Cerebral Critical Closing Pressure During Infusion Tests

2016 ◽  
pp. 215-220 ◽  
Author(s):  
Georgios V. Varsos ◽  
Marek Czosnyka ◽  
Peter Smielewski ◽  
Matthew R. Garnett ◽  
Xiuyun Liu ◽  
...  
Keyword(s):  
Critical Closing Pressure ◽  
Closing Pressure

A square-pulse flow method for measuring characteristics of the arterial bed

1976 ◽  
Vol 40 (3) ◽  
pp. 425-433 ◽  
Author(s):  
M. G. Bottomley ◽  
G. W. Mainwood
Keyword(s):  
Arterial Compliance ◽  
Peripheral Resistance ◽  
Mean Value ◽  
Pressure Response ◽  
Arterial System ◽  
Response Curves ◽  
Arterial Tree ◽  
Pulse Flow ◽  
Critical Closing Pressure ◽  
Closing Pressure

A device was designed to provide a “square” pulse of blood flow into the arterial system. Pulses were injected into the carotid artery of the rabbit during transient cardiac arrest. Analysis of pressure response curves generated by the flow provides information as to the state of the arterial tree. With certain assumptions it is possible to estimate from these curves lumped values of peripheral resistance, critical closing pressure, and arterial compliance. In a series of 12 rabbits the mean value of peripheral resistance was found to be 0.21 +/- 0.7 mmHg-ml-1-min and critical closing pressure was estimated to be 23.6 +/- 3.8 mmHg. This method gives two possible values for arterial compliance 0.036 +/- 0.010 and 0.055 +/- 0.010 ml-mm-1 based, respectively, on the rise and decay curves of the pressure response. The theory and limitations of the method are discussed. The use of the method is illustrated in following the response to increased PCO2 and hemorrhage.

Critical Closing Pressure During a Controlled Increase in Intracranial Pressure

2018 ◽  
pp. 133-137
Author(s):  
Katarzyna Kaczmarska ◽  
Magdalena Kasprowicz ◽  
Antoni Grzanka ◽  
Wojciech Zabołotny ◽  
Peter Smielewski ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Critical Closing Pressure ◽  
Closing Pressure

Asystolic Gradient, Intrinsic Blood Pressure and Critical Closing Pressure in the Human Forearm

1956 ◽  
Vol 9 (1) ◽  
pp. 69-74 ◽  
Author(s):  
A. Lanari ◽  
B. Bromberger-Barnea ◽  
E. Attinger
Keyword(s):  
Blood Pressure ◽  
Critical Closing Pressure ◽  
Human Forearm ◽  
Closing Pressure

Abolition of autoregulation of renal blood flow by acetylcholine

1964 ◽  
Vol 207 (1) ◽  
pp. 123-127 ◽  
Author(s):  
Victor E. Nahmod ◽  
Alfredo Lanari
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Run Off ◽  
Critical Closing Pressure ◽  
Flow Pressure ◽  
Renal Blood Flow Autoregulation ◽  
Autoregulatory Mechanism ◽  
Closing Pressure

In order to study the mechanism of autoregulation of renal blood flow, 36 mongrel dogs were connected in parabiosis according to the Brull method. The following determinations were made: a) flow/pressure curves in innervated and denervated kidneys and b) acetylcholine and arterenol infusion in innervated kidneys. The critical closing pressure and the "run-off" index were also determined in all cases. The results of these experiments show the existence of renal blood flow autoregulation in innervated, denervated, and arterenol-infused kidneys, and the abolition of the autoregulatory mechanism in the acetylcholine-infused kidneys. The run-off index showed a better correlation with renal resistance than with critical closing pressure.

scholarly journals The critical closing pressure contribution to dynamic cerebral autoregulation in humans: influence of arterial partial pressure of CO 2

2020 ◽  
Vol 598 (24) ◽  
pp. 5673-5685
Author(s):  
Ronney B. Panerai ◽  
Jatinder S. Minhas ◽  
Osian Llwyd ◽  
Angela S. M. Salinet ◽  
Emmanuel Katsogridakis ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Cerebral Autoregulation ◽  
Arterial Partial Pressure ◽  
Critical Closing Pressure ◽  
Closing Pressure ◽  
Dynamic Cerebral Autoregulation

Immediate responses of collateral vessels to abrupt arterial occlusion

1964 ◽  
Vol 206 (6) ◽  
pp. 1299-1303 ◽  
Author(s):  
Albert J. Roy ◽  
Peter B. Lambert ◽  
Howard A. Frank
Keyword(s):  
Arterial Occlusion ◽  
Cheek Pouch ◽  
Large Artery ◽  
Opening Pressure ◽  
Hamster Cheek Pouch ◽  
Arterial Ligation ◽  
Critical Closing Pressure ◽  
Collateral Vessels ◽  
Closing Pressure

