Pharmacological dissection of components of the Valsalva maneuver in adrenergic failure

1991 ◽  
Vol 71 (4) ◽  
pp. 1563-1567 ◽  
Author(s):  
P. Sandroni ◽  
E. E. Benarroch ◽  
P. A. Low
Keyword(s):  
Blood Pressure ◽  
Phase Ii ◽  
Early Phase ◽  
Valsalva Maneuver ◽  
Late Phase ◽  
Adrenergic Regulation ◽  
Arterial Blood ◽  
Patient Groups ◽  
Age And Sex ◽  
Phase Iv

The arterial blood pressure (BP) components of the Valsalva maneuver (VM) were analyzed to ascertain whether they could be used as an index of adrenergic regulation of the circulation. We studied a control and three age- and sex-matched patient groups. Sympathetic adrenergic failure was graded on the basis of the degree of systolic BP (SBP) reduction during tilt: orthostatic hypotension (OH; SBP greater than 30 mmHg), borderline OH (BOH; 30 less than SBP greater than 10 mmHg), and sympathetic sudomotor failure (SSF). Controls exhibited a biphasic phase II, consisting of a modest decrement (early phase II) followed by a rise in BP (late phase II; II1) above resting values. All the patient groups including SSF exhibited a significant reduction in II1. An excessive BP fall in phase II and an absent phase IV overshoot were observed in the OH group. BOH and, to a lesser extent, SSF groups showed a significant reduction in phase IV overshoot. We conclude that BP changes during VM will detect adrenergic vasoconstrictor failure with greater sensitivity than orthostatic BP recordings.

scholarly journals Heat stress alters hemodynamic responses during the Valsalva maneuver

2010 ◽  
Vol 108 (6) ◽  
pp. 1591-1594 ◽  
Author(s):  
Scott L. Davis ◽  
Craig G. Crandall
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heat Stress ◽  
Phase Ii ◽  
Valsalva Maneuver ◽  
Late Phase ◽  
Thermal Conditions ◽  
Whole Body ◽  
Hemodynamic Responses ◽  
Arterial Blood

The Valsalva maneuver can be used as a noninvasive index of autonomic control of blood pressure and heart rate. The purpose of this investigation was to test the hypothesis that sympathetic mediated vasoconstriction, as referenced by hemodynamic responses during late phase II (phase IIb) of the Valsalva maneuver, is inhibited during whole body heating. Seven individuals (5 men, 2 women) performed three Valsalva maneuvers (each at a 30-mmHg expiratory pressure for 15 s) during normothermia and again during whole body heating (increase sublingual temperature ∼0.8°C via water-perfused suit). Each Valsalva maneuver was separated by a minimum of 5 min. Beat-to-beat mean arterial blood pressure (MAP) and heart rate were measured during each Valsalva maneuver, and responses for each phase were averaged across the three Valsalva maneuvers for both thermal conditions. Baseline MAP was not significantly different between normothermic (88 ± 11 mmHg) and heat stress (84 ± 9 mmHg) conditions. The change in MAP (ΔMAP) relative to pre-Valsalva MAP during phases IIa and IIb was significantly lower during heat stress (IIa = −20 ± 8 mmHg; IIb = −13 ± 7 mmHg) compared with normothermia (IIa = −1 ± 15 mmHg; IIb = 3 ± 13 mmHg). ΔMAP from pre-Valsalva baseline during phase IV was significantly higher during heat stress (25 ± 10 mmHg) compared with normothermia (8 ± 9 mmHg). Counter to the proposed hypothesis, the increase in MAP from the end of phase IIa to the end of phase IIb during heat stress was not attenuated. Conversely, this increase in MAP tended to be greater during heat stress relative to normothermia ( P = 0.06), suggesting that sympathetic activation may be elevated during this phase of the Valsalva while heat stressed. These data show that heat stress does not attenuate this index of vasoconstrictor responsiveness during the Valsalva maneuver.

