Cardiovascular response to arousal from sleep under controlled conditions of central and peripheral chemoreceptor stimulation in humans

2004 ◽  
Vol 96 (3) ◽  
pp. 865-870 ◽  
Author(s):  
Denise M. O'Driscoll ◽  
Guy E. Meadows ◽  
Douglas R. Corfield ◽  
Anita K. Simonds ◽  
Mary J. Morrell

The cardiovascular response to an arousal occurring at the termination of an obstructive apnea is almost double that to a spontaneous arousal. We investigated the hypothesis that central plus peripheral chemoreceptor stimulation, induced by hypercapnic hypoxia (HH), augments the cardiovascular response to arousal from sleep. Auditory-induced arousals during normoxia and HH (>10-s duration) were analyzed in 13 healthy men [age 24 ± 1 (SE) yr]. Subjects breathed on a respiratory circuit that held arterial blood gases constant, despite the increased ventilation associated with arousal. Arousals were associated with a significant increase in mean arterial blood pressure at 5 s ( P < 0.001) and with a significant decrease in the R-R interval at 3 s ( P < 0.001); however, the magnitude of the changes was not significantly different during normoxia compared with HH (mean arterial blood pressure: normoxia, 91 ± 4 to 106 ± 4 mmHg; HH, 91 ± 4 to 109 ± 5 mmHg; P = 0.32; R-R interval: normoxia, 1.12 ± 0.04 to 1.02 ± 0.05 s; HH, 1.09 ± 0.05 to 0.92 ± 0.04 s; P = 0.78). Mean ventilation increased significantly at the second breath postarousal for both conditions ( P < 0.001), but the increase was not significantly different between the two conditions (normoxia, 5.35 ± 0.40 to 9.57 ± 1.69 l/min; HH, 8.57 ± 0.63 to 11.98 ± 0.70 l/min; P = 0.71). We conclude that combined central and peripheral chemoreceptor stimulation with the use of HH does not interact with the autonomic outflow associated with arousal from sleep to augment the cardiovascular response.

1980 ◽  
Vol 48 (2) ◽  
pp. 362-369 ◽  
Author(s):  
S. Lahiri ◽  
T. Nishino ◽  
E. Mulligan ◽  
A. Mokashi

Discharges from aortic and carotid body chemoreceptor afferents were simultaneously recorded in 18 anesthetized cats to test the hypothesis that aortic chemoreceptors, because of their proximity to the heart, respond to changes in arterial blood gases before carotid chemoreceptors. We found that carotid chemoreceptor responses to the onset of hypoxia and hypercapnia, and to the intravenously administered excitatory drugs (cyanide, nicotine, and doxapram), preceded those of aortic chemoreceptors. Postulating that this unexpected result was due to differences in microcirculation and mass transport, we also investigated their relative speed of responses to changes in arterial blood pressure. The aortic chemoreceptors responded to decreases in arterial blood pressure before the carotid chemoreceptors, supporting the idea that the aortic body has microcirculatory impediments not generally present in the carotid body. These findings strengthened the concept that carotid bodies are more suited for monitoring blood gas changes due to respiration, whereas aortic bodies are for monitoring circulation.


1986 ◽  
Vol 61 (1) ◽  
pp. 271-279 ◽  
Author(s):  
C. L. Stebbins ◽  
J. C. Longhurst

We examined the contribution of bradykinin to the reflex hemodynamic response evoked by static contraction of the hindlimb of anesthetized cats. During electrical stimulation of ventral roots L7 and S1, we compared the cardiovascular responses to hindlimb contraction before and after the following interventions: inhibition of converting enzyme (kininase II) with captopril (3–4 mg/kg, n = 6); inhibition of kallikrein activity with aprotinin (Trasylol, 20,000–30,000 KIU/kg, n = 8); and injection of carboxypeptidase B (500–750 U/kg, n = 7). Treatment with captopril augmented the rise in mean arterial blood pressure and maximal time derivative of pressure (dP/dt) caused by static contraction from 21 +/- 3 to 39 +/- 7 mmHg and 1,405 +/- 362 to 2,285 +/- 564 mmHg/s, respectively. Aprotinin attenuated the contraction-induced rise in mean arterial blood pressure (28 +/- 4 to 9 +/- 2 mmHg) and maximal dP/dt (1,284 +/- 261 to 469 +/- 158 mmHg/s). Carboxypeptidase B reduced the cardiovascular response to static contraction. Thus the mean arterial blood pressure response was decreased from 36 +/- 12 to 24 +/- 11 mmHg, maximal dP/dt from 1,618 +/- 652 to 957 +/- 392 mmHg/s, and heart rate from 12 +/- 2 to 7 +/- 1 beats/min. These data suggest that stimulation of muscle afferents by bradykinin contributes to a portion of the reflex cardiovascular response to static contraction.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Sean D Stocker

