A fluid used to test for leaks in kidney dialysis filters may be behind a recent spate of unexplained deaths, says US dialyser manufacturer Baxter.
Baxter filters have been linked to 23 deaths in Croatia, 10 in Spain, 41 in India, seven in Taiwan, two in Colombia and at least four in the US. The first reports of suspicious deaths were in Spain in August. However, independent tests failed to identify any faults in the Baxter A series dialysers used during or immediately prior to the patients鈥� deaths.
But animal tests conducted on 3 and 4 November suggest that a perfluorohydrocarbon used in a Baxter manufacturing plant in Ronneby, Sweden might have caused fatal air bubbles to form in the patients鈥� hearts.
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Baxter renal researchers found that an injection of just 160 microlitres of the liquid was enough to kill a rabbit. The liquid was thought to be non-toxic. But the team found air embolisms in the right side of the rabbits鈥� hearts. Autopsies on eight of the patients who died in Croatia also found evidence of air embolisms in the hearts.
鈥淭his is just a first cut on some animal studies,鈥� said Baxter鈥檚 Patty O鈥橦ayer. 鈥淲e have not got to the bottom of the deaths in any way, shape or form. But we have found traces of the fluid in the dialysers and it is possible that it may be linked to the deaths.鈥�
Magnifying glass
Baxter issued a worldwide recall of all its A series filters on 19 October as a 鈥減recautionary measure鈥�. It has now stopped all production of the dialysers at its Swedish factory, the source of all the filters linked to suspicious deaths. The factory produced about 10 per cent of Baxter鈥檚 A series of filters but was the only one to use the perfluorohydrocarbon.
As part of the Swedish manufacturing process, the dialysers are immersed in the perfluorohydrocarbon, before air is pumped through. Factory workers use magnifying glasses to look for tiny bubbles that would indicate a leak.
The dialysers are then cleaned. Dialysis nurses are also trained to pump at least one litre of cleansing saline solution through a filter before it is used on a patient.
But Baxter says if traces of the fluid did remain in the dialyser, it is possible it could enter the body and create air bubbles in the blood under certain temperatures and pressures.
The company says all reports of suspicious deaths will be fully investigated. 鈥淲e are seeing an increased number of cases being reported,鈥� says O鈥橦ayer. 鈥淲hether they are linked or not we don鈥檛 know.鈥