EFFECTS OF RESPIRATORY THERAPY ON INTRACRANIAL-PRESSURE

To determine whether respiratory therapy can be deleterious in patients with intracranial hypertension, we investigated the effects of passive and active respiratory therapy on intracranial pressure (ICP) and cerebral perfusion pressure in acute neurosurgical patients with normal (< 15 mm Hg) and increased (> 15 mm Hg) ICP. During passive respiratory therapy, moving the patients from a 30-degree head-up dorsal position to the lateral decubitus position increased ICP by 10 mm Hg (P < .001) in normal ICP patients (n = 26) and by 6 mm Hg (P < .001) in high ICP patients (n = 6). Cerebral perfusion pressure increased by 5 mm Hg (P < .05) in both cases. Clapping did not further change ICP or cerebral perfusion pressure. During active respiratory therapy, ICP decreased by 2 to 3 mm Hg (P < .05) in normal ICP patients (n = 11) and by 4 to 7 mm Hg (P < .01) in high ICP patients (n = 7). Cerebral perfusion pressure decreased by 1 to 5 mm Hg and remained unchanged in normal and high ICP patients, respectively. The ICP reduction was attributed mainly to the decrease in PaCO2 and the decrease in intrathoracic pressure during active hyperventilation. These results indicate that passive and active respiratory therapy can be performed safely in acute neurosurgical patients with normal or increased ICP, provided the therapy can be done in a position that does not deteriorate ICP. © 1991.