Optimizing fresh gas flow and circuit design for the delivery of 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.

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Comparison of Work of Breathing on High Gas Flow and Demand Valve Continuous Positive Airway Pressure Systems

CHEST Journal ◽

10.1378/chest.82.6.692 ◽

1982 ◽

Vol 82 (6) ◽

pp. 692-695 ◽

Cited By ~ 105

Author(s):

R. T. Noel Gibney ◽

Roger S. Wilson ◽

Henning Pontoppidan

Keyword(s):

Continuous Positive Airway Pressure ◽

Airway Pressure ◽

Gas Flow ◽

Positive Airway Pressure ◽

Work Of Breathing

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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.

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