We have shown previously that lateral compression of pulmonary surfactant monolayers initially induces separation of two phases but that these remix when the films become more dense (1). In the studies reported here, we used fluorescence microscopy to examine the role of the different surfactant constituents in the remixing of ...

We have compared three treatment strategies, that aim to prevent repetitive alveolar collapse, for their effect on gas exchange, lung mechanics, lung injury, protein transfer into the alveoli and surfactant system, in a model of acute lung injury. In adult rats, the lungs were ventilated mechanically with 100% oxygen and ...

1. Although abnormalities in pulmonary surfactant were initially implicated in the pathogenesis of the acute respiratory distress syndrome (ARDS) 30 years ago, most subsequent research has focused on mediators of the parenchymal acute lung injury (ALI) and the associated increase in alveolocapillary permeability. 2. Surfactant is essential for normal breathing ...

As a model of the meconium aspiration syndrome (MAS) of human infants, adult rabbits and newborn rhesus monkeys received intratracheal instillation of human meconium to induce pulmonary injury. Injured rabbits were ventilated with 100% O2 and divided into four treatment groups, receiving: 1) bronchoalveolar lavages (BAL) with dilute KL4-Surfactant; 2) ...

Although intrapulmonary fibrin deposition is a pathognomonic feature of acute lung injury, it remains uncertain whether thrombin inhibitors affect clinically important outcomes. We hypothesized that both heparin and antithrombin (AT) concentrate improve gas exchange during experimental respiratory distress syndrome. We also tested whether combination therapy is more beneficial than monotherapy. ...

BACKGROUND: It is hypothesized that surfactant treatment helps to improve severe bronchiolitis by restoring surfactant system activity. This study aims to assess the effect of surfactant on gas exchange, peak inspiratory pressure and duration of mechanical ventilation and intensive care unit (ICU) stay in children with severe bronchiolitis. METHODS: Twenty ...

The time course of histopathological changes in a rat lung lavage model of the acute respiratory distress syndrome (ARDS) was analyzed by sacrificing animals 10, 30, 60, 180, and 210 min after the last lung parenchyma lavage which was performed with physiological saline solution. This lavage depleted the lung from ...

The aim of this study was to compare the effects of modified porcine surfactant (Curosurf) given either by a simplified slow delivery technique or by the standard bolus method, on pulmonary gas exchange, lung mechanics, and surfactant distribution in rats with respiratory failure produced by lung lavage. Twelve rats with ...

OBJECTIVE: To evaluate the efficacy of treating endotoxin-induced lung injury with single dose exogenous surfactant and positive end-expiratory pressure (PEEP). DESIGN: Prospective trial. SETTING: Laboratory at a university medical center. SUBJECTS: Nineteen certified healthy pigs, weighing 15 to 20 kg. INTERVENTIONS: Pigs were anesthetized and surgically prepared for hemodynamic and ...

Pulmonary surfactant abnormalities have consistently been documented in patients with acute lung injury (ALI), however, there is little evidence directly correlating them to altered respiratory mechanics. To explore this further, surfactant composition was measured in lung aspirate fluid collected on 15 occasions from 10 patients with ALI. The composition was ...

Surfactant followed by partial liquid ventilation (PLV) with perfluorocarbon (PFC; LiquiVent) improves oxygenation, lung compliance, and lung pathology in lung-injured animals receiving conventional ventilation (CV). In this study, we hypothesize that high-frequency oscillation (HFO) and CV will provide equivalent oxygenation in lung-injured animals following surfactant repletion and PLV, once lung ...

Marked hypoxia secondary to intrapulmonary right-to-left shunting is a characteristic of respiratory failure in human neonates and can sometimes be complicated by additional extrapulmonary right-to-left shunting. To investigate the effect of inhaled nitric oxide (iNO) on intrapulmonary shunting, two typical pulmonary diseases of the newborn (respiratory distress syndrome and meconium ...

