Formulas Flashcards
(151 cards)
1
Q
maximum allowable blood loss
A
(EBV x (Hct starting- Hct target))/ Hct starting
2
Q
Law of Laplace
A
pressure= (2 x tension) / radius
3
Q
PVR
A
((mPAP-PAOP)/CO) x 80
Norm= 150-200
4
Q
SVR
A
((MAP-CVP)/CO) x 80
Norm= 800-1500
5
Q
metabolic equivalent
A
metabolic rate of specific physical activity/metabolic rate at rest
6
Q
trans pulmonary pressure
A
alveolar pressure-intraplural pressure
7
Q
Alveolar ventilation
A
(TV- dead space) x RR or CO2 production/PaCO2
8
Q
minute ventilation (VE)
A
TV x RR or Vt x RR
9
Q
dead space to tidal volume ration (Vd/Vt)
A
0.33 in SV patient, 0.5 in mechanical ventilation
PaCO2-PeCO2)/PaCO2 (PeCo2=partial pressure of CO2 in exhaled gas, not the same as ETCO2
10
Q
Law of Laplace cylinder
A
tension=pressure x radius
11
Q
Law of Laplace sphere
A
tension = (pressure x radius)/2
12
Q
Alveolar oxygen (PAO2)
A
FiO2 x (Pb - PH2O) - (PaCO2 / RQ) PH2O= humidity of inhaled gas, assumed to be 47 mmHg RQ= respiratory quotient, assumed to be 0.8 Normal 105.98 mmHg
Can estimate FiO2 x 6
13
Q
Respiratory quotient
A
Co2 production/O2 consuption= 200 mL/min / 250 mL/min =0.8
>1= lipogenesis (overfeeding)
<1= lipolysis (Starvation)
14
Q
Estimation of shunt %
A
Shunt increases 1% for every 20 mmHg A-a gradient
15
Q
TV
FRC
VC
A
TV= 6-8 mL/kg
FRC= 35 mL/kg
VC= 65-75 mL/kg
calculated with ideal body weight
16
Q
CaO2
A
O2 carrying capacity
(1.34 x SaO2 x Hgb) + (PaO2 x 0.003)
Normally 20 ml O2/dL
17
Q
DO2
A
O2 delivery
CaO2 x CO x 10
Normally about 1000 mL O2/min
18
Q
Normal H and H values
A
women 13 and 39
men 15 and 45
19
Q
VO2
A
O2 consumption CO x (CaO2-CvO2) x 10
3.5 mL/kg/min
250 mL/min in 70 kg patient
20
Q
Normal P50 O2
A
Where hgb 50% saturated by O2
26.5 mmHg
Lower= L
Higher= R
21
Q
Bicarb reaction in blood
A
70%
H2O + CO2 H2CO3(carbonic acid) H+ + HCO3-
Need carbonic anhydrase for first reaction
H+ buffered by Hmg
HCO3 transported in plasma, Cl- goes into cell
22
Q
Co2 bound to hemoglobin
A
23%
R-NH2 + CO2 RNH-CO2- + H+
23
Q
Co2 dissolved in plasma
A
7%
solubility coefficient 0.067 mL/dL/mmHg
24
Q
Vd/Vt
A
2ml/kg / 6mL/kg (normally 0.33)
