Influence of Sleep State and Respiratory Pattern on Cyclical Fluctuations of Cerebral Blood Flow Velocity in Healthy Preterm Infants

Abstract

To examine the influence of sleep state, respiratory pattern, and ventilation on cyclical fluctuations (CF) in cerebral blood flow (CBF) velocity (CBFV), we studied 21 ‘healthy’ preterm infants: birth weight 1,790 ± 162 g (SEM), study weight 1,960 ± 165 g, gestational age 32 ± 1 weeks, postnatal age 20 ± 4 (range 8–57) days. The CBFV was measured using on-line pulsed Doppler ultrasound by insonating the middle cerebral artery. Breathing was measured using a flow through system. The sleep state was monitored according to conventional criteria. Three hundred and seventy-five epochs of 1 min each were analyzed; 207 during quiet sleep (QS) and 168 during rapid eye movement (REM) sleep. CFs in CBFV were detected in all babies. The frequency of CF ranged from 0.5 to 6 cycles/min. The proportion of epochs showing CF was similar during both sleep states (56% QS vs. 59% REM; p = NS). Although the mean CBFV (cm/s) was similar in these two sleep states, the mean coefficient of variation, a measure of CF amplitude, was significantly higher during REM as compared with QS (6 ± 0.5 vs. 4.3 ± 0.2%; p < 0.05). Similarly, the mean CBFVs were similar with various respiratory patterns, but the coefficient of variation was significantly higher in periodic and apneic patterns as compared with regular and irregular respiratory patterns (5.6 ± 0.6% periodic, 5.6 ± 0.3% apneic, 3.6 ± 0.3% regular, and 4.1 ± 0.5% irregular; p < 0.05). The amplitude of CF was associated with the variability of the heart rate (p < 0.05), but not with the variability of the respiratory measurements. These findings suggest: (1) REM sleep is associated with a greater CBF variability than QS, and (2) periodic and apneic breathing are associated with a greater CBF variability than regular or irregular breathing. We speculate that sleep state and respiratory pattern do not determine but modulate the CBF. Our data suggest that in studies involving interpretation of CBFV data using the Doppler technique, breathing patterns should be taken into account in addition to sleep state.

Arterial blood flow and autonomic function in full‐term infants

“…The position-related change in blood-flow velocity found in the present investigation has been previously reported (Rehan et al, 1996;Eichler et al, 2001). The lack of a significant relationship between HRV, both short-and long-term, and blood-flow velocity in arteries supplying to the brainstem is in contrast to our hypothesis.…”

“…The position‐related change in blood‐flow velocity found in the present investigation has been previously reported (Rehan et al. , 1996; Eichler et al.…”

Neonatal color Doppler US study: Normal values of cerebral blood flow velocities in preterm infants in the first month of life

“…During the examinations nesting infants were in a supine position and their head was in a horizontal position (Anthony et al 1993;Baezinger et al 1995;Ichihashi et al 2002;Pellicer et al 2002) and in Prechtl state 3 (Ferrari et al 1994;Greisen et al 1985;Jorch et al 1990;Mukhtar et al 1982;Ramaekers et al 1989;Rehan et al 1996). Environmental light intensity was low and constant.…”

Assessment of cardio-respiratory interactions in preterm infants by bivariate autoregressive modeling and surrogate data analysis

“…The time delay and dynamics in this feedback system is modified by fluctuations in systemic and cerebral circulations, which are influenced by HRV. Correlated fluctuations in heart rate, arterial pressure cerebral circulation have been recorded in infants [21][22], and have been related to variability in breathing patterns of preterm infants [23]. Therefore information flow from HRV to respiration could be important in some infants making the interactions between HRV and respiration bi-directional and closed loop.…”