Perfusion CT to quantify the cerebral vasospasm following subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: After subarachnoid hemorrhage (SAH), vasospasm is frequent and increases the risk of stroke and poor clinical outcome. The purpose of this study was to identify the best perfusion parameters in perfusion-CT (PCT) able to predict vasospasm diagnosed by angiography after SAH. METHODS: Seventy-six patients with SAH were investigated by PCT and cerebral angiography. Using regions of interest (ROI) on parametric maps of mean transit time (MTT), time to peak (TTP), cerebral blood volume (CBV) and cerebral blood flow (CBF), PCT data were compared to an arteriographic score in two categories (severe vasospasm: ≥ 50% and non-severe vasospasm: <50%) for each artery. Best PCT predictors of the arteriographic score were tested using multiparametric logistic regression. RESULTS: Among the 76 patients, PCT data were reliable in 65 patients. Twenty-seven patients had a severe vasospasm. Logistic regression showed that MTT was the best predictor of the arteriographic score. Using MTT, odds ratios having a vasospasm were superior to 3.1 and the occurrence of a vasospasm was accurately predicted in 78.5 to 100%, depending on the artery considered. However, no absolute value of the MTT could be identified to predict the occurrence of vasospasm. In fact, abnormal values of MTT ranged from 123 to 221% (m=146%) of the control values. DISCUSSION AND CONCLUSIONS: PCT may accurately identify severe vasospasm and might be used as a convenient noninvasive imaging modality to monitor patients with SAH. When detected, severe vasospasm could be confirmed and managed using angiography and endovascular treatment, appropriately.

Equimolar doses of mannitol and hypertonic saline in the treatment of increased intracranial pressure.

OBJECTIVE: To compare the effects of equimolar doses of 20% mannitol solution and of 7.45% hypertonic saline solution (HSS) in the treatment of patients with sustained elevated intracranial pressure (ICP). DESIGN: Parallel, randomized, controlled trial. SETTING: Two intensive care units in a university hospital. PATIENTS: A total of 20 stable patients with a sustained ICP of >20 mm Hg secondary to traumatic brain injury (n = 17) or stroke (n = 3). INTERVENTIONS: A single equimolar infusion (255 mOsm dose) of either 231 mL of 20% mannitol (mannitol group; n = 10 patients) or 100 mL of 7.45% hypertonic saline (HSS group; n = 10 patients) during 20 mins of administration. MEASUREMENTS: ICP, arterial blood pressure, cerebral perfusion pressure, blood flow velocities of middle cerebral artery using continuous transcranial Doppler, brain tissue oxygen tension, serum sodium and osmolality, and urine output during a study period of 120 mins. MAIN RESULTS: The two treatments equally and durably reduced ICP during the experiment. At 60 mins after the start of the infusion, ICP was reduced by 45% +/- 19% of baseline values (mean +/- sd) in the mannitol group vs. 35% +/- 14% of baseline values in the HSS group. Cerebral perfusion pressure and diastolic and mean blood flow velocities were durably increased in the mannitol group, resulting in lower values of pulsatility index at the different times of the experiment (p < .01 vs. HSS). No major changes in brain tissue oxygen tension were found after each treatment. Mannitol caused a significantly greater increase in urine output (p < .05) than HSS, although there was no difference in the vascular filling requirement between the two treatments. HSS caused a significant elevation of serum sodium and chloride at 120 mins after the start of the infusion (p < .01). CONCLUSIONS: A single equimolar infusion of 20% mannitol is as effective as 7.45% HSS in decreasing ICP in patients with brain injury. Mannitol exerts additional effects on brain circulation through a possible improvement in blood rheology. Pretreatment factors, such as serum sodium, systemic hemodynamics, and brain hemodynamics, thus should be considered when choosing between mannitol and HSS for patients with increased ICP.

Transcranial Doppler to detect on admission patients at risk for neurological deterioration following mild and moderate brain trauma.

OBJECTIVE: To investigate the contribution of transcranial Doppler measurements obtained in the emergency room for detecting patients with secondary neurological deterioration after mild or moderate brain trauma. DESIGN AND SETTING: Prospective cohort study in the emergency room in a university teaching hospital. PATIENTS: Seventy-eight adult patients admitted to the emergency room after a traumatic brain injury (TBI), including 42 patients with Glasgow Coma Score 14-15 and 36 with 9-13. MEASUREMENTS AND RESULTS: All patients had transcranial Doppler measurements on both middle cerebral arteries and computed tomography on admission. Neurological outcome was assessed 7 days after trauma. Of the patients included 7 and 10 had secondary neurological deterioration after mild and moderate TBI, respectively. On admission these groups of patients had significantly more injuries on computed tomography using the Trauma Coma Data Bank classification and higher pulsatility index using transcranial Doppler than the patients having no subsequent neurological worsening. CONCLUSIONS: Increased pulsatility index after mild or moderate TBI is a reason for concern about the possibility of further neurological deterioration. Computed tomography and Doppler measurements could be combined to detect on admission patients at risk for secondary neurological deterioration in order to improve their initial disposition.

Do patients still require admission to an intensive care unit after elective craniotomy for brain surgery?

BACKGROUND: After elective craniotomy for brain surgery, patients are usually admitted to an intensive care unit (ICU). We sought to identify predictors of postoperative complications to define perioperative conditions that would safely allow ICU bypass. METHODS: This observational cohort study enrolled 358 patients admitted to neuro-ICU after elective intracranial procedures. Postoperative complications were defined as unexpected events occurring within 24 hours of surgery that required imaging or treatment for neurologic deterioration. RESULTS: Fifty-two patients were transferred postoperatively to neuro-ICU with sedation and mechanical ventilation. Of the remaining 306 patients subjected to an attempt to awake and extubate in the operating room, 26 (8%) developed 1 postoperative complication, primarily a new motor deficit, unexpected awakening delay, or subsequent deterioration in consciousness. Four intracerebral hematomas required surgical evacuation and each of these was detected within 2 hours after surgery. Predictors of postoperative complications included failure to extubate the trachea in operating room [odds ratio 61.8; 95% confidence interval (CI) 12.2-312.5], and, to a lesser extent, a duration of surgery of more than 4 hours (odds ratio 3.3; 95% CI 1.4-7.8), and lateral positioning of the patient during the procedure (odds ratio 2.8, 95% CI 1.2-6.4). CONCLUSIONS: Our results encourage prospectively testing the hypothesis that patients with immediate, successful tracheal extubation after elective craniotomy for brain surgery, with a surgical duration of less than 4 hours in a nonlateral position could be monitored safely in the postanesthesia care unit before being discharged to a neurosurgical ward.