The main purpose of this study was to find out whether the dominant dorsal lung perfusion while supine changes to a dominant ventral lung perfusion while prone. Regional distribution of pulmonary blood flow was determined in 10 healthy volunteers. The subjects were studied in both prone and supine positions with ...

OBJECTIVES: To describe the nature of flow velocity waveforms from fetal middle and distal venous pulmonary branches in the second half of normal pregnancy in relation to gestation, and to test repeatability and interrelationships of flow velocity waveform recordings from proximal, middle and distal venous pulmonary branches. DESIGN: Cross-sectional study. ...

Complex congenital heart defects due to the absence of a ventricular chamber can often be treated by the Fontan surgical procedure. The objective of this work was to quantify the haemodynamics in the Fontan operation (cavopulmonary connection) with extracardiac lateral conduit. Four different models based on the finite element method ...

Turtles possess a significant postcapillary CO2 partial pressure (PCO2) disequilibrium between arterial blood and alveolar gas. There are several possible explanations for this blood disequilibrium including a slow rate of erythrocyte physiological anion shift (Cl-/HCO3- exchange) or inaccessibility of plasma HCO3- to red blood cell or pulmonary carbonic anhydrase. The ...

The purposes of this study were to quantitatively evaluate a free-breathing three-dimensional (3D) variable angle uniform signal excitation (VUSE) magnetic resonance angiography (MRA) technique in normal volunteers, to demonstrate breathold 3D VUSE MRA in a normal volunteer, and to investigate the ability of the free-breathing 3D VUSE MRA technique to ...

The purpose of this study was to investigate the rate and extent of hydroquinone (HQ) absorption and first pass metabolism in the lungs of male rats in vivo. [14C]HQ in physiological saline was administered intratracheally via an indwelling endotracheal tube to simulate inhalation exposure to HQ dust. The bioavailability of ...

RATIONALE AND OBJECTIVES: To determine and analyze the most important error sources in lung CT densitometry in vivo. METHODS: The authors examined the influences of CT acquisition errors, physiologic changes, and image segmentation errors on lung densitometry. Among others, spatial dependency and long-term reproducibility of the density measurements of blood ...

BACKGROUND: A complete understanding of fluid mechanics in Fontan physiology includes knowledge of the caval contributions to right (RPA) and left (LPA) pulmonary arterial blood flow, total systemic venous return, and relative blood flow to each lung. METHODS AND RESULTS: Ten Fontan patients underwent cine MRI. Three cine scans of ...

A thorough analysis of aerosol particle deposition in the human lung requires the knowledge of the distribution of inspired air at respiration. In this paper, a mathematical model of ventilation distribution has been developed using a five-lobe airway model. The model accounts for the nonlinear effects of compliance and resistance ...

BACKGROUND: Pulmonary xenotransplantation is not possible because of hyperacute lung injury, the pathogenesis of which is unknown. This study evaluates complement-dependent pathways of pulmonary injury during heterologous perfusion of swine lungs. METHODS: Lungs from unmodified swine and swine expressing human decay-accelerating factor and human CD59 (hDAF/hCD59 swine) were perfused with ...

Hypoxia-induced by acute lung injury results from abnormal ventilation/perfusion ratio distribution towards shunt or low ventilation/perfusion zones. Pharmacological modification of pulmonary blood flow distribution improving ventilation/perfusion ratio should correct hypoxia. The development of inhaled nitric oxide therapy had confirmed this concept, but with a relatively high proportion of 'non responders'. ...

Original studies leading to the gravitational model of pulmonary blood flow and contemporary studies showing gravity-independent perfusion differ in the recent use of laboratory animals instead of humans. We explored the distribution of pulmonary blood flow in baboons because their anatomy, serial distribution of vascular resistances, and hemodynamic responses to ...

