In vitro effects of simulated gastric juice on swallowed metal objects: implications for practical management

Swallowed metal objects often pose a technical challenge for the endoscopist. We studied in vitro the effects of simulated gastric juice on metal objects commonly encountered in endoscopic practice and measured the physical-chemical changes.

Razor blades, disc batteries, and pennies were incubated in simulated gastric juice at 37 degrees C. The weights of the objects were recorded hourly. When no change could be detected, the solution was subjected to mass spectrometry to verify absence of effect. The findings were correlated with clinical observation in one patient who swallowed razor blades repeatedly.

Dissolution of the razor blade was proportional to the duration of acid immersion. At 24 hours, the blades weighed 63% of the original weight. Double-edged razor blades could be broken with a snare at 15 hours. The thickened back of the single-edged blade totally dissolved in 2 hours. No leak of contents could be detected with disk batteries. Pennies were unaffected.

Corrosion of razor blades occurs rapidly in the normal stomach. Within 24 hours double-edged blades become fragile and can be broken with a snare. This observation may guide the timing of endoscopic removal. Modern disk batteries are acid resistant for 24 hours.