Low-frequency fluctuations in heart rate, cardiac output and mean arterial pressure in humans: what are the physiological relationships?

2011 ◽  
Vol 29 (7) ◽  
pp. 1327-1336 ◽  
Author(s):  
Maja Elstad ◽  
Lars Walløe ◽  
Ki H Chon ◽  
Karin Toska
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Low Frequency ◽  
Frequency Fluctuations

The Effects of Increasing Plasma Concentrations of Dexmedetomidine in Humans

2000 ◽  
Vol 93 (2) ◽  
pp. 382-394 ◽  
Author(s):  
Thomas J. Ebert ◽  
Judith E. Hall ◽  
Jill A. Barney ◽  
Toni D. Uhrich ◽  
Maelynn D. Colinco
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Pulmonary Artery ◽  
Arterial Pressure ◽  
Plasma Concentrations ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Central Venous ◽  
Pressor Test

Background This study determined the responses to increasing plasma concentrations of dexmedetomidine in humans. Methods Ten healthy men (20-27 yr) provided informed consent and were monitored (underwent electrocardiography, measured arterial, central venous [CVP] and pulmonary artery [PAP] pressures, cardiac output, oxygen saturation, end-tidal carbon dioxide [ETCO2], respiration, blood gas, and catecholamines). Hemodynamic measurements, blood sampling, and psychometric, cold pressor, and baroreflex tests were performed at rest and during sequential 40-min intravenous target infusions of dexmedetomidine (0.5, 0.8, 1.2, 2.0, 3.2, 5.0, and 8.0 ng/ml; baroreflex testing only at 0.5 and 0.8 ng/ml). Results The initial dose of dexmedetomidine decreased catecholamines 45-76% and eliminated the norepinephrine increase that was seen during the cold pressor test. Catecholamine suppression persisted in subsequent infusions. The first two doses of dexmedetomidine increased sedation 38 and 65%, and lowered mean arterial pressure by 13%, but did not change central venous pressure or pulmonary artery pressure. Subsequent higher doses increased sedation, all pressures, and calculated vascular resistance, and resulted in significant decreases in heart rate, cardiac output, and stroke volume. Recall and recognition decreased at a dose of more than 0.7 ng/ml. The pain rating and mean arterial pressure increase to cold pressor test progressively diminished as the dexmedetomidine dose increased. The baroreflex heart rate slowing as a result of phenylephrine challenge was potentiated at both doses of dexmedetomidine. Respiratory variables were minimally changed during infusions, whereas acid-base was unchanged. Conclusions Increasing concentrations of dexmedetomidine in humans resulted in progressive increases in sedation and analgesia, decreases in heart rate, cardiac output, and memory. A biphasic (low, then high) dose-response relation for mean arterial pressure, pulmonary arterial pressure, and vascular resistances, and an attenuation of the cold pressor response also were observed.

scholarly journals Hemodynamic Changes Associated with Spinal Anesthesia for Cesarean Delivery in Severe Preeclampsia

2008 ◽  
Vol 108 (5) ◽  
pp. 802-811 ◽  
Author(s):  
Robert A. Dyer ◽  
Jenna L. Piercy ◽  
Anthony R. Reed ◽  
Carl J. Lombard ◽  
Leann K. Schoeman ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Spinal Anesthesia ◽  
Cesarean Delivery ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Severe Preeclampsia

