Examination of the Chest

What is pleural effusion? What does the fluid usually do? What if its just a small amount of fluid?

Accumulation of fluid in pleural space - moves toward gravity dependent eventually and COMPRESSES THE LOWER LUNG REGION, and can compromise aeration. Small collections often asymptomatic, not a huge problem.

Describe another non thoracic exam finding.

Periosteal inflammation (Periostiitis) located in distal shaft of long bones causes limb pain and soft tissue swelling. Common in radius/ulna. Distal tibia/fibula are second most common. Swelling of joints adjacent to distal long bones accompanies periostitis

What is Egophony? What if cough and fever comes with it?

"Goat Sound" - spoken word heard through stethoscope has intensified nasal or bleating quality. Present when examiner hears a long "a" sound over periphery of lung when patient speaks a long "e". Represents increased transmission due to consolidated lung. HIGHLY SENSITIVE for consolidation. If also cough and fever - ego phony also argues for presence of pneumonia.

When right hemi diaphragm percusses more than a few centimeters higher than left hemi diaphragm, what is the Ddx?

actual R diaphragmatic paralysis or R sided lower lung consolidation R sided pleural effusion Massive hepatomegaly

What is kyphoscoliosis? Common causes for it?

Abnormality of the spine in the coronal and saggital plane. (Kyphosis and Scoliosis) that can restrict air movement due to impaired chest wall mechanics. Actually a NON pulmonary cause for RESTRICTIVE disease. Common causes for kyphoscoliosis: dystrophy, cerebral palsy, vitamin D deficient rickets, osteomalacia, connective tissue disease like Marfan syndrome and Elhers Danlos syndrome.

What if you are hearing bronchovesicular and bronchial breath sounds over periphery of lung? What pathologies does this indicate? What pathology might cause just bronchial breath sounds?

Abnormal - Audible that far from large airway indicates increased transmission of expiratory sounds from origin to periphery (alveoli). Bronchovesicular and bronchial breath sounds develop w/ decrease in air/water ratio of pulmonary parenchyma. Helps to transmit from place of origin. Found in many diverse conditions: Alveolar pneumonia, microatelectasis, pulmonary edema, fibrosis, tumor infiltrating parenchyma Extrinsically could be caused by compression of lung from lymph nodes, aortic aneurysm, or enlarged heart. Bronchial may occur over middle of a large pleural effusion, due to compression of underlying alveoli by effusion. However, bottom of a large pleural effusion frequently characterized by silence, caused by compression of underlying alveoli and collapse of airways from weight of collected fluid.

Intensity/Loudness of breath sounds heard w/ stethoscope over chest correlates directly with what? Decreased breath sound intensity over chest is characteristic of what diseases? Decreased breath sounds over chest are characteristic of what diseases?

Amount of ventilation occurring in underlying lung segments Sound intensity decrease: Characteristic of diseases that decrease air flow - chronic obstructive lung diseases, restrictive lung diseases, pneumonia, atelectasis. Decreased breath sounds: characteristics of diseases that block stethoscope from underlying lung parenchyma, like pleural effusion, pleural thickening, pneumothorax, hemothorax, obesity.

Auscultation What area is sound coming from in the: Anterior position Lateral Posterior Where is the point at which you won't hear the upper lobes anymore?

Anterior: Sounds from upper lobes and R middle lobe dominate Lateral: All lobes represented, but R middle lobe heard best here Posterior: Lower lobes dominate. Upper lobes only heard above mid scapula at T3.

What is Kronig's isthmus? What is this supposed to sound like? What does it sound like w/ a problem?

Area over shoulders between neck and shoulder like a tank top straps that represent apex of lung. Is usually hyper resonant - if dullness, strong evidence for consolidation or pleural thickening frequently from TB

What are voice sounds? What increases them?

Auscultatory equivalent of vocal tactile fremitus: During conversational speech, normal air-dense lung transmits low frequency sounds throughout parenchyma while higher frequency are filtered out. Normally spoken voice heard through stethoscope applied to chest wall is indistinct, low pitched mumble. Consolidated lung increases transmission of high and low frequency sounds through stethoscope. Low frequencies increased to point where they are palpable as increased vocal TF. Large pleural effusions (not small) reduce transmission of low but increase transmission of frequencies over 400Hz. This makes voice sounds audible over middle of large pleural effusions, but because low frequency is lower, they are not palpable (decreased tactile fremitus). Note voice sounds diminished by pulmonary hyperinflation.

