thiopental and Pulmonary-Embolism

The vascular response to intravenous thiopental in patients on cardiopulmonary bypass during deep hypothermia was examined.. This was a prospective observational study.. A university teaching hospital.. Twenty-one consecutive adult patients undergoing pulmonary thromboendarterectomy during which deep hypothermic circulatory arrest was instituted.. Immediately before circulatory arrest, each patient was administered a 500-mg dose of thiopental intravenously. Arterial blood pressure was monitored and recorded by using a femoral artery catheter and serum electrolytes, acid-base status and arterial hematocrit were determined immediately before the administration of thiopental.. Thiopental was associated with a dose-related increase in mean arterial pressure of 32 +/- 11 mmHg (p < 0.0001). Thiopental also resulted in an increase in arterial pH of 0.08 +/- 0.03. A positive correlation between the magnitude of the pH change and the magnitude of the hypertensive response was suggested but did not reach statistical significance (p = 0.066). Of the other factors investigated, only serum-ionized calcium had a statistically significant association with the vascular response in that higher ionized calcium was associated with less hypertensive response (p = 0.014).. The administration of thiopental to deeply hypothermic patients during cardiopulmonary bypass is associated with a dramatic increase in mean arterial blood pressure. The mechanism responsible for this vasoconstrictive response may involve thiopental's potentiation of the effects of norepinephrine in the peripheral vasculature.

Topics: Adult; Aged; Anesthetics, Intravenous; Blood Pressure; Cardiopulmonary Bypass; Circulatory Arrest, Deep Hypothermia Induced; Dose-Response Relationship, Drug; Female; Femoral Artery; Follow-Up Studies; Humans; Injections, Intravenous; Male; Middle Aged; Prospective Studies; Pulmonary Embolism; Thiopental; Treatment Outcome

To examine the effects of a bolus injection of the precipitate formed by thiopentone and vecuronium on the pharmacokinetic behaviour of thiopentone, cardiopulmonary physiology, and lung histology.. Of 16 female rabbits (2.9 to 3.1 kg), eight were injected with a precipitate formed by a mixture of 5 mg.kg-1 thiopentone and 0.67 mg.kg-1 vecuronium via the external jugular vein. Eight control rabbits were injected with 5 mg.kg-1 thiopentone alone. Plasma thiopentone concentration, systolic arterial pressure and PaO2 were measured for 60 min after injection. Histological changes in the lungs were evaluated at one and 60 min.. Maximum blood thiopentone concentration in the precipitate group was lower than in the control group (12.9 +/- 4.5 vs 17.0 +/- 1.6 micrograms.ml, P < 0.05), although the half-life of thiopentone in the precipitate group was longer (32.3 +/- 8.5 vs 21.7 +/- 8.2 min, P < 0.05) and the area under the time concentration curve was similar between the two groups. However, the mean residence time was 28% longer in the precipitate group than in controls (P < 0.05). The PaO2 was lower in the precipitate group than in controls one minute after injection (431 +/- 27 vs 464 +/- 18 mmHg, P < 0.05) but not subsequently. Histologically, crystals (30-150 microns in diameter) obstructed small arteries in the lungs at one minute but not at 60 min after injection.. Intravenous injection of precipitate causes pulmonary microembolism, with a small transient decrease in PaO2.

Topics: Anesthetics, Intravenous; Animals; Chemical Precipitation; Female; Neuromuscular Nondepolarizing Agents; Pulmonary Embolism; Rabbits; Thiopental; Vecuronium Bromide

Topics: Anesthesia, General; Female; Halothane; Humans; Hysterectomy; Intraoperative Complications; Middle Aged; Nitrous Oxide; Pulmonary Embolism; Thiopental

Topics: Anesthesia, Inhalation; Atropine; Biopsy; Female; Halothane; Humans; Iliac Vein; Infant; Liver Neoplasms; Male; Neoplasm Metastasis; Nitrous Oxide; Pulmonary Artery; Pulmonary Embolism; Thiopental; Urography; Vaginal Neoplasms; Vena Cava, Inferior

Topics: Anesthesia; Embolism; Humans; Phlebitis; Pulmonary Embolism; Sodium; Thiopental