The information on this website is not intended for diagnosis or treatment. Please consult your physician for health concerns.

+90 850 321 50 00

SBT — Spontaneous Breathing Trial and Ventilator Liberation Protocol

Structured protocol for evaluating readiness for extubation in mechanically ventilated patients.

Written by: Saygı Hospital Health Guide Editorial Board
Published: · Last updated:

This content is for general information; please consult your physician for diagnosis and treatment.

References (2)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Göğüs Hastalıkları department. Book Appointment →

What is SBT — Spontaneous Breathing Trial and Ventilator Liberation Protocol?

A Spontaneous Breathing Trial (SBT) is the standard daily test used to determine whether a mechanically ventilated patient is ready to be liberated from ventilatory support. Successful completion of an SBT is followed by consideration of extubation.

SBT should be preceded by daily interruption of sedation (SAT — Spontaneous Awakening Trial). Combining SAT with SBT (the ABC trial — Awakening and Breathing Coordination) shortens ventilator duration by up to three days and reduces ICU and hospital mortality (ABC Trial, Lancet 2008).

SBT formats include T-piece (zero support, most physiologic but tiring), low pressure support (PS 5-8 / PEEP 5 — most common and comfortable), and CPAP 5 (with PEEP). Duration is 30-120 minutes; a 30-minute SBT is as effective as longer trials.

Weaning groups: Simple (successful at first SBT — 70%), Difficult (successful within 2-7 days), and Prolonged (>7 days or 3+ failed SBTs — 15%). Prolonged weaning requires critical-care rehabilitation, tracheostomy, and a multidisciplinary approach.

Symptoms

Weaning readiness criteria — underlying process resolved, PaO2/FiO2 >200 with FiO2 <0.5, PEEP ≤8, hemodynamic stability (low or no vasopressor), afebrile, and adequate mental status
SBT failure criteria — SaO2 <90%, respiratory rate >35, tachycardia >140, SBP >180 or <90, diaphoresis, anxiety, or mental-status decline
Rapid Shallow Breathing Index (RSBI) = RR/Vt(L); <105 favors success, >105 increases the likelihood of weaning failure
Cuff-leak test — predicts post-extubation stridor; a leak <110 mL should prompt considering steroid prophylaxis
Airway clearance (cough strength, secretion burden) — weak cough + high secretions + altered consciousness predict extubation failure

Risk Factors

Prolonged mechanical ventilation (>7 days) — muscle atrophy, diaphragmatic dysfunction
Age >65, chronic heart or lung disease, obesity
ICU-acquired weakness (critical-illness polyneuropathy–myopathy)
Post-severe ARDS (prolonged need for high PEEP)
Psychological dependence (anxiety, delirium — should be addressed with SAT)

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Daily SBT assessment should begin from the 24-48th hour of mechanical ventilation
  • Failed SBT — investigate the cause (pulmonary, cardiac, neurological, airway, secretions) and repeat after 24 hours
  • 3+ failed SBTs or >7 days of ventilation → prolonged-weaning protocol and tracheostomy evaluation

Treatment Methods

01
Readiness assessment — if SAT (sedation off), hemodynamics, oxygenation, and respiratory-mechanics criteria are met, initiate SBT
02
SBT — 30-120 minutes on PS 5/PEEP 5 or T-piece; respiratory, hemodynamic, and mental-status monitoring by nursing and respiratory therapy
03
Extubation after a successful SBT — deflate cuff, have the patient cough, remove the tube; close observation in the first 24 hours (highest reintubation risk)
04
Failed SBT — rest on ventilator (restore pressure support), investigate the cause, and retry after 24 hours
05
Prolonged weaning — early tracheostomy (>10-14 days), physiotherapy plus mobilization, nutritional optimization, delirium management
06
Noninvasive ventilation (NIV) can be used prophylactically after extubation in high-risk patients (COPD, obesity, cardiac)

Which Department to Visit?

You can visit our Göğüs Hastalıkları department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Göğüs Hastalıkları Department

Let us help you

You can make an appointment with our specialists or contact us for your concerns.

Book AppointmentContact Us

Related Health Topics

Other articles from the same department you may want to explore.

Asthma

Göğüs Hastalıkları

Asthma is characterized by wheezing, coughing and shortness of breath attacks; with proper treatment it can be kept under control.

COPD (Chronic Obstructive Pulmonary Disease)

Göğüs Hastalıkları

COPD is an irreversible lung disease characterized by shortness of breath and chronic cough; quitting smoking slows its progression.

Pneumonia

Göğüs Hastalıkları

Pneumonia presents with high fever, cough and shortness of breath; the vast majority recover with appropriate antibiotic treatment.

Tuberculosis (TB)

Göğüs Hastalıkları

Tuberculosis presents with weeks-to-months of cough, fever, and night sweats; early diagnosis and treatment lead to full recovery.

Pleural Effusion

Göğüs Hastalıkları

Pleural effusion is the accumulation of excess fluid in the pleural space, resulting from imbalances in fluid production and removal, and represents a manifestation of diverse cardiopulmonary, infectious, and malignant disorders.

Pneumothorax

Göğüs Hastalıkları

Pneumothorax is the presence of air in the pleural space resulting in partial or complete lung collapse, classified as spontaneous (primary/secondary), traumatic, or iatrogenic, with tension pneumothorax representing a life-threatening emergency.

Bronchitis (Acute and Chronic)

Göğüs Hastalıkları

Acute bronchitis is mostly viral and resolves spontaneously, while chronic bronchitis is a smoking-related component of COPD.

Bronchiectasis

Göğüs Hastalıkları

Bronchiectasis is a chronic respiratory disease characterized by permanent, abnormal dilation of bronchi with associated destruction of muscular and elastic components of airway walls, resulting in impaired mucociliary clearance and recurrent infection.

Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.