Urinary Alkalinization for Salicylate Poisoning Is Infrequently Measured nor Achieved.

Background: Urinary alkalinization is a key intervention for salicylate poisoning, and clinical guidelines recommend serial urinary pH measurements during treatment.

Study question: How frequently are urine pH measurements obtained, and how often is alkalinization achieved when managing salicylate poisoning with sodium bicarbonate therapy?

Study design: This is a retrospective poison center study. Salicylate cases managed by a regional poison center for a 5-year period (2019-2023) were analyzed. Inclusion criteria included all patients receiving bicarbonate therapy for salicylate concentrations >30 mg/dL that were managed in a health care facility. Patients requiring hemodialysis were excluded to eliminate confounding factors.

Measures and outcomes: The primary outcome was the documentation of a urine pH in the poison center chart. Secondary outcomes included the frequency of urine pH measurements and the achievement of a urinary pH ≥7.5. Data were analyzed using descriptive statistics. Multivariable logistic regression was performed to determine variables associated with increased odds of urine pH measurement.

Results: Among 352 cases, urine pH was documented in 144 (41%). Median urine pH values ranged from 6.0 to 8.5 across serial measurements. Urinary alkalinization (pH ≥7.5) was achieved in 34% of cases with documented urine pH. Higher peak salicylate concentrations were associated with increased odds of urine pH measurement (OR = 1.04, P < 0.001). Verbal recommendations significantly increased the likelihood of pH measurement (OR = 3.43, P < 0.001). Formal guidelines faxed or emailed to clinicians, ICU admission, and toxicology consultation were not significant predictors of urine pH testing.

Conclusions: Urine pH was measured in fewer than half of cases, indicating poor adherence to guidelines recommending urinary pH monitoring during alkalinization therapy. Verbal recommendations were more effective than written guidelines in promoting pH measurement. Further investigation into the clinical utility and adherence barriers of urine pH measurement is warranted.