What is an evidence‑based stepwise weaning protocol for an adult patient on invasive mechanical ventilation?

Evidence-Based Stepwise Weaning Protocol for Adult Patients on Invasive Mechanical Ventilation

Implement a structured protocol using daily readiness screening, spontaneous breathing trials with 5-8 cm H₂O pressure support (not T-piece), and risk-stratified post-extubation support to reduce mechanical ventilation duration by approximately 25 hours and ICU length of stay by 1 day. 1

Step 1: Daily Readiness Screening

Perform systematic daily assessment before attempting any weaning trial. The patient must meet all of the following criteria 1:

• Arousable and able to follow simple commands (open eyes, maintain eye contact, squeeze hand, stick out tongue, wiggle toes) 2
• Hemodynamic stability without vasopressor support or active myocardial ischemia 1
• Resolution or significant improvement of the primary condition requiring mechanical ventilation 3
• Adequate oxygenation: PaO₂/FiO₂ ratio ≥200 with PEEP ≤5 cm H₂O and FiO₂ ≤0.40 1
• Rapid shallow breathing index (RSBI) ≤105 breaths/min/L measured after 30-60 minutes of spontaneous breathing 1
• Intact cough on suctioning with minimal secretions or effective clearance mechanism 1

Critical pitfall to avoid: Do not attempt weaning when PaO₂ <55 mmHg on FiO₂ ≥0.40, as weaning failure probability is markedly increased 1

Step 2: Minimize Sedation

Before conducting the SBT 2:

• Implement daily sedation interruption or maintain light sedation targeting a level where the patient can follow commands 2
• This reduces mechanical ventilation duration by approximately 25 hours and ICU stay by 1 day compared to physician-discretionary sedation 2

Step 3: Conduct the Spontaneous Breathing Trial

SBT Technique (Critical Decision Point)

Use pressure support ventilation of 5-8 cm H₂O with PEEP 5 cm H₂O rather than T-piece for the initial SBT 3, 1, 2. This approach achieves:

• 84.6% SBT success rate versus 76.7% with T-piece 3, 1
• 75.4% extubation success versus 68.9% with T-piece 3, 1
• Trend toward lower ICU mortality (8.6% vs 11.6%) 3

SBT Settings 1:

• Pressure support: 5-8 cm H₂O
• PEEP: ≤5 cm H₂O
• FiO₂: ≤40%

SBT Duration 1, 4:

• Standard-risk patients: 30 minutes (most failures occur within this timeframe)
• High-risk patients: 60-120 minutes for improved predictive accuracy

Terminate SBT Immediately if Any of the Following Occur 1:

• Respiratory rate >35 breaths/min or increasing trend
• SpO₂ <90%
• Heart rate >140 bpm or sustained increase >20%
• Systolic blood pressure >180 mmHg or <90 mmHg
• Increased anxiety or diaphoresis
• Use of accessory muscles or abdominal paradox

If SBT fails: Resume full ventilatory support, identify and address reversible causes (fluid overload, cardiac dysfunction, secretion management), and do not repeat the SBT on the same day 4. Attempt the next SBT the following day after optimizing the patient's condition 4.

Step 4: Risk Stratification Before Extubation

Identify High-Risk Patients (Any ONE of the Following) 1, 2:

• Age >65 years with multiple comorbidities
• Chronic obstructive pulmonary disease or congestive heart failure
• Cardiac failure as primary cause of respiratory failure
• APACHE II score >12 on day of extubation
• Failure of more than one prior SBT
• PaCO₂ >45 mmHg during or after the SBT
• Weak cough or excessive secretions
• Prolonged mechanical ventilation (>14 days)
• Ineffective cough or impaired bulbar function

Perform Cuff Leak Test in Selected Patients 2:

For patients at high risk for post-extubation stridor (intubated >7 days, traumatic intubation, prolonged high cuff pressures):

• Conduct cuff leak test before extubation
• If test fails: Administer systemic corticosteroids at least 4 hours before extubation 2

Step 5: Extubation Strategy Based on Risk

High-Risk Patients 1, 2:

Extubate directly to prophylactic noninvasive ventilation (NIV) applied immediately after tube removal. This strategy achieves:

• Reduced reintubation (RR 0.61,95% CI 0.48-0.79) 1
• Reduced mortality (RR 0.54,95% CI 0.41-0.70) 1
• Shortened ICU stay by 2.48 days 1

NIV settings 1:

• IPAP: 10-12 cm H₂O
• EPAP: 5-10 cm H₂O
• FiO₂: Titrate to maintain SpO₂ 88-92%

Alternative for high-risk patients: High-flow nasal cannula (40-60 L/min) reduces reintubation rates to 4% versus 21% with conventional oxygen 1

Standard-Risk Patients 1:

• Extubate directly to supplemental oxygen via face mask or nasal cannula
• Target SpO₂ 88-92%

Critical pitfall to avoid: Do not use NIV as rescue therapy after post-extubation respiratory failure develops in high-risk patients; it must be applied prophylactically to achieve mortality benefit 2

Step 6: Post-Extubation Monitoring

Monitor continuously for the first 24 hours 1:

• SpO₂ (target 88-92%)
• Respiratory rate and work of breathing
• Use supplemental oxygen cautiously, particularly in patients with chronic hypercapnia, to avoid masking hypoventilation or atelectasis 1

Protocol Implementation

Personnel-driven execution: The weaning protocol should be carried out by respiratory therapists or nurses, with physician approval required only for the final extubation decision 1. This approach reduces total mechanical ventilation duration by approximately 25 hours and ICU length of stay by 1 day 1.

Classification of Weaning Difficulty 1:

• Simple weaning (70% of patients): Successfully pass first SBT and extubate on first attempt
• Difficult weaning (15% of patients): Require up to 3 SBTs or up to 7 days from first SBT
• Prolonged weaning (15% of patients): Require >3 SBTs or >7 days after first SBT

Target Extubation Failure Rate

Aim for 5-10% extubation failure rate (defined as reintubation or NIV requirement within 48 hours) 2. Rates >10% suggest inadequate readiness assessment; rates <5% may indicate overly conservative practices delaying liberation 4, 2.

Important caveat: Approximately 10% of patients who pass an SBT will still fail extubation, so comprehensive assessment beyond the SBT alone is essential 1, 4.