Nitric oxide and cardiopulmonary hemodynamics in Tibetan highlanders

2005 ◽  
Vol 99 (5) ◽  
pp. 1796-1801 ◽  
Author(s):  
Brian D. Hoit ◽  
Nancy D. Dalton ◽  
Serpil C. Erzurum ◽  
Daniel Laskowski ◽  
Kingman P. Strohl ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Pulmonary Artery ◽  
High Altitude ◽  
Sea Level ◽  
Pulmonary Blood Flow ◽  
Geometric Mean ◽  
Systolic Pressure ◽  
Pulmonary Artery Systolic Pressure ◽  
Exhaled No

When O2 availability is reduced unavoidably, as it is at high altitude, a potential mechanism to improve O2 delivery to tissues is an increase in blood flow. Nitric oxide (NO) regulates blood vessel diameter and can influence blood flow. This field study of intrapopulation variation at high altitude tested the hypothesis that the level of exhaled NO (a summary measure of pulmonary synthesis, consumption, and transfer from cells in the airway) is directly proportional to pulmonary, and thus systemic, blood flow. Twenty Tibetan male and 37 female healthy, nonsmoking, native residents at 4,200 m (13,900 ft), with an average O2 saturation of hemoglobin of 85%, participated in the study. The geometric mean partial pressure of NO exhaled at a flow of 17 ml/s was 23.4 nmHg, significantly lower than that of a sea-level reference group. However, the rate of NO transfer out of the airway wall was seven times higher than at sea level, which implied the potential for vasodilation of the pulmonary blood vessels. Mean pulmonary blood flow (measured by cardiac index) was 2.7 ± 0.1 (SE) l/min, and mean pulmonary artery systolic pressure was 31.4 ± 0.9 (SE) mmHg. Higher exhaled NO was associated with higher pulmonary blood flow; yet there was no associated increase in pulmonary artery systolic pressure. The results suggest that NO in the lung may play a key beneficial role in allowing Tibetans at 4,200 m to compensate for ambient hypoxia with higher pulmonary blood flow and O2 delivery without the consequences of higher pulmonary arterial pressure.

scholarly journals Progressive dysfunction of nitric oxide synthase in a lamb model of chronically increased pulmonary blood flow: a role for oxidative stress

2008 ◽  
Vol 295 (5) ◽  
pp. L756-L766 ◽  
Author(s):  
Peter E. Oishi ◽  
Dean A. Wiseman ◽  
Shruti Sharma ◽  
Sanjiv Kumar ◽  
Yali Hou ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Blood Flow ◽  
Pulmonary Artery ◽  
Pulmonary Artery Pressure ◽  
Lung Tissue ◽  
Pulmonary Blood Flow ◽  
Artery Pressure ◽  
Oxide Synthase ◽  
Inhaled No

Cardiac defects associated with increased pulmonary blood flow result in pulmonary vascular dysfunction that may relate to a decrease in bioavailable nitric oxide (NO). An 8-mm graft (shunt) was placed between the aorta and pulmonary artery in 30 late gestation fetal lambs; 27 fetal lambs underwent a sham procedure. Hemodynamic responses to ACh (1 μg/kg) and inhaled NO (40 ppm) were assessed at 2, 4, and 8 wk of age. Lung tissue nitric oxide synthase (NOS) activity, endothelial NOS (eNOS), neuronal NOS (nNOS), inducible NOS (iNOS), and heat shock protein 90 (HSP90), lung tissue and plasma nitrate and nitrite (NOx), and lung tissue superoxide anion and nitrated eNOS levels were determined. In shunted lambs, ACh decreased pulmonary artery pressure at 2 wk ( P < 0.05) but not at 4 and 8 wk. Inhaled NO decreased pulmonary artery pressure at each age ( P < 0.05). In control lambs, ACh and inhaled NO decreased pulmonary artery pressure at each age ( P < 0.05). Total NOS activity did not change from 2 to 8 wk in control lambs but increased in shunted lambs (ANOVA, P < 0.05). Conversely, NOxlevels relative to NOS activity were lower in shunted lambs than controls at 4 and 8 wk ( P < 0.05). eNOS protein levels were greater in shunted lambs than controls at 4 wk of age ( P < 0.05). Superoxide levels increased from 2 to 8 wk in control and shunted lambs (ANOVA, P < 0.05) and were greater in shunted lambs than controls at all ages ( P < 0.05). Nitrated eNOS levels were greater in shunted lambs than controls at each age ( P < 0.05). We conclude that increased pulmonary blood flow results in progressive impairment of basal and agonist-induced NOS function, in part secondary to oxidative stress that decreases bioavailable NO.

