Intensive care medicine
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To investigate the changes in respiratory mechanics in patients undergoing cardiac surgery before and after the operation. ⋯ This study shows that (1) respiratory mechanics can be abnormal in patients undergoing cardiac surgery, including expiratory flow limitation; (2) elastance increases and PaO(2) decreases after surgery; (3) simple, noninvasive techniques are available to measure respiratory mechanics in the operating theatre.
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Intensive care medicine · Oct 1999
Case ReportsMyoglobin clearance and removal during continuous venovenous hemofiltration.
Myoglobin has a relatively high molecular weight of 17,000 Da and is poorly cleared by dialysis (diffusion). However, elimination of myoglobin might be enhanced by an epuration modality based on convection for solute clearances. We present a single case of myoglobin-induced renal failure (peak creatine kinase level: 313,500 IU/l) treated by continuous venovenous hemofiltration (CVVH). ⋯ If myoglobin clearance had been maintained at 22 ml/min, 32 l of serum would have been cleared per day. However, the sieving coefficient of myoglobin decreased over time, probably as a consequence of protein coating and/or blood clotting of the hemofilter. Whereas myoglobin can be removed by CVVH, it remains unknown at this point if such a modality, applied early, can alter or shorten the course of myoglobinuric acute renal failure.
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Intensive care medicine · Oct 1999
Clinical TrialVancomycin clearance during continuous venovenous haemofiltration in critically ill patients.
To study the pharmacokinetics of vancoymcin in critically ill patients with acute renal failure treated with continuous venovenous haemofiltration (CVVHF). ⋯ The average sieving coefficient in vitro was 0.73 +/- 0.06, 0.86 +/- 0.11, and 0.80 +/- 0.06 for the PAN 03, 06, and 10 haemofilters, respectively. Changes in the sieving coefficient by increasing the ultrafiltration rate were not clinically significant. The first patient was given a single dose of vancomycin, 1000 mg by intravenous infusion. The following pharmacokinetic data were obtained: apparent volume of distribution (Vd) 55.8 l, terminal half-life time (t(1/2 term)) 15.4 h, total clearance (Cl(tot)) 2.5 l/h, CVVHF clearance (CL(CVVHF, form 1)) 1.4 l/h, and body clearance (Cl(body)) 1.1 l/h. The average sieving coefficient during the study period was 0.89 +/- 0.03. In the second patient, the pharmacokinetics of vancomycin were studied following dose reduction: Vd 41.7 l, (1/2 term) 20.3 h, Cl(tot) 1.4 l/h, Cl(CVVHF, form 1) 1.4 l/h, and Cl(body) < 0.1 l/h. The average sieving coefficient during the study period was 0.88 +/- 0. 03. The cumulative amount of vancomycin removed by means of CVVHF during the 12-h study period was 245 mg in patient 1 and 228 mg in patient 2. CONCLUSIONS++: CVVHF with a PAN 06 haemofilter effectively removed vancomycin in two critically ill patients. The amount of vancomycin removed with CVVHF was about 250 mg per 12 h. A clear difference in body clearance in the two patients was observed. Our dosage recommendation for vancomycin in critically ill patients receiving CVVHF is a loading dose of 15-20 mg/kg followed after 24 h by 250 to 500 mg twice daily with close monitoring of the serum and ultrafiltrate vancomycin concentration.