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93 Cards in this Set
- Front
- Back
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Byproduct of inhaled anesthetic metabolism that stimulate formation of antibodies associated with hepatitis |
Triflouroacetate |
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Major beneficial feature of the inhaled anesthetics |
Ability to decrease plasma concentrations as easily and as rapidly as they are increased |
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Potent volatile anesthetics are liquids at ambient temperature and pressure except |
Desflurane |
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Genotoxicity of volatile anesthetics can be inferred by demonstrating _____ in lymphocytes from peripheral blood smear. |
Sister chromatid exchanges (SCE) |
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True or false. Vapor pressure is independent of the temperature and proportional to the volume of the liquid |
False. Vapor pressure is independent of the volume of the liquid and is proportional to the temperature |
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Defined as when the liquids vapor pressure exceeds the atmospheric pressure. |
Boiling point |
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The concentration of any one gas in a mixture of gases in solution depends on 2 factors: |
*partial pressure in the gas phase in equilibrium with the solution *solubility within that solution |
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True or false. Volume of a gas in the gas phase is directly proportional to mass according to the ideal gas law |
True |
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What physiologic tissue group is referred to as the "tissues of desired effect" |
Vessel-rich group (VRG) - brain, heart, kidney, liver, digestive tract and glandular tissues |
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What comprises the tissues of accumulation? |
Muscle and fat group |
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The ratio of dissolved gas (by volume) in two-tissue compartments at equilibrium |
Partition coefficient |
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True or false. The faster the fraction alveolar rises relative to fraction inspired, the faster the speed on induction |
True |
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The most important factor in rapidly increasing the fraction inspired to the desired concentration |
High fresh gas flows (>4L/min) |
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2 ways to speed the equilibration of fraction alveolar with fraction inspired |
*increase minute ventilation *decrease FRC |
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The most important factor in the rate of rise of Fa/Fi |
uptake of anesthetic from the alveoli into the bloodstream |
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True or false. The greater the uptake, the faster the rate of rise of Fa/Fi |
False. greater uptake means slower rate of rise |
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Why does the muscle compartment equilibrates far more slowly than the VRG even though they have the same partition coefficient? |
There is a 25-fold difference in perfusion between VRG and muscle |
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True or false. After long anesthetic exposures (>4hrs), the high saturation of fat tissue may play a role in delaying emergence |
True. |
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The administration of a higher partial pressure of anesthetic than the alveolar concentration (Fa) actually desired for the patient |
Overpressurization |
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True or false. Changes in cardiac output do not affect the rate of rise of Fa/Fi in more soluble volatile agents |
False |
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The primary determinant of the rate of fall of Fa |
Solubility |
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How much anesthetic must be eliminated in the CNS before emergence |
80-90% |
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A phenomenon where washout of high concentrations of N20 can lower alveolar concentrations of oxygen and carbon dioxide |
Diffusion hypoxia |
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It is the most potent of the volatile anesthetics in clinical use, undergoes essentially no deterioriation during storage for up to 5 years |
Isoflurane |
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Unique characteristics of Desflurane compared to other volatile anesthetics |
*near absent metabolism to serum triflouroacetate *most pungent *induces tachycardia and hypertension |
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Exposure of this volatile anesthetic to dried absorbent can form carbon monoxide and can cause high heat and fire via an exothermic reaction |
Sevoflurane |
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Dose dependent nephrotoxin in rats, but has not been associated with renal injury in human volunteers or patients, with or without renal impairment even when FGFs are 1L/min or less. |
Compound A (vinyl halide) |
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An inhaled anesthetic that has a quick onset and offset, minimal effects on the cardiovascular and neural systems, and its is not a trigger for malignant hyperthermia |
Xenon |
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What are the unique characteristics of nitrous oxide |
*insoluble in blood *does not produce significant muscle relaxation *inactivation of vit B12 *absorption and expansion into air filled structures and bubbles |
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Inhaled anesthetic that is contraindicated for tympanoplasty because the increased pressure can dislodge a tympanic graft |
Nitrous Oxide |
