scholarly journals High-CPAP Does Not Impede Cardiovascular Changes at Birth in Preterm Sheep

2021 ◽  
Vol 8 ◽  
Author(s):  
Tessa Martherus ◽  
Kelly J. Crossley ◽  
Karyn A. Rodgers ◽  
Janneke Dekker ◽  
Anja Demel ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiovascular System ◽  
Preterm Infants ◽  
Jugular Vein ◽  
Cardiovascular Changes ◽  
Blood Flows ◽  
Airway Pressures

Objective: Continuous positive airway pressures (CPAP) used to assist preterm infants at birth are limited to 4–8 cmH2O due to concerns that high-CPAP may cause pulmonary overexpansion and adversely affect the cardiovascular system. We investigated the effects of high-CPAP on pulmonary (PBF) and cerebral (CBF) blood flows and jugular vein pressure (JVP) after birth in preterm lambs.Methods: Preterm lambs instrumented with flow probes and catheters were delivered at 133/146 days gestation. Lambs received low-CPAP (LCPAP: 5 cmH2O), high-CPAP (HCPAP: 15 cmH2O) or dynamic HCPAP (15 decreasing to 8 cmH2O at ~2 cmH2O/min) for up to 30 min after birth.Results: Mean PBF was lower in the LCPAP [median (Q1–Q3); 202 (48–277) mL/min, p = 0.002] compared to HCPAP [315 (221–365) mL/min] and dynamic HCPAP [327 (269–376) mL/min] lambs. CBF was similar in LCPAP [65 (37–78) mL/min], HCPAP [73 (41–106) mL/min], and dynamic HCPAP [66 (52–81) mL/min, p = 0.174] lambs. JVP was similar at CPAPs of 5 [8.0 (5.1–12.4) mmHg], 8 [9.4 (5.3–13.4) mmHg], and 15 cmH2O [8.6 (6.9–10.5) mmHg, p = 0.909]. Heart rate was lower in the LCPAP [134 (101–174) bpm; p = 0.028] compared to the HCPAP [173 (139–205)] and dynamic HCPAP [188 (161–207) bpm] groups. Ventilation or additional caffeine was required in 5/6 LCPAP, 1/6 HCPAP, and 5/7 dynamic HCPAP lambs (p = 0.082), whereas 3/6 LCPAP, but no HCPAP lambs required intubation (p = 0.041), and 1/6 LCPAP, but no HCPAP lambs developed a pneumothorax (p = 0.632).Conclusion: High-CPAP did not impede the increase in PBF at birth and supported preterm lambs without affecting CBF and JVP.

The effects of artificial lung inflation on pulmonary blood flow and heart rate in the turtle Trachemys scripta.

1997 ◽  
Vol 200 (19) ◽  
pp. 2539-2545
Author(s):  
J Herman ◽  
T Wang ◽  
A W Smits ◽  
J W Hicks
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Lung Volume ◽  
Pulmonary Blood Flow ◽  
Trachemys Scripta ◽  
Spontaneous Ventilation ◽  
Lung Inflation ◽  
Cardiovascular Changes ◽  
Blood Flows ◽  
Stimulation Of

As for most ectothermic vertebrates, the breathing pattern of turtles is episodic, and pulmonary blood flow (Qpul) and heart rate (fH) normally increase several-fold during spontaneous ventilation. While some previous studies suggest that these cardiovascular changes are caused by stimulation of pulmonary stretch receptors (PSRs) during ventilation, it has been noted in other studies that blood flows often change prior to the initiation of breathing. Given the uncertainty regarding the role of PSRs in the regulation of central vascular blood flows, we examined the effect of manipulating lung volume (and therefore PSR stimulation) on blood flows and heart rate in the freshwater turtle Trachemys scripta. Turtles were instrumented with blood flow probes on the left aortic arch and the left pulmonary artery for measurements of blood flow, and catheters were inserted into both lungs for manipulation of lung volume. In both anaesthetized and fully recovered animals, reductions or increases in lung volume by withdrawal of lung gas or injection of air, N2, O2 or 10% CO2 (in room air) had no effect on blood flows. Furthermore, simulations of normal breathing bouts by withdrawal and injection of lung gas did not alter Qpul or fH. We conclude that stimulation of PSRs is not sufficient to elicit cardiovascular changes and that the large increase in Qpul and fH normally observed during spontaneous ventilation are probably caused by a simultaneous feedforward control of central origin.

scholarly journals Effect of aqueous solution of stevioside on pharmacological properties of some cardioactive drugs