Background Hemodynamic responses to spinal anesthesia (SA) for cesarean delivery in patients with severe preeclampsia are poorly understood. This study used a beat-by-beat monitor of cardiac output (CO) to characterize the response to SA. The hypothesis was that CO would decrease from baseline values by less than 20%. Methods Fifteen patients with severe preeclampsia consented to an observational study. The monitor employed used pulse wave form analysis to estimate nominal stroke volume. Calibration was by lithium dilution. CO and systemic vascular resistance were derived from the measured stroke volume, heart rate, and mean arterial pressure. In addition, the hemodynamic effects of phenylephrine, the response to delivery and oxytocin, and hemodynamics during recovery from SA were recorded. Hemodynamic values were averaged for defined time intervals before, during, and after SA. Results Cardiac output remained stable from induction of SA until the time of request for analgesia. Mean arterial pressure and systemic vascular resistance decreased significantly from the time of adoption of the supine position until the end of surgery. After oxytocin administration, systemic vascular resistance decreased and heart rate and CO increased. Phenylephrine, 50 mug, increased mean arterial pressure to above target values and did not significantly change CO. At the time of recovery from SA, there were no clinically relevant changes from baseline hemodynamic values. Conclusions Spinal anesthesia in severe preeclampsia was associated with clinically insignificant changes in CO. Phenylephrine restored mean arterial pressure but did not increase maternal CO. Oxytocin caused transient marked hypotension, tachycardia, and increases in CO.

scholarly journals COMPARATIVE CHARACTERISTICS OF THE DYNAMICS OF CARDIOVASCULAR AND RESPIRATORY EFFECTS OF PNEUMOPERITONEUM BASED ON CARBON DIOXIDE AND ARGON IN LAPAROSCOPIC CHOLECYSTECTOMY

2021 ◽  
pp. 90-95
Author(s):  
O. L. Tkachuk ◽  
R. L. Parakhoniak ◽  
S. V. Melnyk ◽  
O. O. Tkachuk-Hryhorchuk
Keyword(s):  
Carbon Dioxide ◽  
Heart Rate ◽  
Cardiac Output ◽  
Laparoscopic Cholecystectomy ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Negative Impact ◽  
Abdominal Pressure ◽  
The Mean ◽  
Respiratory Systems

Pneumoperitoneum is one of the most critical components of laparoscopic surgery, which has a negative effect on gas exchange and stress to circulatory buffering system. One of the top priorities of laparoscopic technologies is to minimize the impact on the respiratory and cardiovascular systems, metabolic dynamics and compensatory abilities of homeostasis. The main goal of this research work is to compare the effects of carboxyperitoneum and argonoperitoneum on the intraoperative dynamics of CO2 concentration as well as cardiovascular and respiratory characteristics in patients undergoing laparoscopic cholecystectomy for various forms of cholelithiasis. Materials and methods. Four experimental groups involved patients based on their nosological form of cholelithiasis and the gas used to induce pneumoperitoneum. All patients underwent laparoscopic cholecystectomy by means of standard procedure. Either medical carbon dioxide or medical argon was used to induce pneumoperitoneum. Intraoperative monitoring of blood carbon dioxide levels PaCO2 was performed by taking venous blood every 15 minutes. Capnometry was performed by means of mainstream analysis using “BIOMED” BM1000C modular patient monitor by recording the discrete values of PetCO2 every 15 minutes, as well as by analyzing photocopies of capnography curves every 15 minutes. Intraoperative echocardiography was performed to identify the mean arterial pressure (MAP), heart rate (HR) and cardiac output (CO) in order to assess the effects of different types of pneumoperitoneum on the cardiovascular system. Results. The obtained data confirm the expected difference in the indices of cardiorespiratory functions between patients with acute cholecystitis and cholelithiasis without signs of inflammation. The investigation revealed that under the influence of pneumoperitoneum, heart rate and mean arterial pressure increase, while the cardiac output decreases. The respiratory pressure marker depends more on the intra-abdominal pressure and presumably the patient’s body type than on the presence of inflammatory syndrome. Argon insufflation has a slight negative impact on the cardiovascular system. Particularly, the mean arterial pressure and heart rate increase, while the cardiac output marker is less decreased as compared to the use of carbon dioxide. Abdominal pressure has a significant effect on the cardiovascular and respiratory systems regardless of the used type of gas. The combination of high intra-abdominal pressure with the elevated head end of the operating table, which is a common practise during cholecystectomy, has especially great influence on cardiovascular and respiratory functions. Operation which is carried out at decreased pressure allows reducing the deviations of practically all indices. Conclusions. Thus, the cardiovascular and respiratory systems adapt under the influence of pneumoperitoneum, providing compensation for the negative effects of mechanical and resorptive-metabolic character. Compensatory-adaptive abilities of the cardiovascular and respiratory systems increase with the decrease of intra-abdominal pressure. The use of argon as a working gas for insufflation into the abdominal cavity during laparoscopy reduces the negative impact of pneumoperitoneum on the cardiovascular and respiratory systems, providing a greater reserve of homeostatic and buffer systems of the body.

