Raj K. Narayan

Survey of critical care management of comatose, head-injured patients in the United States

OBJECTIVEnThis survey was designed to study current practices in the monitoring and treatment of patients with severe head injury in the United States.nnnDATA SOURCESnThe collected data represent answers to telephone interviews of nurse managers, clinical specialists, and staff nurses specializing in neurotrauma care at 277 randomly selected hospitals from a total pool of 624 trauma centers. Overall, 261 (94%) centers participated in the survey. Of the participating centers, 219 (84%) were providers of care for severely head-injured patients. In order to assess reliability and account for differences among respondents, personnel from 40 (15%) centers were resurveyed 6 months later and a different nursing professional was interviewed, although the questions remained the same.nnnDATA EXTRACTIONnThe largest group of respondents came from level I centers (49%), followed by level II (32%) and level III (2%). Thirty-four percent of the surveyed hospitals had a designated neurologic/neurosurgical intensive care unit, and 24% of all units surveyed were under the direction of either a neurosurgeon or a neurologist. Twenty-eight percent of the centers routinely performed intracranial pressure monitoring, while 7% of the centers reported never using this technique. The use of ventriculostomy catheters for intracranial pressure monitoring was employed in 72% of the centers, but cerebrospinal fluid drainage was utilized by only 44% of the hospitals. The percentage of patients who had their intracranial pressure monitored was significantly higher in level I trauma centers and at hospitals that treated larger numbers of severely head-injured patients (15 to 30 patients per month, which represented 15% of the hospitals surveyed). Hyperventilation and osmotic diuretics were used in 83% of centers to reduce intracranial hypertension. The administration of barbiturates was reported in 33% of the units as a treatment for intracranial hypertension. Corticosteroids were used more than half of the time in 64% of trauma centers. Twenty-nine percent of the centers reported aiming for PaCO2 values of < 25 torr (< 3.3 kPa).nnnCONCLUSIONSnThe survey data indicate that there is a considerable variation in the management of patients with severe head injury in the United States. The establishment of guidelines for the management of head injury based on available scientific data and moderated by practical and financial considerations may lead to improvement in the standard of care.

A clinical trial of progesterone for severe traumatic brain injury

BACKGROUNDnProgesterone has been associated with robust positive effects in animal models of traumatic brain injury (TBI) and with clinical benefits in two phase 2 randomized, controlled trials. We investigated the efficacy and safety of progesterone in a large, prospective, phase 3 randomized clinical trial.nnnMETHODSnWe conducted a multinational placebo-controlled trial, in which 1195 patients, 16 to 70 years of age, with severe TBI (Glasgow Coma Scale score, ≤8 [on a scale of 3 to 15, with lower scores indicating a reduced level of consciousness] and at least one reactive pupil) were randomly assigned to receive progesterone or placebo. Dosing began within 8 hours after injury and continued for 120 hours. The primary efficacy end point was the Glasgow Outcome Scale score at 6 months after the injury.nnnRESULTSnProportional-odds analysis with covariate adjustment showed no treatment effect of progesterone as compared with placebo (odds ratio, 0.96; confidence interval, 0.77 to 1.18). The proportion of patients with a favorable outcome on the Glasgow Outcome Scale (good recovery or moderate disability) was 50.4% with progesterone, as compared with 50.5% with placebo. Mortality was similar in the two groups. No relevant safety differences were noted between progesterone and placebo.nnnCONCLUSIONSnPrimary and secondary efficacy analyses showed no clinical benefit of progesterone in patients with severe TBI. These data stand in contrast to the robust preclinical data and results of early single-center trials that provided the impetus to initiate phase 3 trials. (Funded by BHR Pharma; SYNAPSE ClinicalTrials.gov number, NCT01143064.).

A novel dehydroepiandrosterone analog improves functional recovery in a rat traumatic brain injury model.

