Variability in usual care mechanical ventilation for pediatric acute lung injury: the potential benefit of a lung protective computer protocol

Abstract

Purpose: Although pediatric intensivists claim to embrace lung protective ventilation for acute lung injury (ALI), ventilator management is variable. We describe ventilator changes clinicians made for children with hypoxemic respiratory failure, and evaluate the potential acceptability of a pediatric ventilation protocol.

Methods: This was a retrospective cohort study performed in a tertiary care pediatric intensive care unit (PICU). The study period was from January 2000 to July 2007. We included mechanically ventilated children with PaO(2)/FiO(2) (P/F) ratio less than 300. We assessed variability in ventilator management by evaluating actual changes to ventilator settings after an arterial blood gas (ABG). We evaluated the potential acceptability of a pediatric mechanical ventilation protocol we adapted from National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI) Acute Respiratory Distress Syndrome (ARDS) Network protocols by comparing actual practice changes in ventilator settings to changes that would have been recommended by the protocol.

Results: A total of 2,719 ABGs from 402 patients were associated with 6,017 ventilator settings. Clinicians infrequently decreased FiO(2), even when the PaO(2) was high (>68 mmHg). The protocol would have recommended more positive end expiratory pressure (PEEP) than was used in actual practice 42% of the time in the mid PaO(2) range (55-68 mmHg) and 67% of the time in the low PaO(2) range (<55 mmHg). Clinicians often made no change to either peak inspiratory pressure (PIP) or ventilator rate (VR) when the protocol would have recommended a change, even when the pH was greater than 7.45 with PIP at least 35 cmH(2)O.

Conclusions: There may be lost opportunities to minimize potentially injurious ventilator settings for children with ALI. A reproducible pediatric mechanical ventilation protocol could prompt clinicians to make ventilator changes that are consistent with lung protective ventilation.

Fig 1

Flow diagram detailing the number of patients and observations of ABG and ventilator settings for the entire cohort of children, as well as the two subgroups of children with bilateral pulmonary infiltrates on chest X-ray (ALI Cohort) and those without co-morbidities that may affect ventilator management (Non co-morbid Cohort).

Fig. 2

Fig 2 (a, b): PEEP/FiO₂ titration tables from clinical care for all patients (a, top) and for patients with bilateral pulmonary infiltrates (ALI Cohort, b, bottom). The y axis represents actual PEEP values as a function of actual FiO₂ used (x-axis). The superimposed green boxes represent the pediatric mechanical ventilation protocol target combinations of FiO₂/PEEP. For all patients, there is variability in FiO₂/PEEP combinations clinicians choose. In general, clinicians use less PEEP than the protocol would recommend, particularly when FiO₂ climbs above 0.7. For the ALI cohort (b, bottom), clinicians may be more likely to increase PEEP, although they still use less PEEP than the protocol would recommend, particularly when FiO₂ climbs above 0.8. Actual value (diamond), Median (Bar), IQR (Box), Protocol Target (Green Boxes).