Hello, I'm Dr. Zoe. Hiccups are a rather mysterious problem in rabbits. The few cases I have researched were often associated with an event of GI stasis. There is suspicion the phrenic nerve which enervates the diaphragm becomes inflamed. HOwever, in no case has it been life threatening, although the hiccups can last several days. If it lasts beyond 4 days I really recommend abdominal radiographs with review of these films by a board certified radiologist.

There has not been any association between IV or SQ fluids and hiccups. This doesn't have to do with the lungs primarily. It has to do with a spasm of the diaphragm, which is the thin membrane that separates the chest cavity from the abdomen. As far as how to stop them, I'm not aware of anything you can do other than perhaps apply some positive pressure to the diaphragm for a few seconds. But in these cases even this may not stop the hiccups. As long as the little guy can eat/drink then he should be okay. What concerns me more about your rabbit is the gas distension and hard stomach, likely secondary to the gas. Hopefully, your vet put him on medication to help with the pain and gas. If not, you need to get him on this becuase this is a painful issue. The syringe feeding is excellent and I'm glad to hear he started eating again.