Leo Heunks appointed as professor of Intensive Care

Leo Heunks has been appointed as professor of Intensive Care at Radboud university medical center / Radboud University. Heunks studies what happens to the respiratory muscles when they remain inactive during mechanical ventilation. Based on this knowledge, he aims to shorten or even prevent ventilation using technical innovations and medication, thus reducing the adverse effects of ventilation.

Mechanical ventilation is a life-saving treatment but may have detrimental effects on the lungs and respiratory muscles, including the diaphragm. Respiratory muscles control breathing, but they remain inactive during ventilation. Just like muscles that become weak when immobilized, as in the case of a broken arm in a cast, these muscles also become weaker. This makes it difficult for patients to wean off ventilation.

Research shows that prolonged ventilation leads to more complications, a higher risk of mortality, and long-term health issues. Therefore, pulmonologist-intensivist Leo Heunks is investigating how to shorten or sometimes prevent ventilation: ‘This not only benefits the patient but also reduces healthcare costs and eases the burden on the limited number of healthcare workers in the ICU.’

Hibernation

Initially, he worked with Coen Ottenheijm from Amsterdam UMC to understand what exactly happens in the respiratory muscles when they are inactive. This research group is the only one in the world capable of taking a biopsy of the diaphragm from a patient in the ICU undergoing surgery. Analysis of this tissue revealed that the mass of the respiratory muscles decreases during ventilation, much like muscles in an arm in a cast, resulting in muscle weakening.

However, that's not the whole story. ‘In those biopsies, we also observed damage caused by the respiratory muscles working too hard’, Heunks explains. ‘This can occur just before the patient ends up in the ICU or when the patient starts breathing independently. Excessive muscle effort leads to muscle damage, similar to what you experience in your arm or leg muscles when lifting heavy loads or running. Additionally, it was discovered that the diaphragm can enter a sort hibernation state. We were already familiar with this concept in the heart muscle, which sometimes protects itself during a heart attack and oxygen deficiency in hibernation state. It appears that the diaphragm can do the same.’

Nasal Cannula

Armed with this knowledge of what happens in the respiratory muscles, Heunks is exploring smart ways to improve ventilation in the clinic. As the lead investigator of an international study, he is examining whether electrical stimulation of the respiratory muscles during ventilation a few times a day is feasible. He is also studying whether a drug that strengthens the heart muscle, levosimendan, can be effective for the respiratory muscles. Heunks: ‘In both projects, I want to determine if we can prevent respiratory muscle weakening and help patients wean off ventilation more quickly.’

Furthermore, Heunks investigating ways to prevent ventilation altogether. ‘Hemodialysis is well-known for removing waste products from the body, and the same principle can be applied to the lungs’, Heunks says. ‘With lung dialysis, a machine removes CO2 from the blood and adds oxygen if necessary. We want to investigate whether this approach can prevent artificial ventilation in selected patients. Additionally, we are examining two other treatments: a nasal cannula that delivers a high flow of oxygen or air, and a tight-fitting mask that provides a small extra volume of air with each breath. These treatments could be valuable alternatives to traditional ventilation.’

Career

Leo Heunks studied Medicine at Radboud University and earned his doctorate in the Department of Pulmonology at Radboudumc with a thesis titled: Exercise-induced oxidative stress in COPD: An experimental and clinical study on the effects of training. In 2000, he began his training as a pulmonologist at Radboudumc. He completed fellowships at Mayo Clinics in Rochester, Loyola in Chicago, and St. Michaels in Toronto. He then worked as a pulmonologist-intensivist and researcher at Radboudumc, Amsterdam UMC, and Erasmus MC. He previously held professorships in Amsterdam and Rotterdam.

Heunks is a fellow of the European Respiratory Society and a member of the scientific committee of the ESICM. Additionally, he serves as an associate editor of the American Journal of Respiratory and Critical Care Medicine. His appointment in Nijmegen is effective from September 1, 2023, for a five-year period.

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