scholarly journals INTERACTION IN SHEEP BETWEEN MEAN ARTERIAL PRESSURE AND CROSS–SECTIONAL AREA OF THE DESCENDING AORTA

1987 ◽  
Vol 67 (3) ◽  
pp. A178-A178 ◽  
Author(s):  
W. List ◽  
N. Gravenstein ◽  
T. Banner ◽  
D. Caton ◽  
R. F. Davis
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Descending Aorta

scholarly journals The Effect of PEEP on Cross Sectional Area of Right Internal Jugular Vein in Anaesthetised Patients Using Ultrasonography - An Observational Study

2020 ◽  
Vol 7 (44) ◽  
pp. 2530-2533
Author(s):  
Praseetha V.K. ◽  
Sunil R
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Observational Study ◽  
Arterial Pressure ◽  
Internal Jugular Vein ◽  
Jugular Vein ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Government

BACKGROUND Central Venous Cannulation is a very important technique needed intra operatively and in critical care setting. Most commonly accessed is the right internal jugular vein due to lesser incidence of complications and easy accessibility. Ultrasound guidance improves the successful insertion rate than blind technique. Increasing the cross-sectional area (CSA) of IJV improves the success rate and decreases complications. Several manoeuvres such as Trendelenburg’s position, Valsalva’s manoeuvre, hepatic compression and positive end-expiratory pressure have been used to increase the diameter of the IJV. Application of PEEP of 10–12 cm H2O in supine position has been found to increase the CSA of right IJV in various studies. The aim of the study is to determine the optimal PEEP which increases size of IJV without complications. METHODS This is an observational study conducted in the Government Medical College, Thrissur. The groups were chosen from instances where three different levels of PEEP were used. A total of 90 ASA PS 1 & 2 patients who received general anaesthesia for elective surgeries where assigned to three groups - P0, P5 and P10 with different values of PEEP- 0, 5, and 10 cm of H2O respectively. Patients with obesity, raised intracranial pressure, previous neck surgery were excluded from the study. After application of PEEP for 2 minutes, the diameter of Right Internal Jugular was sonologically measured. The increase in cross sectional area of IJV in each group was analysed. Application of PEEP affects heart rate and mean arterial pressure in patients. So, the heart rate and mean arterial pressure readings were taken at the time of measurement of IJV. These were also analysed statistically. RESULTS The three groups P0, P5 and P10 were comparable in demographic parameters like age and weight. Cross-sectional area of three groups was compared. The mean CSA in P0 was 1.3345, P5 was 1.399 and P10 was 1.443 cm2. (p .001). There was a statistically significant increase in cross-sectional area of IJV when PEEP was applied. Increase in CSA was significantly higher with higher PEEP (p .001). CONCLUSIONS The application of PEEP of 5 to 10 cm of H2O is a safe method to increase the area of IJV for successful cannulation. This value of PEEP did not cause clinically significant haemodynamic effects. KEYWORDS PEEP, Cross-Sectional Area of IJV, Sonoanatomy, IJV Cannulation

A computed method for noninvasive MRI assessment of pulmonary arterial hypertension

2004 ◽  
Vol 96 (2) ◽  
pp. 463-468 ◽  
Author(s):  
Eric Laffon ◽  
Christophe Vallet ◽  
Virginie Bernard ◽  
Michel Montaudon ◽  
Dominique Ducassou ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Cross Sectional Area ◽  
Physical Parameters ◽  
Sectional Area ◽  
Biophysical Parameters ◽  
Cross Sectional ◽  
Mean Pulmonary Arterial Pressure ◽  
Pulmonary Arterial ◽  
The Mean

The present method enables the noninvasive assessment of mean pulmonary arterial pressure from magnetic resonance phase mapping by computing both physical and biophysical parameters. The physical parameters include the mean blood flow velocity over the cross-sectional area of the main pulmonary artery (MPA) at the systolic peak and the maximal systolic MPA cross-sectional area value, whereas the biophysical parameters are related to each patient, such as height, weight, and heart rate. These parameters have been measured in a series of 31 patients undergoing right-side heart catheterization, and the computed mean pulmonary arterial pressure value (PpaComp) has been compared with the mean pressure value obtained from catheterization (PpaCat) in each patient. A significant correlation was found that did not differ from the identity line PpaComp = PpaCat ( r = 0.92). The mean and maximal absolute differences between PpaComp and PpaCat were 5.4 and 11.9 mmHg, respectively. The method was also applied to compute the MPA systolic and diastolic pressures in the same patient series. We conclude that this computed method, which combines physical (whoever the patient) and biophysical parameters (related to each patient), improves the accuracy of MRI to noninvasively estimate pulmonary arterial pressures.

