Activities of daily living and cardiovascular complications following elective, noncardiac surgery.

BACKGROUND: Algorithms for preoperative cardiac evaluation prior to noncardiac surgery use indices of the metabolic equivalent of activities of daily living (METs). We evaluated METs as a predictor of cardiac complications following elective, noncardiac surgery. METHODS: A study was performed in an outpatient university preadmission center METs were estimated prospectively for 5,939 inpatients admitted for elective, noncardiac surgery who underwent a preanesthetic assessment within two months prior to surgery. Cardiac outcomes were retrieved retrospectively from relational databases. Outcomes included death, myocardial infarction, acute congestive failure, arrhythmias, cardiac arrest, acute ischemia, acute renalfailure, stroke, respiratory failure, severe hypertension, peripheral vascular occlusion, and pericardial effusion. Adverse outcomes were correlated with age, gender, surgical procedure, activities, and the American Society of Anesthesiologist's Physical Status (ASA-PS) using receiver operator characteristic curve analysis. RESULTS: 94 of 5,939 (1.6 percent) patients had cardiac complications; 16 died, six from their cardiac complication. 38.3 percent of complications occurred following vascular surgery. Using a multinomial logistic regression analysis, both age and physical status were highly significant predictors (p < 0.001) but METs was not (p = 0. 793). Receiver operator characteristic (ROC) curves were usedfor predictive value of variables. Area of the curves for age versus cardiac complications and death were 0.814 and 0.782; for physical status, 0.744 and 0.803; for METs, 0.664 and 0.524. CONCLUSIONS: METs are not a reliable index for the prediction of adverse cardiac events following elective, noncardiac surgery. Age and physical status are more predictive. Adverse cardiac outcomes are most frequent following vascular surgery.

Must living renal donors be hospitalized overnight prior to surgery?

To determine whether preoperative intravenous hydration was an important determinant of perioperative safety for the kidney donor or of early allograft function, 21 consecutive living donor transplants were assessed retrospectively. Donors hospitalized overnight received 1008 +/- 169 mL of intravenous fluid during the 8 h prior to operation, compared to no preoperative hydration among a cohort of 15 patients. No differences between intraoperative blood pressures, fluid administration, urine output, or time in the operating room were identified between groups. Postoperative allograft function was not compromised by the lack of hydration. We conclude that living kidney donors can safely undergo elective nephrectomy without prior intravenous hydration.

Anesthesiology.

In suitable candidates undergoing cardiac surgery, inhalation agents and new protocols for postoperative care have facilitated early extubation and reduced levels of intensive care. Volunteers with no prior experience in resuscitation were more successful in maintaining patent airways with the laryngeal mask airway than with the standard face mask and oral airway.

Binding of (3H)prostaglandin E1 to putative receptors linked to adenylate cyclase of cultured cell clones.

A method for assessing the binding of 3H-labeled prostaglandin E1 ([3H]PGE1) to cell membranes has been developed and used to study the interaction of [3H]PGE1 with membranes from cultured mammalian cells. Receptor sites were identified by correlation of the potency of a series of compounds to compete for [3H]PGE1 binding sites and to stimulate adenylate cyclase activity, by correlation of rates of binding and change in enzyme activity, and by the correspondence of [3H]PGE1-binding activity with the presence or absence of PGE1-sensitive adenylate cyclase in several clones. In clone B82, a murine L-cell, [3H]PGE1 binds with an activation energy of 14 kcal/mol to a class of sites with an affinity of 0.5 X 10(8) M-1 and a capacity of 150 fmol/mg of protein. Concentration dependence of adenylate cyclase activation by PGE1 (KD =30 nM) and kinetic analysis of [3H]PGE1 binding (k1 = 4 X 10(6) liters/mol/min, k-1 0.15/min) verify this affinity. Concentration dependence and specificity of binding and activation of adenylate cyclases in neuroblastoma clone N4TG1 and N18TG2 substantiate the method. In several clones that lack PGE1-responsive adenylate cyclase, no specific [3H]PGE1 binding is detectable.

Binding of (125I)iodohydroxybenzylpindolol to putative beta-adrenergic receptors of rat glioma cells and other cell clones.

[125I]Iodohydroxybenzylpindolol, an extremely potent beta-adrenergic antagonist, has been purified to theoretical specific activity (2200 Ci/mmol) and used as a ligand to characterize the beta-adrenergic receptors of cultured rat glioma cells and other cultured cell clones. Appropriate receptor sites were identified by stereoselective competition for binding by a number of adrenergic agonists and antagonists, by correlation between the potency of these compounds to inhibit binding and to affect adenylate cyclase activity, and by correlation of binding with the presence or absence of response to catecholamines (stimulation of adenylate cyclase) in various cell clones. In equilibrium experiments, the dissociation constant for binding of the iodinated ligand to the beta-adrenergic receptor of a clone of rat glioma cells (C6TG1A) was 250 pM; the corresponding value for a clone of human fibroblasts (VA2) was 15 pM. For C6TG1A, KD was verified by analysis of the kinetics of binding: k1 = 10(8) 1/mol/min: k-1 = 0.017/min. This rate of dissociation of ligand from the receptor was also established by study of the rate of activation of adenylate cyclase by isoproterenol after prior equilibration with iodohydroxybenzylpindolol. For VA2 cells, where affinity was higher, the rate of reversal of binding was only 0.0035/min. C6TG1A contained approximately 4000 receptor sites/cell (75 fmol/mg of protein), and these sites appeared to be coupled to adenylate cyclase in a stoichiometric manner. A second site with equal affinity for iodohydroxybenzylpindolol (KD = 250 pM) was also identified in C6TG1A by both kinetic analysis and equilibrium binding studies. While most compounds that interacted with the beta-adrenergic receptor also influenced binding to the second site, the latter did not distinguish between stereoisomers of propranolol, and its affinity for the other compounds tested was poorer.