By Betty Tran, MD, MSc, Editor

Assistant Professor of Medicine, Pulmonary and Critical Care Medicine, Rush University Medical Center, Chicago

Dr. Tran reports no financial relationships relevant to this field of study.

SYNOPSIS: A cross-sectional, multinational survey of adult intensivists revealed significant regional variation in several weaning practices, including screening, weaning modes, techniques to conduct spontaneous breathing trials, the use of written directives, and use of non-invasive ventilation in the peri-extubation period.

SOURCE: Burns KEA, Raptis S, Nisenbaum R, et al. International practice variation in weaning critically ill adults from invasive mechanical ventilation. Ann Am Thorac Soc 2018;15:494-502.

The authors of this self-administered, cross-sectional survey of adult intensivists practicing in Canada, India, the United Kingdom, Europe, Australia/New Zealand, and the United States aimed to describe practice variation in several domains related to ventilator weaning. Survey participants were identified via the membership lists for various national critical care societies in set blocks of 300 per region. Participants received postal questionnaires with incentives to participate.

In total, 1,144 questionnaires were analyzed (Canada, 156; India, 136; United Kingdom, 219; Europe, 260; Australia/New Zealand, 196; United States, 177). Most respondents conducted once-daily screening for patient readiness to wean from the ventilator (70.0-95.6%), although this was reported most frequently in the United States, Canada, and India. Most survey respondents used either pressure support (PS) with positive end-expiratory pressure (PEEP; 56.5-72.3%) or T-piece (off the ventilator; 8.9-59.5%) to conduct a spontaneous breathing trial (SBT). Respondents from India (59.5%) and Europe (45.9%) used T-piece commonly, whereas it was used less frequently in the United States (8.9%), Australia/New Zealand (14.4%), and Canada (21.2%). Although directives for managing sedation were the most commonly used directives across all regions, many respondents reported receiving no written directives to guide care during weaning, particularly regarding managing delirium.

Only about one-third of respondents used the rapid shallow breathing index to decide to proceed with an SBT, and most did not use or consider a cuff leak test. There was significant variation regarding the use of noninvasive ventilation (NIV) for weaning and post-extubation in select subpopulations (e.g., chronic obstructive pulmonary disease, cardiogenic pulmonary edema, etc.).

Finally, there were notable regional differences in who was performing screening (respiratory therapists [RTs] in North America [78.5-87.2%] vs. nurses in the United Kingdom [57.5%] and Australia/New Zealand [44.4%]) and conducting SBTs (RTs in Canada and the United States; attending intensivists and senior trainees in India; and attending intensivists, senior trainees, and nurses in the United Kingdom, Europe, and Australia/New Zealand).

COMMENTARY

Current evidence supports several tenets related to ventilator weaning. Protocol-driven screening of patients for ventilator weaning readiness is associated with less time on the ventilator, more successful weaning, and cost savings.1,2 Generally, both T-piece and PS are recommended, although the former may underestimate a patient’s ability to breathe spontaneously and the latter may overestimate it.3,4 Multiple trials of SBTs likely are no more successful than once-daily trials.5 Protocols for ventilator and sedation liberation are recommended, given the associated reductions in duration of mechanical ventilation and/or ICU length of stay.6

Despite these recommendations, there is wide regional practice variation among intensivists, as reported in this cross-sectional survey. There are a few interesting findings to note from this study. Academic physicians were well-represented in this survey since survey respondents were identified through membership lists of various critical care societies. As such, there may have been even more practice variation seen if the survey had been extended to other physicians outside of this sampling method.

Second, the regions in which T-piece was employed frequently as an SBT technique (India, Europe) also were regions in which attending intensivists and senior trainees mainly were conducting the SBTs. In contrast, respiratory therapists are more involved in SBT screening and oversight in North America, where written directives on managing sedation, adjusting mechanical support, and conducting SBTs are more likely to be available, but where T-piece SBTs were used less frequently. Monitoring patients on a T-piece SBT tends to be more hands-on given the lack of ventilator alarms; it is unclear whether this variation is due to RT workload (in covering multiple patients off the ventilator on an SBT at the same time) and/or comfort in assessing extubation readiness apart from ventilator data.

Third, although critical care societies recommend written directives to guide care surrounding ventilator weaning, most regions had no directives, especially outside of North America. Finally, these regional differences may be related to broader differences in terms of educational systems and organization, readiness to adopt new practice guidelines, and the presence of external incentives and support; these details are not clear based on this study.

Overall, the results of this study are enlightening, especially when considering that there are some evidence-based best practice guidelines available concerning ventilator weaning. What will be more important in future studies is the effect, if any, that these regional variations in weaning practices have on actual patient outcomes.

REFERENCES

  1. Ely EW, Baker AM, Dunagan DP, et al. Effect on duration of mechanical ventilation of identifying patients capable of breathing spontaneously. N Engl J Med 1996;335:1864-1869.
  2. 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;25:567-574.
  3. Esteban A, Alia I, Gordo F, et al. Extubation outcome after spontaneous breathing trials with T-tube or pressure support ventilation. The Spanish Lung Failure Collaborative Group. Am J Respir Crit Care Med 1997;156:459-465.
  4. Ladeira MT, Vital FM, Andriolo RB, et al. Pressure support versus T-tube for weaning from mechanical ventilation in adults. Cochrane Database Syst Rev 2014 May 27;5:CD006056.
  5. Esteban A, Frutos F, Tobin MJ, et al. A comparison of four methods of weaning patients from mechanical ventilation. N Engl J Med 1995;332:345-350.
  6. Fan E, Zakhary B, Amaral A, et al. Liberation from mechanical ventilation in critically ill adults: An official ATS/ACCP Clinical Practice Guideline. Ann Am Thorac Soc 2017;13:441-443.