Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate®

Weaning from mechanical ventilation: Readiness testing

Scott K Epstein, MD
Section Editor
Polly E Parsons, MD
Deputy Editor
Geraldine Finlay, MD


Discontinuing mechanical ventilation is a two-step process:

Readiness testing – During readiness testing, objective clinical criteria are evaluated to determine whether a patient is ready to begin weaning. Some clinicians also consider physiological tests, known as weaning predictors, because they are hesitant to begin weaning on the basis of clinical criteria alone. The clinical criteria and weaning predictors are defined and described below.

Weaning – Weaning is the process of decreasing ventilator support and allowing patients to assume a greater proportion of their ventilation. It may involve either an immediate shift from full ventilatory support to a period of breathing without assistance from the ventilator (ie, a spontaneous breathing trial [SBT]) or a gradual reduction in the amount of ventilator support [1,2]. Regardless of which approach is chosen, extubation is considered once the patient demonstrates the ability to breathe without the ventilator and both airway patency and airway protection have been assessed. (See "Extubation management".)

Readiness testing is reviewed here. Weaning and extubation are discussed separately. (See "Methods of weaning from mechanical ventilation" and "Extubation management".)


Readiness testing has two major purposes. The first is to identify patients who are ready to wean from mechanical ventilation. This is important because clinicians tend to underestimate the capacity of patients to breathe independently. Unnecessary mechanical ventilation needlessly increases the risk of complications related to mechanical ventilation.


Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Dec 2016. | This topic last updated: Tue Oct 20 00:00:00 GMT+00:00 2015.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Esteban A, Frutos F, Tobin MJ, et al. A comparison of four methods of weaning patients from mechanical ventilation. Spanish Lung Failure Collaborative Group. N Engl J Med 1995; 332:345.
  2. Brochard L, Rauss A, Benito S, et al. Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation. Am J Respir Crit Care Med 1994; 150:896.
  3. Esteban A, Anzueto A, Frutos F, et al. Characteristics and outcomes in adult patients receiving mechanical ventilation: a 28-day international study. JAMA 2002; 287:345.
  4. Funk GC, Anders S, Breyer MK, et al. Incidence and outcome of weaning from mechanical ventilation according to new categories. Eur Respir J 2010; 35:88.
  5. Epstein SK, Nevins ML, Chung J. Effect of unplanned extubation on outcome of mechanical ventilation. Am J Respir Crit Care Med 2000; 161:1912.
  6. MacIntyre NR, Cook DJ, Ely EW Jr, et al. Evidence-based guidelines for weaning and discontinuing ventilatory support: a collective task force facilitated by the American College of Chest Physicians; the American Association for Respiratory Care; and the American College of Critical Care Medicine. Chest 2001; 120:375S.
  7. Stroetz RW, Hubmayr RD. Tidal volume maintenance during weaning with pressure support. Am J Respir Crit Care Med 1995; 152:1034.
  8. Ely EW, Baker AM, Evans GW, Haponik EF. The prognostic significance of passing a daily screen of weaning parameters. Intensive Care Med 1999; 25:581.
  9. Hébert PC, Blajchman MA, Cook DJ, et al. Do blood transfusions improve outcomes related to mechanical ventilation? Chest 2001; 119:1850.
  10. Lai YC, Ruan SY, Huang CT, et al. Hemoglobin levels and weaning outcome of mechanical ventilation in difficult-to-wean patients: a retrospective cohort study. PLoS One 2013; 8:e73743.
  11. Netzer G, Dowdy DW, Harrington T, et al. Fever is associated with delayed ventilator liberation in acute lung injury. Ann Am Thorac Soc 2013; 10:608.
  12. Amoateng-Adjepong Y, Jacob BK, Ahmad M, Manthous CA. The effect of sepsis on breathing pattern and weaning outcomes in patients recovering from respiratory failure. Chest 1997; 112:472.
  13. Coplin WM, Pierson DJ, Cooley KD, et al. Implications of extubation delay in brain-injured patients meeting standard weaning criteria. Am J Respir Crit Care Med 2000; 161:1530.
  14. Beuret P, Roux C, Auclair A, et al. Interest of an objective evaluation of cough during weaning from mechanical ventilation. Intensive Care Med 2009; 35:1090.
  15. 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; 371:126.
  16. Krieger BP, Ershowsky PF, Becker DA, Gazeroglu HB. Evaluation of conventional criteria for predicting successful weaning from mechanical ventilatory support in elderly patients. Crit Care Med 1989; 17:858.
  17. Meade M, Guyatt G, Cook D, et al. Predicting success in weaning from mechanical ventilation. Chest 2001; 120:400S.
  18. Sahn SA, Lakshminarayan S. Bedside criteria for discontinuation of mechanical ventilation. Chest 1973; 63:1002.
  19. Multz AS, Aldrich TK, Prezant DJ, et al. Maximal inspiratory pressure is not a reliable test of inspiratory muscle strength in mechanically ventilated patients. Am Rev Respir Dis 1990; 142:529.
  20. Yang KL, Tobin MJ. A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med 1991; 324:1445.
  21. Sassoon CS, Mahutte CK. Airway occlusion pressure and breathing pattern as predictors of weaning outcome. Am Rev Respir Dis 1993; 148:860.
  22. Sassoon CS, Te TT, Mahutte CK, Light RW. Airway occlusion pressure. An important indicator for successful weaning in patients with chronic obstructive pulmonary disease. Am Rev Respir Dis 1987; 135:107.
  23. Montgomery AB, Holle RH, Neagley SR, et al. Prediction of successful ventilator weaning using airway occlusion pressure and hypercapnic challenge. Chest 1987; 91:496.
  24. Nemer SN, Barbas CS, Caldeira JB, et al. Evaluation of maximal inspiratory pressure, tracheal airway occlusion pressure, and its ratio in the weaning outcome. J Crit Care 2009; 24:441.
  25. Conti G, Montini L, Pennisi MA, et al. A prospective, blinded evaluation of indexes proposed to predict weaning from mechanical ventilation. Intensive Care Med 2004; 30:830.
  26. Jubran A, Tobin MJ. Pathophysiologic basis of acute respiratory distress in patients who fail a trial of weaning from mechanical ventilation. Am J Respir Crit Care Med 1997; 155:906.
  27. Vassilakopoulos T, Routsi C, Sotiropoulou C, et al. The combination of the load/force balance and the frequency/tidal volume can predict weaning outcome. Intensive Care Med 2006; 32:684.
  28. Vassilakopoulos T, Zakynthinos S, Roussos C. The tension-time index and the frequency/tidal volume ratio are the major pathophysiologic determinants of weaning failure and success. Am J Respir Crit Care Med 1998; 158:378.
  29. Fiastro JF, Habib MP, Shon BY, Campbell SC. Comparison of standard weaning parameters and the mechanical work of breathing in mechanically ventilated patients. Chest 1988; 94:232.
  30. Levy MM, Miyasaki A, Langston D. Work of breathing as a weaning parameter in mechanically ventilated patients. Chest 1995; 108:1018.
  31. Mohsenifar Z, Hay A, Hay J, et al. Gastric intramural pH as a predictor of success or failure in weaning patients from mechanical ventilation. Ann Intern Med 1993; 119:794.
  32. Hurtado FJ, Berón M, Olivera W, et al. Gastric intramucosal pH and intraluminal PCO2 during weaning from mechanical ventilation. Crit Care Med 2001; 29:70.
  33. Field S, Kelly SM, Macklem PT. The oxygen cost of breathing in patients with cardiorespiratory disease. Am Rev Respir Dis 1982; 126:9.
  34. Hubmayr RD, Loosbrock LM, Gillespie DJ, Rodarte JR. Oxygen uptake during weaning from mechanical ventilation. Chest 1988; 94:1148.
  35. Kemper M, Weissman C, Askanazi J, et al. Metabolic and respiratory changes during weaning from mechanical ventilation. Chest 1987; 92:979.
  36. Milic-Emili J. Is weaning an art or a science? Am Rev Respir Dis 1986; 134:1107.
  37. Delisle S, Francoeur M, Albert M, et al. Preliminary evaluation of a new index to predict the outcome of a spontaneous breathing trial. Respir Care 2011; 56:1500.
  38. Jabour ER, Rabil DM, Truwit JD, Rochester DF. Evaluation of a new weaning index based on ventilatory endurance and the efficiency of gas exchange. Am Rev Respir Dis 1991; 144:531.
  39. Nemer SN, Barbas CS, Caldeira JB, et al. A new integrative weaning index of discontinuation from mechanical ventilation. Crit Care 2009; 13:R152.
  40. Tanios MA, Nevins ML, Hendra KP, et al. A randomized, controlled trial of the role of weaning predictors in clinical decision making. Crit Care Med 2006; 34:2530.
  41. Ely EW, Bennett PA, Bowton DL, et al. Large scale implementation of a respiratory therapist-driven protocol for ventilator weaning. Am J Respir Crit Care Med 1999; 159:439.
  42. Laghi F, Cattapan SE, Jubran A, et al. Is weaning failure caused by low-frequency fatigue of the diaphragm? Am J Respir Crit Care Med 2003; 167:120.
  43. Ely EW, Baker AM, Dunagan DP, et al. Effect on the duration of mechanical ventilation of identifying patients capable of breathing spontaneously. N Engl J Med 1996; 335:1864.
  44. Kollef MH, Shapiro SD, Silver P, et al. A randomized, controlled trial of protocol-directed versus physician-directed weaning from mechanical ventilation. Crit Care Med 1997; 25:567.
  45. Burns KE, Meade MO, Lessard MR, et al. Wean earlier and automatically with new technology (the WEAN study). A multicenter, pilot randomized controlled trial. Am J Respir Crit Care Med 2013; 187:1203.
  46. Vitacca M, Clini E, Porta R, Ambrosino N. Preliminary results on nursing workload in a dedicated weaning center. Intensive Care Med 2000; 26:796.
  47. Miller MA, Krein SL, George CT, et al. Diverse attitudes to and understandings of spontaneous awakening trials: results from a statewide quality improvement collaborative*. Crit Care Med 2013; 41:1976.
  48. Burns KE, Lellouche F, Lessard MR. Automating the weaning process with advanced closed-loop systems. Intensive Care Med 2008; 34:1757.
  49. Rose L, Schultz MJ, Cardwell CR, et al. Automated versus non-automated weaning for reducing the duration of mechanical ventilation for critically ill adults and children. Cochrane Database Syst Rev 2013; :CD009235.
  50. Burns KE, Lellouche F, Lessard MR, Friedrich JO. Automated weaning and spontaneous breathing trial systems versus non-automated weaning strategies for discontinuation time in invasively ventilated postoperative adults. Cochrane Database Syst Rev 2014; :CD008639.
  51. Blackwood B, Burns KE, Cardwell CR, O'Halloran P. Protocolized versus non-protocolized weaning for reducing the duration of mechanical ventilation in critically ill adult patients. Cochrane Database Syst Rev 2014; :CD006904.