How to Suction a Patient: Step-by-Step Procedure

Suctioning a patient’s airway involves inserting a sterile catheter into an endotracheal tube, tracheostomy, or the oropharynx and applying negative pressure to remove accumulated secretions that the patient cannot clear independently. The procedure sounds straightforward, but the details matter: catheter size, suction pressure, insertion depth, duration of each pass, and pre-oxygenation all affect whether the patient comes through the procedure safely or develops complications ranging from oxygen desaturation to dangerous heart-rate drops. What follows is a practical walkthrough of each step, grounded in current clinical evidence and guideline recommendations.

When Suctioning Is Actually Needed

Suctioning is not done on a fixed schedule. Clinical guidelines have moved away from routine timed suctioning toward an “as-needed” approach based on patient assessment. The signs that a patient needs suctioning include visible or audible secretions in the airway, a sawtooth pattern on the ventilator’s flow waveform, rising peak inspiratory pressures, audible gurgling or coarse breath sounds on auscultation, coughing, and declining oxygen saturation without another obvious cause. A validated assessment framework, the Endotracheal Suction Assessment Tool, evaluates eight respiratory and ventilation parameters alongside seven clinical considerations to help clinicians decide whether suctioning is warranted.¹

The key principle is that suctioning itself carries risks, so it should only be performed when the clinical picture justifies it. Suctioning a patient “just in case” or at arbitrary intervals exposes them to unnecessary drops in oxygen levels, airway trauma, and hemodynamic instability without a clear benefit.

Gathering Equipment and Choosing the Right Catheter

Before touching the patient, you need everything within arm’s reach: a suction catheter of the appropriate size, a functioning suction source with a collection canister, connecting tubing, sterile gloves, eye protection, sterile saline or water for rinsing the catheter, a manual resuscitation bag or ventilator capable of delivering increased oxygen, and a pulse oximeter. Having to step away mid-procedure to grab a forgotten item means leaving an unstable airway unattended.

Catheter sizing follows a simple rule: the outer diameter of the suction catheter should not exceed half the inner diameter of the endotracheal tube in adults and pediatric patients. A bench-top study simulating acute respiratory distress syndrome conditions confirmed that exceeding that 50% threshold destabilizes positive end-expiratory pressure, the lung-protective pressure that keeps the small airways from collapsing during mechanical ventilation.² For neonates, guidelines allow up to 70% occlusion of the tube lumen because their tubes are already so small that a strict 50% limit would leave an impractically tiny catheter.³ In practical terms, a common adult endotracheal tube with a 7.5 or 8.0 mm inner diameter pairs with a 12 or 14 French catheter.

Pre-Oxygenation Before You Begin

Every pass of the suction catheter removes air along with secretions, temporarily dropping the patient’s oxygen levels. Pre-oxygenation, giving the patient a higher concentration of oxygen before the procedure, builds a buffer against that drop. A trial in ICU patients found that pre-oxygenating for at least one minute caused significantly less disruption to arterial oxygen saturation than a 30-second pre-oxygenation period.⁴ In preterm neonates, the evidence is even more striking: a Cochrane review found that pre-oxygenation before suctioning dramatically reduced the number of infants who became hypoxemic, and babies who received pre-oxygenation returned to their baseline oxygen levels about two minutes faster than those who did not.⁵

That said, the appropriate level of oxygen during pre-oxygenation is not “as high as possible.” A cluster-controlled trial found that a strategy using lower inspired oxygen concentrations without suctioning during extubation actually reduced respiratory complications by about 23% compared to a high-oxygen-plus-suctioning strategy.⁶ The takeaway: pre-oxygenate, but match the oxygen level to the patient’s actual needs rather than reflexively cranking it to 100%.

The Suctioning Procedure Step by Step

Once equipment is ready, the patient is pre-oxygenated, and your hands are gloved, the sequence is as follows:

Connect and test: Attach the suction catheter to the suction tubing, turn the wall suction to continuous, and confirm you feel negative pressure at the catheter tip by briefly occluding the suction-control vent with your thumb.
Insert without suction: With the suction-control vent open (so no vacuum is being applied), advance the catheter gently through the endotracheal tube or tracheostomy tube. For shallow suctioning, insert to just beyond the tip of the artificial airway. For deeper suctioning, advance until you meet slight resistance, then pull back slightly.
Apply suction on withdrawal only: Place your thumb over the suction-control vent to activate negative pressure, and slowly withdraw the catheter with a gentle rotating motion. Never apply suction while pushing the catheter deeper.
Limit each pass: The entire suction event from insertion to withdrawal should take no longer than 10 to 15 seconds.⁷ Prolonging the pass beyond that window significantly increases the risk of oxygen desaturation and mucosal damage.
Re-oxygenate between passes: Reconnect the patient to the ventilator or bag and allow several breaths before considering a second pass. Monitor pulse oximetry throughout.
Rinse the catheter: Flush the catheter with sterile water or saline between passes to keep the lumen clear.
Repeat only if necessary: Additional passes should be driven by ongoing clinical signs that secretions remain. Two or three passes is typical; each additional pass raises the cumulative risk of complications.

