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Biomedical subjects

R G Grossman

Publications and source records attributed to R G Grossman.

At least 19 recordsLinked to original sources
PubMed1992

Cerebral blood flow, arteriovenous oxygen difference, and outcome in head injured patients.

Cerebral blood flow (CBF) and other physiological variables were measured repeatedly for up to 10 days after severe head injury in 102 patients, and CBF levels were related to outcome. Twenty five of the patients had a reduced CBF [mean (SD) 0.29 (0.05) ml/g/min]; 47 had a normal CBF, (0.41 (0.10) ml/g/min); and 30 had a raised CBF (0.62 (0.14) ml/g/min). Cerebral arteriovenous oxygen differences were inversely related to CBF and averaged 2.1 (0.7) mumol/ml in the group with reduced CBF, 1.9 (0.5) mumol/ml in the group with normal CBF, and 1.6 (0.4) mumol/ml in the group with raised CBF. Patients with a reduced CBF had a poorer outcome than patients with a normal or raised CBF. Mortality was highest in patients with a reduced CBF, and was 32% at three months after injury, whereas only 21% of the patients with a normal CBF and 20% of the patients with a raised CBF died. There were no differences in the type of injury, initial score on the Glasgow Coma Scale, mean intracranial pressure (ICP), highest ICP, or the amount of medical treatment required to keep the ICP less than 20 mm Hg in each group. Systemic factors did not significantly contribute to the differences in CBF among the three groups. A logistic regression model of the effect of CBF on neurological outcome was developed. When adjusted for variables which were found to be significant confounders, including age, initial Glasgow Coma Score, haemoglobin concentration, cerebral perfusion pressure and cerebral metabolic rate of oxygen, a reduced CBF remained significantly associated with an unfavourable neurological outcome.

Adult↗
PubMed1992

Dietary nonprotein calories and cerebral infarction size in rats.

BACKGROUND AND PURPOSE: Conventional diets may cause hyperglycemia in patients with neurological injuries. The purpose of this study was to examine the effect on the severity of cerebral infarction of replacing carbohydrates as the primary dietary source of nonprotein calories. METHODS: Sixty-nine Long-Evans rats were either fasted for 24 hours, fed isocaloric amounts of a control diet containing 51.5% of the calories as carbohydrates, or fed one of five experimental diets before middle cerebral artery occlusion for 45 minutes. In the experimental diets, 60% of the carbohydrate calories were replaced with one or more of the following substrates: 1,3-butanediol, triacetin, tributyrin, and long- and medium-chain triglycerides. RESULTS: The plasma glucose concentration in the fasted animals was 6.4 +/- 1.1 mumol/ml. In the animals receiving the control diet, which contained the greatest number of carbohydrate calories, plasma glucose was 9.1 +/- 1.4 mumol/ml. The 1,3-butanediol diet resulted in an intermediate plasma glucose concentration averaging 7.8 +/- 1.3 mumol/ml. Plasma beta-hydroxybutyrate levels were elevated in the fasted group and with the 1,3-butanediol diet. Plasma acetate levels were increased with the diets supplemented with triacetin. The smallest infarct volume (53 +/- 43 mm3) was found in the fasted group and the largest (162 +/- 56 mm3) in the control diet group. Infarct volumes that were significantly smaller were found with the 1,3-butanediol diet (98 +/- 41 mm3) and with the triacetin/tributyrin diet (105 +/- 53 mm3). The volume of the infarct was directly related to the plasma glucose concentration before ischemia (n = 69, r = 0.47, p less than 0.01), but not to plasma lactate, ketone body, or acetate levels. CONCLUSIONS: It may be possible to develop a diet for patients with neurological injuries using noncarbohydrate calorie sources, such as 1,3-butanediol, triacetin, or tributyrin, that would supply systemic caloric and protein requirements without the adverse effect of conventional diets.

Animals↗
PubMed1992

Effect of head elevation on intracranial pressure, cerebral perfusion pressure, and cerebral blood flow in head-injured patients.

