CA1 Flashcards
(155 cards)
1
Q
What does NIBP measure?
A
MAP
2
Q
What is SaO2 and how is it calculated
A
Fractional Oxygen O2Hb/(O2Hb + COHb+MetHb)
3
Q
What at high levels cause SpO2 to be 85% and what happens at different levels of SaO2?
A
Methemoglobinemia; SaO2 >85% falsely low reading and SaO2 <85% falsely high reading
4
Q
What does CO reading do to SpO2?
A
Creates a falsely high SpO2 reading due to similar absorbance to O2Hb
5
Q
When does cyanosis appear?
A
@ Hgb of 15 SaO2 of 80% and Hgb of 9 SaO2 of 66%
6
Q
How sensitive is using two leads II and V5 in predicting ischemic events?
A
80%
7
Q
How do you calculate Systolic and Diastolic BP with MAP?
A
MAP = (SBP +2DBP)/3 = DBP + (pulse pressure)/3
8
Q
How does blood pressure change with change in height?
A
pH 7.410 for every 10 cm of height change 7.4 mmHg
9
Q
How does EtCO2 change when patient goes apneic
A
Will increase 6 mmHg first minute and 3 mmHg every minute after that
10
Q
What is gold standard of temperature source?
A
Pulmonary artery temperature
11
Q
For inhalation agents what measure effect of the gas?
A
Partial pressure not concentration therefore atmospheric pressure matters => higher altitude = less effective at the same concentration
12
Q
What does high cardiac output do to anesthetic reaching the CNS
A
You need more, there is more in the “tank”
13
Q
How do different shunts effect volatile anesthetics
A
Right to left shunt (and mainstem) causes dilution of volatile gas.
Left to right shunt doesn’t do anything
14
Q
Explain the second gas effect
A
The effect of a second agent increases the concentration of the other gas (i.e nitrous)
15
Q
Potency of volatile anesthetic is linked to what?
A
Lipid solubility
16
Q
What are the effects of volatile agents on neuro
A
Decreases CMRO2 and CVR but increases CBF and ICP
Nitrous Increases CMRO2 and CVR
0.5 mac of sevo/iso/des decrease CMRO2 and CBF is okay
1 mac of sevo/iso/des decreases CMRO2 substantially and CVR decreases therefore CBF increases
17
Q
What are the effects of volatile agents on cardiac
A
Decrease in SVR and MAP, but maintains CO except halothane decreases contractility
18
Q
Effects of volatile agents on Pulm
A
Decrease tidal volume, increased RR in order to maintain minute ventilation
Bronchodilation
19
Q
Effects of volatile agents on renal
A
Decrease renal blood flow and decrease in GFR
20
Q
Effects of volatile agents on MSK
A
increases muscle relaxation except N2O
21
Q
Pros of N2O
A
Pros:
Quick on and off
NMDA antagonist
No malignant hyperthermia
22
Q
Cons of N2O
A
Cons:
- Mac of 104% only adjunct, low potency
- PONV
- If pulmonary cavities or blebs can cause tension pneumo
- Pulm HTN for prolonged exposure
- Bone marrow suppression with prolonged exposure
23
Q
Pros of Iso
A
Pros:
Second most potent
Least expensive
Mac of 2 causes silent EEG
24
Q
Cons of ISO
A
Cons:
- Coronary vasodilator => coronary steal syndrome
- Decreases BP and increases CBF @ mac 1.6 and ICP mac above 1
25
Things to know about Sevo and the carbon dioxide desicator
Can create CO
Can create Compound A and found to be nephrotoxic in rats therefore keep flows atleast 2 L/min so rebreathing does not happen.
26
Things to know about desflurane
- Low potency
- high vapor pressure
- Very pungent => When given to awake patient => Can cause breath holding, bronchospasm, laryngospasm, cough, salivation
- Can cause increase HR and BP when increased rapidly
27
At what MAC does 95% of patients no respond to incision?
MAC 1.3
28
What is MACaware
MAC necessary to prevent response to tactile or verbal response
volatile = 0.4 and N2O = 0.6
29
MAC movement
MAC 1.0 prevents movement
30
MAClaryngoscope,LMA,intubation
MAC 1.3
31
MACBar
MAC to reach blunted autonomic response to noxious stimulus
MAC 1.6 with use of opiate and nitrous
32
When is MAC highest and how does it depreciate?
