Fluid and Electrolyte Disorders Flashcards
Causes of hypovolemia?
- GI losses (bleeding, NG suction, vomiting, diarrhea)
- Salt and water loss: diuretics
- Water loss: diabetes insipidus
- Skin losses: sweat, burns
- Sequestration without loss
- Intestinal obstruction, pancreatitis, rhabdomyolysis
- Hemorrhage/bleeding
What are the clinical presentations of hypovolemia?
- Increased thirst, decreased sweating
- Decreased skin turgor & dry mucus membranes
- Oliguria with increased urine concentration
- CNS depression
- Weakness and muscle cramps
- Decreased BP; postural hypotension/dizziness
- Increased pulse; postural pulse increase
Causes of hypervolemia?
- Acute or chronic renal failure
- Nephrotic syndrome
- Primary hyperaldosteronism
- Cushing’s syndrome
- Liver disease
- Heart failure
- Pregnancy
What are the clinical presentations of hypervolemia?
- Edema
- Shortness of breath
- Orthopnea, paroxysmal nocturnal dyspnea (PND)
- Jugular venous distension
- Hepatojugular reflux
- Crackles on pulmonary exam
Primary respiratory problem involves what?
PCO2
Primary metabolic problem involves what?
HCO3
What are the causes of respiratory alkalosis?
- Hyperventilation (anxiety = most common)
- Compensatory mechanism in sepsis
- Pain
- CNS (neurogenic hyperventilation)
- Salicylate overdose
- Pregnancy
- High altitude
- Hypoxemia
- Hepatic encephalopathy
What are the S+S of respiratory alkalosis?
- Lightheadedness
- Palpitations
- Tachypnea
- +/- paresthesias
What are the causes of respiratory acidosis?
- Acute airway obstruction: foreign body, tumor, laryngospasm/bronchospasm
- Lung disease: Severe pneumonia/PE/COPD exacerbation, pulmonary edema, pulmonary fibrosis
- CNS depression: drugs (narcotics), CNS event, trauma, central sleep apnea
- Neuromuscular disorder: Guillan-Barre, Myasthenia Gravis, Brain Stem or Spinal Cord Injury
- Impaired lung motion
- Inappropriate mechanical ventilation settings.
What are the causes of metabolic alkalosis?
*Check urine chloride
Urine chloride < 25 is chloride responsive type:
- GI losses like vomiting, NG suction
- Diuretics (“contraction alkalosis”)
- Cystic Fibrosis
Urine chloride <>25 is non-chloride responsive type:
- Barter’s syndrome
- Cushing’s
- Hyperaldosteronism
- Potassium depletion
- Citrate toxicity for massive blood transfusion protocol
- Chronic diuretics
- Renin secreting tumor
How to treat chloride responsive metabolic alkalosis?
Give fluids
How to treat non-chloride responsive metabolic alkalosis?
Tx underlying cause. May need to give potassium
What are the causes of metabolic acidosis?
High anion gap: “MUDPILES” -Methanol -Uremia -DKA -Propylene Glycol -Iron/Isoniazid -Lactate (lactic acidosis) -Ethanol/ethylene glycol -Salicylates/starvation
Non-anion gap:
- GI bicarbonate loss: Diarrhea, GI fistulas, ureterosigmoidostomy
- Renal bicarbonate losses: Early renal failure, Rental tubular acidosis (RTA), Carbonic anhydrase inhibitors (acetazolamide), Aldosterone inhibitors (spirinolactone)
- Hyperchloremia due to saline resuscitation.
What are some physiological things that happen with acidosis?
- Myocardial depression
- Sympathetic overactivity (tachycardia, vasoconstriction, increased arrhythmias)
- Resistance to catecholamines
- Peripheral arteriolar vasodilation
- Peripheral venoconstriction
- Pulmonary artery constriction
- Potassium shift out of cells, effect on myocytes
- Hyper-ventilation & Increased WOB
- Shift of oxy-hemoglobin dissociation curve
- Cerebral vasodilation, increased ICP
- Central depression with high pCO2
What are some physiological things that happen with alkalosis?
- Decreased respiratory drive
- Shift of oxyhemoglobin curve (impaired O2 unloading)
- Depression of myocardial contractility
- Arrhythmias
- Potassium shift into the cells (hypokalemia)
- Cerebral vasoconstriction → decrease in cerebral blood flow
- Increased NM excitability
