General Anesthesia Flashcards
Stages of Anesthesia
Analgesia
Excitement
Surgical Anesthesia
Medullary Paralysis
Inhalation Anesthetics
- Gas NOS - Liquid Halothane Enflurane Isoflurane Desflurane Sevoflurane
IV Anesthetics
Barbs BZDs Propafol Ketamine Etomidate Opioids **BEST RESULT: COMBO OF IV AND INHALED
Partial Pressure Gradient
- Important for speed of induction of inhaled anesthetic
- Blood/Gas Partition coefficient
- More soluble anesthetic is to blood, higher the Partial pressure, slower the onset of action
Minimum alveolar Concentration
- Concentration of Anesthetic which produces immobility in 50% of subjects exposed to a noxious stimulus
- Higher the MAC = Lower Potency = Faster Induction = Faster Recovery
- INC MAC: Hyperthermia, Hypernatremia
- DEC MAC: Hypothermia, Hyponatremia, Hypotension, pregnancy, Drugs (Lithium, Lidocaine, Opioids, Alpha 2 Agonists)
Nitrous Oxide
- MAC > 100%: Incomplete Anesthetic
- Good analgesia
- Rapid onset/recovery
- Safest
- Used in combo w/ other anesthetic
Halothane
- Not Pungent (used for kids)
- Bronchodilator
- Medium rate of onset and recovery
- Sensitizes the heart to epi-induced arrhythmias
SE: Hepatitis
Isoflurane
- Medium rate of onset and recovery
- Induction and maintenance of Anesthesia
- Can induce irregular Arrhythmias
Desflurane
- MOST RAPID ONSET AND RECOVERY OF HALOGENATED GASES
- Outpatient surgery
- Maintenance of Anesthesia
SE: Irritates throat of awake patients, salivation, bronchospasm, cough
Sevoflurane
- Low Blood/Gas coefficient
- Rapid onset and recovery
- Outpatient surgery
- Doesn’t irritate throat
- Bronchodilator
- Useful induction agent (kids)
SE: Nephrotoxicity
Inhaled Pharmokinetics
- DEC BP
- INC RR, DEC TV
- INC Cerebral blood flow
- DEC RBF
- DEC Hepatic Blood Flow
Inhalation Gases SE
- Nephrotoxicity (Methoxy/En/Sevoflurane)
- Malignant Hyperthermia: Mutate RYR, Ca2+ released, Prlonged Ca2+ release = Muscle Rigidity = INC Metabolism = INC Heat
- Normally a genetic disorder but Volatile Liquids can have this effect - Rx: Dantrolene
IV Anesthetics
Barbs BZDs Propafol Etomidate Ketamine Opioids
Barbs
Thiopental, Methohexital
- Can produce unconsciousness and surgical anesthesia in less than 1 min
- Emerge from anesthesia in 10 mins
- DEC in Cerebral metabolism, Oxygen Utilization, Cerebral Blood flow
SE: Porphyria
BZDs
Diazepam, Lorazepam, Midazolam
- Premedication for GA
- Anxiolysis, Amnesia, sedation
- MIDAZOLAM: More rapid, Shorter elimination half life, Inducing agent
Propofol
- Same rate of onset as Barbs but quicker recovery
- Pts feel better post op
- Ambulatory Surgery
- Prolonged sedation in Critical Care
SE: Apnea, Hypotension during induction, Hypotonus, clinical Infxns
Etomidate
- 1 min induction
- Short Duration
- Little Effect on CV and Resp
- Good CV Stability
- Can cause Post-OP Nausea
Opioids
Morphine, Fentanyl, Sufentanil, Alfentanil, Remifentanil
- High dose = Post-Op resp depression
- Remifentanil: Potent but short half life
- Fentanyl Disadvantage = Pt Recall
Neuroleptanalgesia
- State of Analgesia and Amnesia
Fentanyl + Droperidol
Neuroleptanesthesia
Fentanyl + Droperidol + N2O
Ketamine
- Blocks NMDA
- “Dissociative Anesthetic” that makes cataleptic state
- INC HR, BP, CO
- INC Cerebral Blood Flow, oxygen consumption and ICP
SE: Post OP Vivid dreams and illusions
Local Anesthetics: Esters
Benzocaine
Procaine
Dimethocaine
- Metabolized in Plasma cells
Local Anesthetics: Amides
Lignocaine Bupavicaine Mepivicaine Ropovicaine Prilocaine - Metabolized in Liver
Local Anesthetics: Natural
Menthol
Cocaine
Saxitoxin
Local Anesthetics: MOA
- Na+ Inactivation
- Nerve Inactivation
Local Anesthetics: Clinical Use
- Acute Pain
- Chronic Pain
- Invasive Procedures
- Surgery
Local Anesthetics: Routes of Administration
- Topical
- Infiltration
- Block
Local Anesthetics: SE
- Local
- CNS
- CVS
- Hypersensitivity
- Methemoglobinemia
