Closed suctioning protected lung volume briefly in ARDS, without changing outcomes

Design

Single-centre, prospective, randomised controlled trial with electrical impedance tomography

Population

60 patients with ARDS on PEEP of 5 to 10 cmH2O

Primary outcome

Change in end-expiratory lung impedance and oxygenation after suctioning

Effect

Global change at 1 minute -0.54 (closed) vs -2.32 (open), P < 0.001; PaO2/FiO2 at 30 minutes no difference

A single-centre trial randomised 60 patients with ARDS on lung-protective ventilation and PEEP of 5 to 10 cmH2O to open or closed endotracheal suctioning. Lung volume change was tracked with electrical impedance tomography, and oxygenation with pulse oximetry and arterial blood gases.

Immediately after suctioning, loss of end-expiratory lung volume was smaller with closed suctioning (global change -0.54 against -2.32 at 1 minute, P < 0.001). Lung volume recovered faster with open suctioning, to baseline by 20 minutes against 30 minutes with closed. Oxygen saturation at 1 minute was higher with closed suctioning (99.03% vs 98.07%), but the oxygenation index at 30 minutes, extubation and survival did not differ. No adverse events were recorded.

The differences were physiological and brief. The trial was too small to show an effect on patient outcomes, and the units of impedance change are arbitrary.

• Closed suction systems remain a reasonable choice in patients with ARDS who have high PEEP requirements
• Expect a transient dip in lung volume with any suctioning and monitor saturation
• Allow time for recovery before further interventions after suctioning
• Do not expect a difference in survival from the choice of method

Why it matters

Routine bedside procedures cause measurable physiological change, and this quantifies it.

Don't overread it

Sixty patients and short-lived physiological differences cannot show that one method improves outcomes.

The statistics, in plain English

The trial measured changes in lung impedance, a physiological marker, over 30 minutes, and found real but short-lived differences. Larger trials with clinical endpoints such as ventilator days or mortality would be needed to show that the method matters for patients.

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