of ACTA. Of the 322 questionnaires sent, 4 were returnedundelivered. The 158 (50%) completed questionnaires form the basisof this report.ResultsMost (74%) of respondents administer 101 to 300 cardiac anaestheticsper year. Intraoperative cell salvage was routinely used by 65% ofrespondents.For on-pump surgery 98% of respondents used a target ACT ≥400 s.An initial loading of ≥300 unit kg-1 heparin was used by 99%. Forelective first time CABG aprotonin was used routinely by 23% andtranexamic acid by 60% of respondents. For elective valvereplacement aprotonin was used routinely be 34% and tranexamic acidby 46%, of respondents. For Jehovah Witness undergoing electiveCABG aprotonin was used routinely by 66% and tranexamic acid by34% of respondents. For endocarditis requiring urgent valvereplacement aprotonin was used routinely by 87% and tranexamicacid by 16% of respondents.For off pump surgery the target ACT was variable, 32% ofrespondents used an ACT of ≥400 s whilst 21% used an ACT of <300s. The initial loading dose of heparin was similarly variable, 31% ofrespondents used an initial loading dose of ≥300 units kg -1 of heparin.For first time OPCAB surgery 8% of respondents routinely useaprotonin whilst 53% never use aprotonin for this indication.Tranexamic acid is routinely used for first time OPCAB surgery by51% of respondents.Aprotonin. 65% of respondents use the Hammersmith regime.Tranexamic acid. A loading dose was administered by 91% ofrespondents. The loading dose varies from 0.5 to ≥3g but only 19%follow this by an infusion. A bolus is administration into the bypasscircuit by 17%.Heparin reversal. Assuming initial and final ACT to be similar 42%of respondents administer <1mg of protamine for each initial 100 U ofheparin and 50% administer 1 to 1.2 mg of protamine for each initial100 U of heparin. 93% would document the ACT immediately afterprotamine, 73% of respondents would re-measure the ACT if bleedingwas excessive. Further protamine to prevent rebound heparinizationwas given routinely by 7% of respondents usually as an infusion.TEG is routinely available to 78% of respondents and routinely usedby 26%. When TEG is used electively 66% of anaesthetists wouldobtain a baseline measurement and 90% would obtain a post-protamine TEGDiscussionThis survey highlights areas without consensus including: target ACTfor OPCAB surgery, use of antifibrinoltytic drugs for OPCABsurgery, choice of antifibrinolytic agent for on pump surgery, optimaldosage of tranexamic acid and aspects of heparin reversal. There islittle published evidence to guide management in most of these areas.Clinical studies in these areas would be helpful in providingguidelines.
Use of monitoring devices and alarms during anaesthesia for cardiacsurgery: a survey of practices at NHS Hospitals within the UnitedKingdomV. Tarnal, S. Shenoy and S. KarthikeyanDepartment of Anaesthetics, University Hospital of Wales, Cardiff,UKImprovements in patient safety result from the routine use ofmonitoring equipment during general anaesthesia. The AAGBI haveissued recommendations for minimal standard of monitoring duringanaesthesia and suggested additional modifications to cover otherareas of practice like Cardiac Surgery . The ACTA in conjunctionwith other Societies came up with the recommendations for standardof monitoring and alarms during cardiopulmonary bypass (CPB) .The aim of this survey was to evaluate the use of monitoring devicesand alarms before, during and after CPB.MethodA mail questionnaire was sent to the ACTA Linkmen at 48 NHShospitals within the UK. The questionnaire sought information aboutroutine use of monitoring devices and also the practice of settingalarms before, during and after CPB.ResultsThe response rate was 81% (39 / 48). Cardiac anaesthesia was nolonger practiced in three of the 39 centres. All the centres met theminimum standard monitoring recommended by the Associationduring general Anaesthesia. There was wide variation in the use ofmonitoring relevant to Cardiac Anaesthesia (Table 1). pH PO2 PCO2 OximetryContinuous Arterial 21 (58%) 24 (67%) 21 (58%) 25 (70%)Intermittent Arterial 34 (94%) 34 (94%) 34 (94%) 33 (94%)Mixed Venous 4 (10%) 8 (22%) 3 (8%) 23 (64%)Table 1Only 19% of the centres monitored awareness