Introduction to Respiratory System PDF

Approach to the Patient with Disease of the Respiratory System  subject 1-introduction. 2-symptoms 3-Diagnostic procedurs. 4-pulmonary function test. 5-classification of disease  introduction Patients with disease of the respiratory system generally present because of symptoms...

Approach to the Patient with Disease of the Respiratory System  subject 1-introduction. 2-symptoms 3-Diagnostic procedurs. 4-pulmonary function test. 5-classification of disease  introduction Patients with disease of the respiratory system generally present because of symptoms, an abnormality on a chest radiograph, or both.  Respiratory cycle  To maintain normal gas exchange to the tissues, an adequate volume of air must pass through the lungs for provision of O2 to and removal of CO2 from the blood.  A normal person at rest typically breathes approximately 500 mL of air per breath at a frequency of 12 to 16 times per minute, resulting in a ventilation of 6 to 8 L/min (minute ventilatione).  alveolar surface area (typically 70 m2) for blood-gas diffusion within the modest volume of a thoracic cavity (typically 7 L),.  symptoms Dyspnea: Shortness of breath, it is a subjective feeling experienced by the patient. their descriptions tend to fall into three primary categories: (1)air hunger or suffocation. (2) increased effort or work of breathing. (3) chest tightness.  Dyspnea Upper airway obstruction, which is defined here as obstruction above or including the vocal cords, is caused primarily by foreign bodies, tumors, edema (e.g., with anaphylaxis), and stenosis. Acute :over a period of minutes to days. laryngeal edema or acute asthma. Subacute :over days to weeks chronic :(over months to years) chronic obstructive lung disease, chronic bronchiolitis.  symptoms Orthopnea  or shortness of breath on assuming the recumbent position,  often is quantitated by the number of pillows or angle of elevation necessary to relieve or prevent the sensation.  The main causes of orthopnea is an increase in venous return and central intravascular volume on assuming the recumbent position..  symptoms Paroxysmal nocturnal dyspnea( PND): is waking from sleep with dyspnea. As with orthopnea the recumbent position is important, but this symptom differs from orthopnea in that it does not occur soon after lying down. Platypnea : is shortness of breath when the patient is in the upright position.  symptoms Cough : It is a physiologic mechanism for clearing and protecting the airway. may indicate the presence of lung disease, but cough per se is not useful for the differential diagnosis. Acute cough :defined by a duration of less than 3 weeks, is most commonly due to an acute viral infection of the respiratory tract, such as the common cold.. symptoms Sub acute cough :is defined by a duration of 3 to 8weeks chronic cough :lasts 8 or more weeks. Whereas chronic bronchitis is a particularly frequent cause of cough in smokers, common causes of either subacute or chronic cough in nonsmokers are postnasal drip (also called upper airway cough syndrome), gastroesophageal reflux, and asthma. symptoms sputum The presence of sputum accompanying the cough often suggests airway disease and may be seen in patients with asthma, chronic bronchitis, or bronchiectasis. Yellow or green sputum reflects the presence of numerous leukocytes, either neutrophils or eosinophils symptoms Hemoptysis :  can originate from disease of the airways, the pulmonary parenchyma, or the vasculature.  Diseases of the airways(e.g., bronchitis) are the most common causes of hemoptysis. symptoms Chest pain:  caused by diseases of the respiratory system usually originates from involvement of the parietal pleura.  Pain involving the pleura or the diaphragm often is worsened on inspiration; in fact, chest pain that is particularly pronounced on inspiration is described as ―pleuritic.” Diagnostic procedures Chest –Xray:Chest radiographs usually are taken in two standard views—posteroanterior (PA) and lateral. For a PA film, the x-ray beam goes from the back to the front of the patient, and the patient’s anterior chest is adjacent to the film. The lateral view is taken with the patient’s side against the film, and the beam is directed through the patient to the film. CONCILDATION COLLAPSE Fibrosis  Diagnostic procedures COMPUTED TOMOGRAPHY With this technique a narrow beam of x-rays is passed through the patient and sensed by a rotating detector. high-resolution CT, the thickness of individual cross-sectional images is reduced to 1 to 2 mm instead of the traditional 5 to 10 mm Diagnostic procedures Advantage: 1, the use of cross-sectional images allows distinction between densities. 