First Aid 605-609 - Resp

Question 1

Formula to find O2 content of blood?

Answer 1

(1.34 × Hb × Sao2) + (0.003 × Pao2)

Question 2

How does O2 sat and PaO2 change with dec Hgb?

Answer 2

There is no change in either one, the only change is with dec O2 content in arterial blood (PAO2)

Question 3

What disease cause an increase in total O2 content?

Answer 3

Polycythemia

Question 4

In which disease will there be dec O2 sat’n but normal Hgb?

Answer 4

CO poisoning

Question 5

Treatment for CO poisoning?

Answer 5

100% O2, Hyperbaric O2

Question 6

Diffusion equation

Answer 6

Diffusion: V˙ gas = A × Dk × [(P1 – P2)/T]

A = area, T = alveolar wall thickness,
Dk(P1 – P2) ≈ difference in partial pressures:

Question 7

When is area decreased? when is alveolar wall thickness inc?

Answer 7

Emphysema, Pulm fibrosis

Question 8

Dec in pAO2 causes what in lung a/v?

Answer 8

VC (diff from systemic circ)

Question 9

PVR formula (pulm vas resistance)

Answer 9

PVR =( Ppulm artery – P L atrium)/CO

Question 10

When is A-a gradient normal / Inc?

Answer 10

Normal A-a gradient = 10-15 nmHg
A-a gradient may occur in hypoxemia; causes
include shunting, V˙/Q˙ mismatch, fibrosis
(impairs diffusion)

Question 11

Causes of Hypoxia

Answer 11

DEC cardiac output
Hypoxemia
Anemia
CO poisoning

Question 12

Causes of Hypoxemia (DEC PaO2)

Answer 12

Normal A-a gradient
ƒƒHigh altitude
ƒƒHypoventilation (eg, opioid use)
 
INCA-a gradient
ƒ ƒ V˙/Q˙ mismatch
ƒƒDiffusion limitation (eg, fibrosis)
ƒƒ Right-to-left shunt

Question 13

Ischemia (loss of blood flow)

Answer 13

Impeded arterial flow

 venous drainage

Question 14

T or F Both ventilation and perfusion are greater at the

base of the lung than at the apex of the lung.

Answer 14

True

Question 15

How does ventilation and perfusion change with exercise?

Answer 15

With exercise (INC cardiac output), there is
vasodilation of apical capillaries –> Ž V˙/Q˙ ratio
approaches 1.

Question 16

CO2 is transported from tissues to lungs in what forms?

Answer 16

HCO3− (90%).

ƒƒ Carbaminohemoglobin or HbCO2 (5%).
CO2 bound to Hb at N-terminus of globin
(not heme). CO2 binding favors taut form
(O2 unloaded).
ƒƒ
Dissolved CO2 (5%).

Question 17

Haldane effect explain?

Answer 17

In lungs, oxygenation of Hb promotes dissociation of H+ from Hb. This shifts equilibrium toward CO2 formation; therefore, CO2 is released from RBCs

Question 18

Bohr effect explain?

Answer 18

In peripheral tissue,  H+ from tissue

metabolism shifts curve to right, unloading O2

Question 19

Body response to high altitude - what metabolic disturbance

Answer 19

 atmospheric oxygen DEC (PO2) –> decŽ  Pao2 –> INC Ž  ventilation Ž  Paco2 Ž respiratory alkalosis –> Ž altitude
sickness.

Question 20

Other body responses to high altitude
What two things do we produce more of?
What happens in the kidney?
on a cellular level?

Answer 20

 Inc erythropoietin –> IncŽ  hematocrit and Hb (chronic hypoxia).

Inc  2,3-BPG (binds to Hb so that Hb releases more O2).

Cellular changes ( Inc mitochondria).

renal excretion of HCO3− to compensate for respiratory alkalosis (can augment with acetazolamide).

Question 21

What happens to pH in exercise?

Answer 21

Dec due to lactic acid

Question 22

How do gas values change in exercise? (PaO2, PaCO2, v CO2/o2 content)

Answer 22

No change in paO2, and PaCO2, but INC venous CO2, and dec venous O2

Question 23

Most common cause of rhinosinusitis?

Answer 23

Most common acute cause is viral URI; may cause superimposed bacterial infection, most
commonly S pneumoniae, H influenzae, M catarrhalis.

Question 24

Most common location of epistaxis? when is it dangerous?

Answer 24

Most commonly occurs in anterior segment of nostril (Kiesselbach plexus). Lifethreatening
hemorrhages occur in posterior segment (sphenopalatine artery, a branch of maxillary
artery).

Question 25

Most common type of cancer in head and neck?

Answer 25

Mostly squamous cell carcinoma

Question 26

Risk factors of Head and neck sq cell CA?

Answer 26

Risk factors include tobacco, alcohol, HPV-16 (oropharyngeal), EBV (nasopharyngeal)

Question 27

DVT Virchow’s triad?

Answer 27

*ƒ Stasis (eg, post-op, long drive/flight)
*ƒƒHypercoagulability (eg, defect in
coagulation cascade proteins, such as
factor V Leiden)
*ƒƒ Endothelial damage (exposed collagen
triggers clotting cascade)

Question 28

What makes the d-dimer test a good test to rule out DVT?

Answer 28

High sensitivity, low specificity

Question 29

Homan sign—? What is it, which disease?

Answer 29

dorsiflexion of foot –>Ž calf pain. in DVT

Question 30

Tx for DVT works on which intermediate of the clotting cascade? (Factor?) How are they administered?

Answer 30

Heparin, or LMWH work on Factor II. Heparin is IV, and LMWH can be given subcut.

Question 31

Imaging test of choice with DVT?

Answer 31

US

Question 32

interdigitating areas of pink (platelets, fibrin) and red (RBCs) found only in thrombi formed before death

Answer 32

Lines of Zahn - help distinguish

pre- and postmortem thrombi

Question 33

classic triad of hypoxemia, neurologic abnormalities, petechial rash. assoc with long bone fractures?

Answer 33

Fat embolli

Question 34

What metabolic disturbances with PE?

Answer 34

V˙/Q˙ mismatch –> Ž hypoxemia –> Ž respiratory alkalosis