The respiratory response to CO2 and O2 in patients with coma due to voluntary intoxication with barbiturates and carbamates.

We have investigated the respiratory response to CO2 and to O2 in comatose subjects self intoxicated with barbiturates and carbamates. The chemical drive of 12 such patients with coma was compared with that of comparable normal subjects. The ventilatory response to CO2 was depressed but the P0.1 response was of the same order of magnitude as in normals. O2 had little effect on the ventilatory parameters and occlusion pressure. There was no difference between the two groups of patients, indicating that the respiratory changes observed were more dependent on the intensity of the intoxication than on the nature of the drugs. In addition, mechanical factors seem mainly responsible for the depressed ventilatory response to CO2.