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Thiopentone levels during cardiopulmonary bypass
Author(s) -
MORGAN D. J.,
CRANKSHAW D. P.,
PRIDEAUX P. R.,
CHAN H. N. J.,
BOYD M. D.
Publication year - 1986
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.1986.tb12695.x
Subject(s) - cardiopulmonary bypass , medicine , bolus (digestion) , anesthesia , plasma concentration
Summary Plasma total and unbound concentrations of thiopentone were investigated during exponentially decreasing infusions in seven patients undergoing cardiopulmonary bypass. Total plasma thiopentone concentrations reached a plateau (10.2, SD 2.1 μg|ml) soon after the initial bolus dose and commencement of the infusion. Concentrations were maintained until the onset of cardiopulmonary bypass, whereupon total plasma thiopentone concentration fell abruptly to 50.0 (SD 5.8) percent of the prebypass level. The unbound fraction of thiopentone increased from 16.6 (SD 1.9) percent before bypass to a maximum to 29.3 (SD 5.6) percent during bypass (p < 0.01), decreased to 22.9 (SD 3.3) percent at the end of bypass (p < 0.01), hut was still elevated 5–7 hours later (20.5, SD 2.5 percent). The result of the changes in binding was a smaller decline in unbound thiopentone concentration at the onset of bypass to 76.4 (SD 15.7) percent of the prebypass level. Also, unbound levels returned to the prebypass level by the end of bypass, whereas total levels remained low.