Acute ARDS is characterized by progressive hypoxemia, decreased lung compliance, intrapulmonary shunting, and non-cardiogenic pulmonary edema in an appropriate clinical setting. This, however, is well beyond the scope of this discussion. Mortality rates for ARDS in children are at best uncertain. The best estimates are based on very few patients. An ongoing multicenter randomized clinical trial of ECMO in ARDS suggests that survival may be improved with that modality.
Resistance is normal or near normal as is anatomic dead space.
Those areas that remain are normally compliant and therefore are subject to overdistension when subjected to excessive inflating pressures. When discussing approaches to mechanical ventilation in any setting some basic assumptions must be accepted. The higher the pressures used the greater the injury. Repeated expansion of collapsed alveoli may be injurious to the lung independent of overdistension or oxygen concentration. Practical aspects I have purposely avoided the trap of designating somewhat arbitrary limits or cutoff points as I believe they tend to obscure the more important issues.