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43 Cards in this Set
- Front
- Back
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what are the three phases of general anesthesia?
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-induction
-maintenance -emergence |
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what are the four stages of induction?
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-analgesia
-excitement -surgical anesthesia -medullary depression: cardiorespiratory collapse |
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what are the signs that surgical anesthesia is not present?
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-intact eyelid reflex
-pt is swallowing -respiration is irregular in rate and depth |
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what signs appear as anesthesia deepens?
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-progressive reduction in tidal volume
-diaphragmatic breathing is very prominent -arterial BP decreases |
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__________ roughly indicates anesthetic dosage
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hypotension
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minimum alveolar concentration (MAC)
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-represents one point on the dose-response curve (ED50)
--concentration(partial pressure) that results in immobility in 50% of pts when exposed to a noxious stimulus (surgical incision) |
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MAC for nitrous oxide
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-105% ::pure N2O(100% partial pressure) is not even equal to 1 MAC
-least potent of the inhaled anesthetics |
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ED100 at about ______; usually _________is necessary for surgery when an inhalation agent used alone
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(1) 1.3 MAC
(2) 1.5-2.5x the MAC |
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clinical uses of nitrous oxide
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-analgesia (only to stage 2 and no muscle relaxation)
-adjuvant to supplement actions of other inhaled anesthetics -rapid induction |
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characteristics of halothane
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-rapid induction and emergence
-greater accumulation than with other agents -slower clearance; grogginess for several hours |
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halothane effects on CV system
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-sensitizes myocardium to effects of circulating catecholamines
-arrythmogenic action |
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halothane effects on respiratory system
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-alveolar hypoventilation and arterial hypercapnia
-blunts/abolishes respiratory drive in response to/protection against hypercapnia and hypoxemia |
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halothane causes idiosyncratic______
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hepatotoxicity (acute postoperative hepatitis)
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what are the circulatory actions of isoflurane?
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-dose-dependent decrease in arterial BP due to peripheral vasodilation and TPR
-CO maintained(peripheral vasodilation results in reflex tachycardia) |
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In what way does isoflurane have a lesser tendency to cause arrythmias?
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-it does not sensitize the myocardium to exogenously administered EPI
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what are the respiratory actions of isoflurane?
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-it impairs ventilatory drive in response to hypoxemia and hypercapnia
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why was methoxyflurane withdrawn from the market?
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-potential for serious renal toxicity
-metabolized by P450 isoenzymes in kidney and liver -releases inorganic fluoride -peak plasma fluoride levels correlated with incidence and severity of postoperative renal dysfx |
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what are the problems with desflurane?
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-not suitable for induction
-high incidence or respiratory irritation -coughing, breath-holding,apnea,increased secretions,laryngospasm |
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seroflurane causes the lowest amount of___________
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airway irritation
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major use for seroflurane
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maintenance
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uses of midazolam (Versed)
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-preoperative medication
-IV conscious sedation -suppress seizure activity |
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what are the clinical uses of opioids in anesthesia?
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-preoperative analgesia
-use of lg doses to acheive general anesthesia in pts undergoing cardiac or other major surgery where circulatory reserve is minimal |
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when using _______, post-op respiratory depression may occur and may require assisted ventilation and use of naloxone
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fentanyl
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what produces a state of "neuroleptic analgesia"?
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droperidol/fentanyl
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state where pt is psychologically indifferent to the environment and free from pain, but may still be conscious
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"neuroleptic analgesia"
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ADR of etomidate
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-high incidence of N/V, pain on injection, and myoclonus
-may also cause adrenocortical suppression for up to 8hrs by inhibitory effects on steroid synthesis |
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what produces a state of "dissociative amnesia"
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-ketamine
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-catatonia (sedation, immobility, eyes open with slow nystagmic gaze), amnesia, and analgesia
-pt feels dissociated and different from the environment |
"dissociative amnesia"
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CV effects of ketamine
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-CV stimulation is marked and results in increased BP and HR
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recovery from ketamine?
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-slow and often marked by disorientation, disturbing dreams, hallucinations, and sensory/perceptual illusions (emergence "delirium" rxns)
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how is propofol formulated?
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-an egg-lecithin (oil-in-water) emulsion for IV admin
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effectiveness of propofol
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-very rapid induction
-more rapid and complete recovery than any other IV inducing agent |
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CV effects of propofol
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-lg doses markedly depress arterial BP by lowering TPR (peripheral vasodilation) and negative inotropic effects
-generally, CV depression is more profound than seen with thiopental due to blunted baroreceptor response - |
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respiratory effects of propofol
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-dose-dependent respiratory depression
-significantly decreases the ventilatory response to hypoxia and hypercapnia |
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___________ does not trigger malignant hyperthermia and may be DOC for induction in susceptible pts
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propofol
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what are the indications for use of dexmedetomidine?
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-for use in the ICU to sedate pts who are initially intubated and mechanically ventilated
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__________ is the DOC as an IV anesthetic for outpatients undergoing ambulatory surgery
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propofol
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why is prorofol the DOC for outpatients undergoing ambulatory surgery?
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-rapid loss of consciousness
-rapid recovery with less residual sedation and fatigue |
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clinical use midazolam as IV anesthetic?
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-faster onset and may be used for induction in some cases, but its slow elimination usually causes excessively slow recovery and longer cognitive impairment than other agents
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_____________ can be used optimally to produce conscious sedation, anxiolysis, and amnesia, without causing respiratory depression, nausea, and vomiting
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sedative-hypnotics
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most widely used sedative hypnotic for conscious sedation
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midazolam
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dosing cautions with midazolam
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-steep dose-response curve so that careful titration is necessary to avoid oversedation or respiratory depression
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recovery time for midazolam fast or slow?
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slow
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