Hemodynamic effects of neurohypophyseal peptides with antidiuretic activity in dogs

1985 ◽  
Vol 249 (5) ◽  
pp. H1001-H1008 ◽  
Author(s):  
J. Schwartz ◽  
J. F. Liard ◽  
C. Ott ◽  
A. W. Cowley
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Plasma Renin Activity ◽  
Peripheral Resistance ◽  
Cardiovascular Effects ◽  
Plasma Renin ◽  
Hemodynamic Effects ◽  
Antidiuretic Activity

Arginine vasopressin (AVP) is known to produce increases in total peripheral resistance (TPR) and mean arterial pressure (MAP) and decreases in heart rate (HR), cardiac output (CO), and plasma renin activity (PRA). Some recent observations with AVP and synthetic analogues have suggested that under certain conditions, AVP can induce cardiovascular and reninsecretory responses in the opposite directions. To characterize the receptors mediating these responses, the effects of AVP, oxytocin, and synthetic neurohypophyseal analogues with specific antidiuretic, vasoconstrictor, or oxytocic activities were studied in conscious dogs. AVP and 2-phenylalanine-8-ornithine-oxytocin (Phe2Orn8OT, a selective vasoconstrictor agonist) produced similar responses when infused at 10 ng X kg-1 X min-1. That is, TPR and MAP increased, and CO, HR, and PRA decreased. Pretreatment with a selective vasoconstrictor antagonist, [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid) 2-(O-methyl)tyrosine]AVP, abbreviated d(CH2)5Tyr(Me)-AVP (10 micrograms/kg), blocked the actions of Phe2Orn8OT. However, in the presence of d(CH2)5Tyr(Me)AVP, AVP actually decreased TPR and increased CO, HR, and PRA. An analogue with selective antidiuretic activity, 4-valine-8-D-AVP (VDAVP, 10 ng X kg-1 X min-1), produced the same effects as the combination of vasopressin plus d(CH2)5Tyr(Me)AVP. Neither the effects of VDAVP nor of AVP plus antagonist were blocked by propranolol (1 mg/kg). These data indicate that vasopressin, by its antidiuretic activity, produces cardiovascular effects that are opposite to many of those produced by its vasoconstrictor action and that these effects are not dependent on mediation by beta-adrenoceptors.

Dynamic exercise training in foxhounds. I. Oxygen consumption and hemodynamic responses

1985 ◽  
Vol 59 (1) ◽  
pp. 183-189 ◽  
Author(s):  
T. I. Musch ◽  
G. C. Haidet ◽  
G. A. Ordway ◽  
J. C. Longhurst ◽  
J. H. Mitchell
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Exercise Training ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Maximal Exercise ◽  
Submaximal Exercise ◽  
Maximal Heart Rate ◽  
O2 Consumption

Ten foxhounds were studied during maximal and submaximal exercise on a motor-driven treadmill before and after 8–12 wk of training. Training consisted of working at 80% of maximal heart rate 1 h/day, 5 days/wk. Maximal O2 consumption (VO2max) increased 28% from 113.7 +/- 5.5 to 146.1 +/- 5.4 ml O2 X min-1 X kg-1, pre- to posttraining. This increase in VO2max was due primarily to a 27% increase in maximal cardiac output, since maximal arteriovenous O2 difference increased only 4% above pretraining values. Mean arterial pressure during maximal exercise did not change from pre- to posttraining, with the result that calculated systemic vascular resistance (SVR) decreased 20%. There were no training-induced changes in O2 consumption, cardiac output, arteriovenous O2 difference, mean arterial pressure, or SVR at any level of submaximal exercise. However, if post- and pretraining values are compared, heart rate was lower and stroke volume was greater at any level of submaximal exercise. Venous lactate concentrations during a given level of submaximal exercise were significantly lower during posttraining compared with pretraining, but venous lactate concentrations during maximal exercise did not change as a result of exercise training. These results indicate that a program of endurance training will produce a significant increase in VO2max in the foxhound. This increase in VO2max is similar to that reported previously for humans and rats but is derived primarily from central (stroke volume) changes rather than a combination of central and peripheral (O2 extraction) changes.