The vascular bed of the hamster cheek pouch was observed in vivo under the microscope as a major artery within the field was occluded. Two changes were noted: 1) an alteration in pattern of blood flow and 2) the opening of previously unseen branches on each side of the ligature. Both responses were immediate and persisting. Besides providing for new flow patterns, the newly opened arterial branches preserve additional length of the ligated artery which becomes obliterated on each side of the ligature to the nearest open branch. Comparison of in vivo with postmortem observations indicated that latent and open branches of the artery under observation were about equal in number, and that about half of the latent branches opened in response to the ligation. Induced vasoconstriction delayed the opening of latent branches, cold prevented it. Priscoline opened all latent vessels, with or without arterial ligation. In connection with Burton's data on "critical closing pressure" of fine vessels, the ligation of a large artery appears to establish a "critical opening pressure" within latent branches.

Tissue pressure and critical closing pressure in the isolated denervated dog foreleg

1959 ◽  
Vol 196 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Lerner B. Hinshaw ◽  
Stacey B. Day
Keyword(s):  
Pressure Difference ◽  
Null Point ◽  
Homologous Blood ◽  
Venous Outflow ◽  
Tissue Pressure ◽  
Tissue Edema ◽  
Critical Closing Pressure ◽  
Arterial Inflow ◽  
Low Pressures ◽  
Closing Pressure

Experiments designed to obtain very low pressures and flows in the isolated leg were performed on the weighed, denervated dog foreleg perfused with homologous blood. Continuous strain gauge recordings of pressure decay curves and rates of weight loss (venous outflow) were obtained after arrest of the arterial inflow. In some instances tissue pressures were measured by a ‘null-point’ procedure. The results provide no evidence for a generalized critical closing pressure in the denervated, blood-perfused, nonedematous leg. After occlusion of arterial inflow the arteriovenous pressure difference fell to zero (0.0 mm Hg) as venous outflow approached zero. Evidence was obtained showing that if a pressure difference is found at zero flow in the isolated leg, it is produced by the existing tissue pressure. An elevated closing pressure is readily obtained in the dog foreleg when the tissue pressure is increased, and its magnitude is directly related to the extent of tissue edema.

Cortical artery pressure in normotensive and hypertensive aneurysm patients

1983 ◽  
Vol 59 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Jack M. Fein ◽  
Kenneth Lipow ◽  
Anthony Marmarou
Keyword(s):  
Anterior Circulation ◽  
Hypertensive Patients ◽  
Content Type ◽  
Artery Pressure ◽  
Systemic Pressure ◽  
Relative Contribution ◽  
Critical Closing Pressure ◽  
The Relationship ◽  
Best Fit ◽  
Closing Pressure

✓ Cortical artery pressure (CAP) and systemic pressure (SP) were measured in eight normotensive and six hypertensive patients with anterior circulation aneurysms. In the hypertensive patients significant gradients developed between CAP and SP as these pressures were lowered. The relationship between CAP and SP was expressed by the best-fit equation CAP = 1.02 SP − 9.27 in the normotensive patients and by CAP = 1.54 SP − 65.60 in the hypertensive patients. In the latter, the cycle of decreasing and increasing pressures formed a hysteresis loop suggesting prolonged cortical vasoconstriction despite recovery of systemic pressure. Selective pressure measurements in the distal (D) and proximal (P) segments of the cortical arteries were also obtained. The D/P ratio describes the relative contribution of the collateral circulation to cortical artery pressure. In normotensive patients, the D/P ratio was maintained down to an SP of 48 mm Hg. In hypertensive patients this ratio decreased with lowered SP, and a critical closing pressure of 40 mm Hg was predicted for the distal circulation. These studies describe the limited capacity of the cortical circulation to maintain perfusion pressure in hypertensive patients. These responses should be considered when assessing the risks associated with such procedures as carotid ligation or hypotensive anesthesia.

HEMODILUTION DECREASES CRITICAL CLOSING PRESSURE BUT DOES NOT INCREASE THE AORTIC TO DISTAL PRESSURE GRADIENT IN DOGS

1998 ◽  
Vol 86 (Supplement) ◽  
pp. 66SCA
Author(s):  
J Urzua ◽  
G Nunez ◽  
G Meneses ◽  
G Lema ◽  
R Canessa ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Critical Closing Pressure ◽  
Closing Pressure
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