thiopental and Renal-Insufficiency

We have surgically treated 771 patients for thoracic and thoracoabdominal aortic aneurysms since 1983. Our primary effort has been to develop experimentally validated strategies to reduce paraplegia, renal failure, and mortality in these high-risk patients. This approach has led to a spinal cord protection protocol that has reduced paraplegia risk by 80% (observed/expected ratio = 0.19) with the use of cerebral spinal fluid drainage, moderate hypothermia (31°C-33°C), endorphin receptor antagonist (naloxone), and thiopental burst suppression while optimizing mean arterial pressure (> 90 mm Hg) and cardiac index. The elective mortality rate is 2.80% (17% for acute patients), and with rapid renal cooling for renal protection, only 0.88% required permanent dialysis. These results were achieved without the use of assisted circulation. We have reattached intercostal arteries since 2005 using preoperative magnetic resonance angiographic localization, but it remains unclear whether intercostal reimplantation reduces paraplegia risk, as we had initially proposed. We strongly believe that a consistent anesthetic and postoperative care protocol uniformly built and applied around these principles greatly enhances our surgical outcomes. We also show that improved outcomes with assisted circulation and hypothermic arrest in treatment of thoracoabdominal aortic disease follow similar principles of spinal cord and end-organ protection.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Anesthetics, Intravenous; Aortic Aneurysm, Thoracic; Assisted Circulation; Cerebrospinal Fluid Shunts; Child; Constriction; Female; Heart Arrest, Induced; Hemodynamics; Humans; Hypothermia, Induced; Male; Middle Aged; Naloxone; Narcotic Antagonists; Paraplegia; Postoperative Care; Renal Insufficiency; Replantation; Risk Assessment; Risk Factors; Spinal Cord Ischemia; Suture Techniques; Thiopental; Thoracic Arteries; Treatment Outcome; Vascular Surgical Procedures; Wisconsin; Young Adult

Elderly patients with hyperkalaemia often have low concentrations of plasma renin and aldosterone, perhaps secondary to reduced glomerular filtration and sympathetic insufficiency. The endocrine response to surgical stress and volume expansion during anaesthesia was studied in seven elderly patients with hyperkalaemia (mean age 87.7 +/- SD 5.3 years), 18 elderly patients without hyperkalaemia (86.5 +/- 5.5 years), and 18 younger patients (52.6 +/- 7.2 years) as controls. Base-line values, in hyperkalaemic elderly patients, for plasma renin activity and plasma aldosterone concentration were 0.8 +/- 0.3 ng mL-1 h-1 and 2.8 +/- 0.8 pg mL-1 respectively (significantly lower than in the younger patients), and 287 +/- 42 pg mL-1 for plasma atrial natriuretic peptide levels, which were significantly higher. The plasma renin activity and aldosterone concentrations in elderly patients with hyperkalaemia were at all times lower, but not significantly, than those of the elderly patients without hyperkalaemia. The atrial natriuretic peptide concentrations (351 +/- 48 pg mL-1) in the hyperkalaemic elderly were significantly higher 90 min after induction of anaesthesia than in the normokalaemic elderly (108 +/- 38 pg mL-1). Hormone concentrations in the hyperkalaemic patients did not change during anaesthesia, but plasma atrial natriuretic peptide concentrations increased significantly in the normokalaemic elderly, and plasma renin activity and aldosterone of the younger patients increased significantly during anaesthesia. These results indicate that plasma renin activity, and the concentrations of aldosterone and of atrial natriuretic peptide in elderly patients with hyperkalaemia are unresponsive to surgical stress and volume expansion.

Topics: Adult; Aged; Aged, 80 and over; Aging; Aldosterone; Anesthesia, General; Anesthetics, Inhalation; Anesthetics, Intravenous; Atrial Natriuretic Factor; Femoral Neck Fractures; Follow-Up Studies; Glomerular Filtration Rate; Humans; Hyperkalemia; Isoflurane; Middle Aged; Nitrous Oxide; Plasma Substitutes; Potassium; Renal Insufficiency; Renin; Sodium; Stress, Physiological; Thiopental

The purpose of this work was to investigate the disposition characteristics and pharmacodynamics of a barbiturate, thiopental, in renal dysfunction rats. Normal and renal dysfunction rats were infused with 40 and 20 mg/kg of thiopental, respectively. The quantitative electroencephalographic (EEG) method was used as the surrogate measure of pharmacological response. Signals from two electrodes fitted on the skull of rats were continuously measured, recorded and subjected to off-line analysis. Total amplitude (0.5-29.9Hz) from aperiodic analysis was taken as the EEG parameter. Thiopental concentration in plasma and cerebrospinal fluid (CSF) was assayed by an HPLC method. Steady-state volume of distribution was increased in renal dysfunction rats due to decreased plasma protein binding, while no change in clearance or volume of distribution based on the plasma unbound concentration was observed. Amplitude changes induced by thiopental in both normal and renal dysfunction rats were characterized by the sigmoidal Emax model. The unbound plasma concentration at half maximal effect was lowered by 30% in renal dysfunction rats as compared to the normal rats. In addition to considerable alteration in the pharmacokinetics of thiopental, it was also evident that renal impairment is associated with an increase in apparent pharmacological sensitivity, which is related to affinity.

Topics: Analysis of Variance; Animals; Electroencephalography; Hypnotics and Sedatives; Male; Rats; Rats, Wistar; Renal Insufficiency; Thiopental