Anesthesia Flashcards
What is the ideal thyromental distance in airway evaluation?
Greater than 6 cm
What are the preoperative NPO guidelines
ASA Classifications system
Common sources of error for pulse oximetry
(10 pts)
-Shivering
-Fingernail Polish
-Corboxyhemoglobin
-Methemoglobin
-Methylene Blue
-Hypothermia
-Hypotension
-Hypovolemia
-Hypoxia
-Ambient light
What are the most sensitive EKg monitors to ischemia
Leads II and V5
EKG helps determines
Ischemia, disarrhythmias, and pacemaker function
When is invasive BP indicated
-In major surgeries
-Hemodynamic instability
-Vasocactive meds
-Frequent blood draws.
Too large of a BP cuff?
falsely low BP
Too small of a BP cuff?
Falsely elevated bP
CO2 monitoring allows for measurement of:
-Assessment of ventilation
-Assessment of ciculation
-Identification of intubation
-Identification of anesthetic circuit malfunction (leaks, disconnection)
Bispectral index
Yes EEG data via scalp electrodes to record the depth of anesthesia via IV or inhalation
Levels of consciousness
Responsivness for minimal, moderate, deep, general
Airway, spontaneous ventilation, cardiovascular function
for minimal moderate, deep, general
T/F: LMA’s can be used for airway emergencies when intubation has failed.
True, it is a suprglottic airway and does not protect the airway though.
what does oral RAE stand for?
Ring-Adair-Elwyn
When is a cricothyrotomy used?
It is used during airway emergencies when other nonsurgical attempts at securing the airway have failed.
Volume of distribution
Dose of drug administered/concentration of drug in plasma
-Decreased by high protein binding affinity, ionization, decreased lipid solubility.
What is drug clearance?
The volume of plasma cleared of drug in mL per minute as a result of renal elimination and metabolism (liver and other tissues: kidney, lung, gastrointestinal tract)
How is renal elimination improved
It is improved with increased water solubility and inhibited by protein binding and lipid solubility
Elimination half time:
Time required to decrease drug concentration by 50% _5 half times required for total elimination.
Redistribution
Drugs preferentially distribute to highly perfused tissues (eg brain, heart, kidneys)
Eventually a gradient is reached that allows perfusion to the less perfused tissues (fat, skeletal muscle)
First-pass hepatic effect
Oral drugs are absorbed by the GI tract and pass through the liver via the portal circulation before entering the systemic circulation
Drugs are metabolized in this process
PAP
Pulmonary artery pressure-the partial pressure of volatile agent in the brain is in equilibrium with the blood and alveoli
MAC
Minimum alveolar concentration is the concentration (partial pressure) of volatile anesthetic (at 1 atm and measured during steady state) that prevents movement in 50% of patients during surgical stimulus.
The higher the MAC, the less the potency
MAC of Sevo
2.1
What are the advantages and disadvantages of Sevo?
Advantages-Rapid induction/recovery
Minimal airway irritation
Disadvantages-Potential renal concerns ( compound A)
What are the advantages and disadvantages of Iso?
Advantages-Relatively slower onset of action, Pungent odor
Disadvantages-Coronary steal effect
MAC of Iso
1.15
What are the advantages and disadvantages of Des?
Advantages-Rapid induction/recovery
Disadvantages-Airway irritation
MAC of des
6.0
What are the advantages (4) and disadvantages (6) of Nitrous Oxide?
Advantages-
-Analgesia,
-second gas effect,
-safe in malignant hypothermia susceptible patients,
-rapid induction/recovery
Disadvantages-Expansion of air-filled spaces, higher combustion risk, PONV, megaloblastic anemia, Chronic use may result in peripheral neuropathy, possible teratogen
MAC of Nitrous Oxide
105
True/FalseBlood pressure reduces from halothane, isoflurane, desflurane, sevoflurane
True, only NO seems to cause it to rise
When does HR increase on iso, des, sevo
Only if MAC is greater than 1.5
Cardiac contractility
All volatile agents cause a decrease in contractility
Volatile anesthetics impact on respiratory rate, TV, MV, and CO2 level
Most volatile anesthetics (except isoflurane)
1-Increased respiratory rate
2-Decreased tidal volume
3-Decreased minute ventilation
4-Produce a high carbon dioxide level
Which opioids are included in the Morphine group?
