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

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.