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35 Cards in this Set
- Front
- Back
What is the effect of non-depolarizing neuromuscular blocking agents on plasma potassium concentration?
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There is no effect
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What is the effect of succinylcholine on plasma potassium concentration?
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When Succinlycholine depolarizes muscles that have been previously traumatized or denervated, myoneural receptors proliferate over the cell membrane, and a depolarizing drug binding to the increased numbers of receptors can produce large increases in serum potassium leading to life-threatening arrhythmias and cardiac arrest
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What are the options for handling total parenteral nutrition (TPN) during the intraoperative period?
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Continue the TPN infusion or replace it with a D10 solution to prevent hypoglycemia
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During prolonged surgery, what laboratory tests should be monitored when a patient is receiving total parenteral nutrition (TPN)?
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Plasma glucose, potassium, and pH
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How much oxygen is dissolved in blood and under what conditions is this significant?
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0.003ml of O2 per 1mmHg PO2 is dissolved in 100cc of plasma. This contribution is insignificant when a normal hemoglobing is present. The situation changes is severely anemic patients
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What is the blood:gas partition coefficient for a volatile anesthetic?
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This is a ratio of the solubility of a volatile anesthetic in blood and air. For example, enflurane has a partition coefficient of 1.9 which means that at equilibrium there will be 1.9 times the concentration of inhaled agent in blood than in the gaseous (alveolar) phase.
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What is the goal of perioperative fluid management?
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To maintain intravascular volume, left ventricular filling pressures, CO, oxygen delivery to tissues, and systemic BP
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What quantitative fluid calculations are made in the perioperative period?
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Existing fluid deficits, maintenance fluids, and surgical fluid loss/3rd spacing
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Why is it essential to visualize blood loss intraoperatively?
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Surgeons tend to underestimate actual blood loss and signs of loss like tachycardia, acidosis, increasing base deficit, and decreased urine output are late signs
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What is the ratio of isotonic crystalloid replacement for blood loss?
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3 to 1
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What is the major disadvantage of hypotonic/isotonic crystalloids?
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They have a limited ability to remain in the intravascular space
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Why are hypotonic solutions generally avoided in the OR?
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Short half-life in the intravascular space and they can precipitate hyponatremia
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What negative outcomes can occur with large volumes of saline?
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Hyperchloremic-induced non-gap metabolic acidosis
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What negative outcomes can occur with large volumes of LR?
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Metabolic alkalosis because of increased bicarbonate production due to lactate metabolism
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What two solutions can increase potassium in hyperkalemic patients?
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Plasma-lyte and LR
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What is the difference between Dextran 70 and Dextran 40?
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Dextran 70 is preferred for volume resuscitation whereas dextran 40 improves blood flow to the microcirculation by decreasing blood viscosity
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What is pKa?
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The pH at which 50% of the substance is ionized
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Why do pediatric patients have greater insensible water, sodium, and heat losses?
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They have a greater body surface area to weight ratio
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What organ is the major regulator of water loss?
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The kidneys
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What is the best indicator of hypovolemia in the adult patient?
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Decreased blood pressure
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What is the best indicator of hypovolemia in the pediatric patient?
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Tachycardia
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What patients require intraoperative dextrose?
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Infants less than 1 month, neonates, infants of diabetic mothers, children with diabetes, those on hyperalimentation
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What causes a right shift in the oxygen hemoglobin dissociation curve?
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A right shift means that oxygen is delivered easily to tissues so acidosis, increased temperature, increased CO2, and increased 2,3-DPG
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What causes a left shift in oxygen hemoglobin dissociation curve?
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A left shift means a greater affinity of oxygen to hemoglobin so alkalosis, decreased CO2, decreased temperature, and decreased 2,3-DPG, and abnormal hemoglobins
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What happens to PaCO2 and PaO2 with increased temperatures?
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Both gases enter the gas phase so they increase
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What are two common and clinically relevant causes of metabolic alkalosis?
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Loss of gastric fluid and loss of acidic urine with diuretic therapy
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What is the acute respiratory compensatory response to metabolic alkalosis?
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Hypoventilation to increase PaCO2. Kidneys will eventually excrete bicarbonate.
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What happens to PaCO2 and PaO2 in an ABG sample with an air bubble?
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The gases try to equilibrate with each other. CO2 moves toward 0.
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What information is necessary for the accurate interpretation of a blood gas sample?
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Source of sample, temperature of sample, ventilator settings, FiO2
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How does apnea affect PaCO2?
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PaCO2 increases by 6mmHg in the first minute and by 3mmHg every minute after as apnea persists
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What happens to PaO2 and PaCO2 as dead space to tidal volume increases?
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Dead space is the area of ventilation without perfusion so PaO2 decreases and PaCO2 increases
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Metabolic alkalosis is frequently associated with what volume status change?
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Hypovolemia with marked sodium loss
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What percentage of total body water is in the ECF and ICF?
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ECF = 34-40% and 60-66%
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What is the most common underlying disorder in respiratory acidosis?
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Alveolar hypoventilation
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What are the possible adverse effects of hyperchloremia after a normal saline infusion?
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Metabolic acidosis, coagulopathies with bleeding, renal vasoconstriction, decreased GFR, and increased PONV
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