Dr. Emma was frantic. “Help! I’ve excised many masses over the years, but I’ve never seen one bleed like this.”
I could hear her distress over the phone as her patient’s blood pressure dropped. After a little help, the dog eventually did fine, so this is a perfect opportunity to review our options for hemostasis.
Here is a non-exhaustive list of techniques to stop bleeding. We will assume that our patient has normal clotting capabilities.
Time. As the saying goes, “All bleeders stop…eventually.” This law has never failed in the history of mankind or petkind. Not even once. It’s just a matter of time.
That said, we would rather keep bloodletting within reason. Time will allow small vessels to clot on their own.
Direct pressure. A classic mistake is to apply too much pressure, especially under stress. Too much pressure completely occludes the blood vessel, which prevents platelets and clotting factors from reaching the bleeding site, and prevents formation of a fibrin clot.
Appropriate pressure may be all you need if the blood vessels are small enough. How much pressure to apply is an art form, which is acquired with experience. You need just enough compression and time to stop bleeding.
Another classic error is to rub surgical sites with gauze squares, which can dislodge microthrombi from the lumen of blood vessels and cause them to bleed all over again. Therefore, we should gently blot a surgical area, and never rub.
Electrocautery. Electrocautery is one of the most convenient yet underutilized ways to provide hemostasis of small arteries (up to 1 mm in diameter) and veins (up to 2 mm). A little zap, and the lumen of blood vessels is sealed. Alternatives include radiosurgery and lasers.
Hemostatic forceps. Hemostatic forceps work by two complementary mechanisms: they occlude a bleeding blood vessel and damage its wall, both of which stimulate clotting. If the vessel diameter is small enough, the hemostat can be removed safely after a few minutes.
Ligation. Tying vessels is a common technique to stop bleeding. If a hemostat is used to occlude the vessel temporarily, it is important to remember to “flash” the instrument before tightening the suture material. Otherwise, the blood vessel will not be tied correctly, and hemorrhage will start again.
Transfixation. Using a transfixation ligature decreases the risk of slippage. The suture material is passed through the vessel or stump, tied around one half of the stump, then around the entire stump. Ultimately, we have a knot on both sides of the vessel.
Transfixation is commonly used on the uterine stump during a spay, but it can be used to secure ligatures on any large vessel, during amputation or splenectomy for example. This technique was first described by our good friend Halsted (JAMA 1913).*
Vascular clips. Vascular clips are a quick and convenient option. It is important to choose a clip size that is longer (about 1/3 to 2/3) than the diameter of the vessel. It’s a matter of basic physics: Once flattened by the clip, the circular vessel will become oval, and therefore longer.
If you do not take this little fact into consideration, bleeding will continue after application of the clip.
The not-so-negligible cost of vascular clips has to be weighed against the price of suture material, surgeon and anesthesia time saved, as well as the convenience and ease of use.
Hemostatic agents. There are numerous hemostatic agents on the market. They include:
- Bone wax, which is used on cut bone surfaces, e.g. after mandibulectomy and maxillectomy. The wax stops the bleeding mechanically. Since it is poorly absorbed, wax may interfere with healing and could potentiate infection.
- Gelatin foam sponges (Gelfoam, Vetspon), which are reabsorbed in four to six weeks.
- Celox, which comes in various forms. The powdered version is a convenient, sterile hemostatic agent made of the polysaccharide chitosan.
- Topical epinephrine. It causes vasoconstriction, which makes it easier for a blood clot to plug the blood vessel. One common location where topical epinephrine is used is after excision of laryngeal saccules.
Tourniquet. Using a tourniquet is often advised to control bleeding during procedures on the extremities, such as toe amputation. I’m not too fond of the idea, as it can be misleading. Surely, bleeding will be minimized as long as the tourniquet is on, giving you a false sense of security.
But as soon as you are done with your skin sutures and release the tourniquet, hemorrhage might start. If you use a tourniquet, then consider removing it intraoperatively to ensure than there is truly no hemorrhage.
Vascular clips can be used instead of ligatures for a spay.
Again, this is a non-exhaustive list of tips. None is necessarily better than another. As with many other situations in surgery, it’s a matter of indications: the nature of the tissue, the character of the bleeding, the size of the vessel and the resources you have.
There are other, fancier techniques and other very cool toys, but the tips above should help you handle virtually all common situations.
Ultimately, not every single bleeding vessel needs to be stopped. Experience will help determine what is acceptable (a few cutaneous bleeders) and what is unforgiving (a “small” artery after splenectomy). Experience comes at a price, though, which might cost your patient his or her life. Within reason, it is typically better to err on the safe side: rather too much hemostasis than not enough.
Here are six additional suggestions:
Don’t panic. It may be easy to say, but panicking surely won’t help you or your patient. Apply pressure to the bleeding area, take a deep breath, adjust the light, have suction, sponges and hemostats ready, get an assistant if needed, and go over your options calmly.
Cut wisely. Knowing your anatomy and avoiding blood vessels are sure ways to decrease bleeding.
Handle tissues gently and respectfully, as per Halsted’s principles.*
Clamp before you cut. If you must cut a vessel, clamp and possibly ligate both sides before you cut it. This can be called prophylactic hemostasis.
Keep a clean field. Whether you use sponges (don’t be stingy with the number of sponges used!) or suction, removing blood efficiently is critical to being able to isolate the bleeding vessel.
Be proactive if not aggressive with treating blood loss, whether with colloids or blood products.
“All bleeders stop…eventually” is one of these indisputable, unquestionable, infallible laws of veterinary medicine, right along with: “Never perform a rectal exam on an awakened rhino.”
* To learn more about Halsted, please read the September 2010 issue of Veterinary Practice News or click here.