increases to 0.5 in mechanical ventilation
25
FiO2
((Air flow rate x 21) + (O2 flow rate x 100)) / Total flow rate
26
Tidal volume with fresh gas coupling
Vt on ventilator - FGF during inspiration - vol lost to compliance
1. Convert fresh gas flow from L/min to mL/min
2. Multiple by FGF by the percentage of time in inspiration (1:2 IE= 33.33%)
3. Divide 2 by RR.
4. Add set Vt to 3.
Most new ventilators decouple so this does not apply
27
Reynold's number
(Density x diameter x velocity)/viscosity
Re<2000= laminar flow (dependent on gas viscosity)
Re > 4000= turbulent flow (depending on gas density)
2000-4000= transitional flow
28
Volume lost to circuit
Circuit compliance x peak pressure
Some of Vt used to expand circuit
29
mL of liquid anesthetic agent used per hour
Vol% x FGF in L/min x 3
30
calculating vaporizer output at elevation
Required dial setting= (normal dial setting x 760)/ambient pressure (mmHg)
Higher altitude= higher setting
Lower altitude= lower setting
31
reaction of CO2 with sodalime
CO2 + H2O = H2CO3 (carbonic acid)
H2CO3 + 2 NaOH = Na2CO3 + 2 H2O + heat
Na2CO3 + Ca(OH)2 = CaCO3 (calcium carbonate) + 2 NaOH (sodium hydroxide)
32
Absorbent capacities
Soda lime 26L of CO2 per 100 g
| Calcium hydroxide lime 10.6 L per 100g
33
reaction of CO2 with calcium hydroxide lime
CO2 + H2O= H2CO3
H2CO3 + Ca(OH)2 = CaCO3 + 2H2O + energy(heat)
No CO and very title compound A
Lower fire risk
Less absorbent capacity
34
Hydration of sodalime
13-20% by weight
35
Mapleson for SV and controlled ventilation
SV- A > DFE > CB
| CV- DFE> BC> A
36
Plateau pressure
Pressure in smal airways and alveoli after tital volume is delivered
During inspiratory pause
Barotrauma risk increased with pressure > 35 cm/H2O
Static compliance= tidal volume/ (plateau pressure- PEEP)
37
Peak inspiratory pressure
Maximum pressure during inspiration
| Dynamic compliance= tidal volume/ (PIP-PEEP)
38
Dysfunctional hemoglobin
Carboxyhemoglobin- absorbs 660 at same rate as oxyhemoglobin, Overestimates SpO2
Methemoglobin- absorbs 660 and 990 equally, Underestimates if > 85%
Overestimates if < 85%
39
SPO2
Oxygenated hgb/ (oxygenated hgb + deoxygenated hgb) X 100%
40
BP cuff sizing
length- long enough to wrap around 80% of arm
| width- 40% circumference of patients arm
41
Arm position and NIBP reading
10 cm= 7.4 mmHg change
| 1 inch= 2 mmHg
42
Mixed venous O2 saturation
```
SvO2= SaO2- (VO2/(Q x 1.34 x Hgb x 10))
Normal= 65-75%
```
```
VO2= oxygen consumption
SaO2= loading of hemoglobin in arterial blood
```
Need a PA cath to get blood from SVC, IVC, and coronary sinus together
43
Bipolar leads
I- lateral, CxA
II- inferior, RCA
III- inferior, RCA
44
Limb leads
AVR
AVL
Lateral
CxA
aVF
Inferior
RCA
45
Precordial
```
V1- septum, LAD
V2- septum, LAD
V3- anterior, LAD
V4- anterior, LAD
V5- lateral, CxA
V6- lateral, CxA
```
46
Axis deviation
Use lead 1 and aVF
+ and += normal (between -30 and +90)
- and -= extreme R
Leads are Reaching towards each other(I down and aVF up)= R (greater than 90)
Leads are Leaving each other (I up and aVF down)= L (less than -30)
47
Class 1 antiarrhythmic
Na+ channel blockers
1A- quinidine, procainamide, disopyramide
Phase 0 dep, prolonged phase 3 repol
1B- lidocaine, phenytoin
Phase 0 dep, shortened phase 3 repol
1C- flea indie, propafenone
Strong phase 0 dep
48
Class 2 anti arrhythmic
Beta blockers
| Slows phase 4 depol in SA node
49
Class 3 antiarrhythmic
K+ channel blockers
Amiodarone, bretylium
Prolongs phase 3 repolarization
Increased effective refractory period
50
Class 4 antiarrhythmic
Ca Channel blockers
Verapamil, dilt
Decreased conduction velocity through AV node
51
