Lecture Inhalation anesthetic

Which of the following is not a factor affecting the ability to anesthetize a patient care A. CO B. Solubility C. Alveolar to blood partial pressure difference D. FIO2

D. - The factors affecting the ability to anesthetize a patient are: Technical or machine specific: Ventilation Drug related: Solubility of Drug Respiratory: Alveolar to blood partial pressure difference Circulatory: Cardiac Output Tissue related: VRG and Central Compartment The level of anesthesia is related to the alveolar concentration of anesthetic agents, which can be continuously measured or inferred. The concentration or partial pressure of anesthetic in the lungs is assumed to be the same as in the brain, because the drugs are highly lipid soluble and diffusible and quickly reach equilibrium among the the body compartments. Concept of MAC explains how fast a patient is anesthetized or how fast they emerge.

This population is prone to emergence delirium A. Elderly B. Young adult C. Obstetrics D. Children

D. Children - Emergence Phenomenon in Children - Prone to Emergence Delirium Possibly a result of a rapid washout of volatile anesthetic during emergence. It is short in onset and its etiology is unknown. It is self limiting, but a sedative may be given to prevent self harm. Prolongs discharge. Preventive measures include: Quiet emergence environment. Post operative pain management. Adequate premedication (Oral Midazolam). Early reunion of child and parents Administration of small doses of Midazolam*, fentanyl, Propofol or even Dexmedetomidine (Precedex) infusion.

This is associated as a byproduct of sevoflurane and is associated to a potential toxicity development A. Sustance P B. Compound B C. Flouride D. Compound A

D. Compound A - Two by-products of Sevoflurane's degradation in soda lime have been measured in close circuits. 1) fluoromethyl 2,2 difluoro-1 (trifluoromethyl) vinyl ether. AKA COMPOUND A. 2) fluoromethyl 1-2 methoxy2-2difluoro-1 (trifluoromethyl) ethyl ether. AKA Compound B. Compound A has been known to cause proximal corticomedullary tubular necrosis (in rats). Low flows of <1L/min @3-8 MAC hours in healthy patients. (diagram of affected area.) No significant injury has been found in the millions of anesthetics delivered using Sevoflurane.

During the first minutes of gas administration, a higher concentration of the drug than necessary for maintenance, or a loading dose, is delivered to speed initial uptake is called as A. Second gas effect B. Ventilation effect C. Underpressuring D. Concentration effect

D. Concentration effect or overpressuring - After the start on induction and the airway has been established, maintenance of anesthetic gas requires a higher concentration, or loading dose, to ensure adequate anesthetic depth is achieved. This technique is known as overpressuring or the concentration effect. Common technique and is more effective the more soluble the anesthetic. It can speed the effects of slow agents, but has less of an effect on relatively fast agents. After a few minutes, the gas concentration is returned to normal maintenance levels, around 1 MAC of your anesthetic.

An alkane derivative, was introduced into clinical practice by Bryce-Smith and O'Brien in Oxford and Johnstone in Manchester in 1930 A. Chloroform B. Nitrous Oxide C. Diethyl Ether D. Halothane

D. Halothane - By 1930, research focused on the principle of a structure-activity relationship. Divinyl Ether was the first anesthetic developed in this manner. By 1956, Halothane, an alkane derivative, was introduced into clinical practice by Bryce-Smith and O'Brien in Oxford and Johnstone in Manchester. Compared to Diethyl/Divinyl Ether, Halothane was everything and more.

Halothane hepatitis is associated with decreased morbidity and moderately increase concentrations of serum A. Glutathione (GSH) B. Glutathione-S-transferases (GSTs)

A. - 2 Presentations of Halothane Hepatitis. 1) mild reaction that occurs secondary to a direct hepatic effect OR following reductive metabolism of Halothane. Halothane Hepatitis is common in adults but children are affected as well. Associated with decreased morbidity and moderately increase concentrations of serum glutathione S transferase (GST) or transient jaundice. Glutathione (GSH) and glutathione-S-transferases (GSTs) are two primary lines of defense against both acute and chronic toxicities of electrophiles and reactive oxygen/nitrogen species. GSH confers cellular protection by directly or enzymatically reducing free radicals and reactive species (RS), and conjugating endogenous and exogenous electrophiles. GSTs are a superfamily of Phase 2 detoxification enzymes that detoxify both RS and toxic xenobiotics, primarily by catalyzing GSH-dependent conjugation and redox reactions

Determine the Anesthetic based on the Blood/gas partition coefficient A. 0.6 B. 1.4 C. 0.47 d. 0.42

A. 0.6- Sevoflurane B. 1.4- Isoflurane C. 0.47- Nitrous oxide d. 0.42- Desflurane

Which of the following is more prone to induce arrhythmia A. 5 halogens B. 6 halogens

A. 5 halogens - Arrhythmogenic Properties - 5 Halogens are prone to induce arrhythmias vs. ethers with 6 Halogens.

Identify the following MAC in 1 atm and in 60-70% N2O A. 6/ 2.38 B. 2/ 0.66 C. 1.17/ 0.56 D. 104

A. 6/ 2.38- Desflurae B. 2/ 0.66- Sevoflurane C. 1.17/ 0.56- Isoflurane D. 104- Nitrous Oxide

The maximum difference of an alternating electrical current. A. Amplitude B. Latency C. Potential D. Suppression

A. Amplitude -Amplitude-the maximum difference of an alternating electrical current.

Potency is __________ proportional to lipid solubility A. Directly B. Inversely

A. Directly Potency=Lipid Solubility DIRECTLY correlates to lipid solubility or oil/gas partition coefficient values.

Which of the following are unfavorable characteristics of diethyl ether A. Caused excessive secretions during inhalation inductions. B. Incidences of laryngospasms C. Excessive depths of anesthesia. D. Too light of anesthesia

A ,B, C Diethyl ether Caused excessive secretions during inhalation inductions. Incidences of laryngospasms Excessive depths of anesthesia.

Which of the following can possibly trigger malignant hyperthermia A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

A, B, C, E - All volatile agents are capable of triggering malignant hyperthermia. The only one that is not a trigger? Incidence is 1:100,000 surgeries in adults and 1:30,000 in children. The depolarizing muscle relaxant Succinylcholine IV/IM is also a trigger. Goal is early detection in the preoperative interview so preparations can be initiated prior to administration of general anesthesia.

These are weak in causing an increase in HR and are frequently used in excess of 1 MAC. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

A, E - Heart Rate Volatile anesthetics and N2O induce changes in HR relative to the concentration of the anesthetic being used. Affects HR by way of: Antagonism of SA node automaticity. Modulation of baroreceptor reflex activity. SNS stimulation via activation of tracheopulmonary and systemic receptors. Halothane/Sevoflurane are weak in causing an increase in HR and are frequently used in excess of 1 MAC. Overpressuring from 0.5MAC to 2.9MAC may increase plasma concentration of epinephrine.

