Adjustment of the Human Respiratory System to Increased Upper Airway Resistance During Sleep

Abstract

A cardiorespiratory model incorporating control of the human upper airway during sleep is described. Most previous models have not considered the possibility that the upper airway could be a limiting factor for gas exchange. Our model was developed to also predict certain pathophysiological phenomena in the cardiorespiratory system that characterize heavy snoring or sleep apnea. We started by adapting our collapsible upper airway model to include the impact of nasal passage and larynx, and extended the model with equations for gas exchange in the lungs. A feedback loop both to the respiratory pump and the upper airway dilator muscles was included. The model enabled successful breath-by-breath simulations of obstructive events of the upper airway. Although the model incorporates several physiologically relevant components of the system, the simulation results suggest that only few parameters suffice to predict the key adjustments that the cardiorespiratory system is known to make in patients with heavy snoring.

Computational fluid dynamics modeling of the upper airway of children with obstructive sleep apnea syndrome in steady flow

“…The interaction between area restriction and collapse has been explored as a possible mechanism for artery collapse, fatigue, and plaque rupture in arterial stenoses (Bathe and Kamm, 1999;Ku et al, 1990;Tang et al, 2001). In contrast, area restriction in the pharynx is often not considered to contribute to airway collapse, and the pharynx is modeled as a collapsible conduit downstream of a nasal resistance, with little native resistance to flow unless it collapses (Aittokallio et al, 2002;Isono et al, 1993). This simplification is probably reasonable in adults where the airway is much larger, but in children our analysis shows that with OSAS the pharyngeal resistance can be much larger than nasal resistance, based on the common MRI finding of anatomical restriction in the region of adeno-tonsillar overlap .…”

Overnight variability in transcutaneous carbon dioxide predicts vascular impairment in women

“…The predictor variables (referred to as features) included a number of numerical attributes extracted from the detected patterns in the , and signals (details on the signal processing and feature extraction are provided in the Supplementary Methods, and the full list of features are detailed in Supplementary Table 1). Inspired by our series of mathematical modelling studies (Aittokallio et al 2002, 2006 b , 2007), a special emphasis was placed on the features that reflect the overnight variability of the signal rather than its mean or quantile levels only. In particular, we characterized the dynamic behaviour of the signal at the onset of each recording (Initial slope), as well as transient changes that occurred during the recording period (called Pit patterns; see Fig.…”

Numerical Study of Blood Partial Pressure of the Human Respiratory System

“…[4][5][6] The work related to the ear pressure, patients' reciving pressure, support ventilation, and arterial pressure fluctuations has already been discussed. Michiaki Yamakage et al [7,8] provided the idea of the modeling of human respiratory system and discussed to airways in body system . [9,10] A lot of work has been done for ventilator dynamic and respiratory control.…”