What is bronchophony? What is whispered pectoriloquy?

Bronchophony describes increase in transmission and clarity of spoken voice as heard thru stethoscope Whispered pectoriloquy describes increase in transmission and clarity of high pitched whispered sounds as heard thru stethoscope - tell patient to whisper sixty six please, compare trachea to lung periphery. If it is same clarity as trachea, patient has WP

Percussion. Using one finger as a hammer and striking the other in contact w chest wall. Waves penetrate 4 to 6 cm deep into chest. Character of note - What does this depend on? Describe: Tympany N1 P1 Hyperresonance N1 P2 Resonance N1 P0* Dullness N1 P3 Flatness N0 P1

Character of note depends on density of tissue through which sound waves pass - water dense is high pitched note, low intensity, air dense is low pitched, high intensity. Five different discernible types: Tympany: Lowest pitch, highest intensity, represents HIGHEST air/fluid ratio. Heard normally over empty stomach (several hours). Heard over a large pneumothorax. Hyperresonance: Low pitched note, moderate intensity. Normal over both lungs at end of full, held inspiration. Bilateral in patients w/ sever emphysema, unilateral in patients with single lobe/segment pneumothorax. Resonance: Low pitched note, moderate intensity. Heard normal in healthy lungs at quiet breathing. Can also be heard in patients w lung disease, so is not always healthy. Dullness: High pitched note, low intensity. Normally heard over solid organ like LIVER with a low air/fluid ratio. Localized dullness heard over areas of consolidation and mild to moderate sized pleural effusions where underlying lung is aerated. In patient with fever and cough, unilateral chest dullness strong sign of pneumonia. Generalized dullness may exist in widespread pulmonary fibrosis. Flatness: Highest pitch, softest intensity. Happens over tissue with lowest air fluid ratio (as bad as thigh muscle). Unilateral flatness over large pleural effusion, which maximally decreases air/fluid ratio by compressing underlying lung parenchyma, causing loss of aeration and atelectasis.

What do the four different sputum colors indicate, when in a cough? What is hemoptysis, its most common cause, and what are the three forms?

Clear/Mucoid - Inhaled irritant Purulent (yellow/green) - infectious bronchitis, pneumonia Putrid - Presence of lung abscess Rusty - Blood presence Hemoptysis - blood in your cough. (most commonly acute bronchitis, causing scant in US) Three types: Scant - blood streaking the sputum Gross - more blood than scant but less than 600 mL Massive - Over 600mL in 24hr

Percussion dullness is also common over what lung change caused by two disorders? How large must a tumor be to be detected by percussion?

Consolidation from pneumonia or atelectasis. Must be over 3cm diameter and less than 5-6cm deep.

Pleural Friction Rub?

Continuous adventitious sound produced when surfaces of visceral and parietal pleura rub together during breathing. Occurs predominantly during expiration and has grating/leathery quality. Inspiratory component may be present. Presence of rub indicates pleural inflammation (pleuritis).

Describe Wheezes.

Continuous, musical adventitious sound caused by vibrations of opposing walls of narrowed airways. Best predictor of airflow obstruction. Absence does not exclude presence of obstruction however. Severe obstruction may prevent too much air for no sounds.

What is Restrictive Lung disease? What is the main cause, and what are four other causes?

Decreased lung compliance causing decreased inspiratory flow. Patients unable to fill lungs with air because lungs are stiff and noncompliant, and lung volumes are typically low. MAIN one: Pulmonary fibrosis Other: Alveolar pneumonia, pulmonary edema, kyphoscoliosis, neuromuscular weakness

What are posturally induced crackles?

Develop only in supine - venous return increase and patients CVP higher, so patients transcapillary pressures higher. If they have high LV, LA, pulmonary vein pressure, then can back up to pulmonary edema when supine. If SEVERE - can hear when upright. Edema will begin in base of lung (higher pressure here). Note if cardiogenic pulmonary edema (can be other causes but beyond scope of course), its transudation of protein poor fluid into pulmonary interstitium and alveolar spaces. Commonly bilateral.

What is something else that can be evaluated w/ percussion? How is this decreased?