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The alveolar concentration of an anesthetic at one atmosphere that prevents movement in response to a surgical stimulus in 50% of pxs. |
Minimum alveolar concentration |
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True or false. The lower the MAC the more potent the anesthetic agent |
True |
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At what MAC will the inhaled anesthetic agents will provide loss of self awareness and recall |
0.4 - 0.5 MAC |
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Factors that increase MAC |
*Hyperthermia *Hypernatremia *Chronic ethanol abuse *Inc central neurotransmitter levels (MAOIs, cocaine, ephedrine, levodopa) |
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True or false. Red haired females have 19% increase in MAC compared with dark haired females. |
True. Mutation in the melanocyte stimulating hormone receptor (MC1R) allele |
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True or false. MAC increases with age |
False |
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What are the effects of volatile anesthetics on the CMR02 and ICP |
Decrease CMR02 and increase in ICP |
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The increase in CBF with increasing anesthetic dose occurs despite decreases in CMR02. This phenomenon has been called |
Uncoupling |
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Sevoflurane preserves autoregulation at what MAC |
1 MAC |
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Mild increases in ICP with isoflurane administration are blocked or blunted by. |
hyperventilation (hypocarbia) or barbiturate coadminstration |
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Defined as impairment to the mental processes of perception, memory, and information processing post operatively |
Postoperative Cognitive Dysfunction |
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What changes in the latency and amplitude during SEP will volatile agents cause? |
Increase in latency and decrease in amplitude |
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True or false. Volatile agents are avoided in cases which require Motor evoked potentials (MEP) |
True. MEPs are sensitive to depression by volatile anesthetics. |
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Effects of Nitrous oxide to the CBF and CMR02 |
Preserved CBF but decreased CMR02 |
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The primary mechanism of volatile anesthetics to decrease BP |
Relaxation of vascular smooth muscle |
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The mechanism by which isoflurane and desflurane causes transient HR surges |
Pungency of these anesthetics which stimulates airway receptors to elicit a reflex tachycardia |
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The sum of the partial pressures of each gas in a mixture of gases equals the total pressure of the entire mixture |
Dalton's Law |
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Why is pediatric induction by spontaneous breathing of inhaled anesthetics are so much quicker than adult inductions? |
Low FRC relative to Alveolar ventilation |
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How does xenon provide some degree of analgesia |
N-methyl-d-aspartate (NMDA) receptor inhibition |
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Effect of volatile anesthetics on myocardial contractility |
Decreased contractility but does not affect the ability of the myocardium to respond to an acute increase in cardiac preload. |
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Increases sympathetic nervous system activity and vascular resistance when given in a 40% concentration |
Nitrous oxide |
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True or false. Isoflurane, sevoflurane and desflurane sensitize the heart to the arrhythmogenic effects of epinephrine. |
False, it does not sensitize |
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How does volatile anesthetics predispose pxs to ventricular dysrhythmias including torsades de pointes? |
Volatile anesthetics prolong QT interval |
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Why does isoflurane creates a potential for coronary steal |
Isoflurane (and most other potent volatile anesthetics) increases coronary blood flow beyond that of the myocardial oxygen demand |
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A method in which there is initiation of a signaling cascade of intracellular events that helps protect the cardiac myocyte and reduce reperfusion myocardial injury following subsequent ischemic episodes |
Preconditioning stimulus such as a brief coronary occlusion |
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How does a volatile anesthetic protects the myocardium |
it mimics ischemic preconditioning which leads to reduced loading of calcium into the myocardial cells during ischemia |
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Preconditioned hearts may tolerate ischemia for how long? compared to the non conditioned hearts |
10mins |
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Why should sulfonylurea oral hyperglycemic drugs be discontinued 24-48hrs prior to elective surgery in high risk cardiac pxs? |
it closes potassium ATP channels thus abolishing anesthetic preconditioning |
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Anesthetic mediated, dose dependent decreases in reflex of sympathetic output are most prominent at ____ MAC of volatile anesthetics |
1 MAC or greater |
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Effect of volatile anesthetic on the tidal volume and respiratory rate. |
Decreased tidal volume and increased RR |
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Effect of volatile anesthetic on the tidal volume and respiratory rate. |
Decreased tidal volume and increased RR |
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All volatile anesthetics have dose dependent increase in RR with the exception of. |