Highest at 6 mo old
after 40 y/o decreases 6% for every decade
33
What factors require higher MAC?
- Amphetamine, ephedrine, L-Dopa, and TCA => Inhibition of catecholamine reuptake
- Chronic alcohol abuse
- <6 mo yo
- Hyperthermia
- Hypernatremia
-Gingers
34
What pathophysiological conditions causes requiring less MAC
- Hypothermia
- Hypoxia
- Hypercarbia
- Severe anemia Hgb<5
- Sepsis
- Hyponatremia
- Acute EtOH intoxication
35
Propofol Induction dose
1.5-2.5 mg/kg
36
Propofol effects on Neuro
Decrease CMRO2, CBF, ICP
37
Propofol effects on CV
Decreases SVR, direct myocardial depressant
38
Propofol effect on Pulm
Dose-dependent respiratory depression
39
Propofol things to know
- Pain on injection
- Antiemetic properties
- Anticonvulsant
40
Etomidate induction dose
0.2-0.3 mg/kg
41
Etomidate effects on neuro
Decreases CMRO2, CBF, ICP
42
Etomidate effects on CV
Maintains hemodynamic stability (minimal cardiac depression)
43
Etomidate effects on pulm
Minimal respiratory depression (no histamine release)
44
Etomidate things to know
- Pain on injection
- High PONV
- Myocolonus
- Inhibits adrenocoritical axis (inhibits 11-beta-hydroxylase)
45
Ketamine induction dose
1-2 mg/kg
46
Ketamine effects on neuro
Increases CMRO2, CBF, and ICP
47
Ketamine effects on CV
Cardio-stimulating effects (negatively effects mycoardial supply-demand)
48
Ketamine effects on pulm
Minimal respiratory depression; bronchodilation, most likely protect airway reflexes
49
Ketamine things to know
- Analgesic effects
- NMDA antagonist
- Can be used in chronic pain patients
50
Midazolam induction dose
1-2 mg
51
Midazolam effects on neuro
Decreases CMRO2, CBF, and ICP; does not cause burst suppression on EEG
52
Midazolam effects on CV
Decreases SVR and BP
53
Midazolam effects on Pulm
Dose-dependent respiratory depression
54
Midazolam reversal drug
Flumazenil
- Very short acting
- Can see re-sedation as benzo is eliminated more slowly compared to effects of flumazenil
55
Dexmedetomidine target
selective alpha2-adrenergic agonist (primarily central)
56
Dexmedetomidine main side effect
Bradycardia, heart block, and hypotension
57
What drug can you use to awake FOB intubations for sedation
Dexmedetomidine
58
What part of the brain is effected by the mu receptor agonism?
Periaquaductal gray matter
59
What part of the spinal cord is effected by the mu receptor agonism?
Substantia gelatinosa
60
Side effects of opiates
- Sedation, Respiratory depression, chest wall rigidity
- Bradycardia, hypotension (when given with other agents)
- Itching, nausea, ileus, urinary retention
- Miosis
61
What does opioids do to MAC of volatile anesthetics?
Reducses MAC required
62
Fentanyl peak onset and duration
Peak onset: 3-5 minutes
| Duration of action: 30-60 minutes
63
Things to know about fentanyl
- Very long context-sensitive half-life limits therefore:
1) Cut dose in half every 2 hours
2) prolonged duration of action with repeated boluses intraop
64
Things to know about remifentanil
- Max does 0.3 mcg/kg/min
- Rapid metabolism and will last 5-10 min regardless of infusion duration due to almost no context-sensitivity of half-life
- Useful to use for neuromonitoring and NMBA cannot be used to have the patient not move
- Bradycardia is the most common: Have some glyco or atropine
65
Things to know about Sufentanil
- Has some context-sensitive half-life with some accumulation
- Typical infusion dosing: Divide case into thirds
0.3 mcg/kg/h -> 0.2 -> 0.1 and turn off 15-30 minutes before end of surgery
66
What to watch out for meperidine (demerol)
-Toxic metabolite (normeperidine) lowers seizure threshold
- Anticholinergic side effects
- Avoid using with MAOIs
- Libby Zion Law: interacts with Haldol
-Common use is for Postop shivering common in younger patients
67
What are some opioids to consider for ENT cases
Remifentanil or Sufentanil for narcotic wake up with less bucking and good post-op analgesia
68
Which opioids do you want to avoid in renal patients?
