Shorter ventilation time at Intensive Care by electrical stimulus? Research on fitness for respiratory muscles

ICU patients who are artificially ventilated do not use their breathing muscles, weakening them. As a result, patients may lie on the ventilator longer and some may have to be ventilated again after the ventilator is cut off. In an international context, the Radboudumc is investigating with other centers whether electrical stimulation of the respiratory muscles helps patients to be resuscitated shorter and less frequently.

Muscles shrink if you don't use them. This applies to muscles of the arms and legs, but to respiratory muscles as well. A patient who has been ventilated in the Intensive Care Unit (ICU) for a while will at some point start breathing on his or her own again. "We then remove the tube from the throat and the patient has to do it again on his or her own," says professor and head of the ICU department Leo Heunks. "But in about 1 in 5 patients it doesn't work. Then we have to put them back to sleep and reinsert a breathing tube again. Of course, we wanted to know why independent breathing fails in these patients. On investigating this, it seemed to be mainly because patients cannot exhale and cough vigorously enough. If so, the lungs slowly fill up with mucus and spit and the patient has to be ventilated again. So weakened respiratory muscles seem to be the problem."

Fitness for respiratory muscles

Breathing in is done with diaphragm muscles and breathing out with the abdominal wall muscles. The question was how to counteract the weakening of the abdominal wall muscles. A device from the U.S. offered perspective: Heunks: "In theory, the breathing muscles of patients being ventilated in the ICU can easily be stimulated electrically. For example, with stickers on the abdomen you can have patients do breathing exercises twice a day for half an hour, seamlessly attuned to everyone's personal breathing rhythm. That way you arrange fitness for the breathing muscles and hope that muscle mass and muscle strength remain intact as much as possible as a result."

Sooner without ventilator?

At an earlier stage, Heunks tested the stimulator on twenty ICU patients in different hospitals in the Netherlands. The device was indeed found to stimulate muscles, and little or no muscle mass was lost. "Encouraging results," says Heunks, "but in the end you want to know whether IC patients can sooner be taken off life support. And whether this respiratory fitness makes them less likely to need a breathing tube for a second time."

International research

Some time ago, the American company received a large grant to investigate these aspects further. Meanwhile, an international study has started in thirty hospitals in the US, France, Australia and the Netherlands. Erasmus MC, Canisius Hospital and Radboudumc are the Dutch hospitals participating in the trial. Heunks coordinates not only the Dutch study, but also all the research taking place outside the U.S. "A total of about three hundred patients are involved, half of whom will receive the actual treatment," says Heunks. "The other half will be connected to the equipment but will not receive effective treatment and thus act as a control group."

Patient and wallet

The procedure is relatively simple and low-risk. Heunks: "If our research shows that the procedure actually works, that is first and foremost wonderful news for the patient. The sooner someone can get out of ICU, the better. And the less often we have to ventilate the better." It’s also economically advantageous, because a stay in a Dutch ICU easily costs around three thousand euros per patient per day. If you can shorten the length of stay of a large group of patients by one day, then you’re talking about huge cost savings.

Scientific proof

The device has been approved by the FDA in America and in Europe it has a CE mark, which allows it to be used in hospitals. "We use it regularly in our ICU," says Heunks, "because it is so obvious that it can work. But at the same time it’s also a major pitfall. Medical treatments must be based on sound and systematic research. We have to prove scientifically that it works. For that, this current research is essential."

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