A Cadaveric Model for Measuring Continuous Positive Airway Pressure (CPAP) in the Nasal Cavity and Paranasal Sinuses: A Proof of Concept Study

Introduction: Obstructive sleep apnea (OSA) is a common respiratory disorder that can have negative effects on health and quality of life. There are numerous treatment options with positive pressure therapy (CPAP) being the primary modality. For patients undergoing endoscopic sinus or skull base surgery, there is a lack of consensus on the risk and appropriate postoperative use of CPAP. We present a novel proof-of-concept cadaver model for measuring sinonasal pressure delivered by CPAP.

Methods: Three fresh cadaver heads were prepared by removing the calvaria and brain. Sphenoidotomies were made and sellar bone was removed. Pressure sensors were endoscopically placed in the mid-nasal cavity, sphenoid sinus, and sella. CPAP was then applied and the pressure delivered to these anatomic points was recorded at progressively increasing levels of positive pressure. Paired t-test was used to analyze differences between pressure readings. Intraclass correlation coefficient was used to analyze the reliability of measurements.

Results: Increases in positive pressure led to increased pressure recordings for all locations. Nasal cavity pressure was on average 82% of delivered CPAP. Pressure was highest in the sphenoid sinus (90% of delivered CPAP with lateralized middle turbinates, 87% with medialized middle turbinates). The effect of middle turbinate medialization on intra-sphenoid pressure was not statistically significant. Intra-sellar pressure was 80% of delivered CPAP with lateralized turbinates and 84% with medialized turbinates. Pressure recordings demonstrated excellent reliability for all locations. All heads developed non–sellar-based cranial base leaks at higher pressures. Leaks from the cribriform region were successfully sealed with DuraSeal.

Conclusion: Our proof-of-concept cadaver model represents a novel approach to specifically measure pressures delivered to the nasal cavity and anterior skull base by CPAP. With further study, it may have broader clinical application to guide the safe postoperative use of CPAP in this population.