scholarly journals Brain Natriuretic Peptide and NT-proBNP Levels Reflect Pulmonary Artery Systolic Pressure in Trekkers at High Altitude

2013 ◽  
pp. 597-603 ◽  
Author(s):  
D. R. WOODS ◽  
A. MELLOR ◽  
J. BEGLEY ◽  
M. STACEY ◽  
J. O’HARA ◽  
...  
Keyword(s):  
Pulmonary Artery ◽  
Brain Natriuretic Peptide ◽  
High Altitude ◽  
Natriuretic Peptide ◽  
Natriuretic Peptides ◽  
Systolic Pressure ◽  
Pulmonary Artery Systolic Pressure ◽  
Central Feature ◽  
Post Exercise ◽  
Echocardiographic Assessment

Our objective was to evaluate the utility of the natriuretic peptides BNP (brain natriuretic peptide) and NT-proBNP as markers of pulmonary artery systolic pressure (PASP) in trekkers ascending to high altitude (HA). 20 participants had BNP and NT-proBNP assayed and simultaneous echocardiographic assessment of PASP performed during a trek to 5150 m. PASP increased significantly (p=0.006) with ascent from 24±4 to 39±11 mm Hg at 5150 m. At 5150 m those with a PASP≥40 mm Hg (n=8) (versus those with PASP<40 mm Hg) had higher post-exercise BNP (pg/ml): 54.5±36 vs. 13.4±17 (p=0.012). Their resting BNP at 5150 m was also higher: 57.3±43.4 vs. 12.6±13 (p=0.017). In those with a pathological (≥400 pg/ml) rise in NT-proBNP at 5150 m (n=4) PASP was significantly higher: 45.9±7.5 vs. 32.2±6.2 mm Hg (p=0.015). BNP and NT-proBNP may reflect elevated PASP, a central feature of high altitude pulmonary oedema, at HA.

scholarly journals Use of Almitrine and Inhaled Nitric Oxide in ARDS Due to COVID-19

2021 ◽  
Vol 8 ◽  
Author(s):  
Driss Laghlam ◽  
Ghilas Rahoual ◽  
Julien Malvy ◽  
Philippe Estagnasié ◽  
Alain Brusset ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pulmonary Artery ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Systolic Pressure ◽  
Pulmonary Artery Hypertension ◽  
Inhaled Nitric Oxide ◽  
Pulmonary Artery Systolic Pressure ◽  
Open Label ◽  
Paris Area ◽  
Fraction Of Inspired Oxygen

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is manifested by an acute respiratory distress syndrome (ARDS) with intense inflammation and endothelial dysfunction leading to particularly severe hypoxemia. We hypothesized that an impaired hypoxic pulmonary vasoconstriction aggravates hypoxemia. The objective of the study was to test the effect of two pulmonary vasoactive drugs on patient oxygenation.Methods: Observational, single-center, open-label study in one intensive care unit (ICU) of the Paris area, realized in April 2020. Eligible patients had coronavirus disease 2019 (COVID-19) and moderate to severe ARDS [arterial partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) &lt;200 mmHg] despite conventional protective ventilation. Exclusion criteria included pulmonary artery hypertension defined by a pulmonary artery systolic pressure (PAPs) &gt;45 mmHg. The assessment of oxygenation was based on PaO2/FiO2 at (1) baseline, then after (2) 30 min of inhaled nitric oxide (iNO) 10 ppm alone, then (3) 30 min combination of iNO + almitrine infusion 8 μg/kg/min, then (4) 30 min of almitrine infusion alone.Results: Among 20 patients requiring mechanical ventilation during the study period, 12 met the inclusion criteria. Baseline PaO2/FiO2 was 146 ± 48 mmHg. When iNO was combined with almitrine, PaO2/FiO2 rose to 255 ± 90 mmHg (+80 ± 49%, p = 0.005), also after almitrine alone: 238 ± 98 mmHg (+67 ± 75%, p = 0.02), but not after iNO alone: 185 ± 73 mmHg (+30 ± 5%, p = 0.49). No adverse events related to almitrine infusion or iNO was observed.Conclusion: Combining iNO and infused almitrine improved the short-term oxygenation in patients with COVID-19-related ARDS. This combination may be of interest when first-line therapies fail to restore adequate oxygenation. These findings argue for an impaired pulmonary hypoxic vasoconstriction in these patients.