(10 meds)
Morphine
-Codeine
-Hydrocodone
-Oxycodone
-Oxymorphone
-Hydromorphone
-Nalbuphine
-Butorphanol
-Levophanol
-Pentazocine
Which opioids are included in the phenylpiperidine group?
-Meperidine
-Fentanyl
-Sufentanil
-Remfentanil
What is the mechanism of action of opioids?
-Agonist at various endogenous opioid receptors (Mu1, Mu2, delta, kappa, sigma) within the nociceptive pathways.
-Involves decreased presynaptic release of acetylcholine and substance P
What are the effects of opioids on the:
CNS
CV
Respiratory
GI
GU
What concerns do you have with opioids?
-Tolerance and dependence
-Chest Wall rigidity
-Crosses placenta
-Histamine release with morphine and meperidine
How do you reverse opioids?
Naloxone
-Adult dose is 0.04 to 0.4 mg IV; repeat dose or increase dose to 2 mg if no response.
-Pediatric dose: 0.001 to 0.005 mg/kg IV
Pseudoallergy of opioids
Minor symptoms of flushing, hives, diaphoresis, dysphagia, facial/airway swelling,
IV Meds-Bartbituates include
Pentobarbital, methohexital
What is the mechanism of action of barbiturates?
GABA potentiation, direction action on GABA, receptor chloride channels, some action on calcium ion channels
What is the induction/sedation dosage of barbituates
Induction: 1 to 1.5 mg/kg
Sedation: 0.75 to 1 mg/kg followed by 0.5 mg/kg every 2-5 minutes
Ketamine-MOA
(5 receptors)
Various receptors (NMDA agonist, opioid, monoaminergic, muscarinic, calcium ion channels)
What are the pharmacokinetics of Ketamine?
-High lipid solubility: Crosses blood-brain barrier easily
-Hepatic metabolism
What is the dosage of Ketamine
Induction: 1 to 4.5 mg/kg IV
Sedation (IV): 1 to 2 mg/kg IV followed by 0.25 to 0.5 mg/kg IV very 5 to 10 min
Sedation IM: 2 to 5 mg/kg IM
Indications for Ketamine
(3 pts)
-Dissociative anesthetic with analgesic properties
-Induction agent
-Sedation
Effects of Ketamine
CNS
CV
Respiratory
T/F: Ketamine contraindicated in head trauma
True, because it increased CBF and ICP
What can help mitigate the hallucinatory issues of Ketamine?
Benzodiazpines
T/F: Ketamine depresses respiratory rate significantly
False
T/F: Ketamine decreases secretions
False, it increases and so sometimes people pretreat with hypersalivation
Is Ketamine a bronchodilator or bronchoconstrictor
It is a bronchodilator
Benzodiapeines
Midazolam-Versed
Diazepam-Vallium
Lorazepam-Ativan
Alprazolam-Xanax
MOA of benzos
mediated by GABA
Are benzodiazepines anticonvulsants?
Yes, they are
Effects of Benzodiazepines
CNS
CV
Respiratory
Which drug decreases metabolism of Benzodiazpines
Erythromycin
What is the reversal agent for Benzos?
Flumazenil: Competitive Antagonist
Adult dose: 0.2 mg IV; repeated doses may be given at 1 minute intervals to a maximum of 3 mg
Pediatric Dose: 0.01 mg/kg may be repeated at 1 - minute intervals to a maximum dose of 1 mg
What is the danger of flumazenil?
the half life is less then benzodiazepines so the resection is possible of recurring.
