Influence of drying time on the removal of blood from medical devices

Background

When processing surgical instruments after use, the safe, residue-free removal of blood and blood-containing soiling is one of the most important tasks. There are recommendations from various working groups regarding the ideal timeframe for cleaning used instruments in order to ensure safe disinfection and sterilization and avoid adverse effects. These are generally based primarily on practical experience and there is little systematic work on this topic.

Aim

In the present study, cleaning experiments with test specimens previously contaminated with sheep's blood were performed, and in this way the effects of the drying time of whole blood on the results of the subsequent cleaning were examined.

Methods

Reflecting practice, both visual and spectroscopic methods were used to quantify residual protein. The experimental results were evaluated both as a function of the drying time and the residual moisture of the blood.

Findings

Drying blood was particularly difficult to remove within the first 1–2 h. In this phase, in which the blood is coagulated but not yet completely dried, considerably more protein residues remained on the test specimens after cleaning than after longer standing times.

Conclusion

There is a timeframe for the removal of blood residues in which optimum cleaning results can be expected. As a consequence, there are also standing times that are disadvantageous for reprocessing. Based on the experimental data, it was deduced that this optimum time is either directly after contamination or in the range of >3 h and <24 h after soiling.