Section 3: General Principles of Anesthesia Flashcards
Define “MET:’
A MET is a Metabolic EquivalenT and is defined as the amount of oxygen
consumed while sitting at rest
MET are used to
evaluate functional capacity
and reserve.
1 MET equal
equal to 3.5 mL 02/kg/min
Metabolic equivalents (METs) range from
1 to I2 (in whole numbers).
MET for eating, working at a computer, or dressing.
One metabolic equivalent ( 1 MET) correlates
METs: walking down stairs, walking in your house, or cooking.
2 METS
MET for walking one or two blocks on level ground.
3 METs correlates
MET: Raking leaves or gardening is equivalent to
4 METs.
METs for climbing one flight of stairs, bicycling or dancing. Six metabolic equivalents ( 6 METs) is .
Five metabolic equivalents (5 METs}
METS playing golf or carrying golf clubs
6 METs
Playing singles tennis.
7 METs correlates to
Rapidly climbing stairs or slowly jogging is equivalent to
8 METS
Correlates with jumping rope slowly or
moderate cycling.
Nine metabolic equivalents (9 METs
Swimming quickly, running or jogging briskly.
10 METs
Cross country skiing or playing full court basketball.
11 METs
Running rapidly for moderate to long distances is equivalent to
12 METs
Define the physical status index "ASA PS class 6."
Declared brain-dead patient whose organs are being removed for donor purposes is defined as ASA PS class 6
How much dextrose is in a 1-liter bag of
DSW? What is the dextrose concentration
{mg/mL)?
A one-liter (I L) bag of DSW contains 50 grams of dextrose, a concentration
of 50 mg/ml
In addition to sodium {140 mEq/L) and
potassium (5 mEq/L), what three electrolytes does Normosol-R contain?
In addition to physiologic concentrations of sodium and potassium, Normosol-R contains magnesium (3 mEq/L), acetate (27 mEq/L) andgluconate (23 mEq/L).
List 4 reasons why dextrans are of limited
use nowadays.
Dextran toxicities include:
(I) Antithrombotic effects, particularly inhibition of platelet aggregation;
(2) interference with blood cross-matching-dextrans coat RBC membranes;
(3) anaphylactic and anaphylactoid reactions; and
(4) renal dysfunction resulting from osmotic nephrosis.
Dextrans are relatively ___but what limits their use?
inexpensive (dextrans are produced by bacteria), but their range of toxicities limits their use.
Which blood components are found in
packed red blood cells (PRBC)?
Packed red blood cells (PRBC) contains red blood cells in anticoagulated
plasma.
In PRBCs, Most plasma is removed
(by centrifugation) and is replaced by pre·
servative, most commonly citrate phosphate dextrose adenine-I (CPDA-1).
The addition of adenine to packed red blood cells (PRBC) stored in CPD
extends the storage time from 21 days to ____days.
The addition of adenine to citrate phosphate dextrose (CPD) solution
allows RBCs to resynthesize adenosine triphosphate (ATP}, which extends
the storage time from 21 to 35 days.
How long can RBCs or WHOLE blood can be stored _______when stored in ___
As a result, RBCs or whole blood can
be stored for 35 days when stored in CPDA-1.
Name three preservatives that extend the storage time of packed red blood cells (PRBC) from 3S days to 42 days.
The shelf life of packed red blood cells {PRBC) can be extended to 42 days when AS- I (Adsol). AS-3 (Nutricel), or AS-S (Optisol) is used
Extending blood storage to 42 days is a mixed blessing. Describe the bio-chemical alterations of stored blood.
During storage, RBCs metabolize glucose to lactate, hydrogen ions mutate, and plasma pH decreases. The storage temperatures of 1 °C to 6 °C depress the sodium-potassium pump, thus RBCs lose K+ and gain Na+. Some RBCs undergo lysis, resulting in increased plasma Hb levels. Progressive decreases in ATP and 2,3-diphosphoglycerate (2,3-DPG) occurduring storage and factors V and VII (most labile factors) are decreased as
well. Summary of plasma changes in stored blood: fewer RBCs in an acidic,
hyponatremic, hyperkalemic, hypoglycemic plasma, with increased free hemoglobin and decreased 2,3-DPG.
Which blood components are present in frozen plasma (FFP)?
Fresh-frozen plasma contains ALL clotting factors, naturally occurring inhibitors of coagulation, and antithrombin (formerly antithrombin III). FFP is devoid of red blood cells and platelets
Which blood components are present in cryoprecipitate?
Cryoprecipitate is a protein fraction collected from the top of thawing FFP and therefore contains concentrated factors I, VIII, vWF, XIII, and fibronectin
Which blood product contains the greatest concentration of fibrinogen (factor I)?
Cryoprecipitate contains more fibrinogen per volume than fresh-frozen plasma, specifically l S g/L in cryo compared to 2.S g/L in FFP ( 6x more fibrinogen in cryo).
State the threshold for fibrinogen replacement
The traditional threshold for fibrinogen replacement is fibrinogen levels less than 80 to 100 mg/dL.
How many bags of cryoprecipitate constitute a single dose?
