Placing tubes, catheters and other medical procedures


Urinalysis Collection

Question: Just a little question, I have a 12 year old German shepherd that I want to get insurance for. To do so, I need to get the urine sample or leave the dog at the vet to get it. I don't want to leave my dog as she would be upset. Is there an easy way to get a urinalysis. How old can it be to be valuable? I need this info by 3/26/02 as her appointment is 3/27/02 at 7:30a.m By the way, I love your emails.

Answer: Sherrie- It takes between a teaspoon and a tablespoon of urine to run a good urinalysis. Sometimes, knowing that only a small amount of urine is necessary makes the task of collecting it seem more reasonable. Also, the urine should be collected in a clean container or gathered off a clean surface but it doesn't need to be a sterile surface for a routine urinalysis. For best results the urine should be less than 2 to 4 hours old or else refrigerated after collection and tested within 24 hours. The fresher the sample is the better but results are usually reliable within these time frames. My clients have come up with lots of inventive ways for collecting urine.

Some that have worked for female dogs:

1) slide a saucer under the dog as she squats to urinate. There is almost always enough retained by a saucer to do a urinalysis and this works for dogs that get very low to the ground.

2) tape a small disposable paper cup to something that will work as a handle to allow the sample to be collected without reaching under the dog with a hand. A dowel rod, ruler or yardstick will all do fine for most dogs. This helps with dogs who quit urinating if they think you are going to touch or grab them. It might take a couple of tries to get a sample this way, so start early in the morning, or even the night before the exam.

3) Keep a dog confined in a small room with a clean nonpermeable floor until she urinates --- although this can be a bad precedent to set.

4) Get a sample container from your vet or find a clean small bottle or even a zip lock bag and just reach under your dog when she is urinating, if she is tolerant of this action, and collect the urine.

Hand washing will be required with this technique but it is often effective. Your vet can obtain a urine sample by cystocentesis, which is the process of withdrawing urine directly from the bladder. If you anticipate using this technique it is best not to let her urinate for a couple of hours prior to the visit and to try to avoid any temptation to urinate on the way into the vet's office. It doesn't take long to get a sample if there is urine in the bladder. Samples taken in this manner can be used for culture (to check for bacteria in the urinary tract) and are usually better for determining if there is blood in the urine when it is in the bladder since it doesn't pass through the urethra and vagina prior to being collected. We have collected a great number (at least a hundred) urine samples in this manner with no complications that I can recall. We have had some dogs that we could not get a sample from, either because the bladder did not contain enough urine or they were not cooperative. The procedure does not seem to be very painful (just the needle stick) and most dogs tolerate it very well.

I hope this helps some. Mike Richards, DVM 3/23/2002

Anesthesia machines - non-rebreathing and rebreathing circuits

Question: Dr. Mike-

I read in my pet's medical record that a non-rebreathing circuit was used when anesthetizing my dog but that in another place in the record a rebreathing circuit was used. What is the difference?



Answer: A rebreathing circuit on an anesthetic machine sort of looks like the old aqualung breathing apparatus that Lloyd Bridges always wore in "Sea Hunt", if you are old enough to remember that show. A large tube carries oxygen mixed with anesthetic gas to the endotracheal tube the pet is breathing through. A second large tube carries the exhaled gas away from the patient, where it goes through a scrubber that removes the carbon dioxide. The cleaned gas is then recycled through the breathing tube and the patient breathes it again. This preserves anesthetic gas and an equilibrium is established with new oxygen flow that keeps the gas levels constant. The problem with this setup is that there is a large volume of gas in the anesthetic tubes at any time and the pet must have adequate lung volume to move the gas through the tube so that it is not breathing gas that has not been cleaned of carbon dioxide.

A non-rebreathing circuit has a much smaller tube that delivers the gas and oxygen mixture to the endotracheal tube the pet is breathing through. Exhaled gas goes into a small tube that runs to an evacuation system or to the outside, so the gas is not recycled. The advantage of this setup is that every breath delivers new oyxgen and new gas to the patient, which ensures that the mixture doesn't contain excessive carbon dioxide or different concentrations of oxygen or anesthetic gas than the desired levels.

In general, non-rebreathing systems are strongly advocated for patients weighing less than 10 lbs. and are a good idea for patients weighing 20 lbs. or less. Patients in this size range may not be able to move enough air to make a rebreathing circuit work properly. Usually, this difference is not going to result in an anesthetic death but it may have been a contributing factor.

Mike Richards, DVM 8/23/2001

How an esophagostomy tube is implanted

Question: Dr. Richards,

What is the direction that an esophagostomy tube is implanted? And can a dog or cat still be able to vomit? What are the pros and cons, the limitations of the use of this type of tube?

Tony A.

Answer: Tony-

This is how an esophagostomy tube is implanted:

A forceps or tube insertion device is passed down the esophagus to about halfway between the angle of the jaw and the point where the neck meets the chest. The tip of the forceps or instrument is turned to the side so that it is visible under the skin of the neck. An incision is made over the tip of the instrument through the skin and the esophagus. The instrument is then used to grasp the tip of the tube and it is pulled out the mouth. The forcep is released. The tube is then passed from the mouth down the esophagus until the tip is located between the area of the heart and the entrance to the stomach. The tube is then sutured in place at the skin as it is now directed through the skin, down the esophagus and towards the stomach. Usually a light bandage is necessary to cover the tube to prevent the pet from damaging it.

One of the disadvantages of esophagostomy tubes is that pets can cause the tube to be regurgitated in some instances. This is not highly common but it is a complication of this technique. This is made up for by the fact that the tubes are less likely to cause serious infection since they can't cause peritonitis, they are easier to manage, pets can be fed sooner when an esophagostomy tube is used vs. a stomach tube and most pets tolerate them better. The only real contraindications to esophagostomy tubes are disorders like megaesophagus or esophageal constrictions that make it inappropriate to put food into the esophagus.

When the tubes are regurgitated it is necessary to remove them and replace them. This can usually be done pretty easily, though.

Mike Richards, DVM 6/23/2001

Last edited 10/17/02


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...