Lungs: Anatomy, Physiology and Gas Exchange

• The major purpose of the lungs involves gas exchange and oxygen delivery to the body
• The circulatory, musculoskeletal, and neurological systems maintain the respiratory system

Lungs: Anatomy and Physiology

• Air enters the respiratory cycle through the nostrils
• Air is warmed, humidified, and filtered in the nasal cavity
• The oropharynx has a hollow tube that is 5 inches long & located in the middle of the throat behind the mouth
• The trachea is the windpipe in the lower respiratory tract
• The right and left main bronchi located in the lower respiratory tract warm and moisten air
• Bronchioles are transitional airways that support gas exchange
• Alveoli secrete surfactant to reduce surface tension and keep the alveoli moist
• The lungs control blood pH
• The diaphragm is a dome-shaped muscle

Anatomy of the Lungs

• The lungs are cone-shaped and air-filled
• The Pleura is a serous membrane
• The Parietal Pleura adheres to the thoracic wall and produces a serous fluid known as pleural fluid to lubricate the area
• The Visceral Pleura covers the outer surface of the lungs and also secretes a serous fluid to lubricate the pleural cavity

Anterior and Posterior Lobes

• Anterior lobes include: Right upper lobe, Right middle lobe, Right lower lobe, Left upper lobe & Left lower lobe
• Posterior lobes include: Right upper lobe, Right lower lobe, Left upper lobe & Left lower lobe

Landmarks: Thoracic Cage

• Landmarks helps to reference assessment findings and include the anterior and posterior thorax

Diagnostics for Respiratory System

• Pulse oximeter measures the functional oxygen saturation level, or the percent of arterial hemoglobin saturated with oxygen, typically 95 to 100 percent
• Arterial blood gases measure the levels of oxygen and carbon dioxide in the blood, typically drawn from artery sites like the radial, brachial, or femoral artery
• Thoracentesis is the insertion of a needle into the thoracic cavity and is performed for analysis or removal of fluid from the pleural space
• Bronchoscopy is a diagnostic procedure that provides direct visualization of the larynx, trachea, and the bronchial tree.
• Lung biopsy removes a small piece of lung tissue for analysis
• Mantoux tuberculin skin test is a standard method of determining whether a person is infected with mycobacterium tuberculosis

Health History: Respiratory

• Pulmonary disease relates to past medical history, including asthma, COPD, or cystic fibrosis
• Asthma is a reversible reactive airway disease causing inflammation, bronchoconstriction, increased mucus production, and narrowing of the bronchi. Asthma symptoms include cough, congestion, shortness of breath, and wheezing
• COPD is an obstructive and progressive lung disease causing inflammation and destruction of the lung tissue where oxygen is exchanged; COPD symptoms include shortness of breath and congestion
• Cystic fibrosis is a hereditary disease of the exocrine glands which causes the body to produces abnormally thick and sticky mucus that obstructs the lungs and digestive organs
• Bronchitis is a viral or bacterial infection that causes inflammation of the bronchi Common bronchitis symptoms are fever, cough, and lung congestion
• Acute or chronic respiratory infections:
• Pneumonia is a viral, bacterial or fungal infection of the lung which causes inflammation and congestion in the alveoli of the lung; symptoms include fever, cough, congestion, and shortness of breath
• Medications, psychosocial factors, occupation, exposure to environmental pollutants, smoking history, second-hand smoke exposure effect health promotion
• Pneumovax vaccination
• Breathing issues also relate to health hx, including shortness of breath, dyspnea, orthopnea & paroxysmal nocturnal dyspnea
• Cough, whether acute or chronic can be important to health hx
• Chest Pain
• Pleuritic chest pain
• The pack-year is a measurement of the amount a person has smoked over a long period of time
• Pack-years are calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked

Respiratory Assessment Preparation

• Sequence of Assessment is IPPA, or Inspection, Palpation, Percussion, & Auscultation
• Start the patient in a sitting position
• Completely inspect, palpate, percuss, and auscultate the anterior thorax or posterior thorax before moving to the assessment of the other.
• The lateral lobes may be assessed during the anterior or posterior

Thoracic Cage

• Anterior reference lines: Right midclavicular line, Midsternal line & Left midclavicular line
• Posterior reference lines: Right scapular line, Vertebral line & Left scapular line
• Lateral reference lines: Anterior axillary line, Midaxillary line & Posterior axillary line

Assessment

• Examine the size and shape of the thoracic cage
• Inspect anterior, posterior, and lateral cage
• Note the size, shape, symmetry, color & respiratory rate and rhythm

Normal Findings

• The AP-transverse ratio is approximately 1:2
• Conical shape
• Symmetrical
• Skin color uniform
• Respiratory rate 12 to 20 breaths per minute

Abnormal Findings

• AP-transverse ration is approximately 1:1, or barrel chest
• Pectus excavatum – (funnel chest) is a congenital deformity where the sternum is abnormally depressed
• Pectus carinatum – (pigeon breast) is a chest deformity where the sternum protrudes out from the chest
• Muscle retractions indicate problems with air movement. A pro-longed inspiratory phase may indicate upper airway obstruction whereas a prolonged expiratory phase may indicate lower airway obstruction
• Abnormal respirations, skin color, and clubbing of nail plates occur with lack of oxygen or hypoxia; tips of the fingers and nails change in shape and size
• Pursed lip breathing involves breathing through the nose and exhaling through pursed lips; lips look like the patient is whistling. Pursed lip breathing is commonly seen in patients with chronic obstructive pulmonary disease to reduce the work of breathing

