By: Lec 7 Date:20 /11/2017

Transcription

1 By: Lec 7 Date:20 /11/2017 I include the slide within sheet with bold

2 From the previous lecture slide 29 **The respiratory center is divided into three major groups: dorsal, ventral and potine group which made up of two areas the pneuomtaxic centre and the apneustic centre Regulation of respiration Other factors affecting respiration: 1- voluntary control : for short period of times You can perform hypoventilation or hyperventilation voluntary, these are voluntary movements which can regulate the performance of respiration for a short period 2- irritant receptors: stimulated by many incidents coughing & sneezing when Irritation occurs to the mucus membrane of respiratory system 3- J receptor in alveolar walls lead to edema where the patient has dyspnea These receptors are sensory to the change of inflation so they are mostly involved in stimulation of edema where the patient has dyspnea 4- brain edema causes res. centre depression Brain edema when there is a concussion (may be caused by a trauma on the patient's head )which in turn causes depression of res. centre. And we can treat them by using hypertonic solution to remove excess fluid developed in the brain 5- anesthesia & narcotic overdose depresses res. centre (halothane, morphine, pentobarbital) Anesthesia regulatation of anesthesia during surgery is arranged into 4 stages : Stage 1: patient is still feeling Stage 2: patient is still feeling with strong stimulus, here the surgeon can not work Stage 3 : comatose patient, surgeon can work Stage 4: we lose the patient, the patient is die (overdose of anesthesia) Slide 30 Periodic Chyne-Stokes breathing : person over-breathes [O2], [CO2] after seconds these [ ] are sensed by the resp. centre inhibition of excess ventilation opposite cycle begins [O2], [CO2] after seconds these [ ] are sensed by the resp. centre the person is again over-breathing Periodic or chyne stokes breathing is a sort of breathing in which that increase in breathing and then decreased or stopped. Increase in breathing when there is a reduction of blood flow to the brain or reduction of O2 to the brain, then there is a hyperventilation Wash out of the co2 then the respiration will be decreased. Then co2 will accumulate more, increased the hyperventilation. This mainly developed in severe heart failure in which the ejection fraction is will be reduced, so the BF to the brain significantly reduced so oxygen will be reduced and co2 will be accumulated. When the co2 accumulate, it will stimulate the respiratory center. So it will increase the breathing. Washing Co2 then the breathing will be reduced. So this is the periodic or chyne stokes breathing in which the breathing increased or decreased and this is mainly not developed in normal people, but it mainly develops in patients with severe heart failure. And it is related to level of oxygen and carbon dioxide. Slide 31

3 Slide 32 Periodic Chyne-Stokes breathing : this cycle doesn t occur normally but can be seen in these conditions: 1- increased neg. feedback gain in resp. control areas change in [CO2], [H+] causes further great change in ventilation brain-damage 2- long delay in transporting blood from the lungs to the brain severe or chronic heart failure, Slide 33 Sleep apnea: episodes of apnea lasting for 10 secs. Or more, occurring times/night Obstructive sleep apnea: during sleep the pharynx is relaxed, in some individuals this may lead to complete closure snoring & labored breathing apnea O2, CO2 stimulation of resp. center sudden snorts and gasps Sleep apnea: it means cessation of breathing develops frequently during night. Most of us develop apnea during sleeping and this is developed frequently by relaxing of the glottis and then the airway will be closed so the subject will be snoring (شخير) and develops a difficulty in breathing and suddenly he wake up for few seconds and then start breathing again. Slide 34 Sleep apnea usually develops in 1- elderly, obese, nasal ostruction, large tongue, enlarged tonsils Elderly people, obese, and people with enlarged adenoid tissue or the tonsils. And mainly these patients do not sleep quite enough and they will be tired in the next day particularly if they are drivers which in turn increase the risk of accidents. 2- Sudden infant death syndrome (SIDS): exaggerated case of sleep apnea, premature baby, smoker pregnant mother Also In sudden infant death syndrome there is an exaggerated case of sleep apnea develops in premature baby and smoker pregnant mothers.most premature babies do not have enough surfactant. Slide 35 Treatment of obstructive sleep apnea 1- Surgery uvulopalatopharyngoplasty (remove excess fat at back of throat, tonsils, tracheostomy) Surgery to remove excess adipose tissue at back of throat, tonsils or tracheostomy which is an operative procedure that creates a surgical airway. It is most often performed in patients who have had difficulty weaning off a ventilator or positive breathing by special equipment during sleeping. 2- Continous positive airway pressure CPAP Or by CPAP which applies mild air pressure on a continuous basis to keep the airways continuously open in people who are able to breathe spontaneously on their own.

