Relationship of perfusion pressure and size to risk of hemorrhage from arteriovenous malformations

1992 ◽  
Vol 76 (6) ◽  
pp. 918-923 ◽  
Author(s):  
Robert F. Spetzler ◽  
Ronald W. Hargraves ◽  
Patrick W. McCormick ◽  
Joseph M. Zabramski ◽  
Richard A. Flom ◽  
...  
Keyword(s):  
Perfusion Pressure ◽  
Feeding Artery ◽  
Content Type ◽  
Arterial Blood ◽  
The Mean ◽  
Feeding Pressure ◽  
Risk Of Hemorrhage ◽  
Relationship Of ◽  
The Relationship ◽  
Fine Print

✓ The relationship between the size of an arteriovenous malformation (AVM) and its propensity to hemorrhage is unclear. Although nidus volume increases geometrically with respect to AVM diameter, hemorrhages are at least as common, in small AVM's compared to large AVM's. The authors prospectively evaluated 92 AVM's for nidus size, hematoma size, and arterial feeding pressure to determine if these variables influence the tendency to hemorrhage. Small AVM's (diameter ≤ 3 cm) presented with hemorrhage significantly more often (p < 0.001) than large AVM's (diameter > 6 cm), the incidence being 82% versus 21%. Intraoperative arterial pressures were recorded from the main feeding vessel(s) in 24 of the 92 patients in this series: 10 presented with hemorrhage and 14 presented with other neurological symptoms. In the AVM's that had hemorrhaged, the mean difference between mean arterial blood pressure and the feeding artery pressure was 6.5 mm Hg (range 2 to 15 mm Hg). In the AVM's that did not rupture, this difference was 40 mm Hg (range 17 to 63 mm Hg). Smaller AVM's had significantly higher feeding artery pressures (p < 0.05) than did larger AVM's, and they were associated with large hemorrhages. It is suggested that differences in arterial feeding pressure may be responsible for the observed relationship between the size of AVM's and the frequency and severity of hemorrhage.

Cerebral autoregulation following head injury

2001 ◽  
Vol 95 (5) ◽  
pp. 756-763 ◽  
Author(s):  
Marek Czosnyka ◽  
Piotr Smielewski ◽  
Stefan Piechnik ◽  
Luzius A. Steiner ◽  
John D. Pickard
Keyword(s):  
Head Injury ◽  
Cerebral Autoregulation ◽  
Perfusion Pressure ◽  
Content Type ◽  
Arterial Blood ◽  
Head Injured ◽  
The Mean ◽  
Injured Patients ◽  
The Relationship ◽  
Fine Print

Object. The goal of this study was to examine the relationship between cerebral autoregulation, intracranial pressure (ICP), arterial blood pressure (ABP), and cerebral perfusion pressure (CPP) after head injury by using transcranial Doppler (TCD) ultrasonography. Methods. Using ICP monitoring and TCD ultrasonography, the authors previously investigated whether the response of flow velocity (FV) in the middle cerebral artery to spontaneous variations in ABP or CPP provides reliable information about cerebral autoregulatory reserve. In the present study, this method was validated in 187 head-injured patients who were sedated and receiving mechanical ventilation. Waveforms of ICP, ABP, and FV were recorded over intervals lasting 20 to 120 minutes. Time-averaged mean FV and CPP were determined. The correlation coefficient index between FV and CPP (the mean index of autoregulation [Mx]) was calculated over 4-minute epochs and averaged for each investigation. The distribution of averaged mean FV values converged with the shape of the autoregulatory curve, indicating lower (CPP < 55 mm Hg) and upper (CPP > 105 mm Hg) thresholds of autoregulation. The relationship between the Mx and either the CPP or ABP was depicted as a U-shaped curve. Autoregulation was disturbed in the presence of intracranial hypertension (ICP ≥ 25 mm Hg) and when mean ABP was too low (ABP < 75 mm Hg) or too high (ABP > 125 mm Hg). Disturbed autoregulation (p < 0.005) and higher ICP (p < 0.005) occurred more often in patients with unfavorable outcomes than in those with favorable outcomes. Conclusions. Autoregulation not only is impaired when associated with a high ICP or low ABP, but it can also be disturbed by too high a CPP. The Mx can be used to guide intensive care therapy when CPP-oriented protocols are used.

