Lecture 2 Flashcards
Neuromuscular blockades, EEG, evoked potential, Blood transfusion
1
Q
What is the purpose of monitoring the neuromuscular junction?
A
To determine the depth of muscle relaxant block
2
Q
Which nerve is most commonly monitored for recovery?
A
Ulnar nerve
look for thumb mvmt
3
Q
What is the best response to look for when monitoring the ulnar nerve?
A
Movement of the thumb
4
Q
What is the only depolarizing muscle relaxant?
A
Succinylcholine
5
Q
Depolarizing blocks are antagonized by ______.
A
NDMB
6
Q
In non-depolarizing block, there is _______ in twitch height.
A
In non-depolarizing block, there is a decrease in twitch height.
(fade)
7
Q
What characterizes a phase 1 block from succinylcholine?
A
- decrease twitch height
- absence of fade with tetanus
- decrease of all twitches in TOF
- absence of post tetanic potentiation
- (+) fasciculation
8
Q
What are the characteristics of nondepolarizing muscle relaxants?
A
- Decrease twitch height
- Fade with tetanus
- Fade with TOF
- Post tetanic potentiation present
- Absence of fasciculations***
9
Q
What is TOF monitoring used for?
A
To assess neuromuscular block
10
Q
What indicates a 95% block in TOF monitoring?
A
0/4 twitches
11
Q
What indicates a 90% block in TOF monitoring
A
1/4 twitches
12
Q
What indicates a 80% block in TOF monitoring
A
2/4 twitches
13
Q
What indicates a 75% block in TOF monitoring
A
3/4 twitches
14
Q
What indicates a 70-75% block in TOF monitoring?
A
4/4 twitches
15
Q
What is the minimum number of twitches needed to safely reverse a neuromuscular block?
A
2 twitches
16
Q
Describe how to use the TOF and what are you looking for
A
TOF ratio= first and 4th twitch to compare
you always need atleast 2 twitches before you can revere safely
17
Q
What is the significance of a TOF ratio of 4/4?
A
Indicates <75% block
18
Q
What to look for when a pt is recovering from NMB
what is it and how blocked are they still
TOF
VC
Tetanic
Negative inspir
A
o TOF 4/4- <75% block
Need 90% or 0.9 for extubation- need digital readout
o TV- (6 ml/kg) 80% block
o VC- 20ml/Kg– 70% block
o Tetanic 50 Hz- 60% block
Response is a bent fingers towards
o Negative inspiratory force
- 20 to -40 cm H2O = 50% block
High risk of them getting pulmonary edema
Don’t do this- v. old school
o Head lift/hand grasp **
>5 sec – 50% blocked
* Current Evidence
* More reasons why digital readout is best
19
Q
What is Sugammadex used for?
A
Reversal of rocuronium and vecuronium
20
Q
What is the dose of Sugammadex for a TOF of 2/4?
A
2 mg/kg IV
21
Q
What is the onset of Sugammedex
A
2-3 minutes (shorter IRL)
22
Q
What type of monitor is used to assess cerebral function?
A
EEG Monitor
23
Q
What is the purpose of monitoring cerebral function?
A
to detect ischemia
changes in pattern suggest injury
>10 min can mean lasting injury
24
Q
What are some things EEGs are influenced by? (5)
A
deep anesthesia
IV drugs
Hypothermia
Hypotension
Hypocarbia
25
What are the four types of Evoked Potentials (EP)?
and what does an EP monitor?
* Somatic
* Somatosensory EP (SSEP)
* Auditory EP
* Visual EP
evaluates the intactness of neural pathways
26
What is the most common application for Somatosensory Evoked Potentials (SSEP)?
The most common application is to monitor the response from stimulating peripheral nerves like the ulnar or tibial nerve
ie how long does it take for the stimuli to reach the brain
-reflects intactness of pathway
-shows anything that impacts the pathway to the brain
27
What is latency in the context of SSEP monitoring, and why is it important?
what about amplitude
Latency is the time between stimulus and detection. An increase of more than 10% in latency indicates potential injury to the neural pathway.
amplitude- intensity of response – concerned when decreases by >50% (microvolts)
28
how long can the spinal chord tolerate ischemia before permanent injury occurs?