Isoflurane, does not inc RR above 1 MAC |
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True or false. FRC is decreased during general anesthesia. |
True. Dec in intercostal muscle tone |
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Increase in minute ventilation per 1 mmHg increase in PaC02 |
3L/min |
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True or false. All of the inhaled anesthetics produce a dose dependent depression of the ventilatory response to hypercarbia |
True |
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The threshold where respiratory drive ceases is called. |
Apneic threshold (4-5mmHg below the prevailing resting PaC02) |
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Bronchoconstriction under anesthesia can occur as a result from. |
*direct stimulation of the laryngeal and tracheal areas *administration of drugs that cause histamine release *noxious stimuli |
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True or false. Volatile anesthetics and N02 reduce ciliary movement and alter the characteristics of mucus. |
True |
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True or false. N02 and volatile anesthetics cause a small amount of pulmonary vasodilation |
False. N02 inc pulmonary vascular resistance |
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True or false. Volatile anesthetics attenuate hypoxic pulmonary vasoconstriction |
True |
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True or false. Modern day volatile anesthetics are metabolized primarily in the liver. |
False. Primary excretion is via the lungs. |
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2 important actions on neuromuscular function of inhaled anesthetics. |
*directly relax skeletal muscle *potentiate the action of neuromuscular blocking drugs. |
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2 important actions on neuromuscular function of inhaled anesthetics. |
*directly relax skeletal muscle *potentiate the action of neuromuscular blocking drugs. |
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A clinical syndrome of acute, uncontrolled, inc skeletal muscle metabolism. |
Malignant hyperthermia |
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Hallmark findings of Malignant Hyperthermia |
*rapidly rising temp (1deg every 5mins) *inc ETC02 *arrhythmias *mixed respiratory / metabolic acidosis *skeletal muscle rigidity |
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True or false. Suscpetibility to MH is an inherited autosomal recessive genetic disorder |
False. Autosomal dominant |
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A test for mutagenicity and carcinogenicity |
Ames test |
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National institute for occupational safety and health has set exposure limits for N20 and volatile anesthetics. What are the values. |
25 ppm for N20 2 ppm for volatile anesthetics |
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Nitrous oxide dec the activity of what vit b12 dependent enzymes? |
*methionine synthetase - myelin formation *thymidylate synthetase - DNA formation |
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True or false. Desflurane and sevoflurane inhibit the frequency and amplitude of myometrial contractions induced by oxytocin and might delay the onset time of newborn respiration |
True |
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True or false. In terms of neonatal effects from GA, Apgar scores and acid base balance are not affected by anesthetic technique, such as spinal vs GA. |
True |
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The production of compund A from sevoflurane is enhanced by. |
*low flow or closed circuit breathing systems *warm or very dry C02 absorbents |
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True or false. Soda lime produces more compund A than barium hydroxide lime |
False. Barium hydroxide produces more compound A due to higher absorbent temperature during C02 extraction (20 - 32 ppm) |
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Renal enzyme that biodegrades compound A to a toxic thiol. |
Beta - lyase |
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C02 absorbents degrade desflurane, sevoflurane and isoflurane to carbon monoxide when the normal water content of the absorbent is decreased to? |
less than 5% |
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Inhaled anesthetics that are considered safe in MH susceptible pxs. |
N02 and xenon |
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Desflurane and isoflurane contain ____ that is essential for the formation of CO. |
Difluoromethoxy moiety |
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How long should barium hydroxide lime be dried to result in significant CO production from desflurane |
10L/min FGF for 24 hours |
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True or false. Sevoflurane produces more heat than CO in dessicated CO2 absorbents compared to desflurane |
True |
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What differs in the ingredients of sevoflurane from different manufacturers which accounts for the different resistances to degradation when exposed to Lewis acid. |
Water content |
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True or false. Removal of water to the formulation of sevoflurane inhibits the action of Lewis acid (metal halides and metal oxides) to degrade sevoflurane to hydrofluoric acid. |
False. addition of water |
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Metabolism of what volatile anesthetic results in a well described injury to the renal collecting tubules "flouride induced nephrotoxicity" |
Enflurane |
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Volatile anesthetic that is administered by mask as an approach to the difficult adult airway because it preserves spontaneous ventilation and does not cause salivation |
Sevoflurane |
