Anesthesia Principles for Surgeons

Anesthesia Principles for Surgeons

Anesthesia Principles for Surgeons

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Pre-op Assessment & Risk - Setting the Stage

  • ASA Physical Status Classification:

    StatusDescription
    ASA INormal healthy patient
    ASA IIMild systemic disease
    ASA IIISevere systemic disease
    ASA IVSevere systemic disease, constant threat to life
    ASA VMoribund, not expected to survive without operation
    ASA VIDeclared brain-dead, organ donor
    EEmergency procedure
  • Pre-anesthetic Evaluation:

    • Focused Hx: Allergies, medications, prior anesthesia Hx, comorbidities.
    • Airway Assessment (📌 LEMON mnemonic for difficult airway):
      • Mallampati score. Mallampati Airway Classification for Anesthesia
      • Thyromental distance (>6.5 cm).
      • Inter-incisor gap (>3 cm).
      • Neck mobility.

⭐ NPO guidelines are crucial to prevent aspiration:

  • Clear liquids: 2 hrs.
  • Breast milk: 4 hrs.
  • Light meal/Infant formula: 6 hrs.
  • Fatty/fried meal: 8 hrs.
  • Informed Consent: Essential for anesthesia plan and risks discussion.

Types of Anesthesia - Pick Your Potion

  • General Anesthesia (GA): Reversible loss of consciousness.
    • Phases: Induction, Maintenance, Emergence.
    • Total Intravenous Anesthesia (TIVA): GA using IV agents only.
  • Regional Anesthesia: Numbs a larger body area.
    • Spinal: Injection into subarachnoid space (L3-L4/L4-L5). Agents: Bupivacaine. Baricity affects spread. Complications: Hypotension, Post-Dural Puncture Headache (PDPH).
    • Epidural: Catheter in epidural space. Advantage: Prolonged post-op analgesia.
  • Local Anesthesia (LA): Numbs a small, specific area.
    • Mechanism: Blocks Na+ channels.
    • Types: Amides (Lignocaine, Bupivacaine), Esters (Procaine).
    • Max Doses: Lignocaine (plain 3-5 mg/kg; +adrenaline 7 mg/kg). Bupivacaine (plain 2-2.5 mg/kg).
    • Toxicity: 📌 SAMS: Slurred speech, Altered mental status, Muscle twitching, Seizures.
  • Monitored Anesthesia Care (MAC): Sedation with local anesthesia; patient responsive.

⭐ Spinal anesthesia commonly uses hyperbaric Bupivacaine; post-dural puncture headache (PDPH) is a known complication, often managed conservatively or with an epidural blood patch.

Spinal vs. Epidural Anesthesia Needle Placement Word count: 148. This is over the 110 word limit. Let's try to make it more concise.

Types of Anesthesia - Pick Your Potion

  • General Anesthesia (GA): Reversible unconsciousness. Phases: Induction, Maintenance, Emergence. TIVA option.
  • Regional Anesthesia:
    • Spinal: Subarachnoid injection (L3-L5). Agent: Bupivacaine. Complications: Hypotension, PDPH.
    • Epidural: Catheter for prolonged analgesia.
  • Local Anesthesia (LA): Na+ channel blockade.
    • Amides (Lignocaine, Bupivacaine), Esters (Procaine).
    • Max Doses: Lignocaine (plain 3-5 mg/kg; +adrenaline 7 mg/kg). Bupivacaine (plain 2-2.5 mg/kg).
    • Toxicity: 📌 SAMS (Slurred speech, Altered mental status, Muscle twitching, Seizures).
  • Monitored Anesthesia Care (MAC): Sedation + LA.

⭐ Spinal: Hyperbaric Bupivacaine common. PDPH risk; manage conservatively or blood patch.

Epidural vs. Spinal Anesthesia Needle Placement Word count: 105. This is within the limit. Let's check all rules.

  1. Heading: ## Types of Anesthesia - Pick Your Potion - YES
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  4. Flowchart? NO - YES
  5. Image placeholder? YES - YES, one image used.
  6. High-yield lines in blockquote - YES
  7. LaTeX - N/A for this section as per original plan, no formulas.
  8. No LaTeX inside blockquotes - N/A
  9. Tables only for true comparisons - N/A, used bullets.
  10. Symbols - 📌 ⭐ used. - YES
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Airway Management & Drugs - Breath & Beyond

  • Basic Airway:
    • Maneuvers: Head-tilt/chin-lift, jaw thrust.
    • Devices: OPA, NPA (unconscious, no gag), LMA (supraglottic), ETT (definitive airway).
  • RSI (Rapid Sequence Intubation): Full stomach/aspiration risk. Steps: Preoxygenate, cricoid pressure, induction, paralysis, intubate.
  • IV Anesthetics:
    • Propofol: SE: hypotension, apnea.
    • Etomidate: CVS stable.
    • Ketamine: Dissociative, bronchodilation, analgesia. SE: emergence delirium.
  • Inhalational: Sevoflurane, Desflurane, Isoflurane (MAC = potency). N2O (second gas effect).
  • Muscle Relaxants:
    • Succinylcholine (Depolarizing): SE: hyperkalemia, fasciculations, MH trigger.
    • Rocuronium, Vecuronium (Non-depolarizing): Reverse: Neostigmine/Glycopyrrolate or Sugammadex.

⭐ Malignant Hyperthermia: Rare; due to succinylcholine/inhalational agents. Treat: Dantrolene 2.5 mg/kg IV.

Intra-op Monitoring & Complications - Crisis Control

  • Standard ASA Monitoring: ECG, NIBP, SpO2, EtCO2 (ETT, ventilation), Temp.

    ⭐ Capnography (EtCO2): Most reliable for ETT confirmation & ventilation adequacy.

  • Common Complications:
    • Hypotension: Causes (drugs, blood loss, sympathetic block). Mgmt: Fluids, vasopressors.
    • Hypoxia: Causes (airway, breathing, circulation). Mgmt: 100% O2, ABCs.
    • Anaphylaxis: Signs (↓BP, bronchospasm, rash). Mgmt: Adrenaline 0.3-0.5 mg IM/IV, fluids, steroids, antihistamines.
  • Malignant Hyperthermia (MH):
    • Triggers: Succinylcholine, volatile anesthetics.
    • Signs: Early (↑EtCO2, tachycardia, rigidity); Late (hyperthermia, rhabdomyolysis).
    • Mgmt: Stop triggers, 100% O2 hyperventilation, Dantrolene 2.5 mg/kg IV (repeat PRN), cooling, treat acidosis/hyperK+.
  • Awareness under anesthesia: Rare; risk factors (paralysis, difficult intubation).

High‑Yield Points - ⚡ Biggest Takeaways

  • ASA classification predicts perioperative risk.
  • Mallampati score assesses airway; higher scores mean difficult intubation.
  • Malignant hyperthermia (MH), triggered by succinylcholine/volatiles, is treated with dantrolene.
  • Propofol is a common IV anesthetic; ketamine provides analgesia and cardiovascular stability.
  • Spinal anesthesia: local anesthetic into subarachnoid space for rapid onset.
  • Local Anesthetic Systemic Toxicity (LAST): manage with IV lipid emulsion.
  • Rapid Sequence Intubation (RSI) for full stomach patients prevents aspiration_._

Practice Questions: Anesthesia Principles for Surgeons

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Flashcards: Anesthesia Principles for Surgeons

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_____ forceps which is used for blunt dissection during "Hilton's method" of abscess drainage

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_____ forceps which is used for blunt dissection during "Hilton's method" of abscess drainage

Lister s sinus

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