Oxygenation, Labs & Diagnostics

1. Overview of Oxygenation & Cardiopulmonary System

  • Oxygenation is the process of delivering oxygen to cells, tissues, and organs.

  • Four systems assist with oxygenation:

    • Musculoskeletal (MS) and Neurological (Neuro): Regulate air movement.

    • Pulmonary (Respiratory): Oxygenates blood.

    • Cardiovascular (CV): Circulates oxygenated blood.

2. Cardiovascular System Functions

  • Circulation: Blood flow through the body.

  • Perfusion: Blood flow to capillary beds to nourish tissues.

  • Heart Structure: Four chambers (2 atria, 2 ventricles) with valves.

  • Cardiac Cycle: Atria contract, followed by ventricles, regulated by electrical impulses.

  • Cardiac Output: Heart rate (beats/min) x Stroke volume (L/beat).

  • Blood Vessels: Arteries → Arterioles → Capillaries (exchange gases) → Veins (return to heart).

  • Respiration: Exchange of O₂ and CO₂.

3. Respiratory System Functions

  • Ventilation: Air movement; includes:

    • Inspiration: Diaphragm contracts, air flows in.

    • Expiration: Diaphragm relaxes, air flows out.

  • Respiration: Gas exchange at alveoli level.

  • Controlled by neural and chemical signals.

4. Common Cardiovascular Disorders

  • Coronary Artery Disease (CAD): Narrowed coronary arteries lead to reduced blood flow.

  • Arrhythmias: Irregular heartbeats affecting oxygen delivery.

  • Congestive Heart Failure (CHF): Heart can’t pump effectively; leads to fluid buildup.

  • Peripheral Vascular Disease (PVD): Reduced blood flow to limbs.

5. Respiratory Disorders

  • Chronic Obstructive Pulmonary Disease (COPD): Includes emphysema (loss of elasticity) and chronic bronchitis (inflammation).

  • Asthma: Airway constriction due to irritants.

  • Pneumonia: Lung infection with symptoms like fever and difficulty breathing.

  • Atelectasis: Collapse/blockage of alveoli. Risk factors include anesthesia and bed rest.

6. Hematologic Factors Affecting Oxygenation

  • Anemias: Lowered oxygen-carrying capacity of blood, affecting overall oxygenation.

7. Assessment Techniques

  • Health History: Chief complaints, focused questions on symptoms.

  • Physical Exam:

    • Vital Signs: BP, respiratory rate, pulses.

    • Inspection & Palpation: Chest shape, muscle usage, heart vibrations.

    • Auscultation: Lung sounds for abnormalities; heart sounds.

  • Vascular Assessment: Peripheral pulses, skin color/texture, capillary refill, edema.

8. Laboratory & Diagnostic Tests

  • Pulmonary Function Tests (PFTs): Measure air movement; tracks disease progress.

  • Arterial Blood Gases (ABGs): Assess oxygen and CO₂ levels.

  • Basic Metabolic Panel: Detects electrolyte imbalances which can cause arrhythmia.

9. Management of Impaired Gas Exchange

  • Goals:

    • Stabilize respiratory rate (16-24 breaths/min).

    • Increase SpO₂ above 85%.

    • Improve lung sounds and reduce dyspnea.

10. Promotion of Oxygenation

  • Airway Management: Deep breathing, coughing, incentive spirometry.

  • Oxygen Therapy: Monitor effectiveness, safety measures, document patient tolerance.

  • Suctioning: Clear airways, collect sputum.

  • Oxygen Delivery Systems:

    • Nasal Cannula: Low flow.

    • Masks (Simple, Rebreather, Venturi): Higher flow, specific O₂ delivery.

    • CPAP & BiPAP: For sleep apnea, pneumonia, COPD.

11. Medication Administration

  • Bronchodilators: Open airways.

  • Corticosteroids: Reduce inflammation.

  • Mucolytics: Thin secretions.

12. Additional Therapeutic Measures

  • Hydration: 2800 mL/day recommended, avoid caffeine.

