Aestivation of the African Lungfish Protopterus Aethiopicus: Cardiovascular and Respiratory Functions

1974 ◽  
Vol 61 (1) ◽  
pp. 111-128 ◽  
Author(s):  
R. G. DELANEY ◽  
S. LAHIRI ◽  
A. P. FISHMAN
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Respiratory Function ◽  
Control Range ◽  
Arterial Blood ◽  
Arterial Ph ◽  
Sensory Disturbances ◽  
The Mean ◽  
African Lungfish

The present study was undertaken to elicit the temporal sequence of changes in cardiovascular and respiratory function during aestivation. Twelve lungfish (2-6 kg) equipped with ECG electrodes, arterial and buccal cannulae, were studied while aestivating in mud or in artificial cloth-bag nests. The periods of observation ranged from 0.5 to 9.5 months. The mean arterial blood pressure gradually decreased from control values of 20-28 mm Hg to a range of 14-18 mmHg during the first 30 days of aestivation, whereas the heart rate dropped more gradually (22-30 beats/min to 11-16 beats/min in 6o days). Ventilatory frequency increased 2- to 5-fold during the first 30 days of encystment and then returned to the control range (2-10 h) within 45 days. The arterial PCOCO2 increased from control values of 25-30 mm Hg to 45-70 mmHg; arterial pH decreased concomitantly from 7.55-7.60 to 7.40-7.26 after the cocoon was formed. The arterial POO2 increased from the control range of 25-40 to 50-58 mmHg during the first 10 days and then returned to the control range. Therefore, the sequential cardiopulmonary changes during the onset of aestivation are gradual and do not parallel the decline in oxygen consumption. Aestivating lungfish also respond promptly to sensory disturbances and thus do not appear to be in a deep torpor. Aestivation is pictured as a state of dormancy, gradual in onset, and the consequence of a complicated physiological interplay.

Reduced parasympathetic control of heart rate in obese dogs

1995 ◽  
Vol 269 (2) ◽  
pp. H629-H637 ◽  
Author(s):  
B. N. Van Vliet ◽  
J. E. Hall ◽  
H. L. Mizelle ◽  
J. P. Montani ◽  
M. J. Smith
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rate Control ◽  
Saturated Fat ◽  
Pressure Control ◽  
Resting Heart Rate ◽  
Arterial Blood ◽  
Parasympathetic Control ◽  
The Mean ◽  
Affect Heart Rate

We investigated why resting heart rate is elevated in dogs fed a high saturated fat diet for 12.7 +/- 1.8 wk. Obese dogs exhibited elevated body weight (59%), blood pressure (14%), and heart rate (25%). Differences in resting heart rate (control, 58 +/- 5 beats/min; obese, 83 +/- 7 beats/min) were abolished after hexamethonium, indicating an autonomic mechanism. Hexamethonium also reduced blood pressure in obese (20 +/- 4 mmHg) but not control (9 +/- 6 mmHg) animals. Propranolol did not affect heart rate in either group, excluding a beta-adrenergic mechanism. Subsequent administration of atropine increased heart rate more in control than in obese dogs (110 +/- 9 vs. 57 +/- 11 beats/min). The sensitivity of the cardiac limb of the baroreflex (Oxford method) was reduced by 46% in the obese group, confirming impairment of the parasympathetic control of heart rate. The standard deviation of blood pressure measurements was normal when expressed as a percentage of the mean arterial blood pressure (control, 11.2 +/- 0.4%; obese, 11.2 +/- 0.5%). Our results indicate that the development of obesity in dogs fed a high saturated fat diet is accompanied by an attenuated resting and reflex parasympathetic control of heart rate.

Physical training and heart rate and blood pressure variability: a 5-yr randomized trial

2004 ◽  
Vol 286 (5) ◽  
pp. H1821-H1826 ◽  
Author(s):  
Arja L. T. Uusitalo ◽  
Tomi Laitinen ◽  
Sari B. Väisänen ◽  
Esko Länsimies ◽  
Rainer Rauramaa
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Blood Pressure Variability ◽  
Maximal Oxygen Consumption ◽  
Final Analysis ◽  
Peak Performance ◽  
Autonomic Modulation ◽  
The Mean ◽  
Time Point