pre CPB and 8% postCPB. TOE was routinely monitored in 42% of the centres. There wasalso a wide variation in the alarm settings before, during and post CPBbetween the centres.DiscussionOur Survey found out that there has been a definite improvement ascompared to the previous survey  in the use of monitors duringanaesthesia as recommended for cardiac surgery (100% vs. 76%). Wefound that there was a wide variation in the use of alarms duringCardiac Surgery. Most centres have the alarms on during Pre and PostBypass (89%), but not during bypass (<25%). This raises theinteresting question whether there should be a standardrecommendation for the use of Alarms during CPB.References 1. AAGBI 2007; www.aagbi.org 2. ACTA 2007; www.acta.org.uk 3. S. Cockroft. J. Cardiothorac.Vasc.Anesth 1994; Aug 8(4):382-5
Experience of continuous ventricular support with Levitronixdevice – a retrospective reviewS. Woods1, A Klein2 and S Tsui3.1 Cambridge Perfusion Services, Papworth Hospital, UK2 Department of Anaesthesia, Papworth Hospital, UK3 Department of Cardiothoracic Surgery, Papworth Hospital, UKA retrospective review was conducted to examine survival in patientswith life-threatening cardiac failure requiring mechanical support,following the introduction of a new continuous device.MethodsCase-notes of all patients receiving Levitronix ventricular assistdevice (VAD) between July 2004 and July 2007 (3 year period) werestudied.Results31 patients were included. 3/31 patients were transplanted, 8/31 weresuccessfully weaned from support, and in total 10 patients survived toleave hospital. There were no incidents of pump thrombosis ormalfunction.Table 1. Demographic data Mean Femal Mean Mean Mean age - e duration ICU hospital years Sex of stay stay (%age) support (days) (days) (days) Survivors 45.2 3 10 35 58 n=11 (27%) Non-survivors 50.7 7 15 12 21 n=20 (35%)Indications for VAD support were heart failure (10/31, 18% survival),post-cardiotomy (10/31, 46% survival), post-heart transplant (9/31,27% survival) and post-MI (2/31, 9% survival).DiscussionTemporary VAD support is often the only method of supporting thefailing heart, when the patient is considered too unwell to survive anyother intervention. The survival rate of 10/31 (32%) is thereforesignificant as without support these patients would be expected to dieimminently.The results demonstrate improved survival in patients with post-cardiotomy cardiac failure compared to long-standing heart failure;this is not surprising as the latter group are likely to have chronicmulti-organ dysfunction, poor nutrition and muscle wasting.The Levitronix device is a non-contact continuous flow pump,designed to have a low rate of heamolysis and thrombogenicity. It isrecommended for up to 30 days use, and data has shown excellentreliability within this time. It must be surgically implanted, but cardio-pulmonary bypass is often avoided.ConclusionTemporary support with Levitronix VAD may allow successfulrecovery of cardiac function or provide bridge-to-transplant in asignificant number of patients.
Temporary epicardial biventricular pacing: a strategy to improvehaemodynamic performance and post-operative outcomesD.E. Thomas,1 C. Tan,2 M. Gallagher1, P O’Callaghan1, and Z.R.Yousef,11 Department of Cardiology, University Hospital of Wales, UK2 Department of Anaesthetics, University Hospital of Wales, UKAs the spectrum of cardiac surgery shifts towards higher risk patientswith multiple co-morbidities, advanced age, complex coronary arterydisease and most significantly impaired left ventricular (LV) function,strategies aimed at improving LV function in the peri-operative periodare increasingly important.In the non-surgical setting, the technique of cardiac resynchronisationtherapy (CRT) delivered through transvenous biventricular (BiV)pacing has been shown to; improve acute LV haemodynamics, exertfavourable LV remodelling, enhance patient’s functional capacity andsignificantly extend longevity.There is little data however examining the role of BiV pacing in theperi-operative cardiac surgical setting. We present the results of a pilotstudy investigating the application of temporary epicardial BiV pacingin the immediate post-operative period.MethodsOver 4 months, 6 patients (83% male) undergoing