Basic - Physiology Flashcards

1
Q

Why doesn’t discontinuation of N2O improvement in hemodynamic stability in pts with CO2 embolism?

A

CO2 is MORE soluble than N2O
- CO2 will move out or be absorbed/buffered more quickly than N2O

*note, you should still turn it off and turn on 100% O2

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2
Q

Does ETCO2 increase or decrease with CO2 embolism?

A

Both

  • Increase: 2/2 to vascular CO2 insufflation
  • Decrease: 2/2 to hemodynamic instability
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3
Q

What is the purpose of preoxygenation prior to induction?

A

After passive exhalation, the remaining volume is the FRC.

  • Goal is to increase FRC FiO2
  • removing nitrogen from FRC increases O2 content available for apneic oxygenation (inc reserves)
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4
Q

Why is arterial oxygen content not affected by changes in PaO2?

A

It is more affected from hgb [ ] and oxyhemoglobin saturation of oxygen

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5
Q

The STATIC compliance of the respiratory system indicates what? When is it determined?

A

The “stiffness”

  • lungs
  • chest wall

At the end of inspiration when there is NO airflow, hence, “static”
- Plateau Pressure*

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6
Q

The DYNAMIC compliance of the respiratory system indicates what? When is it determined?

A

The “resistance”

Can be measured at any point during inspiration when there is airflow
- Peak Pressure *

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7
Q

______ is the inverse of compliance of the respiratory system

A

Elastance

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8
Q

What hormones are INCREASED during stress response?

A

Pituitary: GH, ACTH, Prolactin, AVP
Effect organs: cortisol, aldosterone, glucagon

*TSH, LH, FSH unchanged

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9
Q

The end product of (anaerobic / aerobic) metabolism are CO2 and water

A

anaerobic

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10
Q

(anaerobic / aerobic) metabolism utilizes glucose as the starting substrate

A

Both
- start with same initial reaction that convert glucose -> 2 pyruvate

aerobic metab: makes 30-36 ATP
Anaerobic: 2-4 ATP? (a lot less)

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11
Q

Vasopressin is also known as?

A

ADH

AVP (arginine vasopressin)

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12
Q

Where are V1 and V2 receptors located?

A

V1: vascular smooth muscle
V2: distal and collecting tubules

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13
Q

How is FRC affected by :
Height
Advanced age

A

Increased in both (nl is 3-4L)

Height
Advanced age
- loss of elastic lung tissue, lessens contractile force of lung -> moves balancing point to a higher lung volume

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14
Q

Causes of LOWered FRC

A

PANGOS

Pregnancy
Ascites
Neonatal
GA
Obesity
Supine pos
\_\_\_\_\_\_
decrease height
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15
Q

SYmpathetic cardiac innervation originates from ______.

Target receptor sites for sympathetic cardiac innervation are ____

A

T1-T4

a1, b1, b2

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16
Q

The closing of the mitral valve corresponds with which wave on the EKG?

A

R wave

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17
Q

The (Sympathetic / Parasympathetic) nervous system is the dominant nervous system involved in BRONCHOCONSTRICTION and inc mucus production

A

Parasympathetic

*norepi, which stim sympathetic nervous system is a potent bronchial sm dilator

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18
Q

How is LV contractility affected by sodium bicarb administration?

A

HCO3- Binds calcium -> Serum i-cal [ ] transiently decreases -> less contractility in LV

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19
Q

How is lactate production affected by sodium bicarb administration?

A

Acutely correct acidotic pH (raise it) -> INCREASE hgb affinity for O2 -> worsens hypoxia ->
Increase lactate production

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20
Q

How is hgb affinity for O2 affected by sodium bicarb administration?

A

INCREASES

- higher pH, shifts curve to LEFT

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21
Q

What hormones are activated in the lungs?

A

Angiotensin I

Arachidonic acid

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22
Q

What hormones are INactivated in the lungs?