The purpose of this study was to investigate the efficacy of a novel steroid, fluasterone (DHEF, a dehydroepiandrosterone (DHEA) analog), at improving functional recovery in a rat model of traumatic brain injury (TBI). The lateral cortical impact model was utilized in two studies of efficacy and therapeutic window. DHEF was given (25 mg/kg, intraperitoneally) at the initial time point and once a day for 2 more days. Study A included four groups: sham injury, vehicle treated (n = 22); injured, vehicle treated (n = 30); injured, pretreated (5-10 min prior to injury, n = 24); and injured, posttreated (initial dose 30 min postinjury, n = 15). Study B (therapeutic window) included five groups: sham injury, vehicle treated (n = 17); injured, vehicle treated (n = 26); and three posttreatment groups: initial dose at 30 min (n = 18), 2 h (n = 23), or 12 h (n = 16) postinjury. Three criteria were used to grade functional recovery. In study A, DHEF improved beam walk performance both with pretreatment (79%) and 30-min posttreatment group (54%; p < 0.01, Dunnett vs. injured vehicle). In study B, the 12-h posttreatment group showed a 97% improvement in beam walk performance (p < 0.01, Dunnett). The 30-min and 12-h posttreatment groups showed a decreased incidence of falls from the beam, which reached statistical significance (p < 0.05, Dunnett). Tests of memory (Morris water maze) and neurological reflexes both revealed significant improvements in all DHEF treatment groups. In cultured rat mesangial cells, DHEF (and DHEA) potently inhibited interleukin-1beta-induced cyclooxygenase-2 (COX2) mRNA and prostaglandin (PGE2) production. In contrast, DHEF treatment did not alter injury-induced COX2 mRNA levels in the cortex or hippocampus. However, DHEF (and DHEA) relaxed ex vivo bovine middle cerebral artery preparations by about 30%, with an IC(50) approximately 40 microM. This was a direct effect on the vascular smooth muscle, independent of the endothelial cell layer. Fluasterone (DHEF) treatments improved functional recovery in a rat TBI model. Possible mechanisms of action for this novel DHEA analog are discussed. These findings suggest an exciting potential use for this agent in the clinical treatment of traumatic brain injury.

Clinical Evaluation of a Portable Near-Infrared Device for Detection of Traumatic Intracranial Hematomas

The purpose of this multicenter observational clinical study was to evaluate the performance of a near-infrared (NIR)-based, non-invasive, portable device to screen for traumatic intracranial hematomas. Five trauma centers collected data using the portable NIR device at the time a computed tomography (CT) scan was performed to evaluate a suspected traumatic brain injury (TBI). The CT scans were read by an independent neuroradiologist who was blinded to the NIR measurements. Of 431 patients enrolled, 365 patients were included in the per-protocol population analyzed. Of the 365 patients, 96 were determined by CT scan to have intracranial hemorrhages of various sizes, depths, and anatomical locations. The NIR device demonstrated sensitivity of 88% (95% confidence interval [CI] 74.9,95.0%), and specificity of 90.7% (95% CI 86.4,93.7%), in detecting the 50 intracranial hematomas that were large enough to be clinically important (larger than 3.5u2009mL in volume), and that were less than 2.5u2009cm from the surface of the brain. For all 96 cases with intracranial hemorrhage, regardless of size and type of hemorrhage, the sensitivity was 68.7% (CI 58.3,77.6%), and specificity was 90.7% (CI 86.4,93.7%). These results confirm the results of previous studies that indicate that a NIR-based portable device can reliably screen for intracranial hematomas that are superficial and of a size likely to be of clinical importance. The NIR device cannot replace CT scanning in the diagnosis of TBI, but the device might be useful to supplement clinical information used to triage TBI patients, and in situations in which CT scanning is not readily available.

Hypothermia for Traumatic Brain Injury — A Good Idea Proved Ineffective

Traumatic brain injury is an important cause of death and disability in both civilians and military personnel.1 In areas with organized trauma care systems and adequate critical care, the mortality...

Brain temperature measurement: A study of in vitro accuracy and stability of smart catheter temperature sensors

The injured brain is vulnerable to increases in temperature after severe head injury. Therefore, accurate and reliable measurement of brain temperature is important to optimize patient outcome. In this work, we have fabricated, optimized and characterized temperature sensors for use with a micromachined smart catheter for multimodal intracranial monitoring. Developed temperature sensors have resistance of 100.79u2009±u20091.19Ω and sensitivity of 67.95xa0mV/°C in the operating range from15–50°C, and time constant of 180xa0ms. Under the optimized excitation current of 500xa0μA, adequate signal-to-noise ratio was achieved without causing self-heating, and changes in immersion depth did not introduce clinically significant errors of measurements (<0.01°C). We evaluated the accuracy and long-term drift (5xa0days) of twenty temperature sensors in comparison to two types of commercial temperature probes (USB Reference Thermometer, NIST-traceable bulk probe with 0.05°C accuracy; and IT-21, type T type clinical microprobe with guaranteed 0.1°C accuracy) under controlled laboratory conditions. These in vitro experimental data showed that the temperature measurement performance of our sensors was accurate and reliable over the course of 5xa0days. The smart catheter temperature sensors provided accuracy and long-term stability comparable to those of commercial tissue-implantable microprobes, and therefore provide a means for temperature measurement in a microfabricated, multimodal cerebral monitoring device.

