Preoxygenation: Comparison of Maximal Breathing and Tidal Volume Breathing Techniques
Preoxygenation with tidal volume breathing for 3–5 min is recommended by Hamilton and Eastwood. This report compares tidal volume preoxygenation technique with deep breathing techniques for 30–60 s.Methods
The study was conducted in two parts on patients undergoing elective coronary bypass grafting. In the first group (n = 32), each patient underwent all of the following preoxygenation techniques: the traditional technique consisting of 3 min of tidal volume breathing at an oxygen flow of 5 l/min; four deep breaths within 30 s at oxygen flows of 5 l/min, 10 l/min, and 20 l/min; and eight deep breaths within 60 s at an oxygen flow of 10 l/min. The mean arterial oxygen tensions after each technique were measured and compared. In the second group (n = 24), patients underwent one of the following techniques of preoxygenation: the traditional technique (n = 8), four deep breaths (n = 8), and eight deep breaths (n = 8). Apnea was then induced, and the mean times of hemoglobin desaturation from 100 to 99, 98, 97, 96, and 95% were determined.Results
In the first group of patients, the mean arterial oxygen tension following the tidal breathing technique was 392 ± 72 mmHg. This was significantly higher (P< 0.05) than the values obtained following the four deep breath technique at oxygen flows of 5 l/min (256 ± 73 mmHg), 10 l/min (286 ± 69 mmHg), and 20 l/min (316 ± 67 mmHg). In contrast, the technique of eight deep breaths resulted in a mean arterial oxygen tension of 369 ± 69 mmHg, which was not significantly different from the value achieved by the traditional technique. In the second group of patients, apnea following different techniques of preoxygenation was associated with a slower hemoglobin desaturation in the eight-deep-breaths technique as compared with both the traditional and the four-deep-breaths techniques.Conclusion
Rapid preoxygenation with the eight deep breaths within 60 s can be used as an alternative to the traditional 3-min technique.