Pharmacokinetic/pharmacodynamic modelling approaches in paediatric infectious diseases and immunology.

Pharmacokinetic/pharmacodynamic (PKPD) modelling is used to describe and quantify dose-concentration-effect relationships. Within paediatric studies in infectious diseases and immunology these methods are often applied to developing guidance on appropriate dosing. In this paper, an introduction to the field of PKPD modelling is given, followed by a review of the PKPD studies that have been undertaken in paediatric infectious diseases and immunology. The main focus is on identifying the methodological approaches used to define the PKPD relationship in these studies. The major findings were that most studies of infectious diseases have developed a PK model and then used simulations to define a dose recommendation based on a pre-defined PD target, which may have been defined in adults or in vitro. For immunological studies much of the modelling has focused on either PK or PD, and since multiple drugs are usually used, delineating the relative contributions of each is challenging. The use of dynamical modelling of in vitro antibacterial studies, and paediatric HIV mechanistic PD models linked with the PK of all drugs, are emerging methods that should enhance PKPD-based recommendations in the future

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

An Evaluation of Vancomycin Area Under the Curve Estimation Methods for Children Treated for Acute Pulmonary Exacerbations of Cystic Fibrosis Due to Methicillin‐Resistant Staphylococcus aureus

The prevalence of pulmonary methicillin‐resistant Staphylococcus aureus infections in patients with cystic fibrosis (CF) has increased over the last 2 decades. Two concentrations—a postdistributive and a trough—are currently used to estimate the area under the curve (AUC) of vancomycin, an antibiotic routinely used to treat these infections, to achieve the target AUC/minimum inhibitory concentration of ≥400 mg·h/L in ensuring optimal dosing of this drug. This study evaluated precision and bias in estimating vancomycin AUCs obtained either from a population pharmacokinetic (PK) model by using a single trough concentration or from standard PK equation–based 2‐point monitoring approach. AUCs were either obtained from a single trough concentration–fitted model or derived from a model fitted by 2 concentration points. Children ≥2 years of age with CF received intravenous vancomycin at 2 centers from June 2012 to December 2014. A population PK model was developed in Pmetrics to quantify the between‐subject variability in vancomycin PK parameters, define the sources of PK variability, and leverage information from the population to improve individual AUC estimates. Twenty‐three children with CF received 27 courses of vancomycin. The median age was 12.3 (interquartile range [IQR] 8.5–16.6) years. From the individual vancomycin PK parameter estimates from the population PK model, median AUC was 622 (IQR 529–680) mg·h/L. Values were not significantly different from the AUC calculated using the standard PK equation‐based approach (median 616 [IQR 540–663] mg·h/L) (P = .89). A standard PK equation‐based approach using 2 concentrations and a population PK model‐based approach using a single trough concentration yielded unbiased and precise AUC estimates. Findings suggest that options exist to implement AUC‐based pediatric vancomycin dosing in patients with CF. The findings of this study reveal that several excellent options exist for centers to implement AUC‐based pediatric vancomycin dosing for patients with CF