Use of an Ultra-clean Air Flow for Surgical Field Asepsis when Performing Intravitreous Injections in an Ambulatory Surgical Environment

Background: Intravitreal injection of medications is one of the most common procedures performed in ophthalmology. Intravitreal anti-VEGF agents are currently the chosen treatment for ocular fundus diseases, including age-related macular degeneration and diabetic retinopathy. As an invasive procedure it involves risks. The most serious complication from intravitreal injection of anti-VEGF agents is endophthalmitis (EO). Although rare, EO can result in devastating loss of vision. This article evaluates whether the use of an ultra-clean air flow (UA) can be another useful tool in the prevention of EOs. Accordingly, the maintenance of asepsis of the surgical field of intravitreal injections was verified with and without the use of UA.

Methods: The study was conducted in operating room of an ambulatory surgery center on four different surgical days when just intravitreal injections were scheduled. Two experiments using two Blood Agar and two Chocolate Agar plates (first 2 days; 4 plates by day) were carried out by positioning an UA directed to the surgical table and two other experiments (last 2 days; 4 plates per day) were carried out using similar plates without the use of the UA. All Blood Agar and four Chocolate Agar plates were positioned on the surgical table, close to the surgical filed. At the end of the day, after the conclusion of the intravitreous injections, the plates were sent for a biomolecular study that was carried out after 1 day of incubation at 37 °C.

Results: The sixteen plates, eight Blood Agar and eight Chocolate Agar, were analyzed qualitatively for the growth or not of microorganism's colonies and identification of their species. The biomolecular study demonstrated the growth of bacteria of the genus Micrococcus sp. with the use of the UA and without the the UA bacterias of the genera Bacillus sp, Staphylococcus haemolyticus, Staphylococcus aureus and Staphylococcus cohnii ssp urealyticus were found.

Conclusion: The use of UA close to the operating table prevented the growth of pathogenic bacteria and should be considered as an alternative tool to avoid the contamination of materials and drugs used for intravitreal injections.