2014 ◽  
Vol 71 (7) ◽  
pp. 667-672 ◽  
Author(s):  
Velibor Vasovic ◽  
Aleksandar Raskovic ◽  
Momir Mikov ◽  
Ivan Mikov ◽  
Boris Milijasevic ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Heart Rate ◽  
Cardiovascular System ◽  
Jugular Vein ◽  
Infusion Pump ◽  
Physiological Saline ◽  
Control Group ◽  
Pharmacological Properties ◽  
Group A ◽  
Cardioactive Drugs

Background/Aim. Stevioside is a glycoside that supposedly possesses a number of pharmacodynamic effects such as anti-infective, hypoglycemic, along with the beneficial influence on the cardiovascular system. The aim of this study was to determine the effect of rats pretreatment with aqueous solution of stevioside on pharmacological actions of adrenaline, metoprolol and verapamil. Methods. Rats were administered (intraperitoneally 200 mg/kg/day) stevioside as aqueous solution or physiological saline in the course of 5 days, then anaesthetized with urethane and the first ECG recording was made. The prepared jugular vein was connected to an infusion pump with adrenaline (0.1 mg/mL), verapamil (2.5 mg/mL) or metoprolol (1 mg/mL). Control animals, pretreated with saline, in addition to the mentioned drugs, were also infused with the solution of stevioside (200 mg/mL) in the course of recording ECG. Results. The infusion of stevioside produced no significant changes in ECG, even at a dose exceeding 1,600 mg/kg. In the control group, a dose of adrenaline of 0.07 ? 0.02 mg/kg decreased the heart rate, whereas in the steviosidepretreated rats this occurred at a significantly higher dose (0.13 ? 0.03 mg/kg). In stevioside-pretreated rats, the amount of verapamil needed to produce the decrease in heart rate was significantly lower compared to the control. The pretreatment with stevioside caused no significant changes in the parameters registered on ECG during infusion of metoprolol. Conclusion. The results suggest that pretreatment with stevioside may change the effect of adrenaline and verapamile on the heart rate.

Bifurcation in a Simple Model of the Cardiovascular System

2000 ◽  
Vol 39 (02) ◽  
pp. 118-121 ◽  
Author(s):  
S. Akselrod ◽  
S. Eyal
Keyword(s):  
Nonlinear Dynamics ◽  
Blood Pressure ◽  
Heart Rate ◽  
Fixed Point ◽  
Cardiovascular System ◽  
Modified Model ◽  
Mayer Waves ◽  
Sustained Oscillations ◽  
Human Cardiovascular System ◽  
Physiological Values

Abstract:A simple nonlinear beat-to-beat model of the human cardiovascular system has been studied. The model, introduced by DeBoer et al. was a simplified linearized version. We present a modified model which allows to investigate the nonlinear dynamics of the cardiovascular system. We found that an increase in the -sympathetic gain, via a Hopf bifurcation, leads to sustained oscillations both in heart rate and blood pressure variables at about 0.1 Hz (Mayer waves). Similar oscillations were observed when increasing the -sympathetic gain or decreasing the vagal gain. Further changes of the gains, even beyond reasonable physiological values, did not reveal another bifurcation. The dynamics observed were thus either fixed point or limit cycle. Introducing respiration into the model showed entrainment between the respiration frequency and the Mayer waves.

Dexamethasone Effect on Heart Rate Characteristics in Preterm Infants

PEDIATRICS ◽  
2016 ◽  
Vol 137 (Supplement 3) ◽  
pp. 478A-478A
Author(s):  
Karen D. Fairchild ◽  
Corrie Joy Alonzo
Keyword(s):  
Heart Rate ◽  
Preterm Infants

DEVELOPMENT OF A DEVICE FOR CONTROL OF THE STATE OF THE ORGANISM BASED ON PHOTOPLETISMOGRAPHY USING TECHNOLOGIES OF DIGITAL ADAPTIVE FILTRATION

2020 ◽  
pp. 100-107
Author(s):  
Алексей Дмитриевич Акишин ◽  
Иван Павлович Семчук ◽  
Александр Петрович Николаев
Keyword(s):  
Heart Rate ◽  
Cardiovascular System ◽  
Adaptive Filtering ◽  
Least Squares Method ◽  
Optimal Algorithm ◽  
Heart Diseases ◽  
Cardiac Activity ◽  
Motion Artifacts ◽  
The Body ◽  
Advantages And Disadvantages