Using end-inspiratory airway occlusion, respiratory system resistance (Rrs) can be partitioned into a flow-resistive component (Rint), and an additional component (DeltaR), reflecting viscoelasticity and time constant inequalities. We studied flow and volume dependence of Rrs and its subdivisions (Rint and DeltaR) in 13 children, seven mechanically ventilated for pulmonary insufficiency ...

The purpose of this study was to evaluate whether avoiding interruption of ventilation during surfactant instillation improves the effects on lung function and surfactant distribution and whether it prevents the adverse effects on blood pressure and cerebral blood flow. The study was performed using rabbits with severe respiratory failure induced ...

We investigated 12 anesthetized normal dogs using transesophageal echocardiography to understand the effects of respiration on the pulmonary venous flow. Additionally, we observed whether the diameter of the pulmonary vein changes with the heart beat. The pulsed Doppler wave form of pulmonary venous flow predominantly demonstrated two backward flows, with ...

Phorbol myristate acetate (PMA) activates neutrophils and causes acute lung injury. We determined the effect of ONO-5046, a specific neutrophil elastase inhibitor, on the increase in microvascular permeability induced by PMA in isolated dog lung perfused with autologous blood at a constant perfusion flow. The vascular permeability was assessed by ...

OBJECTIVE: To examine the influence of positive end-expiratory pressure (PEEP) and posture on the distribution of pulmonary blood flow. DESIGN: Experimental study. SETTING: University animal laboratory. SUBJECTS: Seven anesthetized and mechanically-ventilated lambs. INTERVENTIONS: Four conditions were studied in random order: prone or supine position, with or without 5 cm H2O ...

OBJECTIVE: Changes in pulmonary blood flow rate can alter the size of the perfused pulmonary capillary surface area. We tested the hypothesis that full recruitment of the pulmonary vascular bed may decrease evidence of lung injury by recruiting less injured capillaries. We also tested the hypothesis that endothelial ectoenzyme activity ...

A 57-year-old woman was hospitalized because of gait disturbance and dysuria. Close examination revealed a cauda equina tumor at the level of L2 and L3. Tumor resection was performed, with posterolateral fusion and spinal instrumentation. On the eleventh day after the surgery, she experienced dyspnea and chest pain during standing ...

The roles of prostaglandins and catecholamines in the hypotensive hemodynamic change during cardiopulmonary support with a venoarterial bypass (VAB) were investigated in a series of chronic animal experiments of gradually reduced pulmonary arterial blood flow (PAF). The VAB system consisted of a pulsatile ventricular assist device, an artificial lung, and ...

The different roles of bronchial and pulmonary circulation in the tracheal blood supply were investigated in 26 female rats: a control group (CG, n = 7), a group with pulmonary hilar ligation (PL, n = 5), another with tracheal transsection (TL, n = 9) and a group with both these ...

It is well known that scorpion venom induces lung lesions and respiratory distress which are usually classified as pulmonary oedema (PO). Tityus discrepans is a scorpion that lives in the north-central area of Venezuela, is the most common source of human envenomation here and produces PO. We studied the action ...

In this study, we investigated the modulatory effects of different types of blood cells on hypoxic pulmonary vasoconstrictive (HPV) response and nitric oxide (NO) release in isolated rat lungs. The lungs were perfused at a constant flow with physiologic saline solution (PSS). The changes in pulmonary arterial pressure (PAP) and ...

OBJECTIVE: To assess flow dynamics after total cavopulmonary connection (TCPC). DESIGN: Cross-sectional study. SETTING: Aarhus University Hospital. PATIENTS: Seven patients (mean age 9 (4-18) years) who had previously undergone a lateral tunnel TCPC mean 2 (0. 3-5) years earlier. INTERVENTIONS: Pressure recordings (cardiac catheterisation), flow volume, and temporal changes of ...

In mammals and birds, low oxygen levels in the lungs cause a constriction of the pulmonary vasculature. This response is locally mediated and is considered to be important for local matching of perfusion and ventilation. It is not known whether reptiles respond in a similar fashion. The present study describes ...