Benzodiapines doses…What is the duration for Midazolam (Versed), Diazepam (Vallium), and Lorazepam (Ativan)
What is dexmedetomidine used for?
Sedation in short term in intubated patients?
MOA of dexmedetomidine?
alpha 2 adrenoceptor agonist
What are the effects of alpha, beta receptors.
Effects of dexmedetomidine
CNS
CV
Respiratory
What are the nueromuscular blockers used for?
Skeletal muscle relaxation during intubation, ventilation or during treatment of laryngospams refractory to positive pressure.
What are the depolarizing agents?
Succinylcholine
What are the non depolarizing agents
Rocuronium, Vecuronium, Cisatracurium
What is the reversal agent for neuromuscular blockers?
It is Neostigmine (Anticholinesterase, but this is only for nondepolarzing agents only)
What is neostigmine’s MOA
It inhibits acetyl cholinesterase, leading to a build up of acetylcholine within the neuromuscular junction (NMJ)
Dosage for Neostigmine
0.03 to 0.07 mg/kg over 1 minute
What are the side effects of neostigmine?
Bradycardia (that is why atropine or glycopyrollate are also given)
What drugs are given in with neostigmine to fight the effects of bradycardia?
Glycopyrollate and atropine?
MOA of Succinylcholine
Competitive agonist at ACh receptor
-Produces a sustained depolarization of the post junctional mebrane of the NMJ
MOA of Succinylcholine
Competitive agonist at ACh receptor
-Produces a sustained depolarization of the post junctional mebrane of the NMJ
What are the pharmocokinetics of succinylcholine?
Hydrolyzed by plasma cholinesterase
Onset of Succinylcholine?
30 to 60 seconds
What is the adult dosage of succinylcholine for induction?
0.6 mg/kg IV
What is the dosage of Succinylcholine for treating a larygospasm?
0.1 to 0.5 mg/kg IV or 4 to 6 mg/kg IM
Side effects of Succinylcholine
-Fasiculations (body aches)
-Hyperkalemia
-Cardiac dysrhythmias
-Malignant hyperthermia
Contraindications of Succinylcholine
Name 5 non-depolarizing agents?
vecuronium, rocuronium, pancuronium, cisatraciruium, atracurium
What is the MOA non-depolarizing agents
Competitive altoists of EACh at post junctional membrane
Which non-depolarizing agents can be used in renal or hepatic failure patients?
Cisatracurium because it is degraded via Hoffman elimination
Hofmann elimination and ester hydrolysis occur from both central and peripheral compartments
an elimination reaction of an amine to form alkenes
Dosage of non depolarizing agents
Local anesthetics-Amides
How are they metabolized?
Metabolized by the liver microsomal enzymes, incidence of allergic reaction is lower than with esters and is likely related to the preservative
Local anesthetics-Esters
How are they metabolized?
Esters: Metabolized by plasma psudocholinesterase (consider if severe liver disease); p aminobenzoic acid is a metabolite and may be associated with allergy in some patients.
Patient’s with self allergies may have a higher incidence of allergy to…..
esters
MOA of local anesthetics
Inhibits depolarization and impulse propagation of nerve cells through blockade of sodium ion channels in the inactivated state.
Amide anesthetics
lidocaine, bupivacaine (marcaine), ropivacaine, mepivacaine (carboacinae), articaine
Anesthetic duration of action, maximum dosage
for Lidocaine, Mepivcaine, Prilocaine, articaine, and Bupivacaine
High doses of anesthetics
CNS
CV
Respiratory
SIMV stands for
Synchronizd intermittent mandatory ventilation
What is SIMV?
Patients can take additional spontaneous breaths that are not supported by the ventilator
Indications: Facilitating from full ventilatory support to partial support
What ar the advantages of SIMV?
-Maintains respiratory muscle strength by avoiding muscle atrophy
-Decreases mean airway pressure
-Facilitates ventilatory discontinuation, weaning
What is a complication of SIMV (stacking?