4 Now let s start with pathophysiology Pathophysiology: means the functional the RS when there are some types of disease Slide 2 Reduction of Pulmonary Function 1. Inadequate blood flow to the lungs hypoperfusion 2. Inadequate air flow to the alveoli - hypoventilation Before we continue you have to know that there is 3 main symptoms for pulmonary disease 1- Cough 2- dyspnea 3- chest pain Slide 3-5 Signs and Symptoms of Pulmonary Disease Dyspnea subjective sensation of uncomfortable breathing, feeling short of breath Ranges from mild discomfort after exertion to extreme difficulty breathing at rest. Usually caused by diffuse and extensive rather than focal pulmonary disease. Due to: Airway obstruction Greater force needed to provide adequate ventilation Wheezing sound due to air being forced through airways narrowed due to constriction or fluid accumulation Decreased compliance of lung tissue Signs of dyspnea: Flaring nostrils Use of accessory muscles in breathing Retraction (pulling back) of intercostal spaces Dyspnea: related to the exertion and its classification depends on when the dyspnea develops: Grade 1 at the level of high exercise Grade 2 at the level of moderate exercise Grade 3 mild exercise Grade 4 minimal exercise And sometimes the patient experience dyspnea when he goes to the bathroom Slide 6-9 The common complaint of patient in respiratory disease is cough Cough Attempt to clear the lower respiratory passages by abrupt and forceful expulsion of air Most common when fluid accumulates in lower airways Cough may result from:

5 Inflammation of lung tissue Increased secretion in response to mucosal irritation Inhalation of irritants Intrinsic source of mucosal disruption such as tumor invasion of bronchial wall Excessive blood hydrostatic pressure in pulmonary capillaries Pulmonary edema excess fluid passes into airways When cough can raise fluid into pharynx, the cough is described as a productive cough, and the fluid is sputum. Production of bloody sputum is called hemoptysis Usually involves only a small amount of blood loss Not threatening, but can indicate a serious pulmonary disease Tuberculosis, lung abscess, cancer, pulmonary infarction. If sputum is purulent, and infection of lung or airway is indicated. Cough that does not produce sputum is called a dry, nonproductive or hacking cough. Acute cough is one that resolves in 2-3 weeks from onset of illness or treatment of underlying condition. Us. caused by URT infections, allergic rhinitis, acute bronchitis, pneumonia, congestive heart failure, pulmonary embolus, or aspiration. Cough (commonest) ; which can be from URT or LRT ; depends on the time ( is it at early morning?, is it late night? ), is it productive or dry?, is there a blood in the sputum or not!.. So all these give possibilities of cause. In here, we listen to the patient in order to reach the diagnosis. Slide 10 A chronic cough is one that persists for more than 3 weeks. In nonsmokers, almost always due to postnasal drainage syndrome, asthma, or gastroesophageal reflux disease In smokers, chronic bronchitis is the most common cause, although lung cancer should be considered. Chronic cough means that is continuous. Periodic cough means that it develops at night or early morning and so on. (Periodically) The patient who develops cough with little or no sputum at the early morning is mainly a patient of COPD. Slide Cyanosis When blood contains a large amount of unoxygenated hemoglobin, it has a dark red-blue color which gives skin a characteristic bluish appearance. Most cases arise as a result of peripheral vasoconstriction result is reduced blood flow, which allows hemoglobin to give up more of its oxygen to tissues- peripheral cyanosis. Best seen in nail beds

6 Due to cold environment, anxiety, etc. Central cyanosis can be due to : Abnormalities of the respiratory membrane Mismatch between air flow and blood flow Expressed as a ratio of change in ventilation (V) to perfusion (Q) : V/Q ratio Pulmonary thromboembolus - reduced blood flow Airway obstruction reduced ventilation In persons with dark skin can be seen in the whites of the eyes and mucous membranes. The other possible symptoms of the patient : Cyanosis is the bluish of the skin and nails when there is a reduction of oxygenation of the blood ( which is a type of peripheral cyanosis ) or we can see -- on the tongue or mucus membrane - (which is a type of central cyanosis) Pain Originates in pleurae, airways or chest wall Inflammation of the parietal pleura causes sharp or stabbing pain when pleura stretches during inspiration Usually localized to an area of the chest wall, where a pleural friction rub can be heard Laughing or coughing makes pain worse Common with pulmonary infarction due to embolism The res. pain is mostly lateral and is related to respiration whereas the cardiac pain is central. ** So we listen to the patient, see the patient, examine the patient and one of the important signs that we can see clearly is the cyanosis, we can hear the sounds of breathing ( there is a prolonged expiration which results in increased sound ), restriction in inflation or harsh breathing. The patient with pleural effusion has a sort of crackles, congestion of the heart failure, when there is air or fluid in the alveoli, when you take a breath, the air gets in the fluid ( in bubbles ) so you will hear crepitation because of the air get In the fluid. This is a sign of pul. Edema. So this is one is a sign that we can examine it, see it or hear it. ( clinical finding). Tests of Pulmonary Function Slide 15 Chest radiographs are among the most common examinations of the pulmonary system. Chest x-ray Heart size Lung mass Pleural effusion Fibrosis Pneumonia Pneumothorax This will also give us an idea about the, inflation, any consolidation, any cyst... etc