The effects of mass-induced intracranial pressures on arterial hypertension and survival in awake cats

1972 ◽  
Vol 37 (5) ◽  
pp. 514-527 ◽  
Author(s):  
Stanley J. Goodman ◽  
Donald P. Becker ◽  
John Seelig
Keyword(s):  
Intracranial Pressure ◽  
Systemic Hypertension ◽  
Content Type ◽  
Arterial Blood ◽  
Mass Size ◽  
Intracranial Pressures ◽  
Relationship Of ◽  
The Relationship ◽  
Awake Cats ◽  
Supratentorial Mass

✓ Intracranial pressures above and below the tentorium, arterial blood pressure, heart rate, and respiratory rate were recorded continuously before, during, and after expansion of a supratentorial mass in awake unsedated cats. In general, as the mass enlarged, the intracranial pressure rose; however, considerable variation was observed among animals with respect to specific mass size and associated intracranial pressures. There was considerable variation in the relationship of supratentorial pressure to infratentorial pressure. No animal survived that had sustained a mass-induced pressure exceeding 1100 mm H2O, and survival was shorter with greater pressures. Systemic hypertension occurred always and only when the infratentorial pressure exceeded 600 mm H2O, regardless of the magnitude of the associated supratentorial intracranial pressure. The methodological limitations of previous studies of mass-induced intracranial hypertension appear to have been substantially reduced by the technique described.

Evaluation of a method for noninvasive intracranial pressure assessment during infusion studies in patients with hydrocephalus

2000 ◽  
Vol 92 (5) ◽  
pp. 793-800 ◽  
Author(s):  
Bernhard Schmidt ◽  
Marek Czosnyka ◽  
Jens Jürgen Schwarze ◽  
Dirk Sander ◽  
Werner Gerstner ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Intracranial Pressure ◽  
Time Course ◽  
Cerebral Blood Flow Velocity ◽  
Absolute Error ◽  
Content Type ◽  
Arterial Blood ◽  
Potential Clinical Benefit ◽  
The Mean ◽  
Fine Print

Object. A mathematical model previously introduced by the authors allowed noninvasive intracranial pressure (nICP) assessment. In the present study the authors investigated this model as an aid in predicting the time course of raised ICP during infusion tests in patients with hydrocephalus and its suitability for estimating the resistance to outflow of cerebrospinal fluid (Rcsf).Methods. Twenty-one patients with hydrocephalus were studied. The nICP was calculated from the arterial blood pressure (ABP) waveform by using a linear signal transformation, which was dynamically modified by the relationship between ABP and cerebral blood flow velocity. This model was verified by comparison of nICP with “real” ICP measured during lumbar infusion tests. In all simulations, parallel increases in real ICP and nICP were evident. The simulated Rcsf was computed using nICP and then compared with Rcsf computed from real ICP. The mean absolute error between real and simulated Rcsf was 4.1 ± 2.2 mm Hg minute/ml. By the construction of simulations specific to different subtypes of hydrocephalus arising from various causes, the mean error decreased to 2.7 ± 1.7 mm Hg minute/ml, whereas the correlation between real and simulated Rcsf increased from R = 0.73 to R = 0.89 (p < 0.001).Conclusions. The validity of the mathematical model was confirmed in this study. The creation of type-specific simulations resulted in substantial improvements in the accuracy of ICP assessment. Improvement strategies could be important because of a potential clinical benefit from this method.

A simple, inexpensive technique for accurate mass localization by computerized tomography

1980 ◽  
Vol 52 (5) ◽  
pp. 733-735 ◽  
Author(s):  
John I. Moseley ◽  
Steven L. Giannotta ◽  
Justin W. Renaudin
Keyword(s):  
Computerized Tomography ◽  
Accurate Mass ◽  
Content Type ◽  
Accurate Localization ◽  
Relationship Of ◽  
The Relationship ◽  
Inexpensive Technique ◽  
Tomography Scanning ◽  
Fine Print

✓ A simple wire template is placed on the patient's head during computerized tomography scanning, and the results of the scan are later reproduced on the scalp prior to surgery. Measurements of the distance between the wires and the relationship of the mass provide the key to accurate localization of the mass on the scalp surface.

Laboratory experience with a magnetically guided intravascular catheter system

1973 ◽  
Vol 38 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Herbert L. Cares ◽  
J. Richard Hale ◽  
D. Bruce Montgomery ◽  
Howard A. Richter ◽  
William H. Sweet
Keyword(s):  
Intravascular Catheter ◽  
Selective Angiography ◽  
Content Type ◽  
Laboratory Experience ◽  
Arteriovenous Fistulas ◽  
Catheter System ◽  
Relationship Of ◽  
The Relationship ◽  
Fine Print

✓ An improved magnetically-guided intravascular catheter system in dogs is described as safe, requiring little attention, allowing the application of flow surges to aid propulsion of the tip, and providing for angiography of good quality. Current concepts of the relationship of magnetic and flow guidance are discussed. The uses of the system demonstrated include selective angiography, perfusion of isobutyl-2-cyanoacrylate into experimental arteriovenous fistulas, and perfusion of microparticulate iron suspensions into experimental aneurysms. A unique detachable macroballoon that may function as a reversible tethered embolus is reported.