Torsades pneumonic
```
POINTES
Phenothiazines
Other meds- methadone, droperidol, haldol, zofran, halogenated agents, amiodarone, quinidine
Intracranial bleed
No known cause
Type I antiarhythmics
Electrolyte disturbances- low K, low Ca, low Mg
Syndromes- Romano ward, Timothy
```
52
EEG waveforms
Beta- high frequency, low voltage, awake or light anesthesia
Alpha- medium frequency, awake but restful with eyes closed
Theta- general anesthesia and children sleeping
Delta- low frequency, GA, deep sleep, and brain injury
53
Definition of pulmonary hypertension
PAP > 25 mmHg
54
PVR
((mean PAP - PAOP) X 80) / CO
| Norm= 150-250 dynes/sec/cm to the -5th power
55
Drugs you can give in ETT
NAVEL
| Narcan, atropine, vasopressin, epi, lidocaine
56
Objective measures of respiratory distress
Vital capacity (mL/kg)- <15
Inspiratory force (cm/H2O)- <25
Oxygenation at 21%- PaO2 <55, A-a gradient >55
Oxygenation at 100%- PaO2 < 200, A-a gradient >450
PaCO2 >60
RR >40 or <6
57
Indicators of postoperative pulmonary complications in patients undergoing pulmonary surgery
Airflow: FEV1<40% of predicted
Gas exchange: DLCO < 40% of predicted
Cardiopulmonary reserve: VO2 max < 15 mL/kg/min (normal male=35-40, normal female=27-31) (if can't climb 2 flights of stairs, this patient is at risk)
58
Double lumen tube placement
Male: size 39-41 fr, depth 29cm
Female: size 37-29 fr, depth 27cm
Children 8-9: 26 size
Childre >10 : 28 or 32 size
59
Lateral decubitus and V/Q
Nondependent- better ventilated
| Dependent- better perfused
60
Mallampati pneumonic
PUSH
| Pillars, uvula, soft palate, hard palate
61
Atlantoocciptal joint mobility
Normal flexion and extension: 90-165 degrees
| Normal extension: 35 degrees (difficult DL if less than 23 degrees)
62
Risk factors for difficult mask
```
BONES
Beard
Obesity- BMI>26
No teeth
Elderly- age>55
Snoring
```
63
NPO guidelines
2 hours- clear liquids
4hours- breast milk
6 hours- non human milk, solids, infant formula
8 hours- fatty food
64
Mendelson syndrome
risk factors- Gastric pH <2.5, gastric volume>25mL (0.4 mL/kg)
Risk reduced by clear liquids 2 hours before
65
Pressure for cricoid
Before LOC- 20 newtons or 2kg
| After LOC- 40 newtons or 4kg
66
large tongue pneumonic
Big Tongue
Beckwith syndrome
Trisomy 21
67
small chin pneumonic
```
Please Get That Chin
Pierre robin
Goldenhar
Treacher collins
Cru di chat
```
68
cervical spine anomaly pneumonic
Kids TRY Gold
Klippel-feil
Trisomy 21
Goldenhar
69
ETT size in peds
ETT without cuff- (Age/4) +4
| Depth- ID x 3
70
Total body water
```
42L in 70 kg adult male (60% of total body weight)
ICV 40% of total body weight or 28 L
ECV 20% of total body weight or 14 L
16% interstitial fluid 11L
4%plasma fluid (3L)
```
71
Plasma osmolarity
(Na x 2) + (glucose/18) + (BUN/2.8)
| normal= 280-290 mOsm/L
72
Solutions
Hypotonic 255 mOsm/L
Ex: NaCl 0.45%, D5W
Isotonic 285 mOsm/L
Ex: NaCl 0.9%, 5% albumin, LR, plasmalyte A, Voluten 6%, Vespan 6%
Hypertonic 315 mOsm/L
Ex: NaCl 3%, D5 NaCl 0.45% and 0.9%, D5 LR, Dextran 10%
73
Coagulopathy with synthetic colloids
Dextran > hetastartch> hextend
don't exceed 20mL/kg
not a problem with Voluten
74
PaCo2 impact on pH
Acute respiratory acidosis
PaCO2 increases 10mmHg= pH decrease 0.08
Chronic respiratory alkalosis
PaCO2 increases 10mmHg= pH decrease 0.03
75
anion ion gap
Major cations - major anions
Na - (Cl + HCO3)= 8-12 mEq/L
accumulation of acid= gap acidosis (Anion gap >14)
loss of bicarb or ECF dilution= non gap acidosis (anion gap <14)
76
anion gap acidosis pneumonic
```
MUDPILES
Methanol
Uremia
Diabetic ketoacids
Pareldehyde
Isoniazid
Lactate
Ethanol, ethylene glycol
Salicylates
```
77