A
  1. Adenosine
  2. ATP/ADP/AMP
  3. Bradykinin
  4. Endothelins
  5. Leukotrienes
  6. Norepi*
  7. PDG2, PGE2, PGF2
  8. Serotonin*

*everything else is unchanged

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23
Q

Carcinoid triad

A

Flushing
Diarrhea
R sided HF

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24
Q

Uosm : Posm _____ indicates prerenal oliguria

A

> 1.5

*normal plasma osm is 280-300

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25
Q

What does glucagon stimulate?

A

Glycogenolysis
Gluconeogenesis
Lipolysis

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26
Q

Total body water (60% body weight, 42L) is divided into _____ and _____

A

intracellular volume
- 2/3, 40% TBW

extracellular volume

  • 1/3, 20% TBW
  • interstitial fluid 75% of EVC
  • plasma is 25% of ECV
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27
Q

The MAC-BAR is the value that blunts adrenergic responses to noxious sitm is ___% higher than std MAC

A

50%

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28
Q

The MAC-awake ist he MAC where voluntary reflexes (ie. no longer open eyes to command, shouting or shaking) is ____% of std MAC

A

15-50%

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29
Q

Common signs of hypoglycemia

A

*Inc in sympathetic dischrge, cortisol and glucagon release

Diaphoresis
Tachycardia
HTN
AMS
Sz

*If a pt is taking a BB, you may not see tachycardia or HTN

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30
Q

What is the haldane effect?

A

Inc ability of hgb to carry carbon dioxide from the tissues to the LUNGS for exhalation

  • in low O2 [ ], hgb binds more strongly to CO2
  • in high O2 [ ], CO2 dissociates from hgb, and inc PCO2
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31
Q

The _____ effect explains inc binding of CO2 for delivery to the lungs, the _____ effect explains decreased binding of O2 for delivery to the tissue

A

Haldane

Bohr

32
Q

The _____ chemoreceptors increase ventilation when PaO2 (not PAO2 or SaO2) decreases through afferent impulses via the GLOSSOPHARYNGEAL nerve to CNS ventilation centers.

A

Carotid body

33
Q

How sensitive are Carotid body chemoreceptors to anesthetic drugs (opioids, BDZ, volatile anes 0.1 MAC)?

A

Very sensitive

- can cause respiratory insufficiency

34
Q

Similarities and Difference btwn Carotid Bodies and Carotid SInuses?

A

Both are located at carotid bifurcation and impulses are transmitted via branch of GLOSSOPHARYNGEAL N (Hering’s n.)

Carotid bodies are chemoreceptors
Carotid sinuses are baroreceptors

35
Q

Bronchoconstriction is d/t (sympathetic / parasympathetic) stimulation that occurs through the ____ n.

A

parasympathetic

VAGUS n.

36
Q

How do alpha and beta receptors affect bronchial airways?

A

alpha - bronchoconstriction

beta - bronchodilation

37
Q

Synthetic liver fxn is best assessed via PT/INR which most closely correlates with factor ___ levels, which has a half life of ___ hours

A

VIIa (half life of 4 hours)

38
Q

Increases in direct or unconjugated bilirubin is a sign of ____

A

disruption in bile removal
- ie. choledocolithiasis

Liver still has ability to convert unconjugated to conjugated bilirubin

39
Q

Carotid body CHEMOreceptors are primarily responsive to ______

A

reductions in arterial partial pressure of oxygen (PaO2)
- ~ < 60 mmHg

*NOT affected by arterial oxygen sat (SaO2), arterial oxygen content (CaO2)

40
Q

CO poisoning results in ____ shift in the oxygen-hemoglobin dissociation curve.

A

LEFT

41
Q

Does increasing Hgb increase oxygen delivery?

A

Yes, it increases arterial oxygen content ->
increased oxygen delivery

Eq for Oxygen delivery (DO2) = CO x CaO2

*CaO2 is arterial oxygen content

42
Q

Btwn the Child-Pugh score and MELD score, they both use:
bilirubin
INR
- how do they differ?