The traditional practice of elevating the head in order to lower intracranial pressure (ICP) in head-injured patients has been challenged in recent years. Some investigators argue that patients with intracranial hypertension should be placed in a horizontal position, the rationale being that this will increase the cerebral perfusion pressure (CPP) and thereby improve cerebral blood flow (CBF). However, ICP is generally significantly higher when the patient is in the horizontal position. This study was undertaken to clarify the issue of optimal head position in the care of head-injured patients. The effect of 0 degree and 30 degrees head elevation on ICP, CPP, CBF, mean carotid pressure, and other cerebral and systemic physiological parameters was studied in 22 head-injured patients. The mean carotid pressure was significantly lower when the patient's head was elevated at 30 degrees than at 0 degrees (84.3 +/- 14.5 mm Hg vs. 89.5 +/- 14.6 mm Hg), as was the mean ICP (14.1 +/- 6.7 mm Hg vs. 19.7 +/- 8.3 mm Hg). There was no statistically significant change in CPP, CBF, cerebral metabolic rate of oxygen, arteriovenous difference of lactate, or cerebrovascular resistance associated with the change in head position. The data indicate that head elevation to 30 degrees significantly reduced ICP in the majority of the 22 patients without reducing CPP or CBF.

Adult↗
PubMed1992

Continuous monitoring of jugular venous oxygen saturation in head-injured patients.

The continuous measurement of jugular venous oxygen saturation (SjvO2) with a fiberoptic catheter is evaluated as a method of detecting cerebral ischemia after head injury. Forty-five patients admitted to the hospital in coma after severe head injury had continuous and simultaneous monitoring of SjvO2, intracranial pressure, arterial oxygen saturation, and end-tidal CO2. Cerebral blood flow, cerebral metabolic rates of oxygen and lactate, arterial and jugular venous blood gas levels, and hemoglobin concentration were measured every 8 hours for 1 to 11 days. Whenever SjvO2 dropped to less than 50%, a standardized protocol was followed to confirm the validity of the desaturation and to establish its cause. Correlation of SjvO2 values obtained by catheter and with direct measurement of O2 saturation by a co-oximeter on venous blood withdrawn through the catheter was excellent after in vivo calibration when there was adequate light intensity at the catheter tip (176 measurements: r = 0.87, p less than 0.01). A total of 60 episodes of jugular venous oxygen desaturation occurred in 45 patients. In 20 patients the desaturation value was confirmed by the co-oximeter. There were 33 episodes of desaturation in these 20 patients, due to the following causes: intracranial hypertension in 12 episodes, hypocarbia in 10, arterial hypoxia in six, combinations of the above in three, systemic hypotension in one, and cerebral vasospasm in one. The incidence of jugular venous oxygen desaturations found in this study suggests that continuous monitoring of SjvO2 may be of clinical value in patients with head injury.

Adult↗
PubMed1992

Cerebral blood flow, AVDO2, and neurologic outcome in head-injured patients.

A reduced cerebral blood flow (CBF) and a widened arteriovenous oxygen difference (AVDO2) almost always have been associated with a poor neurologic outcome. The literature on this relationship is reviewed. A logistic regression analysis model of the effect of CBF on neurologic outcome was developed, which was adjusted for various confounding factors. CBF remained significantly associated with neurologic outcome-despite these adjustments.

Adult↗
PubMed1992

Blood flow and metabolic therapy in CNS injury.

A hypermetabolic state, consisting of increased resting energy expenditure, excessive protein wasting, and hyperglycemia, occurs in patients with a severe head injury. The hypermetabolism can affect survival by rapidly resulting in protein-calorie malnutrition (increased energy expenditure and protein wasting) and may adversely affect neurological recovery by altering the microenvironment of the injured brain (hyperglycemia).

Animals↗
PubMed1991

Evaluation of the Leeds prognostic score for severe head injury.

According to the Leeds scale for identifying severely head injured patients, death can be predicted with certainty within 12 hours of admission if a patient has a score higher than 13. The withdrawal of treatment from such patients has considerable moral and legal implications. Therefore, to test the reliability of the Leeds scale, it was applied to two patient populations with severe head injuries (479 retrospectively, 131 prospectively). In both groups the scale failed to predict mortality with 100% accuracy: in the first group, 16 of 23 (69.6%) of the patients with a score of more than 13 (and therefore predicted to die) died, and 380 (83.3%) of 456 patients with scores of 13 or less survived; the data for the second group are 6/10 (60%) and 98/121 (81%), respectively. The findings suggest that the Leeds prediction model is not infallible and should be applied cautiously when making decisions about the early termination of care in severely head injured patients.

