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Biomedical subjects

G W Kindt

Publications and source records attributed to G W Kindt.

At least 37 records · Page 2Linked to original sources
PubMed1982

Total pinealectomy by an occipital parasagittal approach in sheep.

A reliable method of total pinealectomy in sheep without a resulting significant neurological deficit has been developed and is described. The known effect of light on sheep gonadotropin levels helps validate these studies of its pineal gland. Special attention is given to delineation of the surgical anatomy of the gland and its relationship under magnification to the central draining veins of the brain. In this large mammal this relationship differs considerably from that of humans. The application of an intrahemispheric occipital exposure using magnification, as well as the preoperative administration of steroids and osmotic agents, helped to minimize the effects of retraction and resultant cerebral edema. We have thus been able to increase the rate of successful pinealectomy to 83%, allowing the development of groups of animals suitable for studies of the neuroendocrine function of the pineal and pituitary glands.

Animals↗
PubMed1982

Experimental augmentation of cerebral blood flow by mannitol in epidural intracranial masses.

Substantial morbidity and mortality from epidural hematomas continue to be seen in major centers. In spite of great improvement in the rapidity of diagnosis, preoperative treatment and surgical techniques are relatively unchanged. Nineteen anesthetized cats were monitored before and after creation of an epidural mass. Hydrogen clearance technique was used to calculate regional cerebral blood flow (rCBF) both ipsilateral and contralateral to the mass. The control group received no other treatment and showed a decrease in rCBF to as low as 56.8% of prior flow. The experimental group received 1 gm/kg/hr of mannitol and showed augmentation of rCBF to as high as 154.9% of prior flow (p less than 0.001). The effect was seen without increase in perfusion pressure or tissue edema. This study was designed to examine the parameters of rCBF after formation of an experimental epidural mass, and shows that rCBF can be increased as part of the preoperative resuscitation of such patients.

Animals↗
PubMed1982

Perioperative management of high risk patients with cardiopulmonary disease undergoing carotid endarterectomy or extracranial-intracranial bypass.

Among a large group of patients who underwent either carotid endarterectomy or extracranial-intracranial (EC-IC) bypass were 13 patients who had cardiopulmonary monitoring performed by a dye dilution technique either with or without a thermodilution Swan-Ganz catheter. Each patient had at least two significant medical problems that were thought to place him or her at increased risk. The usefulness of this monitoring approach in the perioperative management of these patients is demonstrated by several clinical examples. No patient sustained myocardial infarction, congestive heart failure, or new neurological deficit during the perioperative period. Our experience suggests that high risk patients can safely undergo either carotid endarterectomy or EC-IC bypass provided that careful attention is paid to myocardial function and the state of hydration.

Aged↗
PubMed1982

Experimental acute hepatic encephalopathy: relationship of pathological cerebral vasodilation to increased intracranial pressure.

In clinical reports of encephalopathy and pediatric trauma, acute brain swelling has been postulated to be secondary to vasodilation of the cerebrovascular bed. Eight adult cats were studied to determine whether such pathological vasodilation was present in an experimental model of hepatic encephalopathy. All animals were anesthetized, ventilated, and monitored for intracranial pressure (ICP), arterial pressure, heart rate, arterial blood gases, temperature, and blood ammonia content. The regional cerebral blood flow (rCBF) was measured at three cortical sites by the hydrogen clearance technique. The intravenous infusion of ammonium acetate was used to produce blood ammonia levels comparable to those observed in severe Reye's syndrome. All experimental animals showed a significant increase in ICP as well as rCBF to a mean of 79.5 +/- 7.3 ml/100 g/minute. This represents a mean increase in %rCBF to 252% of control. The mean calculated cerebrovascular resistance (CVR) was noted to fall to 55 +/- 4.7% of control CVR values (p less than 0.001). This relative vasodilation was diffuse with no significant difference between hemispheres or lobes studied. Such a vasodilation, as shown by a marked fall in the resistance of the cerebrovascular bed, is a pathological response in light of the rising ICP. This suggests that pathological cerebral vasodilation may be an important cause of increased ICP in the brain suffering an acute generalized insult.

Acute Disease↗
PubMed1982

New implantable continuous administration and bolus dose intracarotid drug delivery system for the treatment of malignant gliomas.

A totally implantable system for the continuous and bolus delivery of intra-arterial chemotherapeutic agents to patients with malignant gliomas is described. The system utilizes an Infusaid pump (Infusaid Corp., Sharon, Massachusetts), which discharges the drug directly into the internal carotid artery and is percutaneously refillable. This system has been utilized experimentally in primates and in the treatment of six patients with malignant gliomas. It seems that this system can be utilized safely as an experimental technique in the treatment of malignant gliomas.

Adult↗
PubMed1981

Syringoperitoneal shunt for syringomyelia: a preliminary report.

