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Quantitative analysis of residual protein contamination on reprocessed surgical instruments
R L Baxter1, H C Baxter, G A Campbell
1School of Chemistry, University of Edinburgh, Edinburgh, UK. r.baxter@ed.ac.uk
Abstract:
'Ready-for-use' instruments from surgical instrument trays were examined after routine cleaning and sterilization in a blinded study. These reprocessed instruments originated from five National Health Service hospital trust sterile service departments in England and Wales. Determination of residual protein and peptide contamination was carried out by acid stripping of the instrument surfaces, hydrolysis of the constituent amino acids and quantitative total amino acid analysis. One hundred and twenty instruments were analysed, and the median levels of residual protein contamination per instrument for the individual trays were 267, 260, 163, 456 and 756 microg. Scanning electron microscopy and energy dispersive X-ray spectroscopic analyses of the instruments showed that tissue deposits were localized on surfaces, but there was no significant correlation between overall protein soiling and instrument complexity. The highest levels of residual contamination were found on instruments used for tonsillectomy and adenoid surgery.
Insights
Routine cleaning and sterilization of surgical instruments may leave significant residual protein contamination. Tonsillectomy and adenoidectomy instruments showed the highest contamination levels, indicating a need for improved reprocessing protocols.
Area of Science:
- Surgical Instrument Reprocessing
- Biomedical Engineering
- Hospital Sterilization Practices
Background:
- Surgical instruments undergo cleaning and sterilization between uses to prevent infection transmission.
- Ensuring complete removal of biological debris is critical for patient safety and effective sterilization.
Purpose of the Study:
- To quantify residual protein contamination on 'ready-for-use' surgical instruments after standard reprocessing.
- To investigate the correlation between instrument complexity and protein soiling.
- To identify specific surgical procedures associated with higher contamination levels.
Main Methods:
- Analysis of 120 reprocessed surgical instruments from five National Health Service sterile service departments.
- Quantitative total amino acid analysis following acid stripping and hydrolysis to determine residual protein.
- Scanning electron microscopy and energy dispersive X-ray spectroscopy to visualize and analyze tissue deposits.
Main Results:
- Median residual protein contamination levels varied significantly across instrument trays (163–756 microg per instrument).
- Tissue deposits were localized on instrument surfaces, with no strong correlation between overall protein soiling and instrument complexity.
- Instruments used for tonsillectomy and adenoid surgery exhibited the highest levels of residual contamination.
Conclusions:
- Standard cleaning and sterilization protocols may not fully remove proteinaceous material from surgical instruments.
- Specific surgical procedures, such as tonsillectomy and adenoidectomy, pose a higher risk for instrument contamination.
- Further optimization of reprocessing techniques is necessary to enhance the removal of residual biological material.
