Respiratory

Question 1

Hypoxia

Answer 1

Decrease in level of oxygen supply to tissues

Question 2

Hypoxemia

Answer 2

Inadequate oxygenation of arterial blood

PaO2 less than 80mmHg (at sea level) or SaO2 or SPO2 of less than 95%

Question 3

DO2

Answer 3

Delivery of oxygen to tissues

DO2 = CO x CaO2

Question 4

General reasons for hypoxemia

Answer 4

hypoventilation, ventilation perfusion mismatch, diffusion impairment, decreased oxygen content of inspired air, and intrapulmonary shunt

Question 5

How is arterial oxygen delivered to tissues?

Answer 5

Bound to hemoglobin
Small fraction (0.003 x PaO2) is delivered unbound or dissolved in plasma

Question 6

Nasal or transtracheal oxygen flow rate

Answer 6

50-150mL/kg/min

Question 7

Five phases of oxygen toxicity

Answer 7

Initiation
-Free radicals cause damage to pulmonary epithelial cells and antioxidants become depleted
-24-72 hours of exposure to 100% oxygen
Inflammation
-Destruction of pulmonary epithelial lining causes airway inflammation and recruitment of activated inflammatory cells
-Release of inflammatory mediators causing increased permeability and development of pulmonary edema
Destruction
-Local destruction most commonly associated with patient mortality
Proliferation
-Type II pneumocytes and monocytes increase
Fibrosis
-Collagen deposition and interstitial fibrosis results in permanent damage to lungs

Question 8

Retrolental fibroplasia

Answer 8

Retinal lesion seen in neonates after oxygen toxicosis

Question 9

PaO2 <60mmHg or SaO2 or SpO2 <90%

Answer 9

Severe, potentially life-threating hypoxemia

Question 10

PaO2

Answer 10

• Partial pressure of oxygen dissolved in plasma of arterial blood
• Measure of ability of lungs to move oxygen from atmosphere to the blood
• Normal PaO2 at sea level between 80-110mmHg

Question 11

SaO2

Answer 11

Hemoglobin saturation with oxygen

Question 12

SpO2

Answer 12

Pulse oximeter hemoglobin oxygen saturation

Question 13

Commonly cited number for concentration of deoxygenated hemoglobin before cyanosis is present

Answer 13

5g/dL

Question 14

Hypoventilation

Answer 14

elevated PaCO2 (45mmHg or higher) or elevated ETCO2 (5mmHg lower than PaCO2) or central venous PCO2 (5mmHg higher than PaCO2)

Question 15

When can hypoventilation be eliminated as a cause of hypoxemia?

Answer 15

When the patient is breathing supplemental oxygen

Question 16

Four causes of venous admixture

Answer 16

Low ventilation perfusion regions
Regions of zero ventilation/perfusion
Diffusion defects
Right to left shunting

Question 17

Venous admixture

Answer 17

All the ways in which venous blood can get from right side to left side of circulation without being properly oxygenated

Question 18

The 120 Rule

Answer 18

PaCO2 + PaO2 = 120 if lungs functioning normally

Used at room air at sea level

Question 19

PaO2/FiO2 ratio

Answer 19

Compensates for variation in A-a gradient due to inspired oxygen
Use only if on supplemental oxygen
Normal = 500mmHg

Question 20

Anatomic dead space

Answer 20

Upper airway, trachea, lower airway, to level of terminal bronchioles

Question 21

Alveolar dead space

Answer 21

Inspired gas passing through anatomic dead space and mixing with gas in alveoli but no gas exchange

Question 22

Physiologic dead space

Answer 22

Combination of anatomic and alveolar dead space - all portions of tidal volume not participating in gas exchange

Question 23

In healthy lungs the amount of anatomic and physiologic dead space should be

Answer 23

Roughly equal

Question 24

In diseased lungs with a ventilation perfusion mismatch - the amount of physiologic dead space ?

Answer 24

Increases

Question 25

Bordetella bronchiseptica

Answer 25

Gram negative bacterium
Extracellular
Attaches to tracheal cilia
Most common bacterial agent in infectious tracheobronchitis
Treat with aerosolized gentamicin

Question 26

How is tracheostomy tube size selected

Answer 26

Measurement of the tracheal lumen on radiograph

Question 27

When placing a tracheostomy tube, what is a possible complication of inappropriate dissection?

Answer 27

Dissection lateral to trachea will cause injury to left recurrent laryngeal nerve and possibly disruption of the tracheal blood supply

Question 28

Where is incision made for tracheostomy

Answer 28

Between 3 & 4th or 5th tracheal rings

Question 29

What are possible complications of tracheal tube suctioning?

Answer 29

Anxiety, respiratory distress, vagal stimulation causing vomiting or retching

Question 30

What must be done before initiating tracheal tube suctioning?

Answer 30

Airway humidified and preoxygenate for at least 3 minutes

Question 31

When is thoracocentesis indicated?

Answer 31

When patient has fluid or air accumulation in pleural space believed to be causing or contributing to respiratory difficulties

Question 32

How is tracheostomy site closed?

Answer 32

It is not, left open and heals on own

Question 33

Where is thoracentesis performed if performed blindly?

Answer 33

7th - 9th intercostal spaces
If air suspected in middle to upper thorax
If fluid suspected in lower third of chest

Question 34

Where are the internal thoracic arteries located?

Answer 34

Along ventral thorax a few centimeters to either side of the sternum

Question 35

Where are the major vessels and nerves located in relation to the ribs?

Answer 35

Along the caudal end of the ribs

Question 36

How many days of continuous suction with continued air production might indicate it is time for thoracotomy?

Answer 36

2-5 days

Question 37

When should a thoracotomy tube be removed?

Answer 37

No air should be removed for 24 hours prior to tube removal
Fluid may continue to accumulate but no more than 2mL/kg/day
Imaging prior to pulling tube