21 Sep 08
Posted in Acid-Base disorders, Fluid management at 21:36 by Laci
By J M Handy and N Soni
Br. J. Anaesth. 2008;101:141-150
The advent of balanced solutions for i.v. fluid resuscitation and replacement is imminent and will affect any specialty involved in fluid management. Part of the background to their introduction has focused on the non-physiological nature of ‘normal’ saline solution and the developing science about the potential problems of hyperchloraemic acidosis. This review assesses the physiological significance of hyperchloraemic acidosis and of acidosis in general. It aims to differentiate the effects of the causes of acidosis from the physiological consequences of acidosis. It is intended to provide an assessment of the importance of hyperchloraemic acidosis and thereby the likely benefits of balanced solutions.
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Posted in Anesthesia, Pre-operatie evaluation at 21:35 by Laci
By J W Sear, J W Giles, G Howard-Alpe and P Foëx
Br. J. Anaesth. 2008;101:135-138
In the early days of patients presenting for surgery while on beta-blockers, it was customary to stop their administration 2 weeks before elective surgery because of the perceived risk of cardiovascular collapse that could result from blockade of compensatory mechanisms. This view was supported by mostly anecdotal evidence, and seemed illogical as surgery constitutes a high stress situation during which the heart may need to be protected by blockade from the effects of exaggerated sympathetic activity. In 1973, the first detailed haemodynamic study of beta-blockade in surgical patients showed that beta-blockade was compatible with anaesthesia and surgery, reduced the risk of hypertension on laryngoscopy and intubation, and decreased the incidence of both ventricular arrhythmias and myocardial ischaemia.
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18 Sep 08
Posted in Critical Care, Glucose control at 19:37 by Laci
By R S Wiener, D C Wiener, R J Larson
JAMA 2008;300:933-944.
The American Diabetes Association and Surviving Sepsis Campaign recommend tight glucose control in critically ill patients based largely on 1 trial that shows decreased mortality in a surgical intensive care unit. Because similar studies report conflicting results and tight glucose control can cause dangerous hypoglycemia, the data underlying this recommendation should be critically evaluated.
Objective
To evaluate benefits and risks of tight glucose control vs usual care in critically ill adult patients.
Data Sources
MEDLINE (1950-2008), the Cochrane Library, clinical trial registries, reference lists, and abstracts from conferences from both the American Thoracic Society (2001-2008) and the Society of Critical Care Medicine (2004-2008).
Study Selection
We searched for studies in any language in which adult intensive care patients were randomly assigned to tight vs usual glucose control. Of 1358 identified studies, 34 randomized trials (23 full publications, 9 abstracts, 2 unpublished studies) met inclusion criteria.
Data Extraction and Analysis
Two reviewers independently extracted information using a prespecified protocol and evaluated methodological quality with a standardized scale. Study investigators were contacted for missing details. We used both random- and fixed-effects models to estimate relative risks (RRs).
Results
Twenty-nine randomized controlled trials totaling 8432 patients contributed data for this meta-analysis. Hospital mortality did not differ between tight glucose control and usual care overall (21.6% vs 23.3%; RR, 0.93; 95% confidence interval [CI], 0.85-1.03). There was also no significant difference in mortality when stratified by glucose goal ([1] very tight: ≤110 mg/dL; 23% vs 25.2%; RR, 0.90; 95% CI, 0.77-1.04; or [2] moderately tight: <150 mg/dL; 17.3% vs 18.0%; RR, 0.99; 95% CI, 0.83-1.18) or intensive care unit setting ([1] surgical: 8.8% vs 10.8%; RR, 0.88; 95% CI, 0.63-1.22; [2] medical: 26.9% vs 29.7%; RR, 0.92; 95% CI, 0.82-1.04; or [3] medical-surgical: 26.1% vs 27.0%; RR, 0.95; 95% CI, 0.80-1.13). Tight glucose control was not associated with significantly decreased risk for new need for dialysis (11.2% vs 12.1%; RR, 0.96; 95% CI, 0.76-1.20), but was associated with significantly decreased risk of septicemia (10.9% vs 13.4%; RR, 0.76; 95% CI, 0.59-0.97), and significantly increased risk of hypoglycemia (glucose ≤40 mg/dL; 13.7% vs 2.5%; RR, 5.13; 95% CI, 4.09-6.43).
Conclusion
In critically ill adult patients, tight glucose control is not associated with significantly reduced hospital mortality but is associated with an increased risk of hypoglycemia.
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17 Sep 08
Posted in Anesthesia, Pre-operatie evaluation at 12:29 by Laci
By T H Lee, E R Marcantonio, C M Mangione, E J Thomas, C A Polanczyk, F Cook, D J Sugarbaker et al
Circulation 1999;100:1043-1049
Cardiac complications are important causes of morbidity after noncardiac surgery. The purpose of this prospective cohort study was to develop and validate an index for risk of cardiac complications.
Methods and Result
We studied 4315 patients aged >=50 years undergoing elective major noncardiac procedures in a tertiary-care teaching hospital. The main outcome measures were major cardiac complications. Major cardiac complications occurred in 56 (2%) of 2893 patients assigned to the derivation cohort. Six independent predictors of complications were identified and included in a Revised Cardiac Risk Index: high-risk type of surgery, history of ischemic heart disease, history of congestive heart failure, history of cerebrovascular disease, preoperative treatment with insulin, and preoperative serum creatinine >2.0 mg/dL. Rates of major cardiac complication with 0, 1, 2, or >=3 of these factors were 0.5%, 1.3%, 4%, and 9%, respectively, in the derivation cohort and 0.4%, 0.9%, 7%, and 11%, respectively, among 1422 patients in the validation cohort. Receiver operating characteristic curve analysis in the validation cohort indicated that the diagnostic performance of the Revised Cardiac Risk Index was superior to other published risk-prediction indexes.
Conclusion
In stable patients undergoing nonurgent major noncardiac surgery, this index can identify patients at higher risk for complications. This index may be useful for identification of candidates for further risk stratification with noninvasive technologies or other management strategies, as well as low-risk patients in whom additional evaluation is unlikely to be helpful.
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