Test 4 Flashcards
top 5 variables associated with 30-day mortality age > 80
- ASA status
- preop albumin
- emergency
- preop functional status
- preop renal impairment
frailty domains
- unintentional weight loss > 4kg past year
- exhausting (effort and motivation assessed)
- grip
- walking speed
- low physical activity
include in PACU handoff
- surgical/anesthetic course
- preop conditions warrant/influenced outcomes
- treatment plan
most common cause of airway obstruction immediately post op
loss of pharyngeal tone in the sedated/obtunded
cause of most upper AW obst
tongue
laryngospasm succs doses: IM/IV
IM: 2-4 mg/kg
IV: 0.1 - 0.2 mg/kg
PaO2/SaO2 value of hypoxemia
PaO2 < 50
SaO2 < 90
most common cause of post op hypoxemia
atelectasis
hypoxemia + hypoventilation =
give O2
done
This describes binding of O2 to Hg reducing Hg CO2 affinity.
Haldane effect
This describes process where inc concentrations of CO2 will decrease O2 affinity to Hg
Bohr effect
what is P50 on Hg Dis Curve
normal value
PaO2 value at which Hg is 50% saturated with O2
normal P50: PaO2 of 26-7 results in 50% of Hg saturation
derrangement of K+ and Mag in which directions will potential NMBAs
Dec K+
Inc Mag
(also hypothermia and acidosis.. ur welcome)
alveolar gas equation
lets hear it
room air
0.21 (BP - PH20) - (CO2/ 0.8)
FiO2 25% (1L O2)
0.25 (760 - PH2O) - (CO2/0.8)
MV increases ___ L for every ___ increase in PaCO2
MV increases 2 L for every 1 mmHg increase in PaCO2
why give narcan slow
what doses
pulm edema
40-80 mcg per dose give slow
overall, the most common cause of pulm edema perioperatively
laryngospasm
TRALI: menifestation time, signs/sx/dx/tx
menifestation: 1-2 hr post transfusion (can be 6 hrs)
sx:
fever, hypotension (noncardiogenic pulm edema)
leukopenia (dec WBC) sequestered in lungs
dx: bilat pulm infiltrates, inc A-a gradient
tx: O2 and diuresis
virchow’s triad
lets hear it
- venous stasis
- hypercoagulability
- endothelial injury
post op PE related to
surgical trauma
liberation of Tissue Factor (TF) from subendothelial tissue into blood
stimulates thrombin=> clots
surgical induced hemostatic changes: mostly everything increased in chart except endogenous anticoags which are what?
all these decrease causing risk for clots:
- antithrombin III
- heparin cofactor II
- tissue factor pathway inhibitor
- protein C
- protein S
normal aPTT
30-40
minor blood aspiration removed by
cough
resorption
phagocytosis
at risk for gastric aspiration
- obese
- prego
- hiatal hernia
- PUD
- trauma
chemical pneumonitis occuring during anesthesia as a result of gastric aspiration
Mendelson’s syndrome
bronchospasm associated drugs
- morphine
- demerol
- succs
- atracurium
- thiopental
- mivacurium
histamine related (caution w/ asthma/copd)
late cariac signs of inadequate oxygenation
bradycardia
hypotension
most common cause of CV complication after non-cardiac sx
MI
most common underlying cause of sudden cardiac arrest: 2 things
ischemia
and/or
LV dysfunction
In PACU: hypotension is most commonly caused by
hypovolemia
Hypotension slides
- myocaridal dysfunction treated with
- secondary dysfunction treated with
coronary vasodilators
inotropics
afterload reduction agents
secondary
stop med causing issue
lab confirming allergic reaction
no differentiation btw anaphhylactoid (no prior exposure required) and anaphylactic (prior sensitization necessary)
