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51 Cards in this Set
- Front
- Back
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What are the factors of an ideal Anesthetic?
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Induce rapidly
Wide safety margin Rapid recovery No adverse effects |
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What is the thought behind balanced anesthesia?
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No one agent can provide the ideal factors to provide a state of anesthesia, so multiple drugs are used in to meet the needs of certain procedures.
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What is the first stage of Anesthesia?
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Analgesia:
early - analgesia w/out amnesia late - analgesia+amnesia+euphoria |
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What is the second stage of Anesthesia?
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Excitement/Delirium
"Limit this stage" Irregular Resp. Nausea/Vomiting Incontinence |
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What is the third stage of Anesthesia?
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Surgical
Unconscious Regular Resp. Decrease eye movements |
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What is the fourth stage of Anesthesia?
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Medullary Depression
Resp. Arrest Cardiac Arrest No eye movement |
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What determines the depth of the anesthesia?
What is this path? |
Amount of Anesthesia in the CNS
Lung/Alveoli - Blood/Artery - Brain/Neurons |
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What does MAC stand for?
What is MAC? |
Median Alveolar Concentration
Inhaled anesthetic - produces immobility in 50% of patients subjected to a noxious stimulus (surgical incision) |
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What correlates with increased potency of gases at steady states?
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Lipids
Increased Potency = Increased Solubility in oil (lambda Oil/gas) lambda oil/gas Increases, then MAC decreases |
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Which inhaled anesthetic has the greatest MAC and the lowest lambda oil/gas?
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Nitrous Oxide
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[Individual gas] in a mixture of gases is proportional to its _____
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partial pressure
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The transfer of Anesthetic is limited by what?
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Perfusion rather than Diffusion
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What are the three main points to the transfer of anesthetics in perfusion?
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1. Obeys law of mass action (diffusing across lung epithelium)
2. Moves down pressure gradient 3. Gas must be dissolved in blood to perfuse tissues |
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What inhaled anesthetics have low solubility in the blood?
What does this mean? |
Desflurane and NO
Equilibrium - pulmonary blood and alveolar air reached in small amt. |
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What inhaled anesthetics have intermediate solubility in the blood?
What does this mean? |
Sevoflurane and Isoflurane
Takes a larger amt. |
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What inhaled anesthetic has high solubility in the blood?
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Halothane
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What are the steps to determining the Alveolar partial pressure of an inhaled anesthetic?
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#1 >/ Ventilation = >/ delivery of anesthetic leading to >/ inspired anesthetic = >/ P(alv)
#2 >/ P(alv) = >/ uptake into the blood = >/ cardiac input #3 /> P(alv) |
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What enables a faster induction of Inhaled anesthesia?
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Lower blood Solubility
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The oil/gas partition coefficient predicts _____
The blood/gas partition coefficient predicts the _____ |
potency
rate of induction |
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What are the effects that hyper and hypo ventilation have on the inhaled anesthetics?
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Hyper increases effects of more soluble Inhalants (Halothane)
Hypo slows induction of anesthesia |
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What are the effects of cardiac output on induction?
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Increased CO slows induction esp. with soluble gases
Decreased CO speeds induction because P(alv) equilibrates quickly |
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What are the variables of elimination/ recovery?
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Similar to Induction
Redistribution to the lungs >/ elimination Metabolism >/ elimination |
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What are the factors that can influence the depth of anesthesia?
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1) Genetics - (Halothane)
2) Pregnancy - Extra Compartment 3) Stress/Anxiety - >/ HR think pre-medicate w/ Benzodiazepines 4) Metabolic rate/Age |
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MAC values are /> in the _____
MAC values are >/ in _____ MAC values in _____ pt > _____ pt |
elderly
infants healthy, debilitated |
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MAC values are /> in pt who’ve received ....
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CNS depressants or other anesthetic gases or adjuncts (e.g. Nitrous oxide)
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MAC values are >/ in pt who’ve acquired a tolerance to the .....
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CNS-depressant effects of other agents (alcohol, barbiturates, benzodiazepines)
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What are MAC values NOT affected by?