20 minutes
29
What can affect Somatosensory Evoked Potentials?
* Inhalational agents > 0.5 MAC
* Temperature changes
* Hypotension
* surgical factors - harrington rod pressing on nerve, retractor placements
* anemia or hypoxia
30
What are common surgical procedures that may involve SSEP monitoring?
Harrington rod placement (spinal fusion)
Abdominal aortic aneurysm (AAA) repair
Cerebral/thoracic aneurysm surgery
Spinal cord tumor removal
Cervical laminectomy
Carotid endarterectomy
31
How does temperature affect SSEP readings?
Hypothermia: Increases latency and decreases amplitude (1°C change = 1 ms increase in latency).
Hyperthermia: Decreases amplitude and causes loss of SSEPs at 42°C.
Complete EEG suppression can occur at temperatures between 15-18°C.
32
How does hypotension affect SSEPs
A decrease in MAP below 40 mmHg can lead to a decrease in amplitude.
33
How should you manage factors that can affect SSEPS?
Avoid volatile inhalational agents or use at <0.5 MAC
Do not use N2O
Increase blood pressure
Correct anemia or hypovolemia
Increase oxygen tension
Adjust retractor or Harrington rod placement if necessary
34
What anesthesia techniques are recommended for SSEP monitoring?
TIVA (Total Intravenous Anesthesia) is preferred with agents like propofol and remifentanil infusion.
Avoid inhalational agents or keep them <0.5 MAC.
Muscle relaxants are generally safe to use.
35
What is the primary use of Brainstem Auditory Evoked Potentials (BAEP)?
BAEP is primarily used for evaluating the 8th cranial nerve, especially in cases of acoustic neuromas.
- Clicks or tones are delivered to the 8th cranial nerve via a transducer
probs wont see in practice
36
How are Visual Evoked Potentials (VEP) stimulated?
A: VEPs are stimulated by flashing lights via goggles, which assess the pathway from the eye to the brain.
used for pituitary tumor resection
not really seen IRL
37
T/F: VEPS are highly sensitive to inhalational agents
TRUE
highly sensitive- probs will be affected by use
TIVA
38
What anesthesia techniques are recommended for MEP monitoring?
Use TIVA with propofol and remifentanil infusion.
Avoid inhalational agents.
No muscle relaxants should be used, except possibly for intubation (which should wear off before MEP monitoring).
39
What precaution should be taken for patients undergoing MEP monitoring?
Bilateral bite blocks are often used due to reports of patients biting their tongues during the procedure, which could lead to blood loss
40
T/F- it is ok to use muscle relaxants during MEP monitoring
FALSE
Muscle relaxants can block motor responses, rendering MEP monitoring ineffective. However, muscle relaxants can be used for intubation as long as they are reversed by the time MEP monitoring begins.
41
What is the goal of Enhanced Recovery After Surgery (ERAS)?
Enhance postoperative outcomes using a standardized approach to perioperative care
42
What was ERAS created for
improving outcomes for pts having COLON SX
43
What is the definition of Minimal Sedation?
A drug-induced state where patients respond normally to verbal commands
* Responds to verbal command, airway, spontaneous ventilation and cardiac function unaffected
o Relaxed but not apneic
ex- 1 mg Versed- need pt on EKG/Sp02
44
What defines Moderate Sedation?
is a drug-induced depression of consciousness during which patients respond purposefully
may require chin lift
** to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.
Fent and versed
45
What defines deep sedation?
is a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully** following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.
46
MAC: fentanyl
use
dose
analgesic
0.5-2 mcq/kg/IV bolus (usually start 50mcq)
47
MAC midazolam
use
dose
amnestic
1-2 mg IV
ex- obese pts need more versed and less prop so you don't make them apneic and hard to ventilate
| depends on pt and case
48
What monitoring do you need when giving MAC?
BP
EKG
pulse Ox
capnography
precordial stethoscope
temp monitor
maybe BIS
49
MAC propofol
use
dose
hypnotic
20-50 mg/IV bolus
25-75 mcq/kg/min infusion
varies depending on pt- less for the obese and elderly
50
T/F- antibodies cause transfusion rxns
TRUE
51
What is the main purpose of blood group compatibility testing?
