Anesthetics-General Flashcards
describe the anesthetic ether
relatively safe for user
pungent odour
highly explosive
describe the anesthetic chloroform
relatively dangerous *severe CVD, hepatoxic
non-pungent odour
non-explosive
describe the anesthetic Nitrous oxide
only partial anesthesia, but excellent analgesia
used in dental clinics, and sometimes in hospitals
describe the anesthetic cyclopropane
most populat 1929-1960
flammable - O.R. explosions
describe the anesthetic halothane
improvement in safety
revolutionized anesthesia
introduced in 1956
what are the 7 characteristics of the ideal inhalant anesthetic?
chemically stable with out preservatives compatible with machines non-flammable potent produces unconsciousness while maintaining brainstem function non-pungent odour negligible toxicity
what is typically used today (chemical backbone of the anesthetic)?
halogenated hydrocarbons, since halogenated aliphatic hydrocarbons or ethers.
the replace them of H- with halogens reduces flammability and enhances stability; more f- more stable.
what are the 3 most comment selected inhalants that are used today?
halothane, isoflurane and sevoflurane.
what are the 4 requirements for optimal anesthesia?
- unconsciousness
- analgesia
- amnesia
- muscle relaxation
how is the anesthesia administered?
low [ ] inhalant to render patient unconscious, and use low [] of other drugs to inhibit pain or relax the muscles.
- administer sedative or anioxlytic and analgeesic
- induce unconsciousness
- maintain in unconscious state
what is the goal of a premedication?
- sedation
- analgesia (intra/post operative pain relief)
- reduce [] of induction agent and anesthetic required.
what are induction agents? (what do they do/ goal)
product general anesthesia administered IV goal: rapidly render patient unconscious effects wear off rapidly helps speed up stage 2 to 3 in the stages of anesthesia during induction.
what are the 4 stages or planes of anesthesia during induction?
- state of analgesia (semi-consciousness)
- stage of excitement, (struggle, comabitve behaviour)
- stage or plane of surgical anesthesia (unconsious, ceased movement)
- To far process stage of medullary depression–> death
what are premedications?
variety of injectable drugs used to calm patient, reduce amount of general anesthetics needed to inhibit pain intra- and post op
what are the 3 main types of premedications?
- sedatives/ anxiolytics (calm patients)
- hypnotics- to induce sleepiness
- analgesics (minimiza/abolish intra & post op pain)
what is the major class of sedatives used and name two examples.
benzodiazepines (BZDs)
1. diazepam, and lorazepam
why is diazepam a useful pre-med?
aniolytic/sedative effect hypnotic muscle relaxant *trade name is valium it facilitates the binding of GABA to its receptor
what is a GABAa R?
its a hetero-pentameric lignand-gated chloride channel; when binded to GABA, the alpha unit opens the channel and hyper-polarized the cell, which inhibits the excitation/ AP. the overall effect depends on location of receptors and the regions of the brain that are inhibited.
what are the most common GABAa R subunits?
there are 21, the most common are 2alpha 1, 2beta2, and 1gama 2.
what are endozepines?
they are endogenous, meaning they bind to the same site s benzodiazapines.
what are BZDs a good pre-medication?
relatively safe -> need GABA to be present
BZD have little effect on CV system
Dose-dependent respiratory depression, but little effect at therapeutic dosages
hepatic metabolism.
what are the most common adverse effects of BZDs?
drowsiness and confusion
what are some adverse effects/ overdose?
do not combine with alcohol, can be fatal via CNS depression. overdose however can be reversed by the GABA R antagonist Flumazenil
what makes diazepam useful as a premed?
administered prior to anesthesia -> less anesthetic required to produce “surgical plane”.
Also relaxes skeletal muscles.