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Sex
Height Weight |
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What are the two common MOA of Inhaled Anesthetics?
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GABA(a) - glycine receptor-chloride channel
(synaptic inhibition by binding to specific sites on subunits) Nicotinic ACh - 5HT3- NMDA glutamate receptor activity |
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What are the CNS effects of Inhaled Anesthetics?
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>/ threshold
/> neuronal activity >/ hyperpolarization /> metabolic rate of brain >/ cerebral blood flow by /> cerebral vascular resistance (N2O does this the least) |
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What are the respiratory effects of Inhaled anesthetics?
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All Inhaled Anesthetics are Respiratory Depressants
/> Vent. response to CO2 >/ Resp. rate /> Tidal Volume /> Mucociliary function (infection in airway) |
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How does inhaled anesthetics effect the Cardiovascular System?
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- Dose-related depression of contractility
- Can cause coronary vasodilation and Coronary Steal |
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What the Heck is Coronary Steal?
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Vasodilation in healthy heart tissues steals blood away from atherosclerotic arteries in patients with ischemic heart disease
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What is a rare adverse effect of general anesthesia involving some volatile anesthetics and _____?
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Malignant Hyperthermia
succinycholine |
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What occurs in the acute Malignant Hyperthermia?
What progresses from here? |
- Masseter or generalized muscle rigidity
>/ oxygen use and C02 production tachycardia - Body temp climbs very high and can be fatal |
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What is the treatment of Malignant Hyperthermia?
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Stop admin of agents
Admin 100% O2 IV Admin of Dantrolene |
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What does Dantrolene do to aid in the treatment of Malignant Hyperthermia?
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Inhibits calcium transport thus decreasing calcium in the muscle and hypermetabolism in the muscle which is responsible for the increased temp.
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What are the Pros and Cons for NO2?
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- Incomplete anesthesia, but sedation
- No muscle relaxation - Less effect on ventilatory response to CO2 than others - Good analgesic - Advantages when combined w/other gases |
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What are the advantages of using NO2 combined with other gases?
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Reduce [gas]
Increase safety Decrease side effects |
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What are the Pros and Cons of using Isoflurane?
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- Most widely used volatile anesthetic
- Pungent odor; not used for induction - Tendency to irritate airway and cause the patient to cough, hold their breath or have a laryngospasm |
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What are the Pros and Cons of using Desflurane?
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- Rapid induction/ fast recovery
- Airway irritation (isoflurane) - Maintains anesthesia and allows rapid change - Low hepatotoxicity |
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What inhaled Anesthetic is contraindicated in patients susceptible to malignant hyperthermia?
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Desflurane
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What are the Pros and Cons of using Sevoflurane?
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- Pleasant odor
- Lack of airway irritation - Rapid onset of action – induction for kids/ good recovery - Metabolized by liver, 2-3% biotransformed - Not hepatoxic |
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What Anesthetic Adjuncts are commonly used for sedation?
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Benzodiazepines:
- Midazolam (Versed) - Lorazepam (Ativan) |
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What is the antidote for a benzodiazepine overdose?
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Flumazenil
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Why are Opiod analgesics used as adjuvants to anesthetics?
What are they? |
- Used to induce anesthesia and pre-empt pain sensation
- Fentanyl, Alfentanil, sufentanil (induction and analgesia) - Morphine (analgesia) |
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What is the antidote for an Opioid Overdose?
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Naloxone (Narcan)
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What has rapid induction of anesthesia, short duration of action and rapid clearance?
It is metabolized to inactive compound by liver enzymes |
Propofol
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What are the cardiovascular effects of Propofol?
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Can depress BP w/out reflex tachycardia
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What are the respiratory effects of Propofol?
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Apnea
Decreased response to CO2 Safe for asthmatics |
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What are the Advantages of Propofol?
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- Rapid recovery from anesthesia
- Less nausea and vomiting |
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What are the Cautions when using Propofol?
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- Doses reduced;elderly, debilitated, used w/ CNS depress drugs
- No analgesic properties - Pain on injection |