A single dose- 5 pooled bags of cryoprecipitate
What is the expected fibrinogen increase following one dose of cryoprecipitate
typically raises the fibrinogen concentration by 5O mg/dL
UPTDATE THIS: According the the AS/\s 2006 updated practice guidelines, at what hemoglobin level is RBC transfusion rarely indicated?
rarely indicated when the Hgb concentration is more than 10g/dL
At what Hgb level is RBC transfusion always indicated?
Almost always indicated when is less than 6g/dL , especially when anemia is acute
According to the ASA 2006 updated practice guidelines, what factor justifies RBC transfusion when hemoglobin levels are intermediate (6- 10 mg/dL)?
should be based on the patients risk for complications of inadequate oxygenation.
List four (4) variations of head-elevated surgical positions.
Four variations of head-elevated positions are: (l) sitting, including lounge
chair and beach chair variation; (2) supine- tilted head up; (3) lateral-tilted
head up, also called the .. park bench” position; and, (4) prone- tilted
head up.
Is the most feared complication of head up surgical positions, as you know.
Venous air embolism
In head up positions may compromise the airway.
Edema of the face, neck, and tongue
What is the cause of edema in these areas in a head up position?
Edema of the face, neck, and tongue in head up positions, including severe
postoperative macroglossia, is purportedly due to venous and lymphatic obstruction caused by prolonged, marked neck flexion.
What precautions should be taken to
minimize the occurrence of face, neck,
and tongue edema in the head up
positions?
Avoid placing the patients chin against the chest- do not force the chin into the suprasternal notch- and use an oral airway to protect the endotracheal tube.
What nerve injury may occur from a
sternal retractor?
Spreading of the sternal retractor during cardiac surgery causes the clavicle
to move posteriorly and the first rib to move upward thus pinching the brachial
plexus between the two bones.
Dissection of the internal mammary artery requires wide, asymmetric chest retraction and may lead to
brachial plexus neuropathy,
Brachial plexus injury from sternal rectractor most often manifest as
sensory deficit in the distribution of the ulnar nerve
Describe the method and rationale for
denitrogenation (pre-oxygenation) of
the airway.
With a tight mask seal, provide 100% oxygen at a flow rate high enough
to prevent rebreathing ( 10-12 L/min). Slight head up position has been
recommended. Denitrogenation allows the patient’s functional residual capacity (FRC) to be filled with approximately 90% oxygen, thus lengthening the apnea time without desaturation and improving safety.
How is an oropharyngeal airway sized?
Measure from the corner of a patient’s mouth to the angle of the jaw or earlobe.
What problems may be seen with their
usage?
Poorly sized oral airway devices can actually worsen the obstruction. Other complications include lingual nerve palsy and damage to teeth.
Name 4 types of supraglottic airways.
Laryngeal mask airways (i.e. LMA classic, LMS ProSeal, LMA Supreme),
Perilaryngeal sealers (air-Q SP),
Cuffless preshaped sealers (i-gel), and •
Cuffed pharyngeal sealers
Describe the advantages of supraglottic airways.
Advantages include the ease and speed of placement, reduced anesthetic requirements and the resulting hemodynamic stability, less airway manipulation, less dental trauma, less coughing on emergence, and less risk of bronchospasm.
Describe the disadvantages of supraglottic airways.
Ineffective ventilation when higher airway pressures are required, no protection from laryngospasm, and no protection from gastric aspiration, though newer models of SGA devices have been designed to reduce this risk.
Describe the benefits of alternative LMs,
including the i-gel and air-Q.
The i-gel is a cuffless LM. Its advantages include a simplified insertion and easy positioning. The air-Q device has a self-pressurized cuff that eliminates overinflation. Both alternative supraglottic devices reduce the incidence of sore throat.
What is the Fasttrach LMA?
The Fastrach LMA, or intubating LMA (ILMA), was specifically designed
for use in difficult airway situations.
The primary distinguishing features of
the Fastrach LMA are:
[1} an anatomically curved rigid airway tube;
(2} anintegrated guiding handle;
(3} an epiglottic elevating bar; and,
(4} a guiding ramp built into the floor of the mask aperture
What advantage does the epiglottic
elevating bar afford the ILMA (Fastrach
LMA)
The 2 bars at the aperture of the LMA classic are replaced in the ILMA by
a single, moveable epiglottic elevating bar that pushes the epiglottis out of the way allowing smooth and unobstructed passage of the endotracheal
tube as it emerges from the distal end of the ILMA’s metal shaft.
What are the advantages of the integrated guiding handle on the Fastrach LMA
{ILMA)?
The integrated handle at the proximal end of the barrel of a Fastrach LMA
is used for insertion, repositioning, and removal. The position of the device
can be optimized by lateral and anterior-posterior manipulation by using
the integrated handle, an action called the Chandy maneuver
What is the “RODS” mnemonic?
"RODS" is used to identify difficult extraglottic device situation. Restricted mouth opening Obstruction Distorted airway or disrupted airway Stiff lung or stiff cervical spine
What is the most common adverse effect
reported with the use of the laryngeal
mask airway (LMA)?
Sore throat with an incidence of 10% is the most common adverse effect of
using an LMA.
The sore throat with LMA is most often related to
over inflation of the cuff.