We studied the effect of regular physical activity on cardiac and vascular autonomic modulation during a 5-yr controlled randomized training intervention in a representative sample of older Finnish men. Heart rate variability (HRV) and blood pressure variability (BPV) are markers of cardiac and vascular health, reflecting cardiac and vascular autonomic modulation. One hundred and forty randomly selected 53- to 63-yr-old men were randomized into two identical groups: an intervention (EX) group and a reference (CO) group, of which 89 men remained until the final analysis (EX: n = 47; CO: n = 42). The EX group trained for 30–60 min three to five times a week with an intensity of 40–60% of maximal oxygen consumption. The mean weekly energy expenditure of the training program for the 5-yr training period was 3.80 MJ, and 71% of the EX group exceeded the mean. The EX group had a significantly ( P < 0.01) higher oxygen consumption at ventilatory aerobic threshold (V̇o2VT) than the CO group at the 5-yr time point. V̇o2VT had a tendency to increase in the EX group and decrease in the CO group (interaction P < 0.001) from the baseline to the 5-yr time point. Peak performance did not change. Low-frequency power of R-R interval variability decreased in the EX group ( P < 0.01, by 6%) from the baseline to the 5-yr time point. BPV did not change. In conclusion, low-intensity regular exercise training did not prevent HRV from decreasing or change BPV in 5 yr in older Finnish men.

scholarly journals Effect of adding dexmedetomidine or remifentanil to thiopental in patients with mood disorder candidate for electroconvulsive therapy

2020 ◽  
pp. 1-6
Author(s):  
Faezeh Heidarbeigi ◽  
Hamidreza Jamilian ◽  
Anita Alaghemand ◽  
Alireza Kamali
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mood Disorders ◽  
Electroconvulsive Therapy ◽  
Recovery Time ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Significant Difference ◽  
The Mean ◽  
Remifentanil Group

Electroconvulsive therapy (ECT) is one of the appropriate treatments for many neuropsychiatric patients, especially those with mood disorders. Short-term complications of ECT include agitation and postictal. In this study, we compared the addition of dexmedetomidine or remifentanil to thiopental as the main anaesthetic used in ECT. In this double-blind randomised clinical trial, 90 patients with mood disorders (candidates for ECT) were divided into two groups based on their therapy: dexmedetomidine or remifentanil. In the first group (DG), patients were slowly injected intravenously with 0.5 μg/kg dexmedetomidine before induction of anesthesia. In the second group (GR), 100 μg of remifentanil was slowly injected intravenously.In addition, we collected demographic information such as respiratory rate, heart pulse rate, seizure time, mean of arterial blood pressure, recovery duration and the oxygen arterial saturation recorded after recovery. Data obtained were analysed by use of statistical software, SPSS-23. The mean age of both groups was approximately 37 years with the majority being men. There was no significant difference between the two groups in terms of age and sex, blood pressure, heart rate, duration of seizures and arterial oxygen saturation before ECT. The mean blood pressure and heart rate in the recovery group were lower in the dexmedetomidine group than in the remifentanil group and the hemodynamics in the dexmedetomidine group were more stable. The recovery time in the dexmedetomidine group was longer than that of the remifentanil group (p = 0.001). Both groups had approximately the same satisfaction and the rate of agitation after ECT was the same. Both remifentanil and dexmedetomidine as adjuvants lead to a decrease in patients' post-ECT hyperdynamic responses. In our study, we demonstrated that the effect of dexmedetomidine is greater than remifentanil. On the other hand, neither dexmedetomidine nor remifentanil had a negative effect on seizure duration, but dexmedetomidine significantly prolonged recovery time, when compared to remifentanil.

Pulmonary effects of acute prenatal asphyxia in ventilated premature lambs

1988 ◽  
Vol 65 (1) ◽  
pp. 26-33 ◽  
Author(s):  
D. Berry ◽  
A. Jobe ◽  
M. Ikegami ◽  
S. Seidner ◽  
A. Pettenazzo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Animal Model ◽  
Dry Weight ◽  
Bronchial Obstruction ◽  
Balloon Catheters ◽  
Arterial Blood ◽  
Arterial Ph ◽  
The Mean ◽  
Pool Sizes ◽  
Prenatal Asphyxia

The effect of profound repetitive prenatal asphyxial insults on the cardiopulmonary function of premature ventilated lambs was studied. Twenty-nine fetal lambs (approximately 138 days gestational age) were exteriorized. In 16 of these lambs, the umbilical cord was occluded for 4 min then released for 10 min. This asphyxial episode was repeated until the arterial pH was approximately 7.00, and the mean arterial blood pressure was less than 40 mmHg and falling. The 13 control lambs were simply exteriorized with the umbilical circulation intact. The lambs were then ventilated for 3-4 h. There were no differences between the control vs. asphyxiated lambs in pulmonary compliances (0.57 and 0.58 ml.cmH2O-1.kg-1) wet-to-dry weight ratios (8.18 and 7.55), cardiac outputs (177.8 and 141.8 ml.kg-1.min-1), surfactant-saturated phosphatidylcholine pool sizes, or atrial and/or ductal shunts. Asphyxia did not interfere with the redirection of blood away from atelectatic lung segments created by bronchial obstruction with balloon catheters. Also, although the bidirectional flux of protein into and out of the airways of these preterm lambs was large relative to term lambs, there was no effect of asphyxia on this protein leak. In this animal model, prenatal asphyxia did not impact negatively on the severity of the respiratory failure.

