OBJECTIVES: To study the individual and combined effects of surfactant inactivation and mechanical ventilation on pulmonary microvascular permeability and lung compliance. DESIGN: Prospective, controlled trial. An isolated, perfused, lung model of surfactant inactivation and mechanical ventilation at 15, 30, and 45 cm H2O peak inspiratory pressure was developed in young ...

Four pulmonary surfactant preparations (natural sheep surfactant, Exosurf, Infasurf, and Survanta) were compared with no treatment in 29 newborn lambs at 126 +/- 1 days gestation. Fetuses were delivered by Cesarean section under general anesthesia and treated with either the manufacturer's recommended dose of a commercial surfactant, 100 mg phospholipid/kg ...

The short-term distribution kinetics of exogenous surfactant distribution after intratracheal instillation was investigated in surfactant-deficient neonatal piglets during assisted conventional mechanical ventilation and by high-frequency jet ventilation using exogenous calf lung surfactant extract (CLSE) labeled with 99mTc. Surfactant deficiency was induced by repeated bronchoalveolar lavage in piglets (1.2 +/- 0.4 ...

During surfactant treatment of respiratory distress syndrome, 23 premature newborns were investigated with continuous amplitude-integrated electroencephalography (cerebral function monitors). Simultaneously, arterial blood pressure and transcutaneous blood gas values were recorded. A short (less than 10 minutes) but significant decrease in cerebral activity was seen in almost all neonates immediately after ...

We measured clearance of 99mTc-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA) in rabbits with experimentally increased alveolar surfactant content. In one group of animals, surfactant production was increased by treatment with ambroxol, and another group of animals was treated with tracheal instillation of natural surfactant. A group of untreated control animals and ...

The high mortality for congenital diaphragmatic hernia (CDH) has been attributed to a combination of pulmonary hypoplasia and pulmonary hypertension. We hypothesize that a surfactant deficiency may in part be contributing to the pathophysiology of CDH. This study documents the functional, quantitative, and qualitative aspects of the surfactant status of ...

Following maternal treatments with 50 mg/kg/day ambroxol for 2 or 3 days before delivery at 28 days gestation, preterm rabbits were ventilated to evaluate lung function. Subsequently, surfactant saturated phosphatidylcholine (SatPC) pool sizes were measured. One half of the ambroxol treated and control rabbits were given surfactant at delivery. Although ...

Preliminary measurements of functional residual capacity (FRC) with the sulphurhexafluoride technique and static pressure volume diagrams were performed in newborn infants with respiratory distress syndrome receiving endotracheal instillation of natural porcine surfactant (Curosurf, 100 or 200 mg/kg). Within the first hour after surfactant treatment there was an increase in FRC ...

There is a wide variability in the therapeutic responsiveness to exogenous surfactant, a drug that has become generally available for the treatment of lung immaturity and respiratory distress syndrome. Recent studies have demonstrated evidence that therapies decreasing lung edema improve the effectiveness of surfactant substitution. In addition, exogenous surfactant may ...

Gas mixtures containing oxygen and nitrogen or dense inert gases (sulfur hexafluoride, SF6, or argon, Ar) were inhaled by anaesthetized, artificially ventilated rabbits and cats. SF6 and Ar were compared to nitrous oxide (N2O), a dense inert gas well known for its anaesthetic properties. Concentrations in these gases were 50% ...

Theophylline (p less than 0.05) and ketotifen (p greater than 0.05) markedly reduced, but the lipoxygenase inhibitors and PAF receptor antagonists were without any influence on the endothelin-1 (ET-1 1 nmol/kg i.v.) induced increase of pulmonary inflation pressure of anaesthetised and ventilated guinea-pigs. The ET-1 induced increase in mean arterial ...

Three days after subcutaneous injection of N-nitroso-N-methylurethane (NNNMU) to induce lung injury, adult rabbits were mechanically ventilated and lung function was evaluated. Each animal then received either nebulized Survanta (Neb Surv), nebulized saline (Neb Saline), nebulized gas alone (Neb Gas), or tracheally instilled Survanta (Inst Surv). The ventilation efficiency index ...

