[The behavior of intracranial pressure under spontaneous respiration or artificial respiration in hemorrhagic shock during volume substitution].

Haemorrhagic shock and cranial injury frequently present together in the polytraumatised patient. The effect of different forms of ventilation--spontaneous respiration, controlled normoventilation, and intubation followed by hyperventilation--on the raised intracranial pressure of young pigs given volume replacement subsequent to haemorrhagic shock, was therefore investigated. During volume substitution, the intracranial pressure (initially 30 mmHg) both of those animals breathing spontaneously and of those being ventilated rose significantly (44.6 and 49.2 mmHg respectively). In contrast, intubation and hyperventilation resulted in an initial fall in intracranial pressure to 18.6 mmHg, and a rise to just below initial values (27.4 mmHg) after volume replacement. A similar blood pressure rise was noted in all three groups but arterial PCO2 changes were analogous to those of intracranial pressure. In the presence of both haemorrhagic shock and cranial injury, volume replacement alone is not sufficient treatment, and can in some circumstances be dangerous. Early intubation and controlled hyperventilation course a fall in intracranial pressure secondary to decreasing the PCO2.