In anesthetized paralyzed term newborn rabbits at various postgestational ages (from birth up to 16 days), we measured by micropuncture technique the hydraulic pressure of the pulmonary interstitium (Pip), the extrapleural parietal interstitium, and the pleural liquid. Birth data refer to cesarian-delivered nonbreathing rabbits. Pip increased from 0.5 +/- 2 ...

Two human monoclonal antibodies, directed against the type a and type b flagellar proteins of Pseudomonas aeruginosa, inhibited bacterial motility in vitro specifically and in a concentration-dependent manner. In order to determine if this decreased bacterial motility was associated with a decreased pathogenicity, the ability of these human antiflagellar monoclonal ...

BACKGROUND: In southern Scandinavia most babies with respiratory distress syndrome are initially treated with nasal continuous positive airway pressure. We performed a multicenter trial to investigate whether the addition of a single dose of porcine surfactant administered during a short intubation before the occurrence of serious deterioration could reduce the ...

The effect of exogenous surfactant treatment on lung and type II cell structure of ventilated lambs of 137-138 days gestational age was studied. Thirty-four lambs were delivered and randomized to control or 100 mg/kg of natural sheep surfactant treatment groups. Lungs from one group of lambs not treated with surfactant ...

In vitro data have shown a concentration-dependent inhibition of surfactant by meconium, while anecdotal reports demonstrate improved oxygenation after surfactant replacement in babies with meconium aspiration syndrome, particularly in conjunction with high-frequency jet ventilation. We randomized 70 newborn piglets to either conventional or high-frequency jet ventilation, followed by insufflation of ...

To study the in vivo activity of the surfactant apoproteins (SP-A, SP-B, SP-C), we administered surfactants with defined apoprotein compositions to prematurely delivered rabbit pups. Rabbits given simple phospholipid mixtures containing dipalmitoylphosphatidylcholine and phosphatidylglycerol supplemented with both SP-B and SP-C or either protein alone had significantly greater lung compliance during ...

Increased phospholipase A2 activity demonstrated in some forms of lung injury may contribute to surfactant dysfunction. Phospholipase A2-resistant analogs of dipalmitoylphosphatidylcholine (DPPC) with surfactant properties might therefore be useful lipid components of treatment surfactants for certain lung injuries. The in vivo function of surfactants containing DPPC or the phospholipase-resistant analogs ...

We studied the possibility of improving lung volume and therefore clinical outcome in premature newborn lambs by increasing the inspiratory volumes during the first minute after birth. Sixteen lambs from eight were delivered by hysterotomy after 130-131 days' gestation. In eight lambs the lungs were inflated with a bag with ...

Repetitive lung lavage of adult rats leads to lung injury similar to ARDS resulting in poor gas exchange, protein leakage and infiltration of polymorphonuclear neutrophils (PMN) into the alveolar spaces (J Appl Physiol 1983; 55: 131-138). In a previous dose response comparison we have demonstrated that poor gas exchange could ...

Both ventilator pattern and neutrophil activation influence lung injury in adult respiratory distress syndrome (ARDS). We therefore questioned whether ventilator pattern independently affects neutrophil accumulation and function in early ARDS. Thirty-five New Zealand White rabbits were anesthetized, paralyzed, and prepared using sterile techniques. Fifteen surfactant-depleted animals were randomized and ventilated ...

OBJECTIVES: To test whether perfluorocarbon-associated gas exchange (gas ventilation of the perfluorocarbon-liquid filled lung) could support oxygenation better than conventional positive pressure breathing in a piglet model of gastric aspiration-induced adult respiratory distress syndrome (ARDS). DESIGN: Prospective, randomized, blinded, controlled study. SETTING: A critical care research laboratory in a university ...

Arterial-alveolar partial pressure differences for oxygen, carbon dioxide, and nitrogen were measured before and after surfactant replacement therapy on 15 occasions in 14 ventilator-dependent preterm infants with hyaline membrane disease (HMD). Eight treatments resulted in a significant improvement in arterial partial pressure of oxygen (PaO2) 2 hr after treatment; 7 ...