scholarly journals Abnormal cardiovascular response to nitroglycerin in migraine

Cephalalgia ◽  
2019 ◽  
Vol 40 (3) ◽  
pp. 266-277
Author(s):  
Willebrordus PJ van Oosterhout ◽  
Guus G Schoonman ◽  
Dirk P Saal ◽  
Roland D Thijs ◽  
Michel D Ferrari ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Cardiovascular Response ◽  
Peripheral Resistance ◽  
Cardiovascular Responses ◽  
Initial Increase

Introduction Migraine and vasovagal syncope are comorbid conditions that may share part of their pathophysiology through autonomic control of the systemic circulation. Nitroglycerin can trigger both syncope and migraine attacks, suggesting enhanced systemic sensitivity in migraine. We aimed to determine the cardiovascular responses to nitroglycerin in migraine. Methods In 16 women with migraine without aura and 10 age- and gender-matched controls without headache, intravenous nitroglycerin (0.5 µg·kg−1·min−1) was administered. Finger photoplethysmography continuously assessed cardiovascular parameters (mean arterial pressure, heart rate, cardiac output, stroke volume and total peripheral resistance) before, during and after nitroglycerin infusion. Results Nitroglycerin provoked a migraine-like attack in 13/16 (81.2%) migraineurs but not in controls ( p = .0001). No syncope was provoked. Migraineurs who later developed a migraine-like attack showed different responses in all parameters vs. controls (all p < .001): The decreases in cardiac output and stroke volume were more rapid and longer lasting, heart rate increased, mean arterial pressure and total peripheral resistance were higher and decreased steeply after an initial increase. Discussion Migraineurs who developed a migraine-like attack in response to nitroglycerin showed stronger systemic cardiovascular responses compared to non-headache controls. The stronger systemic cardiovascular responses in migraine suggest increased systemic sensitivity to vasodilators, possibly due to insufficient autonomic compensatory mechanisms.

Cardiovascular Effects of Moxibustion at Jen Chung (Go-26) during Halothane Anesthesia in Dogs

1975 ◽  
Vol 03 (03) ◽  
pp. 245-261 ◽  
Author(s):  
Do Chil Lee ◽  
Myung O. Lee ◽  
Donald H. Clifford
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Stroke Volume ◽  
Total Peripheral Resistance ◽  
Venous Pressure ◽  
Peripheral Resistance ◽  
Cardiovascular Effects ◽  
Halothane Anesthesia

The cardiovascular effects of moxibustion at Jen Chung (Go-26) in 10 dogs under halothane anesthesia were compared to 5 dogs under halothane anesthesia without moxibustion and 5 dogs under halothane anesthesia in which moxibustion was effected at a neutral or non-acupuncture site. Cardiac output, stroke volume, heart rate, mean arterial pressure, central venous pressure, total peripheral resistance, pH, PaCO2, PaO2 and base deficit were measured over a two-hour period. A significant increase in cardiac output and stroke volume and a significant decrease in the total peripheral resistance were observed in the group which was stimulated by moxibustion at Jen Chun (Go-26). Heart rate, mean arterial pressure and pulse pressure were significantly increase during the early part of the two-hour period in the same group. The cardiovascular effects of moxibustion at Jen Chung (Go-26) which were observed at the end of the two hours were also present in two dogs in which measurements were continued for two additional hours.

