Hypoxic Pulmonary Vasoconstriction in Human Lungs

Hambraeus-Jonzon, Kristina; Bindslev, L.; Mellgård, Ase Jolin; Hedenstierna, Göran

doi:10.1097/00000542-199702000-00006

Cited by 59 publications

(36 citation statements)

References 31 publications

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“…The clinical picture varies from brady-or tachycardia to cardiogenic shock (3,4), and the transient abnormalities described include hypotension, myocardial ischemia, mitral and/or tricuspid regurgitation, and pulmonary hypertension (5,6). During the first postnatal hours, there is an inverse relationship between tricuspid velocity and age (7), and a relationship between low alveolar oxygen tension and increased pulmonary vascular resistance (8). The diagnosis of impaired myocardial function subsequent to a hypoxicischemic insult is of major importance to improve outcome in the asphyxiated neonates.…”

mentioning

confidence: 99%

Reduced Left Ventricular Function in Hypoxemic Newborn Pigs: A Strain Doppler Echocardiographic Study

Børke¹,

Edvardsen²,

Fugelseth

et al. 2006

Pediatr Res

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Myocardial dysfunction, hypotension, and increased pulmonary artery pressure are induced by asphyxia in neonates. We sought to define left ventricular (LV) systolic function by measuring longitudinal and radial contraction by strain Doppler echocardiography (SDE) in hypoxemic newborn pigs. Hypoxemia was induced in 11 anesthetized and instrumented newborn pigs by ventilation with 8% O 2 in nitrogen. When mean arterial blood pressure (BP) decreased to 15 mm Hg or arterial base excess reached Ϫ20 mmol/L or less, the pigs were reoxygenated and ventilated for 150 min. Echocardiography was performed at baseline and during hypoxemia and reoxygenation. Baseline measurements of myocardial peak systolic strain demonstrated normal longitudinal shortening and radial thickening. During hypoxemia, systolic longitudinal shortening in the mid-posterior and septal segments changed to systolic stretching. Peak strain in the mid-lateral and anterior segments decreased but without signs of paradox wall motion. Short-axis peak strain remained positive during hypoxemia, although the amplitude was reduced and delayed with respect to timing. In the newborn pig heart, we found a complex and heterogeneous systolic pattern with distinct regional differences during global hypoxemia. Rapid changes in LV function during hypoxemia and reoxygenation are assessable by SDE, and the results indicate that longitudinal systolic contraction is more vulnerable to hypoxemic changes than radial contraction. To explore the full picture of a global hypoxemic injury, both long-and short-axis functions have to be considered.

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mentioning

confidence: 99%

Reduced Left Ventricular Function in Hypoxemic Newborn Pigs: A Strain Doppler Echocardiographic Study

Børke¹,

Edvardsen²,

Fugelseth

et al. 2006

Pediatr Res

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“…It is well known that changes in FIO 2 cause hypoxic pulmonary vasoconstriction (HPV), which may result in different pulmonary gas exchange properties, likely due to varying pulmonary blood flow, and as such a different total delay time. However, previous studies investigating the effects of HPV have shown that changes in pulmonary gas exchange occur on relatively large changes in FIO 2 [19]. It is unlikely then, that pulmonary gas exchange and hence total delay time would be affected by the small changes seen here, and the pure delay time would be unaffected by changes in HPV.…”

Section: The Possible Role Of Hypoxic Pulmonary Vasoconstrictionmentioning

confidence: 52%

Measuring gas exchange with step changes in inspired oxygen: an analysis of the assumption of oxygen steady state in patients suffering from COPD

Thomsen

Weinreich

Karbing

et al. 2014

J Clin Monit Comput

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Bedside estimation of pulmonary gas exchange efficiency may be possible from step changes in FIO2 and subsequent measurement of arterial oxygenation at steady state conditions. However, a steady state may not be achieved quickly after a change in FIO2, especially in patients with lung disease such as COPD, rendering this approach cumbersome. This paper investigates whether breath by breath measurement of respiratory gas and arterial oxygen levels as FIO2 is changed can be used as a much more rapid alternative to collecting data from steady state conditions for measuring pulmonary gas exchange efficiency. Fourteen patients with COPD were studied using 4-5 step changes in FIO2 in the range of 0.15-0.35. Values of expired respiratory gas and arterial oxygenation were used to calculate and compare the parameters of a mathematical model of pulmonary gas exchange in two cases: from data at steady state; and from breath by breath data prior to achievement of a steady state. For each patient, the breath by breath data were corrected for the delay in arterial oxygen saturation changes following each change in FIO2. Calculated model parameters were shown to be similar for the two data sets, with Bland-Altman bias and limits of agreement of -0.4 and -3.0 to 2.2 % for calculation of pulmonary shunt and 0.17 and -0.47 to 0.81 kPa for alveolar to end-capillary PO2, a measure of oxygen abnormality due to shunting plus regions of low [Formula: see text] A/[Formula: see text] ratio. This study shows that steady state oxygen levels may not be necessary when estimating pulmonary gas exchange using changes in FIO2. As such this technique may be applicable in patients with lung disease such as COPD.

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“…This reduced the perfusion of the hypoxic lung from a normoxic value of 52 ± 2 to 30 ± 8% of total lung flow, without a significant fall in mixed-venous PO 2 (Hambraeus-Jonzon et al, 1997). In healthy volunteers, 8 h of hypoxia increased PVR from 1.2 ± 0.3 to 2.9 ± 0.3 Wood Units at 2 h and thereafter PVR remained constant, reversing on return to normoxia (Dorrington et al, 1997).…”

Section: Pathogenesismentioning

confidence: 92%

Hypoxic Pulmonary Arterial Hypertension in the Chicken Model

Hernández¹,

Sandino²

2011

Pulmonary Hypertension - From Bench Research to Clinical Challenges

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Hypoxic Pulmonary Vasoconstriction in Human Lungs

Abstract: A stimulus-response relation between graded hypoxia and blood flow diversion defines hypoxic pulmonary vasoconstriction in the normal human lung. Hyperoxia has no significant effect on vascular resistance in the normal human lung.

Cited by 59 publications

References 31 publications

Reduced Left Ventricular Function in Hypoxemic Newborn Pigs: A Strain Doppler Echocardiographic Study

Reduced Left Ventricular Function in Hypoxemic Newborn Pigs: A Strain Doppler Echocardiographic Study

Measuring gas exchange with step changes in inspired oxygen: an analysis of the assumption of oxygen steady state in patients suffering from COPD

Hypoxic Pulmonary Arterial Hypertension in the Chicken Model

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