EFFECT OF INTRAVENTRICULAR HEMORRHAGE ON PULMONARY-FUNCTION IN NEWBORN PIGLETS

Intracranial hemorrhage in the premature infant is often associated wi th respiratory failure and need for mechanical ventilation. We therefo re addressed the question of possible interactions with and pulmonary consequences of intraventricular hemorrhage. Newborn piglets were stud ied during intraventricular hemorrhage simulated by intraventricular b lood infusion. Infusion volume amounted to 8% of estimated brain weigh t. Respiratory rate, minute ventilation, lung resistance and dynamic l ung compliance, as well as arterial blood gases, arterial and intraven tricular pressures were measured. The piglets were mechanically ventil ated with a low basal rate of 20 breaths per minute throughout the stu dy. All piglets experienced significant rise in intraventricular press ure and respiratory failure during the study. Respiratory failure was mainly a result of a reduction in respiratory frequency and minute ven tilation until apnea. However, a rise in lung resistance was also note d while lung compliance did not change. We conclude that increased nee d for mechanical ventilation during intracranial hemorrhage is primari lty a consequence of hypoventilation. The increase seen in lung resist ance could also suggest that intraventricular hemorrhage causes an ele ment of bronchiolar constriction. Furthermore, these effects are not o nly a result of the increase in intraventricular pressure, but specifi c effects of blood components within the central nervous system must b e considered.