7 Pneumothorax>> is the presence of air in the pleural cavity and this will lead to collapse of the lung or blockage of the lung according to the volume of the air that present in pleural cavity. The treatment simply, is by putting a chest tube in the pleural space and connect the tube with a water, and this will absorb the air, we need the tube for 2 days and we then repeat the chest X-ray to find out the lung badly inflated or no. When there is a normal inflation of the lung we remove the test tube and we make a suture for the cut. Slide 16 CT SCAN Sometimes we do the CT scan االشعة الطبقية) ) to find out how there is a good inflation in the lungs. Slide Spirometry The diagnosis of COPD is confirmed by spirometry, a test that measures breathing. Spirometry measures the forced expiratory volume in one second (FEV 1 ) which is the greatest volume of air that can be breathed out in the first second of a large breath and the forced vital capacity (FVC) which is the greatest volume of air that can be breathed out in a whole large breath. Normally at least 70% of the FVC comes out in the first second (i.e. the FEV 1 /FVC ratio is >70%). In COPD, this ratio is less than normal, (i.e. FEV 1 /FVC ratio is <70%) even after a bronchodilator medication has been given. Spirometry can help to determine the severity of COPD. The FEV 1 (measured post-bronchodilator) is expressed as a percent of a predicted "normal" value based on a person's age, gender, height and weight: We can ask for lung function test / lung volumes. Here, the specific test of investigation for the diagnosis of the pul. disease is FEV1/FVC ratio which is normally more than 70% When the ratio is less, there is an indication that there is obstructive pul. disease and it can be mild, moderate or severe according to the ratio. The more the reduction of FEV1/FVC ratio, the more the severity of the disease. These patients mostly complain dyspnea with severe disease, and here we ask the patient how long you walk? Or how much effort that you can exerted? You can assess the severity of dyspnea of the disease that is of the patient which is in a relation with the degree of the limitation of the effort. Slide 19 The doctor modifies the table as the following: Severity of COPD Mild FEV 1 % predicted 80 Normal: >= 80 Mild: Moderate: Severe: less than 30 Moderate Severe Very severe <30 or Chronic respiratory failure symptoms

8 **In bronchial asthma, we treat patients by bronchodilators. And in severe bronchial asthma, the patients do not respond to bronchodilators, and it is called status asthmatics and here we take the patient and put him on a respirator. Otherwise we lose the patient Slide 20 From the figure we can see the difference between normal and airway obstruction states **from this figure we can see 1) level (maximum inspiration) 2) the expiration prolonged **as we see in the airway obstruction its take more time to expire the air (prolonged),reduction in the maximum inspiration and need more (extra) muscle to expire the air (abdominal muscle) in attempt to expire as much as possible **so the obstruction lung disease cause difficulty in expiration because of obstruction in the airway and the obstruction may be 1) constriction of the bronchioles and bronchi 2) fibrosis of the elastic tissue of the bronchioles because of inflammation, infection or fibrosis and this will lead to reduction of the elasticity of the tissue of the bronchioles so its not easy to distended **90% of the COPD is due to smoke as major risk factor **as COPD develop we can t treat the disease and the treatment aim to alleviate the symptoms (can t cure the patient) as the disease affect the life style of the patient **other causes of COPD are pollutions ether indoor or outdoor like factor that contain aspis and other chemical substance Slide 21 Ventilation/perfusion ratio (or V/Q ratio) : It is defined as: the ratio of the amount of air reaching the alveoli to the amount of blood reaching the alveoli. "V" - ventilation - the air which reaches the alveoli "Q" - perfusion - the blood which reaches the alveoli These two variables constitute the main determinants of the blood oxygen concentration. In fact since V determines the quantity of oxygen mass reaching the alveoli per minute (g/min) and Q expresses the flow of blood in the lungs (l/min), the V/Q ratio refers to a concentration (g/l). Nuclear study Sometimes we do the V/P ratio ; with a special technique we can find out how much ventilation and how much perfusion. And accordingly we can know if there is a problem in ventilation or in perfusion. Slide 22 Pathophysiology A lower V/Q ratio usually seen in chronic bronchitis, asthma and acute pulmonary edema.

