Biomedical subjects

C F Contant

Publications and source records attributed to C F Contant.

At least 37 records · Page 2Linked to original sources

PubMed1998

Hyperglycemia increases neurological damage and behavioral deficits from post-traumatic secondary ischemic insults.

The effects of post-traumatic administration of glucose 2.0 g/kg was compared to saline infusion with and without control of brain temperature at 37 degrees C on behavioral and histological measures of brain injury after controlled cortical impact injury complicated by a secondary ischemic insult. The glucose infusion increased blood glucose concentration from 114 +/- 4 to 341 +/- 76 mg/dl prior to the secondary ischemic insult. The resulting outcome measures were significantly worse in the glucose infusion group than in either control group. Mortality rate was significantly increased by the glucose administration, from 0% to 55% (p < 0.001). The median contusion volume was increased from 7.9 to 64.2 by glucose administration (p < 0.001) and the neuronal loss in the CA1 and CA3 areas of the hippocampus were greater in the glucose infusion group. In the animals that survived for the 2 weeks of behavioral studies, the duration of beam balance was shorter; the percent of animals that could balance on the beam for at least 60 s was less, the percent of animals that could perform the beam-walking task was less, and the length of time required to find the platform in the Morris water maze task was longer in the glucose infusion group. These studies demonstrate that the infusion of glucose after the cortical impact injury significantly increases the damage caused by post-traumatic ischemic insults. The adverse effect on neurological outcome could not be explained by the temperature effects of glucose infusion.

Animals↗

PubMed1998

Temporal effect of severe controlled cortical impact injury in the rat on the myogenic response of the middle cerebral artery.

The present study examined the effect of severe traumatic brain injury (TBI) on the myogenic response in the rat middle cerebral artery (MCA). Rats were subjected to severe controlled cortical impact (CCI; 5 m/sec, 130-msec duration, 3-mm deformation) injury over the right parietal cortex. At 2, 24, and 120 h postinjury, ipsilateral and contralateral segments of MCAs were isolated, mounted in a vessel chamber, and pressurized. After equilibration, the myogenic tone, the difference in vessel diameter in the presence and absence of calcium for a given pressure, and the myogenic response (the active contractile response elicited by a vessel to increasing pressure), were measured. At 24 h postsurgery, there was a significant interaction between myogenic tone and pressure in the ipsilateral and contralateral MCAs when TBI was compared to shams. However, this was not apparent, at the 2- and 120-h time points. At 2- and 24-h postsurgery, there was a significant interaction between myogenic response and pressure in the ipsilateral MCAs when TBI was compared to shams. While the response of the vascular smooth muscle was altered following injury, it was still functioning, suggesting that these vessels compensate, perhaps through alternate mechanisms or by relying on those remaining intact mechanisms.

Animals↗

PubMed1998

Hemophilia growth and development study: relationships between neuropsychological, neurological, and MRI findings at baseline.

OBJECTIVE: To determine the effects of human immunodeficiency virus (HIV) infection on children's development by identifying neurological and environmental variables associated with neuropsychological measures of cognitive development in HIV-seronegative (HIV-) and HIV-seropositive (HIV+)children and adolescents with hemophilia. METHODS: Participants (N = 298; 60% HIV+) were males ages 7-19 years enrolled in the Hemophilia Growth and Development Study (HGDS). Least squares modeling was used to determine whether there was a difference at baseline in mean neuropsychological test scores by HIV status, age, and neurological baseline findings, adjusting for selected environmental and medical history variables. RESULTS: The participants were within age expectations for general intelligence. Variables associated with lowered neuropsychological performance included academic problems, coordination and/or gait abnormalities, parents' education, and previous head trauma. CONCLUSIONS: Hemophilia-related morbidity has a subtle adverse influence on cognitive performance. HIV infection was not associated with neuropsychological dysfunction in this group even when MRI abnormalities were present.

