1. ICU Management of the bleeding surgical patient
Cardiac
Aaron M Cheng

2. Post-operative bleeding
5-7% patients ml chest tube drainage/1st 24hrs post-op
5% require re-exploration for bleeding
Increased morbidity & mortality
Increased resource utilization

3. Patients known to be at increased risk for mediastinal bleeding
Patient variables
Preop Meds
Procedure variables
Older
Female/small BSA
Preop anemia
Adv cardiac disease
Comorbidities
Known coagulopathies
Hi dose ASA
Plavix/Prasugrel
LWMH ~18h
Fondaparinux ~ 48h
Warfarin
Emergency surgery after thrombolytic or IIb/IIIa inhibitors
Complex operations, esp. DHCA
Emergent/ Urgent operations
Re-operations
Use of bilateral mammary grafts

4. Adverse effects of re-exploration for bleeding
4.7 fold increase in mortality
Increased renal failure ± RRT (14% vs. 5.5%; 6.7% vs. 1.9%)
Prolonged Mechanical ventilation (42% vs. 12%)
Increased length of stay > 14d (26% vs. 12%)
Ann Thor Surg 2011; 91:

5. Return to the Operating Room After Cardiac Surgery Washington State

6. Medical Coagulopathy
Versus
Surgical Bleeding

7. Factors for increased bleeding unique to cardiac surgery
Dilutional coagulopathy
Hypothermia
Activation of coagulation, fibrinolytic, and inflammatory pathways

8. Surgery with cardiopulmonary bypass
Unique features
Blood is circulated for a prolonged period of time using plastic tubing
Massive anticoagulation by large bolus dosing
Divert blood away from surgical field (contrary to other surgeries) hemostasis (temporarily) is not essential for the surgical success

9. Elements of the CPB procedure
Priming fluid
Hypothermia
Oxygenator
Pumps
Reservoir
Cardiotomy
Cardioplegia
Anticoagulation

10. Dilutional coagulopathy: priming fluid
Typical adult circuits require liters of crystalloid or colloid
Prevents pumping air to patient; removes microparticulate of circuit
Significant hemodilution ~ 20-30%
CPB Hct =
Blood vol. X Pre-CPB Hct
Blood vol. + Prime vol.

11. Effect on platelets activation aggregation injury
Cardiopulmonary bypass: effects of contact with circuit tubing & oxygenator
Effect on platelets
activation
aggregation
injury

12. CPB
Thrombocytopenia
& Platelet dysfunction

14. Fibrinolysis

15. Fibrinolysis during cardiopulmonary bypass

16. Bleeding assessment in the ICU
Obtain immediate CXR as baseline—mediastinal & pleural spaces
Quantify bleeding amounts frequently—make sure tubes are patent
Optimize hemodynamics, temperature, acid-base status
Avoid Hypertension
Consider adding PEEP
Obtain coagulation studies—repeat after blood products administered
Repeat CXR if concerned about tamponade or undrained blood
Obtain ECHO if concerned about tamponade

17. General guidelines for re-exploration
> 400 mL/h for 1 hour (> 200 mL/m2)
> 300 mL/h for 2-3 hours ( > 150 ml/m2/h X 2-3h)
> 200 mL/h for 4 hours ( > 100 mL/m2/h X 4h)
Imminent cardiac tamponade better to avoid cardiac arrest & emergent ICU re-sternotomy

18. Laboratory Tests for severe post-op bleeding
Keep it simple Fewer tests means more rapid results
Is there enough to make a clot?
Platelets: number and function
Coagulation Factors: PT or PTT
Is the clot stable?
Fibrinolysis/DIC: Fibrinogen
Are there enough red cells?
Anemia: Serial HCT

19. The Emergency Hemostasis Panel: Does the patient need. . . .
Prothrombin Time/ INR/ aPTT
FFP? INR ≤ 1.5
Protamine? mg *
Platelet count
Platelets? Plt > 100
Fibrinogen
Cryoprecipitate? Fibrinogen ~ 200
Hematocrit
pRBCs? Hct ~ 30

20. Relationship of hematocrit & platelet function
Effect of 2-unit RBC apheresis or
plateletpheresis on bleeding time
Valeri et al. Transfusion 2001;41:

21. Other prohemostatic agents
Protamine
Desmopressin (DDAVP)
Antifibrinolytic agents: Lysine analogs
Prothrombin Complex Concentrates (PCC)
Recombinant Factor VIIA (rFVIIa)
Calcium

22. Protamine Reverses unfractionated heparin (does not reverse LMWH)
Can cause multiple adverse reactions (Anaphylaxis, acute pulmonary vasoconstriction, RV failure, hypotension)
Use small doses (5-15mg) for heparin rebound effects
Short ½ life of Protamine—virtually eliminated in 30min
Larger doses can elevate ACT and cause bleeding (Increase plt dysfunction, fibrinolysis, decrease clot strength)

23. Desmopressin (DDAVP) V2 analog of arginine vasopressin
Induces release of normal VWF & Factor VIII
Can be used post-operatively in patient’s with von Willebrand’s disease (quantitative defects)
May be useful in Uremia??
Dose 0.3 ug/kg IV over 20 min to avoid hypotension
Probably limited usefulness in patients with significant post-op bleeding & in patients already on vasopressin pressor therapy

24. Antifibrinolytics
Epsilon-Aminocaproic Acid (EACA) & Tranexamic acid—synthetic antifibrinolytics inhibits activation of plasminogen to plasmin
Demonstrated to reduce bleeding & transfusion requirement in cardiac surgery
TXA associated with increased convulsive seizures
Blocks GABA receptor in frontal cortex
AMICAR given intraoperatively at UWMC

25. Prothrombin Complex Concentrate
PCC (Mixture of Vit K dependent products)
3 factor (II, IX, X) or 4 factor (II, VII, IX, X)
Clotting factors 25 X higher than normal plasma
PCC vs. FFP (for reversal of coumadin anticoagulation)
Faster correction of INR
Less volume
Less risk of infections transmission/TRALI
Quicker to prepare—no cross matching required
Used in peri-op setting to reverse INR in patients with life-threatening intracerebral bleeding

26. NOVOSEVEN (rVIIa) rVIIa used off label for life-threatening hemorrhage
Binds to tissue factor at site of vascular injury to produce thrombin
In cardiac surgery (40-80 ug/kg):
Decreased reoperation for bleeding
Decreased blood product usage
Decreased chest tube drainage
Increase risk of arterial thromboembolic events
5.5% vs. 3.2% (placebo)
Coronary thromboembolic events (2.9% vs. 1.1%)
Subset at highest risk Age 65+ (9.0% vs. 3.8%)
NJEM 2010; 363(19):

27. COSTS BLOOD PRODUCT UWMC COST ($) pRBC 209.00 Platelets-apheresis
637.00
Platelets-pooled (5-unit pool)
707.00
FFP
72.00
Cryoprecipitate
328.00
Leukoreduction
41.00
Irradiation
11.00
Volume-reduction
59.00
Bebulin (3-factor PCC)
(2530 units)
NOVOSEVEN (rVIIa)
(4ml vial: 1mg/ml)