Principles Ii Test 2

Front 1

PH

Back 1

= neg. log of H+. PH 5 = .00001 H+

Difference between PH 7 and PH 4 = 7-4 =3

10^3x more H+. (1000x)

Front 2

Bronsted-Lowry definitions of acid/base?

Back 2

Acid = proton donor

Base = proton acceptor

Front 3

Henderson-Hasselbach equation?

Back 3

PH=Pka + log (HCO3/0.03xPaCO2)

PH= 6.1 + log (24/0.03x40)

PH= 6.1 + log (24/1.2)

PH= 6.1 + log (20) = 7.4

Front 4

4 buffer systems:

Back 4

Bicarbonate, Hgb, IC Proteins, Phosphates

HCO3 = open system, 20x buffering capacity of closed/chemical systems

Front 5

How is HCO3 reabsorbed?

Back 5

by the kidneys, mechanism is Na+/H+ exchange (bicarb in tubule, joins with H+ (H2CO3), ca, H20 and CO2, pass tubule lumen into interstitium, reaction reverses, H+ go back to tubule, bicarb absorbed to bloodstream)

Front 6

Most important noncarbonic buffer EC?

Back 6

Hgb. Bicarb = 60% buffering, HHgb = 35%

plasma proteins = 5%

Histadine is the main buffer site of Hgb which represents a closed system

Front 7

What is the major IC buffer?

Back 7

IC proteins (slower process takes 2-4 hours)

Front 8

Most important urinary buffer?

Back 8

Phosphate system ( "P" most important in Pee)

H2PO4/HPO4

Front 9

Ratio of HCO3 to CO2 (or metabolic to respiratory)?

Back 9

20:1, 24/1.2 (think H/H equation)

PH = Metabolic/Respiratory

(Resp. faster response (minutes), Renal comp. most powerful but takes 12-48h, maximal in 5 days.)

Front 10

Acidosis effects?

Back 10

Cardiac/sm.muscle depression, less resp. to catecholamines, lower V. Fib threshold, Hyperkalemia, CNS depression, Cerebral vasodilation, augmentation of NDMR in resp. acidosis

Front 11

Causes of Resp. Acidosis?

Back 11

Hypoventilation OR increased CO2 production!

(MH, Sz, shivering, burns, thyroid storm)

Front 12

Can Respiratory compensation fully correct a metabolic disturbance?

Back 12

No, but metabolic compensation can fully correct a respiratory disturbance

Front 13

Formula for HCO3 administration?

Back 13

Only give if PH less than 7.2 or HCO3 less than 15

MEQ NaHCO3 = (kg wghtx0.3xBase deficit)/2

(1 amp of bicarb is 50mEq, so divide answer by 50 to get # of amps)

Front 14

Anion Gap?

Back 14

cations - anions

AG = Na+ - (Cl + HCO3), normal is 7-14

140-(104+24) = 12

High AG acidosis = greater than 30

MUDPILERS (Methanol,Uremia,DKA,Paraldehyde/Propofol, Iatrogenic/idiopathic,Lactic Acid, Ethylene Glycol/Ethanol, Rhabdo, Salicylates)

Front 15

Normal AG acidosis causes?

Back 15

GI losses of bicarb: Diarrhea, ileus, CaCl/MgCl, fistula drainage

Renal loss of bicarb: Renal tubular acidosis, ca inhibitors (Diamox)

Rapid ECF dilution with fluid lacking HCO3

Front 16

Effects of Alkalosis?

Back 16

Hypokalemia, Hypocalcemia (ionized), Left shift of OHDC, Vasoconstriction (SVR, Cerebral, CNS excitation/sz, coronary spasm), bronchoconstriction

Front 17

Most common acid/base disorder in ICU?

Back 17

Metabolic Alkalosis, from primary increase in plasma HCO3.

3 causes: chloride sensitive, chloride resistant, and massive blood transfusions (citrate metabolism)

Front 18

Chloride Sensitive Met. Alkalosis?

Back 18

Cl deficiency and ECF depletion of H+from:

1.GI losses (vomiting, GI drg., chloride diarrhea)

2. Renal (Diuretics, posthypercapnic, low Cl intake

3. Sweat (cystic fibrosis)

(ECF depletion causes Na+ resorption in kidneys, but not enough Cl to balance, so kidneys absorb more bicarb to maintain electroneutrality)

TX: IV Saline plus K+, H2 blockers

Front 19

Chloride Resistant Met. Alkalosis?

