Intraventricular Hemorrhage

. Intraventricular hemor­rhage (IVH) is a common problem almost exclusive to pre­mature infants. It ranks second only to RDS as a major cause of death in the premature infant. In infants born after less than 35 weeks' gestation or weighing less than 1400 g, the incidence is 40% to 50%, with the most im­mature at the highest risk for IVH. The hemorrhage often occurs in a subependymal germinal matrix layer (Fig. 2-7). This is a periventricular structure located between the cau­date nucleus and the thalamus at the level of or slightly posterior to the foramen of Monro. The germinal matrix is

FIGURE 2-7 Intraventricular hemorrhage in a premature infant. (From Rubin E., Farber J.L. [1999]. Pathophysiology [3rd ed.] Philadel­phia: Lippincott-Raven)

an early developmental structure that contains a fragile vascular area that is poorly supported by connective tissue. By term, this structure is gone.

Risk factors for IVH include pneumothorax, hypoten­sion, acidosis, coagulopathy, respiratory distress syndrome, and volume expansion. The proposed mechanisms for IVH include a hypoxic-ischemic insult resulting in cerebral hy-perperfusion of the germinal matrix area that causes vessel rupture. Another proposed mechanism is disruption of vascular integrity in the germinal matrix caused by hypo­tension. Four grades of hemorrhage have been identi­fied.¹²,¹⁸ Most hemorrhages resolve, but the more severe hemorrhages may obstruct the flow of cerebrospinal fluid, causing a progressive hydrocephalus (Table 2-2).