Abnormalities of premature newborn adaptation after preterm birth result in significant perinatal mortality and morbidity. We assessed the effects of short-term (24 h) fetal betamethasone exposure on preterm newborn baboon pulmonary and cardiovascular regulation and renal sodium handling during the first 24 h after birth. Male fetal baboons (Papio) (124-day ...

Measurement of mean lung volume (MLV) in high-frequency oscillatory ventilation (HFO) may be useful for optimizing the high lung volume strategy, but has not been available until now. We have measured MLV by means of the sulfur hexafluoride (SF6) washout method in 13 premature infants ventilated with HFO because of ...

Recruitment of polymorphonuclear leukocytes (PMN) through upregulation of cellular adhesion molecules is a proposed mechanism of injury in sepsis and acute respiratory distress syndrome (ARDS). We hypothesized that pretreatment of baboons with a monoclonal antibody to human E- and L-selectin (EL-246) during sepsis would decrease PMN influx into tissues and ...

In the first days of life, the daily evaporative loss from premature neonates can reach up to 20% of body mass. Such loss can be reduced by increasing the air humidity inside the incubator. Neither passive humidification nor open loop systems allow high humidity rates to be maintained or easily ...

An animal model has been used and further developed to examine and evaluate differences in regional deposition patterns of an Evans Blue dye (EB) tracer aerosol. This was done by using different carrier gas composition of either He-O2 (80% helium, 20% oxygen) or air (79% nitrogen, 21% oxygen) in histamine-provoked ...

The present study was undertaken to investigate the involvement of kinins in the cardiovascular- and respiratory effects of LQQ venom. Blood pressure, heart rate, electrocardiogram (ECG) and respiration were studied in anaesthetised rabbits, in the presence and absence of aprotinin and icatibant, a B2 bradykinin antagonist. Plasma bradykinin concentrations were ...

We studied the changes in acceleration time/right ventricular ejection time ratio (AT/RVET; indicative of changes in pulmonary artery pressure) calculated from Doppler ultrasound examinations performed before and 1, 6, and 12 h after the first and second doses of surfactant following the administration of each of three different surfactants during ...

BACKGROUND: In patients with the acute respiratory distress syndrome, pneumothorax and other air leaks - any extrusion of air outside the tracheobronchial tree - have been attributed to high ventilatory pressures or volumes and linked to increased mortality. METHODS: We analyzed data from a prospective trial of aerosolized synthetic surfactant ...

We evaluated the efficacy of a recombinant surfactant protein-C (rSP-C) surfactant in vitro and in vivo, using ventilated preterm lambs and rabbits. The surface tension measured with a Wilhelmy balance of the rSP-C surfactant was lower than the surface tension of natural sheep surfactant (containing SP-B and SP-C). The rSP-C ...

We investigated whether the style of ventilation would influence respiratory physiology or surfactant metabolism in surfactant-treated preterm lambs. Preterm lambs were delivered at 131 +/- 1 d gestation and treated with an organic solvent extract of sheep surfactant (100 mg/kg). The lambs were randomized to ventilation peiods of 2 h, ...

To investigate the effects of aspirating different meconium concentrations on the pulmonary circulation in 10- to 12-day-old piglets, 30 catheterized animals were studied. The piglets received an intratracheal bolus of 3 ml/kg of a mixture of human meconium in saline with concentrations of 20 mg/ml (light, n = 7), 40 ...

Gas ventilation following instillation of perfluorochemical (PFC) liquid, partial liquid ventilation (PLV), improves gas exchange and pulmonary mechanics in neonatal animals and humans with severe respiratory distress. The effect of PLV on cardiac contractility, performance, pulmonary blood flow and ductal shunt has not been fully described. To this end, we ...

'Rescue' surfactant treatment of premature infants with respiratory distress syndrome (RDS) results in two mechanisms: stabilization of alveoli already being ventilated and recruitment of alveoli collapsed before surfactant administration. Mechanical recruitment of alveoli from this collapsed compartment might enhance the immediate effects of surfactant treatment. To test this hypothesis 15 ...