You decide a laryngeal mask airway (LMA) is appropriate for the airway management of the 9-kg patient, but a 1.5 LMA is not available; will you use a size l or a size 2 LMA?
LMA size selection is critical to its successful use, and to the avoidance of minor as well as more significant complications. The manufacturer recommends that the clinician choose the largestsize that will fit comfortably in the oral cavity, and then inflate to the minimum pressure that allows ventilation to 20 cm H10 without an air leak. Accordingly, a size 2 LMA classic is appropriate for the 9-kg patient
Pediatric LMA sizing is based on
weight.
What are the approximate weights for LMA sizes 1 through 3? < 5 Kg
Size 1
What are the approximate weights for LMA sizes 1 through 3? Weight 10-20
Size 2
What are the approximate weights for LMA sizes 1 through 3?Weight 5-10 kg
Size 1.5
What are the approximate weights for LMA sizes 1 through 3? Weight 20-30 kg
Size 2.5
What are the approximate weights for LMA sizes 1 through 3? Weight 30-50
Size 3
List indications for using an Esophageal-
Tracheal Combitube {ETC).
Indications for an ETC include supraglottic obstruction, morbid obesity, vomiting, regurgitation, massive airway or upper gastrointestinal bleeding, and acute bronchospasm.
The ETC requires
minimal training for proper placement.
Airway reflexes should not be intact during
ETC use.
Describe the functions of the Air-Q
perilaryngeal tube?
The Air-Q is an SGA device. It acts as a conduit for blind, or more likely,
fiberoptic placement of an ETT.
How is the King LT positioned for proper
ventilation
When properly placed, the esophageal cuff is seated in the esophagus, with the opening positioned over the larynx. Both cuffs are then inflated simultaneously by injecting air in just one inflation port. This will provide a sealed method for ventilation.
The King laryngeal tube has a
small esophageal cuff and a larger hypopharyngeal cuff, with an opening between the 2 cuffs
With the king LT If ventilation is inadequate, the device is
likely inserted too deep
Describe removal of a supraglottic
device.
Properly timing the removal of an SGA is critical. The patient should either be deeply anesthetized, or awake enough to open mouth on command. Removing
the device during the excitation phase of emergence can result in Iaryngospasm. The cuff remains inflated to lessen the amount of secretions left behind and dropping into the airway.
Describe the passing of the ETT and the
depth of its insertion in the adult.
The tracheal tube should be observed while passing through the vocal cords and then advanced 2 cm past the glottic opening. This should result in placement halfway between the vocal cords and the carina, with an approximate depth of 21-23 cm at the teeth.
Describe the Cormack- Lehane laryngeal
view scoring system. Grade I
Grade l- view of entire glottic opening;
Describe the Cormack- Lehane laryngeal
view scoring system. Grade II
Grade 2- view of only posterior glottis opening;
Describe the Cormack- Lehane laryngeal
view scoring system. Grade III
Grade 3- view of only the tip of the epiglottis;
Describe the Cormack- Lehane laryngeal
view scoring system. Grade IV
Grade 4- view of only the soft palate. (
What is BURP?
A “BURP” is a maneuver to place backward-upward-rightward pressure
on the thyroid cartridge to improve laryngeal view during direct laryngoscopy.
Describe the Mallampati I-IV grading system? Class I
faucial pillars, uvula, soft palate are visible;
PUSH
Describe the Mallampati I-IV grading system? Class II
base of uvula, soft palate are visible;
Describe the Mallampati I-IV grading system? Class III
soft palate and hard palate are visible;
Describe the Mallampati I-IV grading system? Class IV
only hard palate is visible.
What is the “LEMON” mnemonic?
Look externally;
Evaluate 3-3-2 rule: mouth opening at least 3 finger-breadths (4 cm}, distance
from hyoid bone to chin 3 cm (2 finger-breadths). and distance from
the thyroid notch and floor of the mandible (top of the neck) should be at
least 2 finger-breadths;
Mallampati;
Obstruction;
Neck mobility.
The LEMON mnemonic is used to
identify a difficult airway.
Identify nine (9) anatomical Characteristics that can indicate a potentially difficult intubation?
l) Short, muscular neck,
(2) short thyromental distance,
(3) Mallampati Ill or IV, (4) receding mandible, (5) protruding maxillary incisors, (6)prominent overbite, (7) limited temporomandibu-lar joint mobility, and8) limited cervical spine mobility, and a (9) high arched palate are anatomical characteristics that an indicate a potentially difficult intubation
State seven (7) risk factors for difficult mask ventilation.
Seven risk factors for difficult mask ventilation are:
l) presence of a beard
2) body mass index >30 kg/m2,
(3) lack of teeth (edentulous),
(4) age > 55 years, and
(5) Obstructive Sleep Apnea or a history of snoring,
(6) male gender, (7) Mallampati III or IV.
The MOANS mnemonic is
used to identify difficult mask ventilation: Mask seal Obstruction or Obesity, Age> 55 years, No teeth, Stiff lungs
What are the advantages cricoid pressure?
Cricoid pressure (the Sellick maneuver), when properly applied, has been used to prevent aspiration in emergency airway management and rapid sequence induction (RSI).Occlusion of the esophagus is created with gentle pressure placed on the cricoid cartridge.