Demerol (meperidine) and morphine due to active metabolites.
69
How to calculate SVR with CO and how to calculate CO
```
MAP-CVP = CO x SVR or V=I x R
CO = HR x SV
```
70
How to calculate SVR and normal range
SVR = [(MAP-CVP)/CO]x80 normal range 800-1200 dynes
71
Differential for narrow pulse pressure
<25 mmHg
- Aortic stenosis
- Coarctation of the aorta
- Tension pneumothorax
- Myocardial failure
- Shock
72
Differential for wide pulse pressure
>40 mmHg
- Aortic regurgitation
- Atherosclerosis
- PDA
- Thyrotoxicosis
- AVM
- Pregnancy
- Anxiety
73
Intraoperative HTN ddx
- Light anesthesia
- Pain
- Chronic HTN
- Illicit drug use
- Hypermetabolic state (MH, thyrotoxicosis, NMS)
- Elevated ICP (Cushing's triad => HTN, bradycardia, irregular respirations)
- Autonomic hyperreflexia
- Endocrine
- Hypervolemia
- Iatrogenic (epi + local)
- Hypercarbia
74
DDX of intraop hypotension
- Measurement error
- Hypovolemia
- Drugs
- Regional anesthesia
- Surgical events
- Cardiopulmonary problems
- Acidosis and hypocalcemia must be treated before giving vasoactive drugs
75
Mechanism of action for succinylocholine
ACh receptor agonist depolarizing NMBA
76
Succinylocholine intubation dose
1-1.5 mg/kg
77
Onset of succinylocholine
30-60 seconds
78
How long does succinylocholine last?
~10 minutes
79
Contraindications for Succinylocholine
- HyperK and usual induction dose increases K ~0.5 mEq/L.
- Avoid in burn patients, muscular dystrophy, myotonias, prolonged immobility, crash injury, upper motor neuron insults from stroke and tumors
- MH
- Open globe
80
Mechanism of action of nondepolarizing NMBA
-Competitive inhibition of nicotinic Ach receptor at NMJ
81
RSI and normal intubating dose for ROC
1.2 mg/kg and 0.6 mg/kg
82
What NMBA do you use for renal or hepatic patients? and why?
Cisatracurium
| Eliminated by Hofmann reaction
83
When do you know when NMBA is fully reversed?
TOF of 0.9 when comparing the 4th to the 1st twitch or 5 seconds of sustained tetanus @ 50-100 Hz wi/o fade
84
Where do you check for twitches to assess different muscles?
Diaphragm => corrugator supercilii
Pharyngeal muscles and readiness for extubation => adductor pollicis
85
Side effects of neostigmine
Muscarinic vagal side effects (bradycardia, GI stimulation, bronchospasm)
86
How do you dose neostigmine with glyco
40-50 mcg/kg never more than 70 mcg/kg
and give 1/5 of the amount of glyco with the neostigmine
87
When do you not use sugammadex
- Hormonal contraceptives for next 7 days will not work
- Severe renal insufficiency
- PTT and PT prolonged by 25% for 60 mins
- Do not mix with Zofran, verapamil and ranitidine
Anaphylaxis
88
Things to worry about for difficult or impossible face mask ventilation
MaMaBOATS:
- Mallampati III or IV
- Mandibular protrusion decreased
- Beard
- Obesity/OSA
- Age >57-58
- Teeth lacking
- Snoring
89
How to ramp?
Tragus is aligned with sternum and parallel to the floor
90
What are the three axis you want to line up for intubation?
Oral axis,
Pharyngeal axis
Laryngeal axis
91
How do you know a patient is volume responsive when using pulse pressure variation?