Trifluoroacetyl Chloride binds to which organ to form trifluoroacetylated proteins or neoantigens. A. Lungs B. Kidneys C. Brain D. Liver

D. Liver - 2 Presentations of Halothane Hepatitis. 2) Fulminant Hepatic Failure Multiple exposures High mortality rate Immune response evokes this syndrome. Oxidative metabolism of halothane by hepatic cytochrome p450 releases an unstable intermediate Trifluoroacetyl Chloride. Binds to liver proteins to form trifluoroacetylated proteins or neoantigens. Some patients develop antibodies to TFA protein. Subsequent exposures to Halothane develop and immune response and causes hepatic necrosis TFA antibodies occur in 70% of patients with Fulminant Hepatic Failure.

Which of the followng anesthetic does not decrease MAP A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide

D. Nitrous Oxide - All alter hemodynamics! More importantly, all reduce MAP and CO and CI in a dose dependent manner by decreasing SVR (Least affected by Sevoflurane) Halothane causes less disruption in inherent vascular tone, and decreases MAP by DIRECT myocardial depression vs a reduction in preload. N2O activated the sympathetic nervous system and INCREASES SVR which can lead to increased ICP. Generally speaking, N2O used in combination with inhalationals increases SVR and helps support BP.

In a patient with existing pulmonary hypertension, this agent will dramatically increase PVR due to the constriction of the pulmonary vascular smooth muscle. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

D. Nitrous Oxide - In a patient with normal pulmonary vascular resistance (PVR), the addition of N2O will slightly increase PVR. This can quite possibly be a result from the increase in SNS tone. In a patient with existing pulmonary hypertension, N2O will dramatically increase PVR due to the constriction of the pulmonary vascular smooth muscle. Volatile anesthetics and even Desflurane at 0.8-1.2 MAC will decrease Pulmonary Artery Pressure (PAP) but at high MAC levels, it produces the opposite effect around 1.6MAC. Unrealistic, right?

It has been found that repeated exposure to this agent can lead to inactivation of VitB12. component of methionine synthetase, which can disrupt DNA synthesis. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

D. Nitrous Oxide - Nitrous Oxide Metabolized in the intestinal flora by only minimally (0.004%) and yields molecular nitrogen. It has been found that repeated exposure to N2O can lead to inactivation of VitB12. component of methionine synthetase, which can disrupt DNA synthesis. Use caution in patients that are pregnant, patients that receive general anesthesia more than once a week, or patients that are debilitated and have problems with wound healing.

Least potent of the anesthetic gases A. Desflurane B. Sevoflurane C. Isoflurane D. Nitrous Oxide

D. Nitrous Oxide - Wait! Why is N2O's MAC 104? The dose of an inhaled anesthetic gas is expressed as its percent in the inspired mixture. In an effort to compare the relative potencies of anesthetic gases, anesthesia providers have accepted a measure known as MAC, or minimum alveolar concentration. It is analogous to the ED-50 (effective dose for 50% of patients) expressed in milligrams for other drugs. Nitrous oxide is clearly the least potent of the anesthetic gases, having a MAC of 104. This was extrapolated from studies conducted in a hyperbaric chamber because its MAC cannot be achieved at normal atmospheric pressure.

The disadvantages of this inhalation anesthetic include: Expansion of closed air spaces, Requires high concentrations, Amount of oxygen delivered is reduced, Diffusion hypoxia, increase in teratogenicity, PONV, Supports combustion & Immune suppression A. Isoflurane B. Desflurane C. Sevoflurane D. Nitrous Oxide

D. Nitrous Oxide Advantages: Nitrous oxide Analgesia Rapid uptake and elimination Little cardiac or respiratory depression Nonpungent Reduces MAC or the more potent agents Minimal biotransformation Disadvantages Expansion of closed air spaces Requires high concentrations Amount of oxygen delivered is reduced Diffusion hypoxia, increase in teratogenicity, PONV Supports combustion Immune suppression -

The most recent and widely used anesthetic (1995) A. Isoflurane B. Desflurane C. Halothane D. Sevoflurane E. Enflurane F. Methoxyflurane

D. Sevoflurane Anesthetic Year(s) Anesthetic Properties Demonstrated/Introduced Ether (Crawford Long) 1842 N2O (Horace Wells) 1845 Chloroform (James Simpson) 1847 Cyclopropane 1934 Fluroxene 1951 Halothane 1956 Methoxyflurane 1960 Enflurane 1973 Isoflurane 1981 Desflurane 1993 Sevoflurane 1995 Xenon??? ????

This theory proposed that all inhalation anesthetics work via a similar (undefined) mechanism of action, but not necessarily at the same site of action. A. Meyer-Overton theory B. Lipid Theory C. Pauling-Miller Theory D. Unitary Hypothesis

D. Unitary Hypothesis - Unitary Hypothesis: "Properties of anesthetics must be taken into account when developing a theory that attempts to explain their mechanism of action." What does this mean? It means we don't know how it really works

A professor of surgery in Chicago, can be credited with the modern use of N2O A. Humphrey Davis B. William Morton C. Crawford Long D. Charles Jackson E. Edmund Andrews

E. Edmund Andrews - In 1868, Edmund Andrews, a professor of surgery in Chicago, can be credited with the modern use of N2O. He declared a safer anesthetic could be achieved by combining oxygen with N2O. Previously, N2O was delivered through a mouthpiece and nose clamp to prevent the rebreathing of air. One problem though...Diffusion Hypoxia! Results from the dilution of alveolar oxygen concentration by the large amount of nitrous oxide leaving the pulmonary capillary blood at the conclusion of nitrous oxide elimination. Can be prevented by filling the patient's lungs with oxygen at the conclusion of nitrous administration.

Hepatocyte Hypoxia due to causes an increase in reductive metabolism has been linked to A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

E. Halothane - All volatile anesthetics reduce total hepatic flow. Halothane produces the greatest reduction. Conversely, Iso/Sevo/Des have been shown to increase or maintain hepatic artery blood flow, and cancels out any accompanying decrease in portal vein flow. Hepatocyte Hypoxia causes an increase in reductive metabolism (doesn't occur with ether based anesthetics) of Halothane which ahs been linked to "Halothane Hepatitis". Simply, it is hepatic damage following the administration of Halothane.

Which of the following is not an appropriate step to take in Preparation for MH/MH susceptible patient A. Take off those vaporizers and keep them out of the room! B. Lock up the Sux! C. Change the CO2 Absorber. D. Change the anesthesia circuit. E. Apply charcoal filters to Inspiratory and Expiratory limbs. F. Flush the anesthesia machine with Oxygen for more than 10 minutes. G. TIVA setup

F. - Malignant Hyperthermia - Preparation for MH/MH susceptible patient Take off those vaporizers and keep them out of the room! Lock up the Sux! Change the CO2 Absorber. Change the anesthesia circuit. Apply charcoal filters to Inspiratory and Expiratory limbs. Flush the anesthesia machine with Oxygen for more than 20 minutes. TIVA setup

Incremental increases in MAC _________ predict with any precision the influence on respiratory or cardiovascular function. A. Does not B. Does

A. Does not Finally, it must be emphasized that MAC is a measure of the dose response for an inhalation agent in producing anesthesia. Incremental increases in MAC do not predict with any precision the influence on respiratory or cardiovascular function. For example, 0.5 MAC of an inhalation agent does not necessarily produce half the influence on blood pressure that is produced by 1.0 MAC. A provider cannot simply rely on the MAC number to assess adequacy of anesthesia. Administration of muscle relaxants will abolish any purposeful movement entirely. To determine light planes of anesthesia other assessments must also be employed. HR, BP can be masked by Beta Blockers. Pupil size can be affected by opioids.

