Predicting Post-Extubation Stridor
Abstract & Commentary
Jaber and colleagues report a series of 112 intubations of patients in their multidisciplinary ICU in Montpellier, France, during a 14-month period. Every ventilated patient underwent a cuff-leak test prior to extubation, and the incidence of post-extubation stridor was determined.
Jaber et al performed the cuff-leak test as follows: After oral and endotracheal suctioning and in the volume assist-control mode, the expired tidal volume is first measured with the endotracheal tube cuff inflated. The cuff is then deflated and the expiratory tidal volume determined by averaging 6-10 breaths. Cuff-leak volume is the difference between the 2 tidal volume measurements.
Twelve percent of the patients developed post-extubation stridor, a mean of 3.2 ± 3.3 h following extubation. Extubation failure (ie, the need to reintubate the patient within 48 hours of extubation) occurred in 11/112 (10%) patients, of whom 9 developed stridor (P < 0.001 for occurrence of stridor in patients requiring reintubation).
Jaber et al then constructed receiver operating characteristic curves plotting the true- and false-positive rates of post-extubation stridor as a function of cuff-leak volume. They found that when thresholds of 130 mL leaked volume and 12% of the pre-cuff-deflation volume were used as a cut-off, the positive and negative predictive values for the cuff-leak test in predicting post-extubation stridor were 85% and 95%, respectively. Thus, a low cuff-leak volume measured before extubation permits the identification of patients at increased risk for developing post-extubation stridor, and post-extubation stridor is a strong predictor of the need to reintubate the patient. The occurrence of post-extubation stridor was associated with an increased severity of illness as assessed by SAPS II, with having a medical (as opposed to a surgical) reason for admission to the ICU, with a history of self-extubation, and with a prolonged period of intubation. (Jaber S, et al. Post-extubation stridor in intensive care unit patients: Risk factors evaluation and importance of the cuff-leak test. Intensive Care Med. 2003;29:69-74.)
Comment by David J. Pierson, MD
Should patients who develop stridor following endotracheal tube removal be reintubated? If the clinician’s answer to this is an automatic "yes," the results of this study shed little light on the still poorly lit corner of critical care occupied by weaning and extubation. Jaber et al showed that if patients developed stridor they were almost always reintubated. However, this study shows us more than that. It shows that patients with a low cuff-leak volume (< 130 mL or < 12% of pre-cuff-deflation expired tidal volume) are at increased risk for development of post-extubation stridor and subsequent reintubation. It reiterates the importance of assessing upper airway function in addition to gas exchange and ventilatory mechanics in deciding when to extubate a patient following an episode of acute respiratory failure. Clinicians usually think of weaning and extubation together, and in most cases this works. However, there are patients who can be liberated from ventilatory support who still need airway protection, just as there are patients who can be extubated but still need ventilatory support, at least part of the time.
This study emphasizes the fact that the decision to extubate a patient who otherwise seems ready for ventilator weaning should include consideration of airway patency following extubation, and reminds us that at least semi-quantitative tests are available for evaluating upper airway function in this setting.
Dr. Pierson is Professor of Medicine University of Washington Medical Director Respiratory Care Harborview Medical Center Seattle.
Jaber and colleagues report a series of 112 intubations of patients in their multidisciplinary ICU in Montpellier, France, during a 14-month period. Every ventilated patient underwent a cuff-leak test prior to extubation, and the incidence of post-extubation stridor was determined.Subscribe Now for Access
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