What are the disadvanages of cricoid pressure?
In recent years, studies have shown this technique may potentially worsen the laryngoscopic view without preventing aspiration. There is little risk to the use of cricoid pressure and it can be easily discontinued, therefore it is still used by many providers.
What are the advantages of indirect
(video) laryngoscopy over direct laryngoscopy
vastly improved visualization, fast learning curve, magnification of the airway, external video monitor allowing others to see airway, recording capabilities for education and research.
What disadvantages have been encountered when using a video laryngoscope
Indirect (video) laryngoscopes have improved visualization of the glottic
structures, but this does not always lead to successful intubation. Directing
the tube into the trachea can still be difficult. Blood and secretions can also
obscure the camera. Video laryngoscopes cost far more than conventional
laryngoscope
How can we prevent water and heat loss
from an intubated patient? Why is this
important
Patients with an airway device {ETT or SGA} that bypasses this area, lose this function, resulting in inhalation of a dry, cool gas that decreases mucociliary function. Secretions can become dry and in prolonged cases can lead to partial or complete obstruction of the ETT. Therefore, intraoperative heat and moisture loss from the airway can be prevented by the use of a disposable heat-moisture exchange (HME)
The upper respiratory tract is the primary
moisture and heat exchanger for
the airway.
After induction, you are unable to intubate
and unable to ventilate with 2 hand
mask ventilation. What is your next
immediate step?
Place an LMA and regain ventilation
Describe positioning the obese patient
for airway management.
Using a wedge-shaped lift is recommended when positioning the obese patient for intubation. The wedge pillow moves the patient’s chest away from the laryngoscope handle. helps to align the external auditory meatus with
the sternal notch (EAM-SN position), and allows gravity to pull the excess weight away from the airway
What is considered the primary anesthetic
for awake airway management
Topicalization of the airway is considered the primary anesthetic for awake
airway management.
With AWAKE Airway management, The focus should be on anesthetizing If
the base of the tongue, the oropharynx, hypopharynx, and laryngeal structures. Anesthesia of the oral cavity is unnecessary.
If topicalization of the airway mucosa
is insufficient, then the supplemental use of
nerve blocks may be indicated
After anesthetizing the nasal cavity,
using nasal pledgets soaked in 4%
cocaine, a 34-F nasal airway coated in
4% viscous lidocaine is inserted into the
nasal cavity. Besides topicalization of the
airway, what is accomplished by using
this technique?
Dilation of the nasal cavity, prediction of the angle of insertion of ETT, and prediction of the easy passage of a 7.0 endotracheal tube (due to the 34-Fnasal airway}. [
Nasal cavity anesthesized with
Nasal pledgets soaked in 4% cocaine, a 34F nasal airway coated with 4% viscous lidocaine.
Block of which nerve abolishes the gag
reflex and decreases the hemodynamic
response to laryngoscopy?
The glossopharyngeal (GPN) block is highly effective in abolishing the gag
reflex and decreasing the hemodynamic response to laryngoscopy, including
awake laryngoscopy
Explain the anterior approach to the
glossopharyngeal nerve block
After topicalization of the posterior pharynx, the patient opens his or her
mouth and protrudes the tongue forward. The anesthetist then displaces the
tongue to the opposite side with a tongue blade, resulting in the formation of a
gutter. Using a 23- or 25-gauge spinal needle, insert the needle approximately
0.25 to 0.5 cm, into the space where the gutter meets the base of the palatoglossal
arch and aspirate for air… After
correct positioning, I to 2 mL of2% lidocaine is injected, and the block is then
repeated on the opposite side
During the GPN block If air is obtained on aspiration, WHat should be done?
the needle has been placed too deeply and should be withdrawn until no air is aspirated
During the GPN block If blood is obtained on aspiration, WHat should be done?
If blood is
obtained, the needle must be withdrawn and repositioned more medially
The anterior approach to the glossopharyngeal block is good because it
isolates the lingual branch of the glossopharyngeal nerve.
It is better tolerated by the patient and involves injecting local anesthetic at the base of the anterior tonsillar pillar (palatoglossal arch).
Glossopharyngeal nerve block
Describe the approach to the superior
laryngeal nerve block.
Palpate the superior notch of the thyroid cartilage and locate (mark) the position 2 cm laterally on each side. At this mark on each side, insert a 25g needle, in a posterior and cephalad direction, 1- l.5 cm deep. Inject 2 mL of2% lidocaine. Always monitor for signs oflocal anesthetic toxicity.
Describe the approach to the transtracheal
nerve block.
Identify the CTM (cricothyroid membrane). Using a Sec syringe with a 20g-22g needle, insert posteriorly and slightly caudally, until air is aspirated.
Inject 4 mL of2% or 4% lidocaine. Always monitor for signs of local anesthetic toxicity
What are the disadvantages to the superior
laryngeal nerve block?
Disadvantages to the superior laryngeal nerve block are: (1) Laryngeal
edema and airway obstruction from accidental injection into the thyroid
cartilage. (2) Increased risk of aspiration. (3) Rupture of ETT cuff in a patient already intubated. (4) Hypotension and bradycardia. (5) Hematoma formation.