Asthmatic subjects were challenged with aerosols of hyper- and hypotonic saline 15 min (Group A) and 90 min (Group B) after inhaling clemastine. Measurements were made of forced expiratory volume in one second (FEV1) before and after medication and after challenge. When the FEV1 values (% predicted) were compared on ...

To determine whether changes in lung volume may be responsible for the clinical improvement in preterm infants given exogenous surfactant, we measured functional residual capacity (FRC), lung mechanics, and partial pressure of oxygen in seven ventilated neonates (birth weight 1080 +/- 361 gm (mean +/- SD); gestational age 28.3 +/- ...

Prophylactic treatment with ovine surfactant was evaluated in preterm lambs at risk for development of hyaline membrane disease. Eight mechanically ventilated newborn lambs were treated before delivery and 10 served as controls (gestational age 129-131 d). Lung mechanics, functional residual capacity, alveolar ventilation, efficiency of ventilation, and distribution of ventilation ...

A containment laboratory unit for research with aerosols of group 2 pathogenic microorganisms is described. The design criteria are based on current UK guidelines, which imply containment at group 3 level during aerosol production, storage, exposure of animals and sampling. Within the aerosol laboratory, primary containment is provided by a ...

Few studies have been done to establish the ventilatory factors affecting alveolar surfactant under resting conditions. Experiments in which ventilatory variables were recorded for 4 h were performed in 12 adult cats breathing spontaneously under pentobarbital sodium anesthesia. After the animals were killed and bronchoalveolar lavages (BALs) were performed, the ...

It has been suggested that high frequency oscillatory ventilation (HFV) might improve gas exchange and reduce the risk of pressure-related side-effects compared to conventional mechanical ventilation (CMV). Whereas most studies have used arbitrarily set frequencies for HFV, we evaluated the effects of HFV near resonant frequency (fr). Anaesthetised and tracheotomized ...

The effect of intratracheal surfactant administration was studied in rats with adult respiratory distress syndrome associated with infection with nebulized Sendai virus. Thirty-six hours after infection, animals (n = 7) showed severely impaired gas exchange and acidosis during artificial ventilation (PaO2 = 152.2 +/- 18.7, PaCO2 = 65.3 +/- 19.2, ...

High-frequency oscillatory ventilation (HFOV) permits adequate gas exchange but avoids the large phasic pressure-volume excursions of conventional mechanical ventilation (CMV); such avoidance may reduce the lung injury associated with hyaline membrane disease (HMD). We hypothesized that premature monkeys ventilated from birth with HFOV would have reduced lung injury compared to ...

Modified natural porcine surfactant was mixed with edema fluid sampled from the airways of hyperoxia-exposed adult rabbits. By varying the concentration of surfactant lipids (10, 25, and 50 mg/mL) and edema fluid proteins (0-280 mg/mL), we obtained a series of preparations with protein to surfactant lipid weight ratios ranging from ...

We applied a new ventilator-multi-plethysmograph system to evaluate the effect of surfactant replacement in newborn rabbits under well controlled, nearly physiological conditions characterized by normal ECG and adequate PCO2 in right ventricular heart blood obtained at the end of the experiment. Up to 10 animals were ventilated in parallel with ...

The reactivities of neonatal and adult microcirculation have been studied and compared. The cutaneous reactive hyperemia after 1 and 4 min of arterial occlusion (AO) was measured with a laser-Doppler fluxmeter in 21 healthy neonates and 10 adults. Local skin temperature, mean arterial blood pressure (MAP), and skin prick hematocrit ...

We investigated whether alveolar surface force increased and participated in the lung pressure-volume relationship in bleomycin-induced pulmonary fibrosis in hamsters and, if so, whether lung surfactant was hampered in the lungs. On the air-filled pressure-volume curve, decreases of lung volume from control level were significantly higher at 3-8 cmH2O pressure ...