  • Chest Physiotherapy: Postural drainage, deep breathing.

  • Pharyngeal Airways: Prevent airway obstruction.

13. Patient Education & Positioning

  • Educate on lifestyle changes: diet, exercise, and smoking cessation.

  • Importance of vaccinations (influenza, pneumonia).

  • Proper positioning for optimal lung expansion.

14. Nursing Roles in Diagnosis and Care

  • Diagnostic Communication: Relay test results and patient status to the healthcare team.

  • Patient Monitoring: Continuous assessment and adaptation of care plans based on response to treatment.

15. Blood Cell Types and Functions

  • WBCs (Leukocytes): These cells are essential to the body’s immune and inflammatory responses, defending against infections and foreign substances.

  • RBCs (Erythrocytes): These contain hemoglobin, a crucial protein for oxygen transport to tissues and carbon dioxide removal. RBCs contribute to maintaining acid-base balance and are formed in the bone marrow.

  • Platelets (Thrombocytes): Key players in blood clotting; they aggregate at the site of a vessel rupture to form a plug, stopping bleeding. They are also formed in the bone marrow.

  • Plasma: The fluid part of blood, primarily composed of water, carries substances necessary for homeostasis:

    • Electrolytes: Help maintain body functions.

    • Hormones: Regulate physiological processes.

    • Nutrients: Transport essential molecules for cell function.

    • Plasma Proteins:

      • Albumin: Maintains fluid balance by regulating osmotic pressure.

      • Fibrinogen: Important for blood clot formation.

      • Globulins: Involved in immune functions.

16. Pre-procedure Essentials

  • Standard Precautions: Follow infection control practices to ensure safety.

  • Patient Identification and Allergies: Confirm identity and check for allergies, especially to medications and latex.

  • Informed Consent: Ensure that the patient has given consent after understanding the procedure’s purpose and risks.

  • Medication Review: Note any medications the patient is taking that could affect the procedure.

  • Venipuncture: Familiarize yourself with the proper technique, selecting appropriate sites for blood draw.

  • Labeling: Ensure that specimens and containers are accurately labeled to prevent errors.

  • Documentation: Record all relevant information about the procedure and patient response.

17. Blood Tests Overview

  • Venous Blood Sample: Frequently used to measure various blood components and assess overall health.

  • Arterial Blood Sample: Used for arterial blood gas (ABG) analysis to measure oxygen and carbon dioxide levels, pH, and bicarbonate.

  • Capillary Blood Sample: Typically used for quick tests like fingerstick glucose, especially in diabetic patients.

18. Complete Blood Count (CBC)

  • CBC: A common test that measures different components of the blood, giving insights into general health and detecting conditions like anemia or infection.

    • RBC Count: Indicates oxygen-carrying capacity.

    • Hemoglobin: The iron-containing protein essential for oxygen transport.

    • Hematocrit (HCT): Measures the proportion of RBCs in blood, providing information about fluid balance and anemia.

    • WBC Count and Differential: Evaluates immune function, identifying specific types of WBCs (like neutrophils and lymphocytes) which help diagnose infections and immune disorders.

    • RBC Indices (MCV, MCH, MCHC): Provide details about RBC size and hemoglobin content, which can indicate types of anemia.

19. Coagulation Studies

  • Platelets: Assess clotting ability and diagnose conditions like thrombocytopenia, where there is a low platelet count.

  • Prothrombin Time (PT): Measures how long it takes blood to clot, commonly used to monitor warfarin therapy effectiveness.

  • International Normalized Ratio (INR): Standardized PT measurement, important for patients on anticoagulants like warfarin.

  • Partial Thromboplastin Time (PTT): Assesses the intrinsic pathway of coagulation, useful for monitoring heparin therapy and detecting bleeding disorders.

20. Basic Metabolic Panel (BMP)

  • Electrolytes (Sodium, Potassium, Chloride, Bicarbonate): Critical for cellular function, fluid balance, and pH regulation.

  • Carbon Dioxide (CO2): Indicates respiratory and metabolic function.

