Does electronic clinical microbiology results reporting influence medical decision making: a pre- and post-interview study of medical specialists

Background  

Clinicians view the accuracy of test results and the turnaround time as the two most important service aspects of the clinical microbiology laboratory. Because of the time needed for the culturing of infectious agents, final hardcopy culture results will often be available too late to have a significant impact on early antimicrobial therapy decisions, vital in infectious disease management. The clinical microbiologist therefore reports to the clinician clinically relevant preliminary results at any moment during the diagnostic process, mostly by telephone. Telephone reporting is error prone, however. Electronic reporting of culture results instead of reporting on paper may shorten the turnaround time and may ensure correct communication of results. The purpose of this study was to assess the impact of the implementation of electronic reporting of final microbiology results on medical decision making.     

The effect of plasma caeruloplasmin levels on the sensitivity for activated protein C

The effect of caeruloplasmin levels on the sensitivity for activated protein C (APC), measured by a clotting assay based on the activated partial thromboplastin time, was investigated in a large group of healthy individuals without factor V Leiden. A modest inverse association between caeruloplasmin and normalized APC sensitivity ratio was found (regression coefficient beta = -0.33 x 10-2; 95% confidence interval, -0.42 x 10-2 to -0.24 x 10-2). After adjustment for sex and oral contraceptive use, this association weakened (beta = -0.19 x 10-2; 95% CI: -0.34 x 10-2 to -0.05 x 10-2). After additional adjustment for factor VIII levels, which are known to influence the assay, the effect of caeruloplasmin on APC sensitivity completely disappeared.     

Aminoglycoside-associated hypomagnesaemia in children with cystic fibrosis

Hypomagnesaemia in children with cystic fibrosis (CF) is under-recognized. We report a child with CF who developed significant hypomagnesaemia following intravenous (i.v.) treatment with aminoglycosides for exacerbations of Pseudomonas aeruginosa infection. Three additional cases have also been observed. Investigations in two patients have revealed excessive renal loss of magnesium. It is postulated that renal tubular damage secondary to the cumulative effects of repeated courses of aminoglycosides resulted in hypomagnesaemia, and we suggest screening for this problem by monitoring serum magnesium regularly in all patients with CF receiving multiple courses of aminoglycosides.     

Pharmacokinetics of Bupivacaine during Postoperative Epidural Infusion: Enantioselectivity and Role of Protein Binding

Background: Changing plasma protein concentrations may affect the protein binding and pharmacokinetics of drugs in the postoperative period. This study examined the effect of postoperative increases (in response to surgery) in plasma [alpha]1-acid-glycoprotein (AAG) concentrations on the plasma concentrations of the enantiomers of bupivacaine during continuous epidural infusion of racemic bupivacaine for postoperative pain relief.

Methods: Six patients scheduled for total hip surgery with combined epidural and general anesthesia received a bolus dose of bupivacaine (65 mg) followed by constant-rate (8 ml/h) epidural infusion of 2.5 mg/ml bupivacaine for 48 h. Total and unbound plasma concentrations of the enantiomers of bupivacaine and plasma AAG concentrations during the 48-h epidural infusion were determined.

Results: Total plasma concentrations of the enantiomers of bupivacaine increased steadily during the infusion (P < 0.0001), whereas unbound concentrations did not change after 12 h (P > 0.1). Total plasma concentrations of S (-)-bupivacaine were higher than those of R (+)-bupivacaine (P < 0.02), whereas unbound concentrations of S (-)-bupivacaine were lower than those of R (+)-bupivacaine (P < 0.002). AAG concentrations initially decreased, but thereafter increased steadily (P < 0.0001). Consequently, free fractions of the enantiomers initially increased and then decreased with time (P = 0.0002). Free fractions of S (-)-bupivacaine were smaller than those of R (+)-bupivacaine (P = 0.0003).     

Combining salicylate and enalapril in patients with coronary artery disease and heart failure.

OBJECTIVE--To study the effects of adding a salicylate to the angiotensin converting enzyme inhibitor enalapril in patients with heart failure due to coronary artery disease. DESIGN--Double blind, crossover study for three days in hospital followed by an extended similar study outside hospital over two months of once daily enalapril plus salicylate and enalapril plus placebo. SETTING--Tertiary referral centre. PATIENTS--20 patients with heart failure due to myocardial infarction (New York Heart Association class II or III) and an ejection fraction less than 0.40. Twelve patients completed the two parts of the study. MAIN OUTCOME MEASURES--Blood pressure, plasma converting enzyme activity; plasma angiotensin II and noradrenaline concentrations; excretion of metabolites of renal and systemic prostanoids. RESULTS--The unloading effect of first and second dose of enalapril in the morning lasted only during the day; in the extended study it lasted 24 hours because of the drug''s accumulation. Converting enzyme inhibitors attenuate the breakdown of bradykinin and therefore enhance prostaglandin E2 synthesis mediated by bradykinin. Evidence was found of such a prostaglandin E2 mediated contribution to ventricular unloading by enalapril, which was blocked by salicylate. The contribution, however, was small and variable, and salicylate addition had on average no significant de-unloading effect during the day. Unloading was abolished in only three of the 20 patients in the short term study and in one of the 12 in the extended study. At night, when other effects of enalapril on blood pressure had waned and the bradykinin induced effect persisted, salicylate significantly reduced the remaining small unloading effect. No effect was seen of salicylate addition on reversal of remodelling. Enalapril reduced angiotensin II induced synthesis of systemic and renal prostaglandin I2 and thromboxane A2, initially only during the day, but later also at night. It thereby masked suppression of thromboxane A2 synthesis by salicylate, which is the effect to which reinfarct prevention by salicylate is attributed. CONCLUSION--The risk is low that salicylate will substantially reduce the benefit of enalapril in patients with heart failure by de-unloading the ventricle. Like other effects induced by bradykinin significant de-unloading occurs in only a minority of the patients. In the presence of enalapril, however, salicylate will probably not be as effective as expected in reducing reinfarction risk, because enalapril already reduces thromboxane A2 synthesis effectively in patients with heart failure and no further reduction by salicylate was found.     

Automated method for the determination of 5'-nucleotidase in serum by continuous flow analysis

The manual method of Persijn & Van der Slik (J. Clin. Chem. Clin. Biochem. 6, 441-446 (1968): 7, 493-497 (1969); 8, 398-402 (1970) for the determination of serum 5'-nucleotidase has been adapted to the Auto-Analyzer II System. In the Auto-Analyzer II, the incubation temperature for the enzyme reactions is 37 degrees C, and the effective sample speed is 30/h, at a sample/wash ratio of 2:1. There is good agreement and correlation between the manual method and the Auto-Analyzer II method (equation of regression line: y = x + 0.6, correlation coefficient = 0.988; the normal range is 2.9-10.5 U/l for both methods). In routine use, within-run and between-day reproducibility are considerably smaller for the Auto-Analyzer II than for the manual method, especially when large numbers of samples are assayed.     

Comparison of intermethod analytical variability of patient sera and commercial quality control sera.

The intermethod analytical variability of 59 commercially available control sera was compared with that of patient sera. For this purpose, patient and control sera were assayed with respect to ten constituents (albumin, alkaline phosphatase, alpha-amylase, cholesterol, glucose, iron, lactate dehydrogenase, creatinine, protein, and urea), each with two analytical methods. Only 6 of the 59 control materials showed an intermethod analytical variability comparable to that of the patient sera for all of the determinations. The use of patient sera for the calibration of routine analytical methods is recommended.