Effects of GABA receptor blockage on the respiratory response to hypoxia in sedated newborn piglets

1994 ◽  
Vol 77 (2) ◽  
pp. 1006-1010 ◽  
Author(s):  
J. Huang ◽  
C. Suguihara ◽  
D. Hehre ◽  
J. Lin ◽  
E. Bancalari
Keyword(s):  
Blood Pressure ◽  
Central Nervous System ◽  
Heart Rate ◽  
Nervous System ◽  
Oxygen Consumption ◽  
Ventilatory Response ◽  
Receptor Blocker ◽  
Newborn Piglets ◽  
Arterial Blood ◽  
Ventilatory Response To Hypoxia

Brain gamma-aminobutyric acid (GABA) levels increase during hypoxia, which may modulate the ventilatory response to hypoxia. To test the possibility that the depressed neonatal ventilatory response to hypoxia may be related to increased central nervous system GABA activity, 26 sedated spontaneously breathing newborn piglets (age 5 +/- 1 day, wt 1.7 +/- 0.4 kg) were studied. Minute ventilation (VE), oxygen consumption, heart rate, arterial blood pressure, and arterial blood gases were measured in room air and after 1, 5, and 10 min of hypoxia (inspired O2 fraction 0.10) before drug intervention. Immediately after these measurements, an infusion of saline or the GABA alpha-receptor blocker (bicuculline, 0.3 mg/kg iv) or beta-receptor blocker (CGP-35348, 100–300 mg/kg iv) was administered while animals were hypoxic. All measurements were repeated at 1, 5, and 10 min after initiation of the drug infusion. Basal VE was similar among groups. During hypoxia, VE increased significantly in the animals that received either a GABA alpha- or beta-receptor blocker but not in those receiving saline. Changes in arterial Po2, oxygen consumption, heart rate, and arterial blood pressure were similar among groups before and after saline or GABA antagonist infusion. These results suggest that the decrease in ventilation during the biphasic ventilatory response to hypoxia in the neonatal piglet is in part mediated through the depressant effect of GABA on the central nervous system.

scholarly journals Effect of adding dexmedetomidine or remifentanil to thiopental in patients with mood disorder candidate for electroconvulsive therapy

2020 ◽  
Vol 30 (3) ◽  
Author(s):  
Faezeh Heidarbeigi ◽  
Hamidreza Jamilian ◽  
Anita Alaghemand ◽  
Alireza Kamali
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mood Disorders ◽  
Electroconvulsive Therapy ◽  
Recovery Time ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Significant Difference ◽  
The Mean ◽  
Remifentanil Group

Electroconvulsive therapy (ECT) is one of the appropriate treatments for many neuropsychiatric patients, especially those with mood disorders. Short-term complications of ECT include agitation and postictal. In this study, we compared the addition of dexmedetomidine or remifentanil to thiopental as the main anaesthetic used in ECT. In this double-blind randomised clinical trial, 90 patients with mood disorders (candidates for ECT) were divided into two groups based on their therapy: dexmedetomidine or remifentanil. In the first group (DG), patients were slowly injected intravenously with 0.5 μg/kg dexmedetomidine before induction of anesthesia. In the second group (GR), 100 μg of remifentanil was slowly injected intravenously.In addition, we collected demographic information such as respiratory rate, heart pulse rate, seizure time, mean of arterial blood pressure, recovery duration and the oxygen arterial saturation recorded after recovery. Data obtained were analysed by use of statistical software, SPSS-23. The mean age of both groups was approximately 37 years with the majority being men. There was no significant difference between the two groups in terms of age and sex, blood pressure, heart rate, duration of seizures and arterial oxygen saturation before ECT. The mean blood pressure and heart rate in the recovery group were lower in the dexmedetomidine group than in the remifentanil group and the hemodynamics in the dexmedetomidine group were more stable. The recovery time in the dexmedetomidine group was longer than that of the remifentanil group (p = 0.001). Both groups had approximately the same satisfaction and the rate of agitation after ECT was the same. Both remifentanil and dexmedetomidine as adjuvants lead to a decrease in patients' post-ECT hyperdynamic responses. In our study, we demonstrated that the effect of dexmedetomidine is greater than remifentanil. On the other hand, neither dexmedetomidine nor remifentanil had a negative effect on seizure duration, but dexmedetomidine significantly prolonged recovery time, when compared to remifentanil.

scholarly journals The COMPARISON BETWEEN HYPERBARIC BUPIVACAINE PLUS FENTANYL AND HYPERBARIC BUPIVACAINE ALONE IN SPINAL ANESTHESIA FOR CAESAREAN SECTION

