Clinical audit of gentamicin use by Bayesian pharmacokinetic approach in critically ill children.

INTRODUCTION: Critically ill children tend to have altered gentamicin pharmacokinetics (PK); and so we carried out an audit of gentamicin use using the estimated peak concentrations (Cmax), trough concentrations (Cmin) and area-under-the-concentration-time curve (AUCs) by Bayesian approach. METHODS: Critically ill children with at least one serum gentamicin concentrations available were recruited. We used multiple models Bayesian adaptive control to estimate Cmax, and AUC0-t following each dose. Pediatric risk, injury, failure, loss, end stage renal disease (pRIFLE) criteria was used to identify the incidence of acute kidney injury (AKI). RESULTS: Seventy-three children (961 doses and 143 concentrations) were analysed. AUC0-24 was observed to be higher in earlier age groups with a steady decline in older children. Similar changes were observed in Cmax, Cmin and AUC0-24 at steady state. Significantly higher proportions of children in the other age groups were estimated to have Cmax between 5 and 10 mg/L compared to neonates. Neonates had a higher risk of Cmax above 10 mg/L. Patients with augmented renal clearance exhibited lower AUC0-24 and reduced proportion achieving the target AUC0-24 levels. Nearly one-third of children were observed to meet the pRIFLE criteria for AKI. CONCLUSION: We observed higher initial doses and peak concentrations of gentamicin in neonates and infants compared to older age groups in critically ill children. Uniformity in the paediatric-specific standard treatment guidelines for gentamicin is the need of the hour.

Drug utilisation in adult, paediatric and neonatal intensive care units, with an emphasis on systemic antimicrobials.

INTRODUCTION: Critically ill adults, children and neonates receive drugs that are often administered parenterally and in infusions. Considering patient illness severity, empirical broad-spectrum antimicrobials are commonly used. We conducted the present study to evaluate the drug use in this population, with a special focus on antimicrobials. MATERIAL AND METHODS: A prospective cross-sectional study was implemented in adult, paediatric and neonatal intensive care units. Various prescribing and supplemental indicators were used for drug comparisons. The World Health Organisation's list of essential drugs, the national drug formulary and critically important antimicrobial drugs were assessed. Proportions and median (range) were used to represent categorical and numerical values. RESULTS: Four hundred and ninety-six critically ill patients were enrolled in the study, with 5,636 prescribed drugs used for 31,993 patient-days. Critically ill adults received significantly more drugs compared to children and the neonatal population (11 [8-16], 9 [6-17] and 5 [3-12] respectively). Critically ill neonates received significantly fewer of the drugs listed in the national formulary compared to older children and adults (94.1% [10.1], 92.4% [32.4] and 80.1% [20.4]). Critically ill neonates received fewer antimicrobials (82% compared to 91.3% in adults and 98% in children). Furthermore, critically ill adults received more broad-spectrum antimicrobials compared to neonates. Prolonged empirical antimicrobial use was observed more in critically ill children (52%) compared to adults (29.8%). A large majority of the antimicrobials were critically important for 87.7%, 83.9% and 86.5% of patients in the adult, paediatric and neonatal intensive care units. CONCLUSIONS: We observed significant differences in terms of drug classes predominantly used in various age groups of critically ill patients, particularly regarding the nature and type of antimicrobial drugs and the duration of antimicrobial therapy.

Possible effects of excipients used in the parenteral drugs administered in critically ill adults, children, and neonates.

BACKGROUND: Critically ill patients receiving parenteral drugs are at an increased risk of exposure to various excipients administered simultaneously and at increased amounts. Hence, we carried out the present study. RESEARCH DESIGN AND METHODS: Patients admitted in the adult, pediatric, and neonatal intensive care units were recruited following their consent. Details on their demographics, diagnoses, and drugs administered and the excipients were collected. RESULTS: Almost all the critically ill patients received drugs containing at least one excipient. Significant numbers of critically ill neonates received at least one of either known to be harmful or potentially harmful excipients. Critically ill neonates had significantly greater daily exposure of macrogol than children and adults; and benzyl alcohol (v/v) and propyl paraben compared to adults. Critically ill neonates and children had greater exposure to benzyl alcohol (w/v), methyl paraben, sodium metabisulfite than adults did. Benzyl alcohol exposure was likely to be several-fold high in critically ill patients. Exposures to benzyl alcohol and propylene glycol were possibly linked to increased risk of mortality particularly in neonates. CONCLUSION: Critically ill neonates and children are likely to receive a significantly greater quantity of harmful excipients than critically ill adults. Benzyl alcohol and propylene glycol exposure are likely to be associated with increased risk of mortality in critically ill.

