Abdominal Surgery Rotation - PowerPoint Presentation

Slide1

Abdominal Surgery Rotation

Evidence-Based

Blood TransfusionSlide2

Blood transfusion does not simply involve the anesthesiologist hanging pRBCs

once 1000 ml of blood are in the suction container!Correct pre-operative anemiaMinimize 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…

Patient blood managementSlide3

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

1. Correct pre-operative anemiaSlide4

Things we can do:Maintenance of

normothermiaControlled 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-transfusionUsually a decision made by surgeon

2. Minimize intra-operative blood lossSlide5

3. Optimize blood replacement

And now for some data…Slide6

838 ICU patients randomized to:

Restrictive transfusion- pRBCs for Hgb < 7, goal 7-9

Liberal transfusion-

pRBCs for Hgb <10, goal 10-12

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

The trial that started it all: TRICC

Transfusion Requirements In Critical Care

Hebert et al. NEJM, 1999.Slide7

Rectal temperatureHR

RRMAPAa gradient or PaO2

pH

NaK

Cr

Hct

WBC

Glasgow coma scale

Age

Chronic disease

APACHE II:

Acute Physiologic and Chronic

Health Evaluation scoring system Higher number is worseCorrelations have been made between APACHE II score and morbidity/mortality

Score based on 14 parameters scored 0-4 points each:Slide8

Meta-analysis of 45 cohort studies including 272,596 patientsOutcomes 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 riskBut…the only adequately powered, randomized trial on transfusion requirements is TRICC!

And then the meta-analysis…

Marik

& Corwin. CCM, 2008.Slide9

But this is all in the ICU…

What about in the OR? Slide10

Does preoperative anemia in patients having major non-cardiac surgery alter morbidity and mortality?

Retrospective analysis of 227,425 patients undergoing major surgerySlide11

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 1.31-1.54)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 1.3-1.4)

This means anemia increased complications 1.35 fold!Slide12

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!

BUT…Slide13

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. 2011.Slide14

Transfusion of 1-2 units intraoperatively increased mortality and morbidity at 30 daysSlide15

Hct prior to transfusion not reportedAuthors 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

But…Slide16

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!

On the practical side…Slide17

Single donor, volume 250-300 mlHct ~70%

1 unit increases Hgb ~1g/dlTheoretically not compatible with LR because it may

chelate

calcium and clotStored in:Citrate- anticoagulant binds CaPhosphate- buffer

Dextrose- energy source

Adenosine- precursor for ATP synthesis

The Basics:

pRBCsSlide18

Contains coagulation factorsUse ABO-compatibleStored 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

heparinizationMost often seen with patients going on bypass

The basics: FFPSlide19

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 200-400ml) and will increase

plt

count ~ 50,000The Basics: PlateletsSlide20

Fraction of plasma that precipitates when FFP is thawedContains factors VIII, XIII, fibrinogen, fibronectin

1 unit contains 5 x more fibrinogen than 1 unit of FFPUsually used to replace fibrinogen <100 mg/dl with

microvascular

bleeding or in patients with vWF disease

The Basics: CryoprecipitateSlide21

The most common cause of mortality associated with blood transfusion is:

ABO hemolytic transfusion reactionNon-ABO hemolytic transfusion reaction

Microbial infection

Transfusion associated circulatory overload (TACO)

Transfusion associated acute lung injury (TRALI)

Board Review questionsSlide22

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%).

AnswerSlide23

Which of the following is MOST likely to be a manifestation of citrate toxicity?

HypotensionShort QT interval on ECG

Peaked T waves on ECG

Wide pulse pressure

Board Review questionsSlide24

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 wavesDecreased 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

AnswerSlide25

Glance LG et al. Association between Intraoperative

Blood Transfusion and Mortality and Morbidity in Patients UndergoingNoncardiac Surgery. Anesthesiology. 2011; 114(2): 283-292.Hebert PC et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. NEJM. 1999; 340 (6): 409-17.

Marik

PE & Corwin H. Efficacy of red blood cell transfusion in the critically ill: A systematic review of the literature. CCM. 2008; 36(9):2667-2674.

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: 951-3.

References