Adolescent↗
PubMed1979

Impaired recognition memory after head injury.

A continuous recognition memory task employing 120 line drawings of familiar stimuli was administered to patients recovering from closed head injury of varying severity and control patients. Mildly injured patients obtained significantly more correct responses, and higher memory sensitivity (d') values than moderately and severely injured patients who performed similarly. The measure of response criterion, c, was significantly lower in patients with injury of moderate severity when compared to mildly injured cases and control patients. Controls and mildly injured patients did not differ in their performance. In general, the total correct responses most impressively differentiated head injured patients with measurable coma duration as more than two-thirds had scores below the control group. Group differences in hits, false alarms and misses were examined also. Age and education, skull fracture, and hematoma were generally unrelated to any of the measures, whereas coma duration was significantly related to most measures of mnemonic efficiency.

Adolescent↗
PubMed1979

The Galveston Orientation and Amnesia Test. A practical scale to assess cognition after head injury.

The Galveston Orientation and Amnesia Test (GOAT) was developed to evaluate cognition serially during the subacute stage of recovery from closed head injury. This practical scale measures orientation to person, place, and time, and memory for events preceding and following the injury. The distribution of test scores in 50 patients who had recovered from a mild closed head injury was used to define the range of variation in performance and to analyze the effects of demographic factors. In a validity study of 52 closed head-injured patients, the duration of impaired GOAT scores was strongly related to the acute neurosurgical ratings of eye opening, motor responding, and verbal responding on the Glasgow Coma Scale. Duration of post-traumatic amnesia, as defined by the persistence of defective GOAT scores, was longer in patients with computed tomographic evidence of diffuse or bilateral brain injury as compared to cases with focal unilateral lesions. Serial GOAT scores were also predictive of long term level of recovery. Review of the brief cognitive test literature disclosed that several techniques have adequate validity data substantiating their use in the detection of dementia in geriatric, psychiatric, and medical populations. Recommendations for the clinical application of the various brief cognitive tests are discussed.

Adolescent↗
PubMed1979

Radionuclide cerebral angiography and the timing of aneurysm surgery.

Forty-five patients with subarachnoid hemorrhage due to verified intracranial aneurysms were studied prospectively to determine whether delaying operations in those patients with abnormal cerebral perfusion, assessed by radionuclide dynamic scanning, would lower case management mortality. Twenty-nine patients had intracranial operations when their radionuclide dynamic scans demonstrated normal perfusion. The one death in this group occurred in a patient who suffered a massive hemorrhage during operation as the bone flap was elevated. There were no instances of delayed spasm after operation. Of the 16 remaining patients who were treated without operation, 5 died. Only 1 of these deaths resulted from recurrent hemorrhage. This patient had normal cerebral perfusion but was not operated upon because of severe associated medical problems. Cerebral infarction occurred in 10 of the 16 unoperated patients, all of whom had persistently decreased cerebral perfusion. Four of these patients died of their infarctions or related causes. Although a trend related vessel caliber as seen on arteriograms and perfusion delay seen on dynamic scanning, individual exceptions were numerous. This study shows that radionuclide scanning, a safe procedure, is useful for identifying two types of patients: those with normal perfusion prone to rebleeding in whom an early operation is safe and those in whom perfusion is decreased. The latter group is prone to cerebral infarction, but rebleeding from the aneurysm is unlikely. Operation should be delayed in these patients until cerebral perfusion returns to normal or for several weeks if cerebral perfusion remains diminished.

Adult↗
PubMed1979

Long-term neuropsychological outcome of closed head injury.

Long-term recovery from severe closed head injury was investigated in predominantly young adults whose Glasgow Coma score was 8 or less at the time of admission. Of the 27 patients studied (median follow-up interval of 1 year), 10 attained a good recovery, 12 were moderately disabled, and five were severely disabled. In contrast to previous studies suggesting that intellectual ability after severe closed head injury eventually recovers to a normal level, our findings showed that residual intellectual level, memory storage and retrieval, linguistic deficit, and personal social adjustment corresponded to overall outcome. All severely disabled patients and several moderately disabled patients exhibited unequivocal cognitive and emotional sequelae after long follow-up intervals. Analysis of persistent neuropsychological deficit in relation to neurological indices of acute injury severity demonstrated the prognostic significance of oculovestibular deficit.