CABG with severeLV systolic dysfunction (ejection fraction <35%) received temporaryepicardial CRT in addition to routine post-operative care. Mean age:71±7yrs, mean EuroScore: 8.6.Standard temporary epicardial pacing wires were attached to the rightatrium (RA), right ventricle (RV) and the postero-lateral surface of theLV. After chest closure, wires were connected to a typical externalpacing box as follows: RA to RA port, RV and LV leads to RV portthereby enabling external pacing in various configurations: RV only(standard practice), LV only, or simultaneous RV and LV pacing (BiVpacing mode). Atrio-ventricular (AV) sequential pacing wasmaintained throughout (AV delay 110-150ms) in patients with sinusrhythm.On transfer to the intensive care unit, haemodynamics were recorded(pulmonary artery catheter) on fixed concentrations of inotropes at 4different pacing modes: a) intrinsic (no epicardial pacing), b) RV, c)LV, and d) BiV. Where a paced mode yielded the best haemodynamicprofile, patients were paced at this configuration (lower pacing rate setat 10beats/minute above intrinsic rate) for as long as required.Thereafter, epicardial leads were extracted in normal fashion.Results RV LV BiV IntrinsicCO (l/min) 5.3±1.29 5.62±1.10 5.78±1.06 5.64±1.34CI (l/min/m2) 2.54±0.49 2.69±0.35 2.77±0.38 2.71±0.50PAWP(mmHg) 16.16±6.2 16.16±6.2 16.5±6.1 16.0±6.6SVR (ds/cm5) 1000±344 971±277 885±257 893±209DiscussionTemporary epicardial BiV pacing appears to produce superiorhaemodynamics when compared to standard RV pacing, causing asignificant increase in CI (p<0.05). Our findings warrant furtherinvestigation in the form of a randomised trial examining the role oftemporary epicardial cardiac resynchronisation therapy on outcomesin the peri-operative setting.AcknowledgementsDepartments of Cardiothoracic Surgery and Intensive Care, UHW
A survey of anaesthetic cover of UK cardiac intensive care unitsJ. Butcher, R.A. Kumar and J.A. DunneDepartment of Anaesthetics, University Hospital of Wales, Cardiff,UKIt has been suggested that cardiothoracic anaesthetists should act asintensivists and lead the care of post operative patients in the CardiacIntensive Care Units (CICU). This survey was designed to look atthe cover provided by consultant cardiac anaesthetists in the UKCICUs.MethodsCardiothoracic anaesthetists in all UK cardiac centres were contactedvia e-mail and telephone. Specialist, “stand alone” centres wereexcluded. Our survey included questions on numbers of cases peryear, presence of a dedicated CICU, numbers of consultantanaesthetists, proportion of full time cardiac anaesthetic consultants,number of weekly consultant sessions, patterns of consultant cover,patterns of dedicated junior cover and whether multi-organ failure wasmanaged on the CICU.ResultsWe obtained data from 34 centres. The response rate was 100%. Allbut 2 had a dedicated CICU and managed multi-organ failure. Table 1shows the average work load and consultant numbersTable 1 Case-load and consultant cover pattern of CICUscases/year consultants/centre weekly Weekly CICUaverage average (range) consultant consultant(range) ICU cover sessions (%) average (range)981 8.7(6-18) 8.5 (0-12) 15 (44)(500-1600)Dedicated junior doctor cover for CICUs was variable with 12 (35%)of the units having both anaesthetic and surgical cover during the dayand 16 (47%) units having both at night.DiscussionOur survey has demonstrated considerable variation in levels andpatterns of staffing of cardiac CICUs across the UK. There is evidencethat providing dedicated intensivist cover and weekly workingpatterns reduce mortality and lengths of stay amongst the general ICUpatient population. There is as yet no evidence that this applies tothe cardiac ICU. However it seems logical that consistency andcontinuity of care are of paramount importance, with the consultantcardiac anaesthetist playing a key role in a multi-disciplinary approachto patient care.References1. Weiss SJ. Pro: Cardiothoracic anesthesiologists should runpostcardiac surgical intensive care units. J Cardiothorac Vasc Anesth2004; 18: 521-4.2. Pronovost PJ, Angus DC, Dorman T et al. Physician staffingpattern and clinical outcomes in critically ill patients: a systematicreview. JAMA 2002; 288: 2151-62.
