Materials and Methods

All 12 of the patients studied had chronic obstructive emphysema and chronic alveolar hypoventilation. They were divided into two groups: Group I (TABLE 1) consisted of 7 patients with uncompensated respiratory acidosis, as indicated by a pH of 7.35 or below and an arterial carbon dioxide tension of 50 mm. Hg or above; Group I1 (TABLE 2) consisted of 5 patients with compensated respiratory acidosis, that is, with a pH value of the arterial blood of 7.30 or above and a carbon dioxide tension of 45 mm. Hg or above. All subjects were studied at bedside after overnight fasting. They were without premedication. Since the clinical condition of the patients did not permit detailed ventilatory tests, only arterial blood studies were carried out. These studies consisted of the determination of oxygen tension using the Clark electrode as adapted by Severinghaus, ascertainment of pH measurements using a capillary glass electrode and a Metrohm pH compensator, and determination of the carbon dioxide tension using the Severinghaus Pco2 electrode with the Instrumentation Laboratories P,,, meter. Arterial blood samples were drawn during a control phase at 15 min. intervals; an intravenous infusion wits then started that contained THAM in 0.3 M concentration as well as 5 mM/l. KCI and 30 mM/1. NaCI. The infusion was adjusted to an approximate rate of 100 mM/hour. Arterial blood samples were drawn a1 intervals