If their PPV > 10%
92
Total body water for males and females
Males: weight x 60%
Females: weight x 50%
93
Total body water components
67% intracellular + (25% interstitial + 8% intravascular)=extracellular
94
Total body water weight distribution
5% of weight intravascular- 15% interstitial - 40% intracellular
5-15-40
95
What does aldosterone do to fluid status
Sodium reabsorption and increase intravascular volume
96
What does ADH/Vasopressin do?
Water reabsorption
97
What does atrial natriuretic peptide do?
Sodium and water excretion
98
NS advantages
Preferred for brain injury/swelling due hyperosmolar
99
NS disadvantages
Hyperchloremic metabolic acidosis
100
LR advantages
more "balanced"
101
LR disadvantages
Potassium for renal patients
| Ca maybe interferes with citrate's chelating properties in pRBCs
102
What type of patients should you use colloids?
- Cirrhotics
- Burn patients
- Hemorrhagic shock with no blood => 1cc of colloid per cc of blood loss
103
half life of colloid and crystaloid intravascular
colloid => 3-6
| Crystaloid => 20-30 mins
104
Fluid management rules
4-2-1 rule = 40+weight
105
How to give fluid deficits back
1/2 over 1st hour
1/4 over 2nd hour
1/4 over 3rd hour
106
How much evaporative loss happens in minimal tissue trauma (hernia repair)
0-2 ml/kg/hr
107
How much evaporative loss happens in Moderate tissue trauma (open cholecystectomy)
2-4 ml/kg/hr
108
How much evaporative loss happens in severe tissue trauma (bowel resection)
4-8 ml/kg/hr
109
How to calculate blood loss
1 lap = 100-150 ml
4x4 = 10 ml each
Suction canister
110
How to replete volume to burn patients
Parkland Formula
Give 2cc/kg x %BSA over first 8 hours
Give 2cc/kg x %BSA over next 16 hrs
111
How to calculate %BSA?
Rule of nines
112
Minimum UOP during surgery
0.5 cc/kg/hr
113
How to calculate IBW
46 + 2.3 inch above or below 5 ft = females
50 + 2.3 inches above or below 5 ft = males
114
Arterial O2 content equation
CaO2 = HbO2 + Dissolved O2
=(Hb x 1.36 x SaO2) + (PaO2 x 0.003)
NL = 20 cc O2/dl
115
Estimated blood volume for Male and female adult
70 cc/kg = male
| 65 cc/kg = female
116
Complications to think about with giving blood
1) Hypothermia => give it in a warmer
2) Coagulopathy (dilutional)
3) Citrate toxicity => Ca chelator
4) Acid-base
5) Hyperkalemia (K moves out of pRBCs during storage)
6) Impaired O2 delivery capacity (2,3 DPG)
117
How to think about transfusion reactions according to fever or no fever and acuity
Fever:
Acute: Acute hemolytic, Febrile Non-hemolytic, Transfusion -related sepsis, Trali
Delayed: Delayed hemolytic, TA-GVHD
No Fever:
Acute: Allergic, hypotensive, TACO
Delayed: Delayed serologic, post-transfusion purpura, Iron overload
118
What type of patient usually get anaphylactic rxn to blood products?
-IgA deficiency get washed blood
119
What is TACO?
Tranfusion associated circulatory overload => get volume reduced blood for CHF patients
120
Dyspnea, hypoxemia, hypotension, fever, PE post transfusion
TRALI => Transfusion Related Acute Lung Injury
4-6 hours post transfusion
121
Causes of hypoxemia
```
Low FiO2
Hypoventilation
Diffusion impairment
Shunt
V/Q Mismatch or Deadspace
```
122
What is Alveolar gas equation?