non anion gap acidosis pneumonic
```
HARDUP
Hypoaldosteronism
Acetazolamide
Renal tubular acidosis
Diarrhea
Ureterosigmoid fistula
Pancreatic fistula
```
78
Net filtration pressure
(Capillary hydrostatic pressure- interstitial hydrostatic pressure) - (plasma oncotic pressure- interstitial oncotic pressure)
79
Na concentration in fluids
any solution with NaCl (including 5% albumin)= 154mEq/L
any solution with LR= 130 mEq/L
plasmalyte= 140 mEq/L
80
Clotting factors pneumonic
```
Foolish people try climbing long slopes after Christmas, some people have fallen
1- fibrinogen
2- prothrombin
3- tissue factor
4-calcium
5- labile factor
7- stable factor
8- anti hemophilic factor
9- Christmas factor
10- Stuart prower factor
11- plasma antithrombin antecedent
12- Hageman factor
13- fibrin stabilizing factor
```
81
Extrinsic pathway
For 37 cents, you can purchase the extrinsic pathway
very fast
82
Intrinsic pathway
If you can't buy the intrinsic pathway for $12, you can buy it for $11.98
slower, can take up to 6 min
83
final common pathway
The final common pathway can be purchased at the 5 and dime(X) for 1 or 2 dollars on the 13th of the month
84
volume of distribution
amount of drug/desired plasma concentration
85
loading dose
vd x desired plasma concentration/bioavailability
bioavailabiity=1 with IV drug
86
extraction ratio
(arterial concentration- venous concentration)/arterial concentration
flow limited >0.7- increased blood flow increases clearance
capacity limited <0.3- changes in enzymes impact clearance, not impacted by blood flow
87
low hepatic ratio drugs
roc, diazepam, lorazepam, methadone, thiopental, theophylline, phenytoin
88
aPTT
norm 25-32 sec
measures intrinsic and common
Factors reduced by 30% for changes in #
response to unfractionized heparin, NOT LMWH
89
PT/INR
norm 12-14 sec
measures extrinsic and common
Factors reduced by 30% for changes in #
response to warfarin
norm 1
standardized form of PT
90
Bleeding time
norm 2-10min
| prolonged by aspirin and NSAIDs
91
ACT
norm 90-120 sec
heparin dosing
>400 for bypass
92
Cranial nerve pneumonic
Oh Oh Oh To Touch And Feel Virgin Girls Vagina and Hymen
| Some Say Marry Money But Brother Says Bad Business to Marry Money
93
CSF flow pneumonic
Love My 3 Silly 4 Lorn Magpies
```
Laternal
Monroe
3rd ventricle
Sylvius
4th ventricle
Luschka
Magendie
```
94
Cerebral blood flow
cerebral perfusion pressure/ cerebral vascular resistance
95
CMRO2
3-3.8 mL/O2/100g brain tissue/min
| Decreases by 7% for every 1 degree celsius
96
CPP
MAP - ICP or CVP (whichever is higher)
autoregulation 50-150
97
PaCO2 in brain
At PaCO2 of 40mmHg, there is 50mL/100g brain tissue/min
every 1mmHg increase in PaCo2=1-2mL increase in good flow
Max vasodilation @ 80-100mmHg
Max vasoconstriction @ 25mmHg
metabolic acidosis does not impact CBF
98
PaO2 in brain
below 50-60mmHg=vasodilation and increases CBF
99
hyperventilation and brain
PaCo2 30-35 mmHg
less than 30 increases risk due to vasocontriction and left shift of curve
effect lasts 6-20 hours
100
therapy for vasospasm
```
hypervolemia
hypertension
hemodilution- hit 27-32%
nimodine is only Ca channel blocker used
daily transcranial doppler
```
101
Cerebral salt wasting syndrome
Occurs with SAH
from brain releasing natriuretic peptide
treated with isotonic crystalloids
Not SIADH
102
Artery of Adamkiewicz
perfuses anterior cord in thoracolumbar region
| most commonly T11-12 (75% of population T8-12, L1-2 in other 10%)
103
Anterior spinal artery syndrome
also known as Beck syndrome
when aortic clamp is place above artery of adamkiewicz
symptoms- flaccid paralysis of lower extremities, bowel and bladder dysfunction, loss of temp and pain, preserved touch and proprioception
