gas exchange

Question 1

pulmonary gas exchange steps

Answer 1

step 1: ventilation
step 2: respiration.
step 3: transport of gases in the circulation

Question 2

reasons for V/Q < 0.8

Answer 2

a) A decrease in ventilation in relation to perfusion has occurred.
b) Similar to right to left shunt
c) Mucous plug

Question 3

reasons V/Q > 0.8

Answer 3

a) a decrease in perfusion in relation to ventilation
b) pulmonary emboli, cardiogenic shock

Question 4

PaO2 normal range
SaO2 normal range
When do patients have hypoxemia
what level of PaO2 is life threatening

Answer 4

PaO2: 80-100
SaO2: 95-100%
HYPOXEMIA: PaO2 <60
PaO2 <40 is life threatening

Question 5

explain shunting in the lung

Answer 5

Blood shunted past the lung and returns unoxygenated blood to left side of heart

Question 6

causes of shunting

Answer 6

AVMs, ARDS, atelectasis, pneumonia, pulmonary edema, pulmonary embolus, vascular lung tumors, intra-cardiac right to left shunts

Question 7

causes of metabolic alkalosis

Answer 7

-vomiting
-NG suctioning
-diuretic therapy
-hypokalemia
-excess NaHCO3 intake
-mineralocorticoid use

Question 8

clinical manifestations of metabolic alkalosis

Answer 8

-irritability, lethargy, confusion, headache
-tachycardia, dysrhythmias r/t hypokalemia
-nausea, vomiting, anorexia
-tetany, tremors, tingling of fingers and toes, muscle cramps, hypertonic muscles, seizures
-hypoventilation

Question 9

management of metabolic alkalosis

Answer 9

treat underlying cause

Question 10

causes of respiratory alkalosis

Answer 10

-hyperventilation (hypoxia, anxiety, pain, fever, exercise)
-stimulated respiratory center (septicemia, stroke, meningitis, encephalitis, brain injury, salicylate poisoning)
-liver failure
-mechanical hyperventilation

Question 11

clinical manifestation of respiratory alkalosis

Answer 11

-dizziness, confusion, headache
-tachycardia, dysrhythmias r/t hypokalemia
-nausea, vomiting, diarrhea, epigastric pain
-tetany, numbness, tingling of extremities, hyperreflexia,
seizures

Question 12

metabolic compensation for respiratory alkalosis

Answer 12

decreased hydrogen secretion and bicarbonate reabsorption

Question 13

management of respiratory alkalosis

Answer 13

-discontinue or treat underlying cause
-decrease excessive ventilation if possible (hyperventilation-encourage breath holding, breath into paper bag)
-if acute hypoxemia, oxygen therapy

Question 14

causes of metabolic acidosis

Answer 14

-diabetic ketoacidosis
-Lactic acidosis
-Starvation
-Diarrhea
-Renal tubular acidosis, renal failure
-GI fistulas
-Shock/sepsis

Question 15

clinical manifestation. of metabolic acidosis

Answer 15

• lethargy, confusion, dizziness, headache, coma
  -hypotension, dysrhythmias (r/t hyperkalemia), cold/clammy skin
  -warm, flushed skin (peripheral vasodilation)
  -nausea, vomiting, diarrhea, abd pain
  -deep, rapid respirations

Question 16

respiratory compensation for metabolic acidosis

Answer 16

increased respiratory rate and depth (Kussmaul respirations)

Question 17

management of metabolic acidosis

Answer 17

-treat underlying cause
–administer sodium bicarbonate (extreme metabolic acidosis pH<7.1
-treat DKA with insulin and IV fluids
-decrease acid formation (decrease lactic acid production by improving CO in shock)
-treat kidney disease or toxic medication with dialysis

Question 18

causes for respiratory acidosis

Answer 18

-Chronic respiratory disease (respiratory failure related to: COPD, ARDS, severe asthma)
-Barbiturate or sedative overdose
-CNS depression (head trauma, anesthesia, barbiturate or sedative overdose, oversedation, high spinal cord injury)
-Chest wall anomaly, atelectasis, pneumothorax
-Severe pneumonia
-Respiratory muscle weakness (myasthenia gravis, multiple sclerosis)
-Mechanical ventilation hypoventilation
-Pulmonary edema

Question 19

clinical manifestation of respiratory acidosis

Answer 19

-drowsiness, lethargy, confusion, dizziness, headache
-hypotension, ventricular fib (r/t hyperkalemia), warm flushed skin
-seizures
-decreased respiratory rate and depth of breathing, hypoxia

Question 20

renal compensation for respiratory acidosis

Answer 20

-increased hydrogen secretion and bicarbonate reabsorption

Question 21

management of respiratory acidosis

Answer 21

-correct/improve ventilation and lung expansion
(supplemental oxygen, bronchodilators, cough & deep breath, incentive spirometry, ambulation, BiPAP or CPAP, intubation with mechanical ventilation)
-treat underlying cause
-chest physiotherapy, suctioning to clear secretions