Inhibitory effects of CO2 on airway defensive reflexes in enflurane-anesthetized humans

1989 ◽  
Vol 66 (6) ◽  
pp. 2642-2646 ◽  
Author(s):  
T. Nishino ◽  
K. Hiraga ◽  
Y. Honda
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Water Injection ◽  
Inhibitory Effects ◽  
Tracheal Mucosa ◽  
Ventilatory Drive ◽  
Enflurane Anesthesia ◽  
Spontaneously Breathing ◽  
Airway Irritation ◽  
Respiratory Responses

We investigated responses of respiration, blood pressure, and heart rate to tracheal mucosa irritation induced by injection of distilled water at three different levels of CO2 ventilatory drive in 11 spontaneously breathing female patients under a constant depth of enflurane anesthesia [1.1 minimum alveolar concentration (MAC)]. The airway irritation at the resting level of spontaneous breathing caused a variety of respiratory responses such as coughing, expiration reflex, apnea, and spasmodic panting, with considerable increases in blood pressure and heart rate. Although the latency of respiratory responses after water injection was much shorter than those of blood pressure and heart rate responses, blood pressure and heart rate responses, once elicited, were prolonged much longer than was the respiratory response. An increase in CO2 ventilatory drive decreased the degree and duration of respiratory, blood pressure, and heart rate responses to the airway irritation, whereas a decrease in CO2 ventilatory drive had the opposite effect on these responses. Our results indicate that changes in CO2 ventilatory drive can modify reflex responses of respiration, blood pressure, and heart rate to airway irritation.

Mechanism of circulatory responses to systemic hypoxia in the anesthetized dog

1965 ◽  
Vol 209 (2) ◽  
pp. 397-403 ◽  
Author(s):  
Hermes A. Kontos ◽  
H. Page Mauck ◽  
David W. Richardson ◽  
John L. Patterson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Vascular Resistance ◽  
The Other ◽  
Arterial Flow ◽  
Arterial Blood ◽  
Systemic Hypoxia ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing

The possibility that mechanisms secondary to the increased ventilation may contribute significantly to the circulatory responses to systemic hypoxia was explored in anesthetized dogs. In 14 spontaneously breathing dogs systemic hypoxia induced by breathing 7.5% oxygen in nitrogen increased cardiac output, heart rate, mean arterial blood pressure, and femoral arterial flow, and decreased systemic and hindlimb vascular resistances. In 14 dogs whose ventilation was kept constant by means of a respirator pump and intravenous decamethonium, systemic hypoxia did not change cardiac output, femoral arterial flow, or limb vascular resistance; it significantly decreased heart rate and significantly increased systemic vascular resistance. In seven spontaneously breathing dogs arterial blood pCO2 was maintained at the resting level during systemic hypoxia. The increase in heart rate was significantly less pronounced but the other circulatory findings were not different from those found during hypocapnic hypoxia. Thus, mechanisms secondary to increased ventilation contribute significantly to the circulatory responses to systemic hypoxia. Hypocapnia accounts partly for the increased heart rate, but not for the other circulatory responses.

scholarly journals The effect of ketamine and saffan on the b-endorphin and ACTH response to hemorrhage in the minipig

2009 ◽  
pp. 799-805
Author(s):  
T Ruane-O’Hora ◽  
WJ Hall ◽  
F Markos
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Physiological Response ◽  
Adrenocorticotrophic Hormone ◽  
Stress Hormone ◽  
Hormone Response ◽  
Endocrine Response ◽  
Anesthetic Agents ◽  
Group I ◽  
Spontaneously Breathing

The endocrine response is an important component of the physiological response to blood loss. There is some variability in reported levels of certain hormones during hemorrhage such as the stress hormone adrenocorticotrophic hormone (ACTH). Therefore, the effect of two anesthetic agents, ketamine and saffan, on ACTH and β-endorphin levels during hemorrhage was assessed in 12 minipigs. The animals were divided into two groups, group I saffan and group II ketamine (n=6). Pigs were subjected to a continuous fixed volume hemorrhage under one of the above anesthetics while spontaneously breathing. Blood pressure and heart rate responses were recorded together with β-endorphin and ACTH levels both before and at 10, 20, 30, 40 min after the onset of bleeding. ACTH levels were higher in the ketamine-anesthetized pigs and rose significantly faster with falling blood pressure than ACTH measured in pigs under saffan anesthesia. In contrast, the hemorrhage induced β-endorphin increase was not significantly different between the two anesthetic groups. These results indicate that choice of anesthetic agent is important when investigating the hormone response to hemorrhage and may account for the variable hormone levels in the published literature to date.