List (6) supportive criteria for awake
tracheal extubation.
Follows commands, intact gag reflex, oropharynx clear of secretions, minimal end-tidal percent of inhaled agent, and adequate pain control and • respiratory rate, adequate neuromuscular reversal indicated by TV >6ml/ kg. sustained tetanic contraction and T1-T. ratio >0.7, and sustained head lift and hand grasp.
What three (3) criteria should be met
before proceeding with a deep extuba·
tion?
Deep extubation is acceptable if there was: ( l) Easy mask ventilation after
induction; (2) non-airway surgery; and, (3) an empty stomach. [
List (5) systemic complications of tracheal
extubation
Five systemic complications assocdiated with trachel extubation are: Hypertension, Increased ICP increased intraocular pressure wound dehiscence, and increased pulmonary artery pressure
What is the mechanism of action of
sugammadex?
Sugammadex, a cydodextrin, is a hollow structure molecule, capable of trapping
other molecules within its core. It causes reversal by encapsulation and has no
effect on acetylcholinesterases or on any receptor system in the body. When used
in appropriated doses, sugammadex can reverse any depth of neuromuscular
blockade. It binds tightly with rocuronium, and vecuronium, and to a lesser extent
pancuronium.
Does sugammadex work on a receptor
NO.
How does the use of sugammadex impact
airway management
Sugammadex is useful as an alternative reversal agent, when profound
relaxation with rocuronium, or vecuronium, is still in effect at the end of •
the case. Cases of re-paralysis have been noted when insufficient doses of
sugammadex are given
What is routinely found in a pre-packaged
cricothyrotomy kit?
Most universal cricothyrotomy kits contain the tools to perform either an open
surgical or percutaneous cricothyrotomy via Seldinger technique. Both techniques
are utilized in a CICV (can’t intubate, can’t ventilate) scenario. Both are invasive
emergency airways. The set usually includes a tracheostomy tube, dilator, scalpel, syringe, introducer needle, firm guide wire, tracheal hook, forceps and ties to secure the device.
Best way to know what is pre-packaged cricothyrotomy kit?
Familiarize yourself with the kit available in your institution.
What size scalpel is preferred when
performing an open surgical cricothyrotomy?
A #20 scalpel will produce an opening wide enough to insert a narrow tube
into the trachea without the need for extending the surgical incision. Its
length is long enough to enter the trachea, but unlikely to damage posterior
wall.
This technique is often the fastest, and is employed when speed is
needed, or other techniques are unavailable
open surgical cricothyrotomy
Why is surgical cricothyrotomy contraindicated in the younger pediatric
population? What is used instead?
Surgical cricothyrotomy contraindicated in the younger pediatric population because
the cricoid cartilage is the narrowest portion of the airway in children under
6, and the thyroid gland also typically extends over the cricothyroid membrane
(CTM). Needle cricothyrotomy with transtracheal jet ventilation is indicated.
Several companies make preformed pediatric ventilation catheters similar to an
intravenous catheter. These preformed catheters have the advantage of a built in
15-mm adapter that works with standard bag ventilation devices, and a Luer-lok •
connecter for jet ventilation.
What is lingual tonsillar hyperplasia?
In lingual tonsil hyperplasia, the vallecula is filled with an overgrowth of
hyperplastic lymphoid tissue, potentially resulting in an unanticipated
difficult airway
In a patient with atlantoaxial subluxation,
displacement of what anatomical
structure can cause compression of the
spinal cord and/or vertebral arteries
Movement of the head and neck displaces the odontoid process causing
damage to the spinal cord and compression of the vertebral arteries. Careful preoperative assessment of neck mobility is recommended. Minimizing
movement of the head and neck during laryngoscopy is indicated.
During tracheotomy surgery, a fire develops at the surgical site. What is your
course of action?
Immediately remove the tracheal tube and
Stop the flow of all airway gasses
Remove sponges and other flammable
materials from the airway.
Pour saline to extinguish the fire. Re-establish
Ventilation and assess for airway injury. Consider bronchoscopy to assess
for airway damage and tracheal tube fragments possibly left behind. In cases of
severely difficult airway where removal of TT will result in permanent and deadly loss of the airway, clinical judgment for best possible outcome should be used in deciding to remove the TT.
Damage of what nerve can also cause
airway issues in the post-thyroidectomy
patient?
Acute bilateral recurrent laryngeal nerve injury causes coughing, stridor,
airway obstruction, and respiratory distress.
What is the action of dexmedetomidine?
Dexmedetomidine is a potent, short acting, alpha-2 adrenergic agonist. A
predominance of alpha-2 receptors are located in the pontine locus ceruleus of
the brainstem, an area that mediates vigilance, memory. analgesia, and arousal.
ment.
Describe its use regarding airway
management.
Dexmedetomidine inhibits this nucleus, providing analgesia and sedation without
depression of ventilation and therefore has been useful in difficult airway manage·
Precedex, Concomitant use with drugs that work on GABA
(versed, propofol) can causea paradoxical agitation.