To predict & prevent antigen-antibody reactions
52
Percentage of white people who are RH + vs negative
and same for black people
80-85% white are RH + and 15-20 RH-
Black- 92% RH + and 8% Rh-
53
What are the two important blood group antigen systems?
* ABO
* Rh
54
What is the risk of significant transfusion reaction after ABO/Rh testing?
0.2%
55
Fill in the blank: The presence of the D antigen indicates a blood type of _______.
Rh+
56
What is the risk of incompatibility after crossmatching blood?
0.05%
57
What is the risk of incompatibility reaction after a blood transfusion test?
0.06% chance
## Footnote
This indicates a very low risk of incompatibility if the patient has never had a transfusion.
58
What is the purpose of a crossmatch in blood transfusion?
1. Confirms ABO/Rh
2. Detects antibodies to other blood groups
3. Detects antibodies in low titers
## Footnote
A crossmatch mimics transfusion by incubating donor erythrocytes with recipient's plasma.
59
How long does a crossmatch take?
45-60 mins
60
What is the risk of incompatibility in patients who have had a prior transfusion?
1%
61
What are the types of emergency transfusion?
* Type-specific Partially Cross matched
* Type-specific Uncrossmatched
* Type O Negative Uncrossmatched
## Footnote
Type-specific partially cross matched takes less than 10 minutes.
62
What is the volume of 1 unit of whole blood with preservative?
350 ml
63
What does 1 unit of packed red blood cells (PRBC) contain?****
tell me the percentage of Hct too
250 ml PRBC with Hct of 65%
64
Each un it of FFP will increase clotting factor by ____%***
2-3%
65
What is the usual storage temperature for platelets?
20-24℃ for 5 days
66
What is cryoprecipitate high in?
* Factors VIII
* XIII
* von Willebrand factor
* Fibrinogen
67
What is the indication for using cryoprecipitate?
Fibrinogen levels <50-60 mg/dl or active bleeding
68
What is the effect of 1 unit of packed red blood cells (PRBC) on hemoglobin and hematocrit?
Increases Hg by 1 gm/dl and Hct by 2-3%
69
How much will a 5 bag pool of Cryo increase fibrinogen levels?
50 mg/dl
70
2 ways to get platelets
Spun down during single donor whole blood donation- only platelets and plasma collected, red/white cells returned to donor (Apheresis platelets*). Equal to 4-6 pooled units
Pooled random donor platelet concentrates- platelets harvested by centrifuging already donated units of whole blood. Up to 8 units of platelets each from 8 separate donors, then pooled into a single bag. Usual is 4-6 pooled units
71
a platelet count of less than ___________ increases risk of spontaneous bleeding
10-20,000
72
T/F a platelet count of less than 60,000 is associated w/ an increased risk of bleeding during surgery
FALSE- below 50,000
ideally your plt count is above 10,000
73
Each single unit of platelets will increase level by _______________
how much will 6 units of plts increase you by
5,000-10,000/microliter
6 units = 30,000-60,000 /microliter
74
name the 2 types of hemolytic reactions
acute (intravascular) hemolysis
Delayed (extravascular) hemolysis
75
What causes an acute intravascular hemolytic reaction?
ABO incompatibility
(the most common type of transfusion reaction), where the recipient's antibodies attack the transfused RBCs.
midentification of patient or blood specimen often the cause
76
Q: What are the signs and symptoms of acute hemolytic reactions?
Awake: Chills, nausea, chest pain, flank pain
Anesthesia: Fever, tachycardia, hypotension, hemoglobinuria, oozing, DIC, shock, renal failure
77
What causes a delayed hemolytic reaction?
when does it occur
s/s
Delayed hemolysis is often caused by antibodies to non-D antigens of the Rh system and occurs when the patient is re-exposed to the same antigen.
Delayed reactions typically occur 2-21 days after transfusion, with most cases happening 4-8 days post-transfusion.
s/s: malaise, jaundice, fever, decreaseing HCT d/t extravascular destruction of RBCs
78
how do diagnose a delayed hemolytic reaction
coombs test
tx- monitor
79
what do you do if you suspect a transfusion reaction
Treatment:
* Stop transfusion & contact blood bank
* Give Oxygen
* Recheck unit of blood
* Blood/urine specimen from patient
* Foley- check for hemoglobin
* IV fluids
o maintain UO of >75 ml/hr.