Back 19

INCREASED mineralocorticoid activity leads to H+ and K+ excretion, Na+ reabsorption. K+ depletion causes increased bicarb resorption in proximal and distal renal tubules

Cushings, hyperaldosteronism, Licorice injestion, Bartter's syndrome (JGA hypertrophy), severe hypokalemia

TX: IV hydrogen ions (HCL, ammonium chloride) or Diamox

Front 20

Ways to figure out dissolved O2 and CO2 in blood?

Back 20

Henry's law

O2: 0.003ml/dl/mmHg

CO2: 0.067ml/dl/mmHg OR 0.03mmol/L/mmHg at 37C (H/H equation)

Front 21

P50 of OHDC?

Back 21

P50 is the PaO2 at 50% saturation = 26.6mmHg or 27.

Sets the middle of the curve, increased P50 is a Right shift (takes more paO2 to hold 50% sat), decreased P50 is a left shift (O2 wants to stick to the Hgb, less PaO2 needed to achieve 50% sat)

Front 22

Causes of Left and Right shift of OHDC?

Back 22

Left: hypothermia, hypocarbia, alkalosis, decreased 2,3 DPG, CO, Methgb, Carboxyhemoglobinemia

Right: hyperthermia, hypercarbia, acidosis, increased 2,3 DPG, Pregnancy

Front 23

Bohr Effect vs. Haldane effect?

Back 23

B"o"hr = What O2 curve does in response to CO2 levels (lungs: low CO2, O2 curve shifts left to load. Periphery: high CO2, O2 curve shifts right to release)

Haldane = What CO2 curve does in response to O2 levels (lungs: high O2, CO2 curve shifts down and right (darn right) to release. Tissues: low O2, CO2 curve shifts up and left to load)

Front 24

What three forms is CO2 transported in?

Back 24

HCO3: 68%

Carbaminohemoglobin: 22%

Dissolved in plasma: 10%

Front 25

Chloride (Hamburger) shift?

Back 25

Chloride shifts from plasma to RBC and back to maintain electroneutrality. Chloride goes for the ride!

Tissues: CO2 to RBC, converted to bicarb. Bicarb diffuses to plasma. Cl shifts from plasma to RBC.

Lungs: Cl moves out of RBC. HCO3 reenters RBC and converts back to CO2. CO2 diffuses into alveoli.

Front 26

CO2 change in apnea? PH change in CO2 change? K+ change in PH change?

Back 26

CO2 increases 5-6mmHg in 1st minute of apnea and 3-4mmHg each min. thereafter (3456)

PCO2 change of 10mmHg = 0.08 change in PH

K+ conc. changes 0.6 mEq/L per 0.1 change in arterial PH (PH up K down, PH down K up)

Front 27

Respiration (gas exchange) starts at the

Back 27

Respiratory bronchioles.

Resp. bronchioles + alveolar ducts = transitional zone

Alveolar sacs = respiratory zone

Front 28

Distance from mouth to cords? Mouth to carina? Length of ETT?

Back 28

mouth to cords: 16-19cm

mouth to carina: 24-29cm

length of whole ETT: 29cm

mid trachea: 21-22cm

Front 29

How does the bronchial tree get blood supply?

Back 29

Trachea to pulmonary (Terminal?) bronchioles = bronchial circulation (2% of LV output)

Distal to terminal bronchioles (respiratory bronchioles, alveolar ducts/sacs) = total RV output

Front 30

How much blood in the lungs at a given time?

Back 30

450ml, 13% of CO. 70-100ml undergoing gas exchange.

Front 31

What are the major respiratory centers and where are they located?

Back 31

Dorsal resp. group: medulla, inspiration, pacemaker, phrenic n. to diaphragm, efferent to external intercostals

Ventral resp. group: medulla, expiration, not active during normal breathing (overdrive), efferent to internal intercostals

Pneumotaxic center: Pons, stops inspiration

Apneustic center: Pons, insp. gasps, apneuses

Front 32

Central and peripheral chemoreceptor differences?

