Practical fluid therapy (Proceedings)
The goals of fluid therapy in camelids are similar to those in other species. The mechanics and details are somewhat different. Of the possible routes, oral and intravenous are the major routes used to correct problems of hydration. Subcutaneous, intraperitoneal, and intraosseus administration all have specialty applications, but are not useful or necessary in most situations.
Oral fluids are best administered by tube. I prefer to pass the tube through the mouth, as camelids have very narrow nasal passages. Small bore feeding tubes can be used nasally in crias and left in place. Passing an orogastric tube on an adult camelid can induce struggling and a stress response, so it is important to assess whether the patient can tolerate the procedure, have a plan to perform the procedure quickly and competently, and have a plan to abort the procedure if necessary. Alpacas may be manually restrained, whereas llamas may be better restrained in a llama chute. Sedation may help. My preference is to use intramuscular butorphanol, which has less deleterious effects on airway protective responses or cardiac output than many other sedatives. For a speculum, we use a block of wood with the edges rounded and a hole drilled through the center that the tube can fit through. The block is introduced from the side into the interdental space, then seated onto the molars. The tube is passed through the hole, over the base of the tongue and into the esophagus. Negative pressure when sucking back on the tube, palpating the tube adjacent to the cervical trachea, or hearing fluid bubbles over the abdomen when blowing on the tube confirm correct placement.The camelid may respond by struggling, regurgitating, or going into respiratory distress. Any of these may lead to reassessment of the adequacy or restraint or the safety of the procedure.
Once the tube is in place, we usually think it is safe to administer up to about 3.5% of total body weight in fluids at one time (3.5 L to a 100 kg llama). Administering more may be safe in some situations, but also increases the chances of gastric regurgitation. That amount may be given every few hours, unless gastric distention develops, but we usually try to limit ourselves to 3 tubings a day.
The easiest thing to give by tube is water. In dehydrated camelids that have a tendency towards hypernatremia and hyperchloremia, that may be acceptable, but it is likely that a salt solution with an osmolality similar to plasma will have fewer shock effects on gastric microbes, and may be absorbed better. We generally avoid calf electrolyte powders because of the sugar, and make our own isotonic salt solutions.
Much has been made of the difficulty of catheterization in recent years. In my opinion, there are six identifiable and preventable problems that may inhibit catheterizations: