Gen Surg: Need to Know (Pain and Anesthesia)

Acute Pain

Pain that generally lasts less than 3 months, often due to an identifiable cause

-Causes activation of nociceptors

Chronic Pain

Pain lasting for more than 3 months, which may not have an identifiable cause or due to central sensitization

-Non-pharmacologic is highly important in these patients

NSAIDs, morphine

What two pain medications/classes should be avoided in renal failure?

Acetaminophen

What OTC analgesic should be limited in liver disease?

Acetaminophen

Non-opioid analgesic

-MOA: central COX inhibition

-Uses: baseline analgesic, antipyretic, safe during pregnancy

-ADRs: hepatotoxicity, max dose 4g

-Contraindications: severe liver disease, chronic alcohol use

NSAIDs

Class of non-opioid analgesics

-MOA: COX-1 and COX-2 inhibition, which causes a decrease in prostaglandin release

-Uses: mild-moderate pain, inflammatory pain, and postop

-ADRs: GI bleeding, renal impairment, hypertension

-Contraindications: CKD, ulcers, active bleeding, elderly caution

Ketorolac

IV NSAID

-MOA: potent COX inhibitor

-Uses: strong, short-term analgesic

-ADRs: GI bleed, AKI, platelet inhibition

-Contraindications: Max 5 day use, avoid in renal disease and elderly

Gabapentin

Non-opioid analgesic

-MOA: calcium channel modulation leads to a decrease in neurotransmitter release

-Uses: neuropathic pain, adjunct post-op

-ADRs: sedation, dizziness, ataxia

-Contraindications: elderly, renal adjustment needed

Lidocaine

Used as IV infusion or as a local anesthetic

-MOA: Na channel blockade

-Uses: visceral surgery anesthesia, decrease risk of ileus

-ADRs: tinnitus, perioral numbness, seizurese

-Contraindications: heart block, arrhythmias, liver failure

Ketamine

Non-opioid analgesic

-MOA: NMDA receptor antagonist

-Uses: opioid-sparing, severe post-op pain

-ADRs: dissociation, hallucinations, elevated BP/HR

-Contraindications: CV disease, psych history

Morphine

Third most potent opioid analgesic

-MOA: mu receptor agonist

-Uses: moderate to severe pain

-ADRs: histamine release, leading to pruritus, hypotension, and respiratory depression

-Contraindications: renal impairment

Dilaudid

Second most potent opioid analgesic

-MOA: mu agonist

-Uses: severe pain

-ADRs: histamine release

-Contraindications: use lower doses in opioid-naive and elderly

Fentanyl

Most potent opioid analgesic

-MOA: highly potent mu agonist

-Uses: intraoperative, PACU, rapid analgesia

-ADRs: chest wall rigidity, respiratory depression

Oxycodone

-MOA: mu agonist

-Uses: post-op oral pain control

-ADRs: constipation, sedation

-Avoid in renal/hepatic insufficiency

Hydrocodone

-MOA: mu agonist

-Uses: moderate outpatient pain

-ADRs: N/V, constipation

-Risk of hepatotoxicity when combined with acetaminophen

Codeine

-MOA: weak mu agonist, metabolized to morphine

-Uses: mild pain and cough suppression

-Avoid in children

Tramadol

-MOA: weak mu agonist + SNRI

-Uses: mild to moderate pain, neuropathic component

-ADRs: seizure risk, serotonin syndrome

-Avoid with SSRI/SNRI, seizure disorders

Methadone

-MOA: mu agonist + NMDA antagonist

-Uses: chronic pain

-ADRs: QT prolongation, Torsades de Pointes

-Need EKG monitoring

Alcohol Intoxication

Slurred speech, ataxia, disinhibition

-Respiratory depression if severe

-Tx: thiamine + glucose, supportive care

Alcohol Withdrawal

Tremors, seizures, hallucinations, HTN, tachycardia, delirium tremens

-Tx: CIWA protocol with benzodiazepines

Opioid Intoxication

Euphoria, miosis, respiratory depression, bradycardia

-Tx: naloxone

Opioid Withdrawal

Mydriasis, diarrhea, yawning, piloerection, lacrimation, muscle aches

-Tx: Buprenorphine + clonidine for sx

Stimulant Intoxication

Euphoria, increased energy, mydriasis, tachycardia, HTN, arrhythmias, psychosis

-Tx: benzos

Stimulant Withdrawal

Fatigue, depression, increased appetite, sleep changes

-Tx: supportive care

Cannabis Intoxication

Euphoria, conjunctival injection, increased appetite, impaired coordination

-Supportive care

Cannabis Withdrawal

Irritability, anxiety, sleep difficulty, decreased appetite

-Supportive care

Benzodiazepine Intoxication

Sedation, ataxia, slurred speech, respiratory depression

-Tx: flumazenil

Benzodiazepine Withdrawal

Rebound anxiety, tremors, seizures, agitation

-Tx: long acting benzo taper

Hallucinogen Intoxication

Hallucinations, depersonalization, tachycardia, pupillary dilation

-Tx: supportive

PCP Intoxication

Violent behavior, nystagmus, hypertension

-Benzos for agitation

Inhalants

Euphoria, dizziness, slurred speech, rash around mouth

-Supportive care, watch for arrhythmias

MDMA Intoxication

Euphoria, empathy, hyponatremia, hyperthermia

-Fluid correction, cooling, benzos

Local Infiltration

Direct injection into tissue

-Uses: skin excision, laceration repair

Peripheral nerve block

Injection near nerve plexus

-Uses: upper/lower limb surgery

Spinal Anesthesia

Injection into CSF

-Uses: C-sections, lower abdomen, lower extremity

Intralipid

A patient presents with tinnitus and a metallic taste in their mouth after receiving bupivacaine. What is the treatment of choice, considering the most likely diagnosis?

Dantrolene

What agent do you use to treat malignant hyperthermia, as a result of inhaled anesthetics?