Diaphragmatic Excursion - vertical distance of diaphragm movement, which is measured at end of full inspiration and then full expiration. Normal 3-6cm. Decreases in chronic lung disease w/ decreased expiratory flow like emphysema or decreased inspiratory flow like fibrosis. Many patients with either pathology have symmetrically reduced diaphragmatic excursion at around 2-3cm (95% specific for chronic lung disease, but mild disease very frequently normal).

What is Obstructive lung disease? What are 4 examples?

Disease that has increased airway resistance causing decreased expiratory flow. Air trapping in the lung causes hyperinflation: Emphysema, Chronic Bronchitis, Asthma, and Bronchiectasis.

What should crackles be evaluated for?

Pitch. Higher the pitch, more peripheral the disease. Fine crackles - develop when small airways or alveoli that close during expiration POP open during inspiration. Indicated: Alveolar pneumonia, alveolar hemorrhage, alveolar edema. Also - Fibrosis sounds like "velcro being pulled apart" Coarse Crackles - Occurs when air flows through LARGE airways coated in secretions. Turbulent airflow causes small bubbles in secretions to break. This is typical of acute and chronic bronchitis

INSPECTION: First step of the lung exam. First look for Non thoracic exam findings supporting lung disease: Describe one cause.

Fingernail/Toe clubbing - 80% caused by neoplastic/inflammatory lung disease. This can originate from primary/metastatic lung cancer, mediastinal tumors, chronic lung infections 10-15% of other clubbing cases are non pulmonary, 5% are congenital/idiopathic.

What is pectus excavatum? Is this a major clinical issue?

Funnel shaped depression of lower portion of sternum, shifting heart to left. Occurs 1/400 births and progresses at time of rapid bone growth during adolescence Mainly cosmetic, however can prevent complete INSPIRATION and limit exercise in severe cases.

Basic Lung Sounds Where and when do you hear vesicular sounds? What causes the sound? What is an important finding with vesicular sounds? How do the sounds differ in children?

Heard normally over most of chest besides near large airways. Have an inspiratory component that is louder and longer in duration than expiratory. Expiratory probably originate from turbulent airflow in large bronchi and trachea while inspiratory probably from vortices airflow in smaller airways. This is why the inspiratory component will seem louder and longer than expiratory when auscultating over periphery of lung instead of central, larger airways. (note each lobe produces its own vesicular sounds, so vesicular sounds there represent specifically that lobe) Most important when absent over periphery of lung - pathologic processes cause normal vesicular sounds to be replaced by others. In children - same characteristics but higher pitched and louder. Pitch/intensity decrease with age until almost inaudible in elderly.

What is stridor? Two different kinds?

High pitched musical inspiratory sound indicating UPPER airway obstruction. Louder over NECK than chest, in contrast to wheezing. Inspiratory - occurs in tracheal/epiglottic/laryngeal constriction and is an immediate medical emergency. Expiratory - suggest obstruction in bronchus secondary to aspirated foreign body.

Describe a third. Why is this really important to pick up on inspection, in combination with clubbing?

Hypertrophic Osteoarthropathy (HOA) is a combination of periostitis and soft tissue swelling, which is commonly caused by intrathoracic neoplasm (bronchogenic carcinoma, lymphoma, mesothelioma, metastatic cancer). Clubbing/HOA usually develop together and their presence may precede development of underlying malignancy by several years.

Palpation is an important part of the exam, specficially ribs and costochondral junctions, whenever a patient comes in with chest pain. Why? What can you assess by putting hands over both sides of lateral chest? How else can thoracic expansion be quantified more precisely?

If there is tenderness to palpation, CAD probably not occuring, May be costochondritis. Expansion of thoracic cage during breathing. Examiners hands should be over each lateral chest at 8th rib, with thumbs down. Thumbs NORMALLY move 4-6cm symmetrically, but will be severely decreased in patients w/ moderate to severe chronic obstructive lung disease (emphysema more so than chronic bronchitis), Restrictive lung disease (Fibrosis), pneumothorax, major atelectasis of more than one lobe, and in patients with chest wall or spinal deformities. W/ tape measure circumferentially around chest at nipple level, measuring difference between end expiration and end inspiration Expansion measuring less than one inch is abnormal, consistent with emphysema/restrictive lung disease. Over 3 inches is normal.

It is also important to inspect the dynamics of respiration - what does this mean? How does inspiration occur? What will happen during emphysema? When will something other than the diaphragm also be required?

