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Influence of Cardiopulmonary Bypass on Nitroglycerin Clearance
Author(s) -
Dasta Joseph F.,
Weber Robert J.,
Wu Lei Shu,
Sokoloski Theodore D.,
Kakos Gerard S.,
Smith Douglas F.,
Howie Michael B.
Publication year - 1986
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1986.tb02928.x
Subject(s) - cardiopulmonary bypass , medicine , anesthesia , coronary artery bypass surgery , vein , artery , venous blood , cardiac surgery , radial artery , cardiology
The effect of cardiopulmonary bypass on the clearance of nitroglycerin (NTG) was studied in seven patients scheduled for coronary artery bypass graft surgery. Intravenous NTG was administered through nonadsorbing tubing at a starting dosage of 5–10 μg/min and was adjusted as needed. Blood samples were obtained from the radial artery and antecubital vein before bypass and from the arterial outlet of the oxygenator during bypass at least 30 minutes apart during a constant dosage or at least 30 minutes after a dosage change. Serum concentrations were analyzed for NTG by gas chromatography. Venous NTG concentrations were always lower than concurrent arterial concentrations, with an average arteriovenous extraction of 67.2%. Serum concentrations of NTG were generally within the range associated with a therapeutic response in congestive heart failure patients. Consistent with other reports, NTG concentrations varied widely among patients and considerable intrasubject fluctuations in drug concentrations were seen. The mean ± SD apparent clearance of NTG before bypass of 0.044 ± 0.02 L/kg/min increased 20% to 0.052 ± 0.02 L/kg/min during bypass ( P = .05). These results suggest that cardiopulmonary bypass increases the clearance of NTG; however, the magnitude appears to be small and only partially explains the reported increased dosage needed during cardiopulmonary bypass .