Effect of positive end-expiratory pressure on ductal shunting and systemic blood flow in preterm infants with patent ductus arteriosus.

Background: Left to right (L-R) shunting through a patent ductus arteriosus (PDA) can reduce systemic and cerebral blood flow in preterm infants. To minimize this, the positive end-expiratory pressure (PEEP) is often raised to increase pulmonary vascular resistance and reduce L-R shunting. The effects of this maneuver on systemic and cerebral hemodynamics and oxygenation are not well documented.

Effects of single-ventricle physiology with aortopulmonary shunt on regional myocardial blood flow in a piglet model.

Objectives: In single-ventricle physiology with aortopulmonary connection, diastolic hypotension could alter regional myocardial blood flow. Also, afterload increases could impair myocardial blood flow by increased wall tension and relative subendocardial malperfusion. This study explores the effects of acute single-ventricle physiology on regional myocardial blood flow distribution and investigates the consequences of moderate afterload augmentation on myocardial blood flow.

Near-infrared spectroscopy to monitor cerebral oxygen saturation in single-ventricle physiology.

Objectives: Near-infrared spectroscopy monitors cerebral oxygen saturation. This parameter parallels jugular venous oxygen saturation and reflects the balance between cerebral oxygen supply and demand. Experience with near-infrared spectroscopy in univentricular physiology is limited.

Distribution of cardiac output and oxygen delivery in an acute animal model of single-ventricle physiology.

Background: When single-ventricle physiology is established acutely (ie, after a Norwood procedure), the combination of limited cardiac output and hypoxemia could result in limited oxygen transport to systemic organs. This study investigates the regional distribution of cardiac output and oxygen delivery after creation of single-ventricle physiology.

Methods: Single-ventricle physiology was created in 8 piglets, and 8 other piglets served as sham control animals.

Single-ventricle physiology reduces cerebral oxygen delivery in a piglet model.

Background: In single-ventricle physiology, cerebral blood flow and oxygen (O2) delivery may be inadequate. This study tests the hypotheses that in acute univentricular physiology (1) cerebral blood flow increases inadequately to maintain O2 delivery, (2) the brain is incapable of increasing O2 extraction due to hypoxemia, and (3) cerebral O2 delivery diminishes selectively in different brain regions.

Material And Methods: Univentricular physiology was created in 8 piglets, while 8 animals were sham controls.