The response of patients with respiratory failure and cardiopulmonary disease to different levels of constant volume ventilation.

Abstract

The purpose of this study was to determine the effect of increasing the tidal volume on pulmonary ventilation-perfusion relations in patients with respiratory failure caused by cardiopulmonary disease.The frequent occurrence of an increased physiologic dead space (2, 3) and of increased physiologic shunting (3) in patients undergoing prolonged artificial ventilation has previously been described. These changes in ventilation-perfusion ratios mean that very large tidal volumes and high percentages of inspired oxygen are often required to maintain life during prolonged intermittent positive pressure ventilation. The aim of our study was to measure the consequences of changing the tidal volume, but not the respiratory frequency, of patients with respiratory failure secondary to either acute intrapulmonary infection or chronic pulmonary emphysema. MethodsSelection of patients. At the time of the study none of the twelve patients had a total vital capacity above 400 ml, and hence all were completely dependent on intermittent positive pressure ventilation. Eight of the patients studied were selected because they had been free of symptomatic pulmonary disease on admission to the hospital, but had later developed nonemphysematous cardiopulmonary disease and acute intrapulmonary infection that caused respiratory failure. Polyethylene catheters were placed percutaneously in either a radial or femoral artery and in the superior vena cava. These catheters were used for blood sampling and continuous pressure recording via a Sanborn 350 system. Continuous intratracheal pressure and the electrocardio- 1 The apparatus dead space, average volume 28 ml, extended from the tip of the tracheostomy tube lying in the trachea to the junction of the inspiratory and expiratory tubes of the ventilator, a distance of 25 cm; the internal diameter of the tubing that comprised the apparatus dead space was 1.2 cm. 1543

Effects of recruitment maneuvers in patients with acute lung injury and acute respiratory distress syndrome ventilated with high positive end-expiratory pressure*

“…Second, all patients in this study were supported with a volume and pressure-limited mechanical ventilation strategy to reduce ventilationassociated lung injury from overdistention (18). There is a greater tendency for atelectasis to occur with this approach (25)(26)(27). Effects of RMs might have lasted longer if we used higher tidal volumes with higher inspiratory pressures between RMs.…”

Ventilation with end-expiratory pressure in acute lung disease

“…A stereotyped hemodynamic response to application of PEEP cannot be expected since both the relationship between available blood volume and capacity of the intravascular bed (12) as well as the type of underlying lung disease (13) PEEP may produce regional changes in lung volume with redistribution of blood flow to ventilated-perfused and ventilated, nonperfused parts of the lung (17,18). Third, an alteration of pulmonary mechanics may lead to improved gas distribution.…”

Prevention of gram-negative bacillary pneumonia using polymyxin aerosol as prophylaxis. II. Effect on the incidence of pneumonia in seriously ill patients.

“…The criteria for the diagnosis of pneumonia were based on the presence of persistent X-ray evidence of an alveolar infiltrate on 2 or more consecutive days observed at a time when sputum cultures or tracheal aspirates were positive for potentially pathogenic organisms; an elevated alveolararterial oxygen tension difference while breathing 100% oxygen (AaDO2s1); and an evaluation of the temperature course, daily weights, central venous pressure, and SwanGanz catheter data (19).…”