Surfactant nebulization improves lung function at low alveolar doses of surfactant. However, efficiency of nebulization is low, and lung deposition seems to depend on lung aeration. High frequency ventilation (HFV) has been shown to improve lung aeration. We hypothesize that the combination of HFV and surfactant nebulization may benefit lung ...

The mechanism by which pulmonary blood flow increases and pulmonary vascular resistance decreases after birth is not fully understood. The aim of this study was to simulate the decrease in lung volume caused by the onset of air-breathing at birth and determine whether it can duplicate the changes in pulmonary ...

1. Inhaled vasodilators such as nitric oxide and epoprostenol (prostaglandin I2) are now widely employed as supportive therapies to improve oxygenation and reduce pulmonary vascular resistance in patients with acute and chronic pulmonary hypertension. However, few data exist concerning their effects in normal individuals. The aim of this study was ...

In many ways, the lung is an ideal organ for study with positron emission tomography (PET). First, structure-function relations are homogeneous over larger areas than in other organs (reducing problems associated with otherwise relatively poor spatial resolution and partial-volume averaging). Second, many physiologic and metabolic processes can be studied, including ...

This article examines common cyanotic congenital heart lesions that result in an increase in pulmonary blood flow. These lesions include transposition of the great arteries, truncus arteriosus, total anomalous pulmonary venous connection, tricuspid atresia, and single ventricle. The complications caused by increased pulmonary blood flow are examined. The hemodynamics, presentation, ...

PURPOSE: It is the purpose of this study to compare pulmonary and aortic blood flow measurements obtained in patients after single lung transplantation (SLTX) with those in volunteers. METHODS/MATERIAL: In nine patients after SLTX (three male, six female) and nine volunteers (seven male, two female), double oblique phase contrast cine-MRI ...

A mathematical model of pulsatile flow in cat lung based on existing morphometric and elastic data is presented and validated by experimental results. In the model, the pulmonary arteries and veins were treated as elastic tubes, whereas the pulmonary capillaries were treated as two-dimensional sheets. The macro- and microcirculatory vasculature ...

Stop-flow studies were used to characterize solute uptake in isolated rat lungs. These lungs were perfused at 8 or 34 ml/min for 10-28 s with solutions containing 125I-albumin and two or more of the following diffusible indicators: [3H]mannitol, [14C]urea, 3HOH, 201Tl+, or 86Rb+. After this loading period, flow was stopped ...

A hypertonic sodium chloride bolus passing through the lung has a sound velocity transient that is biphasic when it reaches the carotid artery. This transient is compatible with water moving into the hypertonic bolus from the lung parenchyma, thereby leaving the lung parenchyma hypertonic. Subsequently, as the bolus leaves the ...

An infant with hypoplastic left heart syndrome, excessive pulmonary blood flow, and tachypnea was placed on subatmospheric oxygen (supplemental nitrogen) to increase pulmonary vascular resistance and decrease pulmonary blood flow. His cardiorespiratory status stabilized without mechanical ventilation, but 2 weeks later he developed spontaneous subcutaneous emphysema. The emphysema worsened over ...

We used differential excretion of sulphur hexafluoride from the left and right lung to measure blood flow diversion by hypoxic pulmonary vasoconstriction (HPV) in the prone and supine positions in dogs (n = 9). Gas exchange was assessed using the multiple inert gas elimination technique. Blood flow diversion from the ...

The transport of macromolecules through the lung interstitium depends on both bulk transport of fluid and diffusion. In the present study, we studied the diffusion of albumin. Isolated rabbit lungs were inflated with silicon rubber via airways and blood vessels, and two chambers were bonded to the sides of a ...

BACKGROUND: Recent studies have questioned the classical gravitational model of pulmonary perfusion. Because the lateral position is commonly used during surgery, the authors studied the redistribution of pulmonary blood flow in the left lateral decubitus position using a high spatial resolution technique. METHODS: Distributions of pulmonary blood flow were measured ...

