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[Sterilization of phacoemulsification and vitrectomy instruments. Contamination and evaluation]
H Minõ de Kaspar1, T Grasbon, A Kampik
1Augenklinik der Ludwig-Maximilians-Universität München.
Background:
Contamination of automated surgical equipment is widely disregarded as a potential source of perioperative infection. We investigated the possibility of contamination of the aspiration fluid by the vacuum control manifold (VCM). The normal, unsterile internal VCM was compared with a modified external VCM that was regularly disinfected.
Materials And Methods:
We investigated 37 aspiration fluid specimens from routine cataract and vitrectomy operations performed with automated evacuation systems. There were 25 specimens from three automated evacuation systems equipped with an internal VCM (experimental groups) and 12 specimens from one system equipped with a modified external VCM (control group). No hygiene procedures were used with the hidden internal VCM, but the modified external VCM was regularly rinsed and filled with 70% isopropanol overnight. Specimens were collected under sterile conditions, centrifuged, cultured for bacterial growth on blood agar and MacConkey agar for 24-48 h at 37 degrees C, and analyzed microbiologically.
Results:
Aspiration fluids of irrigation/aspiration systems used for intraocular surgery were found to be severely contaminated with bacteria originating from the VCM. In all aspiration fluid specimens from internal VCM systems, 2(+)-4+ bacterial growth was found. Stenotrophomonas maltophilia (17), Comamonas acidovorans (8), and Agrobacterium radiobacter (13) were found most frequently. All specimens from the modified external VCM system remained sterile. There was a significant difference with regard to the frequency of contamination of the aspiration fluid between experimental and control groups (P = 0.0001, chi 2).
Conclusions:
We found that the aspiration fluid of common phaco- and vitrectomy systems was strongly contaminated by bacteria originating from the internal VCM. The technical modification of an external VCM allows easy disinfection and prevents contamination of the aspiration fluid.
Insights
Contaminated surgical equipment can cause infections. An internal vacuum control manifold (VCM) in surgical systems showed severe bacterial contamination, while a modified external VCM remained sterile, preventing infection risk.
Area of Science:
- Ophthalmology
- Microbiology
- Surgical Technology
Context:
- Automated surgical equipment, particularly the vacuum control manifold (VCM), is a potential but often overlooked source of perioperative infections.
- Internal VCMs in common phaco- and vitrectomy systems are not routinely disinfected, creating a reservoir for bacterial growth.
Purpose:
- To investigate the contamination of aspiration fluid by the vacuum control manifold (VCM) in automated surgical equipment.
- To compare the bacterial contamination levels between a standard internal VCM and a modified, externally accessible VCM that allows for regular disinfection.
Summary:
- A study of 37 aspiration fluid specimens from intraocular surgeries revealed severe bacterial contamination (2-4+ growth) in all samples from systems with internal VCMs.
- Common bacteria identified included Stenotrophomonas maltophilia, Comamonas acidovorans, and Agrobacterium radiobacter.
- Aspiration fluid from a system with a modified external VCM, regularly disinfected with 70% isopropanol, remained completely sterile.
- A statistically significant difference (P = 0.0001) in contamination frequency was observed between the internal and external VCM groups.
Impact:
- The findings highlight the critical need for improved hygiene protocols for automated surgical equipment to prevent perioperative infections.
- Modifying the VCM to an external, easily disinfected design effectively eliminates aspiration fluid contamination.
- This research provides a practical solution for enhancing patient safety in ophthalmic surgery by mitigating infection risks associated with contaminated equipment.