Abdominal Surgery Rotation

Blood transfusion does not simply involve the anesthesiologist hanging pRBCs once 1000 ml of blood are in the suction container! Correct pre-operative anemia Minimize intra-operative blood loss Optimize blood replacement Though these things don’t seem to be within our control we can at least go into surgery armed with some data…

Difficult for anesthesiologist to have a role since we often see patients the day before surgery Can consider: IV iron or erythropoetin Will increase hemoglobin by 1-2 g/dL but requires 2 weeks for maximal effect

Things we can do: Maintenance of normothermia Controlled hypotension Meaning a MAP that is SAFE for the patient, not necessarily what the surgeon wants! Consider use of regional anesthesia for pain control and BP effects Cell salvage and re-transfusion Usually a decision made by surgeon

And now for some data…

838 ICU patients randomized to: Restrictive transfusion- pRBCs for Hgb < 7, goal 7-9 Liberal transfusion- pRBCs for Hgb <10, goal Overall 30-day mortality was similar but… If APACHE II score was <20 (less sick pts, see next slide) Mortality was 8.7% (restrictive) vs. 16.1% (liberal) If age was <55 years Mortality was 5.7% (restrictive) vs. 13.0% (liberal) If patient had acute MI or unstable angina Mortality was similar in both groups Hebert et al. NEJM, 1999.

Rectal temperature HR RR MAP Aa gradient or PaO2 pH Na K Cr Hct WBC Glasgow coma scale Age Chronic disease Higher number is worse Correlations have been made between APACHE II score and morbidity/mortality Score based on 14 parameters scored 0-4 points each:

Meta-analysis of 45 cohort studies including 272,596 patients Outcomes included mortality, multi-organ dysfunction syndrome (MODS), acute respiratory distress syndrome (ARS) & infections In 42 studies the risk of transfusions outweighed the benefit (higher mortality & morbidity- MODS, ARDS, infections) In 2 studies the risk was neutral (benefit = risk) In 1 study the benefit outweighed the risk But…the only adequately powered, randomized trial on transfusion requirements is TRICC! Marik & Corwin. CCM, 2008.

But this is all in the ICU… What about in the OR?

Does preoperative anemia in patients having major non-cardiac surgery alter morbidity and mortality? Retrospective analysis of 227,425 patients undergoing major surgery

After controlling for other risk factors (Age, DMII, cardiac dx, COPD, CRI, cancer) Post-op mortality at 30 days was higher in those with pre-operative Hct < 36 for females or <39 for males with an odds ratio of 1.42 (confidence interval ) This means anemia increased mortality 1.42 fold! Post-op morbidity at 30 days was higher in those with pre-operative anemia with odds ratio 1.35 (confidence interval ) This means anemia increased complications 1.35 fold!

Analysis also showed increased mortality WITH blood transfusion! Authors conclude that pre-operative anemia should be treated with iron supplementation or erythropoeitin administration (if time allows) NOT transfusion!

Does intraoperative transfusion of 1-2 units of pRBCs in patient with Hct < 30 affect morbidity and mortality? **This study group is VERY relevant to our practice- think of how often you transfuse “just” one or two units intraoperatively!** Retrospective analysis of 10,100 patient undergoing general, vascular or orthopedic surgery with preoperative hct < 30 Anesthesiology

Hct prior to transfusion not reported Authors conclude that intraoperative transfusion leads to higher morbidity and mortality but it could be EITHER the transfusion or the increased surgical bleeding/complications that are the direct CAUSE! Remember: correlation  causation

Surgeons HATE to look up and see red (ie. blood hanging) without it being discussed with them If you feel that a transfusion is indicated, discuss it with the surgery team FIRST!

Single donor, volume ml Hct ~70% 1 unit increases Hgb ~1g/dl Theoretically not compatible with LR because it may chelate calcium and clot Stored in: Citrate- anticoagulant binds Ca Phosphate- buffer Dextrose- energy source Adenosine- precursor for ATP synthesis

Contains coagulation factors Use ABO-compatible Stored frozen, use within 24 hrs of thawing 1 unit increases clotting factors 2-3% Can be used to treat heparin resistance (antithrombin III deficiency) in patients requiring heparinization Most often seen with patients going on bypass

Stored at room temperature for <5 days “6-pack” used to refer to pooling of platelets from 6 donors which is rarely done anymore These days when you ask for a “6-pack” you get an apheresis unit which has platelets from a single donor (volume ml) and will increase plt count ~ 50,000

Fraction of plasma that precipitates when FFP is thawed Contains factors VIII, XIII, fibrinogen, fibronectin 1 unit contains 5 x more fibrinogen than 1 unit of FFP Usually used to replace fibrinogen <100 mg/dl with microvascular bleeding or in patients with vWF disease

1. The most common cause of mortality associated with blood transfusion is: A. ABO hemolytic transfusion reaction B. Non-ABO hemolytic transfusion reaction C. Microbial infection D. Transfusion associated circulatory overload (TACO) E. Transfusion associated acute lung injury (TRALI)

E. TRALI is the most common cause of mortality associated with transfusions (51%), followed by non- ABO hemolytic transfusion reaction (20%), microbial infections (12%), ABO hemolytic transfusion reaction (7%), TACO (7%) and other (2%).

2. Which of the following is MOST likely to be a manifestation of citrate toxicity? A. Hypotension B. Short QT interval on ECG C. Peaked T waves on ECG D. Wide pulse pressure

A. Hypotension. Citrate is used as an anticoagulant in banked blood and chelates ionized calcium. It can have the same effect on iCa in the body. The manifestations of citrate intoxication are the same as those observed with hypocalcemia: Prolonged QT, flattened T waves Decreased contractility with hypotension Narrowed pulse pressure Increased LVEDP, increased CVP Normally citrate is metabolized by the liver. Can become elevated in massive transfusion, liver failure, hypothermia. More common with FFP administration Treat with IV calcium

Glance LG et al. Association between Intraoperative Blood Transfusion and Mortality and Morbidity in Patients Undergoing Noncardiac Surgery. Anesthesiology. 2011; 114(2): Hebert PC et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. NEJM. 1999; 340 (6): Marik PE & Corwin H. Efficacy of red blood cell transfusion in the critically ill: A systematic review of the literature. CCM. 2008; 36(9): Musallam KM et al. Preoperative anaemia and postoperative outcomes in non-cardiac surgery: a retrospective cohort study. Lancet. 2011; 378: 1396–407. Spahn DR et al. Patient blood management. Anesthesiology. 2008; 109: