Medications Used to Treat Thromboembolic Disorders

Fundamentals of Thromboembolic Disorders and Clinical Judgment

• Thromboembolic Definitions:     - Hemostasis: The process where a thrombus seals a hole in a blood vessel to stop bleeding.     - Coagulation: The process of blood clot formation.     - Thrombus: A blood clot that remains stationary in one location.     - Embolus: A "traveling" blood clot that has moved from its point of origin.     - Hemorrhage: Excessive bleeding that occurs if the body fails to coagulate.     - Thromboembolic Disorders: Diseases characterized by the formation of unwanted blood clots, which can lead to tissue or organ death by cutting off oxygenation.

• Six Clinical Judgment Elements (NCLEX Preparation):     1. Recognize Cues: Identifying the symptoms currently visible in the patient.     2. Analyze Cues: Determining the significance and meaning of those symptoms.     3. Prioritize Hypotheses: Assessing the urgency of the situation and the potential consequences of inaction.     4. Generate Solutions: Deciding on the appropriate course of action or intervention.     5. Take Actions: Implementing interventions correctly to assist the client.     6. Evaluate Outcomes: Identifying signs that indicate whether the patient's status is improving, declining, or remaining unchanged.

• Clinical Communication (SBAR Example):     - Situation: Identifying the nurse, the patient (Joe Taylor, $46$-year-old male), and the primary issue (admitted with DVT in the right lower leg).     - Background: Patient was on heparin infusing at $1,200\,\text{units/hr}$; dose was increased $3\,\text{hours}$ ago. Developed severe ecchymosis to the left knee and lower leg (new finding). Vital signs are stable; no other bleeding evidence. Heparin drip was stopped; next PTT not due for $3\,\text{hours}$.     - Assessment: Indication that the heparin dose was too high, resulting in signs of bleeding.     - Recommendation: Keep heparin off, request an immediate PTT, and request an injection of protamine sulfate.

The Physiological Process of Blood Clotting

• Step #1: Platelet Aggregation:     - Thrombocytes (Platelets): Abbreviated as "PLTS". These are "sticky cells" that stick together to form a platelet plug.     - Normal Platelet Count: $150,000 - 400,000$ per microliter (found on a Complete Blood Count/CBC).     - Thrombocytopenia: A condition characterized by too few platelets in the bloodstream.

• Step #2: Activated Clotting Factors (Clotting Cascade):     - Chemicals called clotting factors are produced by the liver and become activated.     - These factors join the platelet plug to facilitate coagulation.     - Vitamin K: Essential for the production of several clotting factors; high Vitamin K levels correlate with increased clotting ability.

• Step #3: Fibrin Formation:     - The final step involves the thrombus being "tied up" with a string called fibrin.     - Fibrin: Formed from the clotting factor fibrinogen. It creates a mesh that holds the clot together.

Pharmacological Interventions for Clotting

• Stage 1 Inhibitors (Platelet Aggregate Inhibitors/Antiplatelets):     - Prevent platelets from sticking together to form a plug.     - Medications:         - aspirin (PO; administered by RN, LPN)         - clopidogrel (PO; administered by RN, LPN)

• Stage 2 Inhibitors (Anticoagulants/Blood Thinners):     - Prevent the activation of clotting factors or the clotting cascade.     - Medications:         - heparin (SQ; administered by RN, LPN)         - heparin IV drip (administered by LPN with RN supervision)         - enoxaparin (SQ; administered by RN, LPN)         - warfarin (PO; administered by RN, LPN)         - apixaban (PO; administered by RN, LPN)         - rivaroxaban (PO; administered by RN, LPN)

• Stage 3 Inhibitors (Thrombolytics/Fibrinolytics/"Clot Busters"):     - Destroy the fibrin string to "bust up" existing, life-threatening clots.     - Medications (Administered by RNs in ER/ICU):         - Retavase (IV)         - Alteplase (IV)

Specific Anticoagulant Administration Procedures

• Subcutaneous Heparin Sodium:     - Site: Abdominal fat, at least $2\,\text{inches}$ from the umbilicus.     - Needle Specifications: Length of $1/2\,\text{inch}$ or $3/8\,\text{inch}$; Gauge of $25$, $27$, or $29$.     - Angle: $45\,\text{degrees}$.     - Post-Injection Care: Apply gentle pressure; do not massage the site to avoid bruising. Rotate sites to prevent lipodystrophy.     - Calculation Example:         - Ordered: $5,000\,\text{units}$         - Available: $10,000\,\text{units/mL}$         - Formula: $\frac{5,000\,\text{units}}{10,000\,\text{units}} \times 1\,\text{mL} = 0.5\,\text{mL}$

• Enoxaparin Sodium:     - Site/Specs: Same as Heparin (Abdominal fat, $45\,\text{degree}$ angle, $25-29$ gauge).     - Special Instruction: Comes in a prefilled syringe. Do Not expel the air bubble; it ensures the medication stays in the fat and does not leak out.

