| Abstract: | Studies were made of the ventilation and arterial acid-basebalance of twenty-three patients who had suffered severe headinjuries. The most frequent findings were an increased minutevolume, an increased production of carbon dioxide, an arterialhypoxaemia, hypocapnia and a raised arterial pH. There was noinstance of respiratory acidosis, and only three patients showednormal ventilation and acid-base values. The increased minutevolume was associated not only with an increased carbon dioxideproduction, but also with a reduced arterial carbon dioxidetension and, therefore, with an increased alveolar ventilation,which may be due to hypoxaemia or to central factors which werenot investigated. The hypoxaemia was associated with increasedalveolar-arterial differences in oxygen tension, and with largevalues for the "physiological deadspace"; these indicated irregularventilation-perfusion relationships. Aspiration and atelectasisat the time of the head injury may initiate the hypoxaemia,the increase in ventilation, and the arterial respiratory alkalosiswhich have been recorded. |
