Acute hyperoxia reveals tonic influence of peripheral chemoreceptors on systemic vascular resistance in heart failure patients

AbstractPeripheral chemoreceptors’ (PCh) hyperactivity increases sympathetic tone. An augmented acute ventilatory response to hypoxia, being a marker of PCh oversensitivity, was also identified as a marker of poor prognosis in HF. However, not much is known about the tonic (chronic) influence of PCh on cardio-respiratory parameters. In our study 30 HF patients and 30 healthy individuals were exposed to 100% oxygen for 1 min during which minute ventilation and hemodynamic parameters were non-invasively recorded. Systemic vascular resistance (SVR) and mean arterial pressure (MAP) responses to acute hyperoxia differed substantially between HF and control. In HF hyperoxia caused a significant drop in SVR in early stages with subsequent normalization, while increase in SVR was observed in controls. MAP increased in controls, but remained unchanged in HF. Bilateral carotid bodies excision performed in two HF subjects changed the response to hyperoxia towards the course seen in healthy individuals. These differences may be explained by the domination of early vascular reaction to hyperoxia in HF by vasodilation due to the inhibition of augmented tonic activity of PCh. Otherwise, in healthy subjects the vasoconstrictive action of oxygen remains unopposed. The magnitude of SVR change during acute hyperoxia may be used as a novel method for tonic PCh activity assessment.

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Physiologic and hemodynamic changes in patients undergoing open abdominal cytoreductive surgery with hyperthermic intraperitoneal chemotherapy

Journal of International Medical Research ◽

10.1177/0300060520983263 ◽

2021 ◽

Vol 49 (1) ◽

pp. 030006052098326

Author(s):

Myoung Hwa Kim ◽

Young Chul Yoo ◽

Sun Joon Bai ◽

Kang-Young Lee ◽

Nayeon Kim ◽

...

Keyword(s):

Body Temperature ◽

Systemic Vascular Resistance ◽

Vascular Resistance ◽

Intraperitoneal Chemotherapy ◽

Cytoreductive Surgery ◽

Hyperthermic Intraperitoneal Chemotherapy ◽

Resistance Index ◽

Volume Index ◽

Hemodynamic Changes ◽

Arterial Blood

Objective We aimed to determine the physiological and hemodynamic changes in patients who were undergoing hyperthermic intraperitoneal chemotherapy (HIPEC) cytoreductive surgeries. Methods This prospective, observational study enrolled 21 patients who were undergoing elective cytoreductive surgery with HIPEC at our hospital over 2 years. We collected vital signs, hemodynamic parameters including global end-diastolic volume index (GEVI) and extravascular lung water index (ELWI) using the VolumeView™ system, and arterial blood gas analysis from all patients. Data were recorded before skin incision (T1); 30 minutes before HIPEC initiation (T2); 30 (T3), 60 (T4), and 90 (T5) minutes after HIPEC initiation; 30 minutes after HIPEC completion (T6); and 10 minutes before surgery completion (T7). Results Patients showed an increase in body temperature and cardiac index and a decrease in the systemic vascular resistance index. GEDI was 715.4 (T1) to 809.7 (T6), and ELWI was 6.9 (T1) to 7.3 (T5). Conclusions HIPEC increased patients’ body temperature and cardiac output and decreased systemic vascular resistance. Although parameters that were extracted from the VolumeView™ system were within their normal ranges, transpulmonary thermodilution approach is helpful in intraoperative hemodynamic management during open abdominal cytoreductive surgery with HIPEC. Trial registry name: ClinicalTrials.gov Trial registration number: NCT02325648 URL: https://clinicaltrials.gov/ct2/results?cond=NCT02325648&term

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Investigation of thermal changes in the thyroid gland region of individuals with hypothyroidism and fibromyalgia by analyzing the temperature of brown adipose tissue

Scientific Reports ◽

10.1038/s41598-021-85974-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ana Paula Christakis Costa ◽

Joaquim Miguel Maia ◽

Marcos Leal Brioschi ◽

José Eduardo de Melo Mafra Machado

Keyword(s):

