Efficiency and Efficacy of Two Techniques of Preoxygenation during Modified Rapid Sequence Intubation

Apneic mass movement of oxygen by applying continuous positive airway pressure (CPAP) is possible only when the airway is kept patent which helps to reduce the rate of desaturation.

The aim of this study was to check the efficiency of preoxygenation and apneic oxygenation by assessing the drop in partial pressure of arterial oxygen (PaO₂) during apnea with and without keeping an oropharyngeal airway to maintain the patency of airway.

This prospective observational study was conducted at a tertiary care center.

Sixty patients undergoing robotic and laparoscopic-assisted surgeries requiring modified rapid sequence intubation were recruited for the study. In Group A, CPAP was not applied during preoxygenation and oropharyngeal airway was not used, but oxygen was administered at 5 L/min during the apnea. In Group B, CPAP of 5 cmH₂O was maintained during preoxygenation and after induction an oropharyngeal airway was inserted. Patients in both the groups were induced and paralyzed following standardized anesthesia protocol.

Chi-square test, independent t-test, and ANCOVA were used as applicable.

Group B showed significantly higher mean PaO₂ levels after preoxygenation (525.3 ± 42.5 vs. 500.8 ± 51) and at 90 s of apnea (494.8 ± 42.6 vs. 368.6 ± 98.4) as compared to Group A. The fall in PaO₂ was significantly lower in Group B. The rise in partial pressure of arterial carbon dioxide was comparable in both groups.

Preoxygenation with CPAP of 5 cmH₂O followed by apneic oxygenation with CPAP keeping the airway patent with an oropharyngeal airway results in significantly higher PaO₂ after preoxygenation and slower reduction in PaO₂ during apnea.