A simplified paired neck chamber for the demonstration of baroreflex blood pressure regulation.

1999 ◽  
Vol 277 (6) ◽  
pp. S60 ◽  
Author(s):  
N M Raine ◽  
N T Cable
Keyword(s):  
Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Chamber Pressure ◽  
Variable Pressure ◽  
Performance Tests ◽  
Pressure Regulation ◽  
Response Relationship ◽  
Chamber Method ◽  
Stimulus Response ◽  
Neck Chamber

In this investigation a simplified variable-pressure paired neck chamber was developed as a practical alternative to traditional neck collar designs used to study the arterial baroreceptor reflex in humans. The purpose of this new design was to extend the use of the noninvasive neck chamber method of baroreceptor investigation to teachers of physiology. Performance tests indicate that these new chambers are capable of delineating the stimulus-response relationship for both the blood pressure baroreflex [sensitivity = 0.425 +/- 0.13 mmHg mean arterial pressure (MAP)/mmHg neck chamber pressure (NCP); range = 24.9 +/- 4.6 mmHg MAP] and the heart rate baroreflex (sensitivity 0.273 +/- 0.12 beats.min-1.mmHg NCP-1; range = 16.7 +/- 6.8 beats/min). This was achieved by applying localized positive and negative air pressures to the carotid sinuses throughout the range from +60 to -60 mmHg in steps of 20 mmHg. This simplified neck chamber method offers distinct methodological advantages over traditional neck collars, making it a valuable tool for demonstrating baroreflex regulation of the circulation.

The Influence of Habitual Breaks in Sedentary Time on Cardiovagal Baroreflex Function

2021 ◽  
Author(s):  
Myles W. O'Brien ◽  
Amera Al-Hinnawi ◽  
Yanlin Wu ◽  
Jennifer L. Petterson ◽  
Madeline E. Shivgulam ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Cardiovascular Health ◽  
Sedentary Time ◽  
Independent Predictor ◽  
Pressure Control ◽  
Pressure Regulation ◽  
Sedentary Breaks ◽  
Breaks In Sedentary Time ◽  
The Impact

Sedentary time (ST) has recently been included in the 24-h activity guidelines. However, the impact of habitual sedentary patterns on autonomic cardiovascular regulation are unclear. We tested the hypothesis that more ST and fewer sedentary breaks were associated with lower cardiovagal baroreflex sensitivity. More frequent sedentary breaks, but not total ST, was independently and positively associated with vagally-mediated blood pressure control. Breaking up ST could be more important than total ST for cardiovascular health. Novelty: Breaks in sedentary time is an independent predictor of cardiovagal baroreflex sensitivity, with more frequent breaks associated with better vagally-mediated blood pressure regulation.

scholarly journals From the First Spectral Analysis of Blood Pressure Variability in the World to the Present Time: Contribution of the Department of Physiology of the Faculty of Medicine, Masaryk University, Brno

2013 ◽  
pp. 341-350 ◽  
Author(s):  
Z. NOVÁKOVÁ
Keyword(s):  
Blood Pressure ◽  
Spectral Analysis ◽  
Baroreflex Sensitivity ◽  
Risk Index ◽  
Blood Pressure Measurement ◽  
Blood Pressure Regulation ◽  
Pressure Regulation ◽  
Prevention Of Hypertension ◽  
Relationship Of ◽  
The Relationship

The review shows the significance of blood pressure regulation studies conducted during several decades at the Department of Physiology, Faculty of Medicine, Masaryk University, Brno. Continuous non-invasive blood pressure measurement was first introduced and patented here and, with the obtained data, the first spectral analysis of blood pressure was performed. This method was used in many different physiological studies on the relationship of blood pressure regulation to circulatory parameters, breathing, and baroreflex sensitivity. The article deals with studies on risk stratification of sudden cardiac death according to decreased baroreflex sensitivity, 24-hour heart rate variability, the amount of extrasystoles and late potentials. Importance of the new method of determination of one summation risk index is described here. A summary of the new conception of the relationship between low baroreflex sensitivity and hypertension is presented. Here, not only pathological changes of the vessel wall but also increased sympathetic activity and genetic predisposition play a role. Importance of studies conducted in young adults is highlighted, as inherited BRS decrease contributes to earlier blood pressure increase in the young. This research is highly topical, since prevention of hypertension in childhood is possible. Recent studies are dedicated to blood pressure regulation in young diabetics.