OBJECTIVE: To determine how hemoglobin (Hb), platelet, and serotonin concentrations change during cardiopulmonary bypass (CPB) in sequestered blood from the pulmonary artery compared with circulating systemic blood; and to determine the correlation between platelet and serotonin variability at the two sites and clinical outcome measurements related to hemodynamics and blood ...

BACKGROUND: Previous studies have shown that availability of oxygen during lung preservation to maintain aerobic metabolism may be essential for the optimal viability of preserved lung tissue. The purpose of this study was to evaluate lung preservation with oxygenated blood for optimal oxygen delivery to the lung graft in a ...

OBJECTIVE: To evaluate the effect of Sulfo Lewis C (SO3-3âGal1-3GlcNAc-O(CH2)8-COOMe), a putative ligand of selectins, on smoke inhalation injury. DESIGN: Prospective animal study with concurrent controls. SETTING: An animal laboratory. SUBJECTS: Twelve 1-yr-old female sheep, weighing 24 to 33 kg. INTERVENTIONS: Twelve sheep received nine exposure units of smoke generated ...

Acute lung injury is a frequent clinical occurrence following blood loss and trauma. The nature of this injury remains poorly understood. OBJECTIVE: To examine the relative parenchymal and intra-alveolar distribution of inflammation in a rat model of hemorrhage and resuscitation. METHODS: Rats were anesthetized and subjected to hemorrhage followed by ...

Complete lung preservation requires the perfusate to reach the cell it intends to protect; this is directly related to the distribution of the preserving solution throughout the lung vasculature. Several prostanoids are clinically used to enhance lung preservation. We evaluated the effect of prostaglandin E2 (PGE2) on the distribution of ...

Congenital heart lesions resulting in increased pulmonary blood flow are common and if unrepaired often lead to pulmonary hypertension and heart failure. Therefore, we hypothesized that increased pulmonary blood flow without changes in pressure would result in remodeling of the pulmonary arterial wall. Furthermore, because the vasodilator nitric oxide is ...

BACKGROUND: Different modalities of cytostatic lung perfusion were compared regarding plasma and tissue drug concentrations to assess the efficacy of an endovascular blood flow occlusion technique. METHODS: A cytostatic lung perfusion study with doxorubicin hydrochloride was performed on large white pigs (n = 12). Plasma and tissue concentrations of doxorubicin ...

Inhaled nitric oxide (iNO) is a pulmonary vasodilator that recruits blood flow to well-ventilated lung areas in the presence of lung disease. iNO may improve oxygenation by decreasing intrapulmonary shunt or may worsen oxygenation by reversing hypoxic pulmonary vasoconstriction, therapy increasing ventilation-perfusion mismatch. Recent studies have examined the mechanisms for ...

Congenital heart lesions can be classified according to hemodynamic characteristics related to pulmonary blood flow patterns: increased, normal, or decreased, lesions with decreased pulmonary blood flow characteristically present with cyanosis. This article briefly reviews differential diagnoses for the presenting sign of cyanosis. Additionally, this article provides a comprehensive overview of ...

We used fluorescent-labeled microspheres in pentobarbital-anesthetized dogs to study the effects of unilateral alveolar hypoxia on the pulmonary blood flow distribution. The left lung was ventilated with inspired O2 fraction of 1.0, 0.09, or 0.03 in random order; the right lung was ventilated with inspired O2 fraction of 1.0. The ...

BACKGROUND: Recent studies have questioned the importance of the gravitational model of pulmonary perfusion. Because low levels of positive end-expiratory pressure (PEEP) are commonly used during anesthesia, the authors studied the distribution of pulmonary blood flow with low levels of PEEP using a high spatial resolution technique. They hypothesized that ...

In the clinical application of supporting circulation, the treatment of a patient with pulmonary hypertension is very important. We developed the electromagnetically driven vibrating flow pump (VFP) as a totally implantable type ventricular assist system. The artificial heart driven by electromagnetic forces creates high speed oscillation flow around 10-50 Hz. ...