Mechanical rate and spontaneous rate may be asynchronous and cause stacking (incomplete expiration resulting in residual air adding to volume of next inspiration.”
-This may cause barotrauma
CPAP
Continuous postive airway pressure
-Positiv pressure provided continuously throughout inspiration and expiration.
BiPAP
Bilevel positive airway pressure
-Inspiratory and expiratory positive airway pressure in preset
-The difference between the two pressures determines the total volume
PEEP
Positive end expiratory pressure
-Positive pressure only applied during the expiratory phase
-Helps prevent early airway closure and alveolar collapse at the end of expiratory by increasing and normalizing the functional residual capacity (FRC) of the lungs
For extubation, what should be your RSBI, NIF, and FiO2 score?
NIF should be -30
FiO2 should be <60%
RSBI should be l<105
Causes of HTN-Perioperative
HTN, hypoxia, drug errors, pain,
Uncommon causes of HTN
MH, pheochromocytoma, Hyperthyroidism, fluid overload
What options should you consider pharmacologically for HTN
Esmolol (short acting)
Labetalol
-Calcium channel blockers
-Hydralazine
-Nitroprusside
-Nitroglycerine
How to treat HTN with bradycardia
Hydralzine 2.5 to 5.0 mg IV every 10 minutes to a max dose of 24 mg
Nitroglycerine sublingual tablet 0.4 mg every 5 minutes
How to Treat HTN with tachycardia?
Esmolol (5 to 10 mg) every 3 minutes up to a max dose of 100 to 300 mg or labetalol (5 to 10 mg) every 10 minutes to a max dose of 300 mg
Hypotension-etiology perioperative?
Hypovolemia
-administered medications/depth of anesthesia,
-cardiogenic (dysrhythmia)
-myocardial infarction
-pulmonary ( PE, Pneumothorax)
-Anaphylaxis
Which patient’s are more likely to experience hypotension?
Those taking a diuretic and angiotensin-converting enzyme (ACE inhibitor ) or angiotensin receptor blockers (ARB) inhibitor are more prone to experience hypotension.
First line of action for hypotension
-Intravenous fluid bolus should be the first line of treatment ->250 mL of LR or normal saline solution
Treating hypotension with bradycardia?
Atropine 0.5 mg every 3 to 5 minutes up to a maximum dose of 3.0 mg
Hypotension with tachycardia
Phenylephrine 1% (alpha agonist with reflex bradycardia effect) 100 ug per dose every 5 minutes
Hypotension with normal heart rate
Ephedrine (alpha and beta agonist 5 mg every 5 to 10 minutes
Hypotension related with anaphylactic reaction
Epinephrine IM 0.3 mg of 1:1000 (mild case), epinephrine IV 10 to 20 ug 1:10,000 (severe case
Tachycardia
1-Determine if sinus tachycardia, obtain ECG
2-Common causes of sinus tachycardia preoperatively include pain, anxiety; other causes include fluid depletion, hypoxia, pulmonary embolism, residual effects of anesthetics/medications, hyperparathyroidism, acute coronary syndrome, chronic obstructive pulmonary disease
3-If tacharrythmia (vagal maneuvers, adenosine if paroxysmal supraventriclar tachycardia), refer to ACLS guidlines
How to manage perioprative bradycardia?
Angina-how to manage
Syncope-How to manage?
How to manage a laryngospasm
How to manage a bronchospasm
What is malignant hyperthermia
Hypercatabolilc state that develops in genetically susceptible individuals as a response to a variety of inhalation anesthetics such as sevofluroane, desflurane, isoflurane, as well as succinylcholine
What is the pathogenesis of MH?
Mediated by calcium release form the sarcoplasmic reticulum in skeletal muscle
What are the early signs of MH
Hypercapnia, tachycardia, muscle ridgidity
What are the later signs of MH
ECG changes 2ndary to hyperkalemia, rhabdomyolysis (elevated plasma creatine kinase and urine myoglobin–dark urine), and hyperthermia.
