The effects of oxygen and hyperinflation on arterial oxygen tension after endotracheal suctioning

The effects of hyperinflation and increasing the FIO2 to 1.0 on PaO2 after endotracheal suctioning were examined in 28 patients after cardiac surgery. The changes in PaO2 immediately after and at 5- and 10-minutes after suctioning were compared with control values. Hyperinflation at the patient's baseline FIO2 produced a mean decrease in PaO2 of 18 mm Hg immediately after suctioning in over 75% of the sample. Preoxygenation with an increase in the ventilator FIO2 to 1.0 produced a mean increase in PaO2 of 48 mm Hg in 75% of the sample. Delivering preoxygenation by hyperinflation provided greater protection for all patients with a mean increase in PaO2 of 100 mm Hg. No statistically significant differences existed between the 5- and 10-minute PaO2 value and the control PaO2 values for any of the procedures. Experimental hyperinflation was aborted in two patients who experienced significant hypotension in association with the hyperinflation. The hypotension was transient, with arterial blood pressure immediately returning to baseline values on termination of the experimental hyperinflation. In conclusion, 100% oxygen administered by hyperinflation for 1 minute before and after endotracheal suctioning protects patients after cardiac surgery from a fall in PaO2. Because hyperinflation can cause alterations in arterial blood pressure and heart rate, these vital signs should be visually monitored during the endotracheal suctioning procedure.