Johann Friedrich August von Esmarch--a pioneer in the field of emergency and disaster medicine.
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Emergency Medicine↗
Biomedical subjects
C W Beyer
Publications and source records attributed to C W Beyer.
Furosemide in the intraoperative reduction of intracranial pressure in the patient with subarachnoid hemorrhage.
The effect of furosemide in the intraoperative reduction of intracranial pressure was measured in 25 patients undergoing the operative repair of a ruptured intracranial aneurysm. Seven patients with similar intracranial lesions served as controls. A single bolus of 80 mg of furosemide was administered intravenously after the induction of anesthesia, and sequential measurements were made of intracranial pressure, mean arterial pressure, and arterial blood gases. A mean decrease of intracranial pressure of 56% was measured in the furosemide-treated patients, whereas the control patients demonstrated a mean decline of subarachnoid pressures of 18%. These changes are significant at the P less than 0.005 confidence level, whereas changes in mean arterial pressure, mean arterial pCO2, and base line arterial pCO2 were statistically insignificant. This study suggests that intravenous furosemide is a quick, dependable, and effective mechanism for the intraoperative reduction of intracranial pressure in the postsubarachnoid hemorrhage aneurysm patient.
Adult↗
Saphenous vein interposition grafts in the microsurgical treatment of cerebral ischemia.
Saphenous vein interposition grafts of varying lengths have been used in 25 extracranial-intracranial bypasses since 1974. Indications for operation included transient ischemic episodes (13 cases), prophylactic augmentation of middle cerebral artery (MCA) collateral flow prior to surgical treatment of intracranial aneurysm (four), and traumatic occlusion of cervical or intracranial internal carotid arteries (eight). Vein grafts to cortical branches of MCA originated from superficial temporal or occipital arteries in ten cases, common or external carotid arteries in ten, and subclavian or innominate vessels in five. Twenty-one patients have been followed up for a minimum of 12 months. Immediate patency rate was 84%; one late graft occlusion decreased overall patency to 80%. There was one operative mortality. Early technical problems, including donor-recipient size disparity, anastomotic distortion, and inappropriate graft routing, have been overcome by the use of 2-mm veins, the avoidance of hydrostatic dilation, and the construction of retroauricular tunnels. It is reasonable to assume that long-term patency of these reconstructions will parallel that of extracranial-intracranial bypasses using autologous arteries.
Arterial Occlusive Diseases↗
Intravascular use of isobutyl 2-cyanoacrylate: Part 1 Treatment of intracranial arteriovenous malformations.
The intravascular use of the rapidly polymerizing acrylic compound, isobutyl 2-cyanoacrylate (IBC), in 10 patients with intracranial arteriovenous malformations (AVMs) is described. The monomer was introduced into each malformation at craniotomy using angiographic control and microvascular dissection technique to identify, isolate, and inject the major components of each vascular lesion while attempting to preserve normal arterial circulation. Postoperative angiography was used routinely to evaluate the results of IBC embolization. Four patients underwent the injection and immediate surgical excision of an intracranial AVM, and 6 underwent injection alone; 3 of the latter had residual malformation demonstrated on postoperative angiography, and 1 of these patients had the remnants of her malformation occluded by a second embolic procedure. There was no operative mortality nor permanent neurological morbidity. Three patients suffered transient neurological dysfunction in the immediate postoperative period.
Adult↗
Intravascular use of isobutyl 2-cyanoacrylate: Part 2 Treatment of carotid-cavernous fistulas.
The intravascular use of the rapidly polymerizing acrylic compound isobutyl 2-cyanoacrylate in four patients with carotid-cavernous fistulas is described. The monomer was injected into the cavernous sinus at craniotomy after the intraoperative angiographic identification of the fistula site and the origin of its venous drainage. All patients had postoperative angiographic documentation of fistula closure and confirmed carotid artery patency. There was no operative mortality or permanent neurological morbidity. Two patients (50%) suffered transient dysfunction in the immediate postoperative period of one of the cranial nerves that transit the cavernous sinus.
Adult↗
Significance of the so-called absorptive reserve in communicating hydrocephalus: a preliminary report.
Twelve patients with communicating hydrocephalus were studied with a servocontrolled lumbar infusion technique to measure net cerebrospinal fluid (CSF) absorptive capacity and resting pressure. Each patient showed a significant absorptive reserve; the rate of CSF absorption exceeded the rate of formation over a physiological range of pressure. The size of the ventricles did not correlate with either the absorptive capacity or the resting pressure parameter, or both. The data suggest that communicating hydrocephalus does not reflect a simple imbalance between the rates of CSF formation and absorption. Other factors must be of etiological importance and are considered in the discussion.
Absorption↗
Osmotic blood-brain barrier disruption: pharmacodynamic studies in dogs and a clinical phase I trial in patients with malignant brain tumors.
Infusion of 25% mannitol in saline into the internal carotid artery of dogs disrupts the blood-brain barrier (BBB) in a controlled and reproducible manner (osmotic disruption), whereas mannitol infused through the common carotid artery produces variable disruption of the BBB. Compared to controls, infusion of methotrexate in dogs after osmotic disruption produced significantly higher drug levels in brain. We report very preliminary data on the effects of osmotic disruption with mannitol in five patients harboring malignant brain tumors.
Animals↗
Servo-controlled lumbar infusions in children. A quantitative approach to the problem of arrested hydrocephalus.
