Extubation

• Just as important as knowing when and how to put a patient on a ventilator:
  • It is important to know when and how to remove them from this support:
    • Also known as “weaning
• An adage from Critical Care is that preparation for extubation:
  • Starts as soon as the patient is intubated
• With COVID-19:
  • The patients are generally requiring prolonged periods of intubation:
    • With many reports quoting 10 to 14 days
• Regardless, the onus falls on the clinicians caring for any mechanically ventilated patient to assess the patient’s daily for signs of stability or improvement:
  • With any signs of improvement, assessment for extubation readiness should begin
• Patients’ conditions should be assessed continually:
  • And once gas exchange and compliance improve:
    • The level of support can be reduced
• For most patients, the first step in moving towards extubation readiness is:
  • To move from assist control ventilation to pressure support ventilation:
    • Pressure support ventilation:
      • Allows for spontaneous ventilation
        • The patient engages their diaphragm and sets their own respiratory rate, flow, and tidal volume
• The following ventilator screen illustrates a patient who is ready to be changed to pressure support:
  • The patient was arousable with:
    • Lightening sedationhas
    • Has good pulmonary mechanics as indicated by:
      • The low PIP of only 22 with a TV of 400, has a low PEEP requirement, and is only on 50% FiO2
  • On these settings, the patient’s ABG was also reassuring, at 7.37/38/110:
    • Note:
      • In addition to changing to pressure support, the FiO2 could also be decreased to 40% given the more than adequate PaO

• Once the patient has been placed on pressure support:
  • Physiological measurements including:
    • MIP (maximal inspiratory pressure),
    • frVt (respiratory frequency to tidal volume ratio, or
    • Rapid shallow breathing index
      • and others can be used to assess a patient’s readiness to wean
• If the following criteria are met:
  • The patient should undergo a spontaneous breathing trial (SBT) to determine if they are ready to attempt extubation

• Criteria for Performing Spontaneous Breathing Trial:
  • Improvement of underlying condition that led to intubation
  • Relative hemodynamic stability
    • HR < 130 beast per minute
    • Mean arterial pressure (MAP):
      • Adequately supported on a stable dose of vasopressors
    • Presence of a cough reflex:
      • Often elicited by suctioning
    • Burden of secretions that can be handled by cough strength:
      • Patients with a robust cough will be able to clear more secretions
    • Adequate oxygenation:
      • Usually SpO2 > 90% on 40% FiO2 and PEEP ≤ 8
    • Ability to maintain the current oxygenation status once extubated
    • Adequate ventilation:
      • pH > 7.3 with a PCO2 near baseline
      • Minute ventilation that a patient can maintain after extubated:
        • Usually < 12 L/min
    • Minimal ventilator settings:
      • On pressure support ≤ 10 cmH2O
      • On PEEP ≤ 8 cmH2O
      • Maintaining tidal volumes ≥ 5 mL/kg PBW
      • Respiratory rate < 35
      • FiO2 ≤ 50%

• The following screen shows a patient on pressure support, 10/5 (10 cm H20 driving pressure over 5 cm H2O of PEEP):
  • This patient is marginal, as the tidal volume with 10 cm H2O of driving pressure is 400, which is acceptable, but the respiratory rate is 30:
    • The patient should be assessed for non-pulmonary causes of tachypnea:
      • Such as pain, anxiety/agitation, fever, etc
    • It is reasonable to decrease the pressure support of 10 cm H2O and reassess both the tidal volumes and respiratory rate
    • It is difficult to predict how patients will do; often the best course is to give them a trial and assess

• Spontaneous breathing trials are used to:
  • Assess a patient’s readiness to wean by removing ventilation support for 30 minutes and evaluating the patient’s ability to breathe on their own during this time
  • There are many ways to perform SBTs, including:
    • Pressure support of 5/5, 0/5, and 0/0, as well as “T-piece trials” in which the patient is taken off the ventilator and supported with blow-by humidified oxygen
    • Each approach has its proponents, and institutional guidelines vary
      • The most important concept to consider is the available respiratory support options once the patient is intubated, and ensure they are able to pass with that level of support

