The mechanics of cleaning instruments

Sixty years ago, a chemical engineer from Henkel, Dr Herbert Sinner, came up with a framework describing critical elements of effective cleaning: mechanical action, chemicals, temperature, and time.

Although this concept was proposed for the washing of clothes, it was quickly adopted in other fields of science and industry, including cleaning of surgical instruments. While the concept points out those four critical elements, it also assumes there is a relationship between them. The four elements, like in a pie chart, complete a full circle – Sinner’s Circle. This concept assumes that decreasing effectiveness of one of those elements can be compensated by increasing the role of the others to achieve the same result. 

Sinner’s Circle identifies the critical elements, but the relationship in the case of surgical instruments’ decontamination is far more complicated. When instruments are manually scrubbed, or flushed, technicians are guided by their eyes to remove contamination they see on instruments, and they continue the task until they see contamination gone.