Incentive spirometry is not formally contraindicated in pulmonary embolism by any major respiratory or cardiology guideline, but the question sits in a gray zone where outdated expert opinion, theoretical risk, and a near-total lack of direct evidence converge. The concern traces back to decades-old recommendations about lung function testing after cardiovascular events, and those recommendations have themselves been flagged as needing revision. In practice, clinicians sometimes withhold the device out of caution, but the reasoning behind that caution is thinner than most people assume.
Where the Worry Comes From
The idea that incentive spirometry might be dangerous in pulmonary embolism did not originate from a study showing harm. It grew out of older guidelines on pulmonary function testing, which list recent PE as a “high-risk contraindication” alongside conditions like recent heart attack and ascending aortic aneurysm. A review published in the Postgraduate Medical Journal pointed out that these contraindication lists were based on expert opinion from more than 30 years ago and have seen little scientific scrutiny since. The authors called for the principle absolute and relative contraindications to be revised and for the recommended abstention periods to be reexamined.1Oxford Academic (Postgraduate Medical Journal). Republished review: An update on contraindications for lung function testing
Full pulmonary function testing and incentive spirometry are not the same thing. Formal lung function tests often involve forceful maximal exhalation (spirometry with forced vital capacity maneuvers), which generates significant intrathoracic pressure changes. Incentive spirometry, by contrast, involves slow, sustained inhalation against a visual target. The effort is gentler, the pressure swings are smaller, and the patient controls the pace. Yet because both fall under the broad umbrella of “breathing maneuvers,” restrictions on one tend to get applied to the other in hospital practice, often without distinguishing between the two.
What the Device Actually Does to Your Chest and Circulation
When you take a slow, deep breath using an incentive spirometer, you create a negative pressure inside your chest. This draws air into collapsed or underventilated areas of the lung, which is the whole therapeutic point: preventing or reversing atelectasis (the partial collapse of lung tissue that commonly follows surgery or prolonged immobility). That same negative intrathoracic pressure also pulls more blood into the right side of the heart from the large veins, temporarily increasing venous return.
In a healthy person, this is a trivial hemodynamic fluctuation. In someone with a pulmonary embolism, the right ventricle is already working against a partially blocked pulmonary vascular bed. The theoretical worry is that a sudden increase in venous return could further stress an already strained right ventricle, or that the pressure changes might somehow dislodge a clot. Research on deep inspiration maneuvers in spontaneously breathing patients has confirmed that these breaths do produce measurable hemodynamic shifts, including changes in pulse pressure and venous flow.2Hindawi. Hemodynamic Changes during a Deep Inspiration Maneuver Predict Fluid Responsiveness in Spontaneously Breathing Patients However, these studies were conducted in patients with sepsis and acute pancreatitis, not PE, and the maneuvers were used diagnostically, not therapeutically. Extrapolating from that population to PE patients requires a leap the data does not support on its own.
The concern about clot dislodgement is even more speculative. No published case series or controlled study has demonstrated that the gentle negative pressure generated during incentive spirometry can mobilize a thrombus lodged in the pulmonary vasculature. The clot is embedded in an arterial bed under systemic arterial pressure conditions; the intrathoracic pressure changes from a slow deep breath are orders of magnitude smaller than what it would take to physically move such a clot.
The Actual Safety Record of Incentive Spirometry
One of the more striking facts in this area is how clean the safety profile of incentive spirometry actually is. A review of complications associated with mechanical aids to lung inflation found no documented complications from incentive spirometry in the published literature. The only concerns raised were two theoretical ones: hyperventilation (from breathing too fast or too deeply) and barotrauma (pressure injury to the lungs), neither of which had been observed in clinical practice.3Respiratory Care. Complications of Mechanical Aids to Intermittent Lung Inflation
That review was published in 1982, and the decades since have not produced a wave of adverse event reports. This does not prove that incentive spirometry is safe in every clinical scenario, including acute PE. It does mean that the device has a remarkably benign track record across a wide range of patients, including many who were critically ill or had compromised cardiopulmonary function. If the device routinely caused hemodynamic crises or clot migration, some evidence of that would have surfaced by now.