Adolescent↗

PubMed1998

Relationship of brain tissue PO2 to outcome after severe head injury.

OBJECTIVE: To determine thresholds of brain tissue PO2 (PbtO2) that are critical for survival after severe head injury. DESIGN: Prospective data collection. SETTING: Neurosurgical intensive care unit of Ben Taub General Hospital, a comprehensive academic neurosurgical facility and Level I trauma center. PATIENTS: Forty-three severely head-injured patients who were not obeying commands on presentation or whose condition deteriorated to this level shortly after admission. INTERVENTIONS: Intracerebral placement of Licox (n=39) or Paratrend (n=4) PO2 probes during craniotomy or in the intensive care unit. MEASUREMENTS AND MAIN RESULTS: PbtO2 monitoring continued for an average of 84.6+/-41.8 hrs. The probes were calibrated before insertion according to the manufacturer's specifications. After removal, probes were tested in room air and in blood gas standard calibration solutions. PbtO2 data were analyzed by comparing the average time that PbtO2 was below the values of 20, 15, 10, 8, 6, 4, and 2 torr (2.7, 2.0, 1.3, 1.0, 0.8, 0.5, and 0.3 kPa, respectively) in patients who were living 3 mos after injury vs. those who died. A Tobit regression analysis using maximum likelihood methods was utilized. Both Licox and Paratrend probes functioned well in room air and in the Level I control. However, in the zero-oxygen solution, the Paratrend probes gave an average reading of 7.0+/-1.4 torr (0.9+/-0.2 kPa), compared with 0.3+/-0.3 torr (0.04+/-0.04 kPa) for the Licox probes. CONCLUSIONS: Analysis of the PbtO2 monitoring data suggested that the likelihood of death increased with increasing duration of time at or below a PbtO2 of 15 torr (2.0 kPa) or with the occurrence of any PbtO2 values of < or =6 torr (< or =0.8 kPa).

Adolescent↗

PubMed1998

Correlation of near infrared spectroscopy cerebral blood flow estimations and microsphere quantitations in newborn piglets.

We compared cerebral blood flow (CBF) estimated using transmission mode near infrared spectroscopy (NIRS) and a modification of the Fick principle with CBF quantitations by radioactive microspheres (MSs) in newborn piglets. Thirteen piglets were studied during steady state, ischemia, and during two reflow periods. NIRS and MS flows were not significantly different during any measurement period. NIRS flows were compared to total brain blood flows and to regional brain blood flows quantitated with MSs and correlated best with temporal cortical flows. Linear regression analysis of the NIRS flows plotted against MS-quantitated temporal cortical flows showed r = 0.71. Thus, CBFs obtained with NIRS were not significantly different from, showed the same directional changes, and correlated acceptably with flows quantitated by MSs.

Animals↗

PubMed1997

Effects of anesthesia on polyamine metabolism and water content in the rat brain.

Because variances have been noted in brain putrescine levels of anesthetized rats (control, SHAM-operated), we investigated the effects of several anesthetics on polyamine metabolism and water content in the adult rat brain. Short duration (5 min) anesthesia was studied in three groups: ketamine:xylazine [KX; 40 and 8 mg/kg, respectively, intraperitoneal injection (IP)], urethane (UR; 1.5 g/kg, IP), and isoflurane (IF, initially 3.5% in 100% O2, followed by a maintenance dose of 2.5% IF in 100% O2). Effects of IF at longer duration (30 min) were also studied because this paradigm is often used in our laboratory. Control rats received no anesthesia (NA). Following decapitation, tissue samples were obtained from 3 bilateral brain regions: parietal cortex, motor area (CPm); parietal cortex, somatosensory area (CPs); and the pyriform cortex (CPF). The polyamines, spermidine and spermine, and their precursor, putrescine, were quantified by HPLC-fluorometric detection and brain water content was determined by wet-to-dry weight measures. KX decreased putrescine (54%) and spermidine (20%) in the CPs, increased spermine (24%) in the CPF, and increased water content in all brain regions. UR decreased putrescine (51%) and slightly increased water content (0.7%) in the CPF. Short duration IF decreased putrescine and spermidine in all brain regions; decreased spermine in the CPm, and increased water content in the CPF (0.8%). In contrast, longer duration IF increased putrescine (181%) and spermidine (23%) in the CPm, with no change in water content. Anesthetics produce region-specific changes in putrescine, polyamines, and water content in the rat brain which could contribute to the experimental variability.