Volume and deformability of blood cells are important determinants of the microcirculation. Leukocytes are larger and considerably less deformable than erythrocytes. In our study, volume and deformability of polymorphonuclear neutrophils (PMN), lymphocytes, and monocytes in adults and full-term neonates were studied by means of a micropipette system. Neonatal immature granulocytes ...

We studied the hemodynamic consequences during the first 24 h of life in premature baboons (140 d) with hyaline membrane disease that were treated with high-frequency oscillatory ventilation (HFOV) or conventional intermittent mandatory ventilation (IMV). Cardiac output and organ blood flow were measured at three time-points using the radiolabeled microsphere ...

To evaluate the potential for aerosolized surfactant treatments of surfactant deficiency, twin lamb fetuses were delivered at 130-132 days gestational age and received nebulized natural surfactant (Neb NS), nebulized Survanta (Neb Surv), tracheally instilled natural surfactant (Inst NS), or nebulized saline (Neb Saline). Neb NS and Neb Surv groups had ...

Substitution of surfactant in immature lungs has two functional targets: the reduction of the overall alveolar surface tension and the mechanical stabilization of the system of alveoli having different diameters. Indeed, the lowering of the surface tension facilitates the inflation of the lungs, but according to Laplace's law small and ...

The adult respiratory distress syndrome is a major cause of morbidity and mortality in critical care patients. Lung injury in this syndrome is frequently associated with lung infection. The combined insults result in an influx of neutrophils and damage to the pulmonary epithelium. We investigated whether active neutrophil elastolytic activity ...

Adult rabbit lung surfactant was radioactively labelled with [3H]palmitate and isolated by centrifugation. This material was instilled into the trachea of fetal rabbits prematurely delivered on the 27th gestational day. A similar preparation of unlabelled surfactant was used to measure the effects on pressure-volume characteristics in lungs of 27th day ...

In order to differentiate the effects of hyperoxia and barotrauma in the pathogenesis of acute neonatal lung injury, piglets were either hyperventilated (Paco2, 15-20 torr) for 48 hours with 100% oxygen (Group I), hyperventilated with 21% oxygen (Group II), normally ventilated (Paco2, 40-45 torr) with 100% oxygen (Group III), or ...

We tested the hypothesis that surfactant replacement would be beneficial in the acid-aspiration model of acute lung injury. HCl (0.1 N, 2 ml/kg) was injected into the trachea of excised rabbit lungs (n = 8). Control lungs (n = 4) had no intervention. All were perfused with Tyrode's solution mixed ...

Surfactant protein-A (SP-A) isolated from cow surfactant was added to organic solvent extracts of natural bovine surfactant or of Survanta (Abbott Laboratories), and dynamic compliances and pressure-volume curves were measured in rabbits with a gestational age of 27 days. Organic solvent extracts of natural surfactant and Survanta significantly improved dynamic ...

To determine whether acute fatty acid lung injury impairs pulmonary surfactant function, we studied anesthetized ventilated rabbits given oleic acid (55 mg/kg iv, n = 11) or an equivalent volume of saline (n = 8). Measurements of pulmonary mechanics indicated a decrease in dynamic compliance within 5 min of injury ...

The effect of high alveolar surface tension on alveolar epithelial permeability was studied in anesthetized closed-chest mongrel dogs. Alveolar surface tension was elevated by displacement of pulmonary surfactant from the alveolar hypophase by the aerosolized detergent dioctyl sodium sulfosuccinate (OT). After measurement of baseline hemodynamics, arterial blood gases, and airway ...

Surfactant isolated from adult rabbits was separated into large aggregate forms (LA) and small aggregate forms (SA) by centrifugation at 40,000 x g. LA contain SP-A and the surfactant lipophilic proteins SP-B and SP-C and are surface-active in vitro, whereas SA lack the surfactant proteins and have poor surface properties. ...

Adult baboons (Papio sp.; 8-12 kg) were anesthesized with sodium pentobarbital (20 mg/kg iv). The animals were instrumented for measurement of mean blood pressure (MBP), pulmonary artery pressure (PAP), ECG, arterial and mixed venous blood gases, lung volumes, lung pressures, and efferent phrenic nerve activity. Bronchoalveolar lavage (BAL) was performed. ...

