Implication of Haemodiafiltration Flow Rate on Amikacin Pharmacokinetic Parameters in Critically Ill Patients.

BACKGROUND: To analyse the effect of haemodiafiltration (CVVHDF) flow rate on amikacin pharmacokinetics and blood concentrations. METHODS: Prospective observational study. Patients receiving CVVHDF and amikacin treatment were included. Pharmacokinetic parameters were calculated using Bayesian analysis. Spearman correlation test was used in order to assess the influence of CVVHDF flux on amikacin minimum concentration (Cmin) and plasma clearance. RESULTS: Thirty patients undergoing CVVHDF procedures were included. The treatment with amikacin started at an initial mean dose of 12.4 (4.1) mg/kg/day. An association between the flow rate and Cmin value (r = 0.261; p = 0.161) and plasma clearance was found (r = 0.268; p = 0.152). Four patients (13.3%) were not able to achieve peak concentration over MIC value higher than 8. In 4 patients, amikacin had to be discontinued due to a high Cmin value. CONCLUSIONS: Amikacin clearance in patients with CVVHDF is affected by the flow rate used. Therefore, CVVHDF dose should be taken into account when dosing amikacin.

Vasopressin antagonist efficacy and safety in volume-overloaded critically ill patients: a new therapeutic alternative.

Objectives: To assess tolvaptan's efficacy and safety in critical care patients with volume overload. Methods: Prospective observational study. Twenty-eight patients in the recovery phase from multiple organ failure and with volume overload refractory to conventional therapy treated with tolvaptan were included. Results: Patients received an initial daily dose of 3.75 (n=1), 7.5 (n=8) and 15 (n=19) mg of tolvaptan. Median treatment duration was 2 days (range: 1 to 12). All patients presented an increase in 24 hours diuresis after the first dose (median increase from baseline (IQR)=1114 (285-1943) mL), with a median net daily fluid loss of 1007 mL (456-2380) mL after 24 hours. High diuretic efficacy (daily fluid loss higher than 0.5 L with tolvaptan first dose) was detected in 18 patients (64.3%). Initial hyponatraemia was present in 16 (57.1%) patients, while overly rapid correction with tolvaptan treatment occurred in two patients without clinical consequences. Two patients presented hypophosphataemia after treatment. Conclusion: Tolvaptan is an effective therapeutic option in critically ill patients with volume overload refractory to conventional diuretics. Further studies are required to evaluate its safety profile and its effect on short-term outcomes and mortality.

Individualised antimicrobial dosing in critically ill patients undergoing continuous renal replacement therapy: focus on total drug clearance.

BACKGROUND: Continuous renal replacement therapy (CRRT) is common practice in critical care patients with acute renal failure. OBJECTIVES: To evaluate the adequacy of antimicrobial doses calculated based on the total drug clearance and dose recommended by different guides in critically ill patients undergoing CRRT. METHODS: Retrospective observational study. Patients admitted to a critical care unit during May 2014 to May 2016 and subjected to CRRT were included. The recommended dose was established as the product of the usual dose of the drug by total drug clearance. RESULTS: 177 antimicrobial agents, used in 64 patients were analysed; 45 (25.4%) antimicrobials were given in an insufficient dose (<20%) according to the theoretical calculation. Following the recommendations in the revised guidelines, between 10% and 20% of antimicrobials were given in insufficient doses. A higher success rate of treatment in those patients not receiving a low drug dosage was seen (35.2% vs 24.0%). CONCLUSIONS: There is a great disparity between the antimicrobial dose prescribed, recommended and calculated based on drug clearance in critically ill patients undergoing CRRT.