  • Glucose: An essential energy source, with blood levels often monitored in diabetes management.

  • Renal Function Tests (BUN, Creatinine): Evaluate kidney function by measuring waste products filtered by the kidneys.

  • Hemoglobin A1c: Reflects average blood glucose over 2-3 months. An A1c > 6.5% suggests diabetes, while levels above 7% indicate poor glucose control.

21. Capillary Glucose Testing

  • Purpose: Monitors blood glucose, especially in diabetes, to gauge insulin needs and therapy effectiveness.

  • Instructions for UAP:

    • Test timing (before meals, at bedtime) as ordered.

    • Avoid areas with cuts, bruises, or scars.

    • Use preferred sites, typically the sides of the fingers.

    • Adhere to policy for sample collection and handling to ensure accuracy.

22. Renal Function Tests

  • Blood Urea Nitrogen (BUN): Reflects protein metabolism; elevated levels indicate reduced kidney function.

  • Serum Creatinine: Waste from muscle metabolism, indicative of kidney filtering capacity.

23. Lipoprotein Profile

  • Purpose: Diagnoses hyperlipidemia and cardiovascular disease risk.

    • Cholesterol: Total amount of cholesterol in the blood.

    • LDL (Low-Density Lipoprotein): “Bad” cholesterol, high levels linked to atherosclerosis.

    • HDL (High-Density Lipoprotein): “Good” cholesterol, helps remove LDL, reducing heart disease risk.

    • Triglycerides: Stored fats, used as energy, high levels associated with increased cardiovascular risk.

24. Liver Function Tests

  • Albumin and Bilirubin: Assess protein production and waste clearance.

  • Liver Enzymes (ALT, ALP, AST, GGTP): High levels suggest liver cell damage from conditions like hepatitis or cirrhosis.

25. Cardiac Markers

  • Purpose: Identifies myocardial injury.

    • Creatine Kinase (CK) and CK-MB: Elevated levels indicate muscle damage, especially in the heart.

    • Myoglobin: Early marker of muscle damage.

    • Troponins I and T: Highly specific to cardiac tissue; elevated levels signal heart attack.

26. Urinalysis and Stool Analysis

  • Urinalysis: Routine test to detect UTIs, kidney disorders, and other conditions.

  • Stool Analysis: Assesses GI function, detects blood, fat, or parasites.

    • Cultures: Identify infectious agents in various fluids; guides antibiotic therapy by determining sensitivity.

27. Sputum Culture

  • Purpose: Diagnoses respiratory infections like pneumonia or tuberculosis.

    • Proper collection is critical to avoid contamination with saliva.

    • Specialized containers may be needed for TB or other specific pathogens.

28. Radiography and Contrast Studies

  • X-rays: Non-contrast images for bones and soft tissues; mammograms for breast cancer screening.

  • Contrast Studies: Used in IVP, Upper GI Series, and Barium Enema for enhanced detail; assess for allergies to contrast media (e.g., iodine).

  • Nurse’s Role: Monitor for allergic reactions, ensure adequate hydration, and promote barium elimination post-procedure.

29. MRI and ECG

  • MRI: Used for detailed imaging, particularly for brain and joint conditions; involves no radiation but may be contraindicated in patients with metal implants.

    • Claustrophobia can be an issue; sedation may be required.

  • EKG (ECG): Measures electrical activity of the heart, valuable in diagnosing arrhythmias and other cardiac issues.

30. Endoscopy and Ultrasound

  • Endoscopy: Directly visualizes organs (e.g., for biopsies); requires informed consent.

  • Ultrasound: Non-invasive imaging for soft tissues and fetal monitoring; utilizes sound waves to create real-time images.

31. Needle Aspirations

  • Purpose: Collects fluid or tissue samples with minimal invasiveness.

    • Paracentesis: Removes fluid from the abdomen.

    • Thoracentesis: Removes fluid from the pleural space.

    • Biopsy: Diagnoses cancer by sampling cells from a tumor or mass.