Compelling evidence indicates increased cererbrospinal fluid (CSF) sodium elevates sympathetic nerve activity (SNA) and arterial blood pressure (ABP) in salt-sensitive hypertension. RVLM neurons project to the spinal cord and regulate SNA and ABP under a number of physiological challenges and pathophysiological states. Therefore, we hypothesized that RVLM neurons mediate the sympathoexcitatory response to increased CSF sodium. Inactin-anesthetized, male Sprague-Dawley rats (n=5/group) were prepared for sympathetic nerve recordings and a lateral ventricle brain cannula. Infusion of 1M NaCl (5 μL/10 min) to increase CSF sodium concentrations by 5mM produced a significant (P’s<0.05, n=6) increase in lumbar SNA (Δ: 115±3%), adrenal SNA (Δ: 122±3%), and mean arterial blood pressure (Δ: 8±1 mmHg). The infusion did not affect splanchnic SNA (Δ: 102±4%) but decreased renal SNA (Δ: 91±2%). Inhibition of the RVLM with bilateral injection of the GABA agonist muscimol (2.5mM per 50 nL per side) significantly (P’s<0.05; n=5) attenuated the increased lumbar SNA (Δ:101±2%), adrenal SNA (Δ:105±2%), and mean arterial blood pressure (Δ: 1±1mmHg, P’s<0.05; n=6). Blockade of ionotropic glutamate receptors in the RVLM with bilateral injection of kynurenic acid (30mM per 50 nL per side) also significantly (P’s<0.05; n=5) attenuated the increase in lumbar SNA (Δ: 101±3%), adrenal SNA (Δ: 110±3%) and mean ABP (Δ: 1±2 mmHg) to lateral ventricle infusion of 1M NaCl (5uL/10 min). In a final set of experiments, in vivo single-unit recordings demonstrate that ventricular infusion of 1M NaCl (5uL per 10 min) increased discharge in 60% (6/10) of spinally-projecting, barosensitive RVLM neurons (2.1±0.4 to 5.8±0.2 Hz, P<0.05). Infusion of artificial CSF did not affect any variable. These findings suggest increased CSF sodium activates a glutamatergic pathway to RVLM neurons to elevate SNA and ABP.


Author(s):  
Yiannis Papachatzakis ◽  
Pantelis Theodoros Nikolaidis ◽  
Sofoklis Kontogiannis ◽  
Georgia Trakada

High-flow oxygen through nasal cannula (HFNC) provides adequate oxygenation and can be an alternative to noninvasive ventilation (NIV) for patients with hypoxemic respiratory failure. The aim of the present study was to assess the efficacy of HFNC versus NIV in hypercapnic respiratory failure. Patients (n = 40) who were admitted to the Emergency Department of Alexandra Hospital due to hypercapnic respiratory failure (PaCO2 ≥ 45 mmHg) were randomized assigned into two groups, i.e., an intervention group (use of HFNC, n = 20) and a control group (use of NIV, n = 20). During their hospitalization in the Intensive Care Unit, vital signs (respiratory and heart rate, arterial blood pressure) and arterial blood gases (ABG) were closely monitored on admission, after 24 h and at discharge. No difference between the two groups regarding the duration of hospitalization and the use of HFNC or NIV was observed (p > 0.05). On admission, the two groups did not differ in terms of gender, age, body mass index, APACHE score, predicted death rate, heart rate, arterial blood pressure and arterial blood gases (p > 0.05). Respiratory rate in the HFNC group was lower than in the NIV group (p = 0.023). At discharge, partial carbon dioxide arterial pressure (PaCO2) in the HFNC group was lower than in the NIV group (50.8 ± 9.4 mmHg versus 59.6 ± 13.9 mmHg, p = 0.024). The lowerPaCO2 in the HFNC group than in the NIV group indicated that HFNC was superior to NIV in the management of hypercapnic respiratory failure.


2020 ◽  
Vol 27 (07) ◽  
pp. 1470-1475
Author(s):  
Mohsin Riaz Askri ◽  
Shumyala Maqbool ◽  
Kausar Abbas Shah ◽  
Shahbaz Ahmad

Objectives: To determine the role of 800 mg oral gabapentin in attenuating cardiovascular response to laryngoscopy and tracheal intubation. Study Design: Double Blind Randomized Control Trial. Setting: Independent University Hospital/Independent Medical College, Faisalabad, Pakistan. Period: Six months from January1st 2019 to June 30th 2019. Material & Methods: This study included 60 patients which were divided into two equal groups. 800 mg oral gabapentin was given to group I while capsule placebo was administrated to group II patients in pre-operative area one hour prior to surgery. Heart rate, systolic, diastolic and mean arterial blood pressure were taken after induction of anesthesia at base line and then 1,2,3,4,5,10 and 15 minutes after endotracheal intubation. SPSS version 11 was used to analyze the data. Heart rate systolic, diastolic and mean arterial blood pressure were dependent variables while placebo and gabapentin were independent variables. Results: Out of total 60 patients there were 36 (60 %) males and 24 (40 %) females. In group I mean age was 37.1 while in group II it was 36.3. As compare to group II there was decreased cardiovascular response in group I. There was a significant decrease in systolic blood pressure at 1,2 and 10 minutes; diastolic blood pressure at 3 minutes; heart rate at 10 and 15 minutes and mean arterial blood pressure at 3 minutes after induction in group I. Conclusion: Cardiovascular response to laryngoscopy and intubation is significantly reduced with oral gabapentin.


