News|Articles|September 26, 2025

Novel ventilator is used to perform eye surgery on sea lions

Fact checked by: Kristen Coppock Crossley, MA

Darvall, a producer of veterinary anesthesia solutions based in Sydney, Australia, has developed an innovative new ventilator that enabled surgeons to successfully achieve cataract surgery on 2 sea lions.

Advancement in veterinary anesthesia could lead to saving the lives of diving mammals kept in captivity. Darvall, a producer of veterinary anesthesia solutions based in Sydney, Australia, has developed an innovative new ventilator that enabled surgeons to successfully achieve cataract surgery on 2 sea lions at Coffs Coast Wildlife Sanctuary (CCWS) in New South Wales, Australia.¹

Cataracts are an increasingly common challenge in sea lions, an endangered species, as they are living longer when housed in sanctuaries and therefore develop age-related eye disease. Left untreated, blindness in sea lions can quickly lead to starvation because of the inability to hunt.¹

The surgeries, performed on Miri (60kg female) and Ozzie (200kg male), were led by an international team of veterinary experts in ophthalmology and marine mammal anesthesia, in partnership with CCWS staff and SeaWorld technical specialists. Both sea lions recovered smoothly, regaining vision and quality of life.¹

The first of its kind in marine mammal anesthesia, the novel ventilator used for the surgeries is compact and portable. It is designed to replicate the unique breathing pattern of diving mammals, and has proved crucial in maintaining safe, stable anesthesia during the complex procedures. According to Darvall, traditional anesthesia systems rely on bulky equipment and high volumes of compressed gas.¹

“Inhalant anesthetics are potent greenhouse gases, so we do worry about the impact of those gasses in our environment…Even though we think about inhaling anesthetics as being gas or eliminated [into] and affecting the air, [they] do have an effect on the water as well,” Tatiana Henriques Ferreira, DVM, PhD, MSc, DACVAA, said in a dvm360 interview at the 2025 North American Veterinary Community SkillShop in Orlando, Florida.²

Darvall’s new ventilator is the size of a backpack, and delivers a sustainable solution that reduces inhalant anesthetic use by up to 5 times, lowering both environmental impact and operational cost, according to the company. “Having a system that can both mimic the natural breathing cycle of marine mammals and run independently off bottled driving gas represents a step change. The new ventilator makes these high-risk procedures safer, more sustainable, and far more accessible,” Colin Dunlop, BVSc, DACVAA, founder and CEO of Darvall, said in a news release.¹

For CCWS, a not-for-profit conservation and education center, the milestone underscores the power of innovation and collaboration. “It was a privilege to be part of a world-first. Cataract surgery in sea lions is a massive risk, but Darvall’s ventilator proved safer, simpler, quieter and more portable than anything we’ve used before. This gives our animals the best chance, and it’s exciting to think this one-of-a-kind machine could help other marine animals around the world,” Tiga Cross, managing director at CCWS, said in the release.¹

The successful use of Darvall’s ventilator with sea lions represents a breakthrough for veterinary medicine and conservation efforts, according to the company. Company officials surmised that further development and validation of this technology could transform the anesthetic care of dolphins, seals, and other diving mammals worldwide.¹

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