Постоянно растущий интерес к разработке новых неинвазивных и безманжетных методов измерения параметров сердечной деятельности, использование которых давало бы возможность непрерывного и удаленного контроля сердечно-сосудистой системы, обуславливает актуальность данной работы. В многочисленных публикациях продолжаются обсуждения преимуществ и недостатков различных методов ранней диагностики сердечно-сосудистых заболеваний. Однако артефакты движения являются сильной помехой, мешающей точной оценке показателей функционирования сердечно-сосудистой системы. Одним из перспективных методов контроля является метод оценки физиологических параметров с использованием фотоплетизмографии. Данная статья посвящена разработке устройства для фотоплетизмографических исследований и алгоритмических методов обработки регистрируемых сигналов для обеспечения мониторинга сердечного ритма с заданной точностью. В работе используются технологии цифровой адаптивной фильтрации полученных сигналов для мониторинга сердечного ритма в условиях внешних механических и электрических помеховых воздействий, ухудшающих точностные характеристики системы, а также разработана архитектура системы и изготовлен макет устройства, который позволил провести измерения для определения оптимального алгоритма цифровой обработки сигналов. При использовании устройства применялись методы адаптивной фильтрации на основе фильтров Винера, фильтров на основе метода наименьших квадратов и Калмановской фильтрации. Разработанное устройство для фотоплетизмографических исследований обеспечило возможность мониторинга сердечного ритма с заданной точностью, контроля текущего состояния организма и может быть использовано в качестве средства диагностики заболеваний сердца The constantly growing interest in the development of new non-invasive and cuff-free methods for measuring the parameters of cardiac activity, the use of which would give the possibility of continuous and remote monitoring of the cardiovascular system, determines the relevance of this work. Numerous publications continue to discuss the advantages and disadvantages of various methods of early diagnosis of cardiovascular disease. However, motion artifacts are a strong hindrance to the accurate assessment of the performance of the cardiovascular system. One of the promising control methods is the method for assessing physiological parameters using photoplethysmography. This article is devoted to the development of a device for photoplethysmographic studies and algorithmic methods for processing recorded signals to ensure monitoring of the heart rate with a given accuracy. The work uses technologies of digital adaptive filtering of the received signals to monitor the heart rate in conditions of external mechanical and electrical interference, which worsen the accuracy characteristics of the system, as well as the architecture of the system and a prototype of the device, which made it possible to carry out measurements to determine the optimal algorithm for digital signal processing. When using the device, the methods of adaptive filtering based on Wiener filters, filters based on the least squares method and Kalman filtering were used. The developed device for photoplethysmographic studies provided the ability to monitor the heart rate with a given accuracy, control the current state of the body and can be used as a means of diagnosing heart diseases

Cardiovascular Responses to Muscle Stretching: A Systematic Review and Meta-analysis

2021 ◽  
Author(s):  
Ewan Thomas ◽  
Marianna Bellafiore ◽  
Ambra Gentile ◽  
Antonio Paoli ◽  
Antonio Palma ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiovascular System ◽  
Vascular Function ◽  
Meta Analysis ◽  
Random Effect ◽  
Cardiovascular Responses ◽  
Qualitative Description ◽  
Cross Sectional ◽  
Quantitative Synthesis

AbstractThe aim of this study will be to review the current body of literature to understand the effects of stretching on the responses of the cardiovascular system. A literature search was performed using the following databases: Scopus, NLM Pubmed and ScienceDirect. Studies regarding the effects of stretching on responses of the cardiovascular system were investigated. Outcomes regarded heart rate(HR), blood pressure, pulse wave velocity (PWV of which baPWV for brachial-ankle and cfPWV for carotid-femoral waveforms), heart rate variability and endothelial vascular function. Subsequently, the effects of each outcome were quantitatively synthetized using meta-analytic synthesis with random-effect models. A total of 16 studies were considered eligible and included in the quantitative synthesis. Groups were also stratified according to cross-sectional or longitudinal stretching interventions. Quality assessment through the NHLBI tools observed a “fair-to-good” quality of the studies. The meta-analytic synthesis showed a significant effect of d=0.38 concerning HR, d=2.04 regarding baPWV and d=0.46 for cfPWV. Stretching significantly reduces arterial stiffness and HR. The qualitative description of the studies was also supported by the meta-analytic synthesis. No adverse effects were reported, after stretching, in patients affected by cardiovascular disease on blood pressure. There is a lack of studies regarding vascular adaptations to stretching.

Noisy fluctuation of heart rate indicates cardiovascular system instability

2013 ◽  
Vol 113 (9) ◽  
pp. 2253-2261 ◽  
Author(s):  
Jacques-Olivier Fortrat ◽  
Charlotte Baum ◽  
Christian Jeanguillaume ◽  
Marc-Antoine Custaud
Keyword(s):  
Heart Rate ◽  
Cardiovascular System

Transcutaneous Oxygen Tension During Nonnutritive Sucking in Preterm Infants

PEDIATRICS ◽  
1984 ◽  
Vol 74 (4) ◽  
pp. 539-542
Author(s):  
Roberto Paludetto ◽  
Steven S. Robertson ◽  
Maureen Hack ◽  
Chandra R. Shivpuri ◽  
Richard J. Martin
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Preterm Infants ◽  
Oxygen Tension ◽  
Sleep State ◽  
Transcutaneous Oxygen Tension ◽  
Transcutaneous Oxygen ◽  
Beneficial Effects ◽  
Nonnutritive Sucking ◽  
Postconceptional Age

The effects of nonnutritive sucking on transcutaneous oxygen tension, heart rate, and respiratory rate were studied sequentially in 14 sleeping preterm infants breathing room air. Transcutaneous oxygen tension increased during nonnutritive sucking in infants between 32 and 35 weeks postconceptional age, but not in those between 36 and 39 weeks. This response was not associated with a change in respiratory rate or sleep state, although heart rate tended to increase. These data offer further support for the beneficial effects of nonnutritive sucking in preterm infants.

