Chapter 11 General and Local Anesthetics Flashcards
anesthesia
state of reduced neurological function
general anesthesia
-involves complete loss of consciousness and loss of body reflexes, including the respiratory muscles
-allows for surgical procedures under controlled conditions by anesthesia providers
-inhalation and parenteral
adjunct general anesthetic
enhances therapy when used with other drugs
general anesthetic mechanism of action
-each has a different chemical makeup and potency
-related to fat solubility in drugs, makes it easier to cross the blood brain barrier
-progressive reduction of sensory and motor CNS function
-lose senses, then consciousness
-cardiac and respiratory are last to be interrupted
general anesthetic indications
Unconsciousness, relaxation of skeletal and smooth muscles
general anesthetic contraindications
known allergy, pregnancy, narrow angle glaucoma, malignant hyperthermia (genetic metabolic reaction to general anesthesia)
general anesthetic adverse effects
dose dependent, can negatively affect cardiac, renal, respiratory, and neurological functions
malignant hyperthermia
-genetic metabolic reaction to general anesthesia
-S/S- rapid increase in body temp, tachycardia, tachypnea, muscular rigidity
-High Risk- children, adolescents, muscular/skeletal abnormalities
treatment for malignant hyperthermia
Dantrolene and supportive care
general anesthesia drug examples
-Dexmedetomidine (Precedex) - can cause hypotension
-Ketamine- hallucinations, can bump up BP
-Nitrous Oxide - laughing gas, weak, dental
-Propofol- used for intubated patients, could decrease BP
-Sevoflurane - quick to sleep, quick to wake up
moderate sedation drugs
-does not cause complete loss of consciousness or respiratory distress
- Midazolam with Fentanyl or Morphine, Propofol, Ketamine
local anesthesia
-does not involve paralysis of respiratory function, elimination of pain sensation in the tissues innervated by the anesthetic agent
-reduce pain sensation at peripheral nerve level
local anesthesia routes
-Parenteral- injectable or spinal injection
-Topical- directly on skin and mucous membranes
-Central- spinal, intrathecal, epidural
-Peripheral- infiltration, nerve block
local anesthesia mechanism of action
interfere with nerve transmission at local site, block generation and conduction of impulses through nerve fibers
local anesthesia indications
surgical, dental, diagnostic procedures, childbirth
local anesthesia contraindications
known allergy
local anesthesia adverse effects
-limited mostly related to increased plasma concentrations of drug
-spinal headaches - blood patch to treat
-allergic reactions are rare
types of local anesthetics
-Ester Type
-Amide Type (amides have an “I” before “cain, Esters do not)
Ester Type examples
Benzocaine, Procaine, Tetracaine
Amide Type examples
Bupivacaine, Lidocaine, Prilocaine
Lidocaine (amide)
-most common local anesthetic
-often combined with epinephrine
-infiltration, nerve block
-Topical- EMLA cream
-IV-not local, used for non opioid pain management
Neuromuscular Blocking Drugs (NMBDs)
-prevents nerve transmission in skeletal and smooth muscles, leading to muscle paralysis-including respiratory muscles
-causes paralysis, not sedation or loss of consciousness
-DO NOT give these with paralytics
NMBDs mechanism of action
depolarizing and non depolarizing
-Depolarizing: bind in place of Ach to cholinergic receptors at endplates of neuromuscular junctions and mimic action of Ach- agonists
-Phase 1: depolarizing phase- muscles twitch
-Phase 2: muscle becomes paralyzed
-Non depolarizing: binds to Ach receptors at neuromuscular junction but block the action of Ach-antagonist
NMBD effects
muscle weakness or total flaccid paralysis
NMBD indications
maintaining skeletal paralysis during surgery or to facilitate intubation
NMBD contraindications
known allergy, history of malignant hyperthermia, penetrating eye injuries, narrow angle glaucoma, burns, crash injuries
NMBD adverse effects
muscle spasms, hyperkalemia, bronchospasms, hypotension, excessive bronchial and salivary secretion, increased intraocular pressure, increased intracranial pressure
NMBD toxicity
-can cause prolonged paralysis which means prolonged ventilation
-cardiac collapse die to histamine release
Anti cholinesterase Drugs
displace non depolarizing NMBD molecule and return it to original state
NMBD examples
-Succinylcholine
-Rocuronium
-Vecuronium