Lasix 20-40 mg IV
Mannitol- 12.5-25 gm/IV
Low dose Dopamine
May need platelets/FFP
Sodium bicarbonate
80
tell me about DIC and what does it cause other than death
o Erythrocyin is released from RBC's that activates intrinsic clotting cascade
o Leads to uncontrolled fibrin formation & consumes platelets and factors I, II, V & VII
* Renal failure- acute tubular necrosis (ATN)
o Free hemoglobin collects in distal renal tubules, leading to mechanical obstruction
o Acidic urine increases precipitation
81
name the 3 nonhemolytic reactions you can have from blood and how do youtreat it
febrile- most common- slow transfusion, give tylenol
urticarial-benadryl 50-100 mg IV
-Steroids
anaphylactic-
* Treatment:
o Benadryl 50-100 mg IV
o Epinephrine 0.1-0.5 mg (0.3-0.5 ml of a 1:1000 solution) subcutaneously
o Fluids
o Steroids- hydrocortisone 200 mg/IV
o May need to be intubated
High FIO2, PEEP or CPAP
o Usually with treatment- resolves within 72 hrs.
o 10% mortality
82
What is a common cause of bleeding after a massive blood transfusion?
Coagulopathy due to dilutional thrombocytopenia
83
What are the signs/symptoms of an acute hemolytic reaction?
* Chills
* Nausea
* Chest pain
* Flank pain
* Fever
* Tachycardia
* Hypotension
* Hemoglobinuria
* Oozing
* DIC
* Shock
* Renal failure
84
What characterizes transfusion-related acute lung injury (TRALI)?
Form of noncardiac pulmonary edema occurring within 6 hours of transfusion
85
TRALI s/s
Dyspnea (shortness of breath)
Hypoxia (pulse ox < 90%)
Hypotension
Fever
Bilateral pulmonary edema (fluid accumulation in lungs)
Fluid in ETT (endotracheal tube)
Tachycardia
Absence of circulatory overload (no neck vein distention, normal PCWP, normal heart sounds)
86
how do you treat TRALI
02 and vent (low TV, PEEP 10-15)
resolves within 96 hrs
87
main cause of TRALI and how do we prevent it
HLA antibodies in donor plasma
Blood banks decreased use of plasma from ladies
88
what is TACO
TACO (Transfusion-Associated Circulatory Overload)
A: TACO is a condition caused by the excessive volume of blood transfused, leading to pulmonary edema and decreased functional residual capacity (FRC).
89
TACO s/s
think she overloaded
Hypoxia
Increased CVP (central venous pressure)
Tachycardia
Shortness of breath (SOB)
Hypertension
Hypervolemia (fluid overload)
Left ventricular (LV) dysfunction
Increased pulmonary artery occlusion pressure
Pulmonary edema seen on chest X-ray
90
What is the treatment for transfusion-associated circulatory overload (TACO)?
* Oxygen
* Support ventilation
* Diuretics
91
T/F- TRALI has an elevated WBC count
FALSE- it's DECREASED
main way to differentiate TACO and TRALI
TACO has no affected WBC count
92
What is graft vs. host disease (GVHD)?
Leukocytes in donor blood attack recipient's bone marrow
* Recipient unable to reject the donor leukocytes because of immunodeficiency or severe immunosuppression
93
how do you diagnoses PTP and what is the treatment
* Patient develops an alloantibody in response to platelet antigens in the transfused blood, which then causes destruction of the patient's platelets-
* See thrombocytopenia 5-10 days after transfusion (usually 7 days), usually associated with PRBC
* Platelet counts <10,000
* Platelet transfusion is of little help
* Need plasmapheresis & IgG IV
94
What is the most common abnormality after a blood transfusion?
Metabolic alkalosis
95
3rd leading cause of transfusion mortality
and what's the treatment
bacteria in blood from collection or processing
Staph/citrobactor
* Treatment-
o stop transfusion
o support CV and respiratory systems
o blood cultures
o broad spectrum antibiotics
o Administer blood under 4 hours
96
Hepatitis B
HIV
Hepatitis C
CMV
put these in order from most to least common in terms of risk of infection after a blood transfusion
(most common) CMV > Hep B > Hep C > HIV (rarest)
97
What is the anticoagulant preservative used in stored blood?
