Pre Op Exam
Inhaled Anesthetics
Local Anesthetics
IV Anesthetics
Blame Anesthesia
100
What are the classes of the Anesthesiologists' Physical Status Classification System?
ASA 1: Normal healthy patient
ASA 2: Patient with mild systemic disease that results in no functional limitations
ASA 3: Patient with systemic disease that results in functional limitations
ASA 4: Patient with severe systemic disease that is a constant threat to life
ASA 5: A moribund patient who is not expected to survive more than 24h with or without the operation
100
What is MAC?
Minimal alveolar concentration. Concentration of drug needed to prevent movement in response to surgical incision in 50% on patients. Allows for comparison of the potencies of the different agents - the higher the MAC, the lower the potency.
Isoflurane - 1.15
Sevoflurane - 2
Desflurane - 6
Nitrous Oxide - 105
MAC is impacted by a variety of factors such as concomitant drug use, age, electrolyte abnormalities, temp and pregnancy. For example, fever and chornic EtOH use increase MAC meaning that more anesthetic is needed. Conversely, hypothermia and acute EtOH intox lower MAC.
MAC values are additive ie 1/2MAC of nitrous can be added to 1/2MAC of the volatile anesthestics
100
How much lidocaine is okay to use in a patient?
3-5mg/kg
100
Known as “Thriller Killer”, describe its MOA and any things to beware of ?
Propofol; GABA A agonist (influx of Cl- ions); Must use w/in 6 hours (bacterial growth), Possible cross rxn with egg allergy
100
What is the mortality rate from anesthesia?
1/250,000
200
What is the Mallampati classification? Describe the classes
1- soft palate, uvula, tonsillar pillars
2- soft palate and uvula
3- soft palate and base of uvula
4- soft palate not visible
200
True or false - the LESS soluble a volatile agent, the LONGER it takes to get a clinical effect
False. The more soluble an agent, the longer it takes to get a clinical effect. In other words, solubility is inversely related to speed of onset. Factors that speed uptake include a high inspired concentration of the agent, high alveolar ventilation and low solubility of the agent.
200
How much bupivicaine is okay to use in a patient?
2.5 mg/kg
200
This IV anesthetic isn’t used as frequently as it was 20+ years ago, often used in cardiac settings. Beware of this well known side effect.
Etomidate; less hypotension and tachycardia vs propofol; Adrenal suppression post op
200
You come to post op check your patient and they complain of hand numbness in the ulnar distribution, what did your anesthesiologist do wrong during the surgery? What should they have done?
Arms < 90 degrees, hands supinated or in neutral position, Padding under elbows/wrists
300
A patient tells you they have a family history of malignant hyperthermia. What anesthetic agents will you want to avoid?
All inhaled anesthetics and succinylcholine.
300
What is the least potent inhaled anesthetic? What are relative contraindications or problems with the use of this agent? (Name 3)
Nitrous oxide.
Used in addition to volatile anesthetics to decrease side effects associated with higher MAC (ie hypotension, tachycardia, myocardial depression, QT prolongation)
Problem with nitrous is ability to enlarge air filled cavities, increasing the volume or pressure of the cavity. Occurs because nitrous is able to diffuse into the cavity faster than air can exit. Cavities of clinical importance are GI tract, middle ear and brain after craniotomy. Nitrous can also expand the volume of a pnuemothroax, venous air embolism or air bubble placed in the eye during retinal surgery.
Another issue is diffusion hypoxia. Can occur when a large amount of nutrous exits the body, filling the alvenoli and resulting in hypoxia. To prevent this, a high concentration of oxygen should be administered at the end of an anesthetuc as the patient is emerging.
Finally, its a possible teratogen and should be avoided in first trimester.
300
Symptoms of lidocaine toxicity?
Perioral tingling, metallic taste, dizziness, confusion, seizure, bradycardia, AV block, hypotension
300
This IV anesthetic can actually increase a patient’s BP, HR as well as their ability to see dead people (they’re everywhere). Describe its MOA, and what cool effect does it have on pain control?
