Respiratory System and Ventilation

• Week Four Objectives focus on gas exchange, perfusion, and pertinent nursing interventions.

Gas Exchange Complications

• Hypoxemia: Reduced blood oxygen due to ventilation/perfusion mismatch or shunting.
• Hypoxia: Inadequate oxygen to tissues, potentially causing organ damage.
• Respiratory Acidosis: Elevated blood carbon dioxide, lowering blood pH.
• Pulmonary Hypertension: Elevated blood pressure in lung arteries due to low oxygen.
• Right-Sided Heart Failure: Right ventricle works harder against high pulmonary pressures.
• Polycythemia: Body compensates for chronic hypoxia by producing more red blood cells.
• Cognitive Impairment: Lack of oxygen impacts mental status and decision-making.

Respiratory System Function

• Ventilation: Air movement into/out of lungs via inhalation/exhalation.
• External Respiration: Oxygen diffusion from inhaled air to bloodstream, carbon dioxide from blood to alveoli.
• Internal Respiration: Oxygenated blood delivery to tissues, carbon dioxide removal to venous blood.
• Additional functions: Air filtration, humidification, vocalization, acid-base balance.
• Adequate gas exchange is crucial for cells to receive oxygen and remove waste.

Lung and Thorax Assessment

• Inspection: Observe rate, rhythm, depth, and symmetry of chest movements; note abnormalities like barrel chest or accessory muscle use.
• Palpation: Assess for tactile fremitus, chest expansion, and tenderness.
• Percussion: Detect dullness (fluid/consolidation) or hyper-resonance (air trapping).
• Auscultation: Listen for crackles, wheezing, or diminished breath sounds.
• Crackles may indicate fluid in alveoli (pneumonia, heart failure).
• Wheezes may indicate airway obstruction (asthma, COPD).
• Diminished sounds may indicate pleural effusion, pneumothorax, or airway obstruction.
• Dullness may indicate fluid accumulation or consolidation.
• Hyperresonance may indicate air trapping from obstructive lung diseases.

Gas Exchange Location

• Gas exchange occurs in alveoli, tiny air sacs surrounded by capillaries near terminal bronchioles.

Factors Affecting Gas Exchange and Lung Compliance

• Reduced alveolar surface area hinders gas exchange (e.g., emphysema).
• Increased alveolar-capillary membrane thickness impairs diffusion.
• Ventilation/perfusion mismatch results from pulmonary embolism.
• Shunting is when deoxygenated blood bypasses ventilated alveoli.
• Surfactant deficiency increases surface tension, reducing lung compliance.
• Decreased lung tissue elasticity (fibrosis or edema) reduces compliance.
• Chest wall abnormalities (kyphosis, obesity) restrict expansion, reducing compliance.
• Increased airway resistance (mucus, bronchospasm) reduces compliance.
• Lung volume issues (over-inflation/atelectasis) reduce compliance.

Factors Affecting Oxygenation

• Ventilation rate and depth.
• Diffusion capacity across alveolar-capillary membrane.
• Ventilation/perfusion mismatch.
• Shunting of deoxygenated blood.
• Inspired oxygen concentration.
• Hemoglobin levels and oxygen-carrying capacity.

Early vs. Late Hypoxia Signs

• Early signs: Restlessness, apprehension, inability to concentrate, dizziness, increased respiratory rate.
• Late signs: Confusion, impaired cognition, cyanosis, bradycardia, hypotension, dysrhythmias, decreased consciousness.
• Recognizing early hypoxia is crucial to prevent organ damage.

Breathing Patterns and Lung Sounds

• Crackles (Rales): Discontinuous sounds from air passing through fluid.
• Wheezes: Musical, continuous sounds from airway narrowing.
• Stridor: High-pitched wheeze from upper airway obstruction.
• Pleural Friction Rub: Grating sound from inflamed pleural surfaces.

Respiratory Changes with Aging

• Decreased respiratory muscle strength and chest wall compliance.
• Increased anteroposterior chest diameter and dorsal kyphosis.
• Decreased lung elasticity and surface area.
• Decreased cough reflex effectiveness.
• Stiffening of chest wall.
• Increased susceptibility to respiratory infections like pneumonia.

Oxygen Therapy

• Administer oxygen using appropriate delivery system and flow rate per patient needs.
• Nasal cannulas deliver 24-44% oxygen for mild/moderate hypoxia.
• Masks (simple or non-rebreather) deliver higher concentrations.
• Venturi masks allow precise oxygen concentration delivery.
• Monitor oxygen saturation, assess for hypo/hyperoxemia, ensure proper fit, provide skin care.
• Safety: Post “Oxygen in Use” signs, address fire hazards, document and monitor frequently.

