Chronic phase ventilation strategy in established severe bronchopulmonary dysplasia: A critical evaluation of the evidence.

We review the chronic phase ventilation (CPV) strategy recommended in infants with the most severe bronchopulmonary dysplasia (msBPD, mechanically ventilated at 36-40 weeks post-menstrual age). The safety and efficacy of CPV was important to scrutinize because msBPD is increasingly common, and infants with msBPD are often transferred to the Pediatric Intensive Care Unit (PICU) where the CPV strategy started in neonatal intensive care is expected to continue as the standard of care. First, we describe the CPV strategy, and the supporting evidence given by expert proponents. Second, we subject the supporting evidence to critical scrutiny and explain flaws that weaken support. Third, we give evidence that the strategy is based upon unsound pathophysiology and hence may be harmful. Fourth, we put this all together by making unstated (and unsupported) premises in explaining the benefit of CPV explicit. We made four conclusions. First, the literature suggested that CPV is based upon circular referencing among chapters and narrative reviews written by the same respected experts, and therefore, upon literature inadequately subjected to critical scrutiny. Second, these reviews explained physiologic theory with little supportive evidence that had likely been misinterpreted, and referred to outcome studies that did not examine the effect of the CPV strategy. Third, when implicit assumptions are made explicit, there is evidence to show a lack of consensus about and potential harms of the CPV strategy, and inaccurate interpretations of msBPD physiology. Fourth, there was no rationale that withstands critical scrutiny to suppose ventilated children with msBPD might be an exception to using a standard of care ventilation strategy used in acute lung disease. If the CPV strategy is beneficial, we urgently need better data to that effect; otherwise, it is too early to widely adopt what may be a harmful strategy as standard of care.