The Variable-Pressure Neck-Chamber Method for Studying the Carotid Baroreflex in Man

1977 ◽  
Vol 53 (2) ◽  
pp. 165-171 ◽  
Author(s):  
J. Ludbrook ◽  
G. Mancia ◽  
A. Ferrari ◽  
A. Zanchetti
Keyword(s):  
Negative Pressure ◽  
Carotid Sinus ◽  
Venous Blood ◽  
Baroreceptor Reflex ◽  
Variable Pressure ◽  
Positive Pressure ◽  
Chamber Method ◽  
Carotid Baroreceptor ◽  
Pressure Changes ◽  
Neck Chamber

1. The variable-pressure neck-chamber method was analysed in ten healthy volunteer subjects to determine its suitability for the study of the carotid baroreceptor reflex in man. 2. Positive and negative pressures applied to the neck (range ± 60 mmHg) were always transmitted linearly to a tissue catheter outside the carotid sinus, but only 86% of positive pressure, and 64% of negative pressure. Tissue pressures were confirmed by simultaneous measurement in the internal jugular vein adjacent to the carotid sinus. 3. Positive and negative pressure changes within the above range did not alter Po2 of internal jugular venous blood, suggesting that cerebral blood flow was unaltered. 4. Positive pressure changes induced reflex pressor responses of similar magnitude at arterial Po2 12·8 and 70·1 kPa (96 and 527 mmHg), suggesting that the carotid chemoreceptors were not involved. 5. It is concluded that the variable-pressure neck chamber is a valid method for selectively studying the carotid baroreceptor reflex in man. However, transmission of external pneumatic pressure to the carotid sinus is imperfect and greater for positive than for negative pressure. This must be recognized to avoid underestimation of gain and distortion of shape of the reflex.

Spontaneous baroreflex control of heart rate during exercise and muscle metaboreflex activation in heart failure

2007 ◽  
Vol 293 (3) ◽  
pp. H1929-H1936 ◽  
Author(s):  
Ferdinando Iellamo ◽  
Javier A. Sala-Mercado ◽  
Masashi Ichinose ◽  
Robert L. Hammond ◽  
Marco Pallante ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Baroreflex Sensitivity ◽  
Left Ventricular ◽  
Dynamic Exercise ◽  
Response Relationship ◽  
Baroreflex Control ◽  
Muscle Metaboreflex ◽  
Stimulus Response ◽  
Spontaneous Baroreflex

In heart failure (HF), there is a reduced baroreflex sensitivity at rest, and during dynamic exercise there is enhanced muscle metaboreflex activation (MRA). However, how the arterial baroreflex modulates HR during exercise is unknown. We tested the hypothesis that spontaneous baroreflex sensitivity (SBRS) is attenuated during exercise in HF and that MRA further depresses SBRS. In seven conscious dogs we measured heart rate (HR), cardiac output, and left ventricular systolic pressure at rest and during mild and moderate dynamic exercise, before and during MRA (via imposed reductions of hindlimb blood flow), and before and after induction of HF (by rapid ventricular pacing). SBRS was assessed by the sequences method. In control, SBRS was reduced from rest with a progressive resetting of the baroreflex stimulus-response relationship in proportion to exercise intensity and magnitude of MRA. In HF, SBRS was significantly depressed in all settings; however, the changes with exercise and MRA occurred with a pattern similar to the control state. As in control, the baroreflex stimulus-response relationship showed an intensity- and muscle metaboreflex (MMR)-dependent rightward and upward shift. The results of this study indicate that HF induces an impairment in baroreflex control of HR at rest and during exercise, although the effects of exercise and MRA on SBRS occur with a similar pattern as in control, indicating the persistence of some vagal activity.

A Modified Method of Quantifying the Carotid Baroreceptor-Heart Rate Reflex in Man: The Effect of Age and Blood Pressure

1989 ◽  
Vol 77 (2) ◽  
pp. 223-228 ◽  
Author(s):  
M. R. Cowie ◽  
J. M. Rawles
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Baroreflex Sensitivity ◽  
Rate Sensitivity ◽  
Modified Method ◽  
Carotid Baroreceptor ◽  
Blood Pressures ◽  
The Mean ◽  
Neck Chamber ◽  
Effect Of Age

1. Carotid baroreceptor-heart rate sensitivity has been measured non-invasively by a modified neck-chamber method that utilizes all cardiac intervals recorded in 6 min during 84 respiratory cycles. 2. In a replication study in 10 subjects the mean baroreflex sensitivity was 5.52 ms/mmHg and the mean (sd) difference between determinations was 0.70 (0.74) ms/mmHg. 3. Baroreflex sensitivity was measured in 48 untreated subjects of mean age 43 (range 20–71) years with blood pressures ranging from 104 to 202 mmHg (13.9 to 26.9 kPa) systolic and 52 to 120 mmHg (6.9 to 16.0 kPa) diastolic [average 142/87 mmHg (18.9/11.6 kPa)]. Both systolic and diastolic pressures correlated with age (r = 0.53, P < 0.001 and r = 0.44, P < 0.01). 4. Baroreflex sensitivity determined throughout respiration was log-normally distributed with a median value of 2.24 ms/mmHg, which declined with age (r = −0.63, P < 0.001). 5. After allowing for the effects of age, baroreflex sensitivity throughout respiration was not independently related to either systolic or diastolic blood pressure.

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