Respiratory, pulmonary and ABG physiology

Question 1

Is the volume in the lungs at the end of passive

expiration

Answer 1

Functional residual capacity (FRC)

Question 2

Normal FRC

Answer 2

1.7 to 3.5 L

Question 3

FRC is increased by (3)

Answer 3

1) Body size
2) Age
3) Lung diseases (asthma & COPD)

Question 4

FRC is decreased by (5)

Answer 4

1) Sex (decreased in females)
2) Paralyzed diaphragms
3) Posture (greatest standing, lowest supine)
4) Lung disease with less elastic recoil
5) Inc abdominal pressure

Question 5

At low flow, or laminar flow (nonobstructed breathing), The _____ is the major property of the gas that affects flow.

Clearly the major determining factor is the ____ of the
tube.

Answer 5

Viscosity

Radius

Question 6

At higher flow rate (in obstructed airways and heavy breathing), turbulent flow, the major determinants of resistance to flow are the ______ and _____.

Answer 6

Density of the gas

Radius of the tube

Question 7

What equation describes the relationship between pressure, FLUIDIC resistance and flow rate?

Answer 7

Hagen–Poiseuille

Question 8

This law essentially states that the TENSION within the wall of a sphere filled to a particular pressure depends on the thickness of the sphere.

Answer 8

Laplace’s law

Question 9

normal A-a gradient is estimated as follows:

Answer 9

A-a gradient = (age/4) + 4

Question 10

Under general anesthesia FRC is reduced by approximately ____ ml in an adult.

The supine position decreases FRC another ___ ml

Answer 10

400 mL

800 mL

Question 11

Is the sum of anatomic and alveolar dead space.

Answer 11

Physiologic dead space

Question 12

Is the space is the volume of lung that does not exchange gas.

Answer 12

Anatomic dead space

Question 13

Examples of anatomic dead space (4)

Answer 13

1) nose
2) pharynx
3) trachea
4) bronchi

Question 14

How much is the anatomic dead space (mL/kg)?

Answer 14

2 mL/kg

Question 15

This space is the volume of gas that reaches the alveoli but does not take part in gas exchange because the alveoli are not perfused.

Answer 15

Alveolar dead space

Question 16

What is defined as blood that reaches the arterial system without passing through ventilated regions of the lung?

Answer 16

Absolute shunt

Question 17

How many percent of cardiac output is normally shunted through postpulmonary shunts?

Answer 17

2% to 5%

Question 18

Examples of postpulmonary shunts?

Answer 18

1) thebesian
2) bronchial
3) mediastinal
4) pleural veins

Question 19

Is a local response of pulmonary arterial smooth muscle that decreases blood flow in the presence of low alveolar oxygen pressure?

Answer 19

Hypoxic pulmonary vasoconstriction (HPV)

Question 20

What inhibits HPV?

Answer 20

HPV is inhibited by volatile anesthetics and vasodilators but is not affected by intravenous anesthesia.

Question 21

What is the O2 content per gram hemoglobin?

Answer 21

1.34

Question 22

CO2 exists in three forms in blood (3)

Answer 22

1) Dissolved CO2 (7%)
2) Bicarbonate ions (HCO3) (70%)
3) Combined with hemoglobin (23%)

Question 23

What respiratory center is mainly responsible for inspiration?

Answer 23

Dorsal respiratory center

Question 24

What respiratory center is responsible for both expiration and inspiration?

Answer 24

Ventral respiratory center

Question 25

What respiratory center helps control the breathing rate and pattern?

Answer 25

Pneumotaxic center

Question 26

Where is the dorsal respiratory center located?

Answer 26

It is located within the nucleus solitarius where vagal and glossopharyngeal nerve fibers terminate.

Question 27

Most common iatrogenic cause of hypercarbia?

Answer 27

NaHCO3 administration

Question 28

Elevated anion gap metabolic acidosis is caused by accumulation of unmeasured anions. What are the causes of elevated anion gap? (4)

Answer 28

1) Lactic acid 2) Ketones 3) Toxins (ethanol, methanol, salicylates, ethylene glycol, propylene glycol) 4) Uremia

Question 29

What buffer is the fastest to respond to pH change but has less total capacity than the intracelluar systems, this accounts for 60-70% of chemical buffers?

Answer 29

Extracellular bicarbonate system

Question 30

Primary organ involved in rapid acid-base regulation

Answer 30

Lungs

Question 31

What organs play a major role in acid-base balance?

Answer 31

1) Lungs 2) Kidneys 3) Liver 4) GIT

Question 32

Severe acidemia is defined as blood pH of?

Answer 32

< 7.20

Question 33

Is the amount of base (or acid) needed to titrate a serum pH back to normal at 37 C while the PaCO2 is held constant at 40 mm Hg.

Answer 33

Base deficit (or base excess)

Question 34

Estimates the presence of unmeasured anions.

Answer 34

Anion gap (AG)

Question 35

Normal value of anion gap?

Answer 35

12 mEq/L +- 4 mEq/L

Question 36

What metabolic acidosis results from loss of Na and K or accumulation of Cl. Theresult of these processes is a decrease in HCO3?

Answer 36

Nonanion gap metabolic acidosis

Question 37

(Nonelevated) Nonanion gap metabolic acidosis causes (5)

Answer 37

1) Iatrogenic administration of hyperchloremic solutions (hyperchloremic metabolic acidosis) (excess administration of normal saline) 2) Alkaline gastrointestinal losses 3) Renal tubular acidosis 4) Ureteric diversion through ileal conduit 5) Endocrine abnormalities

Question 38

Elevated AG metabolic acidosis causes (3)

Answer 38

1) lactic acid or ketones 2) poisoning from toxins (e.g., ethanol, methanol, salicylatesethylene glycol, propylene glycol) 3) uremia