Hsin Lin

Daily vancomycin dose requirements as a continuous infusion in obese versus non-obese SICU patients

BackgroundLimited data are available assessing vancomycin concentrations in obese critically ill patients. Currently, there are no studies evaluating dosing requirements in this population who receive vancomycin administered as a continuous infusion (CI). The aim of this study was to assess whether there was a difference in the weight-based maintenance dose required to reach a therapeutic vancomycin concentration at 24 hours when given as a CI in obese versus non-obese critically ill patients.MethodsA retrospective cohort study of adult obese patients admitted to the SICU between 2013 and 2015 receiving a vancomycin CI (CIV), and with 24-hour serum measurements were included. Obese patients (body mass index (BMI) ≥35 kg/m2) were matched with non-obese patients (BMI <30 kg/m2) based on renal function, age and acute physiology and chronic health evaluation (APACHE)-II score at admission. All patients in this study received a loading dose of 25 mg/kg then a maintenance dose based on renal function according to the protocol. The study was approved by the Institutional Review Board. The primary outcome was the weight-based total daily maintenance dose required to achieve a vancomycin level of 20 mg/L. The secondary endpoints included the achievement of a therapeutic level at 24 hours.ResultsTwenty-six matched pairs of patients met the inclusion criteria. Of these, 17 pairs had preserved renal function and 9 pairs required continuous venovenous hemofiltration. Mean BMI was 40.9 kg/m2 in obese and 24.8 kg/m2 in non-obese patients. To achieve a vancomycin concentration of 20 mg/L, the weight-based daily maintenance dose in obese patients was 25.6 mg/kg versus 43.8 mg/kg in non-obese patients (p <0.01). Therapeutic 24-hour levels were achieved in 24/26 obese versus 23/26 no-obese patients (p = 0.63). Mean 24-hour vancomycin level was 20.3 ± 3.81 mcg/ml in obese compared to 20.03 ± 3.79 mcg/ml in non-obese patients (p = 0.77). Mean daily maintenance doses required to achieve a level of 20 mcg/ml were 2961 ± 1670 mg in obese compared to 3189 ± 1600.69 mg in non-obese (p = 0.61).ConclusionsThe results of our study suggest that critically ill obese patients treated with CIV required a significantly lower maintenance dose per unit of body weight than non-obese patients to achieve the same target level.

Vancomycin continuous infusion versus intermittent infusion during continuous venovenous hemofiltration: slow and steady may win the race

BackgroundVancomycin during continuous venovenous hemofiltration (CVVH) is either administered by intermittent infusion (II) or continuous infusion (CI). In this patient population, the best method to rapidly achieve target serum concentrations of 15 mcg/ml to 25 mcg/ml remains to be elucidated. We hypothesized that CI would achieve a target serum level of 15 mcg/ml to 25 mcg/ml within 24 h of the initiation of therapy more consistently than II.MethodsA retrospective cohort study of adult patients admitted to the intensive care unit (ICU) between 2011 and 2014 receiving intravenous vancomycin with 24-hour serum level while on CVVH was included. Patients were excluded from this review if they had residual renal function during CVVH, were concomitantly on extracorporeal membrane oxygenation, or if the first dose of vancomycin was received six or more hours prior to the initiation of CVVH. The primary outcome was the achievement of a therapeutic level of 15mcg/ml to 25 mcg/ml by 24 hours.ResultsFifty-nine patients met the inclusion criteria and 14 received CI and 45 in II. Therapeutic 24-hour levels were achieved in 14/14 versus 2/45 in CI and II, respectively (p < 0.001). Mean 24-hour vancomycin levels were 20.35 ± 2.78 mcg/ml for CI compared to 9.7 ± 3.52 mcg/ml for II (p < 0.001). Mean loading dose was 26.65 ± 3.06 mg/kg for CI compared to 17.58 ± 5.72 mg/kg for II (p < 0.001). Daily maintenance doses were 15.66 ± 6.26 mg/kg for CI compared to 17.28 ± 4.96 mg/kg for II (p = 0.339). In the subgroup of 27 patients who received vancomycin-loading dose >20 mg/kg, mean 24-hour levels were 20.35 ± 2.78 mcg/ml for CI versus 11.8 ± 2.7 mcg/ml for II (p < 0.001). No significant differences were found between patients in the two groups with respect to CVVH rate and length of CVVH prior to vancomycin administration.ConclusionsThe results of our study suggest that critically ill patients on CVVH treated with CI achieved the target level faster than II and consistently keep the vancomycin level within target range.

Impact of a Multidisciplinary Bundle on Time to Antibiotic Administration in Septic SICU Patients.