Adipose Tissue ◽

Thyroid Gland ◽

Brown Adipose Tissue ◽

Electronic Medical Records ◽

Medical Records ◽

Infrared Camera ◽

Healthy Individuals ◽

Brown Adipose ◽

Thermal Changes ◽

And Control

AbstractThis exploratory retrospective study aims to investigate the thermal changes in the thyroid gland region of patients with hypothyroidism and fibromyalgia by analyzing the temperature of the brown adipose tissue (BAT). A total of 166 individuals from 1000 thermographic electronic medical records were classified into four groups: Group HP + FM-50 individuals with hypothyroidism and fibromyalgia; Group FM-56 individuals with fibromyalgia only; Group HP-30 individuals with hypothyroidism only, and Group Control-30 healthy individuals. The thermal images from the electronic medical records were acquired by a FLIR T650SC infrared camera (used for thermometry) and the temperature data for each group were statistically analyzed. Group HP + FM showed r = 0, meaning that the average temperatures of the thyroid and BAT are independent of each other. Groups FM, HP and Control showed r = 1, meaning that the average temperatures of the thyroid and BAT were directly related. Our findings showed that the average temperatures of the thyroid and BAT regions are similar. Also, there was no correlation between thyroid gland temperature and the presence of hypothyroidism or fibromyalgia using thermometry.

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Ventilatory effects of hypoxia and adenosine infusion in patients after bilateral carotid endarterectomy

Clinical Science ◽

10.1042/cs0780025 ◽

1990 ◽

Vol 78 (1) ◽

pp. 25-31 ◽

Cited By ~ 13

Author(s):

T. L. Griffiths ◽

S. J. Warren ◽

A. D. B. Chant ◽

S. T. Holgate

Keyword(s):

Carotid Endarterectomy ◽

Ventilatory Response ◽

Adenosine Infusion ◽

Respiratory Drive ◽

Stimulant Effect ◽

Carotid Bodies ◽

Ventilatory Drive ◽

Bilateral Carotid ◽

Respiratory Stimulant ◽

Ventilatory Effects

1. We have studied the carotid body contribution to hypoxic respiratory drive, using a hypoxic/hyperoxic switching technique, and the ventilatory response to intravenous infusion of adenosine, a recently described respiratory stimulant, in five patients with bilateral carotid endarterectomy. 2. The contribution made by the carotid bodies to total ventilatory drive during hypoxia varied from 2.5% to 45.9%. 3. The ventilatory response to adenosine infusion varied from a 7% decrease to a 25% increase in ventilation. 4. Those patients with intact hypoxic ventilatory drive showed respiratory stimulation, whereas of the two patients with attenuated chemoreflexes, one showed no stimulation and the other depression of ventilation in response to adenosine infusion. 5. We conclude that adenosine exerts its respiratory stimulant effect via an action on the peripheral chemoreceptors. This may coexist with a centrally mediated respiratory depression that is masked when the carotid bodies are intact.

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Empagliflozin does not change cardiac index nor systemic vascular resistance but rapidly improves left ventricular filling pressure in patients with type 2 diabetes: a randomized controlled study

Cardiovascular Diabetology ◽

10.1186/s12933-020-01175-5 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Matthias Rau ◽

Kirsten Thiele ◽

Niels-Ulrik Korbinian Hartmann ◽

Alexander Schuh ◽

Ertunc Altiok ◽

...