What is the most common cause of death in MH
Hyperkalemia and.coagulopathy from hyperthermia
What is the treatment of MH?
What is the 4 2 1 rule
Why is albumin a colloid?
It contains large molecular weigh substances with less membrane permeability to allow for increased intravascular osmotic pressure (albumin, hetastarch)
Why is albumin a colloid?
It contains large molecular weigh substances with less membrane permeability to allow for increased intravascular osmotic pressure (albumin, hetastarch)
How to calculate NPO deficit
Number of hrs NPO x maintenance requriement
What does each unit of RBC’s increase hematocrit and hemoblogin by?
Hematocrit by 3% and Hemoglobin by 1%
What is the ratio of crystalloid used to restore blood loss?
3 cc of crystalloid are used for every 1 cc of blood lost.
If using RBCs or colloid to restore volume,what restoration ratio can be used?
1:1
What are the risks of transfusion
1-Hemolytic/nonhemolytic immune reactions
2-Infection (viral/bacterial/parasitic)
3-Coagulopathy disorders (eg, disseminated intravascular coagulation)
Administer product using normal saline (avoid using LR solution)
Platelets increase the count of platelets by?
1 unit will increase 5,000-10,000
In general, what platelet count minimum is needed for surgery?
50,000/mm3
What does FFP have?
It contains all the coagulation factors; may be used for several of warfarin as well as replacement of deficient factors?
What is cryoprecipitate?
Enriched with fibrinogen as well as von Willebrand factor, Factor VIII-C and factor XII
What is the name of the Post-Op anesthesia recovery discharge criteria?
Modified Aldrete
What 5 things are taken into consideration for the Modified Aldrete discharge score?
1-Respiration
2-Oxygen Saturdation
3-Consciousness
4-Circulation
5-Activity
What score must there Aldrete score be above for discharge?
> 8
What are your serotonin antagonists for PONV?
Odansetron
Dolasetron
What works against Histamine for PONV?
Promethazine
What targets the dopamine receptors for PONV
Droperidol
Metoclopramide
What PONV med works gains ts the muscarine receptor?
scopalamine
What are the causes of delayed awakening?
1-Overdose
2-Hypothermia
3-Hypercarbia
4-Hypoxia
5-CVA
What can you do to troubleshoot delayed awakening?
1-Rule out stroke
2-Vitals signs assessment
3-electrolyte and glucose level eval
What meds can you give someone with delayed awakening?
1-Flumazenil
2-Naloxone for opiates
3-Physostigmine for reversal of anticholinergics?
Emergency doses for Naloxone, Atropine, Vasopressin, Epinephrine and Lidocaine given down the endotracheal tube
What are the main anatomical differences between pediatric and adult airways?
1-Tongue is larger
2-Epiglottis is floppy and omega shaped
3-Larynx if funnel shaped
4-Narrowest point of the airway is in the subglottic region.
How do you determine the size of an endotracheal tube for a pediatric patient?
Age /4 + 4
True or False, pediatric airways are more reliant on the diaphragm?
true
True/False: Cardiac output in pediatrics is mostly driven by HR
True
T/F: Elderly patients have decreased MAC
True, decreased minimal alveolar concentrations (increased sensitivity to inhalation agents)
T/F: Elderly patients are more likely to be HTN
True, because of decreased vessel compliance, decreased cardiac output and HR
T/F: Elderly patients have an increased V/Q mismatch
True
BMI
stands for body mass index in kg/m2
What are BMI ranges?
Overweight > 25 BMI
Obese - BMI >30
Severe/morbid obesity BMI>40
What is the single biggest predictor of a probelmeatic intubation in obese patients?
Neck circumference 40-60 cm neck circumferences mean probelematic intubations
What is Pickwickian syndrome?
Obesity hypoventilation syndrome
Obesity & Physiological differences with respiratory function?
