What are the parameters for assessing a patient's readiness to be weaned from mechanical ventilation?

Answer

Numerous weaning parameters can be used to help predict successful extubation. However, no weaning protocol is 100% accurate in predicting successful weaning and extubation. These weaning parameters must be tailored for each clinical scenario.

For instance, if the rapid, shallow breathing index (the respiratory rate/tidal volume, or frequency/tidal volume [f/Vt]) is less than 105, the patient is likely to be weaned from mechanical ventilation. The investigators who derived this number examined primarily middle-aged patients. However, data from follow-up studies of patients older than 70 years suggest that a slightly higher rapid, shallow breathing index of less than 130 may be acceptable.

These parameters give no insight into whether a patient can protect his or her airway or clear secretions. Clinical judgment and experience play a large role in the physician's decision to withdraw mechanical ventilatory support. If a patient cannot be extubated and/or if the results of the rapid, swallow breathing test are not satisfactory, the reason for the failure must be evaluated and treated.

Parameters commonly used to assess a patient's readiness to be weaned from mechanical ventilatory support include the following:

Respiratory rate less than 25 breaths per minute
Tidal volume greater than 5 mL/kg
Vital capacity greater than 10 mL/k
Minute ventilation less than 10 L/min
PaO₂/FIO₂ greater than 200
Shunt (Qs/Qt) less than 20%
Negative inspiratory force (NIF) less than (more negative) -25 cm water
f/Vt less than 105, or less than 130 in elderly patients

Additionally, it has been reported that intercostal retraction after adding dead space may help in the detection of susceptibility to extubation failure.^[5]

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An example of the Drinker and Shaw negative-pressure ventilator (iron lung).
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The pressure, volume, and flow to time waveforms for airway pressure–release ventilation.

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Author

Christopher D Jackson, MD Faculty, Department of Internal Medicine, University of Tennessee Health Science Center College of Medicine-Memphis; Staff Physician, Christ Community Health Services; Staff Physician, Baptist Memorial Hospital

Christopher D Jackson, MD is a member of the following medical societies: American College of Physicians, Memphis Medical Society, National Medical Association, Southern Medical Association

Disclosure: Nothing to disclose.

Coauthor(s)

Muthiah P Muthiah, MD, FCCP, D-ABSM Associate Professor of Medicine, Division of Pulmonary and Critical Care and Sleep Medicine, Vice Chair for Internal Medicine (VA Academic Affairs), University of Tennessee Health Science Center College of Medicine; Director of Medical Intensive Care Unit (MICU), Memphis Veterans Affairs Medical Center

Muthiah P Muthiah, MD, FCCP, D-ABSM is a member of the following medical societies: American Academy of Sleep Medicine, American College of Chest Physicians, American Thoracic Society, Society of Critical Care Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Zab Mosenifar, MD, FACP, FCCP Geri and Richard Brawerman Chair in Pulmonary and Critical Care Medicine, Professor and Executive Vice Chairman, Department of Medicine, Medical Director, Women's Guild Lung Institute, Cedars Sinai Medical Center, University of California, Los Angeles, David Geffen School of Medicine

Zab Mosenifar, MD, FACP, FCCP is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, American Federation for Medical Research, American Thoracic Society

Disclosure: Nothing to disclose.

Additional Contributors

Ryland P Byrd, Jr, MD Professor of Medicine, Division of Pulmonary Disease and Critical Care Medicine, James H Quillen College of Medicine, East Tennessee State University

Ryland P Byrd, Jr, MD is a member of the following medical societies: American College of Chest Physicians, American Thoracic Society

Disclosure: Nothing to disclose.

Thomas M Roy, MD Chief, Division of Pulmonary Disease and Critical Care Medicine, Quillen Mountain Home Veterans Affairs Medical Center; Professor of Medicine, Division of Pulmonary Disease and Critical Care Medicine, Fellowship Program Director, James H Quillen College of Medicine, East Tennessee State University

Thomas M Roy, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, American Medical Association, American Thoracic Society, Southern Medical Association, Wilderness Medical Society

Disclosure: Nothing to disclose.

Acknowledgements

Gregg T Anders, DO Medical Director, Great Plains Regional Medical Command , Brooke Army Medical Center; Clinical Associate Professor, Department of Internal Medicine, Division of Pulmonary Disease, University of Texas Health Science Center at San Antonio

Disclosure: Nothing to disclose.

Oleh Wasyl Hnatiuk, MD Program Director, National Capital Consortium, Pulmonary and Critical Care, Walter Reed Army Medical Center; Associate Professor, Department of Medicine, Uniformed Services University of Health Sciences

Oleh Wasyl Hnatiuk, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and American Thoracic Society

Disclosure: Nothing to disclose.

Semaan Georges Kosseifi, MD Fellow in Pulmonary/Critical Care Medicine, East Tennessee State University

Disclosure: Nothing to disclose.

What are the parameters for assessing a patient's readiness to be weaned from mechanical ventilation?

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