Three solutions, surfactant prepared from pig lungs, a mixture of synthetic phospholipids, and saline solution, were instilled into the middle ears of rats. The middle ear pressure necessary to force the eustachian tube open was studied. Ten minutes after instillation of pulmonary surfactant there was a 0.58 +/- 0.10 kPa ...

Rabbits exposed to hyperoxia develop surfactant deficiency, abnormal lung mechanics, and increased permeability to solute. We investigated whether replenishment of depleted alveolar surfactant by the intratracheal instillation of calf lung surfactant extract (CLSE) would mitigate the increase in alveolar permeability to solute. Twenty-eight rabbits were exposed to 100% O2 for ...

Saline lavage of the lungs of eight anaesthetized New Zealand White rabbits was performed to produce a surfactant-depletion model of the neonatal respiratory distress syndrome. A characteristic change in the shape of the pressure-volume curve occurred, with the appearance of an inflection point on the inspiratory limb. The animals were ...

Bronchoalveolar lavage fluid was collected from 12 anesthetized cats by use of an endotracheal tube and syringe adapter. The safety of the technique was evaluated by monitoring mucous membrane color, capillary refill time, pulse rate, respiratory rate, ECG, and arterial blood gas tensions and by necropsy findings. Group A consisted ...

To test the hypothesis that hyaline membrane disease (HMD) has a multifactorial etiology in which barotrauma plays a major role, we compared the immediate institution of high-frequency oscillatory ventilation (HFOV; 15 Hz, n = 5) with positive-pressure ventilation with positive end-expiratory pressure (PPV; n = 7) in premature baboons (140-days ...

Immature newborn rabbits were treated at birth by tracheal instillation of porcine surfactant (100 microliters, phospholipid concentration 80 mg.ml-1), to which [14C]dipalmitoylphosphatidylcholine had been added as a marker. They were kept in a body plethysmograph/pneumotachygraph system at 37 degrees C. During a 120 min period of artificial ventilation with a ...

Bronchopulmonary dysplasia (BPD) is a distortion of postnatal lung development induced by ventilator treatment for respiratory distress syndrome or other forms of respiratory failure in the newborn. This paper reviews established and proposed mechanisms involved in the pathogenesis of BPD including severe surfactant deficiency, ventilation with high insufflation pressure and ...

Radiation pneumonitis is a life-threatening result of therapeutic thoracic irradiation, yet its mechanisms are poorly understood. We studied the effects of unilateral lung irradiation (3,000 rad) in sheep from the immediate response to the later development of radiation pneumonitis. We defined radiation pneumonitis by its diagnostic clinical feature, radiographic infiltration ...

To assess the efficacy of high frequency oscillatory ventilation (HFOV) in the management of infants with hyaline membrane disease (HMD), we compared two HFOV strategies with conventional positive pressure ventilation with positive end expiratory pressure (PPV) for 24 h in premature baboons (140 d gestation). Three out of 14 PPV, ...

Apnoeic oxygenation (AO) combined with extracorporeal CO2 removal (ECCO2R), using venovenous perfusion across a membrane area of 0.1 m2 has been shown to be feasible in six healthy anaesthetized rabbits. In a further twelve rabbits, ECCO2R has been randomly compared with conventional mechanical ventilation (CMV) following saline lavage to induce ...

In the healthy and surfactant-depleted lungs of five pigs the influence of different forms of high frequency ventilation superimposed on conventional mechanical ventilation during the expiratory phase of the ventilatory cycle (SHFVE) on gas exchange and cardiocirculatory parameters was investigated. Subsequently the effects of end-expiratory flushing (EF), i.e. cleaning the ...

The performance of a new infant ventilator system had to be evaluated. Technically it is characterized by flow (V)- and pressure (P)-transducers mounted immediately near the endotracheal tube. A microcomputer works as a function generator and governs servo-controllers for V and P thus offering a multiplicity of different modes both ...

