. 2022 Dec 20;163(5):1130–1143. doi: 10.1016/j.chest.2022.12.010

Table 2.

Pediatric Ventilator Liberation Operational Definitions

Topic	Definition
A.	Respiratory Support: respiratory support includes invasive mechanical ventilation and noninvasive respiratory support 1. Invasive mechanical ventilation (MV)⁵^,⁸^,⁹^,¹⁰^,¹¹^,¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹^,²⁰^,²¹^,²²^,²³^,²⁴^,²⁵^,²⁶^,²⁷^,²⁸^,²⁹^,³⁰^,³¹^,³²^,³³^,³⁴^,³⁵^,³⁶^,³⁷^,³⁸^,³⁹^,⁴⁰^,⁴¹^,⁴²^,⁴³^,⁴⁴^,⁴⁵^,⁴⁶^,⁴⁷^,⁴⁸^,⁴⁹^,⁵⁰: Positive pressure ventilation delivered via an artificial airway (ie, endotracheal tube [ETT] or tracheostomy tube) into the trachea. Noninvasive respiratory support (NRS): 2. Noninvasive ventilation (NIV)¹⁴^,¹⁵^,¹⁷^,¹⁹^,²⁶^,³²^,³⁴^,⁴¹^,⁴²^,⁴⁹: Positive pressure with variable levels of pressure delivered without an artificial airway via any interface which aims to provide an occlusive fit (eg, nasal mask, nasal pillows/prongs, full face mask or helmet). Examples include bi-level positive airway pressure or nasal high-frequency oscillation ventilation. 3. CPAP: Positive pressure with a single continuous distending pressure delivered without an artificial airway via any interface which aims to provide an occlusive fit (eg, nasal mask, nasal pillows/prongs, full face mask or helmet). 4. Negative pressure ventilation (NPV): A type of respiratory support in which the surface of the thorax and/or abdomen is exposed to sub-atmospheric pressure (ie, negative pressure). 5. High-flow nasal cannula (HFNC)¹⁹^,³²^,³⁹^,⁴⁰^,⁴⁹^,⁵⁰: Flow that is delivered through a heated humidified nasal cannula circuit and interface at a flow rate which is: • ≥ 1 L/kg/min for patients up to 10 kg • ≥ 10 L/min for patients above 10 kg When the HFNC flow falls below the above rates, the patient is considered to be receiving conventional oxygen therapy (see Definition 6). 6. Conventional oxygen therapy: In the context of defining liberation from respiratory support, conventional oxygen therapy is not considered a respiratory support. Conventional oxygen therapy is defined as the provision of > 0.21 oxygen by any of the following devices applied to a spontaneously breathing patient regardless of presence of humidification: d. Face mask oxygen delivered via any type of nonocclusive mask e. Nasal cannula at flow rates less than HFNC rates (see Definition 5) f. Tracheostomy collar without positive pressure
B.	7. Liberation from invasive MV⁸^,⁹^,¹⁰^,¹¹^,¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹^,²⁰^,²¹^,²²^,²³^,²⁴^,²⁵^,²⁶^,²⁷^,²⁸^,²⁹^,³⁰^,³¹^,³²^,³³^,³⁴^,³⁵^,³⁶^,³⁷^,³⁸^,³⁹^,⁴⁰^,⁴¹^,⁴²^,⁴³^,⁴⁴^,⁵³: A patient is considered to be liberated from invasive MV when: a. *ETT:* An ETT is removed and is not re-inserted within 48 h.∗ b. *Tracheostomy tube:* Positive pressure ventilation is no longer being delivered through a tracheostomy tube and is not re-initiated within 48 h.∗ This includes application of controlled, assisted, supported, or CPAP modes of positive pressure via a tracheostomy tube for any period during the day/night. ∗Excluding use for temporary procedures 8. Failed attempt to liberate from invasive MV (ie, extubation failure): a. *ETT:* Re-intubation within 48 h following extubation or a placement of a new tracheostomy with delivery of positive pressure ventilation for any period of the day.∗ b. *Tracheostomy tube:* Re-institution of positive pressure ventilation within 48 h after attempt of liberation from invasive mechanical ventilation.∗ This includes application of controlled, assisted, supported, or CPAP modes of positive pressure via a tracheostomy tube for any period during the day/night. ∗Excluding use for temporary procedures
C.	9. Liberation from respiratory support¹⁹^,⁴¹: A patient is considered liberated from respiratory support when the patient is no longer receiving invasive MV or NRS, and it is not re-initiated within 48 h.
D.	10. Duration of NRS¹⁰^,¹²^,¹³^,¹⁵^,¹⁹^,³⁰^,³³^,⁴¹: A measure of the total duration in which any of the NRS modes (Definitions 2-5) are applied. • If NRS is resumed > 48 h after an initial attempt to liberate from NRS, it is considered a new NRS course. • If one of the above NRS modes is re-initiated ≤ 48 h from an attempt to liberate from NRS, it is considered a failed liberation attempt, and the duration of NRS should include the time (≤ 48 h) that the patient was not receiving one of these therapies.
E.	11. Total duration of invasive MV⁸^,⁹^,¹⁰^,¹¹^,¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹^,²⁰^,²¹^,²²^,²³^,²⁴^,²⁵^,²⁶^,²⁷^,²⁸^,²⁹^,³⁰^,³¹^,³²^,³³^,³⁴^,³⁵^,³⁶^,³⁷^,³⁸^,³⁹^,⁴⁰^,⁴¹^,⁴²^,⁴³^,⁴⁴^,⁴⁵^,⁴⁶^,⁴⁷^,⁴⁸^,⁴⁹^,⁵⁰^,⁵¹^,⁵²: Time from initiation of invasive MV until successful liberation from invasive MV or death. • If invasive MV is resumed > 48 h after an initial attempt to liberate from invasive MV, it is considered a new ventilation course. • If invasive MV is resumed ≤ 48 h of an initial attempt to liberate from invasive MV, it is considered a failed liberation attempt, and the duration of invasive MV should include the time (≤ 48 h) that the patient was not receiving invasive MV.
F.	12. Spontaneous breathing trial (SBT): is defined as a systematic method of reduction of invasive MV support to predetermined settings to assess the likelihood that a patient will be able to independently maintain adequate minute ventilation and gas exchange without excessive respiratory effort if liberated from invasive MV. 13. Extubation readiness testing (ERT): is defined as a bundle of elements used to assess the patient’s eligibility to be liberated from invasive MV. In addition to the SBT, this may include factors such as assessment of sedation level, adequacy of neurologic control of the airway (ie, cough and gag), likelihood of post-extubation upper airway obstruction, assessment of respiratory muscle strength, magnitude of airway secretions, hemodynamic status, and a plan for post-extubation respiratory support.
G.	14. Twenty-eight ventilator-free days (VFDs-28): a. *For survivors:* equals 28 minus the sum of invasive MV days during the first 28 d after initiation of invasive MV. b. *For nonsurvivors:* VFDs-28 would be ZERO if death occurred within 28 d of initiation of invasive MV. If death occurs after 28 d, VFD-28 is calculated in the same way as for survivors.
H.	Planned vs rescue post-extubation NRS use⁹^,¹⁴^,³⁹^,⁴¹^,⁴⁹: 15. Planned: application of NRS (NIV, CPAP, NPV, or HFNC) which was planned to be initiated immediately after an attempt of liberation from invasive MV. 16. Rescue: application of NRS (NIV, CPAP, NPV, or HFNC) within 48 h after an attempt of liberation from invasive MV which was NOT planned prior to the invasive MV liberation attempt.