A

Child Pugh

  • Synthetic fxn of liver (Albumin, PT)
  • Presence of ascites or encephalopathy

MELD

  • Creatinine
  • more accurate predictor of short term mortality
43
Q

How do these affect the oxygen-hgb oxygen curve?

  • Methemoglobinemia
  • CO poisoning
  • HYPOphosphatemia (substrate for production of 2,3 DPG)
A

LEFT shift

  • decreased oxygen delivery to tissue
  • increased affinity for oxygen
44
Q

What is the P50?

A

partial pressure of oxygen at which hgb is 50% saturated

- nl P50 is 27 mmHg

45
Q

When does hypophosphatemia usually occur?

A
Secondary to sepsis
malnutrition
refeeding syndrome
acute liver injury
DKA

*left shift in hgb-diss curve

46
Q

Hypercapnia following admin of O2 to a pt with COPD is primary d/t ____

A

V/Q mismatch (perfusion to alveoli with zero or low ventilation)
- driven by inhibition of hypoxic pulmonary vasoconstriction by high oxygen tensions in under-ventilated lung units

47
Q

Why do we titrate saturations in Pts with COPD to 88-92%?

A

Hypoxic pulmonary vasoconstriction is the most efficient way to alter V/Q ratios to improve gas exchange

Too much O2 = oxygen induced hypercapnia (haldane effect)

48
Q

What is the mixed venous oxygen saturation (SvO2)?

A

The percentage of oxygen bound to hgb in the blood returning to the R side of the heart (oxygen “left over” after body has extracted what it needs)

  • data from pulmonary a. catheter (all the venous blood returning from the SVC, IVC, and coronary sinus)
  • nl = 75%
49
Q

When is mixed venous oxygen saturation (SvO2) DECREASED?

*(SvO2 = oxygen “left over” after body has extracted what it needs)

A
  1. Inc. oxygen consumption (hyperthermia, shivering, pain)
  2. Dec. Cardiac output (MI, hypovolemia)
  3. Dec. Hgb [ ]
  4. Dec. arterial oxygen sat (SaO2)
50
Q

When is mixed venous oxygen saturation (SvO2) INCREASED?

*(SvO2 = oxygen “left over” after body has extracted what it needs)

A
  1. Inc hgb [ ] (blood transfusions)
  2. Inc arterial oxygen sat (SaO2)
  3. Dec total body O2 consumption (VO2) (cyanide tox, sepsis, CO poisoning, methemoglobinemia, hypothermia)
  4. Inc Cardiac output (sepsis)

*Body may be unable to extract oxygen

51
Q

How does Norepi affect bronchial smooth muscle?

A

No sig change

- More selective for B1 > B2 (bronchial sm relaxation)

52
Q

How does Muscarinic 3 stimulation affect bronchial smooth muscle?

A

Bronchial sm contraction

53
Q

What is lusitropy? How does it affect the LV pressure-vol loop?

A

Myocardial relaxation

- downward shift in LV pressure-vol loop

54
Q

How is chest wall compliance different in neonates compared to adults? Cons?

A

Chest wall compliance is higher (more pliable rib cage)

- Increases WOB since rib case provides less mechanical support

55
Q

Hydromorphone metabolism and excretion?

A

Metabolism in liver via phase 2 glucuronidation –> hydromorphone-3-glucuronide –> renally excreted

  • hydromorphone-3-glucuronide accumulates in CKD
  • no analgesia
  • neurotoxic
56
Q

Morphine metabolism and excretion?

A

Metabolism in liver via phase 2 glucuronidation -> Morphine-3-glucuronide and Morphine-6-glucuronide –>
Both renally excreted

  • Both can accumulate in pts with CKD
  • M6G has analgesic properties, no neuro excitability (resp depression)
  • M3G has neuroexcitability
57
Q

Which requires a higher [ ] of anesthetic to prevent MAC50, direct laryngoscopy or ET intubation??