Valsalva's maneuver revisited: a quantitative method yielding insights into human autonomic control

1996 ◽  
Vol 271 (3) ◽  
pp. H1240-H1249 ◽  
Author(s):  
M. L. Smith ◽  
L. A. Beightol ◽  
J. M. Fritsch-Yelle ◽  
K. A. Ellenbogen ◽  
T. R. Porter ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Cross Sectional Area ◽  
Neuronal Firing ◽  
Right Atrial ◽  
Sectional Area ◽  
Nerve Activity ◽  
Cross Sectional ◽  
Muscle Nerve ◽  
Peripheral Arterial ◽  
Valsalva’S Maneuver

Seventeen healthy supine subjects performed graded Valsalva maneuvers. In four subjects, transesophageal echographic aortic cross-sectional areas decreased during and increased after straining. During the first seconds of straining, when aortic cross-sectional area was declining and peripheral arterial pressure was rising, peroneal sympathetic muscle neurons were nearly silent. Then, as aortic cross-sectional area and peripheral pressure both declined, sympathetic muscle nerve activity increased, in proportion to the intensity of straining. Poststraining arterial pressure elevations were proportional to preceding increases of sympathetic activity. Sympathetic inhibition after straining persisted much longer than arterial and right atrial pressure elevations. Similarly, R-R intervals changed in parallel with peripheral arterial pressure, until approximately 45 s after the onset of straining, when R-R intervals were greater and arterial pressures were smaller than prestraining levels. Our conclusions are as follows: opposing changes of carotid and aortic baroreceptor inputs reduce sympathetic muscle and increase vagal cardiac motor neuronal firing; parallel changes of barorsensory inputs provoke reciprocal changes of sympathetic and direct changes of vagal firing; and pressure transients lasting only seconds reset arterial pressure-sympathetic and -vagal response relations.

Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe

2009 ◽  
Vol 297 (4) ◽  
pp. R1058-R1065 ◽  
Author(s):  
E. Brøndum ◽  
J. M. Hasenkam ◽  
N. H. Secher ◽  
M. F. Bertelsen ◽  
C. Grøndahl ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Venous Pressure ◽  
Upright Position ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Jugular Veins ◽  
Cross Sectional ◽  
Spontaneously Breathing

How blood flow and pressure to the giraffe's brain are regulated when drinking remains debated. We measured simultaneous blood flow, pressure, and cross-sectional area in the carotid artery and jugular vein of five anesthetized and spontaneously breathing giraffes. The giraffes were suspended in the upright position so that we could lower the head. In the upright position, mean arterial pressure (MAP) was 193 ± 11 mmHg (mean ± SE), carotid flow was 0.7 ± 0.2 l/min, and carotid cross-sectional area was 0.85 ± 0.04 cm2. Central venous pressure (CVP) was 4 ± 2 mmHg, jugular flow was 0.7 ± 0.2 l/min, and jugular cross-sectional area was 0.14 ± 0.04 cm2 ( n = 4). Carotid arterial and jugular venous pressures at head level were 118 ± 9 and −7 ± 4 mmHg, respectively. When the head was lowered, MAP decreased to 131 ± 13 mmHg, while carotid cross-sectional area and flow remained unchanged. Cardiac output was reduced by 30%, CVP decreased to −1 ± 2 mmHg ( P < 0.01), and jugular flow ceased as the jugular cross-sectional area increased to 3.2 ± 0.6 cm2 ( P < 0.01), corresponding to accumulation of ∼1.2 l of blood in the veins. When the head was raised, the jugular veins collapsed and blood was returned to the central circulation, and CVP and cardiac output were restored. The results demonstrate that in the upright-positioned, anesthetized giraffe cerebral blood flow is governed by arterial pressure without support of a siphon mechanism and that when the head is lowered, blood accumulates in the vein, affecting MAP.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

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