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Biomedical subjects

S M Toutant

Publications and source records attributed to S M Toutant.

9 recordsLinked to original sources
PubMed1984

Traumatic acute epidural hematoma: unrecognized high lethality in comatose patients.

A series of 51 comatose patients suffering traumatic epidural hematoma after closed head injury is reviewed. This prospective series was accumulated from the National Pilot Traumatic Coma Data Bank during a 2-year period and represents 9% of all patients entered into the Data Bank. The overall mortality was 41%, with 4% remaining in the vegetative state. Fifty per cent of these patients, all of whom were in coma, also had an associated intracerebral contusion. There was no difference in outcome with regard to sex, mode of injury, or the presence or absence of contusion or shift on the computed tomographic (CT) scan. The motor score immediately before operation was the most powerful preoperative predictor of outcome. Sixty-seven per cent or two-thirds of the patients with a motor score of 4, 5, or 6 on the Glasgow coma scale had a satisfactory outcome at last follow-up examination. In contrast, in patients with a motor score of 3 or less, two-thirds either died or remained in a vegetative state. The acute traumatic epidural hematoma is often lethal in the comatose patient. We recommend early evacuation of epidural hematomas, i.e., when they are first noted on the CT scan, rather than waiting for clinical motor deterioration.

Acute Disease↗
PubMed1984

Absent or compressed basal cisterns on first CT scan: ominous predictors of outcome in severe head injury.

The relationship of outcome to the appearance of the basal cisterns as seen on initial computerized tomography (CT) scanning was assessed in 218 consecutive severely head-injured patients entered into the second phase of the National Pilot Traumatic Coma Data Bank. Outcome could be directly related to the status of the basal cisterns on the initial CT scan. The mortality rates were 77%, 39%, and 22% among those with absent, compressed, and normal basal cisterns, respectively. This association between cisterns and outcome was shown to be strong after adjusting for Glasgow Coma Scale (GCS) score (p less than 0.001). The state of the cisterns was more important for those with higher GCS scores (scores 6 to 8) than for those with lower scores (scores 3 to 5). Patients with GCS scores of 6 to 8, with cisterns absent or not visualized, suffered nearly a fourfold additional risk of poor outcome, compared to those with normal cisterns. This indicates that the status of the cisterns can be used as an early noninvasive method of identifying patients at high risk of death or severe disability, in whom the initial neurological examination would potentially suggest otherwise.

Brain Injuries↗
PubMed1984

A model for predicting delayed intracranial hypertension following severe head injury.

A graph is presented for predicting delayed intracranial hypertension (intracranial pressure (ICP) greater than 30 mm Hg) for severely head-injured patients, based on a logistic regression model. Data gathered during the first 24 hours of patient observation are used to predict patient status during the subsequent 48 hours. The best predictor out of 10 factors analyzed was the peak ICP level during the first 24 hours (p less than 0.0001). Other predictors used in the final model were the presence of hypotension (p = 0.045) and abnormal ventricles--defined as ventricles which were either absent, small, or enlarged (p = 0.086). Error rates of 24% and 20% were obtained initially and by means of a separate cross-validation group, respectively. Use of a conservative cut point (25% estimated chance of developing excess ICP) for designating high-risk patients provided a procedure with sensitivity of 86% to 89% for the two groups.

Brain Injuries↗
PubMed1983

Cerebral blood flow during high frequency ventilation in cats.

Cerebral blood flow (CBF) was compared during conventional low frequency ventilation (LFV) [tidal volume 15 ml/kg, respiratory rate 12] and high frequency ventilation (HFV) [tidal volume 3 ml/kg, respiratory rate 100] in normal cats. The intra-arterial 133Xenon technique was used to determine CBF. No significant difference in CBF was present between the 2 groups. The mean CBF was 46.6 +/- 14.2 ml/dl X min during LFV and 44.4 +/- 12.2 ml/dl X min during HFV. Additionally, mean arterial pressure, CVP, intracranial pressure (ICP), cerebral perfusion and airway pressures were not significantly different between the groups. HFV has little effect on cerebral hemodynamics.

Animals↗
PubMed1981

Upright patient positioning in the management of intracranial hypertension.

Utilizing either a subarachnoid screw or an intraventricular cannula, intracranial pressure was continuously monitored in 24 patients with established or potential neurological impairment of various etiologies. Marked diminution in intracranial pressure was observed in the sitting or semisitting position in the 13 patients with documented intracranial hypertension as well as in the 11 in whom intracranial pressure was not elevated. This sustained effect was noted even when superimposed on intensive medical management of intracranial hypertension.

Adolescent↗
PubMed1981

The effects of high-frequency positive-pressure ventilation on intracranial pressure and brain surface movement in cats.

Compared to traditional, low-frequency ventilation (LFV), mechanical ventilation at high frequencies (60-200 breaths/min) and low tidal volumes (HFV) is known to: 1) eliminate respiratory-synchronous variations in blood pressure; 2) minimize ventilatory effects on the cardiovascular system; 3) reduce peak airway pressures; and 4) suppress spontaneous respiratory efforts. Since these and other properties may make HFV useful in patients with acute intracranial pathology, we studied the effects of HFV on intracranial pressure (ICP) in cats. Compared with LFV (rate 11/min, tidal volume equals 15 ml/kg), HFV (rate 100/min, VT equals 3.3 ml/kg) had little effect on mean arterial pressure, heart rate, right atrial pressure, mean ICP or mean cerebral perfusion pressures, even if baseline ICP was raised using an epidural balloon. However, HFV effectively eliminated ventilator-linked fluctuations in both blood pressure and ICP, and at all levels of mean ICP studied (4.8, 15, and 30 torr), significantly reduced the peak ICP seen during a single respiratory cycle. The reduction in ICP fluctuation and peak pressure was more pronounced as intracranial complicance fell. However, the physiologic significance of such a change in the ICP pressure waveform is unknown. Because of the observed influence of HFV on ICP fluctuations, we also examined its effects on the physical movement of the exposed brain, using a non-contact, inductive displacement measuring device. During LFV, the cortical surface moved "in and out" by 0.36 plus or minus 0.1 (plus or minus SD) mm, a distance sufficient to make microscopic focusing difficult. Changing to HFV reduced surface movement to 0.05 plus or minus 0.01 mm, producing a very stable surface. These results suggested that HFV may play a very important role in the intraoperative management oif patients undergoing certain neurosurgical procedures, particularly those requiring microsurgical techniques where reduced brain movement may facilitate surgery.

Animals↗