1-Decreased chest wall compliance
2-Decreased function residual capacity; adequate pre-oxygenation is necessary prior to intubation
Obese patients have a high GFR? T/F
True, with quicker renal clearance except for lipophilic drugs
Preoperative risks for diabetic patients?
8 come to mind
1-Dehydration (osmotic diuresis with hyperglycemia)
2-Autonomic dysfunction (postural hypotension)
3-Gastroparesis/increased aspiration risk
4-Wound healing
5-Infection
6-Stiff joints
7-Diabetic ketoacidosis risk (type 1 DM)
8-Hypoglycemia
Management of diabetic patients
1-Schedule type 1 DM in early morning
2-Obtain glucose level on arrival
3-Consider halfing the daily dose
What can occur with hyperglycemic patient’s and what symptoms can they present with?
DKA for type 1 DM, or hyperglycemic hypoerosmolar nonketotic state (type II DM)
1-Tachypnea, tachycardia, abdominal pain, temp alteration
2-Ketone breath in type 1 DM
In office, how do you manage DKA
1-Regular insulin infusion 0.1 units/kg/h
2-Normal saline 5 to 10 mg/kg/h, you can add 5% glucose if blood glucose is less than 250
3-REplenish potassium 03. to 0.5 mEg/Kg/h
What is diaphoresis
Diaphoresis refers to excessive sweating, commonly associated with an underlying medical condition that alters hormone levels in the body.
What are the symptoms of hypoglycemia?
1-Mental status change
2-Diaphoresis
3-Tachycardia
4-Possible seizure disorder
How to manage hypoglycemic patients?
1-oral glucose
2-1 to 2 mg of IM glucagon
3-10 - 25 grams of glucose with IV access
What symptoms may occurs with hyperthyroidism?
1-Hyperpyrexia (extreme body temp)
2-Tachycardia
3-HF
4-CNS changes
5-GI disturbances
What can cause hyperthyroidism?
1-Infection
2-Trauma
3-Surgical sTress
4-Withdrawl/medicine compliance
In neurological trauma patients, what fluids?
Isotonic fluids only to prevent intracranial fluid shifts
Which med do you avoid in Neurologic trauma patients?
Ketamine!
Which meds should you be careful of with Myasthenia gravis patients?
Ester anesthetics especially if patient is receiving anti cholinesterase therapy.
What med do Myasthenia Gravis patient’s have decreased metabolism for?
Succinylcholine
What therapy are Myasthenia Gravis patients on?
antichoinesterase therapy
What is the treatment of myasthenia gravis?
Anticholinesterases
Thymectomy
Immunosuppression
Plasma exchange
IV immune noglobulin
What symptoms can present with a myasthenia crisis
1-Muscle weakness
2-Bronchospams
3-Wheezing
4-Respiratory failure
5-Diaphoresis
6-Cyanosis
What is the preferred method of airway treatment for asthematics
Laryngeal airway over ET tube
Which. meds inhibit bronchoconstriciton for asthmatics
1-Propofol
2-Ketamine
Which paralytics should be avoided for asthmatics
Atracurium and mivacurium because they induce histamine release
Whare are the main treaters of bronchoconstriction
Beta 2 agonists
Spastic CP vs Dyskinetic CP
1-Spastic CP-injury to the cerebral motor cortex
2-Dyskinetic-Inure to the basal gangliay
Cerebral Palsy
A nonprogressive movement disorder that results form injury to the developing brain
Ataxic CP
injury to the cerebellum
Characterized by tremor, loss of balance, and difficulty with speach
Preop eval of cerebral palsy patients
1-Degree of spacicity and limb contracture
2-Evaluate hx of seizure episodes
3-Evaluate severity of GI reflux and impaired pharyngeal function with pooling of oral secretions
4-Evaluate respiratory function, airway tone, restrictive pulmonary disease
Cerebral Palsy patients and nondepolarizing skeletal muscle realxants
CP patients may need higher dosage due to drug resistance
