Abstract
Problem
Introduction: Rhinitis is a potential side effect of nasal continuous positive airway pressure (nCPAP) when applied to patients with obstructive sleep apnea. In the clinical setting, air humidification is regularly applied to treat these symptoms, but its benefits are controversial and human confounding factors may make it difficult to draw definitive conclusions. Animal models could therefore be useful. Objectives: To study the effects of air humidification as a mechanism that may reduce nasal inflammation during the application of nCPAP with or without an oral leak.
Methods
The study was divided into two phases. Phase I: 36 anesthetized Sprague-Dawley rats (300–360g) were subjected to nCPAP = 10cmH2O (n=12), sham-CPAP (n=12) and nCPAP with 100% air humidification (n = 12) for 5 hours. Nasal scraping was carried out on all the rats and Wright staining was performed to detect neutrophils. Phase II: The same procedure was applied to 33 rats exposed to nCPAP (n=11), nCPAP with a controlled mouth airleak (n=11) and nCPAP-airleak with 100% air humidification (n=11).
Results
Percentage of neutrophils in nucleated cells in the nasal scrapings was significantly (p=0.017) higher after 5 hours of nCPAP (0.96±0.90%) than in the control group (0.27±0.2%). When humidification was applied, the percentage of neutrophils was similar to that observed in the CPAP group (0.95±0.9%; p=0.97). When leakage was added there were no significant differences in the neutrophil count compared to nCPAP (0.75±0.5%; p=0.70). The application of humidified air to the rat with mouth airleak did not change the neutrophil count (1.17±1.2%; p=0.60).
Conclusion
Air humidification applied to an acute animal model of nCPAP with and without an oral air leak does not seem to reduce nasal inflammation.
Significance
The study is an intent to clarify the objective effects of the addition of air humidification into a CPAP device, in order to reduce rhinitic symptoms.
Support
Supported by FIS PI050194, by CIBERRes, and in part by Ministerio de Ciencia y Tecnología (SAF2005-00110 and SAF2004-00684).
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