Nursing Interventions for Respiratory Problems

• Administer oxygen and monitor saturation.
• Use incentive spirometry to improve lung expansion.
• Position patient in semi-Fowler's to optimize breathing.
• Encourage coughing and deep breathing.
• Suction airways if needed for mucus plugs.
• Monitor respiratory rate, effort, and breath sounds.
• Administer bronchodilators or other respiratory medications.
• Educate on energy conservation.
• Promote hydration to thin secretions.
• Provide smoking cessation counseling.
• Goals include improved oxygenation, clear airways, prevent complications, optimize function; early mobility and pulmonary hygiene are essential.

Nursing Interventions for Impaired Gas Exchange

• Administer supplemental oxygen via appropriate delivery system.
• Optimize patient positioning (semi-Fowler's or side-lying).
• Encourage deep breathing exercises.
• Suction the airway as needed.
• Monitor respiratory status.
• Administer prescribed medications.
• Provide emotional support.
• Collaborate with healthcare team for ventilatory support.
• Aim to improve oxygenation, ventilation, clear airways, reduce breathing effort, and prevent complications while treating the cause.

Atelectasis

• It is the collapse of alveoli in the lungs.
• It is caused by airway obstruction, shallow breathing, mucus plugging, or external compression.
• Assessment findings: Diminished breath sounds, crackles, hypoxemia, tachypnea, asymmetric chest expansion detected via X-ray.
• Treatment: Re-expand the affected area through deep breathing exercises, incentive spirometry, chest physiotherapy, suctioning, bronchodilators, bronchoscopy, or surgery.
• Nursing Interventions: Promote lung expansion via positioning, encourage coughing/deep breathing, administer respiratory treatments, monitor status, educate on re-expansion techniques.

Complications of Impaired Perfusion

• Ischemia: Reversible cellular injury from insufficient oxygen.
• Infarction/Necrosis: Irreversible cell death from prolonged ischemia.
• Organ Dysfunction/Failure: Impaired perfusion leading to vital organ failure.
• Systemic Effects: Multi-organ impact leading to cardiovascular collapse.
• Exacerbation: Impaired perfusion worsens underlying condition.

Heart Anatomy and Function

• The heart is a four-chambered pump.
• The right atrium receives deoxygenated blood and sends it to the right ventricle.
• The right ventricle pumps deoxygenated blood to the lungs and transfers it to the left ventricle.
• The left ventricle pumps oxygenated blood to the body.
• Specialized electrical conduction system coordinates atrial and ventricular contractions.
• Heart valves ensure one-way flow.
• Chamber wall thickness relates to pumping force needed against resistance.

Cardiovascular System Assessment

• Inspection: Skin color, edema, pulsations, jugular venous distension.
• Palpation: Apical pulse, peripheral pulses, edema, thrills.
• Percussion: Determining heart borders.
• Auscultation: Heart sounds, murmurs, extra sounds.
• Abnormal Findings: Irregular heart rate/rhythm, murmurs, displaced apical pulse, jugular venous distension, diminished/absent peripheral pulses, edema, cyanosis indicate underlying issues.

Blood Flow and Cardiac Electrical Conduction

• Deoxygenated blood enters right atrium, flows to right ventricle.
• Right ventricle pumps deoxygenated blood to lungs.
• Oxygenated blood returns to left atrium, flows to left ventricle.
• Left ventricle pumps oxygenated blood to body.
• The SA node initiates electrical impulses, travel through atria.
• Impulses reach AV node, travel down Bundle of His/Purkinje fibers. Coordinated electrical activity allows sequential chamber contraction for efficient pumping.

Autonomic Nervous System Effects on Heart Function

• Sympathetic: Increases heart rate, conduction velocity, contractility, enhances cardiac output, prepares for "fight or flight".
• Parasympathetic: Controlled by vagus nerve, decreases heart rate and contractility, conserves energy.

Cardiovascular Disease Risk Factors

• Nonmodifiable: Age, gender (men higher), family history.
• Modifiable: Smoking, dyslipidemia, hypertension, diabetes, obesity, sedentary lifestyle, unhealthy diet, excessive alcohol.