A

ET intubation

58
Q

How does alpha 2 and beta 2 stim affect lipolysis?

A

alpha 2: Inhibit lipolysis

beta 2: stim lipolysis

  • stress response = catecholamine inc lipolysis -> loss of fat and lean body mass
59
Q

Why does rapid admin of normal saline cause a non-anon gap hyperchloremic metabolic acidosis?

A

Na+ and Cl- are both strong ions

  • strong ion difference of 0 = no anion gap
  • nl human plasma SID = 40, if you give rapid admin, you bring SID closer to 0 -> acidemia
60
Q

The ____ equation is used in ECHOs to assess pressure gradient and area of mitral and aortic valves

A

Bernoulli’s equation

61
Q

The _____ equation is used to calculate oxygen consumption. Gold std by which Cardiac output is calculated

A

Fick principle

62
Q

________ equation is used to describe a chemical system at equilibrium (ie. bicarb and CO2 eq)

A

Le Chatelier’s principle

63
Q

Depolarization causes an influx of ____.

The first and second step of action potential termination:

A

influx of Na+
_____________
1) Na channel inactivation
2) efflux of K+

64
Q

How do LA work?

A

Reversibly binding VG Na channels

- prevent depolarization (influx of Na+)

65
Q

How does the botulinum toxin work?

A

Prevent membrane fusion and release of ACh into the synaptic cleft

66
Q

How does tetrodotoxin (puffer fish poison) work?

A

Inhibits VG fast sodium currents in myocytes

- inhibits Action potential propagation

67
Q

How does Ciguatoxin (Reef fish poison) work?

A

Opens Na+ channels -> depolarization

68
Q

How is CO2 primarily transported in blood?

A
  1. Dissolved CO2
  2. Bicarb
  3. Carbamino compounds (rxns with proteins)
69
Q

Largest contributor to initial reduction in core temp during GA?

A

Redistribution of heat from core to periphery
- redistribution hypothermia

Second is Radiative heat loss to surroundings

70
Q

How does stored pRBCs affect the hgb-dissoc curve?

A
LEFT shift (inc hgb affinity for O2, lower P50)
- has less 2,3-DPG
71
Q

Things that increase 2,3 DPG

RIght shift - decrease hgb affinity for O2

A
  1. HYPERphosphatemia
  2. HYPERthyroidism
  3. Anemia
  4. Liver cirrhosis
  5. Sleep apnea
  6. HF
  7. High altitude hypoxia
72
Q

Mneumonic for R ward shift in oxy-hgb dissoc curve.

*(RIght shift - decrease hgb affinity for O2)

A
CADET Face Right
Inc in:
CO2
Acid
2,3 DPG
Exercise
Temp
73
Q

How does HYPERnatremia affect MAC?

A

Increases

74
Q

Why doesnt adding to the inspiratory or expiratory limb add dead space?

A

Limbs are one way, no gas mixing

75
Q

Mneumonic to remember the amt of rebreathing in Mapleson circuits
Rebreathing during SPONTANEOUS ventilation:
Rebreathing during CONTROLLED ventilation:

A

Rebreathing during SPONTANEOUS ventilation: A > D > C > B
- All Dogs Can Breathe

Rebreathing during CONTROLLED ventilation: D > B > C > A
- Dead Bodies Can’t Assist

76
Q

Fetal hgb shifts curve to the (Right / Left)

A

Left (inc hgb affinity for O2, lower P50)

- improves O2 delivery to the fetus from the placenta

77
Q

Insulin has (catabolic/anabolic) effects

A
anabolic (builds up)
stimulates uptake / storage of:
- glucose
- amino acids
- fatty acids  
it also INHIBITS catabolic processes below:
- lipolysis
- protein breakdown
- ketone formation
- oxidation of FA and AA
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
- glycogenolysis
- gluconeogenesis