What Does a Pulmonologist Do

A pulmonologist is a physician who specializes in the diagnosis and treatment of diseases affecting the respiratory tract — the lungs, bronchi, trachea, and associated structures. This page covers the full scope of a pulmonologist's clinical role, the mechanisms through which they evaluate and manage disease, the clinical scenarios that bring patients to their care, and the boundaries that distinguish pulmonology from adjacent medical and surgical specialties.

Definition and scope

Pulmonology is a subspecialty of internal medicine recognized by the American Board of Internal Medicine (ABIM). Physicians practicing in this field hold board certification in both internal medicine and pulmonary disease, with the pulmonary board certification examination administered by the ABIM following completion of accredited fellowship training.

The scope of a pulmonologist's practice spans 4 major disease domains:

1. Obstructive lung disease — conditions such as asthma, COPD, and bronchiectasis that reduce airflow through narrowed or damaged airways.
2. Restrictive and interstitial lung disease — including pulmonary fibrosis and occupational lung diseases that reduce lung volume and compliance.
3. Vascular and pleural disease — such as pulmonary embolism, pulmonary hypertension, and pleural effusion.
4. Sleep-disordered breathing — including sleep apnea and related conditions evaluated through formal sleep studies.

Infectious respiratory diseases — including pneumonia and tuberculosis — also fall within the pulmonologist's scope, particularly when they are severe, recurrent, or fail to resolve with standard primary care management.

The regulatory context for pulmonary medicine shapes how pulmonologists credential, document, and bill for services. Centers for Medicare & Medicaid Services (CMS) maintains specific evaluation and management (E/M) coding frameworks that govern how pulmonary consultations and follow-up visits are classified and reimbursed.

How it works

A pulmonologist's clinical workflow follows a structured sequence from initial assessment through diagnosis, treatment planning, and longitudinal management.

Diagnostic phase

The evaluation begins with a detailed history focused on symptom duration, occupational and environmental exposures, smoking history (quantified in pack-years), and prior respiratory diagnoses. Physical examination — including auscultation of breath sounds — is followed by objective testing. The core diagnostic tools pulmonologists deploy include:

• Pulmonary function tests (PFTs): spirometry, lung volume measurement, and diffusion capacity (DLCO) to classify and quantify impairment
• Chest X-ray and CT scan of the chest for structural and parenchymal assessment
• Arterial blood gas (ABG) analysis to evaluate gas exchange and acid-base status
• Bronchoscopy for direct airway visualization, biopsy, and lavage
• Sputum testing for microbiological and cytological evaluation
• Pulse oximetry for non-invasive oxygen saturation monitoring

The National Heart, Lung, and Blood Institute (NHLBI) publishes disease-specific clinical guidelines — including guidelines for asthma (the NAEPP Expert Panel Report) and COPD — that inform the diagnostic criteria pulmonologists apply.

Treatment phase

Treatment is guided by diagnosis, severity staging, and patient-specific factors. Pulmonologists prescribe inhaler therapy and medications for lung disease including bronchodilators, corticosteroids, antifibrotics, and targeted therapies. For hypoxemic patients, oxygen therapy is titrated to maintain arterial oxygen saturation above 88% — the threshold recognized by CMS for home oxygen qualification under the Local Coverage Determination framework.

Procedural interventions include thoracentesis for pleural fluid drainage, bronchoscopic interventions for endobronchial disease, and referral pathways for lung transplant evaluation when disease progresses to end stage.

Pulmonary rehabilitation programs — structured multidisciplinary regimens shown in NHLBI-cited evidence to reduce COPD-related hospitalizations — are coordinated through the pulmonologist's office or affiliated respiratory therapy departments.

Common scenarios

The clinical presentations that most frequently prompt pulmonology referral include:

• Persistent or unexplained dyspnea: Shortness of breath with uncertain cardiac versus pulmonary origin requires specialist-level evaluation to separate obstructive, restrictive, vascular, or deconditioning etiologies.
• Chronic cough: A chronic cough lasting more than 8 weeks — the threshold used in American College of Chest Physicians (ACCP) guidelines — warrants systematic evaluation for postnasal drip, asthma, GERD, and less common causes including fibrosis or malignancy.
• Abnormal imaging: An abnormal chest X-ray or CT finding such as a pulmonary nodule requires follow-up and, when indicated, lung cancer screening protocol enrollment. The U.S. Preventive Services Task Force (USPSTF) issued a Grade B recommendation for annual low-dose CT screening in adults aged 50–80 with a 20 pack-year smoking history.
• Recurrent respiratory infections: Bronchiectasis, immune deficiency, and structural abnormalities are evaluated when infections exceed 2 episodes per year requiring antibiotics.
• Wheezing and chest tightness: Differentiation between asthma, vocal cord dysfunction, and COPD requires objective lung function measurement rather than symptom history alone.
• Occupational lung disease: Exposures to silica, asbestos, coal dust, and organic antigens are regulated under OSHA's General Industry Standards (29 CFR 1910) and require pulmonologic surveillance and case documentation.

Decision boundaries

Pulmonology interfaces with 3 adjacent specialties, and the boundaries between them follow functional criteria.

Pulmonology vs. thoracic surgery: A pulmonologist diagnoses, stages, and medically manages lung disease; a thoracic surgeon operates. The decision to cross from medical management to surgical intervention — such as lung volume reduction surgery for severe emphysema or resection for early-stage non-small cell lung cancer — follows evidence-based criteria and typically requires multidisciplinary tumor board or procedural team input. The overlap zone is covered in detail at pulmonology vs. thoracic surgery.

Pulmonology vs. critical care: Pulmonologists who complete combined pulmonary critical care fellowship training manage mechanically ventilated patients in the ICU. Those without critical care training practice in outpatient or general inpatient settings only. This distinction affects scope of practice at the credentialing level and is hospital-specific.

Pulmonology vs. sleep medicine: Sleep-disordered breathing is managed by pulmonologists with sleep medicine competency, but sleep medicine is also practiced by neurologists and otolaryngologists. The ABIM and American Board of Sleep Medicine recognize overlapping board pathways.

Patients navigating where to start — including those who have not yet been referred — can review the conditions and symptoms covered across the pulmonaryauthority.com index to understand which presentations typically require specialist-level evaluation versus primary care management.

References

• American Board of Internal Medicine (ABIM) — Pulmonary Disease Certification
• National Heart, Lung, and Blood Institute (NHLBI) — Lung Diseases
• NHLBI — NAEPP Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma
• U.S. Preventive Services Task Force (USPSTF) — Lung Cancer Screening Recommendation
• American College of Chest Physicians (ACCP) — Clinical Practice Guidelines
• Centers for Medicare & Medicaid Services (CMS) — Local Coverage Determinations
• Occupational Safety and Health Administration (OSHA) — 29 CFR 1910 General Industry Standards

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