We studied the effect of sustained inspiratory inflations (SI) on the cardiovascular system by measuring mean central venous pressure (MCVP), mean arterial blood pressure (MABP) and heart rate (HR), before and during sustained lung inflations in premature lambs (128-133 days' gestation). SI consisted of four inflations of 5 s at ...

Previous work in our laboratory has documented alterations in surfactant composition and function after prolonged lung graft storage and transplantation in dogs (Am Rev Respir Dis 1993;148:208-15). To determine whether exogenous surfactant therapy was beneficial, we pretreated 13 canine double lung blocks with prostacyclin, flushed them with 4 degrees C ...

We designed an accurate method to study respiratory static volume-pressure relationships in small fetal and neonatal animals on the basis of Archimedes' principle. Our method eliminates the error caused by the compressibility of air (Boyle's law) and is sensitive to a volume change of as little as 1 microliters. Fetal ...

The purpose of this study was to characterize changes in the endogenous surfactant system in adult sheep rendered septic via cecal ligation and perforation (CLP). Forty-eight hours after CLP, septic animals had significant increases in mean pulmonary artery pressure (PAP) (p < 0.01), cardiac index (CI) (p < 0.01), and ...

Patients with congenital diaphragmatic hernia (CDH) have unilateral or bilateral hypoplasia of the lungs including delayed maturation of the terminal air sacs. Because these lungs are highly susceptible to barotrauma and oxygen toxicity, even in full-term newborns, continued research into optimal ventilatory regimen is essential to improve survival rate and ...

Developmental differences in the intrinsic characteristics of surfactant have not been evaluated. Therefore, heavy-subtype surfactant was recovered from alveolar washes of 132-, 139-, and 148-day preterm lambs, 2- to 3-day-old newborn ventilated lambs, and adult sheep. The density of heavy-subtype surfactant and surfactant protein-A-to-saturated phosphatidylcholine ratios increased significantly with developmental ...

OBJECTIVE: To determine the course of systolic pulmonary artery pressure (PAP) in association with ductal shunting and cardiac output (CO) in preterm neonates. DESIGN: During the acute phase of respiratory distress syndrome (RDS) with and without surfactant treatment, serial Doppler ultrasound examinations were performed at the ages of 2, 12, ...

The pathophysiology of smoke inhalation includes surfactant inhibition and pulmonary vascular injury leading to a high permeability pulmonary oedema. It has been shown in surfactant deficient animal models that methods of ventilation (i.e. high-frequency ventilation - HFV) avoiding a large pressure excursion (i.e. pressure change from end expiration to peak ...

Examination of lung washings from primitive air-breathing fishes (ropefish, bichirs, and gar) revealed a lipid-based surfactant with an average disaturated phospholipid-to-total phospholipid ratio five times lower than in mammals. The lung lavage of fishes was exceptionally rich in cholesterol, resulting in average cholesterol-to-phospholipid ratios three times higher, and cholesterol-to-disaturated phospholipid ...

Our hypothesis was that surfactant instilled into the trachea, followed by body positioning maneuvers utilized to enhance drug distribution, could alter hemodynamic function and stimulate the release of catecholamines. We conducted a prospective randomized study designed to compare the immediate physiologic effects of the first dose of Exosurf Neonatal (5 ...

Surfactant dysfunction contributes to the pathophysiology of adult respiratory distress syndrome (ARDS), and we hypothesized that surfactant treatment would improve experimental ARDS produced by continuous exposure to hyperoxia. Twelve healthy male baboons (10-15 kg) were anesthetized, paralyzed, and mechanically ventilated with 2.5 cmH2O positive end-expiratory pressure (PEEP) for 96 h. ...

BACKGROUND: It has recently been shown that large tidal volume ventilation accelerates the alveolar clearance of insoluble particles and this may be related to accelerated surfactant evacuation from the alveolus into the airway. The aim of this study was to investigate if the effect of large tidal volume ventilation is ...

We studied the effect of 3 h of large tidal volume ventilation on alveolar clearance of 0.63-micron fluorescent latex particles in rabbits during pentobarbital anesthesia. After particle deposition, six animals were killed as controls, six were subjected to large tidal volume ventilation with a peak pressure of 27 cmH2O, and ...