Anesthesia, General↗

PubMed1997

Positive end expiratory pressure reduces intracranial compliance in the rabbit.

Acute respiratory distress syndrome is commonly encountered in head-injured patients. Positive and expiratory pressure (PEEP) is useful in improving oxygenation. However, PEEP, by increasing intrathoracic pressure, decreases venous return, mean arterial pressure, and cardiac output and increases jugular vein pressure. There is conflicting evidence in the literature as to the potential effect of PEEP on intracranial pressure (ICP). The present study was undertaken to examine the effect of PEEP on ICP and intracranial compliance. Twelve male rabbits weighing 3.5-4.5 kg were used. The following parameters were monitored: arterial blood pressure, ICP (intraparenchymal Camino device), PaCO2, and PaO2. A space-occupying lesion was produced by inflation of a double lumen pediatric Swan-Ganz catheter placed over the right parietal dura. The amount of fluid required to reach the point of exponential increase of ICP was recorded at PEEP of 0 and 10 cm H2O. The mean volume needed to reach the deflection point of ICP was significantly lower when PEEP was 10 cm H2O compared to the value when PEEP was 0 cm H2O (685 +/- 48 vs. 883.3 +/- 46 microliters, respectively; p < 0.01). The results of the present study indicated that PEEP of 10 cm H2O decreases intracranial compensatory reserves for maintaining ICP at normal levels in the presence of an expanding intracranial mass.

Animals↗

PubMed1996

In vivo gene therapy of ovarian cancer by adenovirus-mediated thymidine kinase gene transduction and ganciclovir administration.

Efficacy and toxicity of adenovirus-mediated transfer of the herpes simplex virus thymidine kinase gene followed by administration of ganciclovir were studied in vivo. A human epithelial ovarian cancer animal model was established in nude mice using the serous ovarian adenocarcinoma cell line Ov-ca-2774. Intraperitoneal (ip) injection of 1 x 10(8) Ov-ca-2774 cells resulted in tumor growth and formation of malignant ascites in all 15 animals. In a prospective randomized experimental design mice were treated 1, 3, or 7 days after ip injection of 1 x 10(8) cells with ip injection of 2 x 10(8), 6.7 x 10(8), or 2 x 10(9) pfu ADV.RSV-TK followed by administration of ganciclovir (10 microgram /ml, ip, bid) for 6 consecutive days. End points were survival and toxicity. Mice treated with GCV or HSV-TK alone died from 14.4 +/- 1.7 to 19.5 +/- 3.5 days after treatment as did untreated controls. No toxicity of ADV.RSV-TK was found up to 2 x 10(9) pfu (2 x 10(11) particles). The mice with the highest tumor burden treated with the lowest viral dose lived significantly longer than controls (P < 0.05). Median survival in all other groups of mice treated with ADV.RSV-TK plus GCV was even longer (P < 0.01). Treatment benefit was dependent on ADV/RSV-TK dose and tumor burden. Adenovirus-mediated thymidine kinase gene therapy is a realistic approach to ovarian cancer treatment that warrants investigation in the clinical setting.

Adenoviridae↗

PubMed1996

Evaluation of a carbohydrate-free diet for patients with severe head injury.

