Direct comparison of the effects of nebulized nitroprusside versus inhaled nitric oxide on pulmonary and systemic hemodynamics during hypoxia-induced pulmonary hypertension in piglets.

Objective: To test the hypothesis that nebulized nitroprusside and inhaled nitric oxide would not differ in producing selective pulmonary vasodilation during hypoxia-induced pulmonary hypertension in piglets.

Setting: University laboratory.

Subjects: Five piglets.

Hemodynamic homeostasis during acute hypoxia in septic and nonseptic piglets: differential role of prostaglandins and nitric oxide.

We studied the hemodynamic responses of 29 anesthetized and mechanically ventilated piglets to acute hypoxia [reduction of Pao2 from 130 to 38 mm Hg induced by inhalation of 7% fraction of inspired oxygen (Fio2) for 7.5 min] before and during group B beta-hemolytic streptococci (GBS) sepsis. During hypoxia, nonseptic piglets maintained stable systemic blood pressure [105+/-9 (SD) to 97+/-14 mm Hg] and cardiac output (CO) (667+/-72 to 685+/-113 mL/min).

Effects of nebulized nitroprusside on pulmonary and systemic hemodynamics during pulmonary hypertension in piglets.

We tested the effects of nebulized nitroprusside (Neb-NP) on pulmonary and systemic hemodynamics during pulmonary hypertension induced by hypoxia or group B streptococci infusion in piglets. Twenty-three anesthetized and mechanically ventilated piglets received Neb-NP under four experimental conditions: 1) normoxia; 2) 15 and 60 min of pulmonary hypertension induced by hypoxia; 3) after pretreatment with dipyridamole; 4) pulmonary hypertension induced by infusion of group B streptococci. In addition, Neb-NP was contrasted to nebulization of tolazoline.

The relationship between physician behaviors and blood gas values in the first hours of life--implications for "standards" of medical care for infants with respiratory distress.

It is standard practice for physicians to use blood gas (BG) evaluations when evaluating neonates with respiratory distress. In this study we addressed two questions: (1) What is the distribution of BG values in a population of infants receiving BG evaluation in the first 4 hours of life; and (2) How does the behavior of physicians correlate with BG values in these infants? We discuss the implications of our findings for claims about "standards" of medical care for newborn infants with respiratory distress. We reviewed medical records for 226 infants with birthweight > 2000 grams who were not intubated at the time of first BG determination.

Group B streptococcal sepsis impairs cerebral vascular reactivity to acute hypercarbia in piglets.

We investigated whether group B streptococcal (STREP) infusion impairs the cerebral blood flow (CBF) response to acute hypercarbia in piglets, and whether STREP-induced prostanoids or hemodynamic alterations could account for this impairment. Piglets, 2-3 wk old, were anesthetized, paralyzed, and mechanically ventilated (50% O2; partial pressure of arterial CO2 (PaCO2) approximately 40 torr). CBF was assessed by internal carotid artery blood flow (ICBF).