For tracheostomy suctioning specifically, the same principles apply. Advance the catheter through the stoma until resistance is met, slightly retract, then apply suction while withdrawing with a twisting motion, keeping each pass under ten seconds.⁸

How Much Suction Pressure to Use

Too little pressure and you accomplish nothing; too much and you damage the airway lining. The American Association for Respiratory Care recommends keeping suction pressure below 200 mmHg (about 27 kPa) for adults and below 120 mmHg for neonates and pediatric patients.³ Some neonatal guidelines are even more conservative, suggesting pressures below 100 mmHg for intubated newborns.⁷ The guiding principle is to use the lowest effective pressure: start low, and increase only if secretions are too thick to clear.

Shallow Versus Deep Suctioning

This is one of the more actively debated areas in airway management. In shallow suctioning, you insert the catheter only to the tip of the endotracheal or tracheostomy tube. In deep suctioning, you advance the catheter until you feel resistance at the carina, the point where the trachea splits into the two main bronchi, and then pull back before applying suction.

A study comparing the two approaches in mechanically ventilated patients found that deep suctioning caused significantly greater increases in heart rate and blood pressure, and led to far more complications. Tracheal tissue injury occurred in every patient in the deep suctioning group, compared to less than half of those in the shallow suctioning group. Hypoxemia and cardiac rhythm disturbances were also significantly more common with deep suctioning.⁹

The picture is not entirely one-sided, though. A separate randomized trial found that shallow and deep suctioning produced similar effects on respiratory rate and oxygen saturation, but shallow suctioning required more catheter passes to clear secretions, meaning more repeated manipulation of the trachea overall.¹⁰ The current weight of evidence favors shallow suctioning as the default approach for most patients, with deep suctioning reserved for situations where secretions cannot be cleared any other way.

Open Versus Closed Suction Systems

An open suction system requires disconnecting the patient from the ventilator, inserting a single-use catheter, suctioning, withdrawing the catheter, and then reconnecting the ventilator circuit. A closed system keeps the catheter enclosed in a sterile sheath within the ventilator circuit, so the patient is never disconnected. The closed system is faster, avoids the loss of lung volume that comes with disconnection, and seems like it should be cleaner.

The infection question has produced mixed results. A Cochrane review of 16 trials found no significant difference between the two systems in ventilator-associated pneumonia rates, mortality, or ICU length of stay. Surprisingly, the closed system was actually associated with higher bacterial colonization of the catheter.¹¹ However, a more recent meta-analysis found the opposite result for pneumonia: open suctioning increased the risk of ventilator-associated pneumonia by about 57% compared to closed suctioning.¹² A single-center comparative study found pneumonia and mortality rates were similar between the two systems.¹³

Where closed systems clearly win is in maintaining lung recruitment. Patients on high levels of positive end-expiratory pressure, such as those with acute respiratory distress syndrome, lose that protective pressure every time the circuit is broken. For these patients, closed suctioning is strongly preferred. For patients on lower ventilator settings, the choice is less clear-cut, and institutional protocols vary.

Why Squirting Saline Down the Tube Is Falling Out of Favor

For decades, many nurses instilled a small bolus of normal saline into the endotracheal tube before suctioning, believing it would loosen thick secretions and make them easier to remove. This practice persists in some units, but the evidence has turned against it. A systematic review and meta-analysis found that instilling saline before suctioning was associated with drops in oxygen saturation, prolonged recovery time to baseline oxygenation, decreased arterial pH, and increases in heart rate and blood pressure. The only apparent benefit was a reduction in ventilator-associated pneumonia, but this was outweighed by the cumulative harmful effects. The review’s conclusion was blunt: routine saline instillation before suctioning should be avoided.¹⁴

A separate multimethod study confirmed that saline instillation decreased oxygenation in most studies, while its effects on hemodynamics and pneumonia risk were unclear.¹⁵ Despite this, some clinicians still use it when secretions are exceptionally thick and repeated suctioning has failed. The evidence suggests that if saline instillation is used at all, it should be a last resort, not a default step.

Complications and How to Spot Them

Suctioning is an invasive procedure that triggers predictable physiologic responses. The most common complication is transient oxygen desaturation, which is why pre-oxygenation and short pass durations matter. But the more dangerous complications involve the heart.

