Module 4 PP. Perioperative Crystalloids Quiz

Electrolytes and Minerals

• Sodium is primarily found in the extracellular fluid (ECF)
• Normal levels range from 135-145 mEq/L
• Functions include water balance, osmotic pressure control, nerve impulse conduction, and muscle contraction

Sodium Alterations

• Sodium intake comes from diet and intravenous fluids

• Homeostasis is maintained by the kidneys, reabsorbing most filtered sodium

• Hormones like RAAS, ADH, and SNS regulate BP and intravascular volume

• Parathyroid hormone and natriuretic peptides stimulate sodium excretion

• Hyponatremia:

  • Can be caused by hypervolemia (e.g., CHF, cirrhosis) or hypovolemia (e.g., diarrhea, vomiting)
  • Other causes include salt wasting or euvolemia (e.g., adrenal insufficiency, polydipsia)
  • Symptoms include nausea, vomiting, muscle cramps
  • Treatment depends on the underlying cause

• Hypernatremia:

  • Caused by water loss (e.g., fever, sweating, osmotic diuresis)
  • Other causes include nephrogenic or central diabetes insipidus, or excessive sodium administration.
  • Symptoms may include dehydration signs, altered mental status, seizures, or coma
  • Treatment depends on the underlying cause

Potassium

• Primarily found intracellularly (98%)
• Normal levels range from 3.5-5.2 mEq/L
• Functions include cell membrane excitability (nerves, muscles, heart), kidney function, and influences osmotic pressure
• Affects endothelial-dependent vasodilation, thrombus formation, and platelet activation

Potassium Alterations

• Hypokalemia:
  • Can be caused by diuretics, beta agonists, insulin, antibiotics, catecholamines
  • Also results from GI losses (e.g., laxatives, bowel prep)
  • Symptoms include muscle weakness, muscle cramps, rhabdomyolysis, ileus, nausea, vomiting, and dysrhythmias
    • These include T wave inversion, U waves, tachyarrhythmias (torsades, AFib)
• Hyperkalemia:
  • Caused by potassium redistribution or inhibition of secretion (e.g., medications like SCh, digitalis), aldosterone antagonists, beta antagonists, NSAIDs, chemotherapy, and PRBC transfusion.
  • Symptoms include paresthesias, muscle weakness, widened QRS complexes, prolonged PR intervals, and cardiac conduction blockade leading to VF and asystole

Magnesium

• Primarily intracellular (bone, muscle, soft tissues)
• Normal levels range from 1.7-2.4 mg/dL
• Functions include protein synthesis, nucleic acid stability, neuromuscular function, muscle relaxation, antiarrhythmic effects, vasodilation, stabilization of the BBB, and reducing anesthetic requirements

Magnesium Alterations

• Hypomagnesemia:
  • Caused by dietary deficiency, GI malabsorption (e.g., alcoholism, vomiting, laxatives), and renal losses (e.g., diuretics, nephropathy)
  • Symptoms include prolonged PR and QT intervals, diminished T waves, torsades, arrhythmias, weakness, tetany, fasciculations, convulsions, nausea, and vomiting
• Hypermagnesemia:
  • Caused by excessive magnesium administration
  • Symptoms include widened QRS complexes, conduction blockade, asystole, hypotension, respiratory depression, muscle paralysis, diminished reflexes, and narcosis

Calcium

• Predominantly stored in the skeleton
• Normal levels range from 8.5-10.5 mg/dL
• Functions include musculoskeletal strength, neuromuscular transmission, cardiac muscle contractility, relaxation, and rhythm; vascular motor tone, and intracellular signaling
• Homeostasis is maintained by endocrine control through vitamin D, parathyroid hormone, and calcitonin; regulating intestinal absorption, renal reabsorption, and bone turnover

Calcium Alterations

• Hypocalcemia:
  • Can be caused by decreased albumin, vitamin D deficiency, or disorders like hypoparathyroidism, pancreatitis, chronic renal failure, and citrate binding during transfusions.
  • Symptoms include neuromuscular issues such as twitching, spasms, paresthesias, tetany, seizures, and dysrhythmias
• Hypercalcemia:
  • Caused by disorders like hyperparathyroidism, or parathyroid adenoma
  • Additional causes include malignancies, excessive dietary supplementation, or medication-induced issues (e.g., diuretics, lithium)
  • Symptoms include GI smooth muscle relaxation (nausea, vomiting, constipation), decreased neuromuscular transmission (lethargy, hypotonia), polyuria, dehydration, renal stones, and shortened QT intervals

Phosphate

• Primarily intracellular (bone, soft tissue)
• Normal level range 3-4.5 mg/dL
• Functions include energy metabolism, intracellular signaling (cAMP), immune system regulation, coagulation cascade regulation, and acid-base balance

Fluid Compartments

• Body fluid is primarily composed of intracellular (2/3) and extracellular fluid (1/3)
• Extracellular fluid is primarily interstitial (~80%) and plasma (~20%)

Plasma Composition

• Primarily water (90%)
• Contains proteins (albumin, globulins) with roles in oncotic pressure, transport, pH, and coagulation
• Electrolytes and small molecules like salts, nutrients, waste products, hormones, and blood cells are in <1% concentration

Compartmental Fluid Movement

• Small ions readily move between plasma and interstitial fluid
• Larger molecules are prevented from free movement by tight junctions of endothelial cells and the endothelial glycocalyx layer

Monitoring Intravascular Volume Status

• Static parameters: Blood pressure, heart rate, urine output, mixed venous oxygen saturation are assessed but may lack sensitivity for identifying fluid imbalances
• Dynamic parameters: Respiratory variations in arterial waveform, end-expiratory occlusion test, ultrasound technologies (esophageal doppler, echocardiography) are helpful to assess fluid responsiveness but can have limitations in specific conditions

Crystalloids

• Crystalloid solutions contain soluble electrolytes and small molecules
• Classified by tonicity: Isotonic (e.g., 0.9% NaCl, Lactated Ringers), Hypotonic (e.g., 0.45% NaCl), Hypertonic (e.g., Dextrose 5% in NS)
• Isotonic solutions contain electrolytes similar to extracellular fluid and remain in the blood vessels

Colloids

• Colloids contain large molecules
• Examples: Albumin, Hydroxyethyl Starches (HES)
• Used for expansion of intravascular volume

Blood Physiology and Blood Transfusion

• Red blood cells: Essential for oxygen transport
• White blood cells: Part of the immune system
• Platelets: Crucial for hemostasis

Anemia and Iron Deficiency

• Anemia is a reduced RBC/hemoglobin count
• Iron deficiency is a possible cause of anemia

Transfusion-Associated Complications

• TACO: Transfusion-associated circulatory overload
• TRALI: Transfusion-related acute lung injury
• Citrate toxicity: Risk from citrate use in stored blood
• Agglutination: Antibodies in recipient reacting with antigens on donor blood

Massive Transfusion

• Associated with life-threatening, uncontrolled bleeding
• Severe complications including coagulopathy and hypothermia

Coagulopathy Management

• Aims to correct coagulation abnormalities that arise through interventions including transfusion or other treatments