Reflex stimulation of heart induced by partial occlusion of pulmonary artery

1961 ◽  
Vol 200 (3) ◽  
pp. 647-650 ◽  
Author(s):  
Alberto C. Taquini ◽  
Domingo M. Aviado
Keyword(s):  
Blood Flow ◽  
Pulmonary Artery ◽  
Pulmonary Blood Flow ◽  
Sympathetic Innervation ◽  
Systolic Pressure ◽  
Sympathetic Nerves ◽  
Partial Occlusion ◽  
Ventricular Systolic Pressure ◽  
Cardiac Stimulation ◽  
Most Probable Explanation

In anesthetized dogs, partial occlusion of the pulmonary artery causes increased pulmonary blood flow which is dependent on an intact sympathetic innervation of the heart. Neither the vagi nor the medullary centers participate in the increase in pulmonary blood flow. The most probable explanation is that the increase in pulmonary blood flow is due to reflex cardiac stimulation initiated by a rise in right ventricular systolic pressure and mediated entirely by the cardiac sympathetic nerves.

Effect of acute lower respiratory tract infection on pulmonary artery pressure in children with post-tricuspid left-to-right shunt

2021 ◽  
pp. 1-5
Author(s):  
Sakshi Sachdeva ◽  
Shyam S. Kothari ◽  
Saurabh K. Gupta ◽  
Sivasubramanian Ramakrishnan ◽  
Anita Saxena
Keyword(s):  
Tract Infection ◽  
Pulmonary Artery ◽  
Respiratory Tract ◽  
Respiratory Tract Infection ◽  
Lower Respiratory Tract Infection ◽  
Pulmonary Artery Pressure ◽  
Lower Respiratory Tract ◽  
Systolic Pressure ◽  
Pulmonary Artery Systolic Pressure ◽  
Artery Pressure

Abstract We sought to examine the influence of clinically severe lower respiratory tract infection on pulmonary artery pressure in children having CHD with post-tricuspid left-to-right shunt, as it may have physiological and clinical implications. In a prospective single-centre observational study, 45 children with post-tricuspid left-to-right shunt and clinically severe lower respiratory tract infection were evaluated during the illness and 2 weeks after its resolution. Pulmonary artery systolic pressure was estimated non-invasively using shunt gradient by echocardiography and systolic blood pressure measured non-invasively. Median pulmonary artery systolic pressure during lower respiratory tract infection was only mildly (although statistically significantly) elevated during lower respiratory tract infection [60 (42–74) versus 53 (40–73) mmHg, (p < 0.0001)]. However, clinically significant change in pulmonary artery systolic pressure defined as the increase of >10 mmHg was present in only 9 (20%) patients. In the absence of hypoxia or acidosis, only a small minority (9%, n = 4) showed significant pulmonary artery systolic pressure rise >10 mmHg. In the absence of hypoxia or acidosis, severe lower respiratory tract infection in patients with acyanotic CHD results in only mild elevation of pulmonary artery systolic pressure in most of the patients.

scholarly journals Serum-Free Thyroxine Levels Were Associated with Pulmonary Hypertension and Pulmonary Artery Systolic Pressure in Euthyroid Patients with Coronary Artery Disease

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Bingjie Wu ◽  
Jingjing Jiang ◽  
Minghui Gui ◽  
Lin Liu ◽  
Qiqige Aleteng ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Pulmonary Hypertension ◽  
Regression Analysis ◽  
Coronary Artery ◽  
Pulmonary Artery ◽  
Systolic Pressure ◽  
Free Thyroxine ◽  
Pulmonary Artery Systolic Pressure ◽  
Serum Free ◽  
Artery Disease

The aim of this study was to evaluate the association between thyroid hormone levels, pulmonary hypertension (PH), and pulmonary artery systolic pressure (PASP) in euthyroid patients with coronary artery disease (CAD). A cross-sectional study was conducted in individuals who underwent coronary angiography and were diagnosed as CAD from March 2013 to November 2013. 811 subjects (185 women and 626 men) were included in this study. PASP was measured by transthoracic Doppler echocardiography. 86 patients were diagnosed as PH and had significantly higher free thyroxine (FT4) levels than those without PH. Multiple logistic regression analysis demonstrated an independent association of FT4 levels with PH after adjustment of gender, age, body mass index, systolic blood pressure, left ventricular ejection fraction, hypertension, and medication use of calcium channel blockers, ACE inhibitors, angiotensin II receptor antagonists, and nitrates. Serum-free triiodothyronine (FT3) and thyroid-stimulating hormone (TSH) were not associated with PH. Furthermore, multivariate linear regression analysis showed that FT4 levels emerged as an independent predictor for PASP, while FT3 and TSH levels were not associated with PASP. Our study demonstrated that, in euthyroid patients with CAD, FT4 was an independent risk factor for PH, and FT4 levels were independently associated with PASP.

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