Suctioning stimulates the vagus nerve, which runs along the trachea. In susceptible patients, this can provoke a sudden and severe drop in heart rate. A classic study of tetraplegic patients documented that tracheal suctioning induced bradycardia in all four subjects, with two experiencing outright cardiac arrest. The bradycardia occurred when patients were already hypoxic and was prevented by supplemental oxygen or, when oxygen alone was insufficient, by administering atropine.¹⁶ Another study confirmed that endotracheal suctioning can drop heart rate from above 110 beats per minute to around 45 beats per minute, and that nebulized atropine given beforehand prevented this response.¹⁷

In practice, this means cardiac monitoring is essential during suctioning. If a patient has a history of vagal sensitivity, spinal cord injury, or has shown heart-rate drops during previous suctioning events, the clinician should be prepared with atropine and ensure thorough pre-oxygenation before each attempt.

The Patient’s Experience of Being Suctioned

It is easy to focus on the technical steps and forget that suctioning is deeply unpleasant for a conscious patient. A descriptive study of awake, acutely and critically ill adults found that while the average pain score during suctioning was mild, more than half of the patients who reported pain described it as moderate to severe. Surgical patients, younger patients, and non-white patients tended to report higher pain intensities. Few patients had received any analgesics in the hour before the procedure.¹⁸

Beyond pain, suctioning triggers a significant and immediate spike in the sensation of breathlessness. A prospective study of mechanically ventilated patients found that self-reported dyspnea scores more than doubled during suctioning and, in about 15% of cases, had not returned to baseline five minutes after the procedure ended.¹⁹ For conscious patients, explaining what is about to happen, working quickly, and considering pre-procedural analgesia can make a meaningful difference. Communication strategies for tracheostomized patients, who cannot speak and may feel especially anxious, are considered a key element of quality nursing care during these procedures.²⁰

Infection Control Gaps in Practice

The sterile or clean technique used during suctioning is one of the most important safeguards against introducing bacteria into the lower airway. Guidelines call for hand hygiene before and after the procedure, sterile or clean gloves depending on the system used, and personal protective equipment including face protection. In reality, adherence is often poor. A cross-sectional study of critical care nurses found that roughly two-thirds did not perform hand washing before suctioning, most did not wear aprons or face masks, and none wore goggles.²¹

These lapses are not harmless. Every suctioning event creates an opportunity for contamination, and the catheter is being threaded directly into the lower respiratory tract. Whether you are using open or closed suctioning, maintaining a clean or sterile field, wearing gloves, and performing hand hygiene before and after remain non-negotiable steps. The procedure can be done well in under a minute; the infection control steps that bookend it should not be the parts that get skipped.

Differences in Neonatal and Pediatric Patients

Suctioning a newborn is not simply a scaled-down version of suctioning an adult. Neonatal airways are smaller, more fragile, and more reactive. The AARC guidelines specify that suction catheters should occlude less than 70% of the endotracheal tube lumen in neonates (versus less than 50% in adults), and that suction pressure should stay below 120 mmHg for neonatal and pediatric patients, compared to 200 mmHg for adults.³

The evidence also suggests that routine hyperoxygenation (giving much higher oxygen concentrations before suctioning) should not be used reflexively in newborns, as premature infants are vulnerable to oxygen toxicity.⁷ Pre-oxygenation is still recommended, but the oxygen level should be only modestly above the baby’s baseline rather than pushed to 100%. Additionally, the recommendation that suctioning be performed by at least two people is particularly emphasized in neonatal care, where one person manages the catheter while the other monitors the infant and provides support.

Subglottic Secretion Drainage as a Complementary Strategy

Standard suctioning removes secretions that have already reached the lower airway through the endotracheal tube. But a significant volume of contaminated secretions pools above the cuff of the tube, in the subglottic space, and can leak past the cuff into the lungs. Specialized endotracheal tubes with a separate suction port above the cuff allow this reservoir to be drained independently, a technique called subglottic secretion drainage.

A meta-analysis of randomized controlled trials found that subglottic secretion drainage was associated with a significantly lower risk of ventilator-associated pneumonia and shorter ICU stays, though it did not reduce mortality. Both intermittent and continuous drainage methods were effective, with no significant difference between them.²² In cardiac surgery patients specifically, a before-and-after study found that routine perioperative subglottic drainage was associated with substantially lower pneumonia rates compared to a period when the practice was not in use.²³

Subglottic drainage does not replace standard endotracheal suctioning; the two target different anatomic locations and different types of secretions. But for patients expected to remain intubated for more than a day or two, using an endotracheal tube equipped with a subglottic drainage port is one of the more solidly supported preventive measures against ventilator-associated pneumonia. The tubes cost more and the drainage port can become blocked, but the infection-prevention benefit has held up across multiple trials and patient populations.