Citrate phosphate dextrose adenine (CPDA-1)
citrate-anticoagulant
phosphate- buffer to combat acidosis
dextrose- RBC energy source
Adenine- allows RBC to resynthesize ATP to extend shelf life from 21-35 days
98
What is the effect of hypothermia during massive transfusion?
Increases morbidity & mortality
Peripheral vasoconstriction
Metabolic acidosis
Impaired Hg/Oxygen delivery
o Decreased cardiac output
o Arrhythmias
o Impaired coagulation
o Every 1 degree drop in temperature will decrease clotting factors 10%
99
What can citrate toxicity lead to?
* Hypocalcemia
* Hypotension
* Increased CVP
* Prolonged QT
* Decreased Mg
* Decreased cardiac output
100
what is the purpose of Citrate in stored blood
anticoagulant
101
why is blood stored at 1-6C
slows the rate of glycolysis
102
how long can you store blood with CPDA-1 in it
35 Days
103
shelf life of blood with As-1 in it
42 days!!
104
s/s of citrate toxicity
hypocalcemia,
hypotension,
increased CVP,
prolonged QT,
decreased Mg,
decreased cardiac output
105
who gets citrate toxicity?
those who get lots of blood- its from Ca binding in pt from citrate in tranfused blood
MTP
106
What is the usual potassium concentration in stored blood?
4 meq/unit
107
What is the purpose of preoperative donation in autologous blood procedures?
Decreased chance of infection/transfusion reaction
108
Preop donation of autologous blood
o 4-5 weeks prior to procedure
o Hct must be above 34% or Hg greater than 11****
o 1 week between donations
o Fe supplement & Erythropoietin therapy- usually can donate 3-4 units
o Decreased chance of infection/transfusion reaction
109
What is the technique for acute normovolemic hemodilution (ANH)?
Blood taken from patient replaced with crystalloid and colloid
110
What is the minimum time interval required between blood donations?
1 week
111
What is the typical number of blood units that can be donated when undergoing Fe supplement & Erythropoietin therapy?
3-4 units
112
What is the purpose of Acute Normovolemic Hemodilution (ANH)?
Decrease concentration of RBC and RBC loss during surgical procedures
113
What should the hematocrit (Hct) level be maintained at during ANH?
21-28%***
114
What is the blood replacement technique used in ANH?
Blood taken from patient and replaced with crystalloid (3/1 ml) and colloid (1/1 ml)
115
How long can blood be kept as whole blood at room temperature during ANH?
8 hours
116
What is the requirement for intraoperative/postoperative blood salvage (Cell Saver)?
Need 1000 ml blood loss or greater
117
What happens to the blood aspirated during intraoperative/postoperative blood salvage?
Filtered and washed, then given back as **PRBC’s**
118
What are the contraindications for using intraoperative/postoperative blood salvage?
Contaminated wound, sickle cell disease, urine/fecal contamination, malignant cells
119
What is a donor directed blood donation?
Family/Friends donate
120
How long does it take to process donor directed blood donations?
7 days
121
What is the purpose of antifibrinolytics in pharmacologic therapy?
Control postoperative bleeding
122
What is the function of Aminocaproic acid (Amicar)?
Control postoperative bleeding
123
What is the role of Desmopressin in pharmacologic therapy?
For platelet dysfunction with adequate count
124
What does Desmopressin increase in the blood?
von Willebrand’s factor & factor VIII
125
What is the intravenous peak effect time for Desmopressin?
15-30 minutes
126
What are some anesthesia techniques that can help decrease blood loss?
Maintain normothermia, LFA, Controlled hypotension, Maintain adequate fluid volume
127
what are the facial movements to look for with the nerve stimulator
| Two Zebras Bit My Cock (Cornea?)
Temporal
Zygomatic
Buccal
Mandibular
Cochlear cervical
128
what augments Succ?
Cholinesterase inhibitors
cirrhosis
being preggo
infants
atypical enzymes
129
ASA NPO guidelines:
clear liquids-2 hours
breast milk-4 hours
infant formula, non human milk, light meal- 6 hours
heavy meal (fries fatty foods and meats)- 8 hours
130