Volatile Anesthetic _______ latency and __________ amplitude and can indicate ischemia or a result of the anesthetic agent. A. Increase; decrease B. Decrease; increase C. Increase; increase D. Decrease; decrease

A. Increase; decrease - Volatile Anesthetic increase latency and decrease amplitude and can indicate ischemia or a result of the anesthetic agent. Isoflurane has been shown to cause the greatest reduction in cortical somatosensory evoked potential (cSSEP) amplitude.

An ___________ CO removes more anesthetic from the lungs, which slows the rise in lung and brain concentration. A. Increased B. Decreased

A. Increased - Circulatory Factors 2) Counter intuitively, increases in cardiac output slow onset. The more soluble the agent, the slower the onset. An increased CO removes more anesthetic from the lungs, which slows the rise in lung and brain concentration. *The longer the anesthetic is delivered the less of an effect this has.

With inhalation anesthetics, Apneic Threshold is _________. A. Increased B. Decreased

A. Increased - Emergence continued Apneic Threshold is increased. The magnitude or intensity that must be exceeded for a certain reaction, phenomenon, result, or condition to occur or be manifested. Higher PaCO2 values are required to initiate spontaneous ventilation. You will have to consider other factors as well to elicit this response at emergence. These variables include, adequate reversal, opioid administration, even excessively high ETCO2 values will cause somnolence and mimic inadequate VA elimination. Inhalation Inductions Halothane, N2O, and Sevoflurane are most commonly used. They decrease the incidence of breath holding, secretion production and laryngospasm occurrence.

Anesthetic Potency ______________ when a lower Atomic Mass Unit (AMU) is replaced with a heavier halogen. A. Increases B. Decreases

A. Increases - Anesthetic Potency Increases when a lower Atomic Mass Unit (AMU) is replaced with a heavier halogen. Ex. Fluorine (19 AMU) for Bromine (80 AMU). Adding F to ether changes properties where it becomes more potent becomes a strong convulsant becomes inert at full fluorination.

Advantages of this inhalation anesthetic include: inexpensive, decrease cerebral metabolic rate, no significant systemic toxicity. Disadvantages includeL pungent oder, airway irritant, slower induction and emergence, trigger for malignant hyperthermia A. Isoflurane B. Desflurane C. Sevoflurane D. Nitrous Oxide

A. Isoflurane Advantages: Moderate muscle relaxation Decreases cerebral metabolic rate Minimal biotransformation No significant systemic toxicity Inexpensive Possible neuro- and cardiac protection Disadvantages Pungent odor Airway irritant Trigger for malignant hyperthermia Slower induction and emergence Trigger for malignant hyperthermia

_______ flows of O2 during induction will not deliver the proper concentration of anesthetic gas to ensure loss or consciousness. A. Low B. High

A. Low - Factors that may affect the speed of uptake early in the administration of volatile anesthetics: 1) Drug solubility in the rubber and plastic machine parts. Theoretically can retain small quantities of anesthetic gases and slow the administration to the patient at the start of anesthetic delivery. Affect on uptake is minimal and ceases after 15 minutes of administration. Knowing that sequestration of the small amount anesthetic gases within the machine can have serious implications especially those susceptible to Malignant Hyperthermia. 2) Total machine liter flow of the gases chosen. Low flows of O2 during induction will not deliver the proper concentration of anesthetic gas to ensure loss or consciousness.

Defined as the Minimal Alveolar Concentration at equilibrium at 1 atmosphere, which 50% of subjects will not respond to a surgical stimulus. A. MAC B. MAC-awake C. MAC-BAR

A. MAC - Defined as the Minimal Alveolar Concentration at equilibrium at 1 atmosphere, which 50% of subjects will not respond to a surgical stimulus. Response is defined as "gross, purposeful movement of the head or extremities."

This theory states that Lipid Solubility is directly proportional to potency A. Meyer-Overton theory B. Lipid Theory C. Pauling-Miller Theory D. Unitary Hypothesis

A. Meyer-Overton theory - 1) Lipid Solubility is directly proportional to potency (Meyer Overton Rule). 2) Reversal of anesthetic effect can be achieved with the application of pressure with some exceptions. 3) No common chemical structure for the variety of compounds is capable of producing anesthesia. 4) The molecular and structural changes responsible for producing anesthesia must occur within seconds and be reversible. 5) A reduction in body temp lowers anesthetic requirements.

Suggests that anesthesia is produced by the volume of anesthetic molecules present (dissolved) at the site, not by the type of volatile agent present. A. Meyer-Overton theory B. Lipid Theory C. Pauling-Miller Theory D. Unitary Hypothesis

A. Meyer-Overton theory - Suggests that anesthesia is produced by the volume of anesthetic molecules present (dissolved) at the site, not by the type of volatile agent present. - Research leans towards the idea that the mechanism of action is not unitary, but affects multiple anatomic regions of the body and causes molecular changes. Spinal Cord- mediates immobility to painful stimulus via several mechanisms: Tandem-pore-domain, weak-inward-rectifying K+ channels (TWIK) Gamma aminobutyric acid type A receptors (GABAA)

Which of the following has a faster rise A. Nitrous Oxide B. Desflurane

A. Nitrous Oxide

In the past, surgeons encouraged these staff to become anesthetists A. Nurses B. Junior doctors C. Students D. Technician

A. Nurses - Occasional Anesthetists The early days of anesthesia was not prestigious or glamorous. Low pay Sole responsibility Satisfied with the subordinate role have natural aptitude and intelligence to provide a smooth anesthetic and relaxation the surgeon demanded. As a result, surgeons encouraged new graduate nurses to train as anesthetists.

All inhalation anesthetics undergo ________ by way of hepatic metabolism. A. Oxidation B. Reduction C. Hydrolysis D. Conjugation

A. Oxidation - Biodegredation - All inhalation anesthetics undergo oxidation by way of hepatic metabolism. Oxidation is a phase 1 reaction where O2 is introduced into the molecule or the oxidative state of a molecule is changed so that the its relative oxygen content is increased. The molecule is split; one atom oxidizes each molecule of drug, and the other is incorporated into a molecule of water. This loss of electrons results in Oxidation.

Initiated by volatile anesthetics that results in a cascade of intracellular events that help protect the myocardium from ischemic and reperfusion insult.. A. Preconditioning B. Postconditioning C. Periconditioning

A. Preconditioning - Preconditioning Initiated by volatile anesthetics that results in a cascade of intracellular events that help protect the myocardium from ischemic and reperfusion insult.. It is multifactorial. Improves contractile function. Prevents down regulation of major sarcoplasmic reticulum Ca2+ cycling proteins. Down Regulation- desensitization due to continued exposure. Why is this important? An increase in Ca2+ causes hypertension and decreases stress of myocardium cells. Sevoflurane has been found to show late preconditioning 24-48hrs after exposure. Insulin and adenosine are also cardio protective.

The longer and anesthetic is given, the more the central compartment is _______. A. Saturated B. Unsaturated

A. Saturated - Circulatory Factors The cardiovascular system influences the anesthetic uptake in 2 ways 1) The blood leaving the lungs with anesthetic is normally distributed to the vital organs or high-blood-flow areas, AKA the vessel rich group or central compartment. The VRG consists of the heart, liver, kidneys, and brain receive proportionately more anesthetic sooner than muscle or fat areas. The longer and anesthetic is given, the more the central compartment is saturated.

Simultaneous administration of a relatively slow agent such as isoflurane and a faster drug such as nitrous oxide (in high concentrations) can speed the onset of the slower agent and is called as A. Second gas effect B. Ventilation effect C. Underpressuring D. Concentration effect

A. Second gas effect - The simultaneous administration of a relatively slow agent like Isoflurane and a faster onset drug such as N2O (in high concentrations) can speed the onset of the slower agent. The speed at which N2O is absorbed in the alveoli and taken up into the capillary circulation is relatively fast. With the coadministration of a slower anesthetic, the Sevoflurane molecules for example, are able to "draft" off of the faster N2O.

Most potent inhalation agent that cause potentiation of NMB A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

A. Sevoflurane - All volatile anesthetics produce a dose-dependent relaxation of skeletal muscle as well as potentiation of the effects of depolarizing and nondepolarizing muscle relaxants. This happens by a reduction in neural activity within the CNS and presynaptic or postsynaptic effect at the neuromuscular junction. Predominantly affect the postjunctional membrane. By order of potentiation: Sevo>Iso=Des*>Halothane. Just know that volatile anesthetics can delay the time to adequate reversal and as the anesthetist, you should be cognizant of the outcome when muscle relaxants are used in combination.

This has been found to show late preconditioning 24-48hrs after exposure. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

A. Sevoflurane - Sevoflurane has been found to show late preconditioning 24-48hrs after exposure.

This agent hase average metabolism of 3-6% A. Sevoflurane B. Nitrous oxide C. Isoflurane D. Desflurane

A. Sevoflurane - The body metabolizes Inhalational Anesthetics in varying degrees.

This theoretically can cause nephrotoxicity A. Sevoflurane B. Nitrous oxide C. Isoflurane D. Desflurane

A. Sevoflurane The body metabolizes Inhalational Anesthetics in varying degrees. N2O, Desflurane, and Isoflurane are the least metabolized and do not result in metabolism related toxicity. Halothane can cause hepatotoxicity and Sevoflurane theoretically can cause nephrotoxicity which will be discussed in the next lecture.

Which can be used in conjunction with inhalation anesthetic A. NMB B. Opioid C. LA D. Antiemetics

All of the above - In the early use of anesthetics, only 1 anesthetic was responsible for covering the whole anesthetic regimen. We have since learned that a combination of techniques could be used to provide a complete anesthetic state. IV drugs can be employed in conjunction with inhalation anesthetics. Opioids, neuromuscular blocking agents, local anesthetics and antiemetics. This evolved technique allows the anesthesia provider to use smaller, and more easily manipulated doses of specific receptor agonist and antagonists. We are able to predict the outcome of specific drugs to have the desired effect based on need of the surgeon, expected outcome of the surgery, and how well the patient will emerge from anesthesia

Hyperventilation and decreasing the PaCO2 to around _______mmHg will aid to "reduce brain bulk," or "shrink the brain." A. 20-25 B. 25-30 C. 30-35 D. 35-40

B. 25-30 - Normal response to Hypocapnia: Vasoconstrict Normal response to Hypercarbia: Vasodilate Think of it this way, the surrounding tissue that is supplied by vessels are starving for air, they want more blood, so they vasodilate. This is helpful in neurosurgical procedures. Hyperventilation and decreasing the PaCO2 to around 25-30 mmHg will aid to "reduce brain bulk," or "shrink the brain." In other words, you are decreasing the size of the brain that is in a fixed space by decreasing CBF.

Which of the following does not increase MAC A. Red hair in femailes B. Acute alcohol abuse C. Hyperthyroidism D. Stimulant drugs

B. Acute alcohol abuse Factors That Increase MAC • Young age • Hyperthermia • Hyperthyroidism • Hypernatremia • Acute administration of CNS stimulant drugs • Red hair in females • Chronic alcohol abuse

Volatile anesthetics also cause an __________ of SSEP signals necessary for neurophysiology monitoring of the anesthetized patient. A. Stimulation B. Attenuation

B. Attenuation - Pertaining to neurosurgical patients, delayed emergence is not desirable as it delays initial post operative neurological assessment. Use of Total IntraVenous Anesthesia (TIVA) is a common technique to ensure that a rapid emergence and thus assessment of the patient post procedure can be properly conducted. Propofol with Remifentanil or Sufentanil is employed here at Jefferson for spine cases, and neurosurgical procedures. Volatile anesthetics also cause an attenuation of SSEP signals necessary for neurophysiology monitoring of the anesthetized patient.

Volatile Anesthetics produce a dose related suppression of EEG activity with an initial _________ in amplitude and _____________ frequency. A. Increased; increased B. Increased; decreased C. Decreased; decreased D. Decreased; increased

B. Increased; decreased - Volatile Anesthetics produce a dose related suppression of EEG activity with an initial increase in amplitude (later a decline) and decreased frequency. At high concentrations, electrical activity is silenced. Volatile anesthetics alter reading or monitoring of the cortical regions of the brain. Iso, Sevo, Des, N2O produce a dose dependent reduction in evoked potentials. Tests the electrical activity of the brain in response to stimulation of specific sensory nerve pathways.

This term is the time between the initiation of a peripheral stimulus (e.g., electrical stimulation of the median nerve at the wrist) and onset of the evoked potential (e.g., cortical) recorded by scalp electrodes A. Amplitude B. Latency C. Potential D. Suppression

B. Latency - Latency-the time between the initiation of a peripheral stimulus and onset of the evoked potential recorded by the scalp electrodes.

Gases that have a _____ solubility in blood and adipose tissue achieve tensions and equilibrate more rapidly A. High B. Low

B. Low

The higher the number of Fluorine atoms, the __________ the biodegradation. A. Higher B. Lower

B. Lower - The higher the number of Fluorine atoms, the lower the biodegradation. Rates of Metabolism of Anesthetic Agents Sevoflurane (Ultane) 5-8% (Fluorinated methyl isopropyl ether) Isoflurane (Forane) 0.2% (1-chloro-2,2,2-Trifluoroethyl difluoromethyl ether) Desflurane (Suprane) 00.2% (Fluorinated methyl ethyl ether) Halothane 12-25%

Defined as 50% of patients will respond to "open your eyes". A. MAC B. MAC-awake C. MAC-BAR

B. MAC-awake Mac Awake 50% of patients will respond to "open your eyes". Also 1/3 of MAC value.

In 1800, Humphrey Davy used self-experimentation to study the effects of A. Chloroform B. Nitrous Oxide C. Diethyl Ether D. Halothane

B. Nitrous Oxide - 1800, Humphrey Davy used self experimentation to study the effects of Nitrous Oxide (N2O). - He discovered that it made him feel dizzy and euphoric. Wanting to share in his fondness for the gas, he encouraged his friends to inhale the gas with him and found that their inhibitions were lowered and their feelings of happiness or sadness intensified. - Poet Robert Southey, a friend of Davy, referred to his experience as being "turned on" and nitrous oxide became known as "Laughing Gas". - Beyond Davy's circle, nitrous oxide parties became a fad among the wealthy. - He also predicted that N2O could be used for surgical operations.

All commonly used anesthetic agents use which configuraiton A. R-O-H B. R-O-R C. NH3 derived

B. R-O-R - An understanding of the chemical structure of inhalation agents provides insight into their physical properties (e.g., flammability). However, the relationship between the pharmacologic characteristics (e.g., arrhythmogenic properties) and chemical structure of agents is not as predictable. All commonly used anesthetic agents use the R-O-R Ether configuration. "R" refers to an Alkyl group.

Althouh recently found no statistical significance, this inhalation anesthetics is still recommended to be cautiously used with people that have renal insufficiency A. Isoflurane B. Sevoflurane C. Nitrous Oxide D. Desflurane

B. Sevoflurane - Sevoflurane and its effect on kidneys is well documented. The FDA recommends caution in patients with renal insufficiency (Creatinine >1.5mg/dL) The real danger is with Sevoflurane and soda lime. Soda Lime is made up of either potassium hydroxide (KOH) or Sodium Hydroxide (NaOH). Additives like ethyl violet are added Remains white when fresh Turns purple when exhausted. Breaks down all modern day inhalational anesthetics. Bonus Question: What size are the granules? - The size of the soda lime granules is 4-8 mesh (i.e. will pass through a mesh of 4-8 strands per inch in each axis or 2.36-4.75 mm

These have shown to produce a coronary steal. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

C & B - Isoflurane an Desflurane have shown to produce a coronary steal. Iso/Des/Sevo all produce coronary vasodilation, but Sevoflurane produces the least. - Can be present in a hypotensive situation, untreated, or with vasodilating drugs like Sodium Nitroprusside or Nitroglycerin IV. Reversed if normotension is reestablished. Drugs like Persantine and Dipyridamole and adenosine cause coronary vasodilation even in the presence of normotension.

This inhalation agents can increase HR A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

C & B - Isoflurane and Desflurane can increase HR Desflurane's effect on HR can also be seen without over pressurization. Pretreatment with fentanyl 5 minutes before an increase in end tidal Desflurane concentration from 4-8% modulates/attenuates the increase in HR by 61% and 70% respectively. MAP is also attenuated 31%-46% respectively as well. Use of Esmolol can counteract the effects of Desflurane induced tachycardia but not blood pressure at 0.75mcg/kg IV.

Where is the anesthetic effect of immobility site of action (SATA) A. Cerebellum B. Medulla C. Spinal Cord D. Cerebral GABA

C & D - Spinal and cerebral GABAA receptors were shown to contribute to volatile anesthetic's ability to produce immobility and can be concluded that the anesthetic effect of immobility is modulated at the spinal cord and supraspinal level. Other sites of affected by volatile anesthetics include the reticular formation within the brainstem, cerebral cortex and hippocampus. Deeper levels of anesthesia produce "burst suppression" and eventually a flat EEG. On a molecular level, researchers have found that the most likely site of action of volatile anesthetics involves interactions with the membrane protein in specific receptors and not perturbation (disturbance caused by secondary influence) of lipid bilayers.

Which of the following decrease the response of hypoxic pulmonary vasoconstriction A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

C, E, & D Hypoxic Pulmonary Vasoconstriction It is a normal physiologic response to hypoxia or atelectasis. Isoflurane and Halothane decrease this response. N2O greatly decreases this response. Reduces the flow of desaturated blood through underventilated areas of the lung.

This refers to the reduction of perfusion of ischemic myocardium with simultaneous improvement of blood flow to non ischemic tissue A. Diffusion hypoxia B. Paradoxical hypotension C. Coronary steal syndrome D. Robin hood syndrome

C. - Coronary steal syndrome- reduction of perfusion of ischemic myocardium with simultaneous improvement of blood flow to non ischemic tissue AKA Reverse Robin Hood Syndrome. Has been demonstrated to occur more easily with "coronary steal prone anatomy" i.e. multivessel disease, CAD. Isoflurane an Desflurane have shown to produce a coronary steal. Iso/Des/Sevo all produce coronary vasodilation, but Sevoflurane produces the least.

Which of the following is true regarding Respiratory System and Inhalational Anesthetics A. Increase TV B. Increase RR C. Decrease responsiveness to CO2

C. - Volatile anesthetics exert a dose-response effect primarily on Tidal Volume (TV). Responsiveness to CO2 is depressed and the TV reduces as concentration of the agents are increased. To counteract the hypercarbia, RR increases as well. Unfortunately, the TV of each breath is not sufficient enough to decrease the PaCO2. Fortunately, the surgical stimulation helps overcome the respiratory -depressant effects of volatile agents. Emergence Can be associated with hypercarbia if Mv is not adequately supported and owes to the volatile anesthetic capacity to depress the ventilatory response to PaO2 and PaCO2.

that immobility (anesthetic effect) is attenuated or lost if the chain exceeds a distance of _____ carbon atoms A. 1-2 B. 2-3 C. 4-5 D. 5-6

C. 4-5 Ether anesthetics: - Straight chained or branched "nonaromatic" hydrocarbons with no more than 4 Carbon atoms. Its length is significant in that immobility (anesthetic effect) is attenuated or lost if the chain exceeds a distance of 4-5 Carbon atoms (5 Angstroms) The molecular shape of these agents is spherical or cylindrical with a length less than 1.5 times its diameter.

Which of the following is an effect of inhalation anesthetic to the kidneys A. Increase Urinary output B. Increase GFR C. Decrease Renal vascular resistance D. Increase Systolic BP

C. Decrease Renal vascular resistance - Auto regulation of the renal circulation remains intact during anesthesia. When SBP decreases, the kidneys compensate by decreasing renal vascular resistance. Though compensatory mechanisms remain intact, GFR may still decline. The result is a commonly observed decline in UO intraoperatively. 0.5cc/kg.

