title: Hypertensive response to thiopental in man during cardiopulmonary bypass.
abstract: We report the effect of 250 mg of sodium thiopental on vascular tone at constant blood flow in 26 patients undergoing cardiopulmonary bypass while the ascending aorta was cross-clamped. Light anaesthesia was effected with fentanyl and enflurane, muscle relaxation with pancuronium. After a latent period of 10.5 +/- 0.7 s there was a hypertensive response of 9.8 +/- 0.5 s duration and of 21.4 +/- 1.7 mmHg (2.8 +/- 0.2 kPa) magnitude; this was followed by hypotension of 39.6 +/- 4.2 s duration and of 18.4 +/- 1.9 mmHg (2.4 +/- 0.3 kPa) magnitude. There was a statistically significant inverse correlation between the hypertension and body temperature (P = 0.005); the time to onset of hypertension correlated directly with pump volume (P = 0.001), weight of the patient (P = 0.03), and cross-clamp time before the drug was given (P = 0.002), and correlated inversely with the serum sodium concentration (P = 0.001). The duration of hypertension was inversely related to the plasma bicarbonate (P = 0.01) and body temperature (P = 0.04). The duration of hypotension was significantly longer in women (P = 0.0001) and was directly related to the duration of cross-clamping (P = 0.0007), to pH (P = 0.0016), and to PCO2 (P = 0.04). We speculate that thiopental induced the hypertensive response due to a potentiation of the vasoconstrictive (local) effect of norepinephrine, and induced the hypotensive response by a central nervous system effect. Thiopental had no apparent effect on venous tone.
mesh_terms: D000768:Anesthesia, General; D000771:Anesthesia, Intravenous; D001794:Blood Pressure / Q000187:drug effects*; D002315:Cardiopulmonary Bypass; D005283:Fentanyl; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000502:physiology; D013874:Thiopental / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D013874:Thiopental; D005283:Fentanyl; D009638:Norepinephrine