Haemostatic Techniques
The important Haemostatic Techniques used to control local Haemorrhage include; application of pressure, instruments, ligatures; thermal cauterisation and haemostatic agents to aid coagulation.
1. Digital Pressure
Pressure applied to a vessel proximal to the bleeding site by the fingers of an assistant. The digital compression is less traumatic to the intima of the vessel wall, than instruments.
2. Forcipressure
Forcipressure consists of applying an Artery forceps (Haemostatic forceps) to the bleeding end of the vessel and leaving it in position, until it is convenient to apply a ligature. Haemostatic forceps allow more precise compression of haemorrhaging vessels and are available in various lengths, shapes, and types. They are; Halstead mosquito forceps, Kelly forceps, Crile forceps, Oschner forceps, Carmelt forceps.
When a vessel is crushed, the endothelial and muscular coats of the vessel rupture first and they retract slightly into the lumen of the vessel and the tough areolar coat forms a cap over this. A clot is soon formed inside the vessel, adjoining the ruptured ends of the coats.
Basic principles for application of haemostatic forceps are–
- The smallest forceps capable of accomplishing hemostasis should be used.
- Curved haemostats facilitate improved visibility and preferred to straight haemostats.
- For occluding a small superficial bleeder, the tip of the haemostat is used to grasp the smallest amount of tissue possible, preferably only the bleeding vessel itself.
- When surgical assistant is not available and haemostats are applied in succession, time can be saved, by carrying multiple haemostats with the third finger and palm
- For occluding deep bleeders and vascular pedicles; the haemostatic forceps are applied with the concave surface of the tip facing the transected end of the vessel to facilitate ligation.
- Larger pedicles are clamped with Carmalt forceps to reduce slippage or laceration of the pedicle.
3. Ligation
Ligation is the use of suture materials and surgical knots to occlude the blood vessels. It is a haemostatic method most commonly used. For larger vessels, definitive haemostasis and increased security provided by ligatures, compensates time spent on application.
As a rule ligatures are tied with square knots, which are the least likely to loosen or untie.
Surgeon’s knot can be used with advantage for ligation of vascular pedicles with synthetic sutures.
A surgeon’s knot is not recommended when using surgical gut, because increased friction tends to weaken it at the knot.
The increased bulk and asymmetry of the surgeon’s knot make less suitable for general ligation than the square knot.
Double ligatures are recommended for large isolated vessels, especially arteries.
For large pulsating arteries transfixation ligatures are used.
4. Ligating clips
Ligating clips are ‘V’ shaped stainless steel clips widely used to control bleeding during surgery. They have minimal reactivity in tissues and often offer, improved efficiency compared to ligation.
Advantages of Ligating clips-
- Ease of application in areas of difficult accessibility.
- High strength
- Structural stability
- Improved security
The metallic vascular clips can be easily applied to vessels, using an applicator similar to needle holder. Disadvantage of metal vascular clip, is they persist in the wound as foreign material, which interferes with subsequent radiographic studies.
5. Pressure Pad Haemostasis
Pressure Pad Haemostasis is compressing the haemorrhaging site with gauze sponges and it controls low pressure bleeding from multiple small vessels. Tissues should be gently blotted or mopped with the pressure pads rather than wiped; wiping abrades tissues and dislodges blood clots that were formed. Use of pressure pad haemostasis on larger vessels is temporary. Once the bleeding has been controlled in this fashion, the offending vessels may be identified and ligation may be applied.
6. Pressure Bandages
Pressure Bandages are the most common type of bandages used to hold the soft tissues together. They function to control haemorrhage, prevent edema, obliterate dead space and prevent excessive granulation tissue. Inadvertent vascular and peripheral nerve pressure should be avoided. The pressure generated must be distributed evenly across the bandage surface. A patient’s intolerance is often the first sign of significant problem. When bandages are used to prevent haemorrhage, they should be left in place for a relatively short time of 12 to 24 hours only.
7. Tourniquet
Tourniquet is a cord tied around an extremity (like limb and tail) so as to control bleeding. Diffuse bleeding from multiple vessels is best controlled by placing a tourniquet. It should not be applied very tightly because it may completely arrest blood supply to the part and cause tissue damage. It should not be kept continuously for more than 15 minutes.
8. Esmarch’s Bandage
Esmarch’s Bandage is an elastic bandage applied completely covering, from the distal part of an extremity up to a point above the site of operation, so as to compress the vessels and drive blood from the area into the body.
A tourniquet is then applied, close to the upper limit of the bandage, to prevent return of blood and then the bandage is removed. The tourniquet is removed after the surgery is completed. This method is employed, while doing surgery on limb or tail so as to minimize bleeding during the course of surgery.
9. Crushing
Crushing can be practiced for haemostasis in larger structures like spermatic cord using Emasculator / Ecraseur.
10. Torsion
Torsion is securing the bleeding end of the vessel with an artery forceps and drawing out slightly and twisting on its long axis several times for occluding it. It is sufficient to arrest haemorrhage from small vessels.
11. Tearing
Tearing of tissues often practiced in the removal of tumors (mammary tumors) loosely attached and situated in the vicinity of vessels. This minimize bleeding.
12. Blunt Dissection
It is performed by rupturing the tissues by pressure of blunt instruments. This method is employed for isolation of large vessels like jugular vein and carotid artery.
13. Electrocautery
It may be used to control haemorrhage from arteries up to 1.0mm and up to 2.0mm in diameter. Electrocautery achieves haemostasis through heat induced protein denaturation and tissue coagulation. The basic Electrosurgical instrumentation unit may have either monopolar mode or bipolar mode and a patient ground plate. With either method, tissue trauma is minimized by using the lowest amplitude setting and short duration of application.
14. Electroscalpal
Electroscalpal is an attachment to the electrosurgical unit and is used to make electro-incision or to coagulate small vessels. The surgeon should hold the Electroscalpal perpendicular to the tissue and minimize the contact area at the point of incision.
15. Heated Filaments
Battery powered heated filaments effectively coagulates, blood vessels in ophthalmic surgery.
16. Cryoprobes
Cryoprobes applied at a temperature of -20o C or below, cause cryogenic necrosis of capillaries and venules and controls bleeding.
17. LASER:
The acronym LASER stands for Light Amplification by the Stimulated Emission of Radiation. Lasers may be used to control haemorrhage. Laser energy ruptures RBCs, damages platelets and activates clotting cascades with thrombus formation. Haemostasis is achieved by laser induced endothelial damage, protein denaturation and edema.
18. Topical Haemostatic Agents
- Gelatin sponge
- Oxidized cellulose
- Microfibrillar collagen
- Fibrin glue
- Absorbable collagen
- Cyanoacrylate tissue adhesive
Topical Haemostatic Agents are used to enhance normal clotting. These can be applied topically to control diffuse haemorrhage that is not amenable to other haemostatic methods.
19. Silver Nitrate
Silver Nitrate Chemical agents like silver nitrate have an astringent action on tissues are capable of producing haemostasis.
20. Adrenalin
Hypodermic injection of adrenalin is capable of preventing capillary haemorrhage.
21. Vitamin K
Injection of vitamin-K in doses of 0.5 to 1.0ml for dogs and 10 to 20ml in cattle also helps haemostasis.
22. Calcium
Injection Calcium borogluconate and Calcium gluconate has effect in bringing about coagulation of blood.
23. Other methods
The other means of controlling diffuse haemorrhages are-
- Umbilical tape packing in the nasal cavity bleeding
- Gauze tampons in the vaginal region
- Wound closure techniques