0
Correspondence |

Response FREE TO VIEW

Jonathon D. Truwit, MD, FCCP; Timothy D. Girard, MD; John P. Kress, MD, FCCP; Daniel R. Ouellette, MD, FCCP; Gregory A. Schmidt, MD, FCCP
Author and Funding Information

FINANCIAL/NONFINANCIAL DISCLOSURES: See earlier cited article for author conflicts of interest.

aDivison of Pulmonary and Critical Care Medicine, Froedtert and Medical College of Wisconsin, Milwaukee, WI

bDepartment of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA

cSection of Pulmonary and Critical Care, University of Chicago, Chicago, IL

dDepartment of Pulmonary Disease Service, Henry Ford Hospital, Detroit, MI

eDivision of Pulmonary Diseases, Critical Care and Occupational Medicine, University of Iowa, Iowa City, IA

CORRESPONDENCE TO: Jonathon D. Truwit, MD, FCCP, Ste C4000, Clinical Cancer Center, 9200 W Wisconsin Ave, Milwuakee, WI 53226


Copyright 2017, American College of Chest Physicians. All Rights Reserved.


Chest. 2017;151(5):1180-1181. doi:10.1016/j.chest.2017.02.027
Text Size: A A A
Published online

Regarding Dr Tobin’s first point, he correctly notes that we did not reference our statement “Moreover, weaning predictors such as maximal inspiratory pressure, static respiratory system compliance, and rapid/shallow breathing index lack sufficient positive and negative predictive value to make them routinely useful for judging patients’ ability to wean.” We do so now in the work by Meade et al. In support of our statement, we also reference a study in which Conti et al evaluated nine weaning parameters prospectively. Likelihood ratios for all weaning parameters ranged from 0.61 to 1.87, indicating only small, clinically unimportant changes in the posttest probability of success or failure. The authors applied Bayes’ theorem and concluded that all indexes were of little use in discriminating those who could be successfully weaned and those who would fail extubation. Consistent with our guideline, they concluded “…the systematic use of these weaning predictors is thus of little use clinically.”

The second critique relates to how to initiate the weaning process and expresses a concern that beginning with a spontaneous breathing trial (SBT) will prolong weaning unnecessarily. Our recommendation specifically addresses how to conduct an SBT once patients meet readiness criteria. The purpose of using readiness criteria, which some refer to as a safety screen, is to identify patients ready to be assessed with an SBT. We agree that readiness criteria are not meant to predict success during an SBT. Thus, readiness criteria, which we chose not to define, should not be overly restrictive. Indeed, a randomized controlled trial found that screening subjects receiving ventilation with f/Vt as part of the weaning algorithm delayed weaning by 1 day, a difference that was statistically significant. Moreover, use of f/Vt did not reduce the incidence of extubation failure, leading the authors to conclude that it should not be used routinely in weaning decision-making.

The third point relates to the sensitivity and specificity of SBTs, but Dr Tobin misstates our recommendation. We at no point make “explicit recommendations for weaning/extubation based on sensitivity/specificity of SBTs.” Our recommendation to use pressure augmentation was not based on sensitivity/specificity data but, rather, on clinical outcomes; that is, we made recommendations about how to conduct SBTs based on the outcomes observed in randomized trials. Dr Tobin is correct that determining sensitivity and specificity of SBT would require extubating subjects who fail the SBT. Perhaps not all intensivists would be comfortable with the ethics of conducting such a study, but this approach has been used in a pediatric population, with the following results: sensitivity, 95%; specificity, 37%; positive predictive value, 92%; and negative predictive value 50%.

We agree that pressure augmentation during the SBT reduces the work of breathing compared with work of breathing after extubation, during T-piece breathing, or during continuous positive airway pressure of 0 cm H2O. Regardless, it does not necessarily follow that conducting the SBT with pressure augmentation leads to premature extubation. Models limited to mathematical and physiologic data are not sufficient, as highlighted by data showing that pressure augmentation not only increases the likelihood of a successful SBT but also of successful extubation. Although complications associated with failed extubation are relevant, Dr Tobin fails to acknowledge the risks associated with prolonging mechanical ventilation.

