Cardiopulmonary interaction

OBJECTIVE: To highlight and review the physiology and pathophysiology of cardiopulmonary interaction in the critically ill pediatric patient. DATA SOURCE: A MEDLINE-based literature source. OUTLINE OF REVIEW: This review is divided into two sections: 1) The physiologic basis of cardiopulmonary interaction, and 2) critical clinical conditions in which cardiac and/or pulmonary dysfunction impact each other in the provision of adequate oxygen delivery. The physiology section focuses on the original research identifying fundamental volume-pressure and pressure-flow relationships and then proceeds to discuss how changes in intrathoracic pressure and lung volume affect ventricular loading conditions. The clinical section chooses several common scenarios in which this normal physiology is altered and an understanding of the impact of these physiologic aberrations on cardiac and/or pulmonary function is required to make sound management decisions. CONCLUSIONS: Improving oxygen transport balance is the primary goal in the management of children with life-threatening disorders. To optimize the opportunity for a successful outcome, the intensivist must understand the complex relationship between the cardiac and pulmonary systems in the effort to provide sufficient oxygen to meet the body's metabolic demands. Furthermore, the application of therapies separately designed to support the function of the heart and the function of the lungs may be synergistic or antagonistic, further complicating the management scheme. We conclude that this review will encourage the reader to pursue further literature or perhaps engage in further research related to this often underappreciated but vital interplay between cardiac and pulmonary functions.