tryptase
____ is leading cause of HTN and tachycardia in PACU and produces pressor response called _________ ____.
pain is leading cause of HTN and tachycardia in PACU and produces pressor response called somatosympathetic reflex
relationship btw cooling and catecholamine system
hypothermia causes endocrine induced CATs
as cooling occurs vessels are more responsive to CATs
hypothermia effect on cardiac cycle
prolongs refractory period
(brady, afib)
pharyngeal funcition returns to adductor pollicis at what TOF ratio
0.9
ability to bite down tongue blade/ett corresponds to TOF of
0.85
alcohold withdrawal can result in ___ ____ - hallucinations, extreme combativeness, and confusion
delirium tremens
four categories of emergence delirium
circulation/resp (consider before others)
withdrawal
toxic
functional
most common electrolyte disorders contributing to delayed awakening
Na
Mag
Ca
post op pain more severe in
altered CYP2D6
smokers
Most common SE of opiods
bowel dysfunction
med tx for shivering
- demerol
- ketamine
- precedex/clonidine
- hydrocortisone
- zofran
Apfel’s scoring
female, non-smoker, PONV hx/motion sickness, potop opiods. # of factors to risk
- 10-20%
- 40%
- 60%
- 80%
Cardioplegia lowers myocardial temp to what?
8-12 o Celsius
How does desaturated blood leave the patient while on CPB?
From one or two cannulas in RA or SVC/IVC via gravity
Roller pumps on the console of the CPB machine serve what 3 purposes?
Vent the LV
Suction heart
Deliver Cardioplegia
Roller pump, how does it work? How does it prevent RBC trauma?
Flow rate is determined by number of revolutions per minute Provides non pulsatile flow
Subtotal occlusion prevents excessive RBC trauma but not as well as centrifugal pump
Centrifugal pumps are ________ sensitive?
What is a major advantage of these pumps?
Pressure
Unable to pump air, and advantage of less trauma to RBC
What is a major risk if the venous reservoir on CPB becomes empty?
Air embolus
Rate of venous return depends on (3)?
Gravity (ht above reservoir)
Intravascular volume
Proper placement of cannula
Where are volatiles added in the CPB?
The membrane oxygenator
What are some characteristics of the oxygenator?
High surface area and a thin film (mimics pulmonar membrane)
High resistance to flow–needs active pumping of blood
Prone to rupture w/ blood leak or air embolus
Purpose of cardiotomy suction
Salvaged blood from the surgical field to reservoir; can be used for cell saver
Purpose of LV vent? Why is there still blood even on full bypass?
Blood accumulates in the LV from residual pulmonary flow through bronchial arteries or aortic regurg
How often is cardioplegia administered?
Q 15-30 mins
T/F Cardioplegia arrests the heart in diastole.
True
_____ mL cardioplegia to arrest the heart is used, and _____ mL before each distal graft
600 mL
300 mL
T/F the CPB arterial line filter is flushed with 100% O2 for several minutes
False.
It is flushed with 100% CO2 b/c it is 30 times more soluble in water than air
Prime solutions should be iso/hypo/hypertonic?
Isotonic or slightly hypertonic
Goal hematocrit on bypass?
25%
This decreases the viscosity of blood (cold blood is more viscous) and enhances tissue perfusion at low rates
What components are added to priming solution?
Abumin
Mannitol
Heparin 1k to 10k U
Bicarbonate
Blood
Decreased BP from onset of CPB is due to what?
Decrease in SVR from onset of CPB
Decreased blood viscosity
D/c vascular tone d/t:
- dilution of circulation catecholamines
- Temporary hypoxemia
- Low, pH, Ca++ and Mg+ in prime
SVR increases/decreases during hypothermia?
increases
Why do you have a transient d/c in BP after cardioplegia?
It contains nitroglycerin
During rewarming will SVR and MAP increase/decrease? After release of cross clamp?
Increase from 25 to 32 o
Then decline as temp >32o
After release cross clamp, will see decrease in both.
What is goal core body temp on CPB?
25-32 o Celsius
Hemodilution increases O2__________ but decreases O2 ___________?
Increases/improves delivery of O2
Decreases carrying capacity
Hypothermia shifts the oxyhemoglobin curve to the ______?
