1/17. Brain damage following collapse of a polyvinyl tube: elasticity and permeability of the cuff.A 13-year-old boy undergoing tympanoplasty lasting 3 1/2 hours developed serious airway obstruction at the end of surgery leading to permanent brain damage. It appeared that the no. 7 Portex "blue line" endotracheal tube had collapsed under the cuff. This was concluded because deflation of the cuff had promptly relieved the obstruction of the airway. Further support for this conclusion was the finding that shortly after extubation the inflation of 8 ml air caused the tube to collapse. Collapse of these tubes cannot normally be produced unless they have been made to collapse shortly before. Investigation of such tubes in vitro at 37 degrees C showed that overinflation of the cuff caused a symmetrical collapse of the tube wall along the x-ray opaque blue line. The collapse occurred with cuff pressures varying from 310 mmHg up to 460 mmHg for tubes from different batches. During anaesthesia with 66% nitrous oxide, this gas together with carbon dioxide were found to diffuse into the cuff at steady rates of 3.69 vol % and 0.36 vol % per hour, respectively. Corresponding increases in intracuff volumes were found. It is advised that disposable tubes should be carefully inspected before use and that endotracheal cuffs should be deflated periodically during anaesthesia to avoid excessive rise in cuff pressure.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
2/17. Hypoxic-ischemic leukoencephalopathy in man.Three cases of hypoxic-ischemic leukoencephalopathy were studied. In two patients, the neurologic disorder followed drug overdosage; in the third, the apparent precipitating event was a postoperative myocardial infarction complicated by circulatory insufficiency. All patients were deeply unresponsive, with varying reflex patterns. In all three cases, the brain showed extensive symmetrical necrotic lesions of the central white matter, with minimal damage to gray matter structures. The lesions in case 3 showed, in addition, vascular necrosis and ring hemorrhages. Common to all cases was a prolonged period of hypoxemia, hypotension, and elevated venous pressure. acidosis occurred in two. These observations and analysis of previous reports of similar cases suggest that leukoencephalopathy tends to occur when the hypoxemia is prolonged and is associated with periods of hypotension and metabolic imbalance.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
3/17. Hypothalamic hamartoma and epilepsy in children: illustrative cases of possible evolutions.The progresses of neuroimaging have allowed an earlier detection of hypothalamic hamartoma in children presenting with gelastic or dacrystic seizures. Associated symptoms can include other types of seizures, precocious puberty, and behavioral or cognitive deterioration. Combination of all these features is not constant and, when present, their evolution may be variable. When epilepsy proves intractable, surgery may be a solution but is not without risks. Therefore, it can only be justified on the basis of a considerable degree of certainty on the progressive character of the disorder, both in terms of epilepsy and global development. Even though epilepsy is a major and usually the most important problem, it is not always possible to predict its course and to be able to evaluate its potential effects on development. Available data suggests that deterioration is partly related to the epileptogenic activity. We reviewed data from 16 personal cases and discussed the possible evolutions of the epilepsy syndrome on the basis of 6 illustrative cases and a review of the literature. We point out that seizures may start early in life and evolve either towards a catastrophic encephalopathy or may be transiently severe and will progressively settle down. Intermediate situations also exist as well as cases presenting with a mild epilepsy. In almost all cases cognitive difficulties are present and may be associated with behavioral disturbances. They are of variable severity, usually in relation to the severity of the epilepsy and the evolution of the EEG abnormalities. Some of our cases also illustrate that, in young children whose seizures are limited to "a sensation of a pleasant feeling", "a pressure to laugh" or "smiling", early detection of the hamartoma may still be difficult and the epilepsy pattern may be misdiagnosed as an epilepsy temporal or frontal origin. Detailed analysis of the electro-clinical evolution of representative cases highlights the variable expression of the epilepsy syndrome and renders difficult any dogmatic position on early surgery. However, recent data suggests that a surgical solution must be sought early. prospective studies are needed to evaluate, not only outcome in terms of control the seizures without unacceptable side effects but also on the evolution of the cognitive and behavioral profile of children with HH and epilepsy are needed.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
4/17. Is there an upper limit of intracranial pressure in patients with severe head injury if cerebral perfusion pressure is maintained?Authors of recent studies have championed the importance of maintaining cerebral perfusion pressure (CPP) to prevent secondary brain injury following traumatic head injury. Data from these studies have provided little information regarding outcome following severe head injury in patients with an intracranial pressure (ICP) greater than 40 mm Hg, however, in July 1997 the authors instituted a protocol for the management of severe head injury in patients with a glasgow coma scale score lower than 9. The protocol was focused on resuscitation from acidosis, maintenance of a CPP greater than 60 mm Hg through whatever means necessary as well as elevation of the head of the bed, mannitol infusion, and ventriculostomy with cerebrospinal fluid drainage for control of ICP. Since the institution of this protocol, nine patients had a sustained ICP greater than 40 mm Hg for 2 or more hours, and five of these had an ICP greater than 75 mm Hg on insertion of the ICP monitor and later experienced herniation and expired within 24 hours. Because of the severe nature of the injuries demonstrated on computerized tomography scans and their physical examinations, these patients were not aggressively treated under this protocol. The authors vigorously attempted to maintain a CPP greater than 60 mm Hg with intensive fluid resuscitation and the administration of pressor agents in the four remaining patients who had developed an ICP higher than 40 mm Hg after placement of the ICP monitor. Two patients had an episodic ICP greater than 40 mm Hg for more than 36 hours, the third patient had an episodic ICP greater than of 50 mm Hg for more than 36 hours, and the fourth patient had an episodic ICP greater than 50 mm Hg for more than 48 hours. On discharge, all four patients were able to perform normal activities of daily living with minimal assistance and experience ongoing improvement. Data from this preliminary study indicate that intense, aggressive management of CPP can lead to good neurological outcomes despite extremely high ICP. Aggressive CPP therapy should be performed and maintained even though apparently lethal ICP levels may be present. Further study is needed to support these encouraging results.- - - - - - - - - - ranking = 5keywords = pressure (Clic here for more details about this article) |
