Diagnosis, management and pathophysiology of central sleep apnea in children.

Central sleep apnea (CSA) is thought to occur in about 1-5% of healthy children. CSA occurs more commonly in children with underlying disease and the presence of CSA may influence the course of their disease. CSA can be classified based on the presence or absence of hypercapnia as well as the underlying condition it is associated with.

A potential role for inducible nitric oxide synthase in the cerebral response to acute hemodilution.

Purpose: Acute anemia increases the cerebral expression of hypoxic molecules including neuronal nitric oxide synthase (nNOS) and hypoxia inducible factor-1alpha (HIF-1alpha). This study assessed the effects of acute hemodilution on inducible NOS (iNOS) and systemic inflammatory cytokines.

Methods: Anesthetized rats (n = 5-7 per group) underwent 50% hemodilution with pentastarch, whole blood exchange or no fluid exchange.

Anemia and cerebral outcomes: many questions, fewer answers.

A number of clinical studies have associated acute anemia with cerebral injury in perioperative patients. Evidence of such injury has been observed near the currently accepted transfusion threshold (hemoglobin [Hb] concentration, 7-8 g/dL), and well above the threshold for cerebral tissue hypoxia (Hb 3-4 g/dL). However, hypoxic and nonhypoxic mechanisms of anemia-induced cerebral injury have not been clearly elucidated.

Severe hemodilutional anemia increases cerebral tissue injury following acute neurotrauma.

Anemia may worsen neurological outcomes following traumatic brain injury (TBI) by undefined mechanisms. We hypothesized that hemodilutional anemia accentuates hypoxic cerebral injury following TBI. Anesthetized rats underwent unilateral TBI or sham injury (n > or = 7).

Increased expression of HIF-1alpha, nNOS, and VEGF in the cerebral cortex of anemic rats.

This study tested the hypothesis that specific hypoxic molecules, including hypoxia-inducible factor-1alpha (HIF-1alpha), neuronal nitric oxide synthase (nNOS), and vascular endothelial growth factor (VEGF), are upregulated within the cerebral cortex of acutely anemic rats. Isoflurane-anesthetized rats underwent acute hemodilution by exchanging 50% of their blood volume with pentastarch. Following hemodilution, mean arterial pressure and arterial Pa(O(2)) values did not differ between control and anemic rats while the hemoglobin concentration decreased to 57 +/- 2 g/l.