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Inhaled NO has no apparent bronchodilator effect in the majority of acutely ill infants with RSV bronchiolitis and does not appear to provide any additional benefit over the use of salbutamol. The clinical benefit of inhaled NO as a bronchodilator is questionable under these conditions.

AimsTo determine the population pharmacokinetics of theophylline during extracorporeal membrane oxygenation (ECMO) from routine monitoring data. Methods Retrospective data were collected from 75 term neonates and children (age range 2 days to 17 years) receiving continuous infusions of aminophylline (mean rate 9.2 ± 2.6 m g kg -1 min -1 ) during ECMO. A total of 160 plasma concentrations (range 1-8 per patient), sampled at time intervals ranging from 10 h to 432 h, were included. Population PK analysis and model building were carried out using WinNonMix Professional (Version 2.0.1). Cross-validation was used to evaluate the validity and predictive accuracy of the model. Results A one-compartment model with first order elimination combined with an additive error model was found to best describe the data. Of the covariables tested, bodyweight significantly influenced clearance and volume of distribution, whereas age was an important determinant of clearance, as adjudged by the differences in the -2 ¥ log likelihood ( P < 0.005) and the residual error value. The final model parameters were estimated as: clearance (l h -1 ) = 0.023 ¥ bodyweight (kg) + 0.000057 ¥ age (days) and volume of distribution (l) = 0.57 ¥ bodyweight (kg). The interindividual variability in clearance and volume of distribution was 38% and 40%, respectively. The residual error corresponded to a standard deviation of 3.6 mg l -1 . Cross-validation revealed a median (95% confidence interval) model bias of 9.4% (2.9, 16.5%) and precision of 29.5% (24.8, 36.0%). Conclusions The estimated clearance is significantly lower, and volume of distribution higher, than previously reported in non-ECMO patients of similar age. These differences are probably a result of the expanded circulating volume during ECMO and altered renal and hepatic physiology in this critically ill group. Large interindividual variability reflects the heterogeneous nature of patients treated on ECMO.

Panton-Valentine leukocidin expressing S. aureus pneumonia can cause severe, necrotizing pneumonia associated with acute respiratory distress syndrome, which can be particularly challenging to manage. Extracorporeal membrane oxygenation support permits low pressure lung ventilation, avoiding barotrauma to lungs made friable by Panton-Valentine leukocidin expressing S. aureus infection. Although this is a small number of patients, the results are encouraging.