We studied the effect on surfactant metabolism of 8 h of mechanical ventilation at tidal volumes of 13 +/- 0.3 ml/kg and very high tidal volumes of 28 +/- 1.5 ml/kg, with and without added CO2, in the presence of an atrial right to left shunt in 4- to 8-day-old ...

Hydrocarbon aspiration is responsible for substantial morbidity and mortality in both children and domestic animals. To better understand the pathogenesis of hydrocarbon poisoning, we evaluated the effects of aspiration of 0.5 ml/kg of kerosene on various pulmonary and cardiovascular variables over a 4-hr period in a canine model. Heart rate ...

Adult guinea pigs were exposed to 100% oxygen until, after 54-85 h, they developed severe respiratory insufficiency. One subgroup of animals was ventilated artificially with 100% oxygen for an additional 60-960 min. When the PaO2 was less than 15 kPa or the PaCO2 greater than 20 kPa, 1 ml of ...

In this report, an experimental approach and newly designed apparatus for liquid ventilation of preterm animals are described. Findings of age-related changes in cardiopulmonary function of this animal preparation are presented. Thirty-one lambs, 102-137 days gestation (term 147 +/- 3 days), were studied. The carotid artery, jugular vein, and trachea ...

We assessed pulmonary mechanics in 35 premature infants with respiratory distress syndrome just before and one hour after the administration of 90 mg of surfactant to each infant. Transpulmonary pressure was measured between the airway opening and an esophageal balloon with use of a differential transducer, and flow rates were ...

Effective use of high-frequency oscillatory ventilation (HFOV) may require maintenance of adequate lung volume to optimize gas exchange. To determine the impact of inflation during HFOV, sustained inflation was applied at pressures of 5, 10, and 15 cmH2O above mean airway pressure for 3, 10, and 30 s to 15 ...

The effect of profound repetitive prenatal asphyxial insults on the cardiopulmonary function of premature ventilated lambs was studied. Twenty-nine fetal lambs (approximately 138 days gestational age) were exteriorized. In 16 of these lambs, the umbilical cord was occluded for 4 min then released for 10 min. This asphyxial episode was ...

The influence of the detergent dioctyl sodium sulfosuccinate on clearance from the lungs of inhaled technetium-99m-labelled dietylenetriamine pentaacetate (99mTc-DTPA) was studied in twelve rabbits. An aerosol of dioctyl sodium sulfosuccinate or its vehicle alone was administered for 5 min prior to aerosolized 99mTc-DTPA via a bag-in-bottle system. Time-activity curves were ...

Experiments were performed to determine the effects of conventional mechanical ventilation (CMV) and high-frequency oscillation (HFO) on the clearance of technetium-99m-labeled diethylenetriamine pentaacetate (99mTc-DTPA) from lungs with altered surface tension properties. A submicronic aerosol of 99mTc-DTPA was insufflated into the lungs of anesthetized, tracheotomized rabbits before and 1 h after ...

To assess the influence of ventilatory technique on pulmonary baroinjury in experimental hyaline membrane disease, we randomized 24 premature baboons to six treatment groups according to ventilator (PPV, positive pressure ventilator; HFO, high frequency oscillator; HFI, high frequency flow interrupter) and O2 therapy FIO2 as clinically indicated, or FIO2 1.0). ...

Respiratory distress syndrome (RDS) is characterized by quantitative and qualitative disturbances of surface active substances (surfactant). Therefore, intratracheal surfactant substitution is a favored subject of clinical investigations. In our study we tried to inflate and stabilize lungs in two steps: first, lungs were rinsed with a fluorocarbon and, second, artificially ...

The site of change in pulmonary vascular resistance (PVR) after surfactant displacement with the detergent diocytl sodium sulfosuccinate (OT) was studied in the isolated canine left lower lobe preparation. Changes in PVR were assessed using the arterial and venous occlusion technique and the vascular pressure-flow relationship. Changes in alveolar surface ...

