Gastric lavage with normal saline: effects on serum electrolytes

The aim of this study is to determine the intensity of changes in serum calcium, ionized calcium, and magnesium levels after gastric lavage with normal saline in patients with amitriptyline intoxication.

In this study, thirty patients older than 16 years with the history of intoxication with amitriptyline were included. After the baseline serum calcium, ionized calcium, and magnesium levels had been measured, gastric lavage with normal saline was performed. Serum levels of calcium, ionized calcium, and magnesium were monitored at 15 minutes, 6 hours, and 12 hours.

Serum calcium levels decreased significantly from 9.32 +/- 0.47 mg/dL to 8.40 +/- 0.61 mg/dL (15 minutes, p < 0.001), 8.92 +/- 0.54 mg/dL (6 hours, p < 0.001), and 8.93 +/- 0.54 mg/dL (12 hours, p < 0.001). Serum ionized calcium levels decreased significantly from 1.26 +/- 0.10 mmol/L to 1.20 +/- 0.07 mmol/L (15 minutes, p = 0.004), 1.21 +/- 0.08 mmol/L (6 hours, p = 0.024), and 1.21 +/- 0.08 mmol/L (12 hours, p = 0.034). Serum magnesium levels decreased from 2.41 +/- 0.43 mg/dL to 2.04 +/- 0.25 mg/dL (15 minutes, p < 0.001), 2.14 +/- 0.26 mg/dL (6 hours, p < 0.001), and 2.16 +/- 0.25 mg/dL (12 hours, p < 0.001).

Our study demonstrated that gastric lavage with normal saline can cause a statistically significant decrease in serum calcium, ionized calcium, and magnesium (Fig. 4, Ref. 8).