Respiratory and cardiovascular alterations during the process of anoxic death in the newborn

1960 ◽  
Vol 15 (2) ◽  
pp. 249-252 ◽  
Author(s):  
S. Cassin ◽  
H. G. Swann ◽  
B. Cassin
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Respiratory Failure ◽  
Circulatory System ◽  
Systematic Investigation ◽  
Circulatory Failure ◽  
Hypoxic Conditions ◽  
Considerable Individual Variation ◽  
Respiratory Responses ◽  
Newborn Animals

A systematic investigation was conducted during the process of anoxic death in newborn pups, rabbits and kittens less than 24 hr. old. Simultaneous measurements of respiration, heart rate and blood pressure were made. Considerable individual variation in the respiratory responses of newborn animals breathing nitrogen was noted. Under hypoxic conditions, respiratory failure may follow circulatory failure in the adult, whereas in the newborn, respiratory failure always occurred long before circulatory failure. The effect of anoxia on the cardiovascular system of the newborn at the time of the last breath was not as pronounced as might have been anticipated. Great individual differences with respect to blood pressure and heart rate throughout the period of anoxia were noted. The systolic blood pressure, on the average, was seen initially to fall more rapidly than the diastolic blood pressure or heart rate; it then slowly tapered off. The circulatory system was noted to function, although at hypotensive levels, for long periods of anoxia. Submitted on June 29, 1959

The Effects of Glycopyrrolate-Pyridostigmine Mixture on Heart Rate and Blood Pressure during Halothane and Enflurane Anesthesia

1988 ◽  
Vol 21 (3) ◽  
pp. 428 ◽  
Author(s):  
Jin Hyung Kwon ◽  
Kyoung Hun Kim ◽  
Dong Ho Lee ◽  
Kyo Sang Kim ◽  
Jung Kook Suh ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Enflurane Anesthesia

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.

Phenyl biguanide does not inhibit locomotion in conscious rabbits

1995 ◽  
Vol 79 (4) ◽  
pp. 1346-1350 ◽  
Author(s):  
K. P. O'Hagan ◽  
R. S. Anderson ◽  
L. B. Bell ◽  
S. W. Mittelstadt ◽  
P. S. Clifford
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
New Zealand ◽  
Saline Infusion ◽  
C Fibers ◽  
New Zealand White Rabbits ◽  
Saline Vehicle ◽  
Cardiac Receptors ◽  
Respiratory Responses ◽  
Stimulation Of

Stimulation of cardiopulmonary vagal C fibers with phenyl biguanide (PBG) reflexly inhibits locomotion in addition to causing depression of blood pressure (BP), heart rate (HR), and respiration in cats and rats. We investigated whether PBG caused somatomotor inhibition during exercise in the rabbit, a species in which it is known that the hemodynamic and respiratory responses to PBG are mediated by cardiac rather than by pulmonary receptors. In eight New Zealand White rabbits, BP, HR, and hindlimb electromyographic (EMG) responses to 60 and 120 micrograms/kg PBG and saline vehicle were evaluated during two separate 3-min exercise bouts at 10 m/min at 0% grade. During exercise, 60 micrograms/kg PBG decreased BP (-27 +/- 4 mmHg) and HR (-95 +/- 16 beats/min) but did not inhibit locomotion as suggested by the EMG response (+112 +/- 8% of preinfusion EMG). Hemodynamic and EMG responses to 120 micrograms/kg PBG were similar to 60 micrograms/kg PBG. Saline infusion during exercise had no effect on HR, BP, or locomotion (+114 +/- 8% of preinfusion EMG). Locomotion is not inhibited by PBG in rabbits, which suggests that PBG-induced reflex somatomotor inhibition observed in other species is primarily mediated by pulmonary rather than by cardiac receptors.

scholarly journals Cardio-respiratory responses to standardized load resistance training in recreationally active participants

2015 ◽  
Vol 4 ◽  
Author(s):  
Nur Ikhwan Mohamad
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Resistance Training ◽  
Energy Expenditure ◽  
Metabolic Cost ◽  
Exercise Protocol ◽  
Blood Pressure Monitor ◽  
Pressure Monitor ◽  
Metabolic System ◽  
Respiratory Responses

<p>This paper aims to determine acute responses of standardized resistance training load on cardio-respiratory variables in recreationally active participants. The methodology involved twelve recreationally active males with an age of 23.5 (± 4.07) years, a mass of 70.5 (± 7.84 kg), a height of 1.69 (± 0.06 m), and a body mass index of 24.8 (± 2.14) kg/m<sup>2</sup>). The participants performed an exercise protocol that comprises five exercises on a standardized load. Each exercise was performed in a duration of 60 seconds with uncontrolled lifting velocity. Cardio-respiratory responses were measured using a portable metabolic system analyzer during the exercises. A wrist digital blood pressure monitor was used to determine pre- and post-protocol blood pressure responses. Based on the results, pre- and post-protocol systolic (p=0.744) and diastolic (p=0.758) blood pressure indicated no significant responses. However, significant differences were observed in pre- and post-heart rate responses (p=0.000). Peak cardio-respiratory responses recorded during the protocol were 30.2 (± 4.02) ml/Kg/min for oxygen consumption, 138 (± 61.9) bpm for heart rate, and 633 (± 71.2) kcal for energy expenditure (estimated per hour). On average, the Metabolic Equivalent of Task (MET) was recorded at a value of 8.62 (± 1.19). For a short duration standardized load circuit training exercise protocol, cardio respiratory responses were similar to other protocols. The metabolic cost of the predefined exercises was nearly half of the recommended energy expenditure through exercise per week. The prescribed protocol was comparable with other exercise protocols for cardiorespiratory variables. The single set protocol used was efficient in terms of caloric expenditure, and was less strenuous over similar exercise duration. Furthermore, the prescribed protocol is applicable and beneficial for active and healthy individuals.</p>

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