Crawford Long used___________ or the removal of a small cyst in Jefferson, Georgia in March 1842. He unfortunately did not report his findings. A. Chloroform B. Nitrous Oxide C. Diethyl Ether D. Halothane

C. Diethyl Ether - Crawford Long used diethyl ether for the removal of a small cyst in Jefferson, Georgia in March 1842. He unfortunately did not report his findings. Charles Jackson and Horace Wells both experimented with ether and N2O. William T.G. Morton, a Boston dentist on October 16, 1846 "conclusively" demonstrated the use for ether in surgical anesthesia in the "Ether Dome" or modern day Operating Room at Massachusetts General. John Collins, a visiting surgeon exclaims "This is no humbug!" "I have seen something today that will go around the world!"

Was considered the earliest "complete" anesthetics A. Chloroform B. Nitrous Oxide C. Diethyl Ether D. Halothane

C. Diethyl Ether - Diethyl Ether was considered the earliest "complete" anesthetics. Tolerated for more than 90 years and fell out of service due to numerous unfavorable characteristics: Caused excessive secretions during inhalation inductions. Incidences of laryngospasms Excessive depths of anesthesia.

The discovery of _____________ greatly affected the development of volatile (inhalational) anesthetics. A. Oxygenation B. Hydrogenation C. Halogenation D. Alkalinization

C. Halogenation - The discovery of halogenation greatly affected the development of volatile (inhalational) anesthetics. The additions of Bromine (Br), Chlorine (Cl), Fluorine (Fl), and Iodine (I) influences whether an anesthetic agent was potent, arrhythmogenic, flammable, or chemically stable.

This inhalation anesthetic negative effect A. Isoflurane B. Desflurane C. Halothane D. Sevoflurane E. Enflurane F. Methoxyflurane

C. Halothane - Hepatotoxic Arrhythmogenic

This inhalation anesthetic Sweet Smelling Non Flammable High Potency A. Isoflurane B. Desflurane C. Halothane D. Sevoflurane E. Enflurane F. Methoxyflurane

C. Halothane Sweet Smelling Non Flammable High Potency

What property of isoflurane, desflurane, and sevoflurane prevents them to cause hepatic damage that can lead to hepatic disease A. Hydrophobicity B. Lipophilicity C. Increase Flourination D. Increase methylation

C. Increase Flourination - Halothane Hepatitis continued... It is extremely rare for Iso/Des/Sevo to produce clinically significant liver damage despite isolated cases attributing Desflurane and Sevoflurane as causing fulminant liver failure. Their molecular structure (increased fluorination) resists hepatic degradation, and their pharmacodynamic profile is associated with no changes or slight reductions in hepatic blood flow.

Which of the following is not a sign of malignant hyperthermia A. Hypoxia B. Tachycardia C. Hypercapnia D. Muscle flaccidity

D.

Which of the following does have an influential effect on MAC A. Hypertension B. Hypotension C. Hypercapnia D. Hypocapnia

B. Hypotension Factors with No Effect on MAC • Duration of anesthesia • Gender • Hypocapnia and hypercapnia • Metabolic alkalosis • Hypertension • Hyperkalemia or hypokalemia • Administration of propranolol, isoproterenol, promethazine, naloxone, aminophylline, and neuromuscular blocking agents.

Which agents when used with soda lime cause the greatest amount of CO production. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

B & C - Desiccated soda lime and BaralymeTM have been shown to cause fires and patient injury because the reaction by which CO2 is neutralized, is an exothermic reaction. Desflurane and Isoflurane used with soda lime cause the greatest amount of CO production.

These agents both have similarities to Halothane in that they each possess a common metabolic pathway via CYP p450 that eventually yields TFA molecules. The rate of biodegradation is the difference. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

B & C - Halothane Hepatitis continued... Cytochrome P450 2E1 is the predominant isoform responsible for the oxidation of halothane. Obese patients have an greater occurrence of fatty liver infiltration it is observed that this population has a greater quantity of CYP 450 2E1. The overall incidence of the fulminant form of halothane hepatitis is 1:35,000 anesthetics. Isoflurane and Desflurane both have similarities to Halothane in that they each possess a common metabolic pathway via CYP p450 that eventually yields TFA molecules. The rate of biodegradation is the difference. Isoflurane is metabolized at a rate of 100x less than Halothane which means the incidence of Halothane Hepatitis is 1:3,500,000 anesthetics.

Flammability can be reduced by substituting hydrogen atoms with A. Oxygen B. Fluorine C. Bromine D. Chlorine

B, C, D - Flammability can be reduced by substituting hydrogen atoms with Halogens (Br, Cl, F, I). May 6th 1937, Lakehurst, New Jersey... "Oh, the humanity!"-Herbert Morrison - Flammability can be reduced by substituting hydrogen atoms with Halogens (Br, Cl, F, I). Best Example: Desflurane Contains F as its only Halogen (6) Strongly resists degradation Metabolized 1/10 as much as Isoflurane.

Which of the following describes the ventilation effect A. The faster and more deeply a patient breathes or is ventilated, the slower the patient loses consciousness at the start of anesthesia and emerges at the end B. The faster and more deeply a patient breathes or is ventilated, the faster the patient loses consciousness at the start of anesthesia and emerges at the end C. The slower and more shallow a patient breathes or is ventilated, the slower the patient loses consciousness at the start of anesthesia and emerges at the end D. All of the above

B. - Continuous inhalation administration of the agent into the lungs promotes subsequent diffusion into the blood and tissues as the anesthetic progresses. Anesthetic uptake slows throughout the surgical procedure. The faster and more deeply a patient breathes or is ventilated, the faster the patient loses consciousness and emerges at the end of the procedure, AKA ventilation effect. Poor lung function or V/ Q deficits hinders inhalation anesthetic administration. Rapid acting (low blood/gas solubility) agents are affected by these deficits to a greater extent than high/blood gas solubility agents. Increasing the concentration of insoluble agents or increasing ventilation with soluble drugs.

Which of the following is true A. Lipid Solubility is indirectly proportional to potency (Meyer Overton Rule). B. Reversal of anesthetic effect can be achieved with the application of pressure with some exceptions. C. There is common chemical structure for the variety of compounds is capable of producing anesthesia. D. The molecular and structural changes responsible for producing anesthesia must occur within minutes and be reversible. E. A reduction in body temp increases anesthetic requirements.

B. - Pharmacodynamics: Mechanism of Action - 1) Lipid Solubility is directly proportional to potency (Meyer Overton Rule). 2) Reversal of anesthetic effect can be achieved with the application of pressure with some exceptions. 3) No common chemical structure for the variety of compounds is capable of producing anesthesia. 4) The molecular and structural changes responsible for producing anesthesia must occur within seconds and be reversible. 5) A reduction in body temp lowers anesthetic requirements.