what is normal partial pressure of arterial O2
PAO2 = FiO2 (760-47) - (PaCO2/0.8) = 100 mmHg
normal PaO2 = 103 - age/3
123
Normal A-a gradients
<10 mmHg on RA
<60 mmHg on 100% O2
< (age/4) + 4
a/A ration > 0.75
124
Steps to think about during hypoxemia
1) Listen to Lungs
2) Check ETT
3) Check Circuit
4) Check machine
5) Check monitors
125
How to manage hypoxemia
1) Patient on 100% FiO2
2) Recruitment maneuver 30 sec at 30 mmHg and add PEEP
3) ETT placement by auscultation
4) Suction airway and ETT
5) CV issues with CO
6) Send ABG/VBG
126
Mixed Venous O2 content
CvO2 = O2 Hb + Dissolved O2
PvO2 = 40
CvO2 = 15 cc O2/dl
127
O2 Delivery equation
CO x CaO2
= 5 L/min x 20 cc O2/dl
=1 L O2/min
128
O2 consumption
Fick equation
VO2 = CO x (CaO2 -CvO2)
=5 L/min x 5 cc O2/dl
250 cc O2/min
129
Hyperkalemia effect on EKG
Peaked T waves with prolonged PR segment to drop of P wave with widening to QRS to sine waves
130
Treatment for hyperK
Stabilize cardiomyocyte by giving calcium
Shift K intracellular Sodium bicarb, insullin, albuterol
Remove potassium: kayexalate, sorbitol, diuretics, and dialysis
avoid acidosis and treat acidosis
131
EKG changes for hypokalemia
U wave
132
Signs and symptoms of hypermagnesemia
EKG (wide QRS, long PR, bradycardia)
Hypotension (vasodilation, mycoardial depression)
133
Signs and symptoms of hypomagnesemia
EKG (long QT, PACs, PVCs, afib)
Seizures
134
Drawbacks of hypothermia
1) infection x 3 fold
2) wound healing
3) Coagulopathy
135
Patient related risk factors for PONV
Young, female, non-smoker, with hx of PONV or motion sickness
136
Which drugs give you PONV
1)Volatile anesthetics
2 Post-op Narcotics, neostigmine
3)Aggressive hydration causing gut edema
137
Surgery related things for PONV
>2 hours
138
What is the mechanism of action of zofran and what is a common side effect
5-HT3 antagonists and headache
139
What does promethazine (phenergan) do?
Dopamine antagonist as well as H1 antagonism
140
What does metoclopramide (Reglan) do and who to avoid in?
Dopamine antagonist, can cause extrapyrammidal SE therefore do not give it to Parkinson's patient
141
Larynx innervations
Recurrent laryngeal (CNX) most of the motor
Superior Laryngeal
- internal branch
- External branch: motor of cricothyroid
142
What nerve mediates laryngospasm?
-superior laryngeal nerve
143
How to manage laryngospasm
1) Jaw thrust, head tilt, oral or nasal airway
2) Suction oropharynx
3) CPAP => bag mask
4) Propofol or IV lidocaine
5) Sux
6) Reintubate vs surgical airway
7) Monitor for post-obstructive negative pressure pulmonary edema
144
NPO guidelines
```
Clears 2 hrs
Breast milk 4 hrs
Formula 6 hrs
non-human milk 6 hrs
Light meal 6 hrs
Fatty meal 6-8 hrs
```
145
Anaphylaxis epi dose
10-100 mcg IV boluses
0.3-0.5 mg IM
146
What is the biggest cause of anaphylaxis in the OR
NMBA
147
Lidocaine max dose
4.5 mg/kg
| w/ epi 7 mg/kg
148
Bupivacaine max dose
2.5 mg/kg with epi 3 mg/kg
| => 0.25%
149
What are the CNS effects of Local Anesthetic toxicity
-Lightheadedness, tinnitus, tongue numbness, metallic taste -> CNS excitation -> CNS depression, seizure -> coma
150
What are the CV effects of LAST
- Bupi worse than lido
- Dose dependent blockade of Na channels -> bradycardia, ventricular dysrhythmias, decrease contractility, CV collapse, circulatory arrest
-3x the amount of local is required to produce CV toxicity than CNS
151
Treatment of LAST
Intralipid kit
| -1.5 cc/kg bolus 20% intralipid
152
Triggers of Malignant hyperthermia
Inhalational agents and sux
153
Sx of MH
1) increased HR and BP
2) tachypnea
3) increased temperature 1-2 degrees C every 5 minutes
first signs are trismus, but often hypercarbia will be first sign
154
Treatment for MH
-Dantrolene or ryanodex
155
When should abx prophylaxis be ideally given?
within 60 minutes of surgical incision ideally 15-45 minutes
