Four vital capacity breaths can delay the onset of haemoglobin desaturation following nasopharyngeal oxygen insufflation

Introduction. Prolonged apnoea occurring during endotracheal intubation leads to a fall in oxygen saturation. Preoxygenation helps in delaying the onset of fall in saturation Aim The aim of the study was to determine whether insufflation of oxygen via a nasopharyngeal catheter would prolong the duration of apnoea (fall in SpO ₂ <95%) after preoxygenation with 4 vital capacity breaths. Methods and materials Patients were divided into two groups of 20 each. Group ‘case’ received additional insufflation with oxygen during the period of apnoea while Group ‘control’ did not. O ₂ saturation was monitored during the period of apnoea and the study was terminated with a fall in O ₂ saturation to 95%, following which patients were ventilated. Results Time to fall in SpO to 95% in group ‘case’ was 6 mins (360 seconds) compared to group ‘control’ which was 4.1 mins (246 seconds) ² with a P value <0.05. The rise in EtCO in Group case was 16.6 mm of Hg as compared to the 11.7 mm of Hg rise in the Group control during ² the apnoeic period which was attributed to longer period of apnoea. The average rise in the EtCO2 per minute during the period of apnoea was 2.8mm of Hg. Conclusion Thus we concluded that nasopharyngeal O ₂ insufflation during the period of apnoea, after preoxygenation with 4 VC breaths, does delay the onset of O ₂ desaturation during apnoea and can be used as an effective tool in difficult airway management.