Hemodynamic Effects of Methamphetamine and General Anesthesia.

Design: A retrospective analysis of all anesthetic records at our institution over a two-year period was performed. Setting . Operating room cases under balanced anesthesia. Patients . All patients with ASA class I or II, who did not have trauma or were initially admitted to ICU, aged 18-65, without preexisting cardiac, renal, or pulmonary disease. Patients were divided into three groups: those acutely positive for methamphetamine within 48 hours of surgery ( n  = 137), those positive for methamphetamine between 48 hours and 7 days of surgery ( n  = 69), and randomly selected controls who were negative for methamphetamine within 7 days of surgery ( n  = 159). Measurements . Intraoperative hemodynamic instability was defined as either a drop of more than 40% in MAP for greater than 5 minutes or requirement for significant amount of vasopressors. Main Results . Among the patients who were acutely positive for methamphetamine within 24 hours, 31.4% met the criteria for hemodynamic instability within the first hour of general anesthesia, compared to 26.1% of the subacutely positive patients and 6.3% of controls ( p < 0.0001). This was despite lower doses of anesthetic medications in the acutely and subacutely positive groups.
Conclusion: Patients who present to the operating room with a positive urine drug screen for amphetamines within 2 days of surgery are at increased risk of hemodynamic instability. Postponing surgery up to 7 days somewhat decreases this risk, but not to the levels of patients who do not use methamphetamines.
Competing Interests: The authors declare that they have no conflicts of interest.
(Copyright © 2022 Keyvan M. Safdari et al.)