Effects of Oxygen Breathing on the Heart Rate, Blood Pressure, and Cardiac Index of Normal Men—resting, With Reactive Hyperemia, and After Atropine*

Daly, Walter J.; Bondurant, Stuart

doi:10.1172/jci104454

Cited by 158 publications

(120 citation statements)

References 14 publications

(19 reference statements)

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“…Furthermore, pCO 2 , which can also affect CBV, was maintained within the normal range. We also found significant increases in MABP during NBO, which are consistent with results from a previous study in normal human volunteers that showed significant increases in both systemic resistance and brachial blood pressure (Daly and Bondurant, 1962). Changes in MABP were incorporated into the GLM model to account for this potential confound.…”

Section: Discussionsupporting

confidence: 89%

Dynamic Functional Cerebral Blood Volume Responses to Normobaric Hyperoxia in Acute Ischemic Stroke

Mandeville

et al. 2012

J Cereb Blood Flow Metab

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Studies suggest that neuroprotective effects of normobaric oxygen (NBO) therapy in acute stroke are partly mediated by hemodynamic alterations. We investigated cerebral hemodynamic effects of repeated NBO exposures. Serial magnetic resonance imaging (MRI) was performed in Wistar rats subjected to focal ischemic stroke. Normobaric oxygen-induced functional cerebral blood volume (fCBV) responses were analyzed. All rats had diffusion-weighted MRI (DWI) lesions within larger perfusion deficits, with DWI lesion expansion after 3 hours. Functional cerebral blood volume responses to NBO were spatially and temporally heterogeneous. Contralateral healthy tissue responded consistently with vasoconstriction that increased with time. No significant responses were evident in the acute DWI lesion. In hypoperfused regions surrounding the acute DWI lesion, tissue that remained viable until the end of the experiment showed relative preservation of mean fCBV at early time points, with some rats showing increased fCBV (vasodilation); however, these regions later exhibited significantly decreased fCBV (vasoconstriction). Tissue that became DWI abnormal by study-end initially showed marginal fCBV changes that later became moderate fCBV reductions. Our results suggest that a reverse-steal hemodynamic effect may occur in peripheral ischemic zones during NBO treatment of focal stroke. In addition, CBV responses to NBO challenge may have potential as an imaging marker to distinguish ischemic core from salvageable tissues.

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Section: Discussionsupporting

confidence: 89%

Dynamic Functional Cerebral Blood Volume Responses to Normobaric Hyperoxia in Acute Ischemic Stroke

Mandeville

et al. 2012

J Cereb Blood Flow Metab

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“…In normal subjects, the reduction of output is due entirely to a decrease in heart rate, since there is no accompanying reduction in stroke volume.22 23 This is apparently a reflex mechanism since it can be prevented with atropine. 22 In subjects with uncomplicated myocardial infarction there is a decrease in stroke volume as well as cardiac output.1 4 13 At the present time there is no evidence in man that arterial PO2 values in the range observed in this study exert a direct inotropic action on the heart. The possibility of a negative inotropic action of oxygen should be considered, however, because at least two reports have shown that oxygen at hyperbaric pressures exerts a direct suppressive action on myocardial contractility in experimental animals.…”

Section: Resultsmentioning

confidence: 66%

Blood-Gas and Hemodynamic Responses to Oxygen in Acute Myocardial Infarction

et al. 1973

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“…When plotting LVA against fetal tcPo 2 before and during the period of 0 2 breathing i t became obvious that LVA decreased with an increase in fetal tcPo 2 (Fig. 1).…”

Section: Resultsmentioning

confidence: 96%

“…An increase in fetal tcPo 2 i s followed by a LVA-decrease. put (2). In healty füllterm newborns 0 2 breathing results in a small decrease in HR which persists while the baby is breathing 0 2 (1).…”

Section: Resultsmentioning

confidence: 99%

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THE INFLUENCE OF MATERNAL OXYGEN (O₂) ADMINISTRATION ON FETAL HEART RATE (FHR) AND LONGTERM VARIABILITY AMPLITUDE (LVA)

