The recent success of a pilot study on the cuff leak test, which may impact patient extubation procedures, supports the feasibility of a larger trial. The COMIC trial, which included 100 critically ill patients in three countries, was the first of its kind to examine use of the cuff leak test prior to extubation and its effects on patient outcomes.
Tracheal intubation, commonly known as a “breathing tube,” is indicated for critically ill patients experiencing low blood oxygen and other conditions. It is most often performed under general anesthesia due to the invasive and uncomfortable nature of the procedure. Removal of this tube, known as extubation, is also a delicate procedure.
The cuff leak test can be used by intensivists to help guide extubation. During this test, the cuff at the end of the breathing tube is deflated and the respiratory therapist or physician listens for air passing around the tube. If no air passage is heard, the larynx is presumed to be swollen and blocking airflow. This swelling is often treated with steroids and a delay in extubation to avoid an airway obstruction.
While the cuff leak test is non-invasive and inexpensive, it can be inaccurate.
“A false positive test – indicating the presence of laryngeal edema [swelling] when none exists – may result in an unnecessary delay in extubation, exposure of the patient to systemic steroids, and increase a patient’s risk of deconditioning,” said Dr. Kimberley Lewis, lead author of the COMIC trial and assistant professor in the department of medicine at McMaster University.
Dr. Kimberley Lewis and Dr. Waleed Alhazzani led the COMIC trial.
Dr. Lewis and senior author Dr. Waleed Alhazzani, associate professor of medicine at McMaster, led the COMIC trial. They are both critical care physician-researchers at St. Joseph’s Healthcare Hamilton and members of St. Joe’s GUIDE Group, which develops evidence-based clinical practice guidelines.
Findings of the COMIC trial were published in the Annals of the American Thoracic Society.
Prior to the pilot study, Lewis and Alhazzani conducted an international survey of 1197 intensivists from 17 countries. They found that 59 per cent of intensivists do not order a cuff leak test prior to extubation, while the remainder do.
“Based on our survey, there is no clear preference among intensivists on whether or not to use the cuff leak test,” said Lewis. “We aim to address this knowledge gap through a full-scale clinical trial.”
With the illuminating survey results and the success of the COMIC trial, Lewis and her team are working to launch COSMIC, an international, pragmatic clinical trial. COSMIC will assess whether using the cuff leak test to guide extubation management positively affects patient outcomes by avoiding complications like extubation failure or reintubation, which often lead to worse outcomes. The COSMIC trial is set to begin international recruitment in the spring.
“If we can show that the cuff leak test improves patient outcomes, it would have a significant impact on clinical practice guidelines around the globe,” added Lewis.
The COMIC pilot study was supported by the Dr. Paul O’Byrne Research Grant, with methods support from St. Joe’s GUIDE Group.
COMIC co-authors from St. Joe’s include Sarah Culgin, Roman Jaeschke, Dan Perri, Corry Marchildon, Kelly Hassall, and Lehana Thabane.