Conventional mechanical ventilation: traditional and new strategies.

Important breakthroughs in neonatology, particularly in prevention and treatment of respiratory disorders, have extended the limits of viability to lower gestational ages. Despite these advances, conventional mechanical ventilation (CMV) (usually pressure-limited intermittent mandatory ventilation in neonates) remains an essential therapy in neonatal intensive care. Advances in CMV, exogenous surfactant supplementation, and antenatal steroids have resulted in improved outcomes of critically ill neonates. Despite newer alternative ventilatory modes, such as high-frequency ventilation and patient-initiated mechanical ventilation, CMV continues to be the mainstay in the care of neonates. Improved survival due to advances in neonatal care has resulted in an increased number of infants who are at risk for chronic lung disease and air leaks. Although the etiology of lung injury is multifactorial, recent animal and clinical data indicate that lung injury is largely dependent on the ventilatory strategies used. Optimal ventilatory strategies may improve the benefitto-risk ratio by providing the best gas exchange with the smallest amount of lung injury. This article highlights the concepts of pulmonary mechanics, gas exchange, control of breathing, and lung injury that can be used to optimize CMV. Alternative modes of ventilation also are addressed. This evidenced-based review uses data from integrative studies (eg, meta-analyses, randomized clinical trials) whenever possible. However, because many controversies surrounding CMV have not been resolved with clinical studies, lesser levels of evidence are used as appropriate.