Inspiration should take about same time as expiration in normal patient. Diaphragm is most important muscle for quiet inspiration (moves downward), and external intercostals MAY contribute a little bit to inspiration. In emphysema - lungs are severely overexpanded, and diaphragm is flattened, so it can't descend during inspiration. Normal inspiration will require accessory muscles (scalene, SCM) of respiration and external intercostals. Diaphragmatic paralysis: Inspiratory contraction of external intercostals and accessory muscles necessary to maintain adequate inspiratory airflow when diaphragm becomes paralyzed.

What can increase VTF?

Lung consolidation - air filled alveoli are replaced by serum, pus, or blood, causing higher water density, transmitting sound better than air. Alveolar edema, alveolar pneumonia, alveolar hemorrhage, alveolar fibrosis can increase VTF unilaterally or bilaterally.

How does the abdominal wall move during inspiration and expiration? If this is flip flopped, what abnormality might be present? Is this an emergency?

Moves outward with chest wall during inspiration and retracts inward with chest wall during expiration because downward movement of diaphragm compresses abdominal contents and pushes them outward. More so in men than women. Respiratory/abdominal paradox: Sometimes they may be out of sync - abdominal wall retracts during inspiration Indicates bilateral diaphragmatic weakness/paralysis. Intercostal muscles will be responsible for expanding thoracic cavity during inspiration. These will pull up diaphragm if it is paralyzed. May have respiratory failure and need ventilator. Hypoxemia and CO2 retention will develop from this.

Describe normal expiration. What will emphysema do?

Normal expiration is passive process that depends on elastic recoil. NO MUSCLES required. When forced, requires internal intercostals and abdominal muscles. Emphysema - decreased recoil. Becomes active, requires internal intercostal muscles and abdominal wall muscles. Expiration will be way longer.

What is Vocal Tactile Fremitus? It should be normal anywhere along path from larynx to chest. What does asymmetric VTF mean?

Normal voice producing vibration on chest wall that is palpable. Asymmetric VTF is abnormal, except that VTF over posterior right upper lobe is often greater than VTF over posterior left upper lobe, because trachea closer to apex of right lung than apex of left lung.

Bronchial breath sounds where and when? Why do you hear this sound in this location? What is most unique about this sound?

Normally heard directly over intrathoracic trachea. Have shorter and softer inspiratory component and larger and louder expiratory (inverse of vesicular). Does this because stethoscope located adjacent to origin of expiratory and far from inspiratory origin. This is the only sound with silent gap between two components.

During respiration, what normally happens with the intercostal spaces?

Normally retract slightly during inspiration, bulge outward slightly during expiration. If the inspiratory retraction is exaggerated, may indicate emphysema or pulmonary fibrosis If inspiratory retraction is lost over a given area of chest, there may be underlying consolidation (pneumonia or atelactasis) or pleural effusion.

Pectus Carinatum/Pigeon breast? Is this a big clinical issue?

Occurs when sternum projects beyond frontal plane of abdomen. Occurs in 6/10000 births, may be painful and prevent complete EXPIRATION. May limit exercise tolerance and increase rate of pulmonary infections due to poor ventilation. Bigger clinical issue due to pain, increased rate of pulmonary infections due to poor ventilation, and limiting exercise tolerance

What is flail chest? What causes it?

One or both sides of chest move paradoxically inward during inspiration, and outward during expiration. Develops after multiple rib fractures in one or both sides of chest wall.

What is considered a chronic cough, length wise? Most common causes (3)? Whats a more unusual cause of cough?

Over 3 weeks is chronic. Three most common are SMOKERS -tobacco related bronchitis, ALLERGIES - allergic post nasal drip, and ASTHMA. Some meds can cause side effect (ACE inhibitors, B adrenergic antagonists)

Causes of decreased VTF?

Pleural effusion, pneumothorax, or obesity (fluid, air, or fat accumulating between lung and chest wall). Large airway obstruction (tumor or aspirated foreign body) Small airway obstruction (mucous in acute bronchitis or asthma, or bacteria/inflammatory cells in bronchopneumonia). Pulmonary Hyperinflation (emphysema increasing air density and decreasing water density of lung tissue).

What is unique about pleuritic chest pain? How does it differ from MI? Can it radiate? and what is it most commonly confused with?

Pleuritic pain (can be sharp or dull) increases in intensity with deep breathing/coughing. More localized than visceral pain with MI, however may radiate to ipsilateral shoulder or neck. Can be confused with costochondritis!