In what clinical situations are fiberoptic
intubation useful
(1) An·atomic abnormalities of the upper airway (restricted mouth opening, small
mandible, morbidly obese)
(2) Cervical spine immobilization (trauma,
severely decreased ROM, cervical fusion ); (3) Failed intubation attempts
where ventilation is possible (FOi through LMA or mask as a conduit);
(4)
Anticipated difficult airway (tumors, abscess, hematoma);
(5) Placement of double lumen ETT; and,
(6} Visualizing the airway below the cords.
After the induction of a patient scheduled for laparoscopic cholecystectomy, direct laryngoscopy has failed times 3. Mask ventilation with 100% 02 is adequately achieved. What is your next course of action
Due to adequate facemask ventilation, the non-emergent difficult ajrway
pathway should be used. This includes maintaining ventilation while using
alternative techniques at intubation. ILMA, Fiberoptic through LMA,
Video laryngoscope, Gum elastic bougie, retrograde wire intubation,
lighted stylet. If unable to secure the airway consider cancelling the case or
awakening the patient
What is the “SHORT” mnemonic?
"SHORT" is a mnemonic used to identify difficult cricothryotomy. Surgical obstruction Hematoma/abscess Obesity Radiation distortion Tumors.
Define sleep apnea.
Sleep apnea is the cessation of breathing for more than 10 seconds during
sleep. Obese patients with sleep apnea may have partial or complete
obstruction of the upper airway during sleep.
What are the symptoms and physiologic changes associated with it?
Symptoms include frequent
arousals during sleep, snoring, impaired concentration, memory issues,
headaches.
Physiologic changes with OSA
Physiologic changes include hypoxemia, hypercapnia, pulmonary HTN, and systemic vasoconstriction
What is the “gold standard” diagnostic
test for obstructive sleep apnea {OSA)?
Overnight Polysomnography is the gold standard for diagnosis of obstructive
sleep apnea {OSA).
OSA due to inconvenience, and expense, many patients do not have a formal OSA diagnosis. Clinical diagnostic
indicators include
Witnessed apnea during sleep Neck circumference >equal to 16in BMI >35 Hyperinsulinemia Elevated glycolsylated hemoglobin.
What is Pickwickian syndrome?
Pickwickian syndrome results from long term OSA. Physiologic changes
from airway obstruction and chronic hypoventilation include hypoxemia,
hypercapnia, systemic vasoconstriction. and pulmonary HTN
What are the post-operative airway considerations in a patient with Pickwickian syndrome?
These patients are highly sensitive to the respiratory depressant effects
of anesthesia. Continuous positive airway pressure {CPAP) placed in the immediate after extubation {before transfer to PACU) have shown greater lung function 24 hours postoperatively
Pickwickian syndrome Pain and regional
Continuous regional anesthesia is preferred over opioids.
Pickwickian syndrome and Benzodiazepines
Benzodiazepines have a greater effect on pharyngeal muscle tone and can
contribute significantly to post-extubation airway obstruction, and therefore
are generally avoided
List otolaryngologic airway disorders
that can present difficult airway management for the anesthetist.
Otolaryngologic airway disorders that can present airway management
challenges are: (l) airway infections; (2) airway tumors; (3) angioedema;
and, (4) other pathologic conditions, such as congenital malformations,
recurrent laryngeal nerve injury, facial trauma, and. OSA.
What is the result of blocking each of the
nerve fiber types : B fibers
B fibers- venodilation with hypotension;
What is the result of blocking A-delta fibers-
loss of pain and temperature;
What is the result of blocking A gamma
loss of muscle tone;
What is the result of blocking A·alpha
loss of motor function and proprioception (position sense)
What is the result of blocking C fibers
loss of pain and temperature
For epidural anesthesia, clinically useful doses of local anesthetics are based on volumes that permit an even filling of the anterior and posterior epidural spaces at the level of insertion.
The suggested volume of local anesthetic for epidural anesthesia at cervical and thoracic level is 0. 7-1 mL per spinal segment to be anesthetized.
Which four local anesthetics (and concentration) provide potent sensory block analgesia and minimal motor block when administered epidurally?
Bupivacaine (0.5%), ropivacaine (0.5%), levobupivacaine (0.5%). and plain lidocaine (2%) provide potent sensory analgesia and minimal motor blockade when administered epidurally
How much local anesthetic is required
for a fascia iliaca block?
Since the fascia iliaca block depends on the spread of local anesthetic along
a connective tissue plane, it is a large-volume block. Approximately 30-40
ml of injectate is necessary to accomplish a fascia iliaca block (0.5-1 ml/ kg for pediatric patients).
block depends on the spread of local anesthetic alonga connective tissue plane, it is a large-volume block.
Since the fascia iliaca
Describe the anatomy of the fascia iliac
block.
The three distal nerves of the lumbar plexus, the femoral, lateral femoral
cutaneous, and obturator nerves, all emerge from the psoas muscle and
run along the inner surface of the fascia iliaca. A fascia iliaca compartment
block delivers local anesthetic between the fascia iliaca and iliacus muscles
where it spreads to bathe the three nerves
What are the three distal nerves of the lumbar plexus? LFO
LFO
The femoral, lateral femoral cutaneous, and obturator nerves
The three distal nerves of the lumbar plexus, the femoral, lateral femoral
cutaneous, and obturator nerves, all emerge from the
psoas muscle
What are the indications for a fascia
iliaca block?
