Common PACU Complications

Respiratory Complications - Airway & Breathing Nightmares

• Upper Airway Obstruction (UAO) 📌 Mnemonic: T-L-E (Tongue, Laryngospasm, Edema)
  • Tongue (most common): Jaw thrust, chin lift, Oropharyngeal/Nasopharyngeal Airway (OPA/NPA).
  • Laryngospasm: Positive Pressure Ventilation (PPV); Suxamethonium (10-20mg IV) if severe.
  • Edema: Steroids, nebulized adrenaline.
• Hypoxemia (SpO2 < 90%)
  • Causes: Atelectasis (most common), Pulmonary Embolism (PE), aspiration, bronchospasm, hypoventilation.
  • Rx: Supplemental O2, treat underlying cause. Incentive spirometry for atelectasis.
• Hypoventilation (Respiratory Rate (RR) < 8-10/min, ↑EtCO2)
  • Causes: Opioids, residual Neuromuscular Blockade (NMB), Central Nervous System (CNS) depression.
  • Rx: Naloxone (0.04-0.4mg IV for opioids), Sugammadex/Neostigmine for NMB, ventilatory support.

⭐ Negative pressure pulmonary edema can occur after acute upper airway obstruction, especially in young, muscular patients.

Cardiovascular Complications - Heart & Vessel Vicissitudes

• Hypotension (SBP < 90 mmHg)
  • Causes: Hypovolemia (bleeding, dehydration), vasodilation (anesthetics, sepsis), ↓ Cardiac Output (MI, tamponade).
  • Management: IV fluids, vasopressors (e.g., phenylephrine, norepinephrine), O2, address underlying cause.

• Hypertension
  • Causes: Pain, anxiety, hypoxia, hypercarbia, bladder distension, shivering, emergence, pre-existing HTN.
  • Management: Analgesia, anxiolytics, O2, antihypertensives (e.g., labetalol 5-20 mg IV, esmolol, nicardipine).
• Arrhythmias (HR < 50 or > 120 bpm)
  • Common: Sinus tachycardia/bradycardia, Atrial Fibrillation (AF), PVCs.
  • Causes: Hypoxia, hypercarbia, electrolyte imbalance (e.g., $K^+$, $Mg^{2+}$), pain, MI, acidosis.
  • Management: Correct cause, O2, antiarrhythmics if unstable; follow ACLS if severe.

⭐ Postoperative myocardial infarction often presents atypically without chest pain, manifesting as hypotension, arrhythmia, or heart failure.

Neurological & Thermal Issues - Brain & Body Shakes

• Delayed Emergence:
  • Causes: Prolonged drug effect (anesthetics, opioids), metabolic (hypoglycemia, electrolytes), neurologic injury (stroke, ↑ICP).
• Postoperative Delirium (POD):
  • Risks: Age, cognitive issues, major surgery, polypharmacy.
  • Features: Acute confusion, inattention, fluctuating.
  • Manage: Treat cause; prevention (orient, mobilize, sleep); haloperidol (0.5-1mg) for agitation.
• Shivering:
  • Causes: Hypothermia, anesthesia, pain.
  • Effects: ↑O2 consumption, ↑CO2, discomfort.
  • Treat: Rewarm; meperidine (12.5-25mg IV), clonidine.
• Hypothermia (Core Temp < 36°C):
  • Causes: Cold OR/fluids, anesthesia.
  • Effects: Coagulopathy, SSI risk, arrhythmias, delayed drug metabolism.
  • Treat: Rewarming (passive/active).

⭐ Shivering can increase oxygen consumption by 200-500%, which can be detrimental in patients with limited cardiorespiratory reserve.

PONV & Pain - Gut Grumbles & Pain Pangs

• PONV (Postoperative Nausea & Vomiting)
  • Risk Factors (Simplified Apfel): 📌 FAME (Female, Anesthesia [volatiles/N₂O, opioids], Motion sickness Hx, Emetic Hx post-op). Score ≥2 = ↑ risk.
  • Prophylaxis: Ondansetron 4mg IV; Dexamethasone 4-8mg IV (after induction).
  • Rescue: Ondansetron 4mg IV.
• Acute Pain
  • Assessment: Pain scales (e.g., NRS, VAS).
  • Multimodal Analgesia: Combine drugs (opioids, NSAIDs, paracetamol) & techniques (regional) for synergistic effect, ↓ side effects.
  • Common Analgesics:
    • Opioids (e.g., Fentanyl, Morphine)
    • NSAIDs (e.g., Ketorolac 30mg IV)
    • Paracetamol 1g IV
  • Regional Techniques: Epidural, peripheral nerve blocks.

⭐ Dexamethasone 4-8mg IV after induction of anesthesia is an effective prophylactic antiemetic with a long duration of action.

High‑Yield Points - ⚡ Biggest Takeaways

• Hypoxemia, often from atelectasis, is most common; ensure patent airway.
• Hypotension frequently stems from hypovolemia or residual anesthesia.
• Pain, anxiety, and bladder distension commonly trigger PACU hypertension.
• PONV risk factors are known; prophylaxis is key for high-risk patients.
• Pain is the primary complaint; use multimodal analgesia for control.
• Shivering increases O2 demand; maintain normothermia with warming.
• Delayed emergence suggests residual drugs, metabolic issues, hypoxia, or pain.