Oscillations in Cardiovascular Function During Acute Hypoxia in the Newborn Piglet Are Associated With Less Neurological Damage and Occur More Frequently in Females

Abstract

The function of the cardiovascular system during hypoxia is an important determinant of neurologic outcome. Oscillations in blood pressure, particularly type-3 waves with a duration of 10 to 160 s, have been shown to occur in the presence of hypoxia in the neonatal rat. The aim of this study was to determine the characteristics and occurrence of type-3 waves in the neonatal piglet and any relationship to neurologic damage after acute global hypoxia. Hypoxia/hypercarbia was induced in 32 anesthetized piglets by reducing the fraction of inspired oxygen to 0.1 and the ventilation rate from 30 to 10 breaths per minute for 45 min. The degree of neurologic damage was assessed using both physiologic (EEG amplitude and cerebral impedance at 6 h posthypoxia) and structural (microtubule associated protein-2 immunohistochemistry) markers. Type-3 waves in cardiovascular function occurred in 56% of animals. An oscillating pattern was significantly associated with less neurologic damage (p = 0.01) and a lower duration of hypotension during hypoxia (p = 0.02), and occurred more frequently in females (p = 0.024).

Low‐frequency oscillations of murine skin microcirculations and periodic changes of [Ca2+]i and [NO]i levels in murine endotheliocytes: An effect of provocative tests

“…It increased the contribution of NO‐independent and NO‐dependent oscillations and decreased the contribution of the myogenic oscillations. Normobaric hypoxia causes the appearance of low‐amplitude low‐frequency oscillations of the skin and cerebral microcirculation in newborn piglets (T. A. Harris et al, 2009). Our results on increasing contribution of NO‐independent and NO‐dependent oscillations to SBP oscillations spectra in mice principally agree with these data.…”

Cuffless Blood Pressure Estimation Using Cardiovascular Dynamics

“…Cardiovascular oscillation could give information about blood pressure. There have been studies showing that during periods of stress the cardiovascular system displays more oscillations (Harris et al, 2009) and we know that stress causes temporary blood pressure elevation (Kulkarni et al, 1998). The oscillation can also occur in the presence of hypoxia which can result in higher blood pressure (Harris et al, 2009).…”

“…In addition to relationship between cardiovascular oscillation and blood pressure, a study on piglets has shown that the intensity of cardiovascular fluctuations is gender dependent and large changes happen less frequently in males compared to females (Harris et al, 2009).…”