Pediatric pulmonology
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Pediatric pulmonology · Mar 1994
Randomized Controlled Trial Comparative Study Clinical TrialHigh frequency jet ventilation: intraoperative application in infants.
The potential advantages of the intraoperative use of high frequency jet ventilation (HFJV) when compared with conventional ventilation (CV) include the maintenance of adequate gas exchange and lung function with a relatively motionless surgical field. To determine the pulmonary response to HFJV ventilation in infants during cardiac surgery, we evaluated lung function in nine infants supported with CV and HFJV during a Blalock-Taussig shunt procedure. Infants were randomized to each mode of ventilation with inspiratory and expiratory pressures and FiO2 held constant. ⋯ Arterial PaCO2 was lower with a lower mean airway pressure on HFJV when compared with CV. The surgical team subjectively observed a diminished need for lung manipulation and improved ease of access to the surgical field with HFJV. These results indicate that the use of HFJV during closed-heart cardiac surgical procedures in infants provides similar cardiopulmonary stability and some potentially important clinical benefits when compared with CV.
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Pediatric pulmonology · Mar 1994
Comparative StudyInfrared end-tidal CO2 measurement does not accurately predict arterial CO2 values or end-tidal to arterial PCO2 gradients in rabbits with lung injury.
End-tidal PCO2 (PETCO2) measurements from two commercially available neonatal infrared capnometers with different sampling systems and a mass spectrometer were compared with arterial PCO2 (PaCO2) to determine whether the former could predict the latter in mechanically ventilated rabbits with and without lung injury. The effects of tidal volume, ventilator frequency and type of lung injury on the gradient between PETCO2 and PaCO2 (delta P(a-ET)CO2) were evaluated. Twenty rabbits were studied: 10 without lung injury, 5 with saline lavage and 5 with lung injury by meconium instillation. ⋯ The delta P(a-ET)CO2 was greater in rabbits with injured than noninjured lungs (P < 0.05). The delta P(a-ET)CO2 was similar among capnometers regardless of tidal volume, ventilator frequency, or type of lung injury. The 95% confidence interval of plots PaCO2 against PETCO2 was large for rabbits with injured and noninjured lungs.(ABSTRACT TRUNCATED AT 250 WORDS)
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Pediatric pulmonology · Mar 1994
Variations in flows and pressures during jet ventilation in the infant: a model study.
Ventilatory flow rates with either He-O2 (heliox) or N2-O2 (nitrox) mixtures during high frequency jet ventilation (HFJV) were calculated using a mathematical model, and were measured in a physical monoalveolar model of the infant lung. A constant flow was delivered to the model (Vd) drawing with it an entrained flow (Ve). When the inspiratory time (Tl) was long, a back flow (Vr) was generated that increased progressively as the alveolar pressure increased. ⋯ Tidal volume (VT) was calculated when the Tl was interrupted at Tr. The values of VT were significantly higher with helix than nitrox (P < 0.05). It is concluded that the evaluation of Tr during HFJV may provide useful information for setting the ventilator.
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Pediatric pulmonology · Mar 1994
Comparative StudyContinuous negative extrathoracic pressure versus positive end-expiratory pressure in piglets after saline lung lavage.
Recent reports have suggested that substituting continuous negative extrathoracic pressure (CNEP) for positive end-expiratory pressure (PEEP) may result in clinical benefits to infants with pulmonary disease. Other studies have suggested potential hemodynamic advantages. We compared the effects of CNEP and PEEP in 13 mechanically ventilated newborn piglets after acute lung injury induced by saline lavage. ⋯ Except for decreased CO, lung inflation with both CNEP and PEEP resulted in large increases in PaO2 without major pulmonary or hemodynamic effects. Other than differences in EELV at 3, 6, and 9 cmH2O distending pressure, there were no differences in pulmonary function or hemodynamics between sequences of incremental CNEP and PEEP. We conclude that CNEP and PEEP are physiologically equivalent in this model of acute lung injury.