9 A high V/Q ratio increases pao2 and decreases paco2. This finding is typically associated with pulmonary embolism (where blood circulation is impaired by an embolus). And this ratio is mainly increased in pul. Embolism جلطة رئوية) ) that means parts of the lungs are completely blocked, no blood supply but there is ventilation. And here we may be lose the patient if the diagnosis was late. So V/p ratio is increased in pulmonary Embolism but not in asthma, emphysema and so on. slide 23 We also can make some diagnosis like: Pulmonary angiography Laryngoscopy >> is for the larynx Bronchoscopy >> is for the bronchioles If we can t reach the diagnosis we can use the bronchoscopy which we use it to find out if there is any tumors or we take a biopsy (small peace used to examination under the microscope to find if there is a fibrosis, infection) *usually we use the microscopy for reach the diagnosis if the other ways and methods don t give valuable information Slide 24 Skin test (TB) Microbiological (Sputum,Pleural fluid,throat swab) Histopathological and cytological Skin test give us an idea about patient If have TB or not This is type of tuberculin we inject it under the skin and we watch it for a day or two >> as a result if the positive it appear as swelling (flam up) and redness Slide 25 Sputum : It is usually in air passages in diseased lungs, bronchi, pneumonia It can be associate with blood (hemoptysis) if a chronic cough is present, possibly from severe cases of tuberculosis. We can examine the sputum: if the patients complain of productive cough (sputum or mucus) we take the sputum for 1)direct microscopic examination 2)or sent for culture (and this mainly done in case of TB infection) Slide 26 ABG Arterial blood gas analysis commonly performed for individuals with suggested or diagnosed pulmonary disease. Provides valuable information about an individual s gas exchange & acid-base status. We perform the ABG to find the oxygenation of the blood and the blood sample is taken from artery not from vein (any blood from any artery)>> and this will give us a good information about oxygenation, function of the lung, saturation and Po2 Slide 27 Inflammation of trachea or bronchi produce a central chest pain that is pronounced after coughing Must be differentiated from cardiac pain High blood pressure in the pulmonary circulation can cause pain during exercise that often mistaken for cardiac pain (angina pectoris)

10 **can detect by bronchoscopy and take biopsy Slide 28 Respiratory Failure The inability of the lungs to adequately oxygenate the blood and to clear it of carbon dioxide. Can be acute: ARDS or pulmonary embolism Direct injury to the lungs, airways or chest wall Indirect due to injury of another body system, such as the brain or spinal cord. Some time with accident If the chest injury in one side then the pneumothorax develop in one side and the patient still breathing from the other side but some time the injury developed in both side and this is an emergency situation because both lung can be collapsed and if we can t reach the hospital within short period we will lose the patient **in some cases the chest wall is injured and become flexible (pliable) >> in this case we take breathing but you can t expire it so this will collapsing (make pressure) on the lung >> this called flial pneumothorax >> in this case the chest wall moving but appleing pressure so the lung can t be inflated >> this is one of the life threatening situation Slide >> as from slides Chronic respiratory failure Due to progressive hypoventilation from airway obstruction or restrictive disease Respiratory failure always presents a serious threat Dysnpea always present, but may be difficult to detect a change in a chronic patient Since nervous tissue it highly oxygen-dependent, see CNS signs and symptoms Memory loss, visual impairment, drowsiness Headache due to increased intracranial pressure due to cerebral vasodilation Obstructive Pulmonary Disease Characterized by airway obstruction that is worse with expiration. More force is required to expire a given volume of air, or emptying of lungs is slowed, or both. The most common obstructive diseases are asthma, chronic bronchitis, and emphysema. Many people have both chronic bronchitis and emphysema, and together these are often called chronic obstructive pulmonary disease COPD COPD Major symptom of obstructive pulmonary disease is dyspnea, and the unifying sign is wheezing. Individuals have increased work of breathing, V/Q mismatching, and a decreased forced expiratory volume. Pathological changes that cause reduced expiratory air flow

11 Does not change markedly over time Slide 34 Does not show major reversibility in response to pharmacological agents Progressive Associated with abnormal inflammatory response of the lungs to noxious particles or gases. Fourth leading cause of death in U.S. Increasing in incidence over the past 30 years Primary cause is cigarette smoking Both active and passive smoking have been implicated Other risks are occupational exposures and air pollution Genetic susceptibilities identified the upper respiratory tract infection mainly mean the infection of the trachea, bronchi and bronchioles but the lower respiratory tract infection mean the infection of the tissue and include (2,3,4,5) from the following points Infection of respiratory system 1-Upper resp tract inf >>we usually called it common cold 2-Pneumonia 3-TB 4-Fungal inf 5-Tumour and carcinoma **the other possibility of the sign and symptoms is plural effusion **plural effusion: the accumulations of the fluid in the plural cavity which may apply force/pressure in the lung depend on the amount of the fluid The plural effusion can develop from 1)local cause when there is an infection on the plural membrane or infection or problem in the lung as case of TB or pneumonia or from 2)systemic disease(systemic cause) as in case of heart failure, renal failure and liver cirrhosis Good luck *-*