104
tracts perfused by anterior spinal arteries
corticospinal tract- causes flaccid paralysis
autonomic motor fibers- causes bladder and bowel dysfunction
spinothalmic tract- causes temp and pain loss
105
tracts perfused by posterior spinal arteries
dorsal column- touch and proprioception
106
dorsal column medial leminiscal
fine touch, proprioception, vibration, and pressure
large, myelinated fibers
rapidly conduction (faster than anterolateral)
1st order- periphery to medulla
2nd order- medulla to thalamus (crosses)
3rd order- thalamus to parietal lobe
107
Spinothalmic tract
anterolateral system
pain, temp, crude touch, tickle, sexual sensation
smaller, myelinated, slower conduction
1st order- periphery to spinal cord (ascends or descends 1-3 levels in Lissauer tract before synapse)
2nd order- dorsal horn of cord to RAS or thalamus (in anterior or lateral spinothalmic tract)
3rd order- to thalamus
108
Corticospinal tract
Pyramidal system
Most important motor pathway
Lateral- cross in medulla, to limb muscles
Ventral- remain on ipsilateral side and descend into cord (typically in cervical or thoracic), axial muscles
upper motor neuron injury- hyperreflexia and spastic paralysis, Tested by Babinski
Lower motor neuron- ventral horn to NMJ, injury: paralysis on same side, impaired reflexes and flaccid paralysis , no babinski
109
Dantrolene dosing
2.5 mg/kg IV, repeat 5-10min
1mg/kg for 6 hr infusion, or 0.1-0.3mcg/kg/hr for 48-72 hrs
if more than 20mg/kg reconsider diagnosis
20mg dantrolend and 3g mannitol per bottle
constituted with 60 mL preservative free water
110
Ryanodex
2.5mg/kg IV
| container 250 mg dantrole with 5mL sterile water diluent
111
diseases linked to MH
king-denbourough syndrome
central core disease
multiminicore syndrome
112
adrenal medulla secretion
80% epi, 20% norepi
| NE to epi conversion occurs in the adrenal mudella
113
metabolites of NE
preliminary- metanephrine, normetanephrine
final- vanillylmandelic acid (3 methoxy-4-hydroxymandellic acid)
elevated VMA in urine = pheochromocytoma
114
Autonomic efferent pathway
Preganglionic efferent- myelinated B fiber, releases acetylcholine onto nicotinic type N receptor in autonomic ganglion
Post ganglionic efferent- nonmyelinated C fiber, PNS releases AcH onto effector organ, SNS releases NE onto effector organ (a few exceptions)
115
SNS exceptions
postganglionic releases Ach onto N receptors of sweat glands, pilorector muscles, and some vessels
no postganglionic at adrenal medulla, chromafin cells release NE and epi into circulation
116
ANS post to preganglionic ratio
SNS- 30:1, causes postsynaptic amplification
| PNS- 1-3:1, precise control
117
White rami
Preganglionic sympathetic fibers enter cord through ventral horn
get into sympathetic chain on white rami (myelinated)
118
Grey rami
after exiting chain, reenter spinal nerve on grey rami to real with it to target organs
sweat glands, pilorector muscles, and vasculature
119
Horner syndrome
```
blockade of stellate ganglion, happens on ipsilateral side
Very Homely PAM
Vasodilaiton
Horner
Ptosis
Anhydrosis
Miosis
(also enopthalmus)
```
120
resting rate of NE and epi release from adrenal medulla
NE- 0.05 mcg/kg/min
| epi- 0.2 mcg/kg/min
121
Baroreceptor sensors
Carotid sinus- in internal carotid right after bifurcation, carotid sinus nerves (nerves of Hering) converge with glossopharyngeal
Transverse aortic arch- sends info via vagus nerve
122
Beta 1 selective antagonists
```
MABE AB
Metoprolol
Atenolol-kideny is primary route of elimination
Betaxolol
Esmolol- RBC esterases
Acebutolol
