Pathogenetic aspects of oxygen therapy in patients with respiratory insufficiency at PaО2 more than 55 mm HG

Abstract

The aim of this study was to elaborate indication criteria for oxygen therapy and its modes for the treatment of hypoxemia with РаО₂ above 55 mm Hg, on the basis of assessment of separate links of respiratory chain. We studied 18 consecutive patients (age of 41 to 80 years) with respiratory insufficiency (stage 2–3). Minute ventilation (MV), tidal volume (Vt), breathing frequency (BF), forced expiratory volume in one second (FEV₁), single-breath lung diffusing capacity (TLCOsb), arterial partial carbon dioxide tension (РаCО₂), arterial partial oxygen tension (РаО₂), arterial oxygen saturation (SaCb), arterial oxygen content (СО₂), anion gap (AG) were measured while breathing room air (baseline) and after 2 hours of oxygen therapy. Reactions of patients to oxygen-enriched air and to carbon dioxide-enriched air were compared.

Analisis of obtained data showed that respiratory assessment during tentative oxygen treatment is very important before indication of oxygen. Some patients during oxygen therapy produced alterations in breathing pattern with reduction of Vt and increase in BF (rapid, shallow breathing). Oxygen therapy may be of little benefit in the cases of redused diffusing capacity and high hemoglobin concentration.