Is HbA1c a Useful Predictor of Outcome After CardiacSurgery?M.I. Garcia-Vega1, N Jones1, M. Taylor3, M. Curtis3, A. Smith2,D. Farrar21 Clinical Fellow, 2 Consultant in Anaesthesia and Cardiac ICU3 Cardiothoracic Audit Nurse. Dept of Anaesthesia and ICU,Heart Hospital / UCH Foundation Trust, UKStudies have found elevated HbA1C to be a predictor of pooroutcome after cardiac surgery (1). Heart Hospital pre-assessmentclinic aims to carry out pre-operative HbA1c on diabetic patients.We audited this practice to assess if this was being carried out andwhether the result impacted cardiac surgical outcome in terms oflength of stay and mortality in our practice.MethodsUsing the cardiac surgery database, we retrospectively reviewed allconsecutive diabetic patients that underwent cardiac surgery in a twoyear period from April 2005. We established whether they underwenta pre-operative HbA1c and recorded the result if available. Resultswere grouped into good control (7 or less) and poor control (over 7).Length of ITU and hospital stay and mortality were also recorded asoutcome markers.Results442 records were examined of which only 150 (34%) had an HbA1cresult. No difference was observed in median ITU or hospital lengthof stay although mortality appeared to be higher in the poorlycontrolled diabetic group.DiscussionAs with previous studies, diabetic control seems related to mortalitybut not length of stay. Studies are needed to establish whetherimprovement in diabetic control can impact outcome.Reference1 HbA1c predicts length of stay in patients admitted for coronary artery bypass surgery. Medhi M et al. Heart Disease. 3(2):77-9, 2001 Mar-Apr
Setting up outreach in the cardiothoracic intensive care unit(CITU)B. Oughton and J.DunneCardiothoracic Intensive Care Unit, University Hospital of Wales,Cardiff, UKThe Department of Health published a document advocating a newapproach to care for the critically ill patients, based on clinical need asopposed to location1. The Department of Health’s vision to tackle thisissue was to establish an outreach service. Although all of theliterature is primarily related to general intensive care units we feelthat such a service offered to post-operative cardiac patients would beof benefit to our unit. An outreach service would facilitate promptdischarge of patients from our unit and also prevent unnecessaryreadmissions.MethodAll our patients were reviewed prior to discharge from CITU by aConsultant Anaesthetist and if necessary, were identified for theoutreach service. Criteria for selection included a prolonged stay onthe CITU, post heamofiltration, renal impairment, raisedinflammatory markers, tracheotomy patients and those with aneurological deficit. The Consultant referred any patient to theoutreach service if he/she felt they would benefit from a follow-upreview. These patients were followed up the next day by the CITUConsultant Anaesthetist and a senior staff nurse at the end of themorning round. The patients were reviewed at least once a day untilthe Consultant discharged the patient from the outreach service. Thereview was documented in the medical notes and the need for anyfurther intervention was passed on to the nursing and medical teamson the ward. Further advice and support were offered to the ward staffas necessary.Results Outreach activities 120 Jan07-Jun07 Jul06- DEC 06 100 80 60 Numbers 40 20 0 Referred to outreach Admitted to CICU Admitted to CICU without outreachFigure 1 Outreach referralFor the six months of 2007, 101 patients were referred to the outreachservice as compared to 111 for the same duration in 2006(Fig1).Mainreasons for follow-up were renal impairment and raised inflammatorymarkers.11 out of 21 patients(52%) readmitted to CITU were referredto outreach in 2007 as compared to 6 out of 16 (38%) in 2006. Patientreadmitted with out outreach were mainly for surgical interventionslike sternal rewiring.DiscussionOverall we believe the outreach service has been beneficial,particularly for facilitating the discharge from CITU and avoiding
unnecessary readmissions. Patients stated that they were reassured bythe continuing review by the CITU team of their progress .The wardstaff reported that they found the outreach service was very supportivein the further care of the patients.References1. Department of Health Comprehensive Critical Care. A review ofadult critical care services 2000 London.