Palpating the Thorax

• Assess surface characteristics or tenderness of the thoracic cage
• Gently palpate and assess moisture, surface characteristics and tenderness using your fingertips
• Assess temperature using the dorsal surface of your hand
• Normal findings include dry skin, smooth and uniform surface & warm skin without tenderness
• Abnormal findings include excessive moisture (sweating), irregular surface (lumps or masses), cool or clammy temperature, tenderness & Crepitus, a light crackling or popping feeling under the skin caused by leakage of air into the subcutaneous tissue

Symmetrical Expansion

• Assess symmetrical expansion of the thoracic cage
• Place warmed hands on the posterior chest wall with thumbs at level T (thoracic) 9 or T10, pinch up small fold of skin between your fingers
• Instruct patient to inhale and exhale and observe chest expansion and the expansion of your hands
• Normal findings involve thumbs that move apart symmetrically
• Abnormal findings include asymmetrical expansion which indicates decreased air movement on that side of the lung

Tactile Fremitus

• Purpose: To palpate voice sound vibrations through the bronchi
• Process:
• Instruct the patient to repeat words such as “ninety-nine, coin, toy, or boy” in a low-pitched voice
• Starting just below the clavicle, use palmar base (ball of your fingers) or the ulnar side of your hands and palpate down the anterior lobes as the patient keeps repeating the same word
• Check for voice vibrations
• Repeat on posterior lobes and lateral lobes
• Normal findings include vibrations felt equally on both sides of the lungs
• Abnormal findings occur if palpable vibrations are not felt equally, or if there is increased fremitus that may be related to increased density of the lung tissue or decreased fremitus, that may be related to fluid in the lungs

Percussing the Thorax

• Assess presence of air in each lung and the density of underlying lung tissue
• Use indirect percussion technique and percuss the intercostal spaces moving from the apex to the base on each side of the anterior lung fields
• Percuss each side of the posterior lung fields from the apex to the base, noting the tones of the percussion sounds
• Normal findings include resonance, a low-pitched hollow sound
• Abnormal findings include: Dullness, soft or muffled sounds & Hyperresonance, a low-pitched, drumlike, accentuated percussion sound heard over the lungs when the bronchi and alveoli are hyperinflated with air as in emphysema or asthma

Auscultating the Lungs

• It is important to assess airflow throughout all lobes of the lungs
• Equipment needed is a Stethoscope
• Instruct the patient to inhale and exhale through the mouth
• Auscultate the anterior, posterior, and lateral lung fields from the apex to the base
• Never auscultate over bone
• Bronchial sounds are heard over the trachea and larger bronchi; expiratory sounds are louder and last longer than inspiratory sounds and have a pause between them
• Bronchovesicular sounds are heard over the right and left bronchi; anteriorly over the mid-chest and between the scapula posteriorly
• Vesicular sounds are heard throughout the periphery of the lungs; inspiration sound is longer and louder than expiration
• Abnormal findings include adventitious sounds, diminished breath sounds, crackles, wheezes, rhonchi, pleural friction rub & stridor

Auscultating Advanced Techniques

Bronchophony

• Assess airflow through lungs using a Stethoscope
• Instruct:
• Ask the patient sit on the side of the exam table and lean slightly forward
• Have the patient repeat one of the words "ninety-nine, coin, toy, or boy"
• Auscultate the posterior lung fields moving from the apex to the base on each side of the posterior lung fields, noting the intensity of sound and distinction of the word.
• Normal findings include words becoming less distinct and muffled as you move to the lower chest
• Abnormal findings include the word being clearly auscultated with an increase in sound and intensity

Egophony

• Assess airflow through lungs using a Stethoscope
• Identify a change in timbre, or pronunciation of sound, from “Ee to A.”
• Have the patient repeat the letter "Ee."
• Auscultate the posterior lung fields moving from the apex to the base on each side of the posterior lung fields, noting the distinct sound and clarity of the letter “Ee.”
• Normal Findings - The letter “Ee” becomes less distinct and muffled.
• Abnormal Findings - The letter "Ee” sound changes to the short letter "aaa" sound in areas of increased lung density.

Whispered Pectoriloquy

• Assess airflow through lungs with Stethoscope
• Instruct the patient to whisper the words “ninety-nine” or “one-two-three."
• Auscultate the posterior lung fields, moving from the apex to the base on each side of the posterior lung fields, noting clarity of the
• Normal findings include words that are indistinct or faint
• Abnormal findings include words that are clear and distinctly if there is increased tissue density

Peak Expiratory Flow Rate

• Goal is an assessment of lung functioning and forced expiratory volume of air in the lungs
• For the procedure:
• A Peak flow meter is needed. This meaures peak expiratory flow rate (PEFR) and correlates with how air flows out from the lungs with forcefully
• Instruct sitting or standing patient to take in a deep breath
• Place the peak flow meter in the mouth, with the tongue under the mouthpiece
• Have the patient close the lips tightly around the mouthpiece and blow out as hard and fast as possible
• Instruct to take a few normal deep breaths and repeat the process two more times
• Record the highest number obtained
• Normal findings are in the Green Zone, or 80% to 100% of your highest peak flow
• Abnormal findings include Yellow Zone, or 50% to 80% of your personal best and Red Zone, or less than 50% of your personal best.

Healthy People 2030

• The Goal is to improve respiratory health, which can be encourage by education that involves stopping smoking, addressing environmental pollutants, preventing infection, getting vaccinated & exercising