The impact of closed endotracheal suctioning systems on mechanical ventilator performance

Closed endotracheal suctioning during mechanical ventilation is increasingly used, but its impact on ventilator function has not been fully studied.

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.

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.

There are large differences between the ventilators evaluated (p < 0.001). Closed suctioning does not cause mechanical ventilator malfunction. Upon removal of the suction catheter, these ventilators resumed their pre-suctioning-procedure 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.