The aim of this study was to assess the impact of surfactant deficiency on the pathophysiology of congenital diaphragmatic hernia (CDH). Pregnant ewes were operated on at 80 days of gestation for creation of a diaphragmatic hernia in the lambs. Twenty-one lambs survived to be delivered by cesarean section and ...

Mammalian lungs secrete a mixture of surface-active lipids (surfactant), which greatly reduces the surface tension of the fluid coating the inner lung surface, thereby reducing the risk of collapse upon deflation and increasing compliance upon inflation. During foetal lung maturation, these lipids become enriched in the primary and active ingredient, ...

Immature newborn rabbits delivered at a gestational age of 27 days were tracheotomized and treated, via the tracheal cannula, with clinically recommended doses of natural or synthetic surfactant (Curosurf and Exosurf, respectively). Littermates received 0.1% tyloxapol, 5% Tween 20, or saline. The dose volume of Curosurf was 2.5 ml/kg, that ...

We previously showed that inhaling nitric oxide (NO) for up to 30 minutes selectively dilates the pulmonary circulation and improves oxygenation in newborn lambs with persistent pulmonary hypertension. In the current study we determined whether inhaling NO for 23 hours increased the survival rate of newborn lambs with persistent pulmonary ...

In a placebo-controlled study, the characteristics and duration of action of a commercially available bovine lung surfactant factor (LSF; 50 mg/kg body weight) were investigated in premature lambs at 124-127 days gestational age. Exact mating of ewes was controlled by progesterone hormone analysis. To minimize unwanted effects of narcotics through ...

BACKGROUND AND OBJECTIVE: Surfactant replacement is a powerful therapy for newborns with respiratory distress syndrome, but limited observations suggest that alterations of cerebral blood flow can accompany the use of several available surfactants. An early European multicenter controlled study with beractant demonstrated an increased rate of intracranial hemorrhage in treated ...

Surfactant therapy and high-frequency oscillatory ventilation (HFO) may minimize damage to the pulmonary epithelium of surfactant-deficient newborns. Using pulmonary clearance of insufflated, aerosolized 99mTc-DTPA (molecular weight 492) as an index of lung epithelial permeability, we examined the effects of 300 mg bovine lipid extract surfactant (S) administered at birth to ...

We previously showed that the lung of the central Australian lizard, Ctenophorus nuchalis, contains a large amount of surfactant, the composition of which varies with body temperature. We now show that the specific compliance of the lungs of these lizards remains constant regardless of whether they were maintained at 10, ...

Pulmonary surfactant deactivation is an important factor in the pathophysiology caused by wood smoke inhalation. Surfactant replacement is beneficial in treatment of surfactant-deficient neonates and possibly the adult respiratory distress syndrome (ARDS). In this study, the effect of exogenous Exosurf treatment for acute wood smoke injury was examined in four ...

To test the hypothesis that lowering the concentrations of surfactant molecules at the gas-liquid interface increases viscoelastic dissipation in the lungs, the amplitude and time course of stress relaxation were quantified before and after lavage of the lungs with warm saline in five newborn and five 8-wk-old anesthetized piglets. Stress ...

We evaluated four ventilator patterns after the administration of 80 mg/kg bovine lipid extract surfactant (LES) to anesthetized, paralyzed, saline-lavaged New Zealand white rabbits. Two ventilator types were compared: high frequency oscillatory ventilation (HFO) versus conventional mechanical ventilation (CMV), each at high (HI) and low (LO) end-expiratory lung volumes (EELV); ...

A recent multicenter study of preterm infants concluded that high-frequency ventilation (HFV) applied at 15 Hz, in comparison with conventional mechanical ventilation (CMV), did not lead to reduced incidence of barotrauma, contrary to previous expectations. The primary goal of the present theoretical study was to determine whether computed estimates of ...

In order to evaluate further the physiological and inflammatory changes of meconium aspiration syndrome (MAS), 25 newborn piglets (1-2 days old, 1.5 +/- 0.4 kg) were studied. Piglets were briefly ventilated with 100% oxygen and then received an intratracheal bolus of 3 mL/kg of a 20% suspension of human meconium. ...