Clinical Pharmacokinetics of Vancomycin in Critically Ill Children.

BACKGROUND AND OBJECTIVE: Critically ill children exhibit altered pharmacokinetic parameters of vancomycin, mainly due to altered renal excretion and volume of distribution (as a result of altered plasma protein concentrations). We assessed the pharmacokinetic parameters of vancomycin in this subpopulation. METHODS: Vancomycin trough concentrations in critically ill children were obtained following first dose and at steady state. Using a one-compartment model, clearance (CL), volume of distribution (Vd), elimination half-life (t1/2), and area under the time-concentration curve for 24 h (AUC0-24) were estimated. Subgroup analyses were carried out, with patients differentiated based on age, renal clearance, outcome, and renal dysfunction. Protein-free vancomycin concentrations were calculated using a previously reported formula. RESULTS: Twenty-two samples were evaluated for first-dose and 182 for steady-state pharmacokinetics, and similar pharmacokinetic parameter values were observed at first dose and at steady state. Only 36.4% and 47.3% of the samples attained the recommended AUC0-24 (mg·hr/L) of > 400 at first dose and at steady state, while 62.5% of the patients with renal dysfunction achieved this target. Nearly 40% of the patients had augmented renal clearance (ARC), which was associated with higher CL, shorter t1/2, and lower AUC values. Amongst the patients with ARC, none had AUC0-24 (mg·hr/L) > 400 at first dose, while 16% achieved this target at steady state. Volume of distribution was significantly higher in infants and a decreasing trend was observed in toddlers, children, and older children at steady state. Children with renal dysfunction had lower CL, prolonged t1/2, and higher AUC values than patients with normal renal clearance at first dose. A good correlation was observed between trough concentration and AUC0-24, as corroborated by the area under the receiver operating characteristic curve. The median fraction of protein-free vancomycin was around 77%. CONCLUSION: Vancomycin dosing strategies in younger children should be revisited, and increased doses should be considered for critically ill children with ARC in order to achieve therapeutic concentrations of AUC0-24.

Vancomycin Use in a Paediatric Intensive Care Unit of a Tertiary Care Hospital.

BACKGROUND: Vancomycin is one of the commonly used anti-microbial drugs in intensive care units (ICUs). Guidelines recommend maintaining therapeutic trough levels of vancomycin (10-20 mg/L). The success of achieving the recommended therapeutic concentration of vancomycin is influenced by several factors, and this is even more complex in children, particularly those admitted in the ICU. Hence, we carried out the present study in children admitted in the ICU who were administered vancomycin. METHODS: We carried out a chart review of children admitted in the paediatric ICU unit of a tertiary care hospital over a period of 3 years. Information on their demographic factors, diagnoses, duration of hospital stay, vancomycin treatment (dose, frequency and time of administration) and concomitant drugs, and vancomycin trough levels were retrieved. Descriptive statistics were used for representing the demographic factors, and multivariable logistic regression analyses were carried out to assess the determining factors. RESULTS: One-hundred and two children were identified, of whom 13 had renal dysfunction. Two-hundred and fifty-two vancomycin trough levels were available, of which only 25% were observed in the recommended range (10-20 mg/L) amongst patients without any renal dysfunction and 22% amongst patients with renal dysfunction. Vancomycin was administered intravenously at an average [standard deviation (SD)] dose (mg/dose) of 13 (3.9) mostly either thrice or four times daily. Even in patients receiving vancomycin as a definitive therapy, only 40.9% achieved the recommended trough levels. Lower trough levels were associated with an increased risk of mortality. Nearly 4% of the levels were above 20 mg/L (toxic range). Seven children were suspected to have acute kidney injury (AKI) during the course of therapy where the cumulative vancomycin dose and mortality rate was higher. Only one serum vancomycin level during augmented renal clearance was observed in the recommended range. All the patients received at least one concomitant drug that either had nephrotoxic potential or predominant renal elimination, and use of a greater number of such drugs was associated with an increased risk of AKI. CONCLUSION: The current vancomycin dosing strategy is ineffective in achieving therapeutic trough levels in children admitted to the ICU. Sub-therapeutic vancomycin trough levels significantly increase the risk of mortality.