Sodium bicarbonate in 5% dextrose: can clinicians tell the difference?

Background: Due to the lack of double-blind randomised controlled trials, the true effect of intravenous sodium bicarbonate therapy in ICU patients with metabolic acidosis remains unclear. Methods: We diluted 100 mL 8.4% sodium bicarbonate in 150 mL 5% dextrose (D5W) within a 250 mL polyolefin bag after removing 100 mL. We asked ICU clinicians to inspect a 250 mL bag containing sodium bicarbonate or a 250 mL bag where 100 mL of D5W had been removed and then returned. The bags were attached to intravenous giving sets. We asked participants to identify the contents of the bags. Results: Among 60 participants (39 nursing staff [65%], 20 medical staff [33.3%] and one pharmacist), 36 (60%) answered correctly. The Cohen κ for agreement between test bag content and participants’ answers was 0.20 (95% CI, –0.05 to 0.45; P = 0.12), implying the answers were correct by chance. In the group of 28 participants who indicated they used a clue to help them decide their answer, 15 (53.6%) answered correctly, whereas in the remainder (n = 32), 21 (65.6%) answered correctly (P = 0.49). Conclusion: When 100 mL of 8.4% sodium bicarbonate were diluted in 150 mL of D5W within a 250 mL polyolefin bag, clinicians were unable to correctly identify the contents of the bags. Our findings imply that sodium bicarbonate therapy can be successfully blinded.