Which of the following is true regarding CNS and Inhalational Agents A. Increase CMRO2 B. CBF is variable C. Halothane decreases CBF

B. CBF is variable Cerebral Metabolic Rate of O2 Consumption (CMRO2) In a dose dependent manner, volatile anesthetics decrease CMRO2. Cerebral Blood Flow "Variable" depending on who you choose to believe. Halothane increases CBF. Cerebral Autoregulation The maintenance of constant cerebral blood flow despite changes in cerebral perfusion pressure, where CPP is equivalent to MAP-ICP (or CVP, whichever is greater). Given that normal ICP is generally low (5-12 mmHg), CPP is mainly dependent upon MAP. The normal range of cerebral autoregulation is often quoted between MAPs of approximately 60-160 mmHg, keeping in mind some sources will define the range of cerebral autoregulation in terms of CPP. Cerebral Vascular Resistance When decreased, Cerebral Blood Flow (CBF), Cerebral Blood Volume (CBV), and Cerebral Spinal Fluid Production (CSFP) increase.

Which of the following is false regarding inhalation agents A. It should not be metabolized in the body, should exert no systemic toxicity, and should not provoke allergic reactions. B. It should produce maximum and predictable depression of the cardiovascular and respiratory systems and should not interact with other drugs used commonly during anesthesia (e.g. vasopressor agents or catecholamines). C. It should be completely inert and completely eliminated and rapidly in the unchanged form via the lungs. D. It should be easy to administer using special vaporizers. E. It should have a reasonable cost. F. It should not be epileptogenic or raise intracranial pressure.

B. D 12 Commandments of Anesthetic Agents - 7) It should not be metabolized in the body, should exert no systemic toxicity, and should not provoke allergic reactions. 8) It should produce minimal and predictable depression of the cardiovascular and respiratory systems and should not interact with other drugs used commonly during anesthesia (e.g. vasopressor agents or catecholamines). 9) It should be completely inert and completely eliminated and rapidly in the unchanged form via the lungs. 10) It should be easy to administer using standard vaporizers. 11) It should have a reasonable cost. 12) It should not be epileptogenic or raise intracranial pressure.

The drug of choice for MH A. Succinylcholine B. Dantrolene C. Insulin D. Nitroglycerin

B. Dantrolene - Management of MH Crisis (adapted from www.mhaus.org) Call for help. Stop Volatile anesthetics. Initiate MH Protocol and call 800-644-9737 and place on speakerphone. Prepare patient for central line, a line, place large bore IV 14/16g. Administer Dantrolene starting at 2.5mg/kg up to 10mg/kg. Initially dose using actual body weight. 20mg/vial, 60ml of sterile water. Treatment of patient to counteract hyperthermia Gastric and urinary lavage with cold/ice water. Ice packs to patient. Insulin gtt started, hyperventilate, albuterol treatments to decrease arrhythmias. Fluids wide open. Measure coags and electrolytes.

At the cellular level, volatile anesthetics __________ intracellular free calcium (Ca2+) in cardiac and vascular smooth muscle. A. Increase B. Decrease

B. Decrease - At the cellular level, volatile anesthetics reduce intracellular free calcium (Ca2+) in cardiac and vascular smooth muscle. This is believed to be a reduction in Ca2+ influx through the sarcolemma and a depression of depolarized-activated Ca2+ release from the sarcoplasmic reticulum. End result? Depression of the contractility of cardiac muscle along with dilation of peripheral vasculature and results in hypotension. Know your labs prior to entering the OR.

The presence of oxygen ______ the arrhythmogenic effect A. Increases B. Decreases

B. Decreases - Ether molecules also contain Oxygen (O) which also decreases the arrhythmogenic effects.

This anesthetic during light anesthesia maintains CI without and increase in HR, but for deeper levels of anesthesia, CI is supported by an increase in HR. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide

B. Desflurane - Conversely, N2O with opioids augments cardiac depression because N2O also produces a direct negative inotropic effect. Desflurane during light anesthesia maintains CI without and increase in HR, but for deeper levels of anesthesia, CI is supported by an increase in HR. Population to be careful? MI, Aortic Stenosis, CHF, LVF, CAD. In all anesthetics, Desflurane, Isoflurane, Sevoflurane all have a common theme: the longer it is delivered, CI and HR increase slightly. In healthy volunteers who were under anesthesia for 8 hours with either Desflurane/Sevoflurane lead to an increase in pupil size and HR independent of surgery.

This has been shown to resist biodegradation after 7.35 MAC hours. A. Isoflurane B. Desflurane C. Halothane D. Sevoflurane E. Enflurane F. Methoxyflurane

B. Desflurane - Desflurane has been shown to resist biodegradation after 7.35 MAC hours. Measured by the urine excretion of TFA or Trifluoroacetic Acid and is a marker specific to Desflurane metabolism.

This is highly irritating to the lungs. A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

B. Desflurane - Desflurane is highly irritating to the lungs. It is not ideal for mask inductions for concentrations greater than 6% and the reason why it is not used in the pediatric and adult populations. Though a known irritant, Desflurane can be used in patients with reactive airways for anesthetic maintenance. All volatile anesthetics relax airway smooth muscle and produce bronchodilation by way of inhibiting calcium influx. They have also been used to treat refractory status asthmaticus.

Advantages of this inhalation anesthetic include: rapid uptake and elimination, stable molecular structure, and no significant systemic toxicity. Disadvantages include: airway irritant, expensive, needs special electrically-heated vaporizers, rapid increases can lead to reflex tacycardia and hypertension, trigger for malignant hyperthermia A. Isoflurane B. Desflurane C. Sevoflurane D. Nitrous Oxide

B. Desflurane Advantages Rapid uptake and elimination Stable molecular structure, Minimal biotransformation No significant systemic toxicity Possible neuro- and cardiac protection Disadvantages Airway irritant Expensive compared to the other agents Needs special electrically-heated vaporizer Rapid increases in inspired concentration can lead to reflex tachycardia and hypertension Trigger for malignant hyperthermia

Results from the dilution of alveolar oxygen concentration by the large amount of nitrous oxide A. Absorption atelectasis B. Diffusion hypoxia C. Pulmonary shunt D. Alveolar dead space

B. Diffusion hypoxia Diffusion Hypoxia! Results from the dilution of alveolar oxygen concentration by the large amount of nitrous oxide leaving the pulmonary capillary blood at the conclusion of nitrous oxide elimination. Can be prevented by filling the patient's lungs with oxygen at the conclusion of nitrous administration.

The more soluble the drug (high blood/gas coefficient), the slower the brain and spinal cord uptake and therefore the ___________ the anesthesia achieved by the patient. A. Faster B. Slower

B. Slower - The Blood/Gas solubility (partition) coefficient is an indicator of the speed of onset/uptake and elimination. It reflects the proportion of the anesthetic that will be soluble in blood, bind to blood components, and not readily enter the tissues (blood phase) versus the fraction of the drug that will leave the blood and quickly diffuse into tissues (gas phase) The more soluble the drug (high blood/gas coefficient), the slower the brain and spinal cord uptake and therefore the slower the anesthesia achieved by the patient. Soluble drugs stay in the blood longer, in greater proportion than less soluble agents and thus less drug is released to the tissues during the early rapid uptake phase of induction. The blood has a greater affinity for the agent and is released from the blood with more difficulty...

