Methylene blue does not neutralize heparin after cardiopulmonary bypass.
OBJECTIVE
It was hypothesized that methylene blue could neutralize heparin in patients after cardiopulmonary bypass and become an alternative to protamine.


METHODS
This was a prospective unblinded study with patients serving as their own controls. SETTING PARTICIPANTS: A single, large university hospital. This study was conducted in patients scheduled for elective aortocoronary bypass grafting.


METHODS
When heparin was to be neutralized, patients received methylene blue, 2 to 12 mg/kg, diluted in 50 mL and infused over 20 minutes. If a clot was not observed or the activated coagulation time (ACT) remained elevated, protamine, 250 mg, was administered and the ACT was repeated.


RESULTS
No patient demonstrated clot after methylene blue infusion. ACT did not return to preheparin values in any patient. All patients required protamine to establish hemostasis. Protamine restored the ACT to preheparin values in every patient. The one patient who received 12 mg/kg experienced severe pulmonary hypertension.


CONCLUSIONS
Methylene blue does not neutralize heparin after cardiopulmonary bypass.
Metz
S
S
Department of Anesthesiology, Hahnemann University, Philadelphia, PA 19102, USA.
Horrow
J C
JC
Goel
I P
IP
Kuretu
M L
ML
Bellwoar
C
C
D000925:Anticoagulants / Q000494:pharmacology*; D002315:Cardiopulmonary Bypass; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D008751:Methylene Blue / Q000494:pharmacology*; D011446:Prospective Studies; D011479:Protamines / Q000494:pharmacology
D000925:Anticoagulants; D011479:Protamines; D006493:Heparin; D008751:Methylene Blue