Each suction pass should last no more than 15 seconds. This is the standard across adults, children, and neonates, as recommended by the American Association for Respiratory Care (AARC) in both their 2010 and most recent clinical practice guidelines. Going beyond 15 seconds increases the risk of pulling too much oxygen out of the airway, which can cause a dangerous drop in blood oxygen levels and, in some cases, a slowed heart rate.
The 15-Second Rule
The 15-second limit refers to the time suction is actively applied, from the moment you begin withdrawing the catheter to the moment it’s out. It does not include the time spent inserting the catheter (suction should not be applied during insertion). This window applies regardless of whether you’re suctioning through an endotracheal tube, a tracheostomy, or the nasopharynx.
Timing yourself matters more than you might expect. In a high-pressure clinical moment, 15 seconds can feel very short, and it’s easy to overshoot. Some practitioners count to themselves or watch a clock to stay within the limit. If you haven’t cleared all the secretions in one pass, the correct response is to stop, let the patient recover, and try again rather than extending the suction time.
How Many Passes Are Safe
Guidelines vary slightly depending on the source and the type of suctioning. For tracheostomy suctioning, you can repeat the procedure up to three times per session, as long as gurgling or bubbling sounds are still present and the patient tolerates it. For endotracheal suctioning through an artificial airway, some protocols limit you to two catheter insertions per session. If the patient’s breathing doesn’t improve or worsens after that, it’s time to escalate care rather than keep suctioning.
Between each pass, allow the patient 30 to 60 seconds to recover. Ideally, you want their oxygen saturation to return to baseline before you go in again. This recovery window is just as important as the 15-second suction limit itself, because it gives the lungs time to re-expand and reoxygenate.
Pre-oxygenation Before Suctioning
Before you begin suctioning, the patient should receive 100% oxygen. The AARC recommends preoxygenation for both pediatric and adult patients. Research comparing suctioning techniques found that three minutes of 100% oxygen before the procedure prevented dangerous drops in blood oxygen and provided a protective buffer for up to three minutes afterward. While three minutes is longer than some protocols require, the principle is consistent: build up the patient’s oxygen reserves before you temporarily interrupt their air supply.
This step is especially critical for patients who are already on a ventilator or who have compromised lung function. Skipping preoxygenation or cutting it short is one of the most common reasons patients desaturate during suctioning.
Shallow vs. Deep Suctioning
How far you insert the catheter also affects patient safety. Shallow suctioning means advancing the catheter only to the tip of the artificial airway (endotracheal tube or tracheostomy tube) without going beyond it. Deep suctioning means pushing past the tube tip until you meet resistance or trigger a cough or gag reflex.
Current AARC guidelines recommend using shallow suctioning as the default approach. Deep suctioning should only be used when shallow suctioning fails to clear the secretions. Deep insertion is more likely to irritate or damage the airway lining and can provoke stronger vagal responses, including drops in heart rate. The 15-second time limit applies equally to both depths, but deep suctioning carries more risk within that same window.
Suction Pressure Settings
Using too much suction pressure can damage delicate airway tissue, while too little won’t clear secretions effectively. The recommended ranges are:
- Adults: Keep negative pressure below 200 mmHg (often set between 100 and 150 mmHg in practice).
- Children and neonates: Keep negative pressure below 120 mmHg. For neonatal resuscitation specifically, the American Heart Association recommends not exceeding 100 mmHg.
Catheter Size and Airway Occlusion
The suction catheter needs to be small enough relative to the airway tube that air can still flow around it. If the catheter blocks too much of the tube, you’re essentially sealing off the patient’s air supply for the entire pass, which makes even a brief suction event more dangerous.
For pediatric and adult patients, the catheter’s outer diameter should occlude less than 50% of the endotracheal tube’s inner diameter. For neonates, this threshold is slightly more generous at less than 70% of the tube diameter, reflecting the smaller tube sizes used. These ratios ensure enough space remains for air to pass around the catheter during the procedure.
When to Suction
Suctioning should be done on an as-needed basis, not on a fixed schedule. The AARC recommends against routine timed suctioning for neonatal and pediatric patients, and the same principle applies broadly. Signs that a patient needs suctioning include audible gurgling or bubbling breath sounds, visible secretions in the airway tube, and a sawtooth pattern on the ventilator waveform (a jagged, irregular tracing that suggests secretions are partially obstructing airflow). In neonates, a sudden increase in airway resistance may be the key indicator.
Unnecessary suctioning carries real risks. Each pass can irritate the airway lining, trigger coughing or bronchospasm, and temporarily reduce oxygen levels. Suctioning only when clinical signs are present keeps the benefit-to-risk ratio in the patient’s favor.
Complications of Prolonged Suctioning
The two most common complications are hypoxemia (a drop in blood oxygen) and bradycardia (a slowed heart rate). Hypoxemia happens because the suction catheter pulls air out of the lungs along with secretions, and it worsens the longer suction is applied. Preoxygenation largely prevents this when done properly. Bradycardia is triggered by stimulation of the vagus nerve in the airway, and it has become less common as guidelines have moved away from deep and prolonged suctioning. Both complications are more likely when suction events exceed 15 seconds, when too many passes are performed without adequate recovery time, or when preoxygenation is skipped.