Effect of sighs on breathing memory and dynamics in healthy infants

Abstract

Deep inspirations (sighs) play a significant role in altering lung mechanical and airway wall function; however, their role in respiratory control remains unclear. We examined whether sighs act via a resetting mechanism to improve control of the respiratory regulatory system. Effects of sighs on system variability, short- and long-range memory, and stability were assessed in 25 healthy full-term infants at 1 mo of age [mean 36 (range 28-57) days] during quiet sleep. Variability was examined using moving-window coefficient of variation, short-range memory using autocorrelation function, and long-range memory using detrended fluctuation analysis. Stability was examined by studying the behavior of the attractor with use of phase-space plots. Variability of tidal volume (VT) and minute ventilation (VE) increased during the initial 15 breaths after a sigh. Short-range memory of VT decreased during the 50 breaths preceding a sigh, becoming uncorrelated (random) during the 10-breath presigh window. Short-range memory increased after a sigh for the entire 50 breaths compared with the randomized data set and for 20 breaths compared with the presigh window. Similar, but shorter duration, changes were noted in VE. No change in long-range memory was seen after a sigh. Coefficient of variation and range of points located within a defined attractor segment increased after a sigh. Thus control of breathing in healthy infants shows long-range stability and improvement in short-range memory and variability after a sigh. These results add new evidence that the role of sighs is not purely mechanical.

State-Dependent Modulation of Breathing in Urethane-Anesthetized Rats

“…Sighs are an important reflexive behavior (Bartlett, 1971) that function to prevent alveolar atelectasis, increase pulmonary compliance, and functional residual capacity, all of which are hypothesized to maintain lung volume and minimize the metabolic cost of breathing (Bartlett, 1971;Marshall and Metcalfe, 1988;Orem and Trotter, 1993;Hoch et al, 1998). It is also hypothesized that sighs are important in resetting respiratory and cardiovascular variability (Bartlett, 1971;Kahn et al, 1988;Franco et al, 2003;Baldwin et al, 2004). Importantly, statedependent changes in sigh rate that occur in natural sleep (Hoch et al, 1998;McNamara et al, 2002;Fukumizu and Kohyama, 2004;Qureshi et al, 2009) were similar to those described here under urethane anesthesia.…”

Children at high altitude have less nocturnal periodic breathing than adults

“…Although sighs have been described during sleep in infants [36] and in adults [28], their physiological significance is not well understood. Some data in infants suggest a role of sighs in restoration of lung mechanics [37] and in resetting the neuro-respiratory control system [36] or as a trigger of arousals during sleep [38]. Sighs in prepubertal children have not been investigated in detail.…”

Quantifying signals with power-law correlations: A comparative study of detrended fluctuation analysis and detrended moving average techniques

“…There is growing evidence that output signals of many physical [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15], biological [16,17,18,19], physiological [20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35] and economic systems [36,37,38,39,40,41,42,43], where multiple component feedback interactions play a central role, exhibit complex self-similar fluctuations over a broad range of space and/or time scales. These fluctuating signals can be characterized by long-range power-law correlations.…”