Training in Transoesophageal Echocardiography for Higher andAdvanced Trainees in Cardiac AnaesthesiaM.H. Lane1, L.H. Hepburn1, S.I. Jaggar1, and S. Price2Department of Anaesthesia1, Royal Brompton Hospital, UKDepartment of Intensive Care2, Royal Brompton Hospital, UKIn the United Kingdom (UK) ~ 10% of all echocardiogramsperformed are transoesophageal (TOE), of which 90% are completedby cardiac anaesthetists . In North America, training in cardiacanaesthesia includes TOE. In the UK, training and accreditation inTOE is overseen by the British Society of Echocardiography, andpublished recommendations for trainees in cardiac anaesthesia includethe development of skills in TOE . The aim of this audit was toassess current TOE training provision and organisation for cardiacanaesthesia trainees in the UK.MethodA postal survey of the 43 cardiothoracic surgical centres in the UKwas performed . Questions aimed to determine the number of casesper centre, case mix and TOE use, and details of the organisation ofTOE training programmes.ResultsThe response rate was 62%. The average annual caseload per centrewas 834 (range 80 – 1800).Table 1 Case mix and frequency of TOE use <20% cases 20-80% cases >80% cases CABG 62% 24% 14% High risk CABG 10% 52% 38% CABG & valve 5% 10% 85% Valve 5% 0% 95% ACHD 10% 0% 85%There was no access to any TOE training in 14% of centres, and adedicated in-house training programme in only 43% of centres. Thesein-house training programmes all included hands-on experience with atrainer. The primary trainers were anaesthetists in all centres. Onecentre also had a cardiologist as a primary trainer. More formaltraining included; didactic lectures (44%), study reporting (56%) andlogbook (67%). Training was delivered in 22% by anaesthetists withonly basic experience (no formal TOE qualifications). Training by anadvanced TOE practitioner was available in only 44% of trainingprogrammes.DiscussionA formal qualification in TOE is now expected of new consultantcardiac anaesthetists in the UK. Ad hoc exposure to TOE is thereforeno longer adequate for training in cardiac anaesthesia. Our surveydemonstrates that formal exposure to TOE training is not universallyavailable to cardiac anaesthetic trainees. Further, where provided it isseldom by advanced practitioners and at times, by anaesthetists withno formal TOE qualifications. Thus, the current provision andorganisation of TOE training does not meet the requirements statedfor training in cardiac anaesthesia . This has implications for thefuture organisation of TOE training for cardiac anaesthetists in theUK.References1 Transoesophageal echocardiography in the operating room. J. D. Kneeshaw. British Journal of Anaesthesia. 97(1):77-84 (2006).2 The Royal College of Anaesthetists. The CCT in Anaesthesia IV: Competency based Higher and Advanced levels (ST years 5, 6 & 7) Training and assessment. January 2007.
Echocardiography for Diagnosis of Cardiac TamponadeFollowing Repair of Traumatic Diaphragmatic HerniaDr H. Velásquez 1, Dr L. Pardeshi 1, Dr S. Ahmed 1, Mr B. Nyawo 2Mr S. Barnard 21 Department of Cardiothoracic Anaesthesia, Freeman Hospital,Newcastle upon Tyne, UK2 Department of Cardiothoracic Surgery, Freeman Hospital,Newcastle upon Tyne, UKWe report a case of cardiac tamponade twenty four hours followingrepair of a traumatic diaphragmatic hernia.A previously healthy 41 year old male presented to hospital with aneight week history of shortness of breath particularly early in themorning and late at night. He also reported occasional retrosternalpain which resolved spontaneously. He alleged assault two yearsearlier. A chest x-ray showed an opacification at the left lung base. ACT-scan confirmed a diagnosis of a diaphragmatic rupture.The patient underwent elective repair of the hernia via a leftposterolateral thoracotomy. Colon and omentum were found in thechest, occupying about a third of the hemithorax. There was also adefect approximately 7 centimetres in the posterior part of thediaphragm. A Marlex® patch was used to cover the diaphragmaticdefect once the hernia was reduced. Overnight the patient becameoliguric and progressively acidotic, unresponsive to initial fluid andinotropic therapy. He developed abdominal distension and elevatedCVP. A presumptive diagnosis of abdominal compartment syndromewas made. Intrabdominal pressure measured via bladder was raised to23 mmHg. Abdominal CT was reported as normal, apart from a smallpericardial effusion. His condition deteriorated with respiratorydistress requiring intubation and ventilation. A transthoracicechocardiogram was performed to rule out other possible explanationfor his haemodynamic changes. The echocardiogram demonstrated asignificant pericardial effusion with evidence of tamponade. Thepatient was taken to theatre for emergency laparotomy. As the MAPremained low intra-operatively, a pericardial window was created.Drainage of the pericardial space revealed 300ml of blood. The patientimmediately improved with rising MAP and falling CVP. The patientsubsequently made an unremarkable recovery.DiscussionEchocardiography has shown to be a useful tool in assessing cardiacoutput right heart pressures and LV filling pressures (1). When used inthis case it also allowed us to confirm the presence of a pericardialeffusion, which initially was thought not to be compromising thepatient. However, the lack of a marked improvement inhaemodynamics after the laparotomy and the significant increase inMAP and decrease in CVP after draining the pericardial effusion ledus to believe that the pericardial effusion was the main factor in thepatient instability.The aetiology of a pericardial effusion post-diaphragmatic herniarepair still remains unclear as no obvious cause was found.We believe that echocardiogram should be used as an early tool in theclarification of the possible cause of haemodynamic instability afterrepair of traumatic diaphragmatic hernia. It can also provide accurateinformation regarding cardiac filling status and cardiac function,which would be otherwise difficult to assess in the presence ofincreased intrabdominal pressures. In the case of left diaphragmatichernia, echocardiography can give vital information regarding thepresence and significance of a pericardial effusion post-repair.References1. Oh J. Echocardiography as a Noninvasive Swan-Ganz Catheter.Circulation 2005; 111: 3192-3194.