Effects of mental stress on autonomic cardiac modulation during weightlessness

2010 ◽  
Vol 298 (1) ◽  
pp. H202-H209 ◽  
Author(s):  
André E. Aubert ◽  
Bart Verheyden ◽  
Constantin d′Ydewalle ◽  
Frank Beckers ◽  
Omer Van den Bergh
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
High Frequency ◽  
Mental Stress ◽  
Mental Arithmetic ◽  
Low Frequency ◽  
Arithmetic Task ◽  
Mental Arithmetic Task ◽  
Normalized Units

Sustained weightlessness affects all body functions, among these also cardiac autonomic control mechanisms. How this may influence neural response to central stimulation by a mental arithmetic task remains an open question. The hypothesis was tested that microgravity alters cardiovascular neural response to standardized cognitive load stimuli. Beat-to-beat heart rate, brachial blood pressure, and respiratory frequency were collected in five astronauts, taking part in three different short-duration (10 to 11 days) space missions to the International Space Station. Data recording was performed in supine position 1 mo before launch; at days 5 or 8 in space; and on days 1, 4, and 25 after landing. Heart rate variability (HRV) parameters were obtained in the frequency domain. Measurements were performed in the control condition for 10 min and during a 5-min mental arithmetic stress task, consisting of deducting 17 from a four-digit number, read by a colleague, and orally announcing the result. Our results show that over all sessions (pre-, in-, and postflight), mental stress induced an average increase in mean heart rate (Δ7 ± 1 beats/min; P = 0.03) and mean arterial pressure (Δ7 ± 1 mmHg; P = 0.006). A sympathetic excitation during mental stress was shown from HRV parameters: increase of low frequency expressed in normalized units (Δ8.3 ± 1.4; P = 0.004) and low frequency/high frequency (Δ1.6 ± 0.3; P = 0.001) and decrease of high frequency expressed in normalized units (Δ8.9 ± 1.4; P = 0.004). The total power was not influenced by mental stress. No effect of spaceflight was found on baseline heart rate, mean arterial pressure, and HRV parameters. No differences in response to mental stress were found between pre-, in-, and postflight. Our findings confirm that a mental arithmetic task in astronauts elicits sympathovagal shifts toward enhanced sympathetic modulation and reduced vagal modulation. However, these responses are not changed in space during microgravity or after spaceflight.

scholarly journals Cardiac output is not a significant source of low frequency mean arterial pressure variability

2013 ◽  
Vol 34 (9) ◽  
pp. 1207-1216 ◽  
Author(s):  
F Aletti ◽  
R L Hammond ◽  
J A Sala-Mercado ◽  
X Chen ◽  
D S O'Leary ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Low Frequency ◽  
Significant Source ◽  
Arterial Pressure Variability

Role of cardiac output in the pressor responses to graded muscle ischemia in man

1978 ◽  
Vol 45 (4) ◽  
pp. 574-580 ◽  
Author(s):  
F. Bonde-Petersen ◽  
L. B. Rowell ◽  
R. G. Murray ◽  
G. G. Blomqvist ◽  
R. White ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Conductance ◽  
Total Occlusion ◽  
Muscle Ischemia ◽  
Pressor Responses ◽  
Leg Exercise

Ten men repeatedly performed leg exercise (100–150 W) for 7 min with 30-min recovery periods interspersed. Both legs were made ischemic by total occlusion (OCCL), first for 3 min immediately after exercise and second for 30 s before exercise ended and 3 min into recovery. In addition legs were occluded for 3 min at rest (seated). OCCL at rest increased mean arterial pressure (MAP) by 9 Torr but did not affect cardiac output (CO) or heart rate (HR). OCCL at the end of exercise significantly raised MAP and HR above control values during 3-min recovery but CO was unaffected. OCCL 30 s before the end of exercise further increased MAP and HR significantly during recovery; MAP, CO, and HR were significantly increased above control values (CO by 2.1 1-min-1) during the 3rd min of recovery. We conclude that a strong reflex from ischemic legs maintains normal or elevated CO during leg OCCL. Thus CO was too high relative to total vascular conductance so that MAP was elevated.

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