Is Continuous Positive Airway Pressure Use Safe Following Endoscopic Transnasal Surgery?

The safety and timing of restarting CPAP following endoscopic anterior skull-base surgery (ESS) is debated, especially since the pressures delivered to the recently operated sinonasal cavity is unknown. Hence, we conducted an experimental study to measure the pressures delivered and assess the safety of restarting CPAP following sinonasal surgery.

Methods ([Figure 1]:) This IRB-approved prospective pilot study was conducted in patients with OSA on CPAP who required ESS for sinonasal disease. Codman sensors were used to measure pressures delivered to the mid-nasal cavity and sphenoid sinus while on CPAP and on consuming thick and thin liquids and gently blowing their nose. Mean pressures and the difference in pressure as delivered by the CPAP and as recorded by the sensor is reported in cm of water.

Results: Seven patients consented for the study. Mean age was 49.8 years, with a mean BMI of 39.2 kg/m². The baseline pressure at the sphenoid and mid-nasal cavity was −2.82 and −3.72 cm of H₂O, respectively. The mean pressures recorded at the sphenoid sinus and mid-nasal cavity while sipping thick liquids through a straw were −3.39 and −5.07, respectively, while sipping water through a straw were −2.65 and −4.59, and while gently blowing through the nose were −0.51 and −1.27. The pressure recorded at the sphenoid sinus was less than 65% of that generated by CPAP in all except one patient ([Table 1]). The pressure recorded at the mid-nasal cavity was less than 30% of that generated by CPAP in all patients. None of the patients developed any complications following CPAP use.

Conclusion: Restarting CPAP following FESS was found to be safe in patients undergoing ESS. The mean pressure delivered to the postoperative sphenoid sinus while on CPAP was less than 65% of the delivered pressures in all but one patient. This finding is less than the pressures shown in previous cadaveric studies, which detected sphenoid sinus pressures of around 88% of the delivered pressure. This suggests that mucosal edema, nasal packing, mucous, and blood clots seen in the postoperative state may serve as barriers to limiting the amount of CPAP pressure that can access the sphenoid sinus.

Table 1 Pressures delivered on CPAP

SI	CPAP pressure reading	Nasal cavity pressure on CPAP	Pressure (%) delivered to nasal cavity	Sphenoid pressure on CPAP	Pressure (%) delivered to sphenoid (%)
1	5.5	0	0	3.48	63.27
2	6	0.67	11.7	5.43	90.5
3	4	0.53	13.25	1.91	47.75
4	10	1.50	15	4.33	43.3
5	10	2.78	27.8	5.66	56.6
6	12	2.41	20	1.36	11.3
7	10	2.41	24.1	5.13	51.3

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
05 February 2024