Back 32

Central: sensitive to PCO2, NOT PO2! PaCO2 indirect stim., H+ direct stim./changes CSF PH

Peripheral: sensitive to both PCO2 and PO2, but response to PO2 is stronger (less than 60mmHg)

Response is faster than central chemoreceptors, more important for short term response.

Front 33

Where are the peripheral chemoreceptors, which has a stronger influence, and what nerves carry their afferent signals?

Back 33

Carotid Bodies: more influence than aortic. Hering's nerve (Glossopharyngeal IX) is its afferent pathway to DRG

Aortic Bodies: above and below aortic arch, less influence, Vagus X is its afferent pathway to DRG

Front 34

What are the muscles of inspiration/expiration?

Back 34

Inspiration: DESS: Diaphragm, External intercostals, Scalenes, Sternocleidomastoids

Inspiration is active.

Expiration: RIO-EO-I: (most important are of abdominal wall) Rectus abdominus, Internal Obliques, External Obliques, and Internal intercostals. Expiration is normally passive.

Front 35

How do intrapleural and intrapulmonary pressures change with breathing?

Back 35

Intrapulmonary (alveolar) pressure: Negative inspiration, positive expiration, ZERO at end inspiration/expiration

Intrapleural pressure: ALWAYS negative during normal breathing. Pressure varies from -5 to -10 cm H20, more negative on inspiration, less negative on expiration. Valsalva maneuver can make it positive.

Front 36

Law of Laplace

Back 36

T=PR for cylinder or T= (PR)/2 for sphere.

Describes why small spheres (alveoli) empty into larger ones. Surfactant (dipalmitoyl lecithin) reduces surface tension, which evens the pressure between small and large alveoli preventing collapse. surfactant from TYPE II alveolar cells.

Front 37

Formula for partial pressure of inspired O2 and alveolar air equation?

Back 37

PiO2 = (Pb-PH20)xFiO2 = (760-47)x.21 = 149.3

PAO2 = (Pb-PH20)xFiO2 - PaCO2/RQ

149.3 - 40/0.8 = 99.3mmHg

PAO2 shortcut rule of 6, take FiO2 x 6 (50% x 6 =300)

Front 38

Formula for normal PaO2?

Back 38

102-(age/3)

75y.o. = 102-(75/3) = 102-25 = 77mmHg

Front 39

Formula for normal A-a gradient at .21% O2?

Back 39

Age/4 + 4

70y.o.: 70/4 = 17.5+4 = 21.5mmHg

Normal A-a gradient 2-22, increases with age and FiO2

Front 40

arterial oxygen content equation?

Back 40

CaO2= 1.34xHgbxSaO2 + 0.003xPaO2

CaO2= 1.34x15x1.0 + 0.003x100mmHg

CaO2= 22.5 mlO2/dl

SHORT CUT = 1/2 HCT

Front 41

Normal CvO2, DO2, VO2?

Back 41

CvO2: 15 mlO2/dl

DO2: 1000 ml/min (CaO2 x CO)

VO2: 250 ml/min = (CaO2-CvO2)xCO

Front 42

Resistance equals

Back 42

change in pressure/flow

SVR=Map-Cvp/CO

R=P/Q

Front 43

Lung volumes and their size?

Back 43

Inspiratory Reserve Volume: 3000ml

Tidal Volume: 500ml

Expiratory reserve volume: 1100ml

Residual volume: 1200ml

Front 44

Lung capacities and their size?

Back 44

Vital capacity: IRV+TV+ERV: 4600ml

Inspiratory capacity: TV+IRV: 3500ml

Functional residual capacity: ERV+RV: 2300ml

Total lung capacity: all volumes: 5800ml

Closing capacity: closing volume + RV, usu. below FRC, but increases with age and by 66yo CC equals or exceeds FRC

Front 45

Hypoxic pulmonary vasoconstriction results from

Back 45

ALVEOLAR hypoxia, reduces shunt, and is disabled by: above 1 MAC volatiles, hypocarbia, vasodilators (ntg, nipride, CCB), and nitric oxide

Front 46

General anesthesia decreases FRC by how much?

Back 46

15-20%

also contributes to venous admixture by 5-10%

Supine position decreases FRC by 10%

So GA in supine position FRC decreased 30%

Front 47

FEV1/FVC ratio levels of obstruction?