Hyperglycemia, which may be caused or exacerbated by conventional diets, may worsen the neurological outcome from severe head injury, especially if secondary ischemic insults occur. The purpose of this study was to evaluate an experimental diet intended to replace systemic caloric and protein requirements without producing hyperglycemia. In initial studies in the laboratory, 5 experimental diets were employed in a middle cerebral artery temporary occlusion model. The effects of the diets on blood biochemistry and on infarction volume were compared in fasted animals and in animals fed a control diet. Animals fed the experimental diets had a significantly lower preischemia blood glucose concentration, a higher blood concentration of ketone bodies, and a smaller infarct volume than the animals fed a control diet. One diet chosen from the laboratory study was then evaluated in a clinical study as a randomized, open-label trial. Twenty severely head-injured patients were randomly assigned to be fed the experimental diet, EN-9305, or the control diet, Osmolyte HN, for the first 2 weeks after injury. Both treatment groups had similar blood glucose concentrations, averaging 6.33 +/- 0.21 mumol/mL (114 +/- 4 mg/dL), on day 1 prior to starting the assigned diet. Blood glucose concentration increased in the control diet group to a peak of 8.37 +/- 0.94 mumol/mL (151 +/- 17 mg/dL) on day 7 as the infusion rate of the diet was increased to the final rate. In the experimental diet group, the blood glucose concentration remained unchanged from fasting levels as the diet was advanced. Blood lactate concentration was lower, and blood ketone body concentrations were higher in the patients fed the experimental diet. Urinary nitrogen balance was better in the experimental diet group, but measures of visceral protein sparing, including serum albumin, plasma retinol binding protein, and total lymphocyte count, were not significantly different in the 2 treatment groups. Measures of cerebral anaerobic metabolism, including CSF lactate concentration and cerebral lactate production, were not significantly different in the 2 treatment groups. These studies suggest that a carbohydrate-free diet such as EN-9305 might have advantages for patients with severe head injury by replacing systemic caloric and protein requirements without producing hyperglycemia.

Adult↗

PubMed1995

Intracranial pressure waveform indices in transient and refractory intracranial hypertension.

Analysis of data obtained by continuous computerized monitoring of intracranial pressure (ICP) in 109 adult patients with severe head trauma was performed to examine the pattern of change in indices of the ICP waveform. Indices derived from direct measurement of the ICP wave and obtained from a Fast Fourier Transform (FFT) were examined. Concurrent physiologic measurements were made. Two types of intracranial hypertension (ICH) were defined for comparison. 'Transient intracranial hypertension' occurred when an abrupt rise in ICP was followed by a return to below 25 mm Hg (n = 63). Increases in ICP that were progressive and led to neurologic deterioration and death were termed 'refractory intracranial hypertension' (n = 18). During transient ICH heart rate, arterial pressure, end-tidal carbon dioxide and jugular venous oxygen saturation all increased, while these measures either were unchanged or decreased during refractory ICH. The pulse amplitude of the ICP wave increased in both types of ICHtn. Other changes in the waveform indices were consistent with this change in pulse amplitude. HFC responded differently to the two types of changes, with an increase during the transient changes and a decrease during the refractory changes. The differences in changes in physiologic measurements as ICH occurred in the 2 groups suggest that in refractory ICH cerebral blood flow is maintained against the mounting ICP, while in transient ICH the hypertension is caused by an increase in cerebral blood flow. The waveform indices do not discriminate between the two types of changes.

Adult↗

PubMed1995

SjvO2 monitoring in head-injured patients.

