Effects of Preoxygenation with Tidal Volume Breathing Followed by Apneic Oxygenation with and without Continuous Positive Airway Pressure on Duration of Safe Apnea Time and Arterial Blood Gases.
Background
Application of continuous positive airway pressure (CPAP) helps to recruit collapsed areas of the lung, which improves the oxygen reserve.


Aim of the Study
To compare the time to desaturate to 90% during apnea following preoxygenation and apneic ventilation with tidal volume breathing for 3 min with and without the application of CPAP.


Settings and Design
This prospective randomized study was conducted in a tertiary care institution.


Subjects and Methods
Twenty adult surgical patients were allocated into two groups. Group C patients were preoxygenated with 100% oxygen with CPAP of 20 cm H2O for 3 min. Group P patients were preoxygenated for 3 min without CPAP. In Group C, apneic oxygenation was initiated following induction and neuromuscular blockade with CPAP of 20 cm H2O. In Group P, no CPAP was applied. The study was terminated when the patient desaturated to 90%.


Statistical Analysis Used
Chi-square test and Mann-Whitney test.


Results
Group C had a significantly longer apnea time as compared to Group P (816.00 ± 30.98 vs. 348.00 ± 122.64 s). Three patients in Group P desaturated to <90% by 3 min and the remaining soon after 6 min. No patient in Group C desaturated till 12 min of apnea. PaO2 was significantly higher in Group C at 3 and 6 min of apnea. At 3 and 6 min, Group P had significantly lower saturation as compared to Group C.


Conclusion
Preoxygenation with CPAP significantly delayed desaturation during apnea with significantly higher arterial partial pressure of oxygen as compared to preoxygenation without CPAP.
['Rajan|Sunil|S|', 'Joseph|Nandhini|N|', 'Tosh|Pulak|P|', 'Paul|Jerry|J|', 'Kumar|Lakshmi|L|']
tidal volume breathing oxygenation continuous positive airway pressure Apneic ventilation PaO2