Prolonged Episodes of Hypoxemia in Preterm Infants Undetectable by Cardiorespiratory Monitors

PEDIATRICS ◽  
1995 ◽  
Vol 95 (6) ◽  
pp. 860-863 ◽  
Author(s):  
Christian F. Poets ◽  
Valerie A. Stebbens ◽  
David Richard ◽  
David P. Southall
Keyword(s):  
Heart Rate ◽  
Preterm Infants ◽  
Median Duration ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Prolonged Apnea ◽  
Gestational Age At Birth ◽  
Breathing Room ◽  
Age At Birth

Objective. To determine whether episodes of prolonged hypoxemia occur without prolonged apneic pauses (≥20 seconds) and without bradycardia (pulse rate, ≤100 beats per minute) in apparently well preterm infants. Methods. Long-term recordings of arterial oxygen saturation as measured by pulse oximetry (SpO2), photoplethysmographic (pulse) waveforms from the oximeter, and breathing movements were performed in 96 preterm infants (median gestational age at birth, 34 weeks; range, 28 to 36 weeks) who were breathing room air. Recordings started at a median age of 4 days (range, 1 to 60 days). Results. During a median duration of recording of 25 hours, 88 episodes in which SpO2 fell to 80% or less and remained there for 20 seconds or longer were identified in 15 infants. The median duration of these prolonged desaturations was 27 seconds (range, 20 to 81 seconds). In 73 episodes (83%), SpO2 continued to fall to 60% or less. Twenty-three desaturations were associated with prolonged apneic pauses and 54 with bradycardia; 19 of these were associated with both apnea and bradycardia. Thirty desaturations (34%; 10 infants) occurred without bradycardia and without prolonged apnea. Conclusions. These results indicate that a proportion of apparently well preterm infants exhibit episodes of severe prolonged hypoxemia unaccompanied by prolonged apneic pauses or bradycardia. Such episodes, therefore, would be difficult to detect if only breathing movements and heart rate are monitored. Indications for the use of oxygenation monitors in preterm infants should be reconsidered.

scholarly journals Cardiovascular changes during daily torpor in the laboratory mouse

2009 ◽  
Vol 297 (3) ◽  
pp. R769-R774 ◽  
Author(s):  
Steven J. Swoap ◽  
Margaret J. Gutilla
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Core Body Temperature ◽  
Laboratory Mouse ◽  
Caloric Intake ◽  
Peripheral Resistance ◽  
Cardiovascular Changes ◽  
Blood Pressures ◽  
Core Body ◽  
Insight Into

The laboratory mouse is a facultative daily heterotherm in that it experiences bouts of torpor under caloric restriction. Mice are the most frequently studied laboratory mammal, and often, genetically modified mice are used to investigate many physiological functions related to weight loss and caloric intake. As such, research documenting the cardiovascular changes during fasting-induced torpor in mice is warranted. In the current study, C57BL/6 mice were implanted either with EKG/temperature telemeters or blood pressure telemeters. Upon fasting and exposure to an ambient temperature (Ta) of 19°C, mice entered torpor bouts as assessed by core body temperature (Tb). Core Tb fell from 36.6 ± 0.2°C to a minimum of 25.9 ± 0.9°C during the fast, with a concomitant fall in heart rate from 607 ± 12 beats per minute (bpm) to a minimum of 158 ± 20 bpm. Below a core Tb of 31°C, heart rate fell exponentially with Tb, and the Q10 was 2.61 ± 0.18. Further, mice implanted with blood pressure telemeters exhibited similar heart rate and activity profiles as those implanted with EKG/temperature telemeters, and the fall in heart rate and core Tb during entrance into torpor was paralleled by a fall in blood pressure. The minimum systolic, mean, and diastolic blood pressures of torpid mice were 62.3 ± 10.2, 51.9 ± 9.2, 41.0 ± 7.5 mmHg, respectively. Torpid mice had a significantly lower heart rate (25–35%) than when euthermic at mean arterial pressures from 75 to 100 mmHg, suggesting that total peripheral resistance is elevated during torpor. These data provide new and significant insight into the cardiovascular adjustments that occur in torpid mice.

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