Respiratory review part 1

Question 1

a decrease in body pH causes what?

Answer 1

acidosis, which stimulates ventilation (an increase in the rate and/or depth of breathing).

Question 2

a decrease in PaO2 causes what?

Answer 2

hypoxemia, which results in an increase in the rate and/or depth of breathing.

chronic PaCO2 retainers (emphesema) rely on mild hypoxemia for ventilator drive. If the PaO2 is corrected to normal, this may result in a decreased drive to breathe (ventilate).

Question 3

What is the clinical indicator of ventilation? How do you know your patient is ventilated normally?

Answer 3

PaCO2 (NOT PaO2)

Question 4

what is minute ventilation?

Answer 4

tidal volume (Vt) x respiratory rate (RR)

normal is 4 L/min

an increase in minute ventilation = an increase in work of breathing

Question 5

what is the primary muscle of ventilation?

Answer 5

diaphragm

Question 6

what is the position for optimal ventilation?

Answer 6

upright sitting position

supine is NOT good for ventilation

Question 7

a pulmonary embolus results in increased alveolar ____.

Answer 7

dead space.

Question 8

any decrease in blood flow past alveoli (pulmonary embolus, low cardiac output) will affect the ____.

Answer 8

ventilation-perfusion ratio and gas exchange.

Question 9

normal ventilation-perfusion ratio

Answer 9

4 L ventilation/min(V) / 5 L perfusion/min(Q)

=0.8 V/Q ratio

Question 10

A patient has pneumonia. What position should the patient be placed in?

Answer 10

“good” lung down.

if the patient is turned to the “bad” lung down then the patient will become more hypoxemic.

Question 11

what is a V/Q mismatch?

Answer 11

when there is a problem with ventilation or perfusion.

Question 12

what is a shunt?

Answer 12

movement of blood from the right side of the heart to the left side of the heart without getting oxygenated. (venous blood moves to the arterial side)

examples: Ventricular septal defect, atrial septal defect, or ARDS (pathologic)

Question 13

ARDS

Answer 13

blood goes through the lungs but does NOT get oxygenated.

treatment: oxygen and PEEP (positive end-expiratory pressure)

Question 14

what is the evidence of insufficient oxygen at the cellular level?

Answer 14

Lactic acid (lactic acidosis)

Question 15

oxyhemoglobin dissociation curve shift to the LEFT

Answer 15

hemoglobin holds onto oxygen molecules (SaO2 is high but O2 is stuck to hgb)

alkalosis, low PaCO2
hypothermia

remember: Left is aLkaLosis, coLd, Low

Question 16

oxyhemoglobin dissociation curve shift to the RIGHT

Answer 16

hemoglobin releases oxygen more easily to the tissue

Good for tissues; SaO2 is low but O2 is easily released to the tissues

acidosis, High PaCO2, fever

Question 17

what is lung compliance?

Answer 17

the degree of elasticity of tissue

Question 18

static compliance:

Answer 18

measurement of the elastic properties of the LUNG (tidal volume / plateau pressure)

Question 19

dynamic compliance

Answer 19

measurement of the elastic properties of the AIRWAYS (tidal volume/peak inspiratory pressure)

Question 20

anion gap

Answer 20

5-15 mEq/L

difference between (+) and (-) anions.

helpful in determining the response to treatment for metabolic acidosis

Question 21

problems associated with an increased anion gap acidosis (think “Kussmaul”)

Answer 21

Ketoacidosis
Uremia
Salicylate intoxication
Methanol toxicity
Alcoholic ketosis
Unmeasured osmoses
Lactic acidosis

Question 22

problems associated with a normal anion gap acidosis

Answer 22

Saline infusion (hyperchloremic acidosis)
TPN
Diarrhea
Acute renal failure, sometimes chronic

Question 23

pH
PaCO2
HCO3

Answer 23

7.35-7.45
35-45
22-26