The Broader Lesson From Early Ambulation
The same fear that makes clinicians hesitate about incentive spirometry after PE, that physical exertion might worsen the clot situation, also used to keep PE patients on strict bed rest. That practice has been largely abandoned. Multiple meta-analyses have shown that early ambulation in patients with acute deep vein thrombosis or pulmonary embolism, when combined with standard anticoagulation, does not increase the risk of new PE, clot progression, or death.
A meta-analysis published in PLOS ONE found that early ambulation was not associated with a higher incidence of new PE, DVT progression, or DVT-related death compared to bed rest. In patients with moderate or severe leg pain, early ambulation actually led to better pain outcomes.4PubMed Central. Bed Rest versus Early Ambulation with Standard Anticoagulation in The Management of Deep Vein Thrombosis: A Meta-Analysis A separate meta-analysis in the International Journal of Cardiology reached similar conclusions, finding no support for the systematic recommendation of bed rest as part of early management. Early ambulation showed a trend, though not a statistically significant one, toward fewer new PEs and lower overall mortality compared to bed rest.5International Journal of Cardiology. Bed rest or ambulation in the initial treatment of patients with acute deep vein thrombosis or pulmonary embolism: A findings update
Data from the large RIETE registry confirmed these findings and extended them, showing for the first time that bed rest did not reduce PE risk even in patients who presented with acute submassive PE.6PubMed. Bed rest or ambulation in the initial treatment of patients with acute deep vein thrombosis or pulmonary embolism: findings from the RIETE registry Walking around a hospital ward is far more hemodynamically demanding than taking slow, deep breaths with a plastic spirometer. If ambulation does not worsen outcomes, it becomes harder to argue that incentive spirometry would.
When Caution Genuinely Makes Sense
None of this means incentive spirometry is appropriate for every PE patient in every clinical moment. There are situations where extra caution is warranted, even without formal contraindication data.
Massive PE with hemodynamic instability is one such situation. When a patient’s right ventricle is acutely failing, blood pressure is dropping, and the team is considering thrombolysis or catheter-directed therapy, handing the patient an incentive spirometer is not a clinical priority and the theoretical hemodynamic concerns carry more weight. In these patients, even minor increases in venous return could be poorly tolerated.
Pulmonary infarction is another consideration. About 30% of acute PE cases result in pulmonary infarction, where the blocked artery leads to tissue death in the affected lung segment. This happens because after the pulmonary artery is occluded, bronchial arteries attempt to compensate, but the higher pressure in the bronchial circulation causes blood to leak into the alveoli. If the hemorrhage cannot be reabsorbed, the tissue dies.7Elsevier / Thrombosis Research. Pulmonary infarction in acute pulmonary embolism Patients with pulmonary infarction often have pleuritic chest pain, meaning pain that worsens with deep breathing. For these patients, the issue with incentive spirometry is less about hemodynamic danger and more about pain. Asking someone to take deep, sustained breaths when every inhalation feels like a knife in the chest is counterproductive. Adequate pain control has to come first, or the patient simply will not do it.
Severe hypoxemia in the acute phase is another practical barrier. A patient struggling to maintain oxygen saturation is not going to benefit from being coached on inspiratory volume targets. Stabilization comes before rehabilitation.
Pulmonary Rehabilitation After PE
Once a patient with PE is stabilized on anticoagulation and past the acute phase, the question shifts from “is it safe?” to “is it helpful?” Pulmonary embolism can leave lasting effects on exercise tolerance and breathing capacity, especially in cases complicated by right ventricular dysfunction or residual clot burden. A subset of patients develop chronic thromboembolic pulmonary hypertension, which significantly limits functional capacity.