What is polyphonic and monophonic wheezing?

Polyphonic - contains several notes starting and stopping at same time like a musical chord. Results from multiple airways obstructed at once. Typica of asthma (mucous plugging), airway edema, or bronchospasm Monophonic - Single note or multiple notes starting and stopping at different times. Monophonic of constant frequency and long duration indicates airway obstruction by intrabronchial tumor or foreign body.

What is d'Espines sign?

Present when sounds over 4th vertebral body bronchial in nature and louder than they are in midline than on both sides of the 4th vertebral body. Normally, vesicular breath sounds are heard on both sides and are decreased in idling. Indicates mediastinal mass.: Lymph node enlargment (can be from lymphoma, sarcoid, metastatic cancer, TB).

What differences will be seen with right and left hemi diaphragm? What will flip this? What can make it seem like this is the case (3)? What is Ewart's sign? What mimics Ewarts sign?

R hemi diaphragm usually percusses 1-2 cm higher than left, but should both move same distance You will percuss left hemidiaphragm higher than right when there is paralysis of left diaphragm Left lower lobe consolidation Percussion dullness from massively enlarged spleen Large PE Ewarts sign - percussion dullness at lower tip of left scapula caused by large pericardial effusion - compresses adjacent lung, causes dullness to percussion possibly obscuring location of left hemidiaphragm by percussion. Mimic - Dullness at tip of scapula can also obscure diaphragmatic dullness when there is marked dilatation of LV seen in chronic aortic regurg (not Ewarts sign)

Mediastinal node enlargement means what?

Usually asymptomatic, often first detected on a routine chest X ray. IF there are symptoms: Cough (irritation of trachea and bronchi) Bronchial obstruction can cause obstructive local emphysema, atelectasis, acute/chronic pneumonia. Hemoptysis secondary to erosion Hoarseness secondary to compression of RLN Dysphagia secondary to esophagus comression SVC syndrome due to obstruction of SVC.

All different types of crackles should be evaluated for what characteristic? What is a post tussive crackle?

Repeatibility. If it clears after 3-4 coughs or after deep breathing, probably of little importance. Just implies small degree of atelectasis and small airway mucous. But crackles that develop in upper lobes after coughing (post tussive) may indicate apical tuberculosis.

What is consolidation? What are its two most common causes?

Replacing alveolar air with solidified lung, often by filling alveoli with fluid or collapsing alveoli. Transmits higher frequency sounds, and decreases the air/fluid ratio of lung tissue. Two common causes: Alveolar pneumonia - inflammatory cells, cellular debris, microbial organisms replace alveolar air LV failure - plasma that leaks from pulmonary capillaries replaces alveolar air.

What is Atelectasis? What two causes are there? What will develop as a result of increased water density of the lung? What about only in Major atelectasis? Will the pleura separate?

Segment of lung collapses because air contained within it when it is reabsorbed into blood stream. Happens when physical obstruction of an airway prevents air from entering alveoli - N2 and O2 contained in here will dissipate into pulmonary circulation, causing alveolar collapse. Can be in MAJOR airways usually caused by a tumor (Major atelectasis) or minor ones caused by mucous (minor atelectasis). Increases water density, produces consolidation. In major atelectasis - there will be dense infiltrates, crowding of ribs, and shifting of affected interlobar fissures. Note that even though there are large areas of alveolar collapse, visceral and parietal pleura do not separate.

Adventitious Lung Sounds: Extra sounds normally absent in respiratory cycle but become superimposed on normal sounds whenever lung disease present. Come in two varieties: Discontinuous or continuous. Most common discontinuous is CRACKLE and most common continuous is WHEEZE. What are crackles (in general)? When is crackling most likely to occur (inspiration or expiration)?

Short, discontinuous, non musical sounds resulting from the opening of small airways due to equalization of pressures between small airways and alveoli of breaking of small bubbles or mucus films located in medium to large conducting airways. Inspiration - During inspiration, airway caliber increases, obstruction resolves. This causes the explosive equalization of pressure, causing crackle.

What is tachypnea? Bradypnea? What does tachypnea indicate, in a hospitalized patient? Bradypnea?

Tachypnea is over 25, bradypnea is under 8. Tachypnea - bad prognostic indicator in hospitalized patients, usually indicates cardiopulmonary disease and could be before arrest. Could also be pneumonia. Bradypnea should prompt eval for presence of hypothyroidism.