Keyword(s):

Cardiac Index ◽

Systemic Vascular Resistance ◽

Vascular Resistance ◽

Resistance Index ◽

Stroke Volume Index ◽

Left Ventricular ◽

Volume Index ◽

Hemodynamic Parameters ◽

Mitral Inflow ◽

Ventricular Filling Pressure

Abstract Background In the EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial) treatment with the sodium-glucose cotransporter-2 (SGLT2) inhibitor empagliflozin significantly reduced heart failure hospitalization (HHF) in patients with type 2 diabetes mellitus (T2D) and established cardiovascular disease. The early separation of the HHF event curves within the first 3 months of the trial suggest that immediate hemodynamic effects may play a role. However, hitherto no data exist on early effects of SGLT2 inhibitors on hemodynamic parameters and cardiac function. Thus, this study examined early and delayed effects of empagliflozin treatment on hemodynamic parameters including systemic vascular resistance index, cardiac index, and stroke volume index, as well as echocardiographic measures of cardiac function. Methods In this placebo-controlled, randomized, double blind, exploratory study patients with T2D were randomized to empagliflozin 10 mg or placebo for a period of 3 months. Hemodynamic and echocardiographic parameters were assessed after 1 day, 3 days and 3 months of treatment. Results Baseline characteristics were not different in the empagliflozin (n = 22) and placebo (n = 20) group. Empagliflozin led to a significant increase in urinary glucose excretion (baseline: 7.3 ± 22.7 g/24 h; day 1: 48.4 ± 34.7 g/24 h; p < 0.001) as well as urinary volume (1740 ± 601 mL/24 h to 2112 ± 837 mL/24 h; p = 0.011) already after one day compared to placebo. Treatment with empagliflozin had no effect on the primary endpoint of systemic vascular resistance index, nor on cardiac index, stroke volume index or pulse rate at any time point. In addition, echocardiography showed no difference in left ventricular systolic function as assessed by left ventricular ejections fraction and strain analysis. However, empagliflozin significantly improved left ventricular filling pressure as assessed by a reduction of early mitral inflow velocity relative to early diastolic left ventricular relaxation (E/eʹ) which became significant at day 1 of treatment (baseline: 9.2 ± 2.6; day 1: 8.5 ± 2.2; p = 0.005) and remained apparent throughout the study. This was primarily attributable to reduced early mitral inflow velocity E (baseline: 0.8 ± 0.2 m/s; day 1: 0.73 ± 0.2 m/sec; p = 0.003). Conclusions Empagliflozin treatment of patients with T2D has no significant effect on hemodynamic parameters after 1 or 3 days, nor after 3 months, but leads to rapid and sustained significant improvement of diastolic function. Trial registration EudraCT Number: 2016-000172-19; date of registration: 2017-02-20 (clinicaltrialregister.eu)

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Ventilatory and hyperkalemic responses to incremental exercise after propranolol treatment

Journal of Applied Physiology ◽

10.1152/jappl.1994.77.4.1907 ◽

1994 ◽

Vol 77 (4) ◽

pp. 1907-1912 ◽

Cited By ~ 7

Author(s):

D. A. Schneider ◽

M. T. McEniery ◽

C. Solomon ◽

J. Jurimae ◽

M. S. Wehr

Keyword(s):

Minute Ventilation ◽

Plasma Potassium ◽

Muscle Afferents ◽

Incremental Exercise ◽

Co2 Production ◽

Beta Blockade ◽

Adrenergic Blockade ◽

Propranolol Treatment ◽

Positive Correlations ◽

And Control

The purpose of the present study was to examine the relationship of plasma potassium (K+) and minute ventilation (VE) during incremental cycling (20 W/2 min) under conditions of beta-adrenergic blockade (80 mg of propranolol) and placebo in six untrained male subjects. No significant differences existed between treatments in O2 uptake, CO2 production, blood lactate, pH, or VE during the submaximal work stages of incremental exercise common to both treatments (20–220 W). During exercise with beta-blockade, plasma K+ concentrations were found to be significantly elevated compared with control levels at every work stage except 20 W. Significant positive correlations between VE and plasma K+ were found during both beta-blockade (r = 0.99) and control conditions (r = 1.00). Although the high correlation between VE and K+ was not altered with beta-blockade, propranolol treatment resulted in a significant reduction in the slope of this relationship during incremental exercise (P < 0.01). These findings suggest that 1) beta-blockade decreases the VE-K+ relationship observed during exercise and 2) K+ stimulation of muscle afferents is not an important signal in the control of exercise ventilation.

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