What are the objective criteria for weaning and extubating an adult intensive‑care patient on mechanical ventilation?

Extubation Weaning Criteria for Adult ICU Patients

Extubate adult ICU patients when they pass a 30-minute spontaneous breathing trial (SBT) using pressure support 5–8 cm H₂O with PEEP 5 cm H₂O, demonstrate adequate oxygenation (SpO₂ >90% on FiO₂ ≤0.40–0.50), maintain hemodynamic stability without vasopressors, show an awake mental status with intact airway reflexes, and have a rapid shallow breathing index (RSBI) ≤105 breaths/min/L. 1, 2

Daily Readiness Screening Criteria

Before attempting any weaning trial, verify that all of the following criteria are met:

• Resolution or marked improvement of the underlying condition that necessitated mechanical ventilation 1, 2
• Adequate oxygenation: FiO₂ <0.50 with SpO₂ >90%, PaO₂/FiO₂ ratio ≥200 1, 2
• Low ventilatory requirements: PEEP ≤5 cm H₂O, respiratory rate <30 breaths/min 1, 2
• Hemodynamic stability: no active myocardial ischemia, minimal or no vasopressor support 1, 2
• Adequate mental status: patient arousable and able to follow simple commands (open eyes, squeeze hand) 1, 2
• Intact airway reflexes with effective cough on suctioning 1, 2
• No new potentially serious conditions or planned procedures in the next 12–24 hours 1
• RSBI ≤105 breaths/min/L measured after 30–60 minutes of spontaneous breathing 1

Critical pitfall: Do not commence weaning when PaO₂ <55 mm Hg on FiO₂ ≥0.40, as the probability of weaning failure is markedly increased. 1

Conducting the Spontaneous Breathing Trial

Preferred SBT Method

Use pressure support ventilation (5–8 cm H₂O) with PEEP 5 cm H₂O rather than a T-piece for the initial SBT. 1, 2 This approach increases SBT success from 76.7% to 84.6% and extubation success from 68.9% to 75.4%, with a trend toward lower ICU mortality (8.6% vs 11.6%). 1

SBT Settings

• Pressure support: 5–8 cm H₂O 1, 2
• PEEP: 5 cm H₂O 1, 2
• FiO₂: ≤0.40 (40%) 1, 2
• Duration: 30 minutes for standard-risk patients; 60–120 minutes for high-risk patients 1, 2, 3

Rationale: The modest pressure support overcomes endotracheal tube resistance without masking readiness, while PEEP maintains alveolar recruitment and reduces work of breathing from intrinsic PEEP. 1 Most SBT failures occur within the first 30 minutes. 1, 2

SBT Failure Criteria (Stop Immediately If Any Occur)

• Respiratory distress: respiratory rate >35 breaths/min or increasing trend, accessory muscle use, abdominal paradox 1, 2
• Oxygen desaturation: SpO₂ <90% 1, 2
• Hemodynamic instability: heart rate >140 bpm or sustained increase >20%, systolic BP >180 mmHg or <90 mmHg 1, 2
• Altered mental status: increased anxiety, agitation, or diaphoresis 1, 2

Important: If an SBT fails, do not repeat the trial on the same day. 3 Focus on identifying and addressing reversible causes (fluid overload, cardiac dysfunction, inadequate secretion clearance) before attempting another trial the following day. 3

Pre-Extubation Assessment Beyond the SBT

A successful SBT does not guarantee successful extubation—approximately 10% of patients who pass an SBT will still fail extubation within 48 hours. 1, 2 Therefore, assess the following additional factors:

Upper Airway Patency (Cuff-Leak Test)

• Perform a cuff-leak test in patients with risk factors for laryngeal edema: female gender, nasal intubation, difficult/traumatic intubation, large endotracheal tube, high cuff pressures, or prolonged intubation (>7 days) 4, 2
• Positive test: absolute leak volume ≥110 mL or relative leak volume ≥10% 2
• If the test fails (low or absent leak), administer systemic corticosteroids (≈1 mg/kg prednisolone) at least 4–6 hours before extubation 4, 2

