Question 17.3

The following blood results are obtained in a patient post cardiac surgery.

a) What is the most likely cause of the abnormal coagulation profile ?

PT	13.9 seconds	10.5 to 13.5
INR	1.4	0.9 to 1.2
APTT	85 sec	24 to 39
ACT	240 seconds	<150 seconds

b) List 3 complications of the agent commonly used to correct the above coagulation abnormality.

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College Answer

Consistent with heparin

b) List 3 complications of the agent commonly used to correct the above coagulation abnormality.

Anaphylaxis Pulm HT Hypotension Bleeding Bradycardia

Discussion

The question "why does this post-bypass patient still have such a high ACT" is easily answered with "duh, heparin". However, the ACT could also be raised for a large number of reasons, and Practical-Haemostasis.com give a list of alternative possibilities, many of which could be relevant with this scenario.

Thrombocytopenia (the circuit ate my platelets)
Platelet antagonists
Factor deficiencies (the circuit ate my clotting factors)
Low fibrinogen, DIC etc
Hemodilution
Hypothermia (the patient returns from theatre with a core temperature of 33.0°C)
Lupus anticoagulant

Yes, perhaps too little protamine was given (the dose is usually 1mg per every 100 units of heparin).

However, protamine itself can have a potent anticoagulant effect in overdose.

Its other delightful side effects are discussed in (slightly) greater detail in the chapter on unfractionated heparin. briefly, they can be listed as follows:

Anaphylaxis
Urticaria
Bronchospasm
Pulmonary hypertension
Hypotension
Bradycardia
Decreased cardiac output
Paradoxical anticoagulation.

It also has antibacterial properties, mainly hitting the Gram-positives.

References

The PI for protamine sulfate is illuminating.

Ellison, Norig, Alan J. Ominsky, and Harry Wollman. "Is Protamine a Clinically Important Anticoagulant?." Anesthesiology 35.6 (1971): 621-629.

Holland, C. L., et al. "Adverse reactions to protamine sulfate following cardiac surgery." Clinical cardiology 7.3 (1984): 157-162.

Johansen, Charlotte, T. Gill, and Lone Gram. "Antibacterial effect of protamine assayed by impedimetry." Journal of applied bacteriology 78.3 (1995): 297-303.

Jastrzebski, J., M. K. Sykes, and D. G. Woods. "Cardiorespiratory effects of protamine after cardiopulmonary bypass in man." Thorax 29.5 (1974): 534-538.

Hobbhahn, J., et al. "[Complications caused by protamine. 1: Pharmacology and pathophysiology]." Der Anaesthesist 40.7 (1991): 365-374.

Fadali, Moneim A., et al. "Mechanism responsible for the cardiovascular depressant effect of protamine sulfate." Annals of surgery 180.2 (1974): 232.

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