No abstract

Positive end-exspiratory pressure (PEEP) and nitric oxide (NO) can influence lung VA/Q-matching and pulmonary vascular resistance, and application of PEEP can increase exhaled NO in animals. To obtain a better understanding of these mechanisms, we examined how different types of ventilation or changes in CO2 affect the formation of endogenous NO. Exhaled NO in pentobarbital-anaesthetized rabbits was monitored by chemiluminescence. The animals were enclosed in a chamber and subjected to various modes of positive as well as negative pressure ventilation which was adjusted to induce similar changes in functional residual capacity (FRC) with maintained ventilatory rate and tidal volume. In addition, stepwise increase in FiCO2 (1.0-10%) was studied. Negative extrathoracic end-exspiratory pressure during negative extrathoracic pressure ventilation produced an increase in NO production similar to that of positive end-exspiratory pressure during positive pressure ventilation, the increase consisting of an initial peak followed by a plateau. The faster the FRC was increased, the higher was the initial peak in NO. The greater the increase in FRC, the higher was the plateau NO concentration. Increased FiCO2 caused a dose-dependent reduction in exhaled NO. The observations of lung distension effects on exhaled NO suggest the possibility of stretch receptors or -receptive mechanisms coupled to NO formation within the lung. In addition, NO formation in the lung is influenced by CO2 in a reciprocal fashion.

Evidence indicates that activation of the parasympathetic nervous system (PNS) suppresses physiological responses associated with motion sickness. Research also shows paced breathing increases PNS activation; the current study examines the use of paced diaphragmatic breathing (DB) training to quell motion sickness symptoms. Healthy participants (N = 60) were pre-screened for motion sickness susceptibility. Participants were then randomly assigned to either a control condition, focusing on environmental awareness, or to an experimental condition implementing paced DB. Following this, participants were exposed to a virtual reality (VR) motion sickness experience, while heart rate variability, breathing rate (RPM), and motion sickness ratings were collected. Results demonstrated participants in the DB condition had higher PNS activation and reported fewer motion sickness symptoms during the VR experience than the participants in the control condition. Results suggest that the DB protocol can be used to significantly increase PNS tone and decrease the development of motion sickness symptoms.

The results of this study point to other potential contributors to the obesity epidemic. Clinicians should consider providing strategies to enhance family communication and behavioral management to families with children who are overweight or obese.Policy: Policymakers who aim to reduce the obesity epidemic should consider how other modifiable factors within the family unit are associated with child eating.Research: Future research should explore these relationships using a longitudinal design to assess causality. If shown with longitudinal research, future interventions should consider how to address behavior management and family communication strategies within a behavioral family lifestyle intervention for pediatric obesity.

Results indicate possible benefits of using slow DB techniques in a motion sickness inducing environment.