Immunobiology of primary intracranial tumors

1977 ◽  
Vol 47 (6) ◽  
pp. 871-885 ◽  
Author(s):  
Ronald E. Woosley ◽  
M. Stephen Mahaley ◽  
Jane L. Mahaley ◽  
Gary M. Miller ◽  
William H. Brooks
Keyword(s):  
Effector Cell ◽  
Intracranial Tumors ◽  
Content Type ◽  
Postoperative Course ◽  
Immune Parameters ◽  
Relationship Of ◽  
The Relationship ◽  
Cytotoxic Responses ◽  
Fine Print

✓ Fifty-six in vitro microcytotoxicity assays were conducted on 30 patients with intracranial tumors at various times during their postoperative course. Significant specific cellular cytotoxic responses were found in nine of 56 assays, humoral cytotoxic responses in nine of 54 assays, and host effector cell-dependent, antibody-dependent cytotoxic responses in four of 28 assays. Variables that might influence the occurrence of cytotoxicity were studied, and the relationship of these findings to other immune parameters was discussed.

No ordinary time, no ordinary men: the relationship between Harvey Cushing and Franklin D. Roosevelt, 1928–1939

2001 ◽  
Vol 95 (2) ◽  
pp. 354-368 ◽  
Author(s):  
Richard L. Rovit ◽  
William T. Couldwell
Keyword(s):  
Personal Relationship ◽  
Content Type ◽  
Harvey Cushing ◽  
Medical Issues ◽  
Ordinary Time ◽  
The Times ◽  
Franklin Delano Roosevelt ◽  
Relationship Of ◽  
The Relationship ◽  
Fine Print

✓ The authors elucidate the strong personal relationship that developed between Dr. Harvey Cushing and Franklin Delano Roosevelt (FDR) from 1928 to 1939, as manifested in their frequent letters to each other. The relationship was initiated by the marriage of their children. Through his correspondence with FDR, Cushing was able to affect several medical issues of the period. The relationship of these two individuals is set within the historical, social, and political contexts of the times.

Relation of preoperative angiographic characteristics of the posterior communicating artery to the results of common carotid ligation

1972 ◽  
Vol 36 (5) ◽  
pp. 564-568 ◽  
Author(s):  
Kenneth Tuerk ◽  
Norman E. Chase ◽  
Irvin I. Kricheff ◽  
Joseph P. Lin ◽  
Joseph Ransohoff
Keyword(s):  
Contrast Material ◽  
Posterior Communicating Artery ◽  
Carotid Angiography ◽  
Content Type ◽  
Carotid Ligation ◽  
Before And After ◽  
Relationship Of ◽  
The Relationship ◽  
Fine Print

✓ Twenty patients with posterior communicating artery aneurysms were treated with common carotid ligation. Postligation visualization was accomplished in 16 cases by ipsilateral brachial angiography. Two other aneurysms were visualized by contralateral brachial and contralaterial carotid angiography. The size of the aneurysm was measured before and after ligation. The relationship of postoperative reduction in size to preoperative angiographic characteristics was studied. Reduction in the size of the aneurysm occurred most often when preoperative angiography showed that the sac was long and its neck narrow, and when there was stasis of contrast material in the aneurysm.

Thrombosis: the relationship of hemostatic mechanisms to drug therapy

1981 ◽  
Vol 54 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Stanford Wessler ◽  
Sanford N. Gitel
Keyword(s):  
Drug Therapy ◽  
Content Type ◽  
Relationship Of ◽  
The Relationship ◽  
Fine Print

✓ The mechanisms of arteriovenous and microcirculatory thrombosis and embolism are presented. Drugs affecting the hemostatic balance and their specific actions and indications are reviewed.

Meningomyelocele and progressive hydromyelia

1975 ◽  
Vol 43 (4) ◽  
pp. 457-463 ◽  
Author(s):  
Peter V. Hall ◽  
Robert L. Campbell ◽  
John E. Kalsbeck
Keyword(s):  
Clinical Improvement ◽  
Sensory Loss ◽  
Ventricular Drainage ◽  
Prominent Feature ◽  
Content Type ◽  
Relationship Of ◽  
The Relationship ◽  
Progressive Paraparesis ◽  
Fine Print

✓ Five cases of myelodysplasia with progressive paraparesis are presented. Three of the five patients developed spasticity, but dissociated sensory loss and loss of sphincter control was not a prominent feature. All were found to have compensated hydrocephalus and extensive communicating hydromyelia. The use of myelography and ventriculography in the diagnosis of hydromyelia is discussed. Ventricular drainage led to clinical improvement in two cases and radiological improvement in one. The relationship of compensated hydrocephalus, meningomyelocele, and progressive hydromyelia postnatally may support the hydrodynamic hypothesis of myelodysplasia.

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