Airway Protection and Secretion Management

• Bulbar function: patient must be able to protect the airway 2
• Cough effectiveness: assess strength of cough on suctioning 1, 2
• Secretion load: evaluate volume and character of tracheal secretions 2

Weak cough or excessive secretions are independent risk factors for extubation failure and warrant consideration of prophylactic respiratory support. 2

Neuromuscular Function (If Applicable)

• Quantitative Train-of-Four (TOF) >90% to ensure adequate reversal of neuromuscular blockade 2

Risk Stratification for Post-Extubation Management

High-Risk Criteria for Extubation Failure

Patients are considered high-risk if they have any of the following:

• Age >65 years with multiple comorbidities 1, 2
• Cardiac failure as the primary cause of respiratory failure 1, 2
• APACHE II score >12 on the day of extubation 1
• Failure of more than one prior SBT 1, 2
• PaCO₂ >45 mm Hg after extubation or during the SBT 1, 2
• Presence of ≥1 comorbid condition (COPD, CHF) 1, 2
• Weak cough or excessive secretions 1, 2
• Prolonged mechanical ventilation (>14 days) 2
• Neurologic impairment or neuromuscular disease 2

Post-Extubation Strategy Based on Risk

Standard-Risk Patients

• Extubate directly to supplemental oxygen via face mask or nasal cannula 1
• Target SpO₂ 88–92% (particularly in patients with chronic hypercapnia) 1
• Monitor continuously for the first 24 hours: SpO₂, respiratory rate, work of breathing 1

High-Risk Patients

Apply prophylactic noninvasive ventilation (NIV) within 1 hour of extubation. 1, 2 This approach reduces:

• Re-intubation risk (RR 0.61; 95% CI 0.48–0.79) 1
• ICU mortality (RR 0.54; 95% CI 0.41–0.70) 1
• ICU length of stay by approximately 2.5 days 1

NIV settings: IPAP 10–12 cm H₂O, EPAP 5–10 cm H₂O, titrate FiO₂ to maintain SpO₂ 88–92% 1

Alternative for hypoxemic patients: High-flow nasal cannula (HFNC) lowers re-intubation rates to 4% versus 21% with conventional oxygen (P=0.01). 1

Known Difficult Airway

• Schedule extubation during daytime hours with experienced personnel immediately available 2
• Consider an airway exchange catheter left in place after extubation for patients at high risk of difficult re-intubation 2
• The catheter facilitates re-intubation within 10 hours and should be removed no later than 24 hours after placement 2

Protocol-Driven Weaning Approach

Implement a standardized weaning protocol led by respiratory therapists or nurses, with physician sign-off only for the final extubation decision. 1 This approach:

• Reduces total mechanical ventilation duration by approximately 25 hours 1
• Shortens ICU length of stay by approximately 1 day 1
• Increases overall weaning success rates 1

Definition of Successful Extubation

Extubation is considered successful when the patient does not require re-intubation or NIV within 48 hours post-extubation. 1, 2, 3 An extubation failure rate of 5–10% is acceptable in contemporary ICU practice. 4, 2

Critical Pitfalls to Avoid

• Do not delay extubation in patients who pass their first SBT, are <65 years, have normal PaCO₂, and lack significant respiratory or cardiac comorbidities—they rarely require prophylactic NIV 1
• Do not use SIMV for weaning—it is inferior to pressure support and T-piece methods 1, 3
• Do not rely solely on the SBT—screen for upper airway obstruction, ineffective cough, excessive secretions, swallowing disorders, and altered consciousness 4, 2
• Do not extubate patients still requiring vasopressors or with unresolved primary pathology 1
• Avoid premature weaning when using pressure-supported SBTs, as they may underestimate post-extubation work of breathing 3

Consequences of Extubation Failure

• Failed extubation is associated with 10–20% higher mortality compared with successful extubation 2, 5
• Up to 15% of ICU patients require re-intubation within 48 hours 2
• Post-extubation stridor occurs in 12–37% of extubations and accounts for approximately 15% of early re-intubations 2