Bisoprolol
```
123
Nonselective beta antagonists
Labetolol- mixed beta and alpha, 7:1, intrinsic sympathomimetic activity
Timolol
Propranolol
Pindolol- intrinsic sympathomimetic activity
Nadolol
Carvediolol- mixed beta and alpha, 10:1
124
Alpha blockers
Phentoalamine- short acting, nonselective, competitive alpha blocker
Phenoxybezamine- long acting, non selective, noncompetitive alpha blocker
Prazosin- selective alpha 1
125
Origin of efferent SNS pathways
T1-L3
axons exit via ventral roots
synapse in 22 sympathetic ganglia
126
Origin efferent PNS pathways
CN 3,7,9,10
Sacral 2-4
synapse on effector organ
127
Catecholamines by size
smallest to largest
| dopamine, NE, epi, isoproterenol, dobutamine
128
Renal medulla structures
loops of henle, collecting ducts
129
Kidneys portion of CO
20-25%, 1000-1250 mL/min
130
Livers portion of CO
30%, 1500mL/min
131
Blood and O2 puppy to liver
Hepatic artery- 25% blood flow, 50% O2
| Portal vein- 75% blood flow, 50% O2
132
Portal vein pressure values
7-10, >20-30=portal hypertension
133
hepatic arterial buffer response
hepatic artery perfusion pressure= MAP- hepatic vein pressure
mediated by adenosine
134
coag factors not produced by hepatocytes
Von Willebrand factor- vascular endothelial cells
Factor 4
Factor 3- vascular endothelial cells
Factor 8- liver sinusoidal cells and endothelial cells
135
end of subarachnoid space in adults and children
adults- S2
| children- S3
136
Spine landmarks
L1- conus medullaris
L4-5 interspace= Tuffier's line (correlates with iliac crests)
S2- dural sac ends (correlates with superior iliac spines) (S3 in neonates)
S5- sacral hiatus and sacrococcygeal ligament
137
Spinal differential blockade
1. autonomic fibers
2. sensory fibers
3. motor fibers
autonomic block 2-6 dermatomes higher than sensory
sensory block 2 dermatomes higher than motor
138
Epidural differential blockade
no autonomic differential
| sensory block 2 dermatomes higher than motor
139
order of block onset by nerve fibers
1. B- preganglionic ANS
2. C- postganglionic sympathetic, slow pain, temp, touch
3. A gamma- skeletal muscle tone, A delta- fast pain, temp, touch
4. A alpha- skeletal muscle motor and proprioception, A beta- touch, pressure
pre ganglionic sympathetic, temp, pin prick (fast pain), touch, motor
140
valve lesions to consider with neuraxial
severe aortic stenosis
severe mitral stenosis
hypertrophic cardiomyopathy
141
MS and neuraxial
epidural safe
| spinal may exacerbate symptoms
142
CSF specific gravity
1.002-1.009
143
Baricity of LA
dextrose= hyperbaric
NS= isobaric
water= hypobaric
EXCEPTION- 10% procaine in water is hyperbaric
144
depth of epidural catheter
3-5cm into epidural space
145
caudal anesthesia kids dosing
sacral- 0.5 mL/kg
sacral to T10- 1mL/kg
sacral to mid thoracic- 1.25mL/kg
can add clonidine 1mcg/kg
no dose greater than 2.5-3mg/kg
146
caudal anesthesia adult dosing
sacral: 10-15 mL
sacral to T10: 20-30mL
sacral to mid thoracic- NA
147
side effects of neuraxial opiods
pruritis- most common
respiratory depression
urinary retention- most common in young males
N/V
148
conus medullaris
adult: L1-2
neonate: L3
end of SC
149
cauda equina syndrome
exposure of high concentration to LA's
5% lido and micro spinal catheters
bowel/bladder dysfunction, paralysis, sensory deficits
supportive treatment
150
transient neurologic syndrome
unlikely it is caused by toxicity
lidocaine, lithotomy, knee scope, ambulatory surgery
severe back pain radiating to butt and legs
within 6-36 hours and resolves in 1-7 days
NSAIDs, opioids, and trigger point injections
151
most resistant nerve roots to LA
L5 and S1
| Largest spinal nerves