Purpose: The goal of this study was to investigate barriers to timely antibiotic administration in septic surgical intensive care unit (SICU) patients and examine the impact of a multidisciplinary bundle on the time from prescription to antibiotic administration. Methods: This was a pre- and postintervention study that consisted of 3 phases: (1) preintervention phase, retrospective evaluation of data, (2) intervention implementation, and (3) a postintervention phase. A nurse survey was conducted to identify barriers to rapid antibiotic administration during phase 1. Based on this survey, multidisciplinary interventions included adding antibiotics to the automatic dispensing cabinet, educating monthly staff, and providing an antibiotic dosing table to all prescribers, which is attached to the computer workstations. Our multidisciplinary team consisted of the ICU medical directors, nurse managers, nurses, a critical care fellow, and ICU pharmacists. Results: The percentage of antibiotics that were received within 60 minutes was 26.3% in the pregroup versus 84.0% in the postgroup (P < .001). The mean total prescriber to patient time was 110 minutes in the pregroup versus 58.4 minutes in the postgroup (P < .001). Conclusion: We achieved a higher rate of timely antibiotic administration among septic SICU patients by implementing process changes based on barriers identified by the nurses.

Prospective evaluation of a continuous infusion vancomycin dosing nomogram in critically ill patients undergoing continuous venovenous haemofiltration

Objectives The most optimal method of attaining therapeutic vancomycin concentrations during continuous venovenous haemofiltration (CVVH) remains unclear. Studies have shown continuous infusion vancomycin (CIV) achieves target concentrations more rapidly and consistently when compared with intermittent infusion. Positive correlations between CVVH intensity and vancomycin clearance (CLvanc) have been noted. This study is the first to evaluate a CIV regimen in patients undergoing CVVH that incorporates weight-based CVVH intensity (mL/kg/h) into the dosing nomogram. Methods This was a prospective, observational study of patients undergoing CVVH and receiving CIV based on the nomogram. The primary outcome was achievement of a therapeutic vancomycin concentration (15-25 mg/L) at 24 h. Secondary outcomes included the achievement of therapeutic concentrations at 48 and 72 h. Results The nomogram was analysed in 52 critically ill adults. Vancomycin concentrations were therapeutic in 43/52 patients (82.7%) at 24 h. Of the nine patients who were not therapeutic at 24 h, seven were supratherapeutic and two were subtherapeutic. The mean (SD) concentration was 20.1 (4.2)  mg/L at 24 h, 20.7 (3.7) mg/L at 48 h and 21.9 (3.5)  mg/L at 72 h. Patients with CVVH intensity >20 mL/kg/h experienced higher CLvanc at 24 h compared with patients with CVVH intensity <20 mL/kg/h (3.1 versus 2.6 L/h; P = 0.013). Conclusions By incorporating CVVH intensity into the CIV dosing nomogram, the majority of patients achieved therapeutic concentrations at 24 h and maintained them within range at 48 and 72 h. Additional studies are required to validate this nomogram before widespread implementation may be considered.

Randomized controlled trial of different aspirin regimens for reduction of niacin-induced flushing

Purpose Results of a study to test the hypothesis that taking niacin simultaneously with different forms of aspirin would reduce the occurrence of niacin‐induced flushing are reported. Methods Traditionally, taking enteral absorbed aspirin 30 minutes before a niacin dose has been shown to reduce flushing by 30–50% relative to nonuse of aspirin. The objective of the study was to evaluate the efficacy of enteral absorbed and orally dissolved aspirin, taken at the same time as niacin, in reducing the frequency of moderate‐to‐severe flushing. In a prospective, double‐blind, placebo‐controlled crossover trial, healthy adult male and female volunteers were asked to take aspirin or a placebo (both agents were taken in both orally dissolved and swallowed formulations) immediately before niacin administration. Subjects then self‐evaluated flushing symptoms on a validated scale. Results Simultaneous administration of swallowed aspirin and niacin reduced moderate‐to‐severe flushing events by a mean of 36.1%, from 2.35 to 1.5 events per subject (p = 0.003), relative to event rates with use of niacin alone. In a subset of subjects who had experienced moderate‐to‐severe flushing symptoms despite taking swallowed aspirin, flushing in response to subsequent niacin use was decreased by 20.5% (p = 0.05) with coadministration of orally dissolved aspirin and by 18.0% with a regimen containing both orally dissolved and swallowed aspirin (p = 0.03). Conclusion Novel regimens of niacin and aspirin, including orally dissolved aspirin, were effective in reducing niacin‐induced flushing in a small sample of healthy adult volunteers.