2. Hunter J, Damani Z. Intra-abdominal hypertension and theabdominal compartment syndrome. Anaesthesia 2004; 59: 899-907.3. Bailey J, Shapiro M. Abdominal compartment syndrome. Crit Care2000; 4: 23–29.
Intraoperative use of transoesophageal echocardiography inroutine mitral valve replacement – justified standard?P.Olszowka2, A. Azzu2, S. Karthikeyan11. Department of Cardio-Thoracic Anaesthesia, University Hospital of Wales, UK2. Department of Cardio-Thoracic Surgery, University Hospital of Wales, UKThe role of intraoperative transoesophageal echocardiography (TOE)in valve replacement surgery is still not well established. The aim ofpresenting this case was to justify a standard use of TOE in routinevalve replacement surgery.The patient admitted for elective mitral valve replacement withcoronary artery bypass grafting underwent surgery in our centre. Shewas known to have moderate aortic stenosis. Intraoperativeassessment with TOE confirmed moderate aortic stenosis withrestricted movement of non coronary cusp due to calcifications. Themitral valve was replaced with a mechanical valve St Jude, aorticvalve was decalcified and single vein graft to RCA was anastomosed.Before coming off bypass TOE revealed for a short time one stuckleaflet of the prosthetic valve (fig 1). However, later both leaflets weremoving easily. The patient was weaned easily from cardiopulmonarybypass without inotropic support. Postoperative TOE in theaterrevealed both leaflets were mobile with an extra echo shadow abovevalve in left atrium (fig.1). Re-exploration confirmed presence ofresidual tissue across the valve.Figure 1. Stuck leaflet of St Jude valve in mitral position (a). Extraecho shadow above the valve(b).a bCONCLUSIONS: The intraoperative use of TOE plays an importantdiagnostic and therapeutic role in valve replacement surgery andshould be widely implemented.
How common is heparin resistance in cardiac surgery?M.S.R.R. Ganugapenta and A. KleinDepartment of Anaesthesia,Papworth Hospital, UKHeparin Resistance (HR) is a well-known finding in patientsundergoing surgery with cardiopulmonary bypass (CPB). Theincidence is variable, as the definition is variable, and there aredifferences in local guidelines and equipment used to measureactivated clotting time (ACT). Timely recognition of HR andappropriate management is essential; failure to recognize it can lead toserious complications ranging from subclinical disturbances in thecoagulation cascade to severe coagulopathy or even catastrophicintraoperative coagulation of the cardiopulmonary bypass circuit .Risk factors identified in the literature include age ≥ 65 years,previous exposure to intravenous or subcutaneous heparin and aplatelet count ≥ 300 × 109/L .MethodsA retrospective analysis was done over a three month period in asingle centre. We defined HR as an ACT below 400 after the bolusdose of heparin (300iu/Kg), needing further supplementation beforeinstitution of CPB.ResultsThe incidence of heparin resistance was 8.1% (40/494). All patientswere managed with further doses of heparin except for one who alsoreceived fresh frozen plasma. 72% (29 of 40) of patients were aged 65or more, 20% (8 of 40) had received preoperative heparin, 37.5% (15of 40) had platelet count ≥ 300 x109/L and 5% (2 of 40) had all 3 riskfactors. The mean duration of CPB was 93.6 min.Table 1 Dose of heparin administered Mean SDHeparin bolus dose (iu) 22,000 4000Supplemental heparin if required (iu) 14000 8000Number of supplemental boluses 2 2DiscussionHR is common, but management is usually straightforward ,with extraheparin being sufficient to elevate ACT to safe levels. Howeverheparin supplementation delays institution of CPB while ACT is re-measured. These results indicate that the initial dose of heparin mayneed to be increased in our patient population, but overdosage is notwithout complications. Excessive administration of heparin may beassociated with re-heparinisation some time after reversal withprotamine, leading to increased post-operative bleeding. Othermethods of HR management include administration of fresh frozenplasma, antithrombin III concentrate or direct thrombin inhibitors.References1 Staples MH, Dunton RF, Karlson KJ, Leonardi HK, Berger RLHeparin resistance after preoperative heparin therapy or intraaorticballon pumping. Ann Thorac Surg 1994; 57: 1211-16.2 Ranucci M, Isgro G, Cazzaniga A, Soro G, Menicanti L, Frigiola A.Predictors for heparin resistance in patients undergoing coronaryartery bypass grafting. Perfusion 1999; 14: 347-42.