We appreciate the opportunity to clarify our recommendations. Although we would welcome a stronger evidence base, we believe these guidelines reflect best practice based on current information.

References

Ouellette D.R. .Patel S. .Girard T.D. .et al Liberation from mechanical ventilation in critically ill adults: an official American College of Chest Physicians/American Thoracic Society clinical practice guideline: inspiratory pressure augmentation during spontaneous breathing trials, protocols minimizing sedation, and noninvasive ventilation immediately after extubation. Chest. 2017;151:166-180 [PubMed]journal. [CrossRef] [PubMed]
 
Meade M. .Guyatt G. .Griffith L. .Booker L. .Randall J. .Cook D.J. . Introduction to a series of systematic reviews of weaning from mechanical ventilation. Chest. 2001;120:396S-399S [PubMed]journal. [CrossRef] [PubMed]
 
Conti G. .Montini L. .Pennisi M.A. .et al A prospective, blinded evaluation of indexes proposed to predict weaning from mechanical ventilation. Intensive Care Med. 2004;30:830-836 [PubMed]journal. [CrossRef] [PubMed]
 
Tanios M.A. .Nevins M.L. .Hendra K.P. .et al A randomized, controlled trial of the role of weaning predictors in clinical decision making. Crit Care Med. 2006;34:2530-2535 [PubMed]journal. [CrossRef] [PubMed]
 
Chavez A. .dela Cruz R. .Zaritsky A. . Spontaneous breathing trial predicts successful extubation in infants and children. Pediatr Crit Care Med. 2006;7:324-328 [PubMed]journal. [CrossRef] [PubMed]
 
Sklar MC, Burns K, Rittayamai N, et al. Effort to breathe with various spontaneous breathing trial techniques. A physiological meta-analysis [published online ahead of print October 21, 2016].Am J Respir Crit Care Med.http://dx.doi.org/10.1164/rccm.201607-1338OC.
 
Esteban A. .Alía 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 [PubMed]journal. [CrossRef] [PubMed]
 

Figures

Tables

References

Ouellette D.R. .Patel S. .Girard T.D. .et al Liberation from mechanical ventilation in critically ill adults: an official American College of Chest Physicians/American Thoracic Society clinical practice guideline: inspiratory pressure augmentation during spontaneous breathing trials, protocols minimizing sedation, and noninvasive ventilation immediately after extubation. Chest. 2017;151:166-180 [PubMed]journal. [CrossRef] [PubMed]
 
Meade M. .Guyatt G. .Griffith L. .Booker L. .Randall J. .Cook D.J. . Introduction to a series of systematic reviews of weaning from mechanical ventilation. Chest. 2001;120:396S-399S [PubMed]journal. [CrossRef] [PubMed]
 
Conti G. .Montini L. .Pennisi M.A. .et al A prospective, blinded evaluation of indexes proposed to predict weaning from mechanical ventilation. Intensive Care Med. 2004;30:830-836 [PubMed]journal. [CrossRef] [PubMed]
 
Tanios M.A. .Nevins M.L. .Hendra K.P. .et al A randomized, controlled trial of the role of weaning predictors in clinical decision making. Crit Care Med. 2006;34:2530-2535 [PubMed]journal. [CrossRef] [PubMed]
 
Chavez A. .dela Cruz R. .Zaritsky A. . Spontaneous breathing trial predicts successful extubation in infants and children. Pediatr Crit Care Med. 2006;7:324-328 [PubMed]journal. [CrossRef] [PubMed]
 
Sklar MC, Burns K, Rittayamai N, et al. Effort to breathe with various spontaneous breathing trial techniques. A physiological meta-analysis [published online ahead of print October 21, 2016].Am J Respir Crit Care Med.http://dx.doi.org/10.1164/rccm.201607-1338OC.
 
Esteban A. .Alía 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 [PubMed]journal. [CrossRef] [PubMed]
 
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Find Similar Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543