Figure 2.

(a) Closed circuit (in‐line) suction system with heat and moisture exchanger (HME) shown as white flexitube connected to a viral/bacterial filter. (b) Servo‐Evac 180 for connection to exhalation port of ventilator. The Servo‐Evac 180 consists of a connection to the ventilator's expiratory port (curved flexitube) which empties expired air into a Evac Bag, which has a one‐way valve through which expired gas can be removed via an evacuation hose (white tube) connected to a suction source. The straight flexitube is open to the atmosphere to ensure the patient is not subjected to undue negative pressure or excessive resistance in case the suction sources is interrupted.