Can a humid storage environment of surgical instruments before reprocessing increase patient safety and durability of instruments?

BACKGROUND: National and international guidelines recommend reprocessing of medical instruments to commence as soon as possible post-surgery; furthermore, they recommend that transport and storage of surgical instruments postoperatively occurs in a moist, humid atmosphere. The concern is that a dry storage environment results in deterioration of instruments. AIM: To evaluate whether residual protein or corrosion is associated with storage environment (dry or humid), holding time or number of treatment cycles. METHODS: The range of protein residue and corrosion were tested on surgical instruments contaminated with human blood amended Enterococcus faecalis ATCC 29212. Subsequently instruments were stored for 6, 12 and 24 h in dry or humid conditions. After one, 25 and 50 reprocessing cycles, instruments were examined for protein residues using the o-phthaldialdehyde (OPA) method or corrosion using stereomicroscopy, scanning electron microscopy and energy dispersive spectroscopy. FINDINGS: Protein residue found on instruments was 21.5-54.0 µg and corrosion corresponded to 0-5% of the inspected area. No associations between storage environment and protein residue (adjusted mean difference = 0.48, 95% confidence interval: -0.42, 1.37, P=0.30) or corrosion (P=0.20) were identified. Higher numbers of treatment cycles showed higher amounts of corrosion (mean: 1cycle = 0.06%, 25cycles = 0.52% and 50cycles = 1.45%). In contrast, higher numbers of treatment cycles showed lower amounts of protein residue (P<0.001). We found both lower protein residue concentration and lower corrosion rating at 12 h compared with 6 and 24 h holding time. CONCLUSION: Cleanliness and durability of instruments before reprocessing seems not to be affected by storage environment or holding time but instead by number of treatment cycles.

Challenging the six-hour recommendation for reprocessing sterilizable medical equipment.

BACKGROUND: At present, reprocessing of sterilizable medical equipment is recommended to be initiated within 6 h after completion of surgery, to ensure that the quality of the instruments does not deteriorate. A literature search showed a lack of evidence for consequences that may occur if medical personnel deviate from the standard 6 h sterilization protocol. AIM: To evaluate the 6 h recommendation for reprocessing sterilizable medical equipment by determining whether residual protein increased proportional to holding time before reprocessing was initiated, and likewise whether an increase in corrosion was present on surgical scissors proportional to holding time. METHODS: Residual protein was identified on surgical instruments contaminated with human blood after different holding times and before washes using the o-phthaldialdehyde (OPA) method. Corrosion was identified on surgical scissors contaminated with human blood after different holding times and after reprocessing using light stereomicroscopy and scanning electron microscopy. FINDINGS: Protein residues ranged between 14.0 and 51.9 µg and thus below the accepted threshold of 100 µg per instrument surface. Corrosion corresponding to 0.05% of the surface was identified on 22 of 30 scissors. Pitting corrosion was seen on four of 30 scissors. CONCLUSION: No association was identified between residual protein and holding time, nor between incidence of corrosion and holding time. The study thereby challenges the relevance of upholding the recommendation of a maximum wait of 6 h prior to reprocessing. The findings will potentially have an impact on the organization of reprocessing of surgical instruments in Denmark and internationally.

Three-dimensional microstructural properties of regenerated mineralizing tissue after PTH (1-34) treatment in a rabbit tibial lengthening model.

UNLABELLED: Since the approval of parathyroid hormone (PTH) as treatment for osteoporosis, PTH has increasingly been investigated for bone repair and regeneration. The aim of the study was to investigate the effects of intermittent PTH treatment on the microstructure of regenerated mineralizing tissue after distraction osteogenesis in rabbits. After tibial mid-diaphyseal osteotomy the callus was distracted 1 mm/day for 10 days. 72 rabbits were divided in to 3 groups, which daily received a PTH (1-34) 25 microg/kg injection for 30 days; a saline injection for 10 days and a PTH injection for 20 days; or a saline injection for 30 days. The microstructure of the regenerate was assessed by micro computed tomography (microCT). In all 51 obtained specimens were evaluated morphometrically using three different volumes of interests. The results showed that treatment with PTH during distraction osteogenesis resulted in a significantly higher trabecular number, a more isotropic trabecular orientation, a higher connectivity density, and a higher mineralizing tissue mass. We also found that distraction calluses treated with PTH were more mature than the non-treated. CONCLUSION: treatment with PTH resulted in an enhanced microstructure of the newly regenerated mineralizing tissue indicating that PTH has a potential role as a stimulating agent during distraction osteogenesis.