We evaluated the effects of various ventilation strategies on the efficacy of exogenous surfactant therapy in lung-injured adult rabbits. Lung injury was induced by repetitive whole-lung saline lavage followed by mechanical ventilation. Three hours after the final lavage, 100 mg lipid/kg bovine lipid extract surfactant was instilled. After confirmation of ...

OBJECTIVE: To evaluate the role of surfactant in the mechanism and treatment of acute lung injury caused by inhalation of fabric protector. DESIGN: Prospective, randomized study. SETTING: University laboratory. INTERVENTIONS: In vitro experiment: a porcine surfactant suspension (10 mg.ml-1) was exposed to a fabric protector aerosolized with an ultrasonic nebulizer ...

AIM: To examine the effect of intravascular volume expansion for the treatment of hypovolaemia in sick preterm neonates. METHODS: An intravenous infusion of 20 ml per kg of 4.5% albumin was given to 14 preterm neonates. The effects on systolic blood pressure, central peripheral temperature difference (c-pT), and plasma arginine ...

OBJECTIVE: Case report on the effect of inhaled prostacyclin in a preterm infant (28 weeks gestational age) with respiratory distress syndrome complicated by marked hypoxemia due to persistent pulmonary hypertension of the newborn. Treatment with surfactant, hyperventilation, and elevation of systemic blood pressure had failed to improve oxygenation. MEASURES: A ...

Acute respiratory distress syndrome (ARDS) is a condition characterized by a high permeability oedema due to loss of the integrity of the alveolo-capillary barrier with impairment of normal surfactant function, resulting in an increased collapse tendency of the alveoli. Mechanical ventilation on such alveoli with repeated alveolar collapse and subsequent ...

The long-term outcome of infants with severe respiratory distress syndrome can be improved by optimizing surfactant therapy and minimizing the risk for pulmonary barovolutrauma and oxygen toxicity. The authors hypothesized that this may be achieved with low frequency ventilation and extracorporeal CO2 removal (LFV-ECCO2R), in combination with intratracheal instillation of ...

OBJECTIVES: The inhalation of nitric oxide increases oxygenation by improving the ventilation/perfusion ratios in neonates with respiratory distress syndrome and those ratios in adults with acute respiratory distress syndrome. There is evidence that inhaled nitric oxide is ineffective when the lung remains atelectatic and poorly inflated. This study aimed to ...

We compared the effects of surfactant and partial liquid ventilation (PLV), and the impact of administration order, on oxygenation, respiratory system compliance (Crs), hemodynamics, and lung pathology in an animal lung injury model. We studied four groups: surfactant alone (S; n = 8); partial liquid ventilation alone (PLV-only; n = ...

The pulsating bubble surfactometer has been commonly used to measure the minimum surface tension of lung surfactant. The complexity of the original transinterface pressure tracings and its possible physiological meanings remain undefined. In the present study, we compared surface properties between calf lung surfactant extract (CLSE) and Tween 20, a ...

The aim of this study was to determine the prolonged effects of sequential doses of a highly purified perfluorocarbon (FC 3280) on gas exchange and survival time in experimental acute respiratory distress syndrome (ARDS). The study was prospective, randomized and controlled. Twelve pigs (body weight 30 +/- 5 (mean +/- ...

We determined if surfactant treatment effect can be enhanced by mechanical volume recruitment during surfactant administration by measuring functional residual capacity, tidal volume, the alveolar portion of tidal volume, dynamic compliance of the respiratory system, a/A ratio, and PaCO2 by measuring before and after surfactant administration to rabbits with lung ...

To investigate whether nitric oxide (NO) is involved in surfactant-induced systemic and pulmonary vasodilatation in newborn piglets with surfactant deficiency, 2-6-d-old piglets were subjected to repeated saline lung lavages. They were then randomly assigned to one of two groups (seven in each group): the N(omega)-nitro-L-arginine methyl ester (L-NAME) group received ...