Back 47

75% or greater: no obstruction/normal

60-70%: mild obstruction

50-60%: moderate obstruction

less than 50%: severe obstruction

Normal in restrictive disorders!

Front 48

Lung volumes that increase in obstructive disorders?

Back 48

RV, FRC, TLC (all the ones that we can't measure directly) VC, IRV, ERV decrease

restrictive: all decrease

Front 49

Dead Space

Back 49

Anatomic dead space: never changes (conducting airways)

Alveolar dead space: varies, alveoli without perfusion

Physiologic DS: Anatomic + Alveolar DS

Normal Anatomic DS: 2ml/kg or 150ml

Front 50

A-a gradient due to?

Back 50

Bronchial circulation and thebesian circulation that contribute to normal physiologic shunt and empty deoxygenated blood directly to pulm. arteries and LV.

Front 51

Normal V/Q ratio?

Back 51

Overall: 4L ventilation/ 5L CO = 0.8

Individual lung units: Varies.

increased V/Q ratio = DS, increased PO2, Decreased PCO2

Decreased V/Q ratio = Shunt, decreased PO2, increased PCO2

Front 52

Where does the respiratory quotient come from?

Back 52

CO2 out/ O2 in

VCO2/VO2

200ml/min / 250ml/min

Normal: 0.8

Front 53

What are the West lung zones?

Back 53

Describe relationship between alveolar, pulmonary arterial, and pulmonary venous pressures.

Zone I: PA>Pa>Pv (not normally present)

Zone II: Pa>PA>Pv (waterfall effect)

Zone III: Pa>Pv>PA (continuous capillary flow)

Want Swan in zone III

Front 54

Where is ventilation and perfusion better?

Back 54

The dependent lung, unless lateral position and paralyzed/anesthetized. In this case upper lung is better ventilated but not perfused (dead space) while the lower lung is poorly ventilated but perfused well (shunt) creating a V/Q mismatch

Front 55

Main site of airway resistance?

Back 55

Central airways (90%)

Front 56

Greatest decrease in VO2 due to GA are by which two areas?

Back 56

Cerebral and Cardiac oxygen consumption

Front 57

Osmolality of ECF? ICF?

Back 57

ECF: 290mosm/L

ICF: 310mosm/L

Front 58

Plasma volume expansion equals:

Back 58

PV/Vd

Colloids: 3/3= 1:1 (100%)

Isotonic Crystalloids: 3/14 = 1:5 (20%)

Hypotonic Cryst: 3/42 = 1:14 (7%)

Front 59

First sign of Hypermagnesemia?

Back 59

Loss of deep tendon reflex

Hyporeflexia

Front 60

Cause of Hypophosphatemia?

Back 60

Respiratory alkalosis, hyperparathyroid, hypercalcemia, alcoholism

Front 61

How long do crystalloids last intravascularly?

Back 61

20-30minutes

Front 62

What cervical level is the larynx, hyoid, epiglottis, cords, thyroid, and cricoid cartilages?

Back 62

larynx: C3-C6

hyoid: C3

epiglottis: C3 (C3-PO says "Hi" without epiglottis)

cords: C5

thyroid: C4-5

cricoid: C6

Front 63

What are the muscles of the larynx and their function?

Back 63

"Post LOTS of Crazy Things"

Posterior Cricoarytenoids (PCA) pulls cords apart, abducts the cords

Lateral Cricoarytenoids plus oblique and transverse arytenoids adduct cords (lots of stuff)

Cricothyroids (CCT = Cords can tug) tenses/elongates cords

Thyroarytenoids relax cords, shorten cords

Front 64

What are the extrinsic muscles of the tongue?

Back 64

"Mario's Pal Geno Has Style"

Palatoglossus, Genioglossus, Hyoglossus, Styloglossus

All intrinsic and extrinsic muscles of tongue are supplied by Hypoglossal (CN XII) except for palatoglossus supplied by CN X.

Taste of anterior 2/3 of tongue from Facial CN VII carried by lingual nerve. (taste and sensory posterior 1/3 = Glossopharyngeal CN IX)

Front 65

Definition of Difficult Airway

Back 65

situation where trained anesthesia professional experiences difficulty with mask ventilation, tracheal intubation or both