How does cocaine use affect anesthesia administration?

Cocaine's Effects on Anesthesia Administration

Cocaine use significantly impacts anesthesia administration by increasing cardiovascular risks, altering drug responses, and requiring specific management strategies to prevent life-threatening complications. 1

Pathophysiological Effects of Cocaine

Cocaine affects multiple systems relevant to anesthesia:

Cardiovascular Effects

• Blocks sodium and potassium channels in cardiac tissue, causing:
  • QRS prolongation
  • QT interval prolongation
  • Wide-complex tachycardias
  • Potential for ventricular arrhythmias including VT and VF 1
• Inhibits catecholamine reuptake, leading to:
  • Hypertension (via α-adrenergic stimulation)
  • Tachycardia (via β-adrenergic stimulation)
  • Coronary vasospasm
  • Increased myocardial oxygen demand 1
• Increases platelet aggregation, promoting thrombosis 1

Other Relevant Effects

• Hyperthermia due to hypermetabolism 1
• Impaired myocardial contractility 1
• Local anesthetic properties (sodium channel blockade) 1

Anesthetic Management Considerations

Preoperative Assessment

• Evaluate for signs of acute intoxication: tachycardia, hypertension, hyperthermia, agitation
• Check ECG for conduction abnormalities (QRS widening, QT prolongation)
• Assess for evidence of end-organ damage (myocardial ischemia, renal dysfunction)
• Consider delaying elective procedures in patients with acute intoxication 2

Intraoperative Management

Cardiovascular Management

• Avoid β-blockers as they may worsen coronary vasospasm by leaving α-adrenergic effects unopposed 1
• Preferred agents for hypertension/tachycardia:
  • Benzodiazepines (first-line for agitation and sympathetic stimulation)
  • Calcium channel blockers (e.g., diltiazem) for coronary vasospasm
  • Nitroglycerin for coronary vasospasm and hypertension
  • Phentolamine (α-blocker) for severe hypertension 1
• For ventricular arrhythmias:
  • Sodium bicarbonate (1-2 mEq/kg) is recommended 1
  • Lidocaine can be used despite theoretical concerns about additive toxicity 1

Temperature Management

• Aggressively treat hyperthermia with active cooling methods 1
• Evaporative or immersive cooling is more effective than cooling blankets 1

Anesthetic Agent Selection

• General anesthesia considerations:
  • Inhalational agents may exacerbate myocardial depression
  • Ketamine may worsen sympathetic stimulation
  • Opioids and benzodiazepines are generally safe options 3
• Regional anesthesia considerations:
  • May be appropriate if coagulopathies are ruled out
  • Be cautious with maximum doses of local anesthetics due to potential additive toxicity 3

Special Considerations

Chronic Cocaine Users

• May experience unexpected hypotension during anesthesia due to catecholamine depletion
• Direct-acting vasopressors (phenylephrine, norepinephrine) are more effective than indirect-acting agents 2
• May have baseline cardiac abnormalities including left ventricular hypertrophy or cardiomyopathy 4

Acute Toxicity Management

• For wide-complex tachycardia or cardiac arrest: sodium bicarbonate (1-2 mEq/kg) 1
• For hyperthermia: rapid external cooling 1
• For coronary vasospasm: nitroglycerin, calcium channel blockers 1

Pitfalls and Caveats

1. Avoid β-blockers (including labetalol) which can worsen coronary vasospasm through unopposed α-adrenergic effects 1

2. Monitor for unexpected hypotension in chronic users due to catecholamine depletion 2

3. Be cautious with local anesthetics due to potential additive toxicity with cocaine (both are sodium channel blockers) 3

4. Watch for arrhythmias during anesthesia induction and maintenance due to cocaine's effects on cardiac conduction 1

5. Anticipate difficult hemodynamic control with potential for rapid swings between hypertension and hypotension 3