Surgery E1: Anesthesia

What are the two types of regional anesthesia?

Spinal and epidural

What is stage 1 (Induction) of anesthesia?

pt is sedate but conversational, breathing is slow, stage ends once pt loses consciousness

What is stage 2 (Excitement) of anesthesia?

pt experiences disinhibition, delirium, uncontrolled movements, HTN, tachycardia

What is stage 3 (surgical) of anesthesia?

ceased eye movements, respiratory depression, divided into 4 “planes”

What is stage 4 (overdose/medullary paralysis) of anesthesia?

occurs when too much anesthetic agent is given, results in severe brain depression, respiratory depression → death

What are absolute contraindications to general anesthesia?

none, only relative (pts w/ difficult airway or significant comorbidities)

Which anesthetics are IV?

Propofol, Etomidate, Ketamine, Dexmedetomidine (precedex), Barbiturates (thiopental) -no longer used in the US

What IV anesthetic has antiemetic actions, rapid onset but short duration, and offers effortless awakening w/ minimal residual sedation?

Propofol

What are SE of propofol?

hypotension, severe acidosis (inc in pts w/ resp infections)

Which IV anesthetic agent is limited to the induction phase and is the agent of choice when CV stability may be a concern?

Etomidate

What are the SE of Etomidate?

pain, phelbitis, inc N/V, adrenocortical suppression, myoclonus, activation of seizure foci

What IV anesthetic is dissociative that distorts perception, produces intense analgesia, and is used for painful beside procedures?

Ketamine

What are the SE of Ketamine?

inc secretions, risk of laryngospasm, inc ICP, dec resp rate, hallucinations, vivid dreams, post-op disorientation

Which IV anesthetic is a selective alpha-2 receptor agonist w/ sedative sympatholytic, and analgesic properties and dec post-op pain and opioid usage?

Dexmedetomidine (Precedex)

What are the SE of Dexmedetomidine?

hypo or hypertension, bradycardia

Which anesthetics are inhaled?

Nitrous oxide, Halothane, -fluranes

Which inhaled anesthetic is an odorless, nonhalogenated agent that creates a state of euphoria, has quick onset, and has potent analgesic properties?

Nitrous oxide (laughing gas)

What are the SE of Nitrous oxide?

diffusion hypoxia, N/V

Which halogenated gas is a potent bronchodilator and is sensitive to catechoamines?

Halothane

Which halogenated gas has less myocardial depression and potential for arrythmias?

Sevoflurane

Which halogenated gas produces inc secretions, cough, laryngospasm, and should be avoided in children w/ asthma?

Desflurane

What are SE of halogenated gases?

malignant hyperthermia, arrythmias, uterine relaxation

Which IV sedative is often used as a premedication for general anesthesia and has potent anxiolytic properties?

Benzodiazepines

Which benzo is most commonly used for pre-op sedation and provides anxiolysis, sedation, and amnesia?

Midazolam (Versed)

Which benzo causes veno-irritation on injection?

Diazepam (Valium)

Which benzo is a LA sedative hypnotic, not commonly used for anesthesia?

Lorazepam (Ativan)

Which opioids are synthetic?

Alfentanil, Sufentanil, Remifentanil, Fentanyl, Meperidine

Which opioids are semi-synthetic?

Hydromorphone, Hydrocodone, Oxycodone

What are SE of synthetic opioids?

respiratory depression, meiosis, bradycardia, constipation, urinary retention, chest wall rigidity

What Non-competitive (depolarizing) NMB mimics the effects of acetylcholine causing fasciculation, prolonged paralysis, and has rapid onset/short duration?

Succinylcholine

What are the SE of succinylcholine?

hyperkalemia, malignant hyperthermia, may cause rhabdo in kids

Which NMB competes w/ acetylcholine at the NMJ, has rapid onset, prolonged duration of action, and CAN be reversed?

competitive (non-depolarizing agents): Atracurium, Cistracurium, Pancuronium, Vecuronium, Rocuronium

Who should you be cautious/avoid use of non-depolarizing neuromuscular blockers in?

Renal or hepatic impaired patients

What are the reversal agents for non-depolarizing neuromuscular blockers?

Neostigmine or Sugammadex

What type of block provides targeted infusion of local anesthetic to block nerve conduction to a specific anatomic or dermatomal region?

Regional block

Where are epidural nerve blocks injected into?

between lumbar, thoracic, or cervical veretebra

Where are spinal nerve blocks injected into?

into CSF of lumbar spine to numb the nerves that exit the spinal cord

When are peripheral nerve blocks used?

procedures that involve a specific extremity or region of the body

When are Intravenous regional anesthesia (Bier block) used?

short-term procedures of forearm/hand, consists of replacing venous blood of arm w/ local anesthetics

What regional anesthesia technique is used for post-op pain in abd procedures?

Transabdominal Plane Block (TAP)

How long should you avoid all other local anesthesia after a TAP?

96 hours after

Which drugs are injectable local anesthetic agents?

Mepivacaine, Lidocaine, Bupivacaine, Ropivacaine, Procaine, Tetracaine, Benzocaine

Which local anesthetic agents are topical?

LAT -lidocaine, epid, tetracaine

TAC -tetracaine, epinephrine, cocaine

EMLA -lidocaine + prolocaine

What is the max dose of Lidocaine?

4 mg/kg; not to exceed 300 mg

What should you NOT use Lidocaine w/ epinephrine for?

digital blocks, nose, or dorsal penile blocks

Which local anesthetic has rapid onset, is injectable and topical, used for anesthesia, sedation, and arrythmias, but may cause drowsiness or low BP?

Lidocaine

Which local anesthetic has slow onset, is used for nerve blocks and surgery, but may cause drowsiness, dec BP, and induce vent. arrhythmias?

Bupivacaine

Which injectable local anesthetic has the longest duration of action?

Bupivacaine

Which local anesthetic has rapid epidural onset, is good for nerve blocks, and causes less drowsiness and amnesia?

Mepivacaine

Which local anesthetic has low potency, low toxicity, rapid epidural onset, but short duration?

Procaine

Which local anesthetic has high potency, is the most toxic, and slow onset?

Tetracaine

Where should you avoid using LAT & TAC?

face, mucous membranes, distal digits, nose, penis, ears

Which topical anesthesic agent is good for post herpetic neuralgia?

Lidocaine

What can you add to a local anesthetic to decrease pain and burning sensation?

Sodium Bicarb

What can be added to local anesthetics to aid in vasoconstriction to keep the anesthetic localized, inc duration, and dec systemic absorption?

Epinephrine

What is a SE of Epinephrine?

transient tachycardia

What is the reversal agent for benzos?

Flumazenil

What is the reversal agent for narcotics?

Narcan