1. Introduction
Endotracheal suction is a common method to
clean airway from discharge in patients
undergoing mechanical ventilation [1]. Suction
is done to extract discharge, improve oxygen
supply and also to prevent tracheal obstruction.
However, this procedure would bring about
atelectasis, increase breathing as well as lung
infections. In addition to extracting discharge
and keeping the airway open, endotracheal
suction can cause some side effects [2].
Respiratory infections are among the most
common complications caused by suction [3].
Severe side effects such as hypoxia, decreased
heart rate and its disorder, increased intracranial
pressure, atelectasis, mild and severe
hemorrhage, tracheobronchial rupture,
emphysema, pneumothorax, infection [in both
patients and their care givers), cardiac arrest
and even death can occur due to suction [4,5].
The numbers of suctions vary in each patient
but the average is eight to seventeen times per
day [2]. There are two techniques for suction:
the open suction system (OSS) and the closed
suction system (CSS). In OSS, the patient is
removed from the ventilator during the suction
[6]. In this method, since oxygen, humidity and
peep are not delivered to the patient during
suction, small airways and alveoli would
collapse [7]. In CSS, there is no need to
disconnect the patient from the device. In
contrast with OSS, in this method suction
catheter is placed between trachea pipe and
mechanical ventilation machine and according
to the organization’s regulations it would
remain there for 24 hours. It can be used for
suction for many times [6]. OSS is the most
usual method for trachea suction. It requires
removal of the patient from ventilation machine
during the procedure, which results in decrease
of pressure in airways and also reduction of
lungs volume. Therefore, OSS may lead in
decrease of air alveoli, reduction of lung
volume and hypoxia [8]. CSS has been the
center of attention in recent decades in a way
that in the U.S. intensive care units about 58%
of suctions are carried out through CSS and 4%