Pregnant does were treated with betamethasone, T3, the combination of beta-methasone and T3 or vehicle control on days 24 and 25 of gestation. At 26 days gestational age, pressure-volume curves and lung rupture pressures and volumes were measured in the various groups of rabbits randomized to receive saline or surfactant ...

We examined the respiratory effects of a patent ductus arteriosus in 29 premature lambs (131-135 days gestational age) after infiltrating the ductal wall with formaldehyde solution (Formalin) and placing a snare around the ductus to regulate its patency. The lambs were given sheep surfactant, paralyzed, and mechanically ventilated at birth. ...

Twenty-six premature lambs were treated by tracheal instillation of [14C]labeled natural sheep surfactant before the onset of breathing or after the establishment of respiratory distress syndrome 30 min after birth. Half of both groups were subsequently ventilated for 3 h with 100% O2 by conventional mechanical ventilation (CMV) and half ...

Pregnant does were treated with betamethasone, T3, TRH, or combinations of betamethasone plus T3 or TRH using doses of each agent known to effect lung maturation. Preterm rabbits were then delivered at 27 days gestational age, half of each group was treated with Surfactant TA, and the rabbits were ventilated ...

Plasma catecholamine levels increase dramatically at birth. To determine the contribution of adrenal catecholamine secretion to the surge in catecholamines at birth and the role in newborn adaptation, we performed surgical adrenalectomy or sham operation on near-term ovine fetuses. After recovery in utero, the animals were delivered and supported by ...

We measured the effects of corticosteroids and surfactant individually and in combination on lung pressure-volume relationships, rupture pressures, and rupture volumes. Pregnant does were injected with betamethasone (0.1 mg/kg per day im) or vehicle on days 24 and 25 of gestation, and fetal rabbits were delivered on days 26 and ...

We created a model for studying the cardiovascular and pulmonary effects of patent ductus arteriosus (PDA) in premature lambs with respiratory distress. In 47 fetal lambs at 129 to 133 days gestation (term, 145 days), we infiltrated the ductus arteriosus with formalin and placed a mechanical occluder about it so ...

By consensus, the most clinically important consequence of near drowning is hypoxemia. Whether it is due to physiologic shunting induced by diffuse alveolar flooding from saltwater aspiration or to diffuse atelectasis induced by surfactant inactivation from freshwater aspiration, both physiologic disturbances can be reversed with the institution of positive-pressure breathing ...

Healthy adult baboons exposed to 100% oxygen for 5 to 7 days maintained on continuous mechanical ventilation develop severe bilateral noncardiogenic pulmonary edema that resembles in many aspects the human adult respiratory distress syndrome (ARDS). In the present study, we evaluated the effects of hyperoxia for 5 to 6 days ...

We treated prematurely delivered rabbit pups with the synthetic surfactant that has been named Exosurf. By weight, Exosurf is 61.8% dipalmitoylphosphatidylcholine, 6.8% hexadecanol, 4.6% tyloxapol, and 26.7% NaCl. This simple mixture, suspended at 15 mg lipid X ml-1 water, has appropriate in vitro characteristics for a lung surfactant substitute. As ...

To study the effects of beta-2 agonist on tracheal fluid, surfactant and pulmonary mechanics in fetal lamb lung, ritodrine hydrochloride, a preferential beta-2 agonist, was infused i.v. at a rate of 1.3 +/- 0.4 micrograms/kg/min (mean +/- S.D.) for 24 hr into six twin chronically catheterized fetal lambs starting between ...

Increased alveolar surface tension due to surfactant deficiency is thought to result in a negative pressure surrounding pulmonary capillaries and to promote fluid filtration. To test this hypothesis, alveolar liquid pressure (Pliquid) was measured by micropuncture in isolated lungs of mature and immature fetal rabbits (with and without surfactant replacement) ...

Meconium, an ether extract of meconium, and the major free fatty acids of meconium (palmitic, stearic, and oleic acids) were all found to increase the surface tension minimum of dog lung extract in a Wilhelmy balance. Each of these fractions was instilled into the lungs of dogs (15 experimental, eight ...

