Measure pulmonary ventilation function by spirometer

This is an automatically translated article.

The article was professionally consulted by Doctor Phan Dinh Thuy Tien - General Internal Medicine - Department of Examination & Internal Medicine - Vinmec Nha Trang International General Hospital

Measurement of pulmonary ventilation function by spirometry is a noninvasive method of testing lung function. This technique aims to evaluate the respiratory function of the lungs, thereby detecting some disorders or diseases in the lungs, assessing the severity of the disease and the response to drug treatment.

1. Measure pulmonary ventilation function?

Measuring respiratory function with a spirometer is a fairly safe, non-hazardous and low-toxic method for the operator. Patients are prescribed by the doctor to measure respiratory function when necessary. This method does not cause pain for the patient, almost does not cause discomfort or complications. However, the accuracy of the measurement results depends a lot on the cooperation of the patient.
Respiratory function measurement is a commonly used method in the diagnosis and monitoring of respiratory diseases. This technique helps to record parameters related to lung activity, thereby evaluating two syndromes of ventilation disorders: obstructive and restrictive lung.
Pulmonary function measurement provides accurate information about air flow in the bronchi and lungs. Measurement results are expressed in specific numbers and percentages compared to the values ​​of normal people.

2. Procedure for measuring pulmonary ventilation function by spirometer

2.1. Preparation before measurement Patients should tell their doctor if they have chest pain or are taking medications for lung disease (such as bronchodilators ...) or have a history of drug allergies. Do not exercise excessively, do not do heavy exercise 30 minutes before the measurement.

Do not smoke too much, especially within 6 hours before the time of measurement. Patients must not eat too full before measuring: specifically, do not eat full within 2 hours before measuring. The patient should wear loose, comfortable clothing when taking the measurement. Do not drink alcohol 4 hours before the measurement. In case of using spirometry to diagnose the disease for the first time: do not use bronchodilators at least 6 hours before measuring if using a short-acting type, 12 hours if using a type of effect prolonged, 24 hours if using oral medication such as theophylline. 2.2. The process of measuring pulmonary ventilation function lasts from 15 to 30 minutes. Patients are measured weight, height, nose clamp with specialized clamps, mouth closed breathing tube, inhale and exhale through the mouth. For accurate results, the patient needs to breathe correctly according to the technician's instructions. The patient's entire breathing process will be measured and recorded with a dedicated meter. Return measurement results after 15 minutes. 2.3. Breathing steps when measuring respiratory function The patient is instructed to do 2 important movements:
Movement 1: inhale and exhale normally, then inhale as deeply as possible, then exhale as hard as possible. Movement 2: inhale and exhale normally, then inhale as hard as you can and blow out as fast, hard, as hard as you can, and keep exhaling until at least 6 seconds. When performing any movement, it must be done continuously, without stopping. Because stopping suddenly or doing it incorrectly will cause erroneous measurement results, leading to incorrect assessment of existing lung function results, making diagnosis and treatment inappropriate.

3. Note when reading the results

For patients who smoke, even a normal measurement does not mean that the patient is not at risk for chronic obstructive pulmonary disease (COPD). If the patient's chronic obstructive pulmonary disease progresses, the FEV1 index (maximum expiratory volume in the first second) will gradually decrease. When FEV1 is below 40% of the normal value, this indicates that the patient's lungs are no longer able to maintain normal function, the amount of oxygen in the blood will decrease. Hypoxia will be detected and assessed through a blood gas test. 3.1. Indications of the technique of measuring lung ventilation function Diagnose respiratory diseases when there are other abnormal symptoms and test results: Subclinical tests: hypoxemia, hypercapnia, chest X-ray abnormal, polycythemia vera. Abnormal symptoms: shortness of breath, wheezing, sitting breathing, difficulty exhaling, prolonged sputum cough, prolonged dry cough, chest deformity. Monitor treatment response, disease progression such as bronchial asthma, chronic obstructive pulmonary disease, restrictive lung disease. Lung disease screening in high-risk subjects: Smokers People working in places with smoke and toxic chemicals. Pre-workout health assessment.

3.2. Contraindication Acute respiratory tract infection Hemoptysis of unknown cause Aneurysm of thoracic aorta, abdominal aorta Recent exacerbation of chronic obstructive pulmonary disease, asthma less than 6 weeks Myocardial infarction Ocular surgery, in Abdominal, lower chest 3 - 6 months Unexplained chest pain Unstable chest pain within 24 hours Progressive pulmonary tuberculosis. Measuring pulmonary ventilation function by spirometer is a fairly safe, non-hazardous and low-toxic method for the operator. In order to obtain an accurate diagnosis, the patient must strictly follow the doctor's instructions.
At Vinmec International General Hospital, the method of measuring respiratory function is used in diagnosing respiratory diseases. This technique is performed by a team of highly qualified and well-trained medical doctors, with the support of modern and advanced equipment; professional medical service quality.

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