[Studies on hypercapnia in patients with lung tuberculosis (author's transl)]

Pathophysiologic ecologic and therapeutic study was made on respiratory disturbances, especially on hypercapnia in patients with lung tuberculosis. 1) Of all in-patients (497 cases), 192 (38.6%) had respiratory disturbances, among which 70 cases (14.1%) exhibited hypercapnia. 2) Of these hypercapnic patients, about one-third (31.4%) were after thoracoplastic surgery, the main disturbances being restrictive in nature. In the half of non-operative cases, obstruction and inadequate gas mixing were the main cause for hypercapnia. 3) Critical values for inducing hypercapnia were % VC 45 for patients with restrictive disturbances and FEV1-0%/expected VC 40 for hypercapnic patients. 4) Significant band in the PaCO2 similar to (HCO-3) regression chart in patients (20 cases) with chronic stable hypercapnia showed a linear relationship with an increasing PaCO2, given by an equation, (HCO-3)p = 7.7 + 0.43 PaCO2 (PaCO2 45 -- 113 mmHg, SD = +/- 1.2, r = 0.99). Twelve percent of the unstable patients (100 cases) showed an alkalosis (pH greater than 7.45) over the range above 45 mmHg of PaCO2. 5) Even in patients with normal pH values, administered HCO-3 was estimated to move into the intracellular or interstitial fluid. 6) Increase in oxygen consumption was greater with increasing ventilation volume in hypercapneic patients. Even in these patients, voluntary or drug-induced hyperventilation caused a decrease in PaCO2, resulting in an amelioration of suppressed respiration under oxygen or even pethidine HCl administration. Discussion was made on the usefulness of these therapies on patients with hypercapnia.