Focused Use of Drug Screening in Overdose Patients Increases Impact on Management

Abstract

Drug poisoning is a common cause for attendance in the emergency department. Several toxicology centres suggest performing urinary drug screens, even though they rarely influence patient management.

STUDY OBJECTIVES:

Measuring the impact on patient management, in a University Emergency Department with approximately 40,000 admissions annually, of a rapid urinary drug screening test using specifically focused indications. Drug screening was restricted to patients having a first psychotic episode or cases demonstrating respiratory failure, coma, seizures, a sympathomimetic toxidrome, severe opiate overdose necessitating naloxone, hypotension, ventricular arrhythmia, acquired long QT or QRS >100 ms, and high-degree heart block.

METHODS:

Retrospective analysis of Triage® TOX drug screen tests performed between September 2009 and November 2011, and between January 2013 and March 2014.

RESULTS:

A total of 262 patients were included, mean age 35 ± 14.6 (standard deviation) years, 63% men; 29% poisoning with alcohol, and 2.3% deaths. Indications for testing were as follows: 34% were first psychotic episodes; 20% had acute respiratory failure; 16% coma; 8% seizures; 8% sympathomimetic toxidromes; 7% severe opioid toxidromes; 4% hypotension; 3% ventricular arrhythmias or acquired long QT intervals on electrocardiogram. A total of 78% of the tests were positive (median two substances, maximum five). The test resulted in drug-specific therapy in 6.1%, drug specific diagnostic tests in 13.3 %, prolonged monitoring in 10.7% of methadone-positive tests, and psychiatric admission in 4.2%. Overall, 34.3% tests influenced patient management.

CONCLUSIONS:

In contrast to previous studies showing modest effects of toxicological testing, restricted use of rapid urinary drug testing increases the impact on management of suspected overdose patients in the ED.

Below:  Indications for urinary drug screening (n = 369) in 262 patients.

Arrhythmia or long QT = QT prolongation >480 ms, or ventricular tachycardia or flutter, or torsade de pointes tachycardia; Hypotension = systolic hypotension (<80 mm Hg); Opiate toxidrome = if requiring antagonist administration; Psychosis = first psychotic episode; Resp failure = acute respiratory failure (pCO₂ 45‑80 mm Hg or emergency intubation); Sympathomimetic = clinical signs of sympathomimetic toxicity

Below:  Spectrum of substances detected with the Triage^® TOX screen (204 positive urine samples with 348 substances detected). AMP = amphetamines; BAR = barbiturates; BZO = benzodiazepines; COC = cocaine; MAMP = metamphetamines; MTD = methadone; OPI = opiates; PAR = paracetamol; TCA = tricyclic antidepressants; THC = tetrahydrocannabinoids

Below:  Impact of test results on clinical decisions (in %, n = 90) consecutive to the detection of substances with the Triage^®TOX drug screen (n = 262 tests). Toxin-specific administration of naloxone, flumazenil or N-acetycysteine or other drug-specific treatments after test results.

Diagnostic tests = drug-related diagnostic tests ordered after test result; disposition = psychiatry transfer influenced by negative screening / somatic transfer if positive; prolonged monitoring = longer monitoring when methadone positive

Full article at:   http://goo.gl/MGRtlR

By:   Erdmann A1, Werner D2, Hugli O3, Yersin B3.

• 1Emergency Department, University Hospital (CHUV), Lausanne, Switzerland; Angiology Department, University Hospital (CHUV), Lausanne, Switzerland.
• 2Laboratory of clinical chemistry, University Hospital (CHUV), Lausanne, Switzerland.
• 3Emergency Department, University Hospital (CHUV), Lausanne, Switzerland.
• Swiss Med Wkly. 2015 Dec 28;145:w14242. doi: 10.4414/smw.2015.14242. eCollection 2015.
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