5/17. Judo as a possible cause of anoxic brain damage. A case report.The rules of judo provide for strangulation techniques in which the blood supply to the brain is blocked by pressure on the carotid arteries; such techniques produce anoxia and possible unconsciousness if the victim fails to submit. A case is presented of a patient with signs of anoxic brain damage, with psychometric investigation showing memory disturbance consistent with a left temporal lobe lesion. This patient had been frequently strangled during his career as a judo player; it is suggested that such frequent strangulation was the cause of the damage. Such an observation indicates the need for caution in the use of such techniques.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
6/17. spasm index in subarachnoid haemorrhage: consequences of vasospasm upon cerebral blood flow and oxygen extraction.A spasm index, defined as transcranial Doppler detected flow velocity in the middle cerebral artery divided by regional cortical cerebral blood flow (CBF), was used on 24 patients with subarachnoid haemorrhage (SAH). The aim was to estimate degree and time course of vasospasm, even in cases with great day-to-day variation in CBF, and correlate to CBF and oxygen extraction. All patients showed increase in spasm indices with peak index in the second or third week. The index seemed stable in spite of day-to-day fluctuations in CBF. Severe vasospasm were associated with poor clinical condition, reduced CBF (less than 30) and high AVDO2. The same picture could be seen with minor degree of vasospasm, probably, in some cases, due to high intracranial pressure. The results suggest that the spasm index is useful in monitoring patients with subarachnoid haemorrhage, and that severe vasospasm has a negative influence on clinical condition, CBF and oxygen extraction.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
7/17. Neurological outcome after a severe herpes simplex encephalitis treated with acyclovir and beta-interferon. time course of intracranial pressure.A severe herpes simplex encephalitis with documented intra-cerebral lesions and brain edema was treated successfully with acyclovir and beta-interferon. The increase in intracranial pressure during the second week was well controlled by ICP monitoring. life-threatening pressure peaks were avoided through the use of thiopental, osmodiuretics, TRIS, and lidocaine.- - - - - - - - - - ranking = 3keywords = pressure (Clic here for more details about this article) |
8/17. A brief neurobehavioral exam useful for early detection of postoperative complications in neurosurgical patients.This article describes data from 11 patients evaluated before and after neurosurgical intervention for treatment of brain tumor, subdural hematoma and hydrocephalus. The Neurobehavioral Cognitive Status Examination (NCSE) was administered pre- and postoperatively. Improvement was documented by the NCSE in 6 of the 11 patients. In the remaining five patients, there was evidence of deterioration in cognitive functioning. After clinical and diagnostic re-evaluation by the physician, four patients had repeat operations. Follow-up evaluation after the second operation was useful in determining treatable and non-treatable causes of progressive cognitive deterioration. In these patients use of the NCSE may have expedited effective diagnostic evaluation and subsequently improved patient care. Such instruments have clinical utility since they are easily administered, pragmatic, and objectify subtle changes in cognitive functioning which may be early signs of increased intracranial pressure or complications of surgery.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
9/17. Neurological manifestations in abused children who have been shaken.Four infants with the 'shaken infant syndrome' are described. None had skull fractures and only one had a subdural hematoma. All had extensive retinal and pre-retinal hemorrhages. Follow-up computerized tomography showed severe brain atrophy, multiple hypodense areas and ventricular enlargement. Three of the patients suffered severe, permanent brain damage, with mental retardation, spasticity and blindness. It is suggested that the underlying pathogenesis of this syndrome is acutely increased intrathoracic pressure, transmitted into the head to cause multiple venous infarctions. Retinal and pre-retinal hemorrhages are cardinal features of this syndrome and their presence should raise the suspicion of this form of battering in the absence of the 'classical' signs of battering.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
10/17. Evidence suggestive of diffuse brain damage following cardiac operations.In 37 patients regional cerebral blood flow (rCBF) was measured by single photon emission computerised tomography (SPECT) after inhalation of xenon-133 before and within the first 10 days after open heart surgery for acquired or congenital heart disease. None of the patients had motor deficits postoperatively and no focal abnormalities were disclosed by the rCBF tomograms. However, rCBF was generally reduced and mean CBF fell from a normal value of 53.5 to 44.7 ml/100 g X min (p less than 0.001). Changes in rCBF occurred uniformly throughout the brain. The reduction in CBF correlated positively with increasing years (p less than 0.05), duration of extracorporeal circulation (p less than 0.05), and low mean arterial blood pressure during the bypass (p less than 0.02). It was generally more pronounced after valve replacement than after coronary bypass (p less than 0.16). In 11 patients investigated 1 year after surgery CBF remained slightly reduced, 50.5 ml/100 g X min (p less than 0.05). No CBF reduction occurred in a control group of 15 patients who underwent carotid endarterectomy or extracranial-intracranial shunt operations. The findings are consistent with the suggestion that the extracorporeal circulation causes early postoperative central nervous system dysfunction.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
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