Adolescent↗
PubMed1979

Monitoring of cortical excitability during induced hypotension in aneurysm operations.

The electrical excitability of the cortex was monitored during craniotomy in 10 patients with ruptured aneurysms, to test their ability to tolerate hypotensive anesthesia. Excitability was assessed by measuring the direct cortical response, a response evoked and recorded from the surface of the brain. Previous animal experiments had shown that this response can be used as an index of cerebral blood flow. In the 10 patients the response progressively declined as the blood pressure was lowered and increased when the pressure was restored. Observation of the direct cortical response during aneurysm operations is a practical method for evaluating the electrophysiological responsiveness of the cortex during hypotension, and the authors suggest that decreases in the amplitude of the response are related to decreased in local cerebral blood flow.

Adult↗
PubMed1978

Behavioral sequelae of closed head injury. A quantitative study.

We determined the profile of behavioral disturbance in relation to closed head injury of graded severity. Patients with severe injuries, as defined by duration of coma and the presence of neurological deficit, were differentiated from a group of mildly injured patients by behavioral ratings that reflected cognitive disorganization, emotional withdrawal, and motor retardation. Neurologic measurements of injury related to the severity of behavioral disturbance included hemiparesis, aphasia, and abnormalities on computerized axial tomography. Agitation during the acute phase of injury was also predictive of residual behavioral disturbance. Hemispheric lateralization of the site of greatest injury had no discernible effect on behavioral sequelae.

Adult↗
PubMed1977

Glial-neural interaction demonstrated by the injection of Na+ and Li+ into cortical glia.

Injection of Na+ or Li+ into cortical glia evokes glial depolarization, discharge of adjacent neurons, and vascular pulsation. The effects can be explained by the extrusion of K+ from glia after cation injection, glial swelling, and the slow removal of the cation from glia. The data suggest that the reduced rate of reuptake of K+ into Na+-loaded glia results in epileptiform firing of neurons, and support the hypothesis that glia function to buffer the environment of neurons.

Action Potentials↗
PubMed1977

Cerebral perfusion, vascular spasm, and outcome in patients with ruptured intracranial aneurysms.

In a retrospective study of 44 patients with verified ruptured intracranial aneurysms, the results of radionuclide cerebral perfusion scintigraphy (dynamic brain scanning) and the presence or absence of arteriographic spasm were correlated with the clinical outcome. The data indicated that patients with normal dynamic scans had a better outcome as a group and following intracranial surgery than those in whom perfusion was reduced. Patients with normal perfusion had a higher incidence of preoperative rebleeding from their aneurysms, while patients with reduced perfusion had a higher incidence of infarction, especially after intracranial surgery. There was no correlation between the presence or absence of arteriographic spasm and the results of the dynamic scans, and nor correlation between the presence of absence of spasm and the outcome of the group as a whole. However, in some individual cases with severe spasm, reduced perfusion on the dynamic scan and a poor outcome were noted. It was concluded that the results of the dynamic scan correlated better with eventual patient outcome than the presence or absence of arteriographic spasm. It is therefore suggested that patients in Grades I and II with normal dynamic scans be operated on promptly to prevent rebleeding, and that surgery in patients in Grades I and II with abnormal dynamic scans be delayed until the dynamic scan returns to normal.

Adolescent↗
PubMed1976

Short-term recognition memory in relation to severity of head injury.

Short-term recognition memory for random shapes was studied in 24 patients with head injury. The severity of head injury as indexed by duration of coma was closely related to impairment in performance. Disruption of short-term recognition memory was associated with neurologic deficit, asphasic disturbance, and signs of brain stem involvement. Performance was not related to association value of the shapes irrespective of linguistic competence. The findings are discussed in relation to recent studies of continuous recognition memory after head injury and hypotheses concerning neurological dysfunction in head injury.

Adolescent↗