Term
| What is MAC-Minimum Alveolar Concentration |
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Definition
The concentration of anesthetic that prevents movement in response to
stimulation in 50% of patients.
Determines potency of inhaled anesthetics (1.2-1.3 is typicals during surgery) |
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Term
| Describe each stage of anesthesia and the state of the pt in each stage. |
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Definition
Stage I-Analgesia
Stage II-excitement (seizure potential)
Stage III- surgical anesthesia
Stage IV- medullary paralysis |
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Term
| What are some general principals of inhaled anesthetics |
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Definition
Mainstay of anesthesia
primarily during maintenance phase
depth of anesthesia can be rapidly changed
Fairly easily eliminated |
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Term
| What determines anesthetic uptake? |
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Definition
| Low solubility is preferred. The lower the blood gas partition coefficient the less soluble the drug, the less of it will stay in blood. This leads to rapid induction and recovery. |
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Term
| What are some Pharmacodynamics of Inhaled Anesthetics |
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Definition
Decrease cerebrovascular resistance
Bronchodilation
Decrease minute ventilation
Hypoxic pulmonary vasoconstriction. |
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Term
| Which inhaled anesthetic is well tolerated in children, relaxes skeletal and UTERINE muscle but relatively contraindicated in increased ICP and can cause Hepatic necrosis in older patients. |
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Definition
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Term
Whyewould you not give succinylcholine plus this inhaled anesthetics in burn victims, Duchenne MD, myotonia, osteogenesis imperfecta ?
Which durg is it?
How would you treat the condition. |
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Definition
It would cause malignant hyperthermia
The drug is Halothane
Tx with Dantolene |
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Term
| This drug creates a condition that leads to hypotension, bradycardia, arrhyrhmia and potentiates neuromuscular blocking agents. Name the drug and the condition. |
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Definition
| Halothane hepatitis. Caused by the oxidative metabolism of trifluoroethanol and bromide. Leads to hepatic necrosis. |
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Term
| WHich inhaled anesthetic is widely used for maintenance anesthesia and is the preferred agent for neurosurgical procedures and DOES NOT induce arrythmiAS or sesitize heart to catecholamines like Halothane. |
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Definition
Isoflurane
It is Not tissue toxic |
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Term
| Which inhaled anesthetic is mainly excreted by the kidney and has an adverse effect of CNS excitation and nephrotoxicity |
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Definition
Enflurane
(not recommended in seizure disorder) |
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Term
| This drug has low volatility and rarely tissue toxic. It can cause increased ICP that can be decreased with hyperventilation It is an airway irritant that can cause laryngospasm, coughing and excess secretions |
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Definition
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Term
Rapid induction and recovery makes this drug a good choice in outpt surgeries. Compound A is it's biochemical breakdown and when mixed with soda lime it causes transient renal injury.
This drug can also cause nephrotoxicity. |
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Definition
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Term
| Which drug would you use for induction anesthesia especially with children? |
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Definition
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Term
| What is used in outpatient dental surgery that is more of a potent analgesic than anesthetic and has no metabolism? |
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Definition
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Term
| What happens when 80% of nitrous oxide is used? |
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Definition
| will limit the delivery of oxygen to the blood. |
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Term
| What is the second gas effect and diffusional hypoxia that is caused by nitrous oxide? |
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Definition
Second gas effect- Need to give a lower MAC of inhaled anesthetic when giving it with nitrous oxide. Nitrous oxide is taken up faster from lungs which increases the partial pressure of the alveoli. Due to the remaining second anesthetic your body thinks you were given a higher dose of the second anesthetic.
Diffusional hypoxia- – Upon discontinuation, N2O can displace O2 in the alveoli thus diluting the lungs. The partial pressure btwn the alveoli and the blood vessel may not be enough to sustain life in this pt. Need to treat with 100% oxygen. |
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Term
| What are some other contraindications with Nitrous Oxide? |
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Definition
N2O will exchange with N2; N2O enters the potential space faster than N2 exits because of the blood:gas partition coefficients thus causing an increase in volume and/or pressure. Hence contraindicated in pneumothorax, obstructed middle ear embolli, intaocular air bubble, pulmonary bulla, and intracranial air.
Pulmonary hypertension – N2O increases pulmonary vascular resistance |
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Term
| What is the one reason xenon is not used even though it is extremely insoluble and does not have ANY major adverse effects |
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Definition
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Term
| Which 2 drugs have metabolites that are eliminated by kidney and may potentially cause nephrotoxicity? |
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Definition
| Enflurane and Sevoflurane |
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Term
| Why are intravenous anesthetics used? |
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Definition
rapid induction of anesthesia
recovery is accomplished via redistribution |
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Term
| Which IV anesthetic would you use for rapid induction and is used in patients with head injuries or elevated ICP? |
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Definition
Thiopental and Mehohexital both have rapid induction they are safe in pregnancy
Thiopental decreases cerebral oxygen consumption, cerebral blood flow and intracranial/intraocular pressures, Good for head injury pts and increased ICP |
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Term
Which IV anesthetic causes CNS excitement phenomena
What are the signs and symptoms?