The fascia iliaca block provides analgesia of the femoral, lateral femoral cutaneous,
and obturator nerves and therefore is useful for anterior thigh and knee surgery, and to provide analgesia following hip and knee procedures. The fascia iliaca block may be effective in more than 90% of children, compared with 20% effectiveness of the 3-in-l technique
The fascia iliaca block provides analgesia of the
femoral, lateral femoral cutaneous,
and obturator nerves a
What is a fascia iliaca block?
Fascia iliaca block is a low-tech alternative to femoral or a lumbar plexus
block. The mechanism behind this block is that the femoral and lateral
femoral cutaneous nerves lie under the iliacus fascia. Therefore, a sufficient
volume of local anesthetic deposited beneath the fascia iliaca has the
potential to spread underneath the fascia and reach these nerve
What is a fascia iliaca block?
Fascia iliaca block is a low-tech alternative to femoral or a lumbar plexus
block. The mechanism behind this block is that the femoral and lateral
femoral cutaneous nerves lie under the iliacus fascia. Therefore, a sufficient
volume of local anesthetic deposited beneath the fascia iliaca has the
potential to spread underneath the fascia and reach these nerves
What are the 3 muscular borders of the
popliteal fossa?
The popliteal fossa is essentially a triangle, defined laterally by the tendon
of the biceps femoris, medially by the common tendon of the semitendinosus
and semimembranosus muscles and inferiorly by the two heads of
the gastrocnemius muscle. The two heads of the gastrocnemius muscle
correspond to the popliteal crease.
The mechanism behind The Fascia iliaca block is that the
femoral and lateral femoral cutaneous nerves lie under the iliacus fascia.
Describe a subgluteal sciatic nerve block
lithotomy approach
The patient is placed supine, and the extremity to be blocked is flexed at the hip (90-120 degrees). In this position, the gluteus maximus muscle is flattened and the sciatic nerve lies relatively more superficial, making it palpable in the hollow between the semitendinosus and
biceps femurs muscles. A line is drawn between the ischial tuberosity and
the greater trochanter, and a wheal is raised at its midpoint. A 10- to 15-cm
insulated needle is inserted perpendicular to the skin and advanced until a
motor response involving the foot or ankle is elicited. Twenty to 25 ml of
a local anesthetic solution is then injected.
A supine approach to the sciatic nerve is afforded by the
subgluteal sciatic nerve block (lithotomy approach).
Describe the popliteal fossa approach to the sciatic nerve block (posterior approach)
The patient is positioned prone (or lateral, or supine with the lower extremity flexed at the hip and knee) and the borders of the popliteal fossa are identified by flexing the knee joint. A triangle is constructed-the base is • the skin crease and the two sides are the semimembra-nosus (medially) and the biceps femoris (laterally). A line is drawn from the middle of the base to the apex, bisecting the triangle. The site of insertion of the needle is 1 cm lateral to the line and 7- to l 0-cm above the base of the triangle. A 10-
cm insulated needle connected to a nerve stimulator is introduced through
a skin wheal oflocal anesthesia at a 45- to 60-degree anterosuperior angle.
The sciatic nerve usually is located at a depth of l to 2 cm in an adult. After
careful aspiration, 30 to 40 mL of a local anesthetic is injected.
You have just performed intercostal
nerve blocks at 5 levels to provide
analgesia for fractured ribs. The patient
becomes hypotensive, bradycardic, and
has a seizure. Describe seven (7) actions
to manage the situation.
The following checklist for managing LAST is provided by the American Society of Regional Anesthesia and Pain Medicine.
(I) Get help.
(2) Airway management: ventilate with 100% oxygen.
(3) Seizure suppression, benzodiazepines are preferred.
( 4) BLS/ ACLS with medication adjustments.
5} Infuse 20% lipid emulsion. (6) Alert the nearest facility having cardiopulmonary bypass capability. Failure to respond to lipid emulsion and vasopressor therapy
necessitates institution of cardiopulmonary bypass.
(7) Post LAST events
Local anesthetic systemic toxicity (LAST) symptoms
The patient with hypotension, bradycardia, and seizures following intercostal nerve block
Describe the recommended lipid
emulsion dosing for treatment oflocal
anesthetic systemic toxicity (LAST).
The recommended lipid emulsion dosing for treatment of LAST is:
(I)intravenous bolus of 1.5 mL/kg (LBW) of20% lipid emulsion, such as
lntralipid 20%, over 1 minute.
(2) Continuous infusion at 0.25 mL/kg/min
for at least 10 minutes after cardiac function returns.
(3) If cardiovascular instability continues, repeat bolus once or twice and consider increasingthe infusion to 0.5 mL/kg/min.
(4) Recommended upper limit is 10 mL/
kg lipid emulsion over the first 30 minutes
What medication adjustments” for man·
aging local anesthetic toxicity (LAST).
What are the specific adjustments? What
drugs should be avoided?
Avoid VBCL --> Vasopressin. Beta-adrenergicantagonists (beta-blockers). Calcium channel blockers Avoid local anesthetics (!).
With LAST do this with epi? R
Reduce individual epinephrine doses to less than 1 mcg/kg (epinephrine appears to reduce efficacy oflntralipid emulsion).
