Hemodynamic Effects of Methamphetamine and General Anesthesia.

Area of Science:

• Anesthesiology
• Pharmacology
• Toxicology

Background:

• Perioperative methamphetamine use is a growing concern.
• Understanding its impact on intraoperative stability is crucial for patient safety.

Purpose of the Study:

• To assess the risk of intraoperative hemodynamic instability in patients with recent methamphetamine use.
• To compare instability rates between acutely positive, subacutely positive, and methamphetamine-negative surgical patients.

Main Methods:

• Retrospective analysis of anesthetic records for patients undergoing surgery under balanced anesthesia.
• Patients categorized into three groups: acute methamphetamine positive (within 48 hours), subacute (48 hours to 7 days), and controls (negative).
• Hemodynamic instability defined by significant MAP drop or vasopressor requirement.

Main Results:

• 31.4% of acutely methamphetamine-positive patients experienced hemodynamic instability within the first hour of anesthesia.
• Subacutely positive patients had a 26.1% instability rate, compared to 6.3% in controls.
• Instability occurred despite lower anesthetic doses in methamphetamine-using groups.

Conclusions:

• Positive urine drug screens for amphetamines within 2 days of surgery indicate increased risk of hemodynamic instability.
• Postponing surgery to 7 days may mitigate but not normalize this risk compared to non-users.