Critical closing pressure explains cerebral hemodynamics during the Valsalva maneuver

1999 ◽  
Vol 86 (2) ◽  
pp. 675-680 ◽  
Author(s):  
Suzanne L. Dawson ◽  
Ronney B. Panerai ◽  
John F. Potter
Keyword(s):  
Blood Pressure ◽  
Valsalva Maneuver ◽  
Intrathoracic Pressure ◽  
Pulse Interval ◽  
Cerebrovascular Resistance ◽  
Arterial Blood ◽  
Critical Closing Pressure ◽  
Pressure Changes ◽  
Closing Pressure ◽  
Phase Iv

The Valsalva maneuver (VM), a voluntary increase in intrathoracic pressure of ∼40 mmHg, has been used to examine cerebral autoregulation (CA). During phase IV of the VM there are pronounced changes in mean arterial blood pressure (MABP), pulse interval, and cerebral blood flow (CBF), but the changes in CBF are of a much greater magnitude than those seen in MABP, a finding to date attributed to either a delay in activation of the CA mechanism or the inability of this mechanism to cope with the size and speed of the blood pressure changes involved. These changes in CBF also precede those in MABP, a pattern of events not explained by the physiological process of CA. Measurements of CBF velocity (transcranial Doppler) and MABP (Finapres) were performed in 53 healthy volunteers (aged 31–80 yr). By calculating beat-to-beat values of critical closing pressure (CCP) during the VM, we have found that this parameter suddenly drops at the start of phase IV, providing a coherent explanation for the large increase in CBF. If CCP is included in the estimation of cerebrovascular resistance, a temporal pattern more consistent with an autoregulatory response to the MABP overshoot is also found. CCP is intricately involved in the control of CBF during the VM and should be considered in the assessment of CA.

scholarly journals Perioperative metabolic acidosis: The Bradford Anaesthetic Department Acidosis Study

2018 ◽  
Vol 20 (1) ◽  
pp. 11-17 ◽  
Author(s):  
TO Lawton ◽  
A Quinn ◽  
SJ Fletcher
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Metabolic Acidosis ◽  
Early Phase ◽  
Time Course ◽  
Late Phase ◽  
Common Finding ◽  
Major Surgery ◽  
Arterial Blood ◽  
Early Fluid

Metabolic acidosis is considered deleterious but is common in post-surgical patients admitted to intensive care unit. We evaluated the prevalence and time course of metabolic acidosis in elective major surgery, and generated hypotheses about causes, by hourly arterial blood sampling in 92 patients. Metabolic acidosis began before incision and most had occurred by the next hour. Seventy-eight per cent of patients had a significant metabolic acidosis post-operatively. Two overlapping phases were observed. The early phase started before incision, characterised by a rising chloride and falling anion gap, unrelated to saline use. The late phase was partly associated with lactate, related to surgery type, and early fluids appeared protective. There was a trend towards longer intensive care unit (+1.3 days) and hospital (+3.2 days) stay with metabolic acidosis. This is the first large study of the evolution of this common finding, demonstrating a pre-incision component. The early phase appears unavoidable or unpredictable, but the late phase might be modified by early fluid administration. It remains unclear whether acidosis of this type should be avoided.

Influences of age and sex on endothelium-dependent vascular responses and arterial blood pressure in the rat

1994 ◽  
Vol 25 (4) ◽  
pp. 753-759 ◽  
Author(s):  
Raquel Molina ◽  
Manuel Sánchez ◽  
Agustín Hidalgo ◽  
M.JoséGarcía De Boto
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Vascular Responses ◽  
Arterial Blood ◽  
Age And Sex

scholarly journals Preserved autonomic function in amenorrheic athletes

2006 ◽  
Vol 101 (2) ◽  
pp. 590-597 ◽  
Author(s):  
Megan M. Wenner ◽  
Allen V. Prettyman ◽  
Raelene E. Maser ◽  
William B. Farquhar
Keyword(s):  
Phase Ii ◽  
Autonomic Function ◽  
Valsalva Maneuver ◽  
Cardiovascular Responses ◽  
Cardiovascular Regulation ◽  
Reproductive Hormones ◽  
Orthostatic Stress ◽  
Sinus Arrhythmia ◽  
Blood Pressure Responses ◽  
Phase Iv