Preferred for Ventricular dysrhythmias associated with LAST
Amiodarone
During LAST, do not use this drugs for seizures if there are signs of cardiovascular instability?
Propofol (for seizures) should
not be used when there are signs or expectation of cardiovascular instability
Six mechanistic actions may contribute to lipid resuscitation during the
management of local anesthetic systemic
toxicity (LAST). List the six mechanisms
of action of lipid emulsion rescue.
Six mechanistic actions may contribute to lipid resuscitation: (1) capture
of local anesthetic in the blood {lipid sink effect); (2) increased fatty acid
uptake by mitochondria (metabolic
effect); (3) interference with local anesthetic binding of sodium channels
(membrane effect); (4) activation of Akt cascade (a serine/threonine
protein kinase important in cell survival, proliferation, and migration, also
called protein kinase B; note: this is signal transduction) leading to inhibition
of GSK-3 which is glycogen synthase kinase (cytoprotective effect);
(; and (6) accelerated shunting (pharmacokinetic
effects).
Six mechanistic actions may contribute to lipid resuscitation during the
management of local anesthetic systemic
toxicity (LAST). List the six mechanisms
of action of lipid emulsion rescue.
Six mechanistic actions may contribute to lipid resuscitation: (1) capture
of local anesthetic in the blood {lipid sink effect);
(; and (6) accelerated shunting (pharmacokinetic
effects).
How does lipid interfere with LA
interference with local anesthetic binding of sodium channels (membrane effect);
Lipid treatment and metabolic effect
increased fatty acid uptake by mitochondria (metabolic effect)(
Lipid emulsion lead to the activation of
Akt cascade (a serine/threonine protein kinase important in cell survival, proliferation, and migration, also called protein kinase B; note: this is signal transduction) leading to inhibition of GSK-3 which is glycogen synthase kinase (cytoprotective effect);
What is the incidence of post-dural
puncture headache with spinal anesthesia?
The incidence of post-dural puncture headache with spinal anesthesia is up
to 25%.
Pain after total joint replacement, particularly total knee arthroplasty {TKA}. is
severe. Describe three newer techniques
for postoperative pain management
following total joint replacement
Single-dose and continuous peripheral nerve techniques that block the
lumbar plexus (fascia iliaca, femoral, psoas compartment blocks}, with
or without sciatic nerve blockade, can be used with success for patients
having total joint replacement. Unilateral peripheral nerve block provides
a quality of analgesia and surgical outcomes similar to that of continuous
epidural analgesia, but with fewer side effects. High-volume local wound
infiltration/infusion techniques with a combined administration of local
anesthetics, NSAIDs, and epinephrine [local infiltration analgesia (LIA}]
provide positive results for TKA, more so than THA {total hip).
Inadequate intravascular volume during
the perioperative period can cause a
range of adverse physiologic effects:
describe these effects.
The major complications of hypovolemia, aside from hemodynamic instability,
include decreased oxygenation of surgical wounds (which predisposes
to wound infection), decreased collagen formation, impaired wound
healing, and increased wound breakdown.
At the most extreme levels of
hypovolemia, ATP production to support normal cell functions in those
tissues with the worst perfusion may
be inadequate, leading to cell death
and organ dysfunction.
What are the adverse effects of perioperative hypervolemia?
The major complications associated with hypervolemia include
Pulmonary edema
Congestive heart failure
Edema of gut with prolonged ileus,
and possibly an increase in cardiac arrhythmias.
. Further potential
effects of excessive intravascular fluid include reduced tissue oxygenation
with impaired healing, pulmonary congestion predisposing to pulmonary
infection, and increased myocardial work resulting from ventricular filling
beyond the optimum portion of the Starling curve.
What are the adverse effects of perioperative hypervolemia?
The major complications associated with hypervolemia include
Pulmonary edema
Congestive heart failure
Edema of gut with prolonged ileus,
and possibly an increase in cardiac arrhythmias.
.
Further potential effects of excessive intravascular fluid include
1.reduced tissue oxygenation
with impaired healing
2.pulmonary congestion predisposing to pulmonary infection
3.increased myocardial work resulting from ventricular filling beyond the optimum portion of the Starling curve.
When is the “best” time to institute
patient-controlled analgesia (PCA) in
the perioperative period?
Patient-controlled analgesia (PCA) should be initiated in the PACU after
the patient’s initial pain level is under control. Barash quantifies “initial pain
level is under control” by adding: “when the visual analog pain scores decrease
to ~3 (0-10 scale), the patient may be started on PCA:’
What four ( 4) criteria must a patient
meet in order to receive patient-controlled
analgesia (PCA)?
Because patient-controlled analgesia (PCA) requires the patient to control
the delivery system, candidates for PCA must: (I) be cooperative; (2) be
able to understand the concept; ( 3) follow the directions of use; and, ( 4) be •
able to push the demand button
List five (5) variables current PCA models have for allowing selective dosing of agents.
Current PCA models have at least five different variables for selective dosing: (1) an initial loading dose; (2) a demand dose or bolus dose; (3) lockout interval; (4) a basal continuous infusion rate; and, (5) 1-hour and 4-hour maximum dose limits