Kurz¹,

Fallenstein²,

Schneider³

et al. 1982

Journal of Perinatal Medicine

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breathing in healthy adults causes a small decrease in heart rate (HR) (2). In healthy fulHerrn infants 0 2 breathing also leads to a small decrease in HR (1). When the mother is breathing pure 0 2 , a decrease of FHR and LVA in the fetus can be observed (4). These observations have been confirmed previously (5). Using an algorithm for Computer determination (CD) of FHR level and LVA (3), i t was the aim of this paper to study the behaviour of FHR and LVA before and during maternal 0 2 breathing with Computer assistance. MATERIAL AND METHODSIn 14 cases the mothers were breathing 0 2 via a face mask for about 10 min., having been instructed not.to hyperventilate and were kept in the lateral position. Recordings were made of FHR and uterine activity s well s fetal tcPo 2 . FHR and LVA were estimated visually and by using an algorithm, which makes a histogram of all FHR values. From this distribution the 10th and 90th percentile i s estimated and it's distance multiplicated with a constant factor of 1.2. The result represents the actual LVA (3). When comparing the CD FHR and LVA with the visually estimated one, a very good agreement was found (2*«0.001). RESULTSIn 11 of the 14 cases the tcPo 2 increased and FHR and LVA decreased when the mother was breathing pure 0 2 . When plotting LVA against fetal tcPo 2 before and during the period of 0 2 breathing i t became obvious that LVA decreased with an increase in fetal tcPo 2 (Fig. 1). There was a significant increase in fetal tcPo 2 by χ = 5 mmHg (2·«43.001), a significant decrease in FHR by χ = 4 bpm (2*0.05) and a significant decrease in LVA by χ = 6,7 bpm (2rf<0.001). In the other three cases the FHR remained constant whilst the LVA slightly increased during fetal tcPo 2 increase. The fetal tcPo 2 level prior to maternal 0 2 breathing was not significantly different in both groups. There was however a significant difference between the initial basal FHR level in the two groups before the onset of maternal 0 2 breathing. The mean basal FHR in the group of FHR and LVA decrease was 138 bpm compared with 126 bpm in those cases showing only an increase in" LVA (2«0.01). To draw any conclusions from the difference, the number .of cases in the second group i s too small. It might be possible that the change in activity-status was masked in some way. DISCUSSION 0 2 breathing in normal subjects causes a small decrease in HR, which is abolished by atropine and therefore probably vagal in origin, and results in a comparable rate-dependent decrease in cardiac out-0300-5577/82/0102-0037 g 2.00

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Effects of Oxygen Breathing on the Heart Rate, Blood Pressure, and Cardiac Index of Normal Men—resting, With Reactive Hyperemia, and After Atropine*

Cited by 158 publications

References 14 publications

Dynamic Functional Cerebral Blood Volume Responses to Normobaric Hyperoxia in Acute Ischemic Stroke

Dynamic Functional Cerebral Blood Volume Responses to Normobaric Hyperoxia in Acute Ischemic Stroke

Blood-Gas and Hemodynamic Responses to Oxygen in Acute Myocardial Infarction

THE INFLUENCE OF MATERNAL OXYGEN (O₂) ADMINISTRATION ON FETAL HEART RATE (FHR) AND LONGTERM VARIABILITY AMPLITUDE (LVA)

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Effects of Oxygen Breathing on the Heart Rate, Blood Pressure, and Cardiac Index of Normal Men—resting, With Reactive Hyperemia, and After Atropine*

Cited by 158 publications

References 14 publications

Dynamic Functional Cerebral Blood Volume Responses to Normobaric Hyperoxia in Acute Ischemic Stroke

Dynamic Functional Cerebral Blood Volume Responses to Normobaric Hyperoxia in Acute Ischemic Stroke

Blood-Gas and Hemodynamic Responses to Oxygen in Acute Myocardial Infarction

THE INFLUENCE OF MATERNAL OXYGEN (O2) ADMINISTRATION ON FETAL HEART RATE (FHR) AND LONGTERM VARIABILITY AMPLITUDE (LVA)

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THE INFLUENCE OF MATERNAL OXYGEN (O₂) ADMINISTRATION ON FETAL HEART RATE (FHR) AND LONGTERM VARIABILITY AMPLITUDE (LVA)