Alterations of respiratory function in patients with severe head injuries

Abstract

Summary: Studies were made of the ventilation and arterial acid-base balance of twenty-three patients who had suffered severe head injuries. The most frequent findings were an increased minute volume, an increased production of carbon dioxide, an arterial hypoxaemia, hypocapnia and a raised arterial pH. There was no instance of respiratory acidosis, and only three patients showed normal ventilation and acid-base values. The increased minute volume was associated not only with an increased carbon dioxide production, but also with a reduced arterial carbon dioxide tension and, therefore, with an increased alveolar ventilation, which may be due to hypoxaemia or to central factors which were not investigated. The hypoxaemia was associated with increased alveolar-arterial differences in oxygen tension, and with large values for the "physiological deadspace"; these indicated irregular ventilation-perfusion relationships. Aspiration andatelectasis at the time of the head injury may initiate the hypoxaemia, the increase in ventilation, and the arterial respiratory alkalosis which have been recorded. © 1968 John Sherratt and Son Ltd.