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41 Cards in this Set
- Front
- Back
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What is the driving force of Inhalation anesthetics?
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partial pressure differences
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What stage of anesthesia starts w/ the patient conscious and ends w/ LOC?
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stage 1: induction
first analgesia w/o amnesia, then amenesia |
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What stage of anesthesia is the pt in if there are delirious vocalizations and irregular rate and volume?
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Stage 2: Excitable stage
* it is desirable to pass through this stage as quickly as possible |
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Do low or high solubility anesthetics have faster onset and recovery?
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low solubility
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What are the first tissues to come to equilibrium in the body?
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those w/ HIGH blood flow and LOW capacity (brain, heart, kidney, endocrine organs)
then those w/ lower blood flow but larger volumes (skin and muscle) finally, those w/ low blood flow and large capacity (mainly fat) |
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The LARGER the concentration anesthetic gradient between the arterial and venous blood supply, the ______________ the onset of anesthesia
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The LARGER the concentration anesthetic gradient between the arterial and venous blood supply, the LONGER the onset of anesthesia
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What is the major factor determining rate of elimination of anesthetics?
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the blood:gas coeffecient (the lower the coeffecient the faster the anesthetic moves from teh blood to the gas in the alveoli and the faster the recovery)
Other factors include tissue solubility, pulmonary blood flow and ventilation rate |
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What is diffusion hypoxia?
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when an aneshetic w/ low solubility in blood, such as nitrous oxide, causes rapid diffusion of the anesthetic from teh blood into the alvelous and diluting the oxygen in the alveolus
*you can prevent this by putting the patient on 100% oxygen* |
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What is potency defined as?
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the minimal alveolar concentration to prevent movement to a standarized stimulus in 50% of the population. This value, the MAC, is equivalent to the ED50 and is roughly additive.
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What is the major MOA for inhaled anesthetics?
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they enhance the action of GABA at the GABAa receptors: they increase the GABA-induced Cl-flux leading to an enhanced inhibition of neuronal activity
generally, most affect ligand-gated ion channels |
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Can N2O be given alone to acheive surgical anesthesia?
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NO, its an excellent analgesic but a very weak anesthetic.
--> administered in combo w/ other anesthetics it has very RAPID onset/recovery |
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N2O side effect: (increases or decreases)
1. Arterial pressure, heart rate, cardiac output 2. Respiratory rate 3. Tidal volume 4. Cerebral blood flow 5. Skeletal muscle relaxation |
1. Little effect on BP, HR, CO
2. Increases RR 3. Decreased TV 4. Increases CBF 5. Does not cause muscle relaxation |
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Why is Isoflurane administered AFTER induction w/ IV anesthetic and used as a maintenance anesthetic?
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because the pungent odor causes coughing and laryngospasm
Desflurane also irritates the airways and causes coughing, salivation, breath holding and broncospasm, so it is also used as a maintenance drug |
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Which anesthetic has a low blood:gas partition coeffecient, is not soluble in fat, and therefore causes RAPID induction of anesthesia and allows for RAPID changes in depth of anesthesia w/ RAPID recovery?
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desflurane
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What hydrocarbon has rapid, smooth induction of anesthesia w/ rapid recovery from anesthesia, is not pungent and often used in outpatient surgery?
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sevoflurane
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In which hydrocarbon is cardiac output not maintained as well as the others?
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sevoflurane
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Which hydrocarbon produces enough muscle relaxation to allow intubation in children?
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sevoflurane
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Which hydrocarbon reacts to form Compound A that is nephrotoxic and might limit its use as well as issues w/ industrial process?
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sevoflurane
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Which inhaled anesthetic has a high blood:gas partition coeffecient, soluble in fat, not pungent and is the oldest "modern" anesthetic?
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Halothane
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45% of what inhaled anesthetic is metabolized in the liver to produce trifluroacetic acid?
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Halothane
Trifluroacetic acid can cause an immune reaction: Halothane hepatitis, esp. in those w/ previous exposure |
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What is Malignant hypothermia, and what inhaled anesthetics were noted to cause it?
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severe contractions of skeletal muscle, a massive increase in metabolic rate and hyperthemia, tachycardia, hyperkalemia, and acidosis
Caused by mutation in ryanodine RyR1 receptor Treat w/ dantrolene (inhibits the RYR1 receptor) **Halothane, Isoflurane, Sevoflurane** |
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How is N20 metabolized?
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it is not
exhaled unchanged |
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All inhaled anesthetics increase or decrease ICP?
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increase ICP via increase cerebral blood flow
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What GI affects form N20?
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nausea and vomiting via irritation of chemoreceptors
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What is the effect of desflurane on blood prussure and CO?
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decreases blood pressure due to vascular resistance
CO is maintained |
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Which IV anesthetics is used for hypotension and MI?
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Etomidate
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Which IV anesthetic is used in children undergoing short, painful procedures?
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Ketamine
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What is the MOA of sodium thiopental (and all other barbituates)?
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potentiates GABA-induced Cl- flux at GABAa receptors
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What are the effects of thiopental on CV and Cerebral blood flow?
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CV: dose-dependent decrease in arterial pressure, stroke volume, and cardiac output. Directly depresses the myocardium and increases venous capacitance w/ little chane in peripheral resistance.
The reduction in BP can be significant especially in pts w/ imparied CV function and disease decreases both cerebral blood flow and cerebral metabolsim and oxygen consumption. Does NOT increase ICP, so preferred for pts. w/ cerebral swelling |
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What is the most commonly used anesthetic in the U.S.?
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Propofol
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Is Propofol used for induction or maintenance?
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both
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What is the MOA of propofol?
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potentiates GABA-induced Cl- flux at GABAa receptor similar to barbituates
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What are the major side effects of Propofol?
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CV: peripheral vasodialation & mild depression of cardiac contractility
Resp: produces greater depression than thiopental **Has antiemetic effects and is preferred for those w/ risk of nausea and vomiting** |
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How does multiple doses of sodium thiopental cause prolonged anesthesia versus a single dose?
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due to saturation of fat stores
ONLY used for induction |
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What are the side effects of Etomidate?
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pain at injection
myoclonic movements and postoperative nausea inhibits steriodogenesis: hypotension and electrolyte imbalance due to adrenocortical suppression in critically ill pts |
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What drug causes dissociative anesthesia?
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Ketamine
characterized by catatonia, amnesia and analgesia Patients can moan, have spontaneous limb movements, increased muscle tone, nystagmus w/ papillary dilation, salivation and lacrimation |
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What is the MOA of ketamine
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Ketamine is a congener of phencyclidine and inhibits the glutamate NMDA receptor
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What are the major side effects of ketamine
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CV: stimulates CV system, increase BP, HR & CO
CNS: Increase cerebral blood flow and ICP, but does not decrease cerebral oxygen consumption Delerium, hallucinations and vivid dreams can occur during emergence from anesthesia and for several weeks after anesthesia |
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What 2 anesthetics are also analgesics?
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N20 and ketamine
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What commonly used Benzodiazepine produces sedation, anxiolysis and amnesia?
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Midazolam
*produces minimal venous irritation** |
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What alpha-2-adrenergic agonist is a commonly used adjunct has both sedative and analgesic properties w/ minimal respiratory depression?
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Dexmedetomidine
Side effects: hypotension and bradycardia |