To assess the short-term effects of high-frequency jet ventilation (HFJV) on the neonatal lung, 28 newborn piglets were studied. Nine piglets were unventilated except during brief pulmonary measurements, nine animals were conventionally ventilated (arterial CO2 tension 35-45 torr, arterial O2 tension 70-80 torr) for 4 h, and 10 piglets were ...

The effect of exogenous surfactant on endogenous surfactant metabolism was evaluated using a single-lobe treatment strategy to compare effects of treated with untreated lung within the same rabbit. Natural rabbit surfactant, Survanta, or 0.45% NaCl was injected into the left main stem bronchus by use of a Swan-Ganz catheter. Radio-labeled ...

Administration of bleomycin to animals results in an alteration of the pressure-volume relationship of the lungs with an increased elastic recoil at any given volume. We sought to evaluate the relative importance of surface forces to elastic recoil by comparing the differences between the air and saline pressure-volume curves. The ...

Two different formulations of phenylbutazone, one made to contain 0.5% w/v Brij 96 and the other without surfactant, were prepared by conventional crystallization and compressed to tablets by direct compression using a single punch tabletting machine fitted with 3 mm punches. The relative bioavailability of phenylbutazone was determined in Newzealand ...

We replaced the standard serial bronchoalveolar lavage technique with a new "rewash" lavage procedure to allow estimation of the volume and protein concentration of the epithelial lining fluid (ELF) in anesthetized sheep. A bronchoscope 6.0 mm in diameter wedged in an airway was used to lavage a segment of lung ...

We studied healthy and saline lavaged rabbits during high frequency oscillatory ventilation to determine what combination of frequency (f), tidal volume (Vt), and mean airway pressure (Paw) produced the lowest peak-to-peak alveolar pressure amplitude (Palv) and physiologic blood gas tensions. Sinusoidal volume changes were delivered through a tracheostomy by a ...

The acute respiratory distress syndrome (ARDS) is a common clinical catastrophe following acute lung injury. A multiplicity of clinical states can lead to ARDS. A new classification system has been proposed to deal with associated organ system failure and varying degrees of acute lung injury. ARDS is a permeability and ...

Immature newborn rabbits with a gestational age of 27 days were paralyzed and kept in body plethysmographs. They were ventilated for 10 min with a tidal volume of approximately 10 ml/kg, with or without previous surfactant treatment via the airways. Tidal volumes and flow were recorded with a pneumotachograph connected ...

We tested the cardiovascular actions of the surfactant Pluronic F68 by infusing it into anesthetized dogs, in doses approximating those which would be received when Fluosol-DA were used to resuscitate moderate or severe hemorrhage (0.66 and 1.11 g/Kg). In order to alleviate the reactions to Pluronic, the surfactant was purified ...

To determine whether atelectasis might modify lung surfactant, we injected N2 into the right pleural space of adult rabbits. Daily, under sedation, pleural gas volume and pressure were measured and adjusted to 20 ml/kg and 0 to +2 cm H2O with N2. On the sixth day, pHa, PaCO2, PaO2, and ...

To determine the efficacy of high-volume, high-pressure pulsatile lavage in the prevention of cardiopulmonary dysfunction and fat embolism during cemented arthroplasty, we studied twenty-eight mongrel dogs that had had a bilateral cemented arthroplasty. Significant increases in pulmonary-artery pressure and pulmonary vascular resistance, accompanied by decreases in arterial oxygen tension and ...

Antenatal corticosteroids reduce the incidence of the respiratory distress syndrome and improve pulmonary mechanics at least in part by mechanisms other than surfactant stimulation. We measured several aspects of pulmonary function in rabbits to better understand the mechanisms involved. Seven does were given intramuscular betamethasone and six were given vehicle ...

The purpose of this prospective and randomized study is to evaluate the safety and efficacy of prophylactic transcervical amnioinfusion in the management of labor complicated by meconium. A preexisting intrauterine pressure catheter was used for amnioinfusion. The incidence of thick meconium was significantly lower after amnioinfusion, compared with standard management ...