Anesthesiology
-
Randomized Controlled Trial Comparative Study Clinical Trial
Treatment of hypotension after hyperbaric tetracaine spinal anesthesia. A randomized, double-blind, cross-over comparison of phenylephrine and epinephrine.
Despite many advantages, spinal anesthesia often is followed by undesirable decreases in blood pressure, for which the ideal treatment remains controversial. Because spinal anesthesia-induced sympathectomy and management with a pure alpha-adrenergic agonist can separately lead to bradycardia, the authors hypothesized that epinephrine, a mixed alpha- and beta-adrenergic agonist, would more effectively restore arterial blood pressure and cardiac output after spinal anesthesia than phenylephrine, a pure alpha-adrenergic agonist. ⋯ Epinephrine management of tetracaine spinal-induced hypotension increases heart rate and cardiac output and restores systolic arterial pressure but does not restore mean and diastolic blood pressure. Phenylephrine management of tetracaine spinal-induced hypotension decreases heart rate and cardiac output while restoring systolic, mean, and diastolic blood pressure.
-
Randomized Controlled Trial Clinical Trial
Urine and plasma catecholamine and cortisol concentrations after myocardial revascularization. Modulation by continuous sedation. Multicenter Study of Perioperative Ischemia (McSPI) Research Group, and the Ischemia Research and Education Foundation (IREF).
Cardiopulmonary bypass is associated with substantial release of catecholamines and cortisol for 12 or more h. A technique was assessed that may mitigate the responses with continuous 12-h postoperative sedation using propofol. ⋯ Cardiopulmonary bypass graft surgery is associated with substantial increases in plasma and urine catecholamine and cortisol concentrations, which persist for 12 or more h. This hormonal response may be mitigated by a technique of intensive continuous 12-h postoperative sedation with propofol, which is associated with a decrease in tachycardia and hypertension and an increase in hypotension.
-
Nitric oxide (NO) has been reported to play an important role in isoflurane-induced cerebral hyperemia in vivo. In the brain, there are two constitutive isoforms of NO synthase (NOS), endothelial NOS (eNOS), and neuronal NOS (nNOS). Recently, the mutant mouse deficient in nNOS gene expression (nNOS knockout) has been developed. The present study was designed to examine the role of the two constitutive NOS isoforms in cerebral blood flow (CBF) response to isoflurane using this nNOS knockout mouse. ⋯ In nNOS knockout mice, the cerebral hyperemic response to isoflurane is preserved by compensatory mechanism(s) that is NO-independent at 2.4 vol%, although it may involve eNOS at 1.2 and 1.8 vol%. It is suggested that in wild-type mice, eNOS and nNOS contribute to isoflurane-induced increase in rCBF. At lower concentrations (1.2 and 1.8 vol%), eNOS may be involved, whereas at 2.4 vol%, nNOS may be involved.
-
Epidural catheter movement has been noted with change of patient position and can result in inadequate anesthesia. This study was designed to measure movement and to develop a technique that minimizes catheter displacement. ⋯ Epidural catheters moved a clinically significant amount with reference to the skin in all BMI groups as patients changed position. If catheters had been secured to the skin before position change, many would have been pulled partially out of the epidural space. To minimize the risk of catheter displacement, particularly in obese patients, we recommend that multiorificed catheters be inserted at least 4 cm into the epidural space and that patients assume the sitting upright or lateral position before securing the catheter to the skin.