Left
CPB activates the ________ and ________ cascade systems
Coagulation and fibrinolytic cascade
MI is a rare complication of CPB but ______ and ______ is more common
Injury and cell necrosis
incidence of injury or stroke on CPB?
2-6%
Higher risk for opened chambers such as valve sx
Postoperative Cognitive dysfunction occurence post CPB?
>80%
Renal failure occurence in adults and infants?
1% adults
2-10% in infants
Major GI complications are rare but contribute to low/high mortality rate?
High
With a severe systemic inflammatory response to CPB, how would the following factors appear: HR, SVR, and CO?
Tachycardia
Low SVR
Increased CO
What is the only volatile anesthetic not recommended for patients with CAD?
Desflurane (From Travis’ Cardiac anesthesia notes)
Which side is preferred for radial A line during CABG?
Right, b/c left is occluded by retractor for IMA
What additive is in the ACT tubes?
Celite, aka diatomaeous earth (dirt)
What is average prime volume?
1500 mL
Heparin should be stopped how many hours before surgery?
8
Which artery supplies leads V1-V4?
LAD
Which artery supplies leads I, aVL, V5-V6?
LCX
What is your goal MAC preincision?
0.5-0.7
Heparin dose pre CPB?
300 U/kg
ACT levels, normal, CPB, and off pump bypass?
Normal 105-167
CPB >450
Off pump >300
Heparin MOA?
BInds to Antithrombin III and inhibits thrombin as well as other factors IX-XIIa but mostly Xa
If you give Heparin and ACT does not change, what should you suspect?
ATIII deficiency, may need FFP or synthetic ATIII concentrate
As temp increases, gas solubility ______?
Decreases
As temp decreases, partial pressure of gas in solution _______
decreases
Temperature, solubility, and partial pressure of a gas are related how?
Decreased temp=increased solubility=decreased partial pressure
Increased temp=decreased solubility=increased partial pressure
*Low PP of a gas like CO2 while hypothermic causes vasoconstriction in cerebral vessel*
If Hgb is decreased by 50%, blood flow must ______ to maintain O2 transport
Double
SVR FORMULA
{(MAP-CVP)x80}/CO
CPB effect on Na+K+ pump
Result is low extracellular K+ and higher intracellular K+ until body back to normal metabolic state and temperature
Off Pump Cabg
Temp?
ACT?
Hemodynamics?
Hypothermia avoided-use fluid warmer
ACT >300
Slow HR and keep SBP >100
Low TV and increased RR
Total circulatory arrest
Temp?
Time of procedure?
Temp as low as 15 o Celsius
Keep TCA time <40 mins
2,3 DPG
Increased and Decreased Effects?
Increased 2, 3 DPG: releases O2, decreased affinity
Decreased 2, 3 DPG: doesn’t want to release O2, higher affinity for O2
Bohr Effect
Explains the effect of CO2 concentration on O2 transport.
Occurs at tissue level; increased CO2 level causes d/c affinity for O2 and increased affinity for CO2. “Right shift”
Haldane Effect
Explains effect of O2 concentration on CO2 transport
Occurs at lungs, increased O2 concentration causes d/c affinity for CO2 (wants to get rid of it) and increased affinity for O2 (pick it up to deliver to tissue)
Minute ventilation increases by ___L for each ___mmHg increase in PaCO2
2L; 1 mm Hg
What is the alveolar gas equation?
PAO2= FiO2(PB-PH2O)-(PaCO2/RQ)
PB=760 mmHg
PH20=47 mm Hg
RQ=0.8
Fast administration of Narcan can cause what?
Pulmonary edema
Most common cause of pulmonary edema perioperatively?
Laryngospasm
TF Dysrhythmias in the PACU are typically related to myocardial injury.
False
Common causes include: hypokalemia, hypoxia, hypercarbia, altered acid-base, circulatory instab., pre-existing heart disease
What TOF level is associated with pharyngeal function return?
0.9
Aldrete score of what is adequate for PACU discharge?
9