A Positive Cocaine Urine Toxicology Test and the Effect on Intraoperative Hemodynamics Under General Anesthesia.

BACKGROUND: Cocaine has a short biological half-life, but inactive urine metabolites may be detectable for a week following use. It is unclear if patients who test positive for cocaine but have a normal electrocardiogram and vital signs have a greater percentage of hemodynamic events intraoperatively. METHODS: A total of 328 patients with a history of cocaine use who were scheduled for elective noncardiac surgery under general anesthesia were enrolled. Patients were categorized into cocaine-positive versus cocaine-negative groups based on the results of their urine cocaine toxicology test. The primary aim of this study was to evaluate whether asymptomatic cocaine-positive patients had similar percentages of intraoperative hemodynamic events, defined as (1) a mean arterial blood pressure (MAP) of <65 or >105 mm Hg and (2) a heart rate (HR) of <50 or >100 beats per minute (bpm) compared to cocaine-negative patients. The study was powered to assess if the 2 groups had an equivalent mean percent of intraoperative hemodynamic events within specific limits using an equivalence test of means consisting of 2 one-sided tests. RESULTS: The cocaine-positive group had a blood pressure (BP) that was outside the set limits 19.4% (standard deviation [SD] 17.7%) of the time versus 23.1% (SD 17.7%) in the cocaine-negative group (95% confidence interval [CI], 0.5-7.0). The cocaine-positive group had a HR outside the set limits 9.6% (SD 16.2%) of the time versus 8.2% (SD 14.9%) in the cocaine-negative group (95% CI, 4.3-1.5). Adjusted for age, sex, body mass index (BMI), smoking status, and the presence of comorbid hypertension, renal disease, and psychiatric illness, the cocaine-positive and cocaine-negative patients were similar within a 7.5% margin of equivalence for MAP data (ß coefficient = 2%, P = .003, CI, 2-6) and within a 5% margin of equivalence for HR data (ß coefficient = 0.2%, P < .001, CI, 4-3). CONCLUSIONS: Asymptomatic cocaine-positive patients undergoing elective noncardiac surgery under general anesthesia have similar percentages of intraoperative hemodynamic events compared to cocaine-negative patients.

Recent cocaine use and the incidence of hemodynamic events during general anesthesia: A retrospective cohort study.

STUDY OBJECTIVE: To evaluate the intraoperative hemodynamics and medication requirements of cocaine-positive patients compared to matched cocaine-negative controls. DESIGN: Retrospective cohort study. SETTING: Public county hospital. PATIENTS: 821 patients undergoing general anesthesia. MEASUREMENTS: Incidence of hemodynamic events, defined by a mean arterial pressure of <65 mmHg or >105 mmHg or a heart rate of <50 beats per minute or >100 beats per minute. MAIN RESULTS: Cocaine-positive patients did not experience a higher incidence of hemodynamic events when compared with matched cocaine-negative patients. Cocaine-positive patients were not more likely to be administered vasopressors intraoperatively but did receive more anti-hypertensive agents. The minimum alveolar concentration of anesthetics used was similar between the two groups. Anesthesia duration, length of stay, and in-hospital mortality did not significantly differ between the two cohorts. CONCLUSIONS: Cocaine-positive patients did not demonstrate more intraoperative hemodynamic events or adverse short-term outcomes as compared to matched cocaine-negative controls.

The influence of morbid obesity on difficult intubation and difficult mask ventilation.

PURPOSE: To determine the influence of morbid obesity on the incidence of difficult mask ventilation and difficult intubation. METHODS: Over a 6-year period, all tracheal intubations in the operating room of a large tertiary teaching hospital were analyzed. A modified version of the intubation difficulty scale (mIDS) was used to define easy versus difficult intubation, where a score of two or greater was defined as difficult intubation. Difficult mask ventilation was defined as the use of one or more adjuncts to achieve successful mask ventilation. RESULTS: Of 45,447 analyzed cases, 1893 (4.2%) were classified as difficult intubations. Morbidly obese patients were not more likely to have difficult intubation [Odds Ratio (OR) = 1.131, 95% confidence interval (CI): 0.958, 1.334, p = 0.146]. Factors that were associated with difficult intubation included patient age > 46 years, male sex, Mallampati 3-4, thyromental distance < 6 cm, and the presence of intact dentition. Of 37,016 cases in which mask ventilation was attempted, 1069 (2.9%) were difficult. Morbidly obese patients were more likely to have difficult mask ventilation (OR = 3.785, 95% CI: 3.188, 4.493, p < 0.0001). Other factors associated with difficult mask ventilation included patient age > 46 years, male sex, Mallampati 3-4, and a history of obstructive sleep apnea. Having intact dentition decreased the likelihood of difficult mask ventilation. CONCLUSION: Morbidly obese patients do not have a higher incidence of difficult intubation compared to non-morbidly obese patients. However, they have a significantly higher incidence of difficult mask ventilation. Other factors that are predictive of both difficult mask ventilation and difficult intubation include age > 46 years, male sex, and Mallampati 3-4.