Creatinine Level as Measures of Renal Function
The identification of preoperative risk factors for adverse outcomes after cardiac surgery is an important component of perioperative care. It helps clinicians provide better informed consent to patients by bringing up specific considerations that could influence outcome. It identifies higher-risk patients requiring special care and in whom new interventions can be developed to improve outcome. Finally, it allows risk-adjusted evaluation of outcome and quality of care Australia viagra Pharmacy. Preoperative renal dysfunction is an important risk factor in cardiac surgery. This has been confirmed repeatedly by strong epidemiologic associations between elevated plasma creatinine levels and poorer outcome after cardiac sur-gery.
Plasma creatinine level is a highly specific marker of renal impairment; however, it may be insensitive to mild and moderate degrees of renal dysfunction because it depends on many nonrenal factors including muscle mass, gender, and metabolism. Creatinine clearance (ClCr) is a better estimate of glomerular filtration rate (GFR). We therefore hypothesized that the association between preoperative renal dysfunction and major postoperative complications would be stronger by using preoperative ClCr instead of plasma creatinine level as a measure of renal function. If this was true, cardiac surgical patients with normal plasma creatinine levels, but decreased ClCr, could be at higher risk of morbidity and mortality than they might appear.
In this study, we estimated ClCr in a large cohort of cardiac surgical patients, using the formula developed by Cockroft and Gault. Previously evaluated in cardiac patients, this simple formula predicts ClCr with acceptable accuracy. To test our hypothesis, we developed preoperative multivariable risk models, using either estimated ClCr or plasma creatinine level as a measure of renal function, and assessed the ability of those models in predicting postoperative renal failure requiring dialysis, and mortality and major morbidity. We further determined the association between renal function and outcome by calculating the adjusted risks of major postoperative complications as the preoperative estimated ClCr decreased, considering separately patients with normal plasma creatinine levels and those with elevated levels.