Stabilizing immature breathing patterns of preterm infants using stochastic mechanosensory stimulation

Abstract

Breathing patterns in preterm infants consist of highly variable interbreath intervals (IBIs) that might originate from nonlinear properties of the respiratory oscillator and its input-output responses to peripheral and central signals. Here, we explore a property of nonlinear control, the potential for large improvement in the stability of breathing using low-level exogenous stochastic stimulation. Stimulation was administered to 10 preterm infants (postconceptional age: mean 33.3 wk, SD 1.7) using a mattress with embedded actuators that delivered small stochastic displacements (0.021 mm root mean square, 0.090 mm maximum, 30-60 Hz); this stimulus was subthreshold for causing arousal from sleep to wakefulness or other detectable changes in the behavioral state evaluated with polysomnography. We used a test-retest protocol with multiple 10-min intervals of stimulation, each paired with 10-min intervals of no stimulation. Stimulation induced an approximately 50% reduction (P = 0.003) in the variance of IBIs and an approximately 50% reduction (P = 0.002) in the incidence of IBIs > 5 s. The improved stability of eupneic breathing was associated with an approximately 65% reduction (P = 0.04) in the duration of O(2) desaturation. Our findings suggest that nonlinear properties of the immature respiratory control system can be harnessed using afferent stimuli to stabilize eupneic breathing, thereby potentially reducing the incidence of apnea and hypoxia.

Stochastic Resonance Effects on Apnea, Bradycardia, and Oxygenation: A Randomized Controlled Trial

“…SR stimulation ameliorated every aspect of clinically significant oxygen desaturation events, with a 20% to 35% decrease in the number, duration, and intensity of These results are similar to previous work that used the SR mattress. Like Bloch-Salisbury et al, 8 we observed a 50% reduction in apneic events, but their definition of an apneic event was a pause in breathing of .5 seconds and ours was defined as a pause of $10 seconds. Similarly, Bloch-Salisbury et al showed a 65% reduction in the duration of oxygen desaturation, although we observed a more modest 35% reduction in the duration and a 21% reduction in the intensity of each oxygen desaturation event.…”

“…It is postulated that SR promotes stability and robustness of eupneic respiratory rhythm, modifying unstable respiratory pacemaker rhythms into a more stable rhythm, [12][13][14] possibly via visceral or somatic mechanoreceptors. 8 Another explanation for the efficacy of SR on the respiratory system is a direct pulmonary enhancement of gas exchange through mechanical perturbations of the network architecture of lung tissue. 15 With an unclear mechanism of action, there could be unanticipated short-and long-term benefits or risks.…”

“…SR stimulation was delivered in the form of gentle, low-amplitude displacements at the surface of the mattress with a frequency bandwidth of 30 to 60 Hz and displacements of 10 to 20 microns. In 13 infants we used a signal generator (Balance Engineering, Lexington, MA) and mattress (TheraSound), which provided vibration of the entire bedding surface, described previously by Bloch-Salisbury et al 8 In the remaining 23 infants, we used the Wyss Institute-developed signal generator and mattress, which contains an isolation unit that significantly dampens vibration to the rostral third of the mattress. 9 Otherwise, the 2 mattresses provided identical stimulation.…”

“…7 Previous research suggests that stochastic vibro-tactile stimulation can stabilize breathing patterns in premature infants. 8 Using a specialized SR mattress that provides mechanosensory stimulation via gentle subarousal vibrations, BlochSalisbury et al 8 found that stimulation resulted in significant reduction in the variance of interbreath intervals, the incidence of apneic pauses, and the duration of hypoxia in 10 preterm infants.…”

Apnea of prematurity: pathogenesis and management strategies

“…Low-level exogenous stochastic stimulation in stabilizing breathing pattern of preterm infants was tested in a recent study. 99 Mechanosensory stimulation was achieved using actuators embedded within the infant's mattress. The stimulus intensities were subthreshold for causing behavioral arousal or for causing shifts in the power spectrum of EEG activities.…”