[Criteria of tolerance of the hypercapnia-hypoxia test]

Examination of 84 essentially healthy men, aged 19 to 34 years, by the rebreathing method showed that in various test subjects the reserve time prior to decompensation was in the range 5 to 9 min. A certain change was seen 1-2 min before termination of the test due to acute respiratory failure. This change included an increase in the minute respiration volume above 40 1/min and its relative increment by 10 1/min or over when compared to the preceding minute. The test time varied from 4 to 8 min. Analysis of the data using the cardiorespiratory index which is equal to the product of heart rate by systolic arterial pressure divided by the minute respiration volume helped to discriminate test subjects with satisfactory, good and very good tolerance of the rebreathing test.