Jugular venous oxygen saturation (SjvO2) measures the balance between cerebral oxygen delivery and cerebral oxygen consumption. Abnormalities that increase oxygen consumption (e.g., fever or seizures) or that decrease oxygen delivery (e.g., increased ICP, hypotension, hypoxia, hypocapnia, or anemia) can decrease SjvO2. Measuring SjvO2 continuously in the ICU in 177 patients with severe head injury, jugular venous desaturation (SjvO2 < 50%) was identified at least once in 39% of the patients. Approximately half of the episodes of desaturation were due to intracranial hypertension and half were due to systemic causes. The occurrence of one or more episodes of desaturation was strongly associated with a poor outcome, suggesting that the reduction in oxygen delivery identified with the SjvO2 monitoring contributed to the neurological injury. In the operating room, jugular venous desaturation was identified in 6 of 8 patients who were monitored during emergency evacuation of a traumatic intracranial hematoma. The lowest SjvO2 observed was 28%. In all 8 cases, the SjvO2 increased, from 47 +/- 10% to 63 +/- 5% after evacuation of the hematoma. Additional data supporting the hypothesis that these secondary insults identified with the SjvO2 monitoring contribute to the patient's neurological injury come from measurement of the extracellular concentrations of lactate and excitatory amino acids in the brain using microdialysis. Lactate concentration increased from 0.9 +/- 0.3 to 2.4 +/- 0.5 mumol/L and glutamate increased from 11.5 +/- 8.5 to 55.0 +/- 10.4 mumol/L during 8 episodes of jugular venous desaturation in 7 of 22 patients monitored with microdialysis. SjvO2 identifies global reductions in cerebral oxygenation due to a variety of causes, and is useful as a monitor for secondary insults in patients with severe head injury.

Adult↗

PubMed1995

Clinical evaluation of a miniature strain-gauge transducer for monitoring intracranial pressure.

In 25 patients, we evaluated the accuracy of a new miniature strain-gauge transducer developed for the measurement of intracranial pressure (ICP). The ICP in each patient was measured with the intraventricular, miniature strain-gauge transducer, and that value was compared with the ICP measured with a ventriculostomy catheter coupled to an external strain-gauge transducer. From the two monitors, 2218 simultaneous measurements of ICP were obtained. The average ICP measured with the miniature strain-gauge transducer was 15.9 +/- 10.0 mm Hg (range, -3 to 104 mm Hg). The ICP measured with the ventriculostomy-catheter transducer averaged 15.4 +/- 10.1 mm Hg (range, -9 to 104 mm Hg). A highly significant correlation was found over the wide range of pressures observed (n = 2218, r = 0.97, P < 0.001). The average difference between the two measurements of the ICP was 0.5 +/- 2.6 mm Hg, and the differences were equally positive and negative, demonstrating no consistent bias. The two values for the ICP were within 2 mm Hg of each other on 63% of the measurements and within 4 mm Hg of each other on 89% of the measurements. The average zero drift of the miniature strain-gauge transducer, measured at ambient pressure after removal of the catheter, was 0.2 +/- 0.5 mm Hg. The results indicate that this miniature strain-gauge transducer is highly accurate and stable and that it is a reliable alternative to a ventriculostomy for monitoring the ICP.

Adult↗

PubMed1995

Early detection of delayed traumatic intracranial hematomas using near-infrared spectroscopy.

Delayed intracranial hematomas are an important treatable cause of secondary brain injury in patients with head trauma. Early identification and treatment of these lesions, which appear or enlarge after the initial computerized tomography (CT) scan, may improve neurological outcome. Serial examinations using near-infrared spectroscopy (NIRS) to detect the development of delayed hematomas were performed in 167 patients. The difference in absorbance of light (delta OD) at 760 nm between the normal and the hematoma side was measured serially during the first 3 days after injury. Twenty-seven (16%) of the patients developed a type of late hematoma: intracerebral hematoma in eight, extracerebral hematoma in six, and postoperative hematoma in 13 patients. Eighteen of the delayed hematomas caused significant mass effect and required surgical evacuation. The hematomas appeared between 2 and 72 hours after admission. In 24 of the 27 patients, a significant increase (> 0.3) in the delta OD occurred prior to an increase in intracranial pressure, a change in the neurological examination, or a change on CT scan. A favorable outcome occurred in 67% of the patients with delayed hematomas, which suggests that early diagnosis using NIRS may allow early treatment and reduce secondary injury caused by delayed hematomas.

