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Start Over Author "Dinger, J." Journal european journal of pediatrics
3 results on '"Dinger, J."'

2. High frequency oscillatory ventilation near resonant frequency of the respiratory system in rabbits with normal and surfactant depleted lungs

Author

U. Winkler, Dinger J, Peter Schaller, D. Gmyrek, and Andreas Schulze

Subjects
Artificial ventilation, medicine.medical_treatment, Dead space, High-Frequency Ventilation, Mean airway pressure, Nuclear magnetic resonance, Pressure, Medicine, Animals, Normocapnia, Respiratory system, Least-Squares Analysis, Lung, Lung Compliance, Mechanical ventilation, business.industry, Pulmonary Gas Exchange, High-frequency ventilation, Pulmonary Surfactants, Oxygenation, Carbon Dioxide, Respiration, Artificial, Oxygen, Anesthesia, Pediatrics, Perinatology and Child Health, Rabbits, business
Abstract

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 adult rabbits (n = 10; 3.8-5.1 kg body weight) were ventilated by alternating periods of CMV and HFV near fr. Negative ventilator resistance was used for complete resistive unloading of the respiratory system before each HFV period. This enabled a continuous swinging at resonance thus allowing measurement of fr and selection of exactly that frequency for the HFV run. Intra-animal CMV-HFV comparisons (n = 4) were performed on each animal: with healthy lungs at a mean airway pressure (MAP) of 0.5 kPa and after saline lung lavage at MAPs of less than 1.5 kPa; 1.5-1.8 kPa; greater than 1.8 kPa. Surfactant removal caused total respiratory system compliance (Ctot) to decrease from 44 +/- 5 to 22 +/- 3 ml/kPa. Corresponding fr was 244 +/- 48 and 360 +/- 30 min-1, respectively. HFV produced effective pulmonary gas exchange but did not improve arterial oxygenation in comparison with CMV at matched MAPs both before and after surfactant depletion. Volume amplitudes of oscillation necessary to achieve normocapnia were slightly above the natural plus equipment (2 ml) dead space. Maximum intra-alveolar pressure (Pmax) was calculated for the HFV runs from MAP, Ctot, and the volume amplitude of oscillation. Pmax during CMV was nearly twice that during HFV at equivalent PaCO2 and equivalent MAPs throughout the experiments.

Published
1991

3. Functional residual capacity and compliance of the respiratory system after surfactant treatment in premature infants with severe respiratory distress syndrome.

Author

Dinger J, Töpfer A, Schaller P, and Schwarze R

Subjects
Female, Hemodynamics, Humans, Infant, Newborn, Lung physiology, Lung Compliance drug effects, Male, Pulmonary Gas Exchange drug effects, Pulmonary Surfactants administration & dosage, Respiratory Distress Syndrome, Newborn physiopathology, Time Factors, Functional Residual Capacity drug effects, Infant, Premature, Lung drug effects, Pulmonary Surfactants therapeutic use, Respiratory Distress Syndrome, Newborn drug therapy
Abstract

Unlabelled: To understand the mechanisms behind improved oxygenation after intratracheal surfactant instillation, the immediate and late effects on lung volume and compliance of the respiratory system (CRS) were analysed. Infants received modified porcine surfactant (Curosurf) or modified bovine surfactant (Alveofact). Measurements of functional residual capacity (FRC) and CRS were successfully performed in 90 ventilated preterm infants (birth weight 1264 +/- 435 g; gestational age 28.2 +/- 2.5 weeks) with severe respiratory distress syndrome. FRC and CRS were measured during mechanical ventilation prior to and 1, 3, 6, 24, 48, 72, 96, 120 and 168 h after surfactant replacement. Oxygenation rapidly improved. FRC increased significantly from 7.64 +/- 1.58 ml/kg to 15.35 +/- 3.27 ml/kg (P < 0.01) at 1 h after surfactant instillation. CRS remained virtually unchanged during the first hours after surfactant replacement and a concomitant decrease in specific compliance was seen., Conclusion: the changes in lung function following surfactant treatment can only be explained by initial stabilisation of already aerated alveoli followed by recruitment of new gas exchange units as mechanisms involved in mediating the effect of surfactant on gas exchange. However, since no significant correlation between changes in functional residual capacity and improvement in arterial-to-alveolar oxygen tension ratio was seen, other effects of surfactant must be considered. These include local and/or systemic changes in haemodynamics.

Published
2002
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