Pulmonary ventilation

Lung ventilation refers to the amount of gas that enters and exits the lungs per unit time. Generally refers to the dynamic volume of the lungs, which reflects the ventilatory function of the lungs. Lung ventilation can be divided into minute ventilation, maximum ventilation, ineffective air volume and alveolar ventilation. The amount of ventilation per minute refers to the amount of air inhaled or exhaled per minute, that is, the product of tidal volume and respiratory rate. Clinically, it is often seen that some patients with shallow breathing may experience insufficient ventilation and hypoxia. In the rescue of patients whose breathing suddenly stops, the patient's thorax is enlarged and reduced by artificial respiration to maintain lung ventilation. But be careful not to use too much force to prevent damage to the ribs, but also to pay attention to the amplitude, so that alveolar ventilation achieves sufficient effect. Basic Information Specialist classification: Respiratory examination classification: pulmonary function test Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Below normal values ​​generally indicate that the body may have lung disease. Normal value: Male: 6463-6863ml Female: 4057-4377ml Above normal: Above normal, it is generally normal. negative: Positive: Tips: Not suitable for the crowd: severe heart and lung disease and hemoptysis, listed as taboo. Normal value Resting ventilation per minute: The normal male is about 6663±200ml, and the female is about 4217±l60ml. Of the tidal volume of calm breathing, about 25% comes from the contraction of the intercostal muscles, and 75% depends on the lifting movement. Therefore, the volume of tidal volume is not only related to gender, age, height, body surface area, but also affected by thoracic and sacral movements. The calculated value is subject to BTPS correction. Maximum ventilation: Normal males are about 104±2.71L and females are about 82.5±2.17L. Usually, they should be judged according to the measured value of the predicted value, and 80% of the predicted value is abnormal. Clinical significance Abnormal results: A VE below 3 liters indicates insufficient ventilation, and a level above 10 liters is hyperventilation. It should be noted that this value is normal and does not mean that the respiratory function is normal. MVV reduction is seen in 1 airway obstruction and lung tissue elasticity, such as obstructive emphysema; 2 respiratory muscle weakness and respiratory insufficiency; 3 thoracic, pleural, diffuse pulmonary interstitial disease and large area of ​​lung parenchymal disease, such as lung Does not stretch, restricting the relaxation and contraction of the lungs. It is necessary to check the evaluation of the lung function status of patients before thoracic surgery and the identification of occupational disease labor ability. Low results may be diseases: asthma, asthma, kidney cough in children Taboo before inspection: Keep quiet for a while. Attention during the examination: standing position, with the doctor. Inspection process 1. The minute ventilation (VE) is the amount of air entering and leaving the lungs per minute at rest, equal to the tidal volume (VT) x respiratory rate (RR) / minute. Preparation and measurement: The spirometer and the pipe are first flushed with air and then filled with air to about 1/2 of the volume. The tone drum paper was quickly adjusted to 30 mm/min. The subject was rested in bed for 15 minutes, and after the breathing was stabilized, the measurement was started by connecting with the spirometer. Repeat breathing for 2 minutes while recording the breathing curve and automatic oxygen consumption. VE was calculated by selecting a smooth breathing curve, a baseline level, and a uniform oxygen uptake curve for 1 minute. 2. Maximum ventilation (maximalvoluntary ventilation) (MVV) is the maximum ventilation rate and the deepest possible breathing amplitude to maximize the amount of ventilation achieved by repeating breathing for one minute. Determination method: There are two kinds of closed type and open type, the latter is suitable for large-scale screening and screening of grassroots. The subject takes the standing position and is connected with the swelling meter. After 4 to 5 times of calm breathing, the breathing is repeated for 12 seconds or 15 seconds with the fastest breathing speed and the maximum breathing amplitude, and the number of breathing requests is 10-15 times. Repeat after 10 minutes of rest. In order to make the measurement successful, it is necessary to fully explain to the subject beforehand, and timely instructions and continuous guidance and encouragement are given to the subject to obtain the best result. Calculation: Select a curve with a uniform breathing rate and a consistent amplitude for 12 or 15 seconds. Multiply the volume of the exhaled or inhaled by 5 or 4 to obtain the maximum ventilation per minute. The difference between the two measured results is required to be <8%, and the maximum value should be selected as the measured value. Not suitable for the crowd Severe cardiopulmonary disease and hemoptysis are not suitable for this test, because forced exhalation will aggravate the condition. Adverse reactions and risks The test is a non-invasive test that does not cause serious complications or other hazards.