2021 ◽  
Vol 71 (3) ◽  
pp. 1033-36
Author(s):  
Fatima Iqbal ◽  
Manzoor Ahmed Faridi ◽  
Aisha Saeed ◽  
Inamullah Shah
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Caesarean Section ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Control Group ◽  
Study Group ◽  
Hyperbaric Bupivacaine ◽  
Arterial Blood ◽  
The Mean

Objective: To compare the result of the combination of hyperbaric bupivacaine plus fentanyl with hyperbaric bupivacaine alone in patients undergoing caesarean section in spinal anaesthesia. Study Design: Comparative, cross-sectional study. Place and Duration of Study: Department of Anesthesia, Fauji Foundation Hospital, Rawalpindi Pakistan, from Dec 2017 to Jun 2018. Methodology: After consulting the institutional ethical review committees a total of 60 females between ages 18-40 years were enrolled for caesarean section delivery. They were divided into two groups. The study group (n=30) received a subarachnoid injection of 0.5% hyperbaric bupivacaine (10mg) 2ml with 25ug of fentanyl 0.5ml and control group (n=30) was injected 0.5% hyperbaric bupivacaine 12.5mg (2.5 ml) only. Pain experienced during the procedure was assessed by using 10-point visual analogue scoring method. The mean duration of analgesia, mean arterial blood pressure and heart rate after surgery were compared between two groups. Results: The mean duration of analgesia was 206.5/min ± 6.4 in the study group and it was 163.6min ± 7.2 in the control group (p=0.001). Mean arterial BP after surgery was 92.3mmHg ± 3.8 in the study group and 88.7mmHg ± 4.1 in the control group (p=0.001). The mean heart rate recorded after surgery was 75.2/min ± 5.2 in the study group and it was 70.4/min ± 6.1 in the control group (p=0.001). Conclusions: The mean duration of analgesia was significantly longer in the study group when compared with the control group with better mean arterial blood pressure and heart rate response after Caesarean section.

Circulatory and respiratory effects of whole-body vibration in anesthetized dogs

1965 ◽  
Vol 20 (6) ◽  
pp. 1157-1162 ◽  
Author(s):  
William B. Hood ◽  
Lawrence S. Higgins
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Whole Body Vibration ◽  
Vibration Response ◽  
Whole Body ◽  
Sinusoidal Vibration ◽  
Body Vibration ◽  
Arterial Blood ◽  
Anesthetized Dogs

Effects of whole body x-axis sinusoidal vibration were studied in 27 anesthetized dogs. At a vibratory frequency of 10 cycles/sec and at levels of peak acceleration greater than 0.3 g, increases in the accelerative force of vibration were accompanied by increases in mean arterial blood pressure, heart rate, cardiac output, oxygen consumption, central blood volume, and minute volume of ventilation. Peripheral vascular resistance decreased under the same conditions. At 6 cycles/sec similar results were obtained, the only significant differences being in blood pressure and heart rate response. In three animals curare partially blocked the increase in oxygen consumption during vibration. Reserpine had no effect in two other animals. These studies suggest that the circulatory responses observed during whole-body vibration are due to muscular exercise. vibration physiology; acceleration physiology; biomechanics; vibration and exercise; curare and vibration response; reserpine and vibration response Submitted on February 1, 1965

Baroreflexive depression of oxygen consumption in the squirrel monkey at 10 degrees C

1977 ◽  
Vol 232 (5) ◽  
pp. H451-H458 ◽  
Author(s):  
N. Wasserstrum ◽  
J. A. Herd
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Rectal Temperature ◽  
Cold Exposure ◽  
Squirrel Monkeys ◽  
Inhibitory Effects ◽  
Arterial Blood ◽  
Total Body ◽  
Total Body Oxygen

Unanesthetized squirrel monkeys exposed to an ambient temperature of 10 degrees C showed elevations in total body oxygen consumption (VO2), arterial blood pressure (BP), and heart rate (HR) above values recorded at 28 degrees C. Further elevation of BP in the cold by intravenous infusion of phenylephrine was accompanied by immediate reduction in VO2, inhibition of shivering, and decrease in rectal temperature, as well as immediate reduction in HR. The magnitude of reduction in VO2 correlated with the magnitude of the concomitant baroreflexive bradycardia. When the pressor effects of phenylephrine were opposed by administration of diazoxide or phentolamine, the inhibitory effects of phenylephrine on both HR and VO2 were abolished. In animals previously subjected to bilateral sinoaortic denervation, both the bradycardia and depression in oxygen consumption normally associated with BP elevation were markedly reduced. These results suggest that elevation of blood pressuere can inhibit the thermoregulatory increase in total body oxygen consumption normally produced by cold exposure, and that this inhibition, like the concomitant bradycardia, is probably mediated via the sinoaortic baroreceptors.

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