OBJECTIVE: Mechanical ventilation may impair cardiovascular function if the transpulmonary pressure rises. Studies on the effects of high-frequency oscillatory ventilation (HFOV) on cardiovascular functions have yielded conflicting results. This study was done to compare alterations in left ventricular output and blood flow velocities in the anterior cerebral artery, internal carotid ...

Laboratory evidence has recently confirmed clinical reports suggesting that the surfactant system is abnormal in congenital diaphragmatic hernia (CDH). Autopsy series show that, although both lungs are affected by the maldevelopment, the ipsilateral lung is more severely affected. The aim of this study was to examine the surfactant status in ...

OBJECTIVE: The objectives of this study were, to select a nebuliser first, that operates safely in a neonatal ventilator setting and, second, that is most efficient. Thirdly, we studied the particle sizes of the surfactant aerosol. Fourthly, we studied where the nebulised surfactant is deposited in the tubing system of ...

Surfactant instillation may affect systemic and pulmonary hemodynamics. The aim of this study was to investigate whether this effect is specific to surfactant or if it can be triggered by instillation of the same volume of saline. Piglets 3-5-d-old were subjected to repeated lung lavage using 20 mL/kg 0.9% saline ...

Direct intracompartmental pressure (ICP) measurement in children is an important investigation, the use of which may be inhibited by the invasive nature of the procedure and the large 18-gauge (G) needles that have hitherto been recommended. These large needles contribute to patient, parental, and physician anxiety. This study compares ICP ...

When a discocytic erythrocyte (RBC) was partially aspirated into a 1.5-microns glass pipette with a high negative aspiration pressure (delta P = -3.9 kPa), held in the pipette for 30 s (holding time, th), and then released, it underwent a discocyte-echinocyte shape transformation. The degree of shape transformation increased with ...

This study intended to evaluate the relationship between the prognosis for premature newborns (PM) with patient ductus arteriosus (PDA) and their Doppler echocardiographic findings. From January 1989 to December 1995, of 369 premature newborns in their first postnatal week, 196 underwent ductal evaluations echocardiographically: 47 of these 196 cases were ...

The influence of surfactant administration on cerebral and systemic circulation and on lung function was evaluated in 12 premature mechanically ventilated infants (mean birth weight 1,560 +/- 770 g, mean gestational age 30.0 +/- 3.2 weeks) with respiratory distress syndrome (RDS) receiving surfactant replacement therapy. We measured mean cerebral blood ...

This study was a prospective, randomized, controlled design to evaluate gas exchange, lung mechanics, and pulmonary hemodynamics during partial liquid ventilation (PLV) combined with inhaled nitric oxide (NO) in acute respiratory failure (ARF) with pulmonary hypertension (PH). ARF with PH was induced in 12 piglets weighing 9.7-13.7 kg by repeated ...

We asked if the amount of SP-B (range 37-410 micrograms/ml) in surfactants used to treat preterm lambs at 123 days of gestation correlated with postnatal lung function or the SP-B content of surfactant recovered by alveolar washes after 10 h ventilation. Ventilation was initiated using a low tidal volume strategy ...

We examined the effects of separate applications of saline and a synthetic lung surfactant preparation (Surf; Exosurf Neonatal) into the supraglottic airway (SA) on the anteroposterior pharyngeal diameter (Dap) and the airway pressures required to close (Pcl) and reopen (Pop) the SA in five awake normal supine subjects. Dap, Pcl, ...

We have compared treatment responses of two surfactants in two animal models of respiratory distress syndrome. Preterm rabbits at 27 days gestation and premature lambs at 126 days gestation were treated with natural sheep surfactant Survanta (Ross Laboratories), or no surfactant and then were ventilated with the same ventilation style ...

The aim of the present study was to evaluate the effect of hypobaric hypoxia on the changes observed within lung parenchyma, particularly in the surfactant system-forming structures. The experiment used male Wistar rats, 180-220g b.w. The animals were kept in a hypobaric chamber for 3, 10 and 30 days. Pressure ...