Effects of fiberoptic bronchoscopy on intracranial pressure in patients with brain injury: A prospective clinical study

Background: Fiberoptic bronchoscopy (FB) plays an important role in making the diagnosis of nosocomial pneumonia and resolving lobar atelectasis in cr itically injured trauma patients. It has been shown to be a safe procedure with only occasional complications. However, in patients with head injuries , FB can lead to intracranial hypertension, Sustained increases in intracra nial pressure (ICP) leads to poor outcome in these patients. Because of thi s, a prospective study was done not only to assess the effect of FB on ICP and cerebral perfusion pressure (CPP) in patients with brain injuries, but also to identify a regimen of sedation and anesthesia that could prevent si gnificant increases in ICP during FB. Methods: Twenty-six FB were performed in 23 patients with ICP monitors or I CP monitors and ventriculostomy drains in place for Glasgow Coma Scale scor e < 8 or management of postcraniotomy trauma. FB was performed to aid in th e diagnosis of nosocomial pneumonia or to aid in resolving lobar atelectasi s. Before FB, all patients received a standard anesthetic regimen consistin g of vecuronium (10 mg), morphine sulfate (4 mg!, and midazolam (2.5 mg), P atients with diminished cranial compliance, defined as ICP > 10 mm Hg, also received a nebulizer treatment of 3 mL of 4% lidocaine before FB, All pati ents were preoxygenated,with F-IO2 = 1.0 for 10 minutes, Intracranial press ure, mean arterial pressure, and CPP were monitored continuously throughout the procedure. These same variables were also recorded at baseline and at 2-minute intervals during the procedure. The time to return to baseline ICP was also recorded. Results: The mean ICP at baseline (immediately before FB) was 12.6 mm Hg, A fter introduction of the bronchoscope, the ICP rapidly increased in 21 proc edures (81%) and the mean highest ICP was 38.0 mm Hg, There was also a conc omitant increase in mean arterial pressure such that there was no substanti al change in CPP, The mean lowest CPP was 73.1 mm Hg. The average time for return of ICP to baseline was 13.9 minutes. In the subgroup of patients wit h ICP > 10, attempting to blunt the tracheal stimulation by anesthetizing t he trachea with 4% nebulized lidocaine did not seem to he successful. The m ean highest ICP in this subgroup was 41.8 mm Hg. The CPP changed in a simil ar manner, as the mean lowest CPP was 74.0 mm Hg, The mean time to return t o baseline was 12.5 minutes. No patient had acute neurologic deterioration secondary to EB. Conclusions: Although FB is an important procedure in the pulmonary care of head injured patients, it produces substantial, but transient, increases i n ICP and should be used with caution in patients with diminished cranial c ompliance. Sedation, analgesia, paralysis, and topical tracheal anesthesia did not completely prevent the rise in ICP, Although no acute deterioration in condition occurred, secondary brain injury caused by localized cerebral ischemia is certainly possible, Because of the substantial increases in IC P, herniation may be precipitated in an occasional patient. Further study i s needed to identify a regimen that will confer protection.