Articles: respiratory-distress-syndrome.
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Am. Rev. Respir. Dis. · Feb 1992
Flow and volume dependence of respiratory system flow resistance in patients with adult respiratory distress syndrome.
Using a simple and rapid technique, we studied the flow and volume dependence of the total resistance of the respiratory system (Rrs) in six patients with ARDS. At any given inflation volume, Rrs decreased progressively with increasing flow (V) according to the following hyperbolic function: Rrs = a/V + b, where a and b are constants. At any fixed inflation flow, Rrs increased progressively with increasing inflation volume. ⋯ The flow and volume dependence of Rrs found in the patients with ARDS is qualitatively similar to that previously observed in normal anesthetized paralyzed subjects. In ARDS, however, Rrs was considerably greater than in the normal subjects, indicating that besides a low respiratory compliance ARDS is characterized by a high flow resistance. This mainly reflects increased effective flow resistance of the pulmonary and chest wall tissues, although airway resistance is also higher than normal.
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Intensive care medicine · Jan 1992
Comparative StudyA comparison of continuous positive pressure ventilation, combined high frequency ventilation and airway pressure release ventilation on experimental lung injury.
In pigs with oleic induced lung injury, the effectiveness of combined high frequency ventilation (CHFV, with VDR-Phasitron) and airway pressure release ventilation (APRV) were compared to continuous positive pressure ventilation (CPPV) in a randomized study. The respiratory rate was 15/min, CPAP 8 mmHg and FiO2 0.25. PaCO2 was maintained at 5 kPa. ⋯ There was no difference in the pericardiac pressure between the 3 ventilation modes. The pressure related depressive effects on the cardiovascular function during CHFV and APRV were similar to those during CPPV. Adequate oxygenation and ventilation could be achieved with both CHFV and APRV, but these methods were not superior to CPPV.
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Clin Intensive Care · Jan 1992
ReviewLow volume ventilation with permissive hypercapnia in the Adult Respiratory Distress Syndrome.
Many animal studies have demonstrated that mechanical ventilation with high peak inspiratory pressures (PIP) can result in a form of acute lung injury closely resembling ARDS, ie characterised by hyaline membranes, granulocyte infiltration, increased pulmonary and systemic vascular permeability, and eventually proliferation of fibroblasts and type II pneumocytes. These studies have led to a concern that, in some patients, orthodox ventilatory management in severe ARDS may result in additional lung injury and, possibly, remote organ dysfunction. Mortality may be increased as a consequence. ⋯ The time scales for compensation of intracellular and extracellular acidosis are markedly different. However, even severe acute hypercapnia appears to be remarkably well tolerated. Several clinical studies suggest that the avoidance of high PIP may reduce mortality in ARDS, but a randomised trial will be required to establish whether pressure limitation and permissive hypercapnia do improve outcome.
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Extracorporeal lung assist (ELA) has been recommended for the treatment of ARDS if conventional therapy fails. However, the need for nearly complete anticoagulation is a major risk factor for hemorrhagic complications. We describe our experience with 13 ARDS patients treated with ELA using heparin-coated systems (Carmeda). ⋯ Eight of the 13 patients survived. The use of heparin-coated systems allows prolonged ELA with nearly physiological coagulation function, permitting major surgical intervention. It enhances the safety margin of extracorporeal gas exchange and may ultimately extend its indications.