ANESTHESIA Flashcards
TYPES OF ANESTHESIA
o general
o sedation
o regional
GENERAL VS SEDATIVE VS REGIONAL
o GENERAL = suppression of activity in the CNS; unconscious & total lack of sensation
o SEDATION = Inhibition of transmission of nerve impulses between higher & lower centers of the brain; inhibition of anxiety & memory
o REGIONAL = use of local anesthetics to make a portion of the body insensate by blocking transmission of nerve impulses between a part of the body and the spinal cord
⦁ Peripheral = inhibits sensory perception within a specific location (nerve blocks)
⦁ Central = local anesthetic delivered around the spinal cord - removes sensation of the body below the level of the block (spinal & epidural)
ENDPOINTS OF ANESTHESIA
⦁ Hypnosis = temporary loss of consciousness & loss of memory
⦁ Analgesia = lack of sensation; autonomic reflexes are blocked
⦁ Muscle Relaxation
Amnesia (memory loss) = Benzodiazepines
Immobility = Muscle relaxants & Paralytics
Analgesia = Opiates, local anesthetics, Ketamine, NSAIDS
Hypnosis = Barbiturates, Propofol, Etomidate
Anesthesia (inhaled agents) = all of the above!
post op cognitive dysfunction more common with
cardiac surgery & elderly patients
anesthesia risks
⦁ death ⦁ MI ⦁ PE ⦁ Post op N/V ⦁ Post op cognitive dysfunction (persistent confusion lasting weeks or months; more common with cardiac surgery & in the elderly)
the greatest predictor of the probability of a complication occurring
ASA classification
the higher the ASA class =
increased likelihood of surgical or anesthetic complications
the ROOT CAUSE of 11% of adverse anesthetic events =
INCORRECT PRE-OP ASSESSMENTS
ASA CLASSIFICATION
⦁ ASA I = normal healthy patient; no smoking, and none/minimal drinking
⦁ ASA II = pt with mild systemic dz; smoker, or more than minimal drinking, pregnancy, obesity, well controlled DM, well controlled HTN, mild lung dz
⦁ ASA III = pt with severe systemic dz, not incapacitating; DM, poorly controlled HTN, distant hx of MI / CVA / TIA / cardiac stent / COPD / ESRD. Dialysis, active hepatitis, implanted pacemaker, EF < 40%, congenital metabolic abnormalities
⦁ ASA IV = pt with severe systemic dz that is a constant threat to life = recent hx of MI / CVA / TIA / cardiac stent. Ongoing cardiac ischemia or severe valve dysfunction, implanted ICD, EF < 28%
⦁ ASA V = moribund pt who is not expected to survive without the operation; ruptured abdominal or thoracic aneurysm, intracranial bleed with mass effect, ischemic bowel in the face of significant cardiac pathology
⦁ ASA VI = pt is has already been declared brain dead, and whose organs are being removed for transplant
regional / local anesthesia
pain blocked from a part of the body using local anesthetics
types of regional anesthesia
⦁ Infiltrative ⦁ Peripheral nerve block ⦁ IV regional anesthesia ⦁ Central nerve block ⦁ Topical anesthesia ⦁ Tumescent anesthesia
INFILTRATIVE ANESTHESIA (type of regional)
local anesthetic injected in a small area to stop sensation
local anesthetic injected in a small area to stop sensation
infiltrative
PERIPHERAL NERVE BLOCK (Regional type)
local anesthetic injected near a nerve that provides sensation to a portion of the body
local anesthetic injected near a nerve that provides sensation to a portion of the body
peripheral nerve block (regional / local)
IV Regional Anesthesia (Bier Block) (type of regional)
dilute local anesthetic infused to a limb through a vein with a tourniquet placed to prevent the drug from diffusing out of the limb
dilute local anesthetic infused to a limb through a vein with a tourniquet placed to prevent the drug from diffusing out of the limb
IV regional anesthesia (bier block)
dental block or digital nerve block =
peripheral nerve block
Infusion or injection of local anesthetic in or around a portion of the CNS (ex: Spinal - intrathecal, and epidural)
central nerve block
central nerve block
Infusion or injection of local anesthetic in or around a portion of the CNS (ex: Spinal - intrathecal, and epidural)
topical anesthesia
special formulation that diffuses through the skin or mucous membranes (ex: EMLA patches)
tumescent anesthesia
large amount of dilute local anesthesia is infiltrated into the subcutaneous tissue (used in liposuction / various other procedures)
NEUROAXIAL ANESTHESIA INDICATIONS & CONTRAINDICATIONS
= spinal (intrathecal) or epidural
- Indications
⦁ surgery or pain
⦁ appropriate distribution of anesthesia - Contraindications
⦁ Patient refusal
⦁ Infection (near site of injection)
⦁ Coagulopathy (on any blood thinner)
BENEFITS OF SPINAL ANESTHESIA
⦁ decreases surgical time by 12%
⦁ 25% less blood loss
⦁ 50% less intraoperative transfusion requirements
⦁ may decrease the incidence of DVT or PE
decreased surgical time, decreased blood loss, decreased intraoperative infusions, decreased risk of DVT/PE