What drug is contraindicated in acute intermittent porphyria? |
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Definition
1) Methohexital causes CNS excitement phenomena
2) s/s are severe hypotension hypovolemic shock, respiratory depression, intraarterial injection, inflammation or necrosis.
Thiopental and Methohexital is contraindicated in acute intermittent porphyria |
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Term
| What is the most common used IV anesthetic in the US and has antiemetic effect? It is the agent of choice in outpt surgery. Also can be used in head injuries and increased ICP. |
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Definition
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Term
| When would you use etomidate (IV anesthetic) what are some adverse effects? |
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Definition
Used for induction in pts with high risk hypotension
Adverse effects are nausea and vomiting, inhibits adrenal cortisol and aldosterone biosynthesis |
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Term
Which IV anesthetic is used in pts at high risk for hypotension and bronchospasm
It is CONTRAINDICATED in elevated ICP and causes CNS emergenece phenomena, indirect sympathomimetic activity. |
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Definition
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Term
| Why are benzos used as an adjunct and how would you treat its toxicity. |
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Definition
For sedation prior to induction or procedures.
Use Flumazenil to treat toxicity |
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Term
What is an anesthetic adjunct that is highly selective agonist of alpha2 AR
receptor
Used short term in intubated and mechanically ventilated ICU pts |
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Definition
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Term
| Which 2 inhaled anesthetics cause increased intracranial pressure that can be reduced by hyperventilation? |
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Definition
| Desflurane and Sevoflurane |
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Term
| What are the therapeutic uses of local anesthetics? |
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Definition
Surgery-skin, subcut. ears, eyes joint, or pelvis.
Labor and Delivery
Diagnostic procedure
management of pain |
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Term
| What are some physiochemical characteristics of local anesthetics? |
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Definition
Weak bases (pKa 8-9)
At physiologic pH, cationic form predominate
Small molecular size → more rapid dissociation from receptor site (shorter duration of action)
Ester links more prone to hydrolysis than amide links
Esters usually have shorter duration of action than amides (t1/2 < 1 minute)
Specific steriochemical configurations associated with different potencies |
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Term
| What kind of receptors do local anesthetics bind to? |
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Definition
They bind intracellular sodium channels. Drug acts on Na channels in an open (inactivated) state to prolong inactivation so conduction of action potential is blocked.
Lengthens refractory period |
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Term
| What kind of periphernal nerves are blocked more easily? |
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Definition
| small diameter, unmyelinated C, lightly myelinated pain fibers, autonomic and sensory fibers are blocked more easily |
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Term
| How would you increase the action of a local anesthetic |
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Definition
| add epinepherine to block peripheral alpha-AR |
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Term
| Why is it important to not inject local anesthetic into the vein? |
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Definition
| local anesthetic can cause systemic toxicity leading to seizures if injected into veins. Can only do this with a turnicate and must remove within short period of time. |
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Term
| Why are hypersensitivity reactions, asthma, dermatitis more common in esters? |
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Definition
| B/c they are hyrolyzed to PABA |
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Term
| What is the concern with using amides in patients with cardiovascular or pulmonary problems? |
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Definition
Amides are metabolized by the liver to methemoglobinemia which tightly binds oxygen leading to a hypoxic state in these pts.
Amides are highly protein bound. (Drug interactions) |
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Term
| Which local anesthetics are esters? |
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Definition
| Cocaine, Procaine, Tetracaine, Benzocaine |
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Term
| Which local anesthetics are amides? |
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Definition
| Lidocaine, Mepivacaine, Bupivacaine, Prilocaine, Ropivacaine |
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Term
| Which local anesthetic has an intrinsic vasocontrictor activity? How does this work? |
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Definition
Cocaine
blocks NE reuptake. High abuse potential.
H |
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Term
| Which local anesthetic is not effective when applied topically so must be injected. Is metabolized to PABA has low potency. May produce loss of consciousness. |
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Definition
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Term
| Which local anesthetic is used for its long duration of action for spinal anesthesia? |
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Definition
| Tetracaine-but may increase systemic toxicity due to slow metabolism |
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Term
| Which local anesthetic can be applied topically and can be bought without a prescription? |
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Definition
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Term
| Why do ppl like Lidocaine? |
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Definition
Faster, more intense, longer suration of action and extensive anesthesia. Found parenteral, Tpical, transdermal.
Can cause loss of consioudness |
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Term
| WHat is special about prilocaine? |
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Definition
| Does not cause vasodilation. But converted to methemoglobinemia. |
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Term
| Which amide is long acting and used for prolonged analgesia in labor and delivery but can cause Cardiotoxicity |
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Definition
Bupivacaine.
low concentration is enough and does not cause cardiotoxicity |
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Term
| What is an intermediate acting amide with similar effects as lidocaine but more toxic to neonates? |
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Definition
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Term
| Which amide is long acting similar to bupivacaine and used for epidural or regional anesthesia? |
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Definition
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