The independent roles of alveolar size and surface tension in relation to lung stability were investigated in 11 different mammalian species whose body weight ranged from 0.03 to 50 kg. This range in species provided a wide variation in subgross anatomy as well as a fourfold range in alveolar diameter. ...

The influence of surfactant depletion on clearance from the lungs of inhaled technetium-99m-labeled diethylenetriamine pentaacetate (99mTc-DTPA) was studied in rabbits. Surfactant was removed by repeated lung lavage with isotone saline. To minimize structural damage to the lungs, pressure generated insufflation with short expiration was utilized. Aerosolized 99mTc-DTPA was administered via ...

We measured myocardial blood flow (QLVFW) and O2 consumption of the left ventricular free wall (VO2, LVFW) in 13 chronically instrumented, 7-wk-old lambs with an aortopulmonary left-to-right shunt (S) and in 10 control lambs without a shunt (C). The measured VO2, LVFW was compared with the calculated values obtained by ...

The aims of this study were to investigate the effects of surfactants on the beta-adrenergic responses of the arterio-arterial (lamellar) vascular pathway of isolated gills from the trout Salmo gairdneri. The resistance of the arterio-arterial vasculature was monitored by measuring the input pressure of isolated gills perfused at a constant ...

Whole cell and membrane deformability are essential for red blood cell (RBC) survival and for effective blood flow. Neonatal RBCs display several specific properties (eg, large size, high hemoglobin F) that could influence their deformation characteristics and contribute to their shortened life span. The present study was designed to compare ...

Prenatal starvation in the guinea pig causes reduced pulmonary diffusing capacity and retarded alveolarization among neonates. To study the impact of such starvation on biochemical and mechanical properties of the neonatal lung, pregnant guinea pigs were fed ad libitum throughout gestation or starved with 50% rations during their last trimester. ...

Severe respiratory insufficiency was induced in adult guinea pigs by repeated lung lavage. The animals were then ventilated for 75 min with 100% O2, insufflation pressure 28/6-8 cmH2O (2.7/0.6-0.8 kPa), frequency 30/min, and 33% inspiration time. One group of animals (I) was treated with protein-depleted porcine surfactant, prepared by a ...

The use of high oxygen concentrations and high mean airway pressures during mechanical ventilation of premature newborn infants with respiratory distress syndrome leads in 20%-30% of the survivors to chronic lung disease. This study explores if exogenous polyethylene glycol conjugated superoxide dismutase (PEG-SOD) and catalase (PEG-CAT) mitigate oxygen toxicity in ...

We compared the hemodynamic status and left ventricular (LV) performance in 7 twin pairs of preterm lambs delivered at 124 days gestational age (83% of term gestation) and ventilated by either conventional ventilation (CV) or high frequency ventilation (HFV) at 15 Hz. The lambs were treated with suspensions of natural ...

Pulmonary surfactant (PS) is capable of lowering surface tension at an air-water interface to less than 10 dynes/cm. This property of PS is believed to be important for normal lung function. We tested the detergent Tween 20, which cannot lower surface tension at an air-water interface to less than 25 ...

The time course of lung injury and recovery from a sublethal exposure to 100% O2 was investigated in adult rabbits. Animals were exposed to 100% O2 for 64 h and then returned to room air for varying periods of time up to 200 h. By the end of the exposure ...

Twelve sets of twin lambs were delivered prematurely by cesarean section at 133-136 days gestational age and ventilated for 3 h with either high-frequency oscillation (HFO) or conventional mechanical ventilation (CMV). Blood gases and pH values were monitored at 30-min intervals, and ventilator settings were adjusted to maintain CO2 partial ...

The role of prostaglandins (PG) in the pulmonary hypertension associated with high-frequency oscillatory ventilation (HFOV) was investigated in 7 pentobarbital-anesthetized dogs. The magnitude and time course of the mean pulmonary artery pressure (PAP) changes induced by HFOV (20 Hz) was quantified before and after PG-production blockade with 15 mg/kg indomethacin ...