Using Graduated in Vivo Exposure to Treat a Claustrophobic Response to Nasal Continuous Positive Airway Pressure

Continuous positive airway pressure, aimed at preventing pulmonary atelectasis, has been used for decades to reduce lung injury in critically ill patients. In neonatal practice, it is increasingly used worldwide as a primary form of respiratory support due to its low cost and because it reduces the need for endotracheal intubation and conventional mechanical ventilation. We studied the anesthetized in vivo rat and determined the optimal circuit design for delivery of continuous positive airway pressure. We investigated the effects of continuous positive airway pressure following lipopolysaccharide administration in the anesthetized rat. Whereas neither continuous positive airway pressure nor lipopolysaccharide alone caused lung injury, continuous positive airway pressure applied following intravenous lipopolysaccharide resulted in increased microvascular permeability, elevated cytokine protein and mRNA production, and impaired static compliance. A dose-response relationship was demonstrated whereby higher levels of continuous positive airway pressure (up to 6 cmH2O) caused greater lung injury. Lung injury was attenuated by pretreatment with dexamethasone. These data demonstrate that despite optimal circuit design, continuous positive airway pressure causes significant lung injury (proportional to the airway pressure) in the setting of circulating lipopolysaccharide. Although we would currently avoid direct extrapolation of these findings to clinical practice, we believe that in the context of increasing clinical use, these data are grounds for concern and warrant further investigation.

Download Full-text

Nasal airway responses to nasal continuous positive airway pressure breathing: An in-vivo pilot study

Journal of Biomechanics ◽

10.1016/j.jbiomech.2016.04.034 ◽

2016 ◽

Vol 49 (9) ◽

pp. 1887-1890 ◽

Cited By ~ 4

Author(s):

David E. White ◽

Jim Bartley ◽

Muhammad Shakeel ◽

Roy J. Nates ◽

Robin K.S. Hankin

Keyword(s):

Pilot Study ◽

Continuous Positive Airway Pressure ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Nasal Airway ◽

Airway Responses

Download Full-text

Chronic continuous positive airway pressure (CPAP) reduces airway reactivity in vivo in an allergen-induced rabbit model of asthma

Journal of Applied Physiology ◽

10.1152/japplphysiol.01345.2010 ◽

2011 ◽

Vol 111 (2) ◽

pp. 353-357 ◽

Cited By ~ 29

Author(s):

Z. Xue ◽

Y. Yu ◽

H. Gao ◽

S. J. Gunst ◽

R. S. Tepper

Keyword(s):

Continuous Positive Airway Pressure ◽

Airway Inflammation ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Mechanical Strain ◽

Rabbit Model ◽

Therapeutic Benefit ◽

Airway Responsiveness ◽

Airway Reactivity

Previous studies have demonstrated that chronic mechanical strain produced by continuous positive airway pressure (CPAP) reduces in vivo airway reactivity in rabbits and ferrets. For CPAP to potentially have a therapeutic benefit for asthmatic subjects, the reduction in airway responsiveness would need to persist for 12–24 h after its discontinuation, require application for only part of the day, and be effective in the presence of atopic airway inflammation. In the present study, airway responsiveness to acetylcholine or methacholine was measured during mechanical ventilation following three different protocols in which active, nonanesthetized, tracheotomized rabbits were treated with High vs. Low CPAP (6 vs. 0 cmH2O). 1) High CPAP was applied continuously for 4 days followed by 1 day of Low CPAP; 2) High CPAP was applied at night and Low CPAP during the daytime for 4 days, and 3) High CPAP was applied for 4 days in animals following ovalbumin (Ova) sensitization and challenge. For all three protocols, treatment with High CPAP resulted in significantly reduced airway responsiveness compared with treatment with Low CPAP. Cumulatively, our in vivo results in rabbits suggest that high CPAP, even when applied only at night, produces a persistent reduction of airway responsiveness. In addition, CPAP reduces airway responsiveness even in the presence of atopic airway inflammation.

Download Full-text

Respiratory system responsiveness in rabbits in vivo is reduced by prolonged continuous positive airway pressure

Journal of Applied Physiology ◽

10.1152/japplphysiol.00165.2005 ◽

2005 ◽

Vol 99 (2) ◽

pp. 677-682 ◽

Cited By ~ 11

Author(s):

Z. Xue ◽

L. Zhang ◽

R. Ramchandani ◽

Y. Liu ◽

V. B. Antony ◽

...

Keyword(s):

Continuous Positive Airway Pressure ◽

Respiratory System ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Mechanical Strain ◽

Airway Reactivity ◽

Airway Function ◽

System Responsiveness

Active, nonanesthetized, tracheotomized rabbits were subjected to continuous positive airway pressure (CPAP) for 4 days to determine the effects of chronic mechanical strain on lung and airway function. Rabbits were maintained for 4 days at a CPAP of 6 cmH2O (high CPAP), at a CPAP of 0 cmH2O (low CPAP), or without tracheostomy (no CPAP). After treatment with CPAP, changes in respiratory resistance in response to increasing concentrations of inhaled ACh were measured during mechanical ventilation to evaluate respiratory system responsiveness in vivo. Intraparenchymal bronchial segments were isolated from the lungs of all animals to evaluate airway smooth muscle responsiveness and bronchial compliance in vitro. Rabbits maintained for 4 days at high CPAP demonstrated significantly lower responsiveness to ACh compared with rabbits that were maintained at low CPAP or with no CPAP. Airways isolated from the lungs of animals subjected to the chronic application of high CPAP were also less responsive to ACh in vitro than the airways isolated from animals subjected to low CPAP or no CPAP. The persistence of the decreased responsiveness in the excised airway tissues suggests that the decreased respiratory system responsiveness observed in vivo results primarily from direct effects on the airways. The results demonstrate that the application of prolonged mechanical strain in vivo can reduce airway reactivity.

Download Full-text

Continuous Positive Airway Pressure (CPAP) Therapy for the Treatment of Hypernasality: A Single Case Study

Perspectives on Speech Science and Orofacial Disorders ◽

10.1044/ssod24.2.48 ◽

2014 ◽

Vol 24 (2) ◽

pp. 48-58 ◽

Cited By ~ 3

Author(s):

Lakshmi Kollara ◽

Graham Schenck ◽

Jamie Perry

Keyword(s):

Continuous Positive Airway Pressure ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Single Case ◽

Treatment Method ◽

Post Treatment ◽

Subjective Perception ◽

Cpap Therapy ◽

Long Term Follow Up

Studies have investigated the applications of Continuous Positive Airway Pressure (CPAP) therapy in the treatment of hypernasality due to velopharyngeal dysfunction (VPD; Cahill et al., 2004; Kuehn, 1991; Kuehn, Moon, & Folkins, 1993; Kuehn et al., 2002). The purpose of this study was to examine the effectiveness of CPAP therapy to reduce hypernasality in a female subject, post-traumatic brain injury (TBI) and pharyngeal flap, who presented with signs of VPD including persistent hypernasality. Improvements in mean velopharyngeal orifice size, subjective perception of hypernasality, and overall intelligibility were observed from the baseline to 8-week post-treatment assessment intervals. Additional long-term assessments completed at 2, 3, and 4 months post-treatment indicated decreases in immediate post-treatment improvements. Results from the present study suggest that CPAP is a safe, non-invasive, and relatively conservative treatment method for reduction of hypernasality in selected patients with TBI. More stringent long-term follow up may indicate the need for repeated CPAP treatment to maintain results.

Download Full-text