Reproductive hormones such as estradiol and progesterone are known to influence autonomic cardiovascular regulation. The purpose of this study was to determine whether amenorrheic athletes (AA) have impaired autonomic cardiovascular regulation compared with eumenorrheic athletes (EA). Thirty-five athletes were tested: 13 AA (19 ± 1 yr), 13 EA (21 ± 1 yr), and 9 EA (23 ± 1 yr) on oral contraceptives (EA-OC). Multiple indexes of autonomic cardiovascular regulation were assessed: respiratory sinus arrhythmia (RSA), cardiovagal baroreflex sensitivity (BRS) via phase IV and phase II of the Valsalva maneuver, a spontaneous index of BRS, and the heart rate and blood pressure responses to orthostatic stress (20-min 60° head-up tilt). RSA was not different among the groups. There were no group differences in the spontaneous index of BRS (AA = 30 ± 6, EA = 24 ± 3, EA-OC = 29 ± 5 ms/mmHg) or in phase II (AA = 8 ± 2, EA = 7 ± 1, EA-OC = 8 ± 1 ms/mmHg) of the Valsalva. There was a difference in BRS during phase IV (AA = 21 ± 3, EA = 15 ± 1, EA-OC = 26 ± 6 ms/mmHg; ANOVA P = 0.04). Tukey's post hoc test indicated that BRS was greater in the EA-OC group compared with the EA group ( P = 0.04). There were no differences in cardiovascular responses to orthostatic stress among the groups. In conclusion, AA do not display signs of impaired autonomic function and orthostatic responses compared with EA or EA-OC during the follicular phase of the menstrual cycle.

CIRCULATORY INDICES AND THEIR RELATIONS WITH PHYSICAL STRENGTH OF KINH AND SAN DIU HIGH SCHOOL PUPILS IN TAM DAO DISTRICT, VINH PHUC PROVINCE

2020 ◽  
Vol 65 (10) ◽  
pp. 180-188
Author(s):  
Cuong Do Hong ◽  
Tinh Hoang Quy
Keyword(s):  
High School ◽  
Blood Pressure ◽  
Sex Factors ◽  
Male And Female ◽  
Physical Strength ◽  
Current Period ◽  
Arterial Blood ◽  
Proportional Relationship ◽  
Physical Index ◽  
Age And Sex

This research on morphological and physical strength was conducted on 795 pupils of high school (from 16 to 18 years), the ethnicity of Kinh (50.06%), San Diu (49.94%) in Tam Dao district, Vinh Phuc province. The objective of this research was to identify some morphological and physical strengths of male and female pupils aged 16 - 18, contributing to building Vietnamese biological values in the current period. The research results show that there were differences in morphological indicators: height was based on age and sex factors. The physical strength of the study was subjected to the normal group according to BMI. Circulatory indicators (heart rate, arterial blood pressure) had a proportional relationship to the morphological and physical index.

Abstract 413: Renal Cyclooxygenase-2 Expression And Hemodynamic Role During Angiotensin II-dependent Hypertension

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Alexis A Gonzalez ◽  
Torrance Green ◽  
Camille R Bourgeois ◽  
Christina Luffman ◽  
Minolfa C Prieto ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Late Phase ◽  
Renal Hemodynamics ◽  
Cyclooxygenase 2 ◽  
Kidney Cortex ◽  
Dependent Manner ◽  
Sprague Dawley ◽  
Arterial Blood ◽  
Cox 2

Intrarenal cyclooxygenase-2 (COX-2) activity is increased during activation of the renin-angiotensin-system (RAS) increasing synthesis of prostaglandin E2 (PGE2) and buffering the vasoconstrictor and antinatriuretic effects of angiotensin II (AngII). While AngII upregulates intrarenal COX-2 expression, it remains unclear if this occurs in a time-dependent manner, thereby impacting renal hemodynamics differently during the early and late phases of the development of high blood pressure in AngII-induced hypertension. Male Sprague-Dawley rats were infused with AngII (0.4 μg/min/kg). Systolic blood pressure (SBP), COX-2 expression and PGE2 tissue content and urinary excretion were evaluated at day 3, 7 and 14 of the AngII infusions. In acute studies we evaluated the effects of COX-2 inhibition at day 5-7 and day 14 on renal hemodynamic parameters. Chronic AngII infusions increased SBP from day 7 through 14: 162 ± 5 mmHg; and 198 ± 15 mmHg versus controls: 114 ± 10 mmHg; P<0.05. COX-2 mRNA and protein levels were high in kidney cortex only at day 3 (mRNA: 241 ± 56%, protein: 160 ± 21%, P<0.05 versus controls). Medullary COX-2 mRNA and protein were increased on days 3 (mRNA: 176 ± 20%, protein: 185 ± 32%, P<0.05 versus controls), 7 (mRNA: 189 ± 23%, protein: 158 ± 15%, P<0.05 versus controls) and 14 (mRNA: 148 ± 15%, protein: 135 ± 13%, P<0.05 versus controls). Urinary and medullary PGE2 increased by day 3 and remained elevated during days 7 and 14. COX-2 inhibition decreased GFR and renal blood flow in AngII infused rats during both the early and late phases. Interestingly, COX-2 inhibition decreased mean arterial blood pressure at day 14 of AngII-infusion (COX-2 inhibition: 124 ± 9 versus 140 ± 7 mmHg, P<0.05) but not during the early normotensive phase (COX-2 inhibition: 110 ± 4 versus 115± 4 mmHg, P=NS). These results indicate that enhanced medullary COX-2 expression and PGE2 production during both the early and late phases attenuates the effects of AngII on renal hemodynamics. However COX-2 inhibition at day 14 reduced blood pressure, suggesting that a vasoconstrictor COX-2 metabolite contributes to the hypertension during the late phase.

