Stroke increases the risk of pneumonia in two ways. First, as a result of weakened muscles from bed rest. And secondly, due to the neurological weakness of the chest wall muscles as a direct result of a stroke. Stroke can adversely affect the coughing function as a result of this weakness. Coughing is necessary to clear secretions and to prevent choking or the inhalation of food into the lungs. Taking in deep breaths helps open the small air sacs and keep them from collapsing. Collapsed air sacs (alveoli) lead to fluid collections in the lung. This fluid build-up can cause pneumonia and impaired oxygen uptake and exchange.
Researchers from Korea developed a training program to ease the actions of each respiratory muscle. Two assistive devices helped with forceful exhalation and inhalation. The goals were to improve lung function and protect patients from post-stroke pneumonia.
Design of the study
Forty stroke patients participated in this study. Both the intervention group (20 patients) and control group (20 patients) participated in a conventional stroke rehabilitation program for 30 minutes twice a day, five days a week, over three weeks. The intervention group also took part in bedside respiratory muscle training, 30 minutes, twice a day for seven days a week over a three-week period. Researchers designed the training program to target both the inspiratory (breath-in) and expiratory (breath-out) muscles.
The program consisted of three sessions: 10 minutes of breath stacking exercise, followed by 10 minutes of inspiratory muscle training and 10 minutes of expiratory muscle training.
Breath stacking involves taking in a full breath through the nose while allowing the stomach and lower rib cage to expand outward. Subsequently, the patients drew in a second and third breath until their lungs were full. The patients held their breath for 2 to 3 seconds and then blew the air out through pursed lips.
Inspiratory muscle training involves using a device called a spirometer. This is a see-through device that has three chambers and measures air flow. After the patient breathes out to empty their lungs, the patient places their mouths over the mouthpiece and takes slow maximal inhalations. As the amount of air taken in increases, the ball in the device rises to give visual feedback as to how well the patient is doing. Then, the patient holds his breath for 3 to 5 seconds before exhaling. Spirometry also decreases asymmetric expansion between the right and left rib cages in patients with stroke.
The positive expiratory pressure (PEP) device was selected for muscle training while exhaling. The PEP device and the resistance created during exhalation may also increase the function of expiratory muscles. Patients initially took in a larger-than-normal breath but did not fill the lungs to full capacity. After holding their breaths for 2 to 3 seconds, the patients exhaled actively. However, they were not to breathe forcefully so that the exhalation time was three to four times longer than a typical inhalation time.
Maximal lung inflation is thought to open collapsed alveoli and prevents them from collapsing. Furthermore, it increases lung volume, improves the ability to cough away phlegm and mucus, and reduces the incidence of lung infection.
Results and conclusion
All lung function tests except one (FEV1/FVC) were significantly improved in the intervention group after three weeks of respiratory muscle training. Also, the improvement was independent of the conventional stroke rehabilitation programs. During the investigation, no participant in the intervention group was treated for pneumonia, whereas two participants in the control group were diagnosed with pneumonia. However, this was not considered statistically significant, meaning it could have been due to random chance rather than as a result of the intervention. Researchers need to conduct more extensive studies to show this benefit.
This video from the Nebraska Medical Center explains how to use a spirometer.
These two devices, spirometer, and PEP are inexpensive, easy to use tools. Patients can use them independently after minimal instruction. Since many stroke patients in the hospital are resting in bed, their lung and rib muscles become weak. Patients can use one of these devices daily both in and out of the hospital. These devices are portable and used only for one-person. Therefore, take this device home with you after your hospital stay. Hospital workers will throw it away when you leave. You can continue this therapy at home on your own.
The lead author of this study is Hyun-Joon Yoo, M.D., Department of Physical Medicine and Rehabilitation, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea Brain Convergence Research Center, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.