1986 ◽  
Vol 251 (1) ◽  
pp. R82-R90 ◽  
Author(s):  
J. W. Hubbard ◽  
R. H. Cox ◽  
B. J. Sanders ◽  
J. E. Lawler

Normotensive Wistar-Kyoto (WKY) rats and borderline hypertensive rats (BHR) were exposed to aversive classical conditioning procedures and chronically instrumented with arterial catheters and electromagnetic flow probes around the ascending aorta. After postoperative recovery, hemodynamic measurements and blood samples were obtained from conscious animals at rest and during aversive conditioning. The cardiovascular response to the behavioral stress consisted of a significant increase in mean arterial blood pressure, total peripheral resistance index, cardiac index, heart rate, and aortic dP/dt for both strains. However, the elevated vascular resistance seen in the BHR resulted in a significantly greater increase in mean arterial blood pressure (21 mmHg) compared with the WKY rats (14 mmHg). In addition, the BHR showed a significantly (P less than 0.05) greater plasma norepinephrine concentration (760 +/- 99 pg/ml) in response to the stress than did the WKY rats (559 +/- 53 pg/ml). These data suggest that an increase in cardiac output, elevated vascular resistance, and increased sympathetic drive may contribute to the development of stress-induced hypertension in this animal model.


2005 ◽  
Vol 98 (4) ◽  
pp. 1349-1355 ◽  
Author(s):  
Denise M. O'Driscoll ◽  
Konstantinos Kostikas ◽  
Anita K. Simonds ◽  
Mary J. Morrell

The cardiovascular response to an arousal from sleep at the termination of an obstructive apnea is more than double that to a spontaneous arousal. We investigated the hypothesis that stimulation of respiratory mechanoreceptors, by inspiring against an occluded airway during an arousal from sleep, augments the accompanying cardiovascular response. Arousals (>10 s) from stage 2 sleep were induced by a 1-s auditory tone (85 dB) during a concomitant 1-s inspiratory occlusion (O) and without an occlusion [i.e., control arousal (C)] in 15 healthy men (mean ± SE: age, 25 ± 1 yr). Arousals were associated with a significant increase in mean arterial blood pressure (MAP) at 4 s ( P < 0.001) and a significant decrease in R-R interval at 3 s ( P < 0.001). However, the magnitude of the cardiovascular response was not different during C compared with O (MAP: C, 86 ± 3 to 104 ± 3 mmHg; O, 86 ± 3 to 105 ± 3 mmHg; P = 0.99. R-R interval: C, 1.12 ± 0.03 to 0.89 ± 0.04 s; O, 1.11 ± 0.02 to 0.87 ± 0.02 s, P = 0.99). Ventilation significantly increased during arousals under both conditions at the second breath ( P < 0.001); this increase was not different between the two conditions (C: 4.40 ± 0.29 to 6.76 ± 0.61 l/min, O: 4.35 ± 0.34 to 7.65 ± 0.73 l/min; P = 0.31). We conclude that stimulation of the respiratory mechanoreceptors by transient upper airway occlusion is unlikely to interact with the arousal-related autonomic outflow to augment the cardiovascular response in healthy young men.


2015 ◽  
Vol 309 (10) ◽  
pp. R1273-R1284 ◽  
Author(s):  
Jennifer Magnusson ◽  
Kevin J. Cummings

The role of serotonin (5-HT) neurons in cardiovascular responses to acute intermittent hypoxia (AIH) has not been studied in the neonatal period. We hypothesized that a partial loss of 5-HT neurons would reduce arterial blood pressure (BP) at rest, increase the fall in BP during hypoxia, and reduce the long-term facilitation of breathing (vLTF) and BP following AIH. We exposed 2-wk-old, 5,7-dihydroxytryptamine-treated and controls to AIH (10% O2; n = 13 control, 14 treated), acute intermittent hypercapnia (5% CO2; n = 12 and 11), or acute intermittent hypercapnic hypoxia (AIHH; 10% O2, 5% CO2; n = 15 and 17). We gave five 5-min challenges of AIH and acute intermittent hypercapnia, and twenty ∼20-s challenges of AIHH to mimic sleep apnea. Systolic BP (sBP), diastolic BP, mean arterial pressure, heart rate (HR), ventilation (V̇e), and metabolic rate (V̇o2) were continuously monitored. 5,7-Dihydroxytryptamine induced an ∼35% loss of 5-HT neurons from the medullary raphe. Compared with controls, pups deficient in 5-HT neurons had reduced resting sBP (∼6 mmHg), mean arterial pressure (∼5 mmHg), and HR (56 beats/min), and experienced a reduced drop in BP during hypoxia. AIHH induced vLTF in both groups, reflected in increased V̇e and V̇e/V̇o2, and decreased arterial Pco2. The sBP of pups deficient in 5-HT neurons, but not controls, was increased 1 h following AIHH. Our data suggest that a relatively small loss of 5-HT neurons compromises resting BP and HR, but has no influence on ventilatory plasticity induced by AIHH. AIHH may be useful for reversing cardiorespiratory defects related to partial 5-HT system dysfunction.


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