• Warfarin (Coumadin):     - Route: PO.     - Characteristics: Older, inexpensive, highly effective but high risk for bleeding because it inhibits the synthesis of multiple Vitamin K-dependent clotting factors.     - Dietary Restrictions: Client must maintain a consistent intake of Vitamin K foods (green leafy vegetables). Large increases in Vitamin K will thicken the blood and counteract warfarin.     - Monitoring: Requires monthly blood work (PT/INR).

• Newer Oral Anticoagulants (apixaban, rivaroxaban, dabigatran):     - Route: PO.     - Mechanism: Inhibits only one clotting factor (rather than many), reducing bleeding risk.     - Advantages: No routine blood work (PT/INR) required; no dietary restrictions.     - Disadvantage: More expensive than warfarin.

Coagulation Monitoring and Dosage Adjustment

• Standard Normal Values (No Medication):     - PTT (Partial Thromboplastin Time): Approx. $30\,\text{seconds}$.     - PT (Prothrombin Time): Approx. $15\,\text{seconds}$.     - INR (International Normalized Ratio): $1.0$.

• Heparin IV Titration (Based on PTT):     - Therapeutic Goal: PTT should be $1.5 - 2.5$ times higher than normal ($45 - 75\,\text{seconds}$).     - PTT < 45 seconds: Risk of clotting; RN titrates dose up.     - PTT 45 - 75 seconds: Therapeutic; dose remains the same.     - PTT > 75 seconds: Risk of bleeding.         - If no bleeding: RN titrates dose down.         - If bleeding occurs: STOP infusion; RN administers antidote (Protamine Sulfate).

• Warfarin Titration (Based on PT/INR):     - Therapeutic Goal: PT should be $1.5 - 2.0$ times higher ($22 - 30\,\text{seconds}$); INR should be $2.0 - 3.0$.     - Result Below Therapeutic Range (e.g., INR 1.6): Risk of unwanted clot. Provider titrates dose upward. Assessment: Check for high Vitamin K intake or non-compliance (skipping doses).     - Result Above Therapeutic Range (e.g., INR 3.9 or 4.2): Risk of bleeding.         - Step 1: Assess for bleeding.         - If no bleeding: Provider titrates dose down or "holds" the dose for a few days.         - If bleeding occurs: Hold medication and administer antidote (Vitamin K).

Patient Education and Safety

• General Safety Precautions:     - Hold pressure longer on cuts due to slowed clotting.     - Wear a medical alert bracelet.     - Avoid sharp objects (knives, scissors) and injury-prone sports.     - Use an electric razor instead of a straight-edge razor.     - Use a soft-bristled toothbrush.
• Surgical Consideration: Medications that prolong clotting must be held for one week prior to surgery.

Assessment of Bleeding and Hemorrhage

• Integumentary Signs:     - Ecchymosis: Bruising (blood under the skin).     - Purpura: Excessive bruising.     - Petechiae: Small dots caused by capillaries leaking blood.     - Hematoma: A raised pocket of blood under the skin.

• Specific Bleeding Sites:     - Epistaxis: Nosebleed.     - Hematuria: Bloody urine.     - Melena: Black, tarry, sticky stool indicating old blood.     - Hematochezia: Fresh, bright red blood in the stool.     - Hematemesis: Fresh blood in the vomit.     - Coffee-ground emesis: Old, digested blood in the vomit.     - Hemoptysis: Bloody sputum.

• Hidden Blood Testing:     - Known as Hemoccult, fecal occult blood (FOB), or Guaiac stool test.     - A blue color after adding developer indicates a positive result for hidden blood.

• Vital Sign and Lab Indicators of Excessive Blood Loss:     - Hypotension: Decreased Blood Pressure (BP $\downarrow$).     - Tachycardia: Increased Heart Rate (HR $\uparrow$).     - Tachypnea: Increased Respiratory Rate (RR $\uparrow$).     - Physical Appearance: Pallor (pale), Clammy (cold, wet skin).     - Neurological: New onset confusion, lethargy.     - Circulation: Weak, thready pulses ($+1$), flattened veins.     - Lab Values Indicating Loss:         - RBC (Erythrocytes): Less than $4\,\text{million}$.         - Hemoglobin (HGB): Less than $12\,\text{g/dL}$.         - Hematocrit (HCT): Less than $36\%$.