Drugs for Fluid and Electrolyte Imbalances, and Acid–Base Disorders Flashcards

1
Q

Body Fluid Compartments

A
  • Continuous exchange of fluids across Semipermeable Membranes between Intracellular & Extracellular Fluid compartments (Large molecules and those that are ionised are less able to cross membranes)
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2
Q

Indications for IV Therapy

A
  • Imbalances of
    1. Body Fluids
    2. Electrolytes
    3. Acid-Base
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3
Q

Definition of Osmolality

A

A colligative property of solutions that depends on the number of dissolved particles/solutes in the solution in 1kg (1L) of fluid
- Average osmolality is 275-295mOsm/kg

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4
Q

What does changes in Osmolality do?

A
  • If there are any changes in the Osmolality, it can cause water to more into different/another compartment
    (Sodium is the greatest contributor, and is controlled by Hormone Aldosterone)
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5
Q

How to regulate Fluid Intake and Output?

A
  1. Output
    - The kidneys regulate it with the Renin-Angiotensin-Aldosterone System (RAAS) and Antidiuretic Hormone (ADH)
  2. Input
    - Achieved through “Complex Mechanisms”
    - Most important regulator of Fluid Intake is “Thirst Mechanism”
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6
Q

2 types of Fluid Balance Disorders

A
  1. Deficient Fluid Balance Disorders
    - Can cause Dehydration and Shock
    - Treated with Oral or Intravenous Fluids
    - IV Therapy Fluid helps to maintain Blood Volume and Support Blood Pressure
  2. Excess Fluid Balance Disorders
    - Treated with Diuretics: Helps to reduce fluid buildup in the body (By helping the kidneys remove salt and water through urine)
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7
Q

How does IV Fluid Therapy help with Deficient Fluid Balance?

A
  • It replaces the fluid and electrolytes in the body by using Crystalloids and Colloids
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8
Q

5 Main Causes of Water and Electrolyte Loss

A
  1. Loss of GI Fluids due to vomiting, diarrhoea, chronic laxative use or GI suctioning
  2. Excessive sweating during hot weather, athletic activities, or prolonged fever
  3. Severe burns
  4. Haemorrhage (Loss of blood from damaged blood vessels)
  5. Excessive Diuresis (Increase in amount of Urine) due to Diuretic Therapy or Uncontrolled Diabetes Ketoacidosis
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9
Q

Crystalloids

A
  • Intravenous (IV) Solutions containing electrolytes, designed to closely mimic the body’s Extracellular Fluid (ECF), they replace Lost Fluids and promote Urine output
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10
Q

Example of IV Fluids (Solutions that move out of the plasma and into the interstitial spaces and intracellular fluid, depending on tonicity)

A
  1. Isotonic Solutions (e.g. 0.9% NaCl)
    - Expands plasma volume without causing fluid shifts between compartments
    - Indicated for treatment of fluid loss due to vomiting, diarrhoea or surgical procedures, especially when there is low BP
  2. Hypertonic Solutions (e.g. 3% NaCl)
    - Draws water cells and tissues into plasma, useful for treating Cerebral Oedema
    - Indicated for the release of Cellular Oedema
  3. Hypotonic Solutions (e.g. 0.45% NaCl)
    - Moves water from the plasma into cells and tissues, indicated for Hypernatremia and Cellular Dehydration
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11
Q

Adverse Effects of IV Solutions

A
  1. For Isotonic/Hypertonic Solutions
    - Fluid Overload (Excessive expansion of IV Compartments)
  2. For Hypotonic Solutions
    - Hypotension (Depletion of IV Compartment) and Peripheral Oedema (Too much expansion of Intracellular Compartment)
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12
Q

Colloids

A
  • Contain large molecules, such as proteins or starches, that are too large to easily pass through Capillary Membranes, keeping them in Intravascular Space
  • These solutions rapidly expand plasma volume by drawing water from intracellular fluid and interstitial space into plasma, increasing Osmotic Pressure
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13
Q

Selected Colloid Solutions

A
  1. Normal Serum Albumin (Most Common)
  2. Dextran (A Synthetic Polysaccharide), Infusion can double the plasma volume within a few minutes
  3. Hetastarch (A Synthetic Colloid), similar to 5% Albumin with extended duration of action
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14
Q

Adverse Effects of Colloids

A
  1. Usually Safe
  2. May caused Altered Coagulation (Disruptions in the body’s ability to control blood clotting), resulting in Bleeding
  3. (Rarely) Dextran Therapy causes Anaphylaxis or Renal Failure
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15
Q

Blood Products

A
  • Only class of fluids that carries Oxygen
  • Increases Tissue Oxygenation
  • Increases Plasma Volume
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16
Q

4 Indications for Blood Products

A
  1. Cryoprecipitate and Plasma Protein Factors (PPF)
  2. Fresh Frozen Plasma (FFP)
  3. Packed Red Blood Cells (PRBCs)
  4. Whole Blood
17
Q

Cryoprecipitate & Plasma Protein Factors (PPF)

A
  • Used for managing Acute Bleeding, especially with significant blood loss (Greater than 50% slow blood loss / 20% Acute blood loss)
18
Q

Fresh Frozen Plasma (FFP)

A
  • Administered to increase clotting factor levels in patients with clotting deficiencies
19
Q

Packed Red Blood Cells (PRBCs)

A
  • Indicated for increasing oxygen-carrying capacity in patients with Anemia, haemoglobin deficits, or those who have lost up to 25% of their total blood volume
20
Q

Whole Blood

A
  • Used similarly to PRBCs, but more beneficial for extreme blood loss (greater than 25%) because it contains plasma proteins, which helps draw fluid back into blood vessels from surrounding tissues
21
Q

4 Adverse Effects of Blood Products

A
  1. Incompatibility with the recipient’s immune system
    - Can cause transfusion reactions if blood type is crossmatched
  2. Anaphylaxis
    - A severe allergic reaction can occur, especially if the patient has had previous reactions to blood products
  3. Transmission of Pathogens
    - Although rare, there is a risk of transmitting infections, such as HIV, through contaminated blood
  4. Others
    - Crossmatch testing error and delayed transfusion reactions
22
Q

Electrolytes

A
  • Positively or Negatively charged inorganic molecules
  • Essential for
    1. Nerve conduction
    2. Membrane permeability
    3. Water balance
    4. Other critical body functions
23
Q

Electrolyte Imbalance

A
  • Shows a sign of an underlying condition / is associated with
    1. Renal Impairment
    2. Adverse Effects of Drugs (e.g. Loop Diuretics - Furosemides)
24
Q

Therapeutic goals when treating Electrolyte Imbalance

A
  1. Correct the Electrolyte Imbalance
  2. Diagnose and Treat underlying cause
25
Q

Sodium

A
  • A major electrolyte in Extracellular Fluid
  • Essential for maintaining osmolality, water balance, and acid-base balance
  • Water travels with / toward Sodium
  • Regulated by Kidney or Aldosterone
  • Sodium movement is linked to Water Retention, Blood Volume and Blood Pressure
26
Q

Hypernatremia

A
  1. Definition
    - Serum sodum levels >145mEq/L (High sodium levels)
  2. Causes
    - Renal diseases
    - High intake of Sodium through diet or Overtreatment with IV Fluids containing Sodium Chloride (NaCl)
    - Water loss, from inadequate intake, watery diarrhoea, fever, or burns
    - Use of high doses of Corticosteroids
  3. Pathophysiology
    - Elevated serum sodium increases plasma osmolality, drawing fluid from interstitial spaces and cells, leading to cellular dehydration
  4. Clinical Features
    - Thirst, Fatigue, Weakness, Muscle Twitching
    - (More severe cases) Convulsants, Altered Mental State, Decreased levels of Consciousness
  5. Management
    - Mild: Low-salt diet
    - Acute: IV Infusions of Hypotonic fluids
    - Hypovolemic: Diuretics
27
Q