Cardiovagal Reflexes

2009 ◽  
pp. 661-676
Author(s):  
William P. Cheshire
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Phase Ii ◽  
Heart Rate Response ◽  
Valsalva Maneuver ◽  
Human Subjects ◽  
Simultaneous Recording ◽  
Deep Breathing ◽  
Noninvasive Technique ◽  
Phase Iv

Noninvasive cardiovascular tests are reliable and reproducible and are widely used to evaluate autonomic function in human subjects. The heart rate response to deep breathing is probably the most reliable test for assessing the integrity of the vagal afferent and efferent pathways to the heart. This is because respiratory sinus arrhythmia is a relatively pure test of cardiovagal function, whereas many other conditions, such as plasma volume, antecedent rest, and cardiac and peripheral sympathetic functions, factor into the Valsalva response. Heart rate variability to deep breathing is usually tested at a breathing frequency of 5 or 6 respirations per minute and decreases linearly with age. The Valsalva maneuver consists of a forced expiratory effort against resistance and produces mechanical (phases I and III) and reflex (phases II and IV) changes in arterial pressure and heart rate. When performed under continuous arterial pressure monitoring with a noninvasive technique, the Valsalva maneuver provides valuable information about the integrity of the cardiac parasympathetic, cardiac sympathetic, and sympathetic vasomotor outputs. The responses to the Valsalva maneuver are affected by the position of the subject and the magnitude and duration of the expiratory effort. In general, it is performed at an expiratory pressure of 40 mm Hg sustained for 15 seconds. The Valsalva ratio, the relationship between the maximal heart rate response during phase II (straining) and phase IV (after release of straining), has been considered a test of cardiac parasympathetic function. However, without simultaneous recording of arterial pressure, this may be misleading. An exaggerated decrease in arterial pressure during phase II suggests sympathetic vasomotor failure, whereas an absence of overshoot during phase IV indicates the inability to increase cardiac output and cardiac adrenergic failure.

Dynamic cerebral autoregulation during and after handgrip exercise in humans

2010 ◽  
Vol 108 (6) ◽  
pp. 1701-1705 ◽  
Author(s):  
Shigehiko Ogoh ◽  
Kohei Sato ◽  
Toshinari Akimoto ◽  
Anna Oue ◽  
Ai Hirasawa ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cerebral Autoregulation ◽  
Valsalva Maneuver ◽  
Maximum Voluntary Contraction ◽  
Static Exercise ◽  
Handgrip Exercise ◽  
Arterial Blood ◽  
Significant Difference ◽  
Acute Hypotension ◽  
Dynamic Cerebral Autoregulation

The purpose of the present study was to examine the effect of static exercise on dynamic cerebral autoregulation (CA). In nine healthy subjects at rest before, during, and after static handgrip exercise at 30% maximum voluntary contraction, the response to an acute drop in mean arterial blood pressure and middle cerebral artery mean blood velocity was examined. Acute hypotension was induced nonpharmacologically via rapid release of bilateral thigh occlusion cuffs. Subjects were instructed to avoid executing a Valsalva maneuver during handgrip. To quantify dynamic CA, the rate of regulation (RoR) was calculated from the change in cerebral vascular conductance index during the transient fall in blood pressure. There was no significant difference in RoR between rest (mean ± SE; 0.278 ± 0.052/s), exercise (0.333 ± 0.053/s), and recovery (0.305 ± 0.059/s) conditions ( P = 0.747). In addition, there was no significant difference in the rate of absolute cerebral vasodilatory response to acute hypotension between three conditions ( P = 0.737). This finding indicates that static exercise and related elevations in blood pressure do not alter dynamic CA.

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