When someone is in respiratory failure, a ventilator takes over breathing to keep oxygen levels stable. However, this support can sometimes harm the lungs, diaphragm, brain, and circulation. New research from UHN shows that both too little and too much breathing effort while on a ventilator can be harmful for critically ill patients.
For patients on a ventilator, if the ventilator does most of the work, the diaphragm can weaken, and parts of the lung may collapse. The brain also becomes inflamed, leading to delirium and cognitive impairment. At the same time, excessive breathing drive—the body’s natural signal from the brain to breathe—results in high breathing effort which can injure the lungs and diaphragm, strain the heart, increase oxygen use, and cause distress. Keeping breathing drive and effort at a moderate level may help prevent these problems, especially in patients with severe lung injury.
However, current ventilator guidelines do not address breathing drive or effort, and their clinical impact on recovery has been unclear. To address this, researchers analyzed data from 1,186 adults who received mechanical ventilation at Toronto General Hospital’s intensive care unit (ICU) between June 2019 and April 2022. Daily measurements of breathing drive and effort were collected for up to 10 days, along with indicators of lung stress and oxygen levels.
The study found that both insufficient and excessive breathing drive and effort were linked to worse outcomes, including a higher risk of death and lower rates of leaving the ICU. Patients with low blood oxygen levels were particularly vulnerable to these effects. Overall, the findings suggest that how much a patient breathes on their own while on a ventilator can affect recovery.
This is the first study to report on the link between breathing drive, breathing effort, and patient outcomes. Monitoring these factors during ventilation could help detect risk early. Personalized ventilator support and other treatments to optimize breathing effort could significantly improve survival and recovery for these patients.
Dr. Jose Dianti, former postdoctoral researcher at the University of Toronto and current Physician at CEMCIC, Buenos Aires, is the first author of the study.
Dr. Ewan Goligher, Senior Scientist at UHN and Associate Professor in the Departments of Medicine and Physiology, is the senior and corresponding author of the study.
This work was supported by the National Sanitarium Association and UHN Foundation.
Dianti J, Lovblom LE, Iftikhar MA, Sahetya S, Telias I, Urner M, Del Sorbo L, Amato MBP, Slutsky AS, Brochard L, Ferguson ND, Fan E, Goligher EC. Association of respiratory drive and effort with mortality and time to discharge in patients on mechanical ventilation in Canada: a longitudinal, prospective, registry-based cohort study. Lancet Respir Med. 2025 Sep 19:S2213-2600(25)00297-8. doi: 10.1016/S2213-2600(25)00297-8. Epub ahead of print.