This happens when decreases in CMRO2 are accompanied by increases in CBF A. Overpressuring B. Uncoupling C. Underpressuring D. Coupling

B. Uncoupling - Uncoupling Occurs when a decrease in CMRO2 is accompanied by increases in CBF. Inhalation agents produce this effect. N2O causes an increase in CBF and may be related to a sympathoadrenal-stimulating effect. N2O coupled with a volatile anesthetic causes a reverse effect where CMRO2 is increased.

A Boston dentist on October 16, 1846 "conclusively" demonstrated the use for ether in surgical anesthesia in the "Ether Dome" or modern day Operating Room at Massachusetts General. A. Humphrey Davis B. William Morton C. Crawford Long D. Charles Jackson E. Edmund Andrews

B. William Morton - William T.G. Morton, a Boston dentist on October 16, 1846 "conclusively" demonstrated the use for ether in surgical anesthesia in the "Ether Dome" or modern day Operating Room at Massachusetts General. John Collins, a visiting surgeon exclaims "This is no humbug!" "I have seen something today that will go around the world!"

Which of the following is false regarding inhalation agents A. It should have a pleasant odor, be nonirritating the the respiratory tract, and result in pleasant and rapid induction of anesthesia. B. It should possess a high blood/gas solubility, which permits rapid induction of and rapid recovery from anesthesia. C. It should be chemically stable in storage and should not interact with the material of the anesthetic machine and circuits or with soda lime. D. It should be neither flammable nor explosive. E. It should be capable of producing unconsciousness with analgesia and preferably, some degree of muscle relaxation. F. It should be sufficiently potent to allow the use of low inspired-oxygen concentration when necessary.

B., F 12 Commandments of Anesthetic Agents - 1) It should have a pleasant odor, be nonirritating the the respiratory tract, and result in pleasant and rapid induction of anesthesia. 2) It should possess a low blood/gas solubility, which permits rapid induction of and rapid recovery from anesthesia. 3) It should be chemically stable in storage and should not interact with the material of the anesthetic machine and circuits or with soda lime. 4) It should be neither flammable nor explosive. 5) It should be capable of producing unconsciousness with analgesia and preferably, some degree of muscle relaxation. 6) It should be sufficiently potent to allow the use of high inspired-oxygen concentration when necessary.

All inhalational anesthetics except this Desflurane have the ability to produce bradycardia and disruption of AV nodal conduction excluding 2nd and 3rd degree heart block A. Sevoflurane B. Desflurane C. Isoflurane D. Nitrous Oxide E. Halothane

C. Isoflurane - All inhalational anesthetics except Isoflurane and mostly likely Desflurane have the ability to produce bradycardia and disruption of AV nodal conduction excluding 2nd and 3rd degree heart block. Anesthetics depress slow response action potentials. Examples: SA, AV Nodal Tissue. Fast response Action Potentials: Atrial and Ventricular musculature and Purkinje Fibers. When fibers become ischemic, volatile anesthetics are prone to produce reentrant excitation. Reentry occurs when a propagating impulse fails to die out after normal activation of the heart and persists to re-excite the heart after the refractory period has ended, is the electrophysiologic mechanism responsible for the majority of clinically important arrhythmias. Included among these arrhythmias are atrial fibrillation, atrial flutter, atrioventricular (AV) nodal reentry, AV reentry involving a bypass tract, ventricular tachycardia after myocardial infarction (MI) with the presence of left ventricular scar, and ventricular fibrillation. Volatile Anesthetics have the ability to decrease the amount of catecholamines necessary to evoke dysrhythmias.

This represents the MAC necessary to block the adrenergic response A. MAC B. MAC-awake C. MAC-BAR

C. MAC-BAR - MAC BAR 95 Blocks Adrenergic Response to skin incision. These are changes in plasma concentration of norepinephrine, heart rate, rate pressure product and mean arterial pressure. Patient will show no signs of reactivity to pain of surgical stimulation. Requires a greater depth of anesthesia than preventing skeletal muscle movement. Generally 1.2-1.3 times MAC or also 20%-30% over MAC.

Which volatile anesthetic is noted to reduce the cerebrovascular tone significantly A. Desflurane B. Isoflurane C. Nitrous Oxide D. Sevoflurane

C. Nitrous Oxide - N2O causes an increase in CBF and may be related to a sympathoadrenal-stimulating effect. N2O coupled with a volatile anesthetic causes a reverse effect where CMRO2 is increased.

Which of the following is an inorganic molecule A. Sevoflurane B. Halothane C. Nitrous Oxide D. Desflurane

C. Nitrous Oxide - The action of an anesthetic in the body is a result of the drug's chemical structure and its interaction with the cellular receptor complex. There are two types of Inhalational Anesthetics: Inorganic molecules- Nitrous Oxide N2O Halogenated Ethers- Isoflurane/Sevoflurane/Desflurane. They bind to the CNS and spinal cord membranes to produce reversible depression. There is no single identifiable "anesthetic receptor" but postulated that there are multiple sites of action. What we do know is that once a "critical concentration" of drug has entered the brain and spinal cord, loss of consciousness is achieved.

Which of the following is an indicator of potency in inhalation anesthetics A. Blood/gass partition coefficient B. Minimum alveolar concentration C. Oil/gas solubility D. Concentration

C. Oil/gas solubility - Oil/Gas Solubility It is an indicator of potency. The higher the coefficient, the more potent the drug. This means that because an anesthetic must cross over the blood brain barrier, and penetrate the lipid cell membrane to produce action. Highly lipid soluble agents access the brain and spinal cord easier.

Advantages of this inhalation anesthetic includeL rapid uptake and elimination, nonpungent, possible neuro and cardio protection. Disdvantages include: reacts with soda lime and can be a triger for MH, and some biotransformation A. Isoflurane B. Desflurane C. Sevoflurane D. Nitrous Oxide

C. Sevoflurane Advantages Rapid uptake and elimination Nonpungent Excellent for inhalation induction Cardiovascular effects broadly comparable to those of isoflurane Possible neuro- and cardiac protection Disadvantages Reacts with soda lime Trigger for malignant hyperthermia Some biotransformation

The most sensitive evoked potential A. Auditory B. Brainstem C. Visual D. Sensory

C. Visual - Visual evoked potentials are the most sensitive while brainstem evoked potentials are most resistant.

Which of the following factors does not reduce MAC A. Opioids B. Anemia C. Young age D. Sedative hypnotics

C. Young age - Factors That Reduce MAC • Increased age • Hypothermia • Administration of sedative hypnotics • Coadministration of other anesthetics • α2-Agonists • Opioids • Acute ethanol consumption • Hypoxemia • Hyponatremia • Anemia (less than 4.3 mL O2/dL blood) • Hypotension (MAP less than 50 mm Hg) • Pregnancy • Lithium