• Criteria for Passing Spontaneous Breathing Trials:
  • Clinical Appearance:
    • No evidence of respiratory distress:
      • Cyanosis
      • Diaphoresis
      • Accessory muscle use
      • Grimacing
  • Pulmonary mechanics
    • Ratio of respiratory rate : tidal volume:
      • Less than 105
    • Respiratory rate less than 30 breaths per minute
    • Tidal volume less than 5 mL/kg PBW
  • Oxygenation and ventilation:
    • SpO2 ≤ 50%
    • PaC02 ≤ 50mmHg or a
    • pH ≥ 7.3 or decrease in pH of ≤ 0.07
  • Hemodynamics:
    • Change in SBP to > 90 or < 180 mmHg
    • HR < 130 beats per minute
    • New dysrhythmias
• The screen below demonstrates a patient who is doing well on an SBT:
  • They are on pressure support, 5/5, and have large tidal volumes of 735 mL, indicating good compliance
  • They are breathing at a slow rate of 14, and they are on a low FiO2 of 25%
  • This patient would be an excellent candidate for extubation, assuming there are no other barriers

• If a patient’s spontaneous breathing trial is successful, the next step is to assess for other barriers to extubation
• A helpful approach is to go head to toe:
  • Head:
    • Is the patient awake, following commands?
      • If not, does the clinician believe s/he will be able to cough and protect the airway?
    • Is the patient calm or agitated?
      • If agitated, does it seem related to the ETT?
      • Is there a plan for agitation management?
    • Is pain adequately controlled without inducing somnolence or apnea?
• Face/Neck:
  • Any facial trauma?
    • Tongue or lip swelling?
      • Note:
        • This may be seen in a patient who was previously proned
  • Was the patient a difficult intubation?
    • Note:
      • Does not preclude extubation, but all clinicians should be aware
  • Does the patient have a cuff leak?
• Chest:
  • Does the patient have any chest trauma/other pathology (eg, rib fractures, etc) that may preclude adequate breathing?
• Abdomen:
  • Any planned procedures or diagnostics that should happen before extubation?
  • What is the nutrition plan after extubation?
  • Should an NG tube be placed for tube feeds before extubation?
    • Note:
      • Most patients with prolonged intubations have oropharyngeal muscle weakness for days after extubation, precluding normal feeding
• If there are no barriers to extubation, the patient may be extubated:
  • In preparation, gather supplies that would be needed for oxygenation post-extubation (nasal cannula, oxygen mask, CPAP or BPAP, etc.), as well as supplies that would be needed to intubate the patient again if extubation fails:
    • Endotrachial tubes (ETTs) of appropriate sizes
    • Bag mask with positive end expiratory-pressure (PEEP) valve
    • Airway bougies
    • Tube exchangers
    • Traditional direct laryngoscope
    • Video laryngoscope
    • Flexible bronchoscope
    • Drugs needed for induction
    • Suction catheter
• For extubation:
  • Put the patient in an upright, seated position
  • Suction the ETT and oral cavity
  • Remove all secretions above the ETT cuff using subglottic suction, if available, or insert a small bore catheter on the side of the ETT for removal of secretions above the ETT cuff
  • Remove the ETT from the holder
  • Ask the patient to take a deep breath and exhale
  • During exhalation, deflate the cuff and smoothly remove the ETT
    • Note:
      • If an orogastric tube is present, it will be removed alongside the ETT and may need to be replaced by a nasogastric tube, if the patient is not ready for oral intake of medications and nutrition
  • Suction the oral cavity
  • Ask the patient to take a deep breath and cough out all secretions
  • Provide supplemental oxygen through a nasal cannula, oxygen mask, etc., as appropriate
  • After extubation, it is important to monitor the patient carefully:
    • Make sure they have adequate oxygenation and provide supplemental oxygen as appropriate
    • If necessary, consider CPAP/BPAP if a patient requires additional support
    • Use bronchodilators as needed, provide secretion management, maintain airway hydration and patent central airway, and encourage patient behaviors that reduce the potential for re-intubation:
      • Coughing
      • Deep breathing
      • Sitting up
      • Moving around if appropriate
• Risk factors that suggest a patient will need to be re-intubated include:
  • Pneumonia
  • Weak cough
  • Frequent suctioning
  • Rapid shallow breathing index > 58 breaths per minute per liter
  • Positive fluid balance in the 24 hours prior to extubation

Extubation process and post-extubation recommendations modified from Saeed F, Lasrado S. Extubation. [Updated 2019 Jul 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539804/

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