Endotracheal suctioning is a procedure that removes mucus and other secretions from the airway of someone who has a breathing tube. When a patient is intubated or on a ventilator, the tube bypasses the body’s normal ability to cough and clear the throat, so secretions build up and can block airflow. A thin, flexible catheter connected to a vacuum source is inserted through the breathing tube to suction out that buildup, keeping the airway open and the lungs functioning.
Why Suctioning Is Needed
Under normal circumstances, tiny hair-like structures lining your airways sweep mucus upward, and coughing handles the rest. A breathing tube disrupts both of those mechanisms. Mucus accumulates, and without intervention it can partially or fully obstruct the tube, making ventilation harder and raising the risk of infection.
Suctioning is typically triggered by specific signs rather than performed on a fixed schedule. Visible secretions in the tube, coarse crackling sounds heard through a stethoscope, a drop in oxygen levels, and increased resistance on the ventilator all signal that it’s time. On the ventilator display, a jagged “sawtooth” pattern on the airflow waveform or a spike in the pressure needed to deliver each breath are reliable indicators. The goal is to suction only when clinically needed, not routinely, because each pass carries some risk.
Patients who commonly require suctioning include those under sedation (where the cough reflex is suppressed), people with neuromuscular conditions that weaken the muscles used to cough, anyone producing excessive mucus due to infection or inflammation, and patients who have aspirated food or liquid into the airway.
Open vs. Closed Suctioning
There are two main approaches. In open suctioning, the patient is briefly disconnected from the ventilator, and a single-use catheter is inserted into the breathing tube. In closed suctioning, a reusable catheter is built into the ventilator circuit so the patient stays connected throughout the procedure. The closed system was introduced in the late 1980s and can remain in place for 24 hours or longer before being replaced.
Closed suctioning has several practical advantages: it maintains the positive pressure the ventilator delivers to keep the lungs inflated, it reduces exposure to airborne secretions for healthcare workers, and it tends to cause less of a drop in oxygen levels during the procedure. However, a Cochrane review of multiple trials found that closed systems were associated with higher rates of bacterial colonization in the catheter, roughly 1.5 times the rate seen with open suctioning. Neither system has shown a clear advantage in preventing pneumonia or reducing mortality overall, so hospitals choose based on the patient’s condition and their own protocols.
How the Procedure Works
Before suctioning, the care team increases the patient’s oxygen concentration, typically to 100%, for about one minute. This “pre-oxygenation” step builds a buffer so the brief interruption in normal airflow doesn’t cause a dangerous drop in blood oxygen. Research confirms that skipping this step leads to significant decreases in oxygen saturation, while pre-oxygenation at 100% largely prevents that. Some evidence suggests that raising oxygen by just 20% above the patient’s baseline may also be sufficient in many adults and children.
The catheter itself is sized to be no larger than half the inner diameter of the breathing tube. A common formula used by respiratory therapists is to subtract 2 from the tube size in millimeters, then multiply by 2, giving the catheter size in French units. Using a catheter that’s too large can block airflow almost entirely, create excessive negative pressure inside the lungs, and increase the risk of tissue damage.
Once inserted, the catheter is advanced to just beyond the tip of the breathing tube (a technique called shallow suctioning) rather than deep into the lower airways, which reduces trauma to the airway lining. Suction is applied as the catheter is slowly withdrawn, and the entire pass should last no more than 10 to 15 seconds. Some clinicians gently rotate the catheter during withdrawal to collect secretions from the tube walls.
The vacuum pressure is adjusted based on how thick the secretions are. For thin, watery mucus, pressures in the range of 80 to 120 mmHg are effective and safe. Moderately thick secretions call for around 150 mmHg, while very thick, sticky mucus may require up to 200 mmHg. A 2024 randomized trial of 438 ICU patients found that matching suction pressure to mucus thickness minimized changes in heart rate and blood pressure while also reducing bleeding from the airway lining.
Risks and Complications
The most common complication is a temporary drop in blood oxygen, which can trigger changes in heart rate, irregular heart rhythms, and shifts in blood pressure. In rare cases, severe or prolonged oxygen deprivation during suctioning can lead to cardiac arrest. Pre-oxygenation and keeping each suction pass under 15 seconds are the primary safeguards. Studies show that oxygen levels typically return to baseline within about three minutes after the procedure, and lung volume recovers within roughly 60 seconds in most patients.
Excessive suction pressure or repeated passes can injure the delicate tissue lining the airway, causing bleeding. There is also a small risk of collapsing portions of the lung (atelectasis) if too much air is pulled out. Suctioning can temporarily raise pressure inside the skull, which is a particular concern for patients with brain injuries or elevated intracranial pressure. In those cases, extra precautions are taken to manage head pressure before and during the procedure.
What Patients and Families Can Expect
If you or a loved one is on a ventilator, suctioning will happen as often as secretions require it, sometimes several times a day. For the patient, it can cause brief coughing, a sensation of breathlessness, and mild discomfort. Sedated patients may not be aware of the procedure at all. The care team monitors heart rate and oxygen levels continuously during and after each pass, watching for any signs of distress.
There are no absolute reasons suctioning can never be performed, because leaving a blocked airway untreated is more dangerous than the procedure itself. However, timing matters. In newborns who have received surfactant (a medication that helps keep the lungs open), suctioning is typically delayed for 15 to 30 minutes to allow the medication to take effect. Nurses and respiratory therapists assess the patient before each session, checking breath sounds, ventilator readings, and visible secretions to confirm the procedure is actually needed rather than performing it by the clock.
After suctioning, the team listens to the lungs again and checks ventilator waveforms to confirm the airway is clearer. Improved breath sounds, lower peak airway pressures, and a return to normal oxygen levels all indicate the procedure was effective.