Effect of endotracheal suctioning on cerebral oxygenation in traumatic brain-injured patients

Objective: In patients with severe head injuries, brain damage occurs not o nly from the primary trauma but also secondarily from a reduction in cerebr al oxygenation as a result of brain swelling, ischemia, and elevated intrac ranial pressure (ICP), However, routine interventions designed to maintain oxygenation, such as endotracheal suctioning (ETS), also may negatively aff ect the cerebrovascular status by increasing the ICP, The purpose of this s tudy was to determine whether ETS influences cerebral oxygenation in patien ts with traumatic brain injury. Design: Descriptive, prospective, with repeated assessments within each pat ient. Setting: Ten-bed trauma intensive care unit in a university Level I trauma center. Subjects: Nineteen patients who were 16 yrs or older, had acute head injury , a Glasgow Coma Scale score less than or equal to 8, external ventricular drain and arterial pressure devices in place, and were intubated and mechan ically ventilated. Interventions: ETS protocol consisting of administration of four ventilator -delivered breaths at 135% of the patients' actual tidal volume, 100% F-IO2 , before and after suctioning with a standardized catheter at a 16-L flow r ate. Measurements and Main Results: This study examined cerebrovascular response s as measured by the traditional measures of ICP and cerebral perfusion pre ssure, as well as middle cerebral artery velocity and jugular venous oxygen tension that occurred during ETS in head-injured adults. The results of th is study show that both ICP and cerebral perfusion pressure are increased d uring ETS, In the majority of patients (84%), the ICP returned to baseline values within 2 mins, Conclusions: The increase in jugular venous oxygen tension associated with increases in middle cerebral artery velocity and mean arterial pressure sug gests that cerebral oxygen delivery was maintained during ETS. Cerebral cha nges associated with ETS using the described protocol are consistent with t he preservation of cerebral oxygenation.