Mediasatinal lymph nodes. Explain the two major groups. What can enlargement of the second group mean?

These are inacessible to evaluation on a routine physical exam. Superior group is in front of aortic arch, drains thymus, pericardium, heart, esophagus, trachea. Tracheobronchial group includes pulmonary nodes in hilum of each lung (hillier nodes) along secondary branches of primary bronchi. Enlarged hilar nodes can cause obstruction of respiratory passages. Lateral tracheobronchial nodes run along trace a and intratracheal-bronchial nodes lie at tracheal bifurcation; thiis drains lymph from lungs, bronchi, trachea, heart, esophagus, and liver.

What does dyspnea from chronic lung disease look like? (don't know diseases, just concept) What about acute diseases? How does dyspnea present in most heart and lung diseases? What breathing issues can result from both pulmonary and cardiac disease?

This is caused by emphysema, obstructive bronchitis, pulmonary fibrosis (chronic diseases), and tends to gradually develop, progress slowly. Acute, like PE, pneumothorax, pneumonia, aspiration, pulmonary edema, develop rapidly, progress rapidly as disease worsens. Dyspnea during exertion will occur first, then later on will happen at rest. Orthopnea and PND can happen in both pulmonary and cardiac.

Chest needs to be inspected for shape/symmetry. Abnormalities can be signs of disease. What can cause an abnormal thoracic ratio?

Thoracic ratio is ratio of anteroposterior diameter to lateral diameter of chest. Usually .70-.75, increases with AGE up to .90. Over .90 can occur during emphysema and asthma.

What other two things are important for wheezing? What if you hear wheezing during maximal forced exhalation?

Timing - airway narrower in expiration so wheezing occurs either during expiration alone or during both phases. Inspiratory only indicates severe obstruction. Location - Asthma wheezing usually diffuse, both lungs. Localization to one lung or one lung segment suggests focal airway obstruction (foreign body aspiration). Wheezing during maximal forced exhalation normal in some adults, not reliable for obstruction.

Crackles must be evaluated also for timing. What does a difference here mean?

Timing. Usually inspiratory. Expiratory could mean severe disease. When inspiratory, we subdivide into early and late. Early/mid inspiratory crackles originate in large to medium sized airways, produced by bubbling of air through thin secretions. Argue STRONGLY for chronic airway obstruction in asthma, chronic bronchitis, bronchiectasis, emphysema. Late inspiratory crackles - audible only in latter half of inspiration. Originate in small bronchioles and alveolar ducts and are produced when airways compressed pop open during inspiration. Indicate interstitial edema (heart failure or pneumonia) or fibrosis (interstitial scarring).

Palpation can be used to assess position of what structure? How? What would major atelectasis do? Large pneumothorax? Large pleural effusion? Lung tumor?

Trachea - this is influenced by relative volumes of two sides of thoracic cage and tractive forces on large airways that can pull trachea away from midline. Patient sitting erect - examiner places one index finger in suprasternal notch to feel trachea - normally, should be either in midline or within 4mm to the right. Major atelectasis (involving one or more lobes on one side of chest) decreases volume sufficiently, pulling mediastinum and trachea TOWARD side of atelectasis Large pneumothorax introduces air into pleural space around one lung, collapsing lung, expanding chest wall, pushing trachea AWAY from side of pneumothorax Large pleural effusion increases volume of thoracic cage on side of effusion, trachea pushes AWAY from side w/ effusion Rarely, a lung tumor may surround/entangle a bronchus, pulling bronchus to one side, causing trachea to shift toward side of tumor.

Bronchovesicular breath sounds heard where and when? How does it compare to vesicular?

Transitional sounds - equal duration in inspiration and expiration. Heard best normal near large airways on either side of sternum and in-between scapulas. Duration and intensity enhanced compared to vesicular because stethoscope located nearer source of expiratory sounds.

What is Pneumothorax? What is tension pneumothorax? What might you see as a secondary effect?

When atmospheric air pressure enters pleural space - causing lung to collapse, chest wall to expand outwards, and v/p pleura to separate from each other. Tension - Where intrapleural pressure higher than atmospheric - develops when air is drawn into pleural space during inspiration but can't leave on expiration, and progressively rises with each breath. Ultimately compression of great vessels, heart, and opposite lung that can cause cardiac filling to be so low CO becomes critical