Local transendoscopic endobronchial antigen challenge, which has proved to be a valuable clinical and research technique in the study of human pulmonary hypersensitivity, was evaluated in control and asymptomatic COPD--affected horses. Transendoscopic endobronchial challenges with phosphate-buffered saline (PBS), Micropolyspora faeni extract at 60 and 600 micrograms/ml and mouldy hay extract ...

To evaluate the acute effects of surfactant replacement therapy on pulmonary circulation in neonatal respiratory distress syndrome, we studied 25 infants before and for 1 hour after either synthetic surfactant administration (n = 15) or endotracheal suctioning (n = 10). The noninvasive Doppler method was used to estimate systolic pulmonary ...

Sepsis may cause pulmonary dysfunction and altered metabolism; triiodothyronine (T3) replacement improves lung function and surfactant pool. We evaluated the biophysical effects of T3 replacement during sepsis-induced hypothyroidism. Male Holtzman rats underwent cecal ligation and puncture (CLP) or sham laparotomy (S); treatment was administered consisting of T3 (3 ng/h) or ...

The sometimes limited effect of surfactant therapy in neonates might be explained in part by an non homogeneous distribution of the surfactant after endotracheal instillation. This distribution can be improved significantly by increasing the fluid volume. The aim of this study was to evaluate the effect of two methods for ...

OBJECTIVE: To determine to what extent the reduced risk in preterm newborns of intracranial hemorrhage attributed to antenatal corticosteroids (ANCS) reflects reductions in the incidence of respiratory distress and its correlates. METHODS: In a sample of 239 very low birth weight newborns recruited for a clinical trial of phenobarbital prophylaxis ...

OBJECTIVE: To study the immediate effects of exogenous surfactant therapy on blood gases, lung volumes, and lung mechanics in adult rabbits with experimentally induced respiratory distress syndrome. DESIGN: Prospective randomized, controlled study. SETTING: Laboratory and animal facility of a large university. SUBJECTS: Twelve adult New Zealand white rabbits. INTERVENTIONS: Respiratory ...

Blood pressure was retrospectively studied in all 22 extremely low birth weight infants (ELBW) (birth weight median 720 g, range 450-1020 g) who were admitted between July 1989 and October 1991 and received dexamethasone on days 2-25 (median 10) because of bronchopulmonary dysplasia or since lung function had not improved ...

Surfactant administration causes a rapid and dramatic improvement in gas exchange, but paradoxically, studies have failed to show an improvement in the mechanical properties of the lung. We have measured dynamic and static (passive flow-volume technique) compliance before and after a single dose of bovine lipid extract surfactant in 22 ...

The purpose of this study was to analyze the impact of neonatal care practices on the efficacy of exogenous human surfactant. Two hundred newborns (gestational age 24.0 to 29.9 weeks, lecithin-sphingomyelin ratio less than 2 or absent phosphatidylglycerol, and requirement of mechanical ventilation at birth) participated in a randomized bicenter ...

During pressure- or volume-controlled ventilation different surfactant preparations were compared in an improved rabbit fetus model. Based on a self-designed software program, this model enables on-line registration of lung mechanics and heart rate in up to ten fetuses. Using a commercially available bovine lung surfactant (SURVANTA) as standard, we compared ...

Adult sheep (35 +/- 3 kg) underwent saline lung lavage and 1.5 h of mechanical ventilation to induce acute lung injury. Animals received 100 mg lipid/kg body wt of tracheally instilled surfactant (Inst Surf) or either nebulized surfactant (Neb Surf) or nebulized saline (Neb Saline) and were killed 3 h ...

The in vivo function of surfactants reconstituted using natural surfactant lipid and protein constituents was evaluated in 27-day-gestation preterm rabbits. The animals were treated with protein-free surfactant lipids (LH-20), LH-20 + 5% SP-A, LH-20 + 1% SP-B, LH-20 + 1% SP-C, LH-20 + 5% SP-A + 1% SP-B + 1% ...