Wearing a mask in public areas might impede the spread of the infection disease by preventing both the inhalation of infectious droplets and their subsequent exhalation and dissemination. However, there are few studies on the effect of wearing a mask on cardiopulmonary function. Different types of masks have different effects on increasing expiratory resistance and inspiratory resistance.
During a respiratory disease pandemic, people may need to wear masks for extended period of time to perform daily activities. Cardiopulmonary exercise testing is a important means of the cardiovascular rehabilitation mask assessment by reflecting variable parameters of the body's cardiopulmonary functioning during exercise with increasing load. We use CPET to evaluate the interference of masks on cardiorespiratory reserve and exercise endurance, which can guide the application of masks during a respiratory infectious disease pandemic.
Xiaoyue Zhao will demonstrate biometry evaluation. Yongchun Jiang and Siqing Wang will demonstrate the CPET test. Weijie Lin will be our subject model for the presentation.
Begin by setting the room temperature to 25 degrees Celsius and preparing the first aid equipment. Ask the subject to sit upright without leaning on the back of the chair with their feet on the ground. Ask them to keep their head at a natural level or slightly tilted upwards, but to avoid bending their head down or bending over.
To perform the forced vital capacity test, ask the subject to breathe calmly for five seconds. Then inhale strongly, and then exhale strongly for six seconds. Finally, ask them to inhale back and keep breathing calmly.
Perform the whole procedure under the guidance of a doctor or a formally trained exercise physiologist. To perform the maximum voluntary ventilation test, ask the subject to breathe calmly four or five times. Then repeat the breath continuously for 12 or 15 seconds at the maximum breathing amplitude and the fastest breathing speed.
Briefly tell the subject about the procedure. Then scrape the body hair at the position of the electrocardiograph electrodes. And use 75%alcohol to remove extra dander and grease.
Place the ECG electrodes and attach them to the 12-lead ECG wires. Fix the ECG machine to the chest using a strap. Choose a mask that fits the size of the subject's face and attach it firmly to the face, making sure that there is no gap between the mask and the face.
Fix the flowmeter on the vent and the K4 device onto the vest. Ask the subject to sit on the seat, step on the pedals and adjust the height of the handlebars to a comfortable position for the subject. Have them grab the handlebar with both hands.
Place a blood pressure cuff on the subject's upper right arm for dynamic blood pressure recording. Then place a finger pulse oxygen on the left index finger for the dynamic recording of blood oxygen. Calculate the subject's exercise resistance parameters and set the progressive resistance plan for the exercise phase.
Click on the start button to activate the cycle ergometer. Ask the subject to keep a static sitting posture for two minutes, then start cycling for two minutes. Ask the subject to continue cycling until they can't maintain the pace.
Then ask them to cool down for three minutes. When finished, have the subject keep the static sitting posture for three minutes for observation of vital signs. Then remove data acquisition equipment, face mask, vest and ECG electrodes.
Use the rating of perceived exertion scale to measure physical activity intensity levels that are apparently related to the heart rate during exercise. Then use BORG'S scale to evaluate the exertion of resistance training. A score of six represents resting activity with no effort, and a score of 20 represents exhaustive exercise.
After a 48-hour washout period, select a mask that fits the size of the subject's face and attach it firmly to the face, ensuring that there is no gap between the mask and the face. The 10 participants recruited in this pilot study had similar baseline characteristics such as age and physical fitness. There were no significant differences in age, height or BMI between the male and female groups.
For the spirometry, the female group showed lower FVC, lowered forced expiratory volume in one second, lower MVV and lowered peak expiratory flow compared with the male group. The results of CPET under different conditions are shown here. For exercise tolerance and cardiac function, both male and female groups showed a significant decrease in anaerobic threshold per kilogram and oxygen pulse during the mask-on condition, but no significant differences in the oxygen uptake related to work rate.
The male group also showed a significant decrease in resting heart rate, and the female group showed a significant decrease in peak oxygen uptake per kilogram during the mask-on condition. For ventilatory function, both male and female groups showed a significant decrease in tidal volume while wearing a mask, but no differences were found in the breathing reserve percentage. Both groups showed a significant decrease in ventilation during the mask-on condition, and no difference was found in total CPET performance.
When performing this protocol, subjects should be encouraged to exercise to their maximum endurance, or until the practitioner ends the exercise due to symptoms, such as asthmatic ECG trends, complete apathy, or second or third degree heart block.