Smart catheter flow sensor for real-time continuous regional cerebral blood flow monitoring

We present a smart catheter flow sensor for real-time, continuous, and quantitative measurement of regional cerebral blood flow using in situ temperature and thermal conductivity compensation. The flow sensor operates in a constant-temperature mode and employs a periodic heating and cooling technique. This approach ensures zero drift and provides highly reliable data with microelectromechanical system-based thin film sensors. The developed flow sensor has a sensitivity of 0.973u2009mV/ml/100u2009g/min in the range from 0 to 160u2009ml/100u2009g/min with a linear correlation coefficient of R2u2009=u20090.9953. It achieves a resolution of 0.25u2009ml/100u2009g/min and an accuracy better than 5u2009ml/100u2009g/min.

Low-Dose rt-PA Enhances Clot Resolution in Brain Hemorrhage: The Intraventricular Hemorrhage Thrombolysis Trial

Background and Purpose— Patients with intracerebral hemorrhage and intraventricular hemorrhage have a reported mortality of 50% to 80%. We evaluated a clot lytic treatment strategy for these patients in terms of mortality, ventricular infection, and bleeding safety events, and for its effect on the rate of intraventricular clot lysis. Methods— Forty-eight patients were enrolled at 14 centers and randomized to treatment with 3 mg recombinant tissue-type plasminogen activator (rtPA) or placebo. Demographic characteristics, severity factors, safety outcomes (mortality, infection, bleeding), and clot resolution rates were compared in the 2 groups. Results— Severity factors, including admission Glasgow Coma Scale, intracerebral hemorrhage volume, intraventricular hemorrhage volume, and blood pressure were evenly distributed, as were adverse events, except for an increased frequency of respiratory system events in the placebo-treated group. Neither intracranial pressure nor cerebral perfusion pressure differed substantially between treatment groups on presentation, with external ventricular device closure, or during the active treatment phase. Frequency of death and ventriculitis was substantially lower than expected and bleeding events remained below the prespecified threshold for mortality (18% rtPA; 23% placebo), ventriculitis (8% rtPA; 9% placebo), symptomatic bleeding (23% rtPA; 5% placebo, which approached statistical significance; P=0.1). The median duration of dosing was 7.5 days for rtPA and 12 days for placebo. There was a significant beneficial effect of rtPA on rate of clot resolution. Conclusions— Low-dose rtPA for the treatment of intracerebral hemorrhage with intraventricular hemorrhage has an acceptable safety profile compared to placebo and historical controls. Data from a well-designed phase III clinical trial, such as CLEAR III, will be needed to fully evaluate this treatment. Clinical Trial Registration— Participant enrollment began before July 1, 2005.

Delay in Arrival to Care in Perpetrator-Identified Nonaccidental Head Trauma: Observations and Outcomes.

BACKGROUNDnChildren who sustained nonaccidental head trauma (NAHT) are at severe risk for mortality within the first 24 hours after presentation.nnnOBJECTIVEnExtent of delay in seeking medical attention may be related to patient outcome.nnnMETHODSnA 10-year, single-institution, retrospective review of 48 cases treated at a large tertiary Childrens Hospital reported to the New York State Central Registrar by the child protection team was conducted. The perpetrator was identified in 28 cases on the basis of confession or conviction. The medical and legal records allowed for identification of time of injury and the interval between injury and arrival to the hospital; this information was categorized as follows: <6 hours (without delay); 6-12 hours (moderate delay); and >12 hours (severe delay). The Kings Outcome Scale for Childhood Head Injury (KOSCHI) score was recorded for each case.nnnRESULTSnAll children were 3 years of age or younger (2.1-34 months) and predominantly male (68%; 19/28). On arrival, 61% of patients (17/28) presented with moderate or severe delay. A low arrival Glasgow Coma Scale (GCS) score (P < 0.0001) and extracranial injuries (P < 0.0061) correlated with worse clinical patient outcomes. Patients with an arrival GCS score <7 predominantly arrived without delay or with moderate delay. Patients presenting without delay or with severe delay were more likely to have a higher KOSCHI outcome score on discharge (P < 0.0426). Four of the 6 patients who died presented after moderate delay.nnnCONCLUSIONnPatients presenting to medical care 6-12 hours after NAHT (moderate delay) appeared to have worse outcomes than those presenting earlier or later.

Cerebral blood flow sensor with in situ temperature and thermal conductivity compensation

A micromachined blood flow sensor with in situ tissue temperature and thermal conductivity compensation was developed for the continuous and quantitative measurement of intraparenchymal regional cerebral blood flow. The flow sensor operates in a constant-temperature mode and employs a periodic heating and cooling technique. Thermal conductivity compensation is realized by sampling the peak current outputs at the beginning of the heating period and the baseline temperature variation during the heating period is compensated by an integrated temperature sensor. This approach provides highly reliable data with MEMS-based thin film sensors. It achieves sensitivity of 1.467 mV/ml/100gram-min in the linear range from 0 to 160 ml/100gram-min.