Are the transfusion benefits of minimal extracorporeal circulation(MECC) for CABG sustained in ITUK Fehrmann, M H Spivey, P M Robbins, C T Lloyd and M J BennettSouth West Cardiothoracic Centre (SWCC), Plymouth, UKMECC is a new approach to Cardio-Pulmonary Bypass (CPB).Features include: Minimal priming volume (≤ 800 ml), no venousreservoir, centrifugal pump, no cardiotomy suction reservoir,increased blood:cardioplegia ratio and a covalent heparin coating.There is no blood-air interface and reduced foreign-body contact.These features permit a reduced heparin dose. Potential benefitsinclude less systemic inflammation and haemostatic activation, lesscoagulopathy and improved end-organ function.Several trials have shown significant reductions in perioperativetransfusion requirement (U/patient) - MECC (0.46 ± 0.88), CPB (0.87± 1.62), or OPCAB surgery (0.94 ± 1.96)1, markedly lesshaemodilution and perioperative blood loss (222 ± 101 ml MECC v349 ± 206 ml CPB)2 and a reduction in blood transfusionintraoperative(8.6% v 31%) and during recovery (39% v 79%) 3.MethodsIntraoperative data was collected (one surgeon) and compared withprevious controls (blood bank database – any surgeon) for primaryCABG using CPB. We considered transfusions in the first 48 hoursfrom start of surgery. The aim was to see if the anticipated favourablehaematological profile of MECC was maintained in the CICU.Results36 cases were analysed, including one redo CABG and one Jehovah’sWitness. Mean Euroscore was 2.9. Average number of grafts: 2.85 (±0.6), average age 68.3 (± 8.7) yrs. Mean prime volume was 390 (±161) ml. Mean volume added was 64 (± 101) ml with a meancardioplegia volume of 105 (± 31) ml. The mean cell salvage volumereturned was 231 (± 195) ml.One patient reached the transfusion trigger (Hb < 7g/dl)intraoperatively. The mean fall in Hb was -16.3% ± 8.9 ( pre-bypassHb to first Hb in CICU). Historical controls: -30% ± 5.8. Mean firstHb on CICU was 10.6 (± 1.7) g/dl.Two patients (5.8%) returned to theatre for bleeding. After 48 hours12/36 (33.3%) patients had received ≥1 units PRBC, 4/36 (11.1%)received FFP and 5/36 (13.9%) received ≥1 ATD of platelets. Theserates of transfusion were not different to the rates in the control group.DiscussionRequirement for product transfusion is multifactorial. Intraoperativereductions due to MECC may reflect less haemodilution, an improvedcoagulation profile, and less vasodilatation conserving central bloodvolume. However during recovery some of these factors lose theirinfluence.This small review does not demonstrate a sustained improvement intransfusion requirement. However, compared with other reports3 thetotal number of transfusions was markedly less. Randomised trials arenecessary to determine the postoperative factors that seem to reversethe beneficial characteristics of MECC.References1. Gerritsen WB et al. Transfusion Medicine 2006; 16: 329-334.2. Bical OM et al. European Journal of Cardiothoracic Surgery 2006; 29: 6993. Liebold A et al. Journal of Thoracic Cardiovascular Surgery 2006; 131: 26