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Previously the acute pulmonary responses to Survanta were studied by monitoring intermittent changes in ventilatory and blood gas measurements. This study is designed to continuously characterize the acute response to Survanta during the 60 minutes following the initial dose administered to premature infants weighing 650-1500g diagnosed with significant RDS (a/A PO2≤ 0.3) prior to 2 hours of life. For the study duration (10 min prior to and 60 min following treatment) oxygen saturation, ventilator rate, and tidal volume are maintained within target ranges 93-98%, 45-60/min, and 5-7mL/kg, respectively. Survanta 4 mL/kg is administered intratracheally using a 5 Fr TrachCare MAC™ without interrupting ventilation. Software for the Drager Babylog 8000 ventilator allows continuous monitoring and recording of ventilator parameters, including FiO2, minute ventilation, MAP, and others. SaO2 is continuously monitored and recorded at 5 min intervals. Acute effects on FiO2 for the initial 9 patients indicate a marked linear decrease in FiO2(± SEM) during the 30 minutes following dosing, with a continued decline thereafter. The a/A PO2 ratio increased by two fold, and SaO2 was kept stable throughout. Other parameters are being evaluated. No administration side effects were observed. Enrollment is expected to total 40 infants.

Universal calcium (Ca) therapy in the first days of life for VLBW infants with a total serum Ca < 7.0 mg/dl may pose unnecessary risks. Total serum Ca may not adequately reflect Ca status. We evaluated the use of ionized Ca obtained with blood gas measurements in a clinical setting to determine if we could decrease the number of infants treated for hypocalcemia. Forty infants< 1500 grams birthweight requiring mechanical ventilation were enrolled in the study. Both ionized Ca and total serum Ca were simultaneously measured at 12, 24, 36, and 48 hours of age. A Smooth E syringe from Radiometer was used to collect 0.3 ml of blood for an ABG and ionized Ca and values measured on a Radiometer ABL 505 Analyzer. The total serum Ca was measured on a Kodax EKTACHEM 700 Chemistry Analyzer. An EKG was obtained at 24 hours of life to evaluate changes associated with hypocalcemia. Infants were also assessed for any clinical symptoms of hypocalcemia. If the ionized Ca was < 0.80 mmol/l, therapy for hypocalcemia was instituted.

Summary: Premature lambs at 118 to 122 days of gestation were delivered by caesarean section and received before the first breath 0, 19, 53 or 64 mg natural surfactant total lipid (TL) per kg body weight (BW). The seven lambs receiving no surfactant died within 40.1 ± 7.5 min, whereas the lambs treated with surfactant survived the 2-hr experimental period. Nineteen mg surfactant TL per kg BW preserved lung function; the pH and blood gas measurements were similar to those measured in lambs receiving 53 mg TL per kg BW or more surfactant. Pressure volume and surface tension characteristics were significantly improved after the administration of 19 mg of surfactant, but surface activity was still poor when compared to lambs receiving 53 mg TL per kg BW or more surfactant. The dose of surfactant (53 mg TL per kg BW) that resulted in good surface activity measurements in vitro was similar to other estimates of the amount of surfactant necessary to cover the alveolar space. Speculation: Differences were observed in the quantities of surfactant needed to normalize the clinical status and the pressure-volume and surface balance characteristics of the excised lungs and lung extracts. This may indicate that clinical status is the better way to evaluate the surfactant replacement therapy.