ommay resevoir causing violent sickness

HI just wondering if anyone has experienced a voilent reaction when the chemo is put through the ommay resevoir. The docs. have tried so many anti-sickness now and all fail the only one that works is one that puts me to sleep, but even at that I can wake up with in 2hrs and still want to vomit. I end up asleep for about 14 hours and in the hospital for the night. Has anybody any theories or suggestions. Many thanks.