Continuous 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. The piglets were instrumented, saline-lavaged, and exposed to 15 minute periods of incremental CNEP (-3, -6, -9, -12 cmH2O) (n = 7) or PEEP (3, 6, 9, 12 cmH2O) (n = 6). We measured and/or calculated dynamic lung compliance (CLdyn), lung resistance (RL), end-expiratory lung volume (EELV), blood gases, cardiac output (CO), heart rate (HR), transmural vascular pressures, and pulmonary and systemic vascular resistance. Pulmonary function abnormalities after saline lavage included decreased PaO2, CLdyn, EELV, and increased PaCO2 and RL (P < 0.05). 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.
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Department of Pediatrics, Kapiolani Medical Center for Women and Children, John A. Burns School of Medicine, Honolulu, Hawaii 96826.
Mundie
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Finn
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Hashiro
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Balaraman
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D000403:Airway Resistance; D000818:Animals; D000831:Animals, Newborn; D002302:Cardiac Output; D006439:Hemodynamics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D008168:Lung / Q000503:physiopathology*; D008170:Lung Compliance; D008176:Lung Volume Measurements; D008954:Models, Biological; D011175:Positive-Pressure Respiration; D011659:Pulmonary Gas Exchange; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology* / Q000628:therapy*; D012129:Respiratory Function Tests; D012965:Sodium Chloride; D013552:Swine; D007507:Therapeutic Irrigation; D013997:Time Factors; D015919:Ventilators, Negative-Pressure
D012965:Sodium Chloride