The Impact of Closed Endotracheal Suctioning Systems on Mechanical Ventilator Performance

BACKGROUND: Closed endotracheal suctioning during mechanical ventilation is increasingly used, but its impact on ventilator function has not been fully studied. METHODS: We evaluated the impact of closed suctioning with 11 critical-care ventilators, during assisted ventilation in pressure-support mode, pressure-assist/control mode, volume-assist/control mode, and during continuous positive airway pressure, with 2 suctioning pressures (120 mm Hg and approximately 200 mm Hg), and with 2 tidal volumes (450 mL and 900 mL). We continuously measured airway pressure, flow at the airway, and pressure distal to the catheter tip, before, during, and after a single 15-second period of continuous suctioning. RESULTS: No ventilator malfunctioned as a result of the closed suctioning. During suctioning, end-expiratory pressure markedly decreased in all modes, and peak flow increased in all modes except volume-assist/control (p < 0.001). Respiratory rate increased during suctioning in pressure- and volume-assist/control (p < 0.001) but not during pressure support or continuous positive airway pressure. Gas delivery was most altered during volume-assist/control with the smaller tidal volume (p < 0.05) and least altered during pressure-assist/control with the larger tidal volume. CONCLUSION: There are large differences between the ventilators evaluated (p < 0.001). Closed suctioning does not cause mechanical ventilator malfunc-tion. Upon removal of the suction catheter, these ventilators resumed their pre-suctioning-proce-dure gas delivery within 2 breaths, and, during all the tested modes, all the ventilators maintained gas delivery. However, closed suctioning can decrease end-expiratory pressure during suctioning. Key words: airway suctioning, closed suctioning, mechanical ventilators, lung model. [Respir Car