Presentation on theme: "Transfusion Thresholds in the Elderly Surgical Patient"— Presentation transcript:
1Transfusion Thresholds in the Elderly Surgical Patient Transfusion Medicine Journal ClubShuen Tan~ anesthesiologist, skeptic, and budding blood conservationist ~January 8, 2009
2The effects of liberal versus restrictive transfusion thresholds on ambulation after hip fracture surgeryFoss, NB, Kristensen MT, Jensen PS, Palm H, Krasheninnikoff M, Kehlet HTransfusion epub (accepted for publication August 25, 2008)
3The Issues Is age a disease? If so, what is old?How do surgical patients differ from medical patients?How does that affect decisions to transfuse?
4“There’s chronological age and there’s physiological age.” - Amit Chopra
5Physiologic effects of age Decrease in physiological reserve“This decline is evident by the third decade and is gradual and progressive, although the rate and extent of decline vary.”CardiovascularHypotensive response to HR, hypovolemia, or arrhythmia CO/HR response to stressHarrison’s 16th ed., pp , 2005
6Physiologic effects of age RespiratoryV/Q mismatch lung elasticity, chest wall compliance resting pO2MSK/NeuroOsteopeniaStiffer gait, body swayHarrison’s 16th ed., pp , 2005
7Transfusion thresholds TRICCSick but not bleedingNo difference in mortality with Hb vsSurgical patientsBleeding but not sickDilutional anemia / Fluid shiftsGuidelines vague, depending on clinical situationHebert et al., NEJM 1999; 340: 409Nuttall et al., Anesthesiology 2006; 105: 198
8MethodsProspective, single-centre (Denmark), randomized, double-blind studyHip fracture patientsFebruary 2004 to July 2006Inclusion criteria:Primary hip #, age >65, independent walking pre-fracture, community dwelling, intact cognition
9Exclusion criteriaMultiple #s, terminal condition, alcoholism, chronic transfusion, acute cardiac or severe medical condition, contraindication to neuraxial blockPost-op immobilization, transfer for medical complications, return to OR within 4 days
10MethodsPowered to show 25% reduction in CAS with =0.05 and power of 0.80Assumed 69% transfusion rate with liberal threshold120 patients, 60 in each armLiberal group transfused at Hb<10 g/dLRestrictive group transfused at Hb<8 g/dL
11Methods Standardized perioperative care Standardized fluid therapy by weightHb on admission, in PACU, and OD x 5Intraop PRN onlyAllocation revealed only if Hb<10, to attending physician only
12Outcomes Primary Secondary CAS analyzed per-protocol Length of stay, cardiac complications, infectious complications, 30-day mortalityMeasured by intention-to-treatAnemia score by PT
13The Cumulated Ambulation Score (CAS) Locally developed and validatedLength of stay, time to discharge, 30-day mortality, and major medical complications decreased with CAS >9Numerical representation of patient’s functional mobilityThree parameters assessed on 3-pt. scaleMax score = 6Cumulated over POD 1-3Predictive of postop rehabilitation outcomeFoss, Clin Rehabil 2006; 20:701.
14ResultsDemographicsMore patients with ASA 3 in restrictive group (p=0.02)More pins/screws in restrictive group (0.05)More SHS and IMHS in liberal group (0.02)Predictive of increased blood loss (?)IMHS and pins/screws are outliersDHS and arthroplasty similar for blood lossFoss and Kehlet, J Bone Joint Surg Br 2006; 88: 1053
15ResultsTransfusionMore patients exposed in liberal group (74% vs. 37%)More transfusions in liberal group (p<0.0001)
20Well-defined patient population Restrictive group “sicker” at baseline 1. Were there clearly defined groups of patients, similar in all important ways other than exposure to the treatment?Well-defined patient populationRestrictive group “sicker” at baselineLarger proportion of ASA 3 patientsSurgeries similar in intention-to-treat analysisMore SHS and IMHS in liberal groupBlood loss similar
21“You’re forgetting the two most important determinants of intraoperative blood loss -- the surgeon and the anesthesiologist.”- Brian Muirhead
22Technically double-blind Clinical and subjective assessment of anemia 2. Was the assessment of outcomes either objective or blinded to exposure?Technically double-blindPatient and PT unaware of allocationClinical and subjective assessment of anemiaAttending physician aware of transfusion groupInteraction with PTLab reports on chart or computer?
23Primary outcome measured over 3 days 3. Was the follow-up of the study patients sufficiently long and complete?Primary outcome measured over 3 daysValidated to predict longer-term outcomeSecondary outcomes measured (presumably) over hospital stay30 days for mortalityFollow-up complete for all patients~10% of patients excluded from per-protocol analysis
244. Do the results fulfill some of the diagnostic tests for causation? Did the exposure preceed the outcome?Probably, but timing of transfusion not reportedIs there a dose-response gradient?Not reportedIs there any positive evidence from a dechallenge-rechallenge study?Is the association consistent from study to study?One previous study also showed no difference in ambulation with restrictive threshold60-day mortality in restrictive group: RR = 2.5Carson et al. Transfusion 1998; 38:522
25Does the association make biological sense? Plausible that increased Hb might lead to less fatigue, less CV complications, and less delirium, thus better ambulationHb values were similar throughout study despite different thresholdsAmbulation may be related more to multimodal rehab
27Multimodal Post-Fracture Rehab Dedicated hip fracture unitSurgery within 24 hoursEpidural at admission until 96 hours post-opSupplemental O2 while supinePerioperative LMWHEnforced perioperative nutrition and hydrationIntensive PT starting POD 0Foss et al. Clin Rehabil 2006; 20:701Foss and Kehlet. J Bone Joint Surg Br 2006; 88:1053
29What is the magnitude and precision of the association between the exposure and outcome? Primary outcome identical (CAS 9)Range similar between groupsHarm in restrictive group CV events: 10% vs. 2%, p=0.05 30-day mortality: RR = 2.1, p=0.02 Infectious complications: p = 0.19 Length of stay: p = 0.61
30Mortality 5 patients, all in restrictive group No pre-existing CV disease3 CV conditions1 sudden death, unexplained1 “general exhaustion”
321. Are our patients so different from those in the study that the results don’t apply? The uppermost echelon of hip fracture patientsDr. Shuen’s broken hipsNursing homeModerate dementiaWalkers and wheelchairsAnemic, cachectic, CV disease, anticoagulated, etc….500 patients screened for inclusion
34Benefits of avoiding transfusion 2. What is our patient’s risk of an adverse event, and potential benefit from the therapy?Average hip fracture patients at higher risk of CV complications than those in the studyRisk difficult to quantifyUnknown if raising transfusion threshold would mitigate riskBenefits of avoiding transfusionTRALI and TACO in susceptible populationCoagulopathyWound healing and infection?
353. What alternative treatments are available? Emergent surgery, limited time to optimize pre-op HbOther blood conservationEarly surgery, Cell-saver, anti-fibrinolytics, limited blood draws, nutritional supplementsAggressive multi-modal rehabIncreased monitoring and index of suspicion for CV events
36SummaryLiberalizing transfusion thresholds for elderly hip fracture patients does not improve post-op ambulationRestrictive thresholds may put patients at higher risk of CV morbidity/mortalityAny benefit associated with transfusion may be outweighed by the benefits of multimodal rehabilitation