Impact of sustained neuromuscular blockade on outcome of mechanically ventilated children.BACKGROUND:  Neuromuscular blocking agents (NMBA) are commonly administered to critically ill children in pediatric intensive care units (PICU) in the USA and Europe. Although NMBA are frequently used in PICU patients, their role in the PICU setting has not yet been clearly defined. The aim of this study was to describe the sustained administration of NMBA and its impact on outcome of PICU patients. METHODS:  A 3-year retrospective cohort study was conducted to compare mechanically-ventilated patients who received NMBA for at least 12 h with patients who did not (control group). RESULTS:  A total of 317 consecutive patients were ventilated over 3473 days. Patients were similar in age, weight and severity scores. Thirty-four children (10.7%) received NMBA. Compared with controls, the neuromuscular blockade (NMB) group had a longer duration of mechanical ventilation (13.7 vs 5.5 days, P= 0.000), longer PICU stay (20 vs 11 days, P= 0.000) and increased occurrence of ventilator-associated pneumonia (6.6 vs 4.1/1000 ventilator days, P= 0.010). The NMB use was not associated with higher mortality (8.8% vs 17.6%, P= 0.287) or longer hospital stay (30.5 vs 23 days, P= 0.117). CONCLUSION:  Although the use of NMBA was not associated with greater mortality, we found that sustained use of NMBA is associated with prolonged mechanical ventilation, longer PICU stay and higher incidence of ventilator-associated pneumonia when compared with controls. Larger studies are necessary to confirm these findings.