Cardiac Changes with Aging

• Increased stiffness of heart muscle and blood vessels (arteriosclerosis).
• Thickening of heart muscle (left ventricular hypertrophy).
• Slowed electrical conduction.
• Decreased pumping ability (reduced cardiac output).
• Increased risk of arrhythmias like atrial fibrillation.
• Valvular calcification and stiffening.
• Decreased baroreceptor sensitivity influences BP regulation and can lead to hypertension, coronary artery disease, heart failure.

Hypertension (HTN)

• Essential (primary) HTN has no identifiable cause.
• Secondary HTN results from underlying conditions.
• Essential HTN risk factors: Obesity, high sodium, excessive alcohol, sedentary lifestyle, stress, genetics, aging. Secondary HTN causes include kidney disease, endocrine disorders, sleep apnea, medications, and pregnancy complications.

Nursing Interventions for HTN

• Educate on lifestyle modifications (low-sodium diet, exercise, weight management, smoking cessation, stress reduction).
• Emphasize medication adherence, routine blood pressure monitoring, and side effect awareness.
• Encourage patient as active partner in care.
• Stress need for regular follow-ups.

Antihypertensive Medications

• Diuretics (hydrochlorothiazide, furosemide): Promote sodium/water excretion, reduce blood volume, monitor electrolyte imbalances, dehydration, glucose intolerance.
• ACE inhibitors (lisinopril, enalapril): Block angiotensin converting enzyme, dilate vessels, monitor cough, hyperkalemia, acute kidney injury.
• Angiotensin 2 Receptor Blockers (ARBs) (losartan, valsartan): Block angiotensin 2 receptors, similar to ACE inhibitors without cough.
• Calcium Channel Blockers (amlodipine, diltiazem): Relax vascular smooth muscle; risk of edema, flushing, headache.
• Beta Blockers (metoprolol, atenolol): Decrease cardiac output/renin release; monitor bradycardia, bronchospasm, fatigue.
• Alpha Blockers (doxazosin, prazosin): Dilate arteries; risk of orthostatic hypotension.
• Vasodilators (hydralazine, minoxidil): Relax vascular smooth muscle; risk of tachycardia and fluid retention.

Arteriosclerosis vs. Atherosclerosis

• Arteriosclerosis: General hardening/loss of elasticity in arterial walls (normal aging).
• Atherosclerosis: Specific type of arteriosclerosis with plaque buildup in arterial walls, increasing heart disease/stroke risk through inflammation and accumulation of cholesterol, calcium, and debris.

Treatments/Medications for Arteriosclerosis/Atherosclerosis

• Arteriosclerosis: Focus on slowing progression through lifestyle modifications (exercise, smoking cessation, healthy diet).
• Atherosclerosis:
  • Antihypertensives control high blood pressure.
  • Antiplatelet drugs (aspirin, clopidogrel) prevent clot formation.
  • Fibrates (fenofibrate) and niacin improve HDL/triglyceride levels.
  • PCSK9 inhibitors (evolocumab/alirocumab) lower LDL cholesterol.

Patient Education

• Educate on decreasing cardiac risk factors: Smoking cessation, diet (low saturated fats, trans fats, cholesterol, sodium), regular exercise, weight maintenance, limit alcohol.
• Discuss stress management (meditation, yoga).
• Reinforce glycemic control for diabetic patients; educate on dangers of uncontrolled hypertension, promote medication adherence.

Localized vs. Central Perfusion

• Localized perfusion: Blood flow/delivery of oxygen to a specific tissue/organ.
• Central perfusion: Overall blood flow from heart to vital organs (brain, kidneys, liver).
• Impaired localized perfusion leads to blockages/constrictions in specific arteries.
• Central perfusion issues impact multiple organs.

Ways to Encourage Medication Compliance

• Simplify regimens, provide clear/simple instructions, use pill boxes, involve family, explore cost-saving options, address beliefs, use motivational interviewing.

Barriers to Compliance

• Lack of understanding, complex regimen, cost, forgetfulness, cultural beliefs, health literacy, side effects, lack of support, cognitive impairment, lack of motivation.

Nurse's Role in Promoting Smoking Cessation

• Use the 5 A's model (Ask, Advise, Assess, Assist, Arrange). Offer support, educate on benefits of quitting, connect patients with cessation resources, advocate for smoke-free policies.

Explore ventilation/perfusion mismatch, respiratory system mechanics, and the effects of emphysema. Understand lung sounds, gas exchange, and interventions for conditions like atelectasis. Learn about internal respiration and the role of the right ventricle in pulmonary hypertension.