Ventilator Weaning and Liberation

Educational Objectives

The goal of this program is to improve the discontinuation of mechanical ventilation. After hearing and assimilating this program, the clinician will be better able to:

1. Optimize weaning and liberation from mechanical ventilation.

Summary

Mechanical ventilation: needed in ≈90% of critically ill patients; prolonged ventilation results in complications in 27% of patients on ventilators; plan for weaning should start immediately after initiating ventilation; 75% of mechanically ventilated patients can be discontinued abruptly; use the most physiologic mode of ventilation to avoid complications

Weaning: the process of gradually reducing the level of ventilatory support for extubation; by contrast, discontinuation is extubation and spontaneous ventilation; some patients can be extubated on the first attempt; difficult weaning involves spontaneous breathing trials (3 or 4) for ≤7 days for a successful extubation; prolonged weaning refers to failed spontaneous breathing trials ≤7 days; clinicians are very conservative in liberating patients from ventilation

Barriers to extubation: include delirium, prolonged sedation, oversedation, pneumonia, and intensive care unit (ICU)-induced weakness; 25% of patients on ventilator experience ventilator-induced diaphragmatic dysfunction arising from disuse atrophy; pressure support ventilation (PSV) helps decrease diaphragmatic dysfunction

Methods of weaning: include assist-control ventilation, synchronous intermittent mandatory ventilation (SIMV), T-piece technique trials, and PSV (decreases pressure support); PSV is the most effective method of weaning; parameters for weaning, including negative inspiratory pressure, vital capacity, and tidal volume, are not helpful as predictors of extubation (accuracy, 52%; false-negative rate, 45%); weaning is not extubation; PSV involves gradual reduction of pressure support (by 2-4 mm Hg) to 8 cm of water; SIMV is the least effective method for weaning and is not recommended; PSV — with decreasing pressure support, the left ventricular volume increases, leading to ventricular failure in susceptible patients (PSV decreases the intrathoracic pressure and increases pulmonary flow); B-type natriuretic peptide (BNP) can be used to assess cardiac function (optimal, marginally low BNP); venous oxygen saturation and echocardiography are effective guides

Optimization: optimize patients by controlling sepsis, discontinuing benzodiazepines (ideally, should not be used), and improving mobility; optimize sedation prior to weaning trials; Balas et al (2014) emphasized the need for an awake patient for extubation (applies to all patients on a ventilator); 76% of patients can be successfully liberated from the ventilator

Spontaneous awakening trial (SAT): involves discontinuing sedation and analgesics; dexmedetomidine (eg, Dexdor, Igalmi, Precedex) is a safe and effective sedative that can be continued during extubation; if SAT is not successful, restart sedation at half the dose; data show that dexmedetomidine did not affect the length of stay in the ICU but reduced delirium and the duration on ventilator; if SAT is successful, proceed to spontaneous breathing trial (SBT), which evaluates whether the patient can stay off the ventilator successfully

Spontaneous breathing trial: no role for weaning parameters; extubation is considered successful if the patient does not need the ventilator for 72 hr; after a safety screen, proceed with SBT; can be performed using a T-piece (connected to the endotracheal tube; do not exceed 30 min) or PSV (8/5 for 30-90 min; the preferred method); do not exceed the time limit as the patient will get tired and cannot be extubated; data show that 30 min for PSV is adequate; criteria for failure include respiratory rate >35 breaths/min or <8 breaths/min, elevated intracranial pressure, agitation, and <88% oxygen on pulse oximetry; a recent Cochrane review (Ladeira et al [2018]) showed that PSV is more effective than the T-piece technique in evaluating a patient for extubation; PSV decreases the work of breathing and overcomes the resistance in the T-tube

Take-home points: SAT/SBT is effective; Girard et al (2008) showed reduction in mortality and morbidity, faster liberation from ventilation, decrease in length of stay, and decrease in complications with SAT/SBT; however, only 20% to 25% of ICUs have employed SAT/SBT protocol

Readings

Balas MC, Vasilevskis EE, Olsen KM, et al. Effectiveness and safety of the awakening and breathing coordination, delirium monitoring/management, and early exercise/mobility bundle. Crit Care Med. 2014;42(5):1024-1036. doi:10.1097/CCM.0000000000000129; Girard TD, Kress JP, Fuchs BD, et al. Efficacy and safety of a paired sedation and ventilator weaning protocol for mechanically ventilated patients in intensive care (Awakening and Breathing Controlled trial): a randomised controlled trial. Lancet. 2008;371(9607):126-134. doi:10.1016/S0140-6736(08)60105-1; Heybati K, Zhou F, Ali S, et al. Outcomes of dexmedetomidine versus propofol sedation in critically ill adults requiring mechanical ventilation: a systematic review and meta-analysis of randomised controlled trials. Br J Anaesth. 2022;129(4):515-526. doi:10.1016/j.bja.2022.06.020; Ladeira MT, Vital FMR, Andriolo RB, et al. Pressure support versus T-tube for weaning from mechanical ventilation in adults. Cochrane Database Syst Rev. 2014;2014(5):CD006056. doi:10.1002/14651858.CD006056.pub2.

Disclosures

For this program, the following relevant financial relationships were disclosed and mitigated to ensure that no commercial bias has been inserted into this content: Dr. Kaplan is on the Speaker's Bureau of 3M/KCI. Members of the planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Kaplan was recorded at Mattox Vegas Trauma, Critical Care & Acute Care Surgery 2023, held March 27-29, 2023, in Las Vegas, NV, and presented by Trauma and Critical Care Foundation. For more information about upcoming CME activities from this presenter, please visit https://www.trauma-criticalcare.com. Audio Digest thanks the speakers and Trauma and Critical Care Foundation for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.50 CE contact hours.

Lecture ID:

GS712104

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.