2, CT is distinguishing subtle density differences between adjacent structures, and providing accurate size assessment of lesions. 3,makes it possible to distinguish vascular from nonvascular structures. 4,Helical CT technology results in faster scans with improved contrast enhancement and thinner collimation. The image is obtained during a single breath-holding maneuver that allows less motion artifact. Diagnostic procedures Magnetic Resonance Imaging(MRI): Magnetic resonance provides poorer spatial resolution and less detail of the pulmonary parenchyma. MR is well suited to distinguish vascular from nonvascular structures without the need for contrast. MR can be useful in demonstrating pulmonary emboli, defining aortic lesions such as aneurysms or dissection, or other vascular abnormalities. Diagnostic procedures Positron emission tomographic (PET) scanning is commonly used to identify malignant lesions in the lung, based on their increased uptake and metabolism of glucose. can be detected by a specialized PET camera or by a gamma camera. can differentiate benign from malignant lesions as small as 1 cm. Diagnostic procedures Pulmonary Angiography: The pulmonary arterial system can be visualized by pulmonary angiography, in which radiopaque contrast medium is injected through a catheter placed in the pulmonary artery. Ultrasound US is nonionizing and safe to perform on pregnant patients and children. It is helpful in the detection and localization of pleural abnormalities, and a quick and effective way of guiding percutaneous needle biopsy of peripheral lung, pleural, or chest wall lesions. Diagnostic procedures Virtual Bronchoscopy: Medical Techniques for Obtaining Biologic Specimens -Collection of Sputum. -Percutaneous Needle Aspiration (Transthoracic) -Bronchoscopy PULMONARY FUNCTION TESTS The primary function of the respiratory system is to oxygenate blood and eliminate carbon dioxide, which requires that blood come into virtual contact with fresh air to facilitate diffusion of respiratory gases between blood and gas. This process occurs in the lung alveoli, where blood flowing through alveolar wall capillaries is separated from alveolar gas by an extremely thin membrane of flattened endothelial and epithelial cells, across which respiratory gases diffuse and equilibrate. PULMONARY FUNCTION TESTS 1. Total lung capacity (TLC): Total volume of gas within the lungs after a maximal inspiration 2. Residual volume (RV): Volume of gas remaining within the lungs after a maximal expiration 3. Vital capacity (VC): Volume of gas expired when going from TLC to RV 4. Functional residual capacity (FRC): Volume of gas within the lungs at the restingstate, that is, at the end of expiration during the normal tidal breathing pattern 5-forced vital capacity (FVC):The total amount of air exhaled. 6- forced expiratory volume in one second (FEV1) :the amount of air exhaled in the first second. note that FEV1 is a flow rate, as it reveals volume change per time. As with lung volumes, an individual's maximal expiratory flows should be compared to predicted values based on height, age, and gender. While the FEV1/FVC ratio is typically reduced in airflow obstruction, airflow obstruction can also reduce FVC by raising RV. If this occurs, the FEV1/FVC ratio may be "artifactually normal," Flow volume loop Air way obstraction Central obstruction 5-classification of disease obstructive Asthma Chronic obstructive lung disease Cystic fibrosis Restrictive-parenchymal Sarcoidosis Idiopathic pulmonery fibrosis Pneuoconiosis Restrictive-extraparenchymal Neuromuscular (GBS, Myasthenia gravis) Chest wall Respiratory failure Respiratory failure is a syndrome of inadequate gas exchange due to dysfunction of one or more essential components of the respiratory system: -Chest wall (including - Pulmonary circulation pleura and diaphragm) -Airways. -Alveolar–capillary units. -Nerves. -CNS or Brain Stem.