Adolescent↗

PubMed1994

Lateral cortical impact injury in rats: cerebrovascular effects of varying depth of cortical deformation and impact velocity.

Intracranial pressure (ICP), blood pressure (BP), cerebral perfusion pressure (CPP), and cortical perfusion (LDF) of the contralateral parietal cortex were measured after cortical impact injury in 36 rats. Changes in these physiologic parameters were compared using analysis of variance to a group of 11 rats who received a sham impact. In one series of experiments, the velocity and duration of the impact injury were kept constant, and the severity of the injury was determined by varying the depth of cortical deformation from 2 to 3 mm. The peak pressure inside the skull was directly related to the depth of cortical deformation, and was 93 +/- 16, 182 +/- 18, and 268 +/- 57 mm Hg with the 2, 2.5, and 3 mm deformation, respectively, when the impact velocity was 5 m/sec. With the 2 mm depth injury, there was a transient decrease in BP (p < 0.05) and a 12% decrease in LDF after the impact. With the 2.5 mm depth injury, a small transient increase in ICP and decrease in BP and a 30% decrease in LDF occurred (p < 0.05). ICP then gradually increased throughout the 8 h experiment, becoming significantly greater than the sham-injured animals by 5 h after the impact. LDF gradually returned toward normal throughout the experiment. With the 3 mm depth injury, a marked transient increase in ICP (p < 0.05) and BP (p < 0.05) occurred immediately after the impact. The increase in BP lasted < 5 min, and subsequently the BP decreased to approximately 50 mm Hg for the rest of the experiment. The initial marked increase in ICP lasted 15 min and then remained 5-10 mm Hg higher (p < 0.05) than in the sham-injured animals for the rest of the experiment. LDF decreased by an average of 50% (p < 0.05) immediately after the impact and remained lower than that of the sham-injured animals for the rest of the experiment. In another series of experiments, the depth of cortical deformation was kept constant at 2.5 mm, and the severity of the injury was determined by varying the velocity from 1 to 5 m/sec. The peak ICP was significantly related to the impact velocity, averaging 45 +/- 12, 66 +/- 9, and 182 +/- 18 mm Hg with the 1, 3, and 5 m/sec impact injuries, respectively. The 1 m/sec impact had no effect on ICP and only a transient decrease in BP.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗

PubMed1994

Jugular venous desaturation and outcome after head injury.

Early experience with continuous monitoring of jugular venous oxygen saturation (SjvO2) suggested that this technology might allow early identification of global cerebral ischaemia in patients with severe head injury. The purpose of the present study was to examine the relationship between episodes of jugular venous desaturation and neurological outcome. One hundred and sixteen severely head-injured patients had continuous monitoring of SjvO2 during days 1-5 after injury. Episodes of jugular venous desaturation (SjvO2 < 50% for more than 10 minutes) were prospectively identified, and the incidence of desaturation was correlated with neurological outcome: 77 episodes of desaturation occurred in 46 of the 116 patients; 27 had one episode and 19 had multiple episodes of desaturation. The causes of these episodes were systemic (n = 36), cerebral (n = 35), or both (n = 6). Most of the episodes were less than 1 hour in duration, and it is probable that many of them would not have been detected without continuous measurement of SjvO2. Episodes of desaturation were most common on day 1 after injury, and were twice as common in patients with a reduced cerebral blood flow as in patients with a normal or elevated cerebral blood flow. The occurrence of jugular venous desaturation was strongly associated with a poor neurological outcome. The percentage of patients with a poor neurological outcome was 90% with multiple episodes of desaturation and 74% in patients with one desaturation, compared to 55% in patients with no episodes of desaturation. When adjusted for all co-variates that were found to be significant, including age, Glasgow coma score, papillary reactivity, type of injury, lowest recorded cerebral perfusion pressure, and highest recorded temperature, the incidence of desaturation remained significantly associated with a poor outcome. Although a cause and effect relationship with outcome cannot be established in this study, the data suggest that monitoring SvO2 might allow early identification and therefore treatment of many types of secondary injury to the brain.