Hyponatremia

A
  1. Definition
    - Serum sodium level <135mEq/L (Low sodium levels)
  2. Causes
    - Sodium loss through kidneys, GIT, Skin
    - Excessive dilution of plasma due to over-secretion of ADH or IV Infusion of Hypotonic Solution
  3. Clinical Features
    - Early: Nausea, Vomiting, Anorexia. Abdominal Cramping
    - Later: Confusion, Lethargy, Convulsions, Coma, Muscle Twitching, Tremors
  4. Management
    - For sodium loss: Oral sodium chloride or IV containing Salt (Normal Saline or Lactated Ringer’s)
    - For excessive dilution: Loop Diuretics to cause Isotonic Diuresis
28
Q

Hyperkalemia

A
  1. Definition
    - Serum Potassium levels >5mEq/L (High potassium levels)
  2. Causes
    - Renal diseases
    - High intake of Potassium, especially in patients on potassium-sparing diuretics
  3. Clinical Features
    - Dysrhythmias
    - Heart Block
    - Others: Muscle Twitching, Fatigue, Paresthesia, Dyspnea, Cramping, Diarrhoea
  4. Management
    - Mild: Restrict dietary potassium (e.g. bananas, citrus, dried fruits), Adjust or Substitute Potassium-sparing Diuretics with Thiazide or Loop Diuretics
    - Severe: Administer IV Glucose and Insulin, Albuterol Nebuliser, and Calcium Gluconate to counteract potassium toxicity to heart
29
Q

Hypokalemia

A
  1. Definition
    - Serum potassium levels <3.5mEq/L (Low potassium levels)
  2. Causes
    - High doses of Loop Diuretics
    - Strenuous muscle activity
    - Severe vomiting or Diarrhoea
  3. Clinical Features
    - Muscle weakness, Lethargy, Anorexia
    - Dysrhythmias, Potential Cardiac Arrest
  4. Management
    - Mild: Increase dietary intake of potassium
    - Severe: Administer Oral or Parenteral Potassium Supplements
30
Q

Regulating Acid-Base Balances

A
  • Chemicals help to neutralise body;s strong acid and bases
  • Bicarbonate and Phosphate Ions
31
Q

2 Mechanisms to Remove acid from body

A
  1. Removal of carbon dioxide (CO2) through the lungs
  2. Removal of H+ (Hydrogen) ions through the Kidney
32
Q

Causes of Alkalosis

A
  1. Respiratory Origins
    - Hypoventilation / Shallow breathing
    - Airway Constriction
    - Damage to Respiratory Centre in Medulla
  2. Metabolic Origins
    - Starvation
    - Excess Alcohol Consumption
    - Diabetes Mellitus (DM)
    - Kidney Failure
    - Severe Diarrhoea
33
Q

Causes of Alkalosis

A
  1. Respiratory Origins
    - Hyperventilation (Due to Asthma, Anxiety, or High Altitude)
  2. Metabolic Origins
    - Constipation for prolonged periods
    - Ingestion of excess Sodium Bicarbonate
    - Diuretics that causes Potassium Depletion
    - Severe Vomiting
34
Q

Pharmacotherapy of Acidosis

A
  1. Symptoms affects CNS depression
    - Lethargy, Confusion, Coma
    - Deep, Rapid Respirations in attempt to blow off excess acid in Metabolic Acidosis
  2. Treatment
    - Quickly reverse effects of excess acid in blood
    - Administration of Sodium Bicarbonate Infusion
35
Q

Pharmacotherapy for Alkalosis

A
  1. Symptoms due to CNS Stimulation
    - Nervousness, Hyperactive Reflexes, Convulsions,
    - Slow, Shallow Respirations in attempt to retain Acid in Metabolic Alkalosis
  2. Treatment
    - Administration of Sodium Chloride with Potassium Chloride (For Mild Cases)
    - Administration of Ammonium Chloride (For Severe Cases)