Servo-controlled variable-rate lumbar infusions were performed in 11 children with presumed cerebrospinal fluid (CSF) absorptive defects. The CSF dynamics were determined as a function of intracranial pressure in terms of CSF absorptive capacity and resting pressure. These physiological measurements showed poor correlation with traditional clinical signs. On the basis of the CSF measurements there were four children with arrested hydrocephalus, one with compensated hydrocephalus, three with active hydrocephalus, and three with brain atrophy. Retrospective management decisions based on the clinical presentations, physical findings, and traditional diagnostic tests disagreed with management as indicated by the CSF measurements in eight of 11 cases. It is suggested that this technique may be a useful diagnostic tool for difficult clinical problems.
Atrophy↗
Physiological features of the pressure-volume function of brain elasticity in man.
The intracranial pressure-volume relationship of brain elasticity was examined in 20 patients with suspected disorders of the cerebrospinal fluid (CSF) system. Elasticity measurements were made as the patients were studied with a servo-controlled lumbar infusion technique to measure CSF absorptive capacity. The data were evaluated to determine the relationship between intracranial pressure (ICP) and volume, and between ICP variability and the level of ICP. The results confirm the exponential nature of the pressure-volume elasticity function in patients who are not critically ill. Eight of the 20 patients were shown to have normal CSF absorptive capacities, and there was no difference between their elasticity measurements and those of patients with absorptive defects. In addition, ICP variability was shown to be linearly related to the actual level of ICP. The physiological features of the pressure-volume elasticity function are reviewed. Based on these considerations, the clinical value and significance of elasticity measurements is questioned.
Adolescent↗
Brain elasticity changes with ventriculomegaly.
The pressure-volume relationship of brain elasticity was determined in 32 patients during servo-controlled variable-rate lumbar infusions to measure net cerebrospinal fluid (CSF) absorptive capacity. Several indices were used to estimate ventricular size from computerized tomography scans. The results show a linear relationship between ventricular size and the elasticity slope which relates the natural logarithm of pressure to volume. It follows that a hydrocephalic patient should show a greater intracranial pulse amplitude at a given pressure than does a patient with normal-sized ventricles. Although these elasticity changes may simply be the result of the ventriculomegaly, it seems possible that the pressure-volume elasticity relationship may be of etiological importance in disorders of the CSF system.
Adolescent↗
Failure of extracranial-intracranial arterial bypass in acute middle cerebral artery occlusion: case report.
Extracranial-intracranial arterial bypass procedures provide important augmentation of collateral circulation to cortical areas rendered potentially ischemic by therapeutic occlusion of major branches of the circle of Willis. Although the case studies reported to date in general reflect positively on this use of the bypass procedure, this report of a patient who failed to tolerate acute middle cerebral artery occlusion despite the presence of a patent superficial temporal-middle cerebral artery branch anastomosis points up several of the practical and theoretical limitations of this therapeutic approach. Certain modifications of the timing of the bypass procedure, the selection of donor and recipient arteries, and the mechanics of intracranial arterial occlusion may allow a wider application of extracranial-intracranial arterial bypass in this therapeutic setting.
Acute Disease↗
Traumatic middle cerebral artery aneurysm: case report.
A case of traumatic middle cerebral artery aneurysm is presented. The case demonstrates some of the difficulties encountered when dealing with this type of aneurysm. The unusual surgical approach required for obliteration is described.
Adult↗
Cerebrospinal fluid dynamics in patients with pseudotumor cerebri.
CSF dynamics were determined as a function of intracranial pressure in patients with pseudotumor cerebri. Servocontrolled variable rate lumbar infusions were used to determine net CSF-absorptive capacities and resting pressures in 10 patients; serial studies were done in 5 of the patients. Nearly all of the patients had abnormally low CSF-absorptive capacities. On the other hand, marked elevations in resting pressure were not a constant feature of the disease. Concurrent changes in the cerebrovascular bed could introduce errors into this manometric determination of CSF dynamics; the significance of this potential artifact is examined. The results of this study suggest that the CSF compartment may be of etiological importance in the pathophysiology of pseudotumor cerebri.
Adolescent↗
Risk of intracranial aneurysm surgery in the good grade patient: early versus late operation.
To evaluate the risk of definitive intracranial microsurgical aneurysm obliteration as a function of the timing of the operative intervention, we retrospectively reviewed 106 consecutive patients in good clinical condition who underwent such surgery. The patients who were operated upon within the first 8 days of their most recent subarachnoid hemorrhage formed the "early" group; the patients operated upon between the 9th and 31st day were considered to have undergone "late" surgery. On the basis of their clinical outcome the patients were allocated to one of four outcome categories ("good," "fair," "death") both at the time of their hospital discharge and at their most recent clinical re-evaluation, a minimum of 6 months after discharge from the hospital. There was no significant difference in the operative mortality in each group (early surgery, 5%; late surgery, 4%); additionally, no significant difference was noted in the incidence of either intraoperative complications or postoperative morbidity. A suggestive but statistically insignificant increase in the incidence of postoperative cerebral ischemic events was seen in the "early" surgery group (8% vs. 4% for the "late" surgery group). The potential significance of these findings for the timing of intracranial aneurysm surgery is discussed.
Brain Ischemia↗
Osmotic blood-brain barrier disruption: a new means of increasing chemotherapeutic agent delivery.
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Animals↗
More on interpretation of pH data.
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Gastric Juice↗
Servo-controlled lumbar infusions: a clinical tool for the determination of CSF dynamics as a function of pressure.
The variable rate lumbar subarachnoid infusion technique allows rapid quantitative study of the cerebrospinal fluid (CSF) compartment. Numerous pressure plateaus are studied in a brief time period with a servo-controlled system. The test determines the difference between rates of CSF absorption and formation as a function of pressure. On-line computer data analysis increases experimental efficiency to guarantee statistical significance. Animal and patient data are presented in the report.
Absorption↗