Effect of Inverse I:E Ratio Ventilation on Pulmonary Gas Exchange in Acute Respiratory Distress Syndrome
| Autor: | Joan R. Masclans, Miguel Ferrer, Robert Rodriguez-Roisin, Merce Planas, A. Rossi, Guido Polese, Elizabeth Zavala, Joseph Milic-Emili, Josep Roca |
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| Rok vydání: | 1999 |
| Předmět: |
Adult
Male medicine.medical_specialty ARDS Dead space medicine.medical_treatment Hemodynamics Positive-Pressure Respiration Internal medicine medicine Humans Respiratory system Intensive care medicine Aged Aged 80 and over Mechanical ventilation Respiratory Distress Syndrome Lung Pulmonary Gas Exchange business.industry Blood flow Middle Aged medicine.disease Respiration Artificial medicine.anatomical_structure Breathing Cardiology Female business |
| Zdroj: | Survey of Anesthesiology. 43:7 |
| ISSN: | 0039-6206 |
| Popis: | Background: It is not known whether inverse I:E ratio ventilation (IRV) offers any real benefit over conventional mechanical ventilation with positive end-expiratory pressure (CMV-PEEP) at similar levels of end-expiratory pressure. Methods: The effects of volume-controlled and pressure-controlled IRV (VC-IRV and PC-IRV, respectively) on V A /Q inequality were compared with those of CMV-PEEP at a similar level of end-expiratory pressure and with CMV without PEEP (CMV) in eight patients in the early stages of acute respiratory distress syndrome (ARDS). Respiratory blood gases, inert gases, lung mechanics, and hemodynamics were measured 30 min after the onset of each ventilatory mode. Results: Recruitment of nonventilated, poorly ventilated (or both) but well-perfused alveoli increased the partial pressure of oxygen (Pa O2 ) during CMV-PEEP (+13 mmHg) and IRV-VC (+10 mmHg; P < 0.05) compared with CMV. In contrast, PC-IRV did not affect Pa O2 but caused a decrease in Pa CO2 (-7 mmHg; P < 0.05). The latter was due to a concomitant decrease in dead space (P < 0.01) and shift to the right of V A /Q distributions. During PC-IRV, the increase in the mean of blood flow distribution (mean Q; P < 0.01) without a change in the dispersion (log SD Q) did not result in an increase in Pa O2 probably because it reflected redistribution of blood flow within wellventilated areas. Conclusions: Short-term PC-IRV improved carbon dioxide clearance, but the lung became less efficient as an oxygen exchanger. Furthermore, based on mean airway and plateau pressures, the risk of barotrauma was not reduced with this type of ventilation. |
| Databáze: | OpenAIRE |
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