Continuous hypertonic saline therapy and the occurrence of complications in neurocritically ill patients.

OBJECTIVE: To evaluate potential side effects of continuous hypertonic 3% saline (CHS) as maintenance fluid in patients with brain injury. METHODS: Retrospective chart analysis of prospectively collected data. PATIENTS: Patients admitted to the neurosurgical intensive care unit for >4 days with traumatic brain injury, stroke, or subarachnoid hemorrhage with a Glasgow Coma Scale <9 and elevated intracranial pressure (ICP) or at risk of developing elevated ICP were included. Based on physician preference, one group was treated with 3% CHS at a rate of 1.5 mL/kg/bw as maintenance fluid. The other group received 0.9% normal saline (NS). Two percent saline was used in the CHS group to wean patients off 3% CHS or when sodium was above 155. Data on serum sodium, blood urea nitrogen, creatinine, ICP, infection rate, length of stay, rates of deep vein thrombosis, and pulmonary emboli and dural thrombosis were collected prospectively. RESULTS: One hundred seven patients in the CHS group and 80 in the NS group met the inclusion criteria. The incidence of moderate hypernatremia (Na >155 mmol/L) and severe hypernatremia (Na >160 mmol/L) was significantly higher in the CHS therapy group than in the NS group. No significant relationship between CHS infusion and renal dysfunction was found. Moderate and severe hypernatremia was associated with a higher risk of elevated blood urea nitrogen and creatinine levels. Acute renal failure was not seen in these patients. A total of 53.3% in the CHS group and in 16.3% in the NS group (p < 0.0001) had raised ICP (>25 mm Hg), consistent with the physicians decision to use CHS in patients with elevated ICP. CONCLUSIONS: CHS therapy was not associated with an increased rate of infection, deep vein thrombosis, or renal failure. However, there was a significant risk of developing hypernatremia. We conclude that CHS administration in patients with severe injuries is safe as long as sodium levels are carefully monitored.

Reproducibility of postprocessing of quantitative CT perfusion maps.

OBJECTIVE: The purpose of this study was to assess interobserver and intraobserver variability in evaluation of the reproducibility of quantitative data obtained in semiautomated postprocessing of CT perfusion data sets by observers of different levels of skill and experience and in fully automated postprocessing. MATERIALS AND METHODS: Twenty CT perfusion data sets were postprocessed by a neuroradiologist using an automated postprocessing program and by five observers (neuroradiology attending, neurology attending, radiology resident, senior and junior CT technologists) who received a brief training session in use of software for semiautomated postprocessing. For assessment of intraobserver variability, each observer repeated postprocessing of 10 CT perfusion data sets. Standard regions of interest were placed on identical locations for each observer's cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) maps of three brain regions: an ischemia-infarct region, normal cortical gray matter, and white matter. RESULTS: The variability in mean quantitative values of CBF, CBV, and MTT was 2.5-9.5% among all observers. Greater variability (20.4%) was introduced with the automated program. High correlation was found among all possible pairings of observers (r = 0.87-0.99). Low correlation was observed between automated postprocessing and postprocessing by all observers. Intraobserver variability in quantitative CT perfusion data ranged from 0.29% to 10.8%. High intraobserver correlation (r = 0.91-0.99) was found for the observers. CONCLUSION: Quantitative CBF, CBV, and MTT data obtained from postprocessing of CT perfusion data sets are reproducible among observers with varying levels of skill and experience. Observer interaction with the software is an important component for correct identification of user-defined parameters. Establishing a uniform and standard postprocessing technique is essential for maintaining good reproducibility.

Posterior reversible encephalopathy syndrome on computed tomography perfusion in a patient on "Triple H" therapy.

INTRODUCTION: This article reports a case of posterior reversible encephalopathy syndrome on compyted tomography (CT) perfusion in a patient on "Triple H" (hypertension, hypervolemia, and hemodilution) therapy following aneurysmal rupture repair. CASE REPORT: "Triple H" therapy is used in the postoperative course for treatment of vasospasm to prevent stroke and hemorrhage by maintaining cerebral perfusion pressure. DISCUSSION: A potential complication includes vasogenic edema from dysfunction of cerebral blood vessel autoregulation. CT perfusion can detect alterations in cerebral blood flow and volume caused by these hemodynamic changes.

Advances in endovascular aneurysm treatment: are we making a difference?

Recent advancements in endovascular aneurysm repair, including bioactive and expansile coils and intracranial stents, hold promise for improved aneurysm occlusion rates. We report the immediate and midterm clinical and angiographic outcomes of a consecutive series of patients treated since the advent of these technologies. Clinical and radiological records of 134 patients with 142 aneurysms treated between 2001 and 2004 were retrospectively evaluated by an independent neurologist. Endovascular procedures were analyzed by an independent neuroradiologist blinded to all clinical information. Seventy-two ruptured and 60 un-ruptured saccular aneurysms, nine fusiform and one post-traumatic aneurysm were treated. Matrix coils were used in 53% of saccular aneurysms and HydroCoils in 13% of all aneurysms. Neuroform stents were deployed in 19% of aneurysms. Angiographic total or subtotal occlusion was achieved in 76% of cases and in 96% at last follow-up. Aneurysm recanalization was observed in 14% over a mean follow-up of 12 months, and 18% of aneurysms were retreated. Clinically relevant complications occurred in 6.0%, resulting in procedure-related morbidity of 0.6% and 0.6% mortality at 6 months. No aneurysm bled over a cumulative 1,347 months of observation. Newer embolization technologies can be exploited successfully even in more complex aneurysms with very low morbidity and mortality.

Safety and feasibility of using a central venous catheter for rapid contrast injection rates.

OBJECTIVE: Our aim was to determine the safety and feasibility of using a central venous catheter for rapid contrast injections during CT. MATERIALS AND METHODS: An in vitro experiment was performed using a 7-French Arrow-Howes multilumen central venous catheter. Each catheter port was tested by varying contrast agent flow rates delivered by a power injector. Contrast media specifications were kept similar to routine clinical practice. The in vivo experiment included 104 cases in which rapid contrast injections, 3.0-5.0 mL/sec, were delivered through a central venous catheter for dynamic CT examinations. Patient monitoring for early complications of contrast extravasation, cardiac arrhythmia, and allergic reactions was performed. Contrast injections were monitored for pressure limitation, automatic flow-rate adjustment, and catheter injury. Chart review was performed for delayed complications of mediastinal hematoma, infection, or catheter malfunction. RESULTS: During the in vitro experiment, all desired flow rates, 3.0-9.9 mL/sec, could be delivered through the central venous catheter with no catheter injury. No immediate or early patient or catheter complications were observed during the in vivo experiment. Follow-up evaluation revealed that 18 blood cultures and one catheter culture were positive for bacterial growth. In a subgroup of 43 patients, five contrast injections were pressure-limited by the power injector, and only one had the flow rate automatically adjusted to 3.6 mL/sec from 4.0 mL/sec. CONCLUSION: Rapid contrast injection rates, at 3.0-5.0 mL/sec, through the Arrow-Howes multilumen central venous catheter are feasible and safe in the clinical setting. However, a strict protocol should be followed to avoid possible serious complications.

Critical care of neurotrauma.

Traumatic brain injury often affects people in their most productive years, inflicting a significant burden on families and society. The advances in modern critical care have improved survival of patients; thus more patients live after traumatic brain injury, which raises an important issue about their neurologic outcome. At the present time, there are limited data regarding methods to optimize neurologic recovery. In this review, we try to bring information from different sources to show new approaches to achieve that goal. Some of the techniques employed are investigational and some are waiting to find broader application in intensive care units across the country.