Rehabilitation therapy, including breathing exercises, has been shown to improve recovery and prognosis in PE patients, though the evidence base is still small. A review in Experimental and Therapeutic Medicine noted the positive trajectory but cautioned that due to the small number of studies and short follow-up periods, the effectiveness and safety of pulmonary rehabilitation in PE require further investigation.8PubMed Central. Application of pulmonary rehabilitation in patients with pulmonary embolism
Incentive spirometry fits naturally into a rehabilitation program as one tool among several. It encourages slow, deep breathing, helps prevent atelectasis during periods of reduced mobility, and gives patients a visual target to work toward. For a post-PE patient who has been anticoagulated and is hemodynamically stable, the device offers a low-risk way to maintain or rebuild lung volume. In this context, withholding it based on a decades-old theoretical concern seems harder to justify than offering it with appropriate monitoring.
Why Compliance Matters More Than Contraindication
Ironically, the bigger practical problem with incentive spirometry is not danger but apathy. Patient compliance with prescribed IS protocols is notoriously poor. A systematic review covering cardiac, thoracic, and abdominal surgery patients found that actual spirometry performance was significantly lower than what was prescribed. Only about 17% of the trials in the review even reported on compliance, and those that did found it was far below target.9PubMed Central. Evidence regarding patient compliance with incentive spirometry interventions after cardiac, thoracic and abdominal surgeries: A systematic literature review
This is relevant for PE patients because the device is only useful if the patient actually uses it correctly and consistently. A spirometer sitting on the bedside table does nothing. For patients recovering from PE, especially those with pleuritic pain or anxiety about deep breathing, simply ordering the device is not enough. Respiratory therapists or nurses need to demonstrate technique, coach the patient through initial sessions, and adjust expectations based on pain levels and clinical status. The goal is sustained, comfortable inspiratory effort, not maximal forced breathing.
How Incentive Spirometry Compares to Other Breathing Techniques
Incentive spirometry is not the only way to achieve lung expansion. Deep breathing exercises, where a patient simply takes slow, deliberate breaths without a device, accomplish a similar physiological goal. Positive expiratory pressure (PEP) therapy, where the patient exhales against resistance, is another option that helps recruit collapsed lung regions from the expiratory side.
A randomized crossover study comparing incentive spirometry to PEP therapy in postoperative patients found that both techniques significantly improved ventilation and lung recruitment, with no meaningful difference between the two approaches.10PubMed. Incentive spirometry and positive expiratory pressure improve ventilation and recruitment in postoperative recovery: A randomized crossover study For PE patients who find deep inhalation painful, PEP therapy might be a more tolerable starting point, since the effort occurs during exhalation rather than inhalation. Coached deep breathing without any device at all is another option that avoids the compliance issues associated with equipment.
The choice between these techniques for a PE patient depends more on pain tolerance, clinical stability, and patient preference than on any evidence suggesting one is safer than another in this population. The underlying physiology they target, maintaining alveolar ventilation and preventing atelectasis, is the same regardless of the tool used.
The Evidence Gap That Keeps the Question Open
The honest answer to whether incentive spirometry is contraindicated in pulmonary embolism is that nobody has properly studied the question. There are no randomized trials examining incentive spirometry specifically in PE patients. There are no cohort studies tracking outcomes. There are no case series documenting adverse events. The contraindication label, to the extent it exists at all, rests on extrapolation from pulmonary function testing guidelines that were themselves based on expert opinion and have been criticized as outdated.
This matters because clinical decisions are being made every day based on this absence of evidence. Some respiratory therapy departments have internal protocols that withhold incentive spirometry for a set period after PE, often 24 to 72 hours. Others leave the decision to the ordering physician. Still others provide the device routinely to any patient at risk of atelectasis, including PE patients, without special restrictions. The variation reflects a field making its best guess without data to anchor to.
For researchers, this is a gap worth filling. A straightforward observational study tracking PE patients who receive incentive spirometry against those who do not, with outcomes including hemodynamic events, clot progression, and respiratory complications, would go a long way toward settling the question. Until that study exists, clinicians are left balancing a device with no documented complications against a theoretical concern that has never been validated, in a patient population that increasingly gets mobilized early and rehabilitated aggressively anyway.