Ketamine; NMDA Antagonist; Decreases opioid tolerance and sensitization of central pain pathways
300
You notice your patient is bleeding more than expected, but you demand the OR temperature be a cool 65 degrees because you’re sweating a lot and the OR is your domain. What could your anesthesiologist have done to prevent this annoying bleeding whilst you remain cool while gowned up?
Bair Hugger, forced air warming is the most cost effective and efficacious method of preventing perioperative hypothermia ,which can lead to coagulopathy and other complications
400
What 5 components make up an airway exam?
1. Mouth opening - assessed with finger breadths. Normal is 3 or more
2. Checking for loose teeth
3. Thyromental distance - distance between thyroid cartilage and the mandible. Normal is 3 finger breadths or more
4. Neck ROM
5. Mandibular protrusion- bite upper lip with lower teeth; predictor of ability to sublux the mandible during intubation
400
Describe the general physiologic effects that volatile anesthetics have on the neuro / CV / respiratory / MSK systems.
Neuro - decrease cerebral metabolism, increase cerebral blood flow and intracranial pressure
CV - decrease MAP by decreasing SVR
Pulm - cause bronchodilation, decrease airway reflexes. Decrease tidal volume and increase RR in a patient breathing spontaneously. Iso and des are pungent and can cause laryngospasm and airway irritation
MSK - relax skeletal and smooth muscle by inhibiting nicotinic acetylcholine receptors
400
Name 3 things that can be added to local anesthetics to lengthen their duration of action.
Epinepherine
Clonidine
Sodium bicarb
400
An ICU patient on the ventilator is showing signs of metabolic acidosis, kidney failure and heart failure, name this constellation of symptoms. What is another symptom that is characteristic?
“Propofol infusion syndrome”; Rhabdomyolysis; infusions at high dose (>4mg/kg/hr) and >48 hrs typically; HIGHLY FATAL up to 50% mortality
400
Your slave (the med student) is trying to retract with all their strength but can’t give you a large enough visual field, you instinctively know the patient isn’t fully paralyzed, to which you ask the gas man “what’s their twitches”? Describe how neuromuscular blockade is monitored, where and what measurement is used?
Peripheral nerve stimulator; Best location = wrist/hand to monitor adductor polis; Monitor depth of blockade – Train or four, 0-1 twitch for intubation, 2-3 for intraabdominal surgery, 4 twitches to extubate
500
Regarding intubation, what is your concern in a patient with a history of RA or down syndrome?
Atlantoaxial instability. Estimated to be present in 13% of people with DS and 20% of patients with RA.
Spinal cord compression can occur with extreme cervical ROM. Sx of this are spasticity, myelopathy, neck pain and radicular symptoms.
Transverse ligament holds the odontoid process of C2 against the posterior aspect of the anterior arch of C1. If this ligament becomes lax, C1 (carrying the occiput) can sublux anteriorly on C2, compressing the spinal cord
http://anesthesiology.pubs.asahq.org/article.aspx?articleid=1942107
500
What receptor is mutated in MH? What is the first sign that MH is occurring? Treatment?
Mutations encoding for abnormal RYR1 or DHP receptors have been found in a majority of MHS patients. MH occurs due to release of calcium from sarcoplasmic reticulum of skeletal muscle cells, causing intense muscle contraction.
First sign is usually increase in EtCO2. Then tachycardia, hypertension, hyperthermia.
Tx is removal of triggering agent, immediate administration of dantrolene (2.5mg/kg) and supportive therapy. Dantrolene inhibits calcium release from SR, halting muscle contraction.
500
Your patient has gotten 15 mg/kg lidocaine and is not doing so hot. Aside from supportive care, what options do you have to revive the patient?
Lipid rescue.
The mechanism of action of lipid emulsion is not well understood and may be multifactorial. Historically, lipid was thought to act as a "lipid sink," where lipid would bind the local anesthetic to remove it from target tissue. A different emerging theory is that lipid emulsion carries or "shuttles" the LA from the heart and brain to the organs that store and detoxify the drug. Lipid emulsion may also have direct cardiotonic effects involving sodium channels, fatty acid processing, and mitochondrial metabolism or permeability, which would enhance the shuttling effect.
500
What specific enzyme does Etomidate inhibit to induce adrenal suppression?
11B-hydroxylase
500
Who is responsible for cases that start late?
VIR