Syringoperitoneal shunting has been used in the treatment of 4 patients with idiopathic syringomyelia. The procedures have been performed without morbidity or mortality. Postoperative observation, ranging from 7 to 23 months, has not revealed progression of symptoms or failure of the shunt. The pathophysiological theories of syringomyelia are discussed, and various surgical procedures for syringomyelia are reviewed and their results compared to the effectiveness of the syringoperitoneal shunt.

Adult↗
PubMed1981

Vertebral artery disease: radiological evaluation medical management, and microsurgical treatment.

The neuroradiological evaluation, perioperative medical management, and microsurgical treatment of variously located vertebral artery lesions are presented. Four types of surgical procedures were undertaken: proximal vertebral artery to common carotid artery end-to-side anastomosis; external carotid artery to midcervical vertebral artery end-to-side anastomosis; external carotid artery to distal cervical vertebral artery end-to-end anastomosis; and occipital artery to posterior inferior cerebellar artery end-to-side anastomosis. Each case is used to demonstrate the evaluation and management involved, the type of and rationale for the surgical procedure selected, and the patency of the anastomosis performed. Two points are emphasized. One is that, after careful angiographic evaluation and improved perioperative medical management, lesions of the vertebral artery are indeed amenable to microsurgical intervention with relatively low risk to the patient. The other is that, whenever possible, anastomosis of the largest caliber of vessels with the least number of suture lines is the surgical treatment of choice.

Carotid Arteries↗
PubMed1980

Carotid endarterectomy: technical improvements.

The immediate surgical results of 163 consecutive carotid endarterectomies performed in a neurosurgical training center are presented. The mortality rate was 0.6% and the permanent neurological morbidity rate was 2.5%. Several factors in the surgical technique including the use of magnified vision, full heparinization, the liberal use of intimal tacking sutures, and the employment of an indwelling shunt are thought to be responsible in part for the improved surgical results. (Neurosurgery, 7: 309-312, 1980).

Arterial Occlusive Diseases↗
PubMed1979

Total morbidity and mortality rates of patients with surgically treated intracranial aneurysms.

The authors report their recent experience in treating 80 patients with intracranial aneurysms. A total of 83 surgical procedures were performed with a surgical mortality of 4.8%. Fifty-six patients had suffered a subarachnoid hemorrhage. Total mortality for this group was 14.2% regardless of clinical grade. Early surgical intervention, meticulous preoperative monitoring, and control of circulatory dynamics were used to improve the perioperative morbidity and mortality rates. We believe that any major improvements in the outcome of patients with aneurysms will come from advances in perioperative management.

Brain Edema↗
PubMed1979

Gradual carotid artery occlusion in the treatment of inaccessible internal carotid artery aneurysms.

The authors discuss 21 cases of large or surgically inaccessible internal carotid artery aneurysms treated with gradual occlusion of the cervical portion of the internal carotid artery. Eighty-five per cent of the patients experienced relief or marked improvement of their symptoms after treatment. Two early cases developed postligation ischemic deficits that partially resolved. After the introduction of expansion of circulating blood volume and induced hypertension as adjuncts to graded carotid occlusion, no ischemic complications occurred.

Adult↗
PubMed1978

The relation of cerebral ischemia, hypoxia, and hypercarbia to the Cushing response.

A marked increase in intracranial pressure (ICP) produces a concomitant increase in systemic blood pressure (the Cushing response). In this study a comparison is made between this response of systemic blood pressure to increased ICP and the blood pressure responses produced by ischemia, hypoxia, and hypercarbia of the primate brain. A carotid-to-carotid cross-perfusion system was used to produce a purely cerebral hypoxia and hypercarbia. Each stimulus, except hypercarbia, produced a hypertensive response that was qualitatively and quantitatively similar. These responses were characterized by a short latent period, a rapid development, and an increase in mean arterial pressure of 60% or more. The similarity of the responses suggests that these stimuli act through a final common pathway independent of the purely mechanical effects of increased ICP upon the brain.

Animals↗
PubMed1978

Vascular dynamics of an experimental cerebral arteriovenous shunt in the primate.

An arteriovenous fistula which shunted arterial blood from the circle of Willis to the internal jugular vein was created in ten monkeys. Continued patency of the shunt was confirmed angiographically. Cerebral blood flow measurements were then obtained with the shunt both open and occluded. Flow was also determined in response to elevations of systemic arterial pressure and raised arterial carbon dioxide tensions (PaCO2), again with the shunt both patent and occluded. In addition, flow through the shunt alone was measured in response to elevations of systemic arterial pressure and PaCO2. The results suggest that flow through our arteriovenous shunt is minimally autoregulated to changes in systemic arterial pressure and is only slightly responsive to changes in PaCO2.

Animals↗