The effect of simulated gastric juice on the surface characteristics and mechanical properties of nasogastric feeding tubes

We studies the surface characteristics and mechanical properties of four brands of poly(ether urethane) feeding tubes incubated for eight weeks at 37°C in simulated gastric juice. Surface degradation was characterized by scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS). Changes in mechanical properties were monitored with an Instron tester. All four brands were found to contain an X-ray opaque filler (BaSO₄ or Bi₂S₃). Incubation in the simulated gastric juice caused some surface degradation of three of the brands. This was demonstrated by the presence of small holes from which filler particles had dislodged. The ultimate tensile strength (UTS) and the elongation at break of Silk tubes were unaffected by the incubation. Incubated Keofeed tubes showed a 12% in elongation at break but no change in UTS. Incubated Entriflex tubes had a 15% lower UTS while their elongation was unaffected