Adolescent↗

PubMed1994

Brain blood flow responses to indomethacin during hemorrhagic hypotension in newborn piglets.

Indomethacin has been shown to reduce cerebral blood flow and cerebral blood flow velocities in newborn infants and animals of various species. To answer the question of whether there may be a compromise of cerebral perfusion in hypotensive infants who have been treated with indomethacin, cerebral blood flow and cerebral vascular resistance were determined in 10 control and 16 indomethacin-treated 1-day-old piglets during (1) steady state conditions; (2) 10 min after the administration of saline or a 0.2-mg/kg dose of indomethacin; (3) 1 h after saline or indomethacin administration, and (4) 10 min after induction of moderate hemorrhagic hypotension. Mean arterial blood pressures increased immediately after the infusion of indomethacin in the experimental group. Cerebral blood flows did not change throughout the study despite hemorrhagic hypotension in controls; cerebral blood flows were significantly decreased 10 min after indomethacin infusion in the experimental animals. However, total and regional cerebral blood flows were not further decreased in the presence of moderate hypotension. Cerebral vascular resistance increased 10 min after indomethacin infusion but returned to steady state 1 h following the indomethacin dose. These results suggest that indomethacin lowers baseline cerebral blood flow, but does not impair cerebrovascular regulatory responses during acute, moderate hemorrhagic hypotension in the newborn piglet.

Animals↗

PubMed1994

Sensitivity and specificity of fluid-blood levels for coagulopathy in acute intracerebral hematomas.

PURPOSE: To characterize the imaging features of intracerebral hemorrhages in coagulopathies that alter prothrombin time or partial thromboplastin time. METHODS: A fluid-blood level was defined as a horizontal interface between hypodense bloody serum layered above hyperdense settled blood. The prevalence of fluid-blood levels in acute intracerebral hemorrhages was determined on third-generation CT scans in 32 patients with elevation in prothrombin time or partial thromboplastin time. This was compared with the frequency of fluid-blood levels in 185 patients with intracerebral hemorrhage in which there was no laboratory evidence of coagulopathy. RESULTS: The probability of finding a fluid-blood level in an intracerebral hemorrhage of a patient with abnormal prothrombin time or partial thromboplastin time was 59% (sensitivity). The probability that there will be no fluid-blood level in a patient with a normal prothrombin time and partial thromboplastin time was 98% (specificity). CONCLUSION: Fluid-blood levels in acute intracerebral hemorrhage are moderately sensitive to the presence of coagulopathy (ie, abnormal prothrombin time and partial thromboplastin time) and highly specific for this condition. Thus, an intracerebral hemorrhage with a fluid-blood level should prompt a thorough search for coagulopathy because early treatment of this condition may improve the 40% mortality in these patients. Caution should be used to distinguish the horizontal interface of a fluid-blood level from a clot with a flat top. A decubitus CT is useful in these rare instances.

Aged↗

PubMed1993

Spectral analysis of corticomotor evoked potentials in spinal cord injury. Part 1. Acute studies.

A model of graded spinal cord injury using ischaemia has been developed by using balloon occlusion of the abdominal aorta in rabbits. This model has been used to test pharmacological agents thought to provide protection against spinal cord injury based on changes in corticomotor evoked potentials (CMEPs). These highly reproducible signals are percutaneously recorded from the spinal cord in response to cortical stimulation and accurately reflect the degree of residual spinal cord function. The present study focused on the power spectra of CMEPs to clarify alterations in post-injury signals. This added dimension of previously unreported CMEP analysis will augment future applications of the current model.

Acute Disease↗