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Phaco and surgeon contamination risks amid COVID-19

Aerosol and spatter generation in some ophthalmic procedures has been a concern during the COVID-19 pandemic, but Kiwi researchers have found no visible contamination above the neckline of cataract surgeons performing phacoemulsification.

In the recent paper published in Clinical and Experimental Ophthalmology, the official journal of RANZCO, Professor Charles McGhee, head of the University of Auckland’s Department of Ophthalmology, and colleagues examined the risk of contamination during routine phaco.

Charles McGhee.

The technique involves high speed instrumentation, a characteristic associated with aerosol generation. Until more evidence is forthcoming, RANZCO has advised phaco may be considered potentially aerosol-generating.

The study, entitled ‘Microdroplet and spatter contamination during phacoemulsification cataract surgery in the era of COVID‐19’, found that even in extreme cases there was no visible contamination of the head, neck or face of the surgeon.

“Therefore, it was unlikely the surgeon or assistants would have contamination of their respiratory system,” McGhee said.

“However, while this was all positive and reassuring, the biggest surprise was just how far spatter could spread onto a surgical gown in the worst-case scenario.”

For the study, the researchers assessed microdroplets and spatter from standardised phacoemulsification of porcine eyes by two ophthalmologists each working with an assistant. The often-minute contamination could only be identified with the inclusion of fluorescein in the phaco irrigating solution and use of blue light.

With phaco instruments fully within the eye, the researchers found spatter contamination was limited to <10 cm. Insertion and removal of the phaco needle and bimanual irrigation/aspiration, with irrigation active, generated spatter on the surgeons’ gloves and gown. It extended to >16 cm below the neckline in the first surgeon and >5.5 cm below the neckline of the second surgeon.

A small tear in the phaco irrigation sleeve – which acted as a worse‐case scenario – created the greatest spatter. However, there was no contamination above the surgeons’ neckline nor contamination of the assistant.

Goggles not necessary 

In their conclusion, the researchers said that until further studies on SARS‐CoV‐2 transmission via microdroplets or aerosolisation of ocular fluid are reported, their pilot study only supported standard personal protective equipment.

McGhee believed there were a few studies pursuing this at present, but there was no conclusive data yet.

He said their results only confirm limited contamination with fluid during phaco but that didn’t necessarily mean the fluid would automatically be contaminated with SARS-CoV2 from ocular surface or intraocular sources. Theoretically, he said this spatter could be largely irrigating fluid – even in an undiagnosed infected patient.

Overall, the study had attracted high interest within and beyond the ophthalmic profession.

“Interestingly, many colleagues have started wearing standard surgical masks again, although they have largely been optional in cataract surgery for nearly 30 years, whilst most are relieved that protective goggles do not appear to be necessary as they are cumbersome to use with operating microscopes,” McGhee said.

“All operating room staff were concerned about aerosol and spatter generation during phacoemulsification in the time of the COVID-19 pandemic, particularly so when we expected we might get many asymptomatic patients, which ultimately has not been the case in New Zealand/Aotearoa.”

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