Defibrillator used on diver who was out of air failed to work as its batteries had expired - inquest
Mr McNally from Bruff, Co Limerick drowned in Cork Harbour
A defibrillator used on a diver who had run out of air while trying to free a tangled line failed to work after its batteries expired just five days earlier.
A Cork coroner's inquest heard that, even if the Automated External Defibrillator (AED) had worked, it would have likely made little difference for John McNally (46).
Mr McNally from Bruff, Co Limerick drowned in Cork Harbour on June 14 2014 after he ran out of air at a depth of 18 metres while trying to free a dive line entangled on a lobster pot cable.
The club diver had kind-heartedly offered to free the line and undertake his third dive of the day.
However, the exertion of trying to free the line at depth used up his air faster than anticipated.
He desperately swam 10 metres up towards the surface in just 10 seconds when he realised the problem - an ascent rate six times faster than recommended.
As a result, he suffered from barotrauma or the bends (nitrogen gas compression in the tissues) which was a contributory factor in his death.
Mr McNally was later found by a fellow diver in a kneeling position on the seabed with his air regulator out of his mouth.
Assistant State Pathologist Dr Margaret Bolster said that, even if the AED had worked, it probably wouldn't have saved Mr McNally's life such was the length of time he spent at depth on the seabed.
However, Coroner Dr Myra Cullinane issued a recommendation that divers carefully observe safety guidelines and that they exercise extreme care in unplanned circumstances.
The inquest jury returned a verdict of death by misadventure.
The AED in question was checked just 10 days before the tragedy - but its batteries expired five days before Mr McNally's accident.
Dr Joan Gilvarry of the Health Products Regulatory Authority (HPRA) conducted an independent assessment of the unit.
“The batteries failed four years and two days into their existence when they were needed four years and seven days for a patient.”
The HPRA said the incident was exceptionally rare with only five comparable cases having occurred worldwide despite over 500,000 AEDs being in service.
Mr McNally was one of 17 divers from Cork and Limerick taking part in club exercises that day in Cork Harbour.
He dived on the World War I German U-boat UC-42 before undertaking a second dive near Roches Point on the wreck 'Star Immaculate'.
However, when it was realised that a dive line was snagged, he offered to free it and undertake his third dive of the day.
UK dive safety expert Nick Bailey said data from Mr McNally’s dive computer revealed he undertook a rapid ascent while still wearing his dive weight belt.
He rose 10 metres in just 10 seconds - six times faster than the safe recommended ascent rate.
After briefly pausing, Mr McNally suddenly drifted back down to the seabed where he was later found.
After he was recovered, Mr McNally was rushed to Cork University Hospital (CUH) where he was later pronounced dead.
His dive gear was recovered from the seabed the following day and his air tanks were found to be empty.