3.6.2 Surgical and anaesthetic techniques to limit blood loss |
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Read through these techniques. Then have a look at the map at the foot of the page and see how they fit into the context of blood conservation.
Hypotensive anaesthesia
Hypotensive means having low blood pressure. Hypotensive anesthesia is a technique that lowers a patient's blood pressure below normal during surgery. Blood loss tends to be slower when blood pressure is low. However, blood pressure must be maintained at a particular threshold to ensure that all the body's organs and tissues are receiving blood, so the practice of hypotensive anesthesia requires great skill and extraordinarily careful monitoring.
Maintenance of normothermia
I.e normal body temperature.
Haemodilution
The process of making blood more dilute than normal. The result is that when a patient bleeds during surgery, the diluted blood contains a lower concentration of red blood cells.
Acute normovolemic haemodilution
All people maintain a particular volume of fluid circulating throughout their bodies; this is referred to as "normovolemia." During surgery, a patient is given balanced intravenous solutions (volume expanders) to replace the fluids, salts, and sugars that are invariably lost during the course of surgery.
Iin this process, blood is removed from the patient and replaced with fluids, maitaining normal fluid volume. This enables a greater degree of haemodilution than hypervolemic haemodilution.
Hypervolemia: abnormal increase in the volume of circulating blood. Haemodilution: an increase in the volume of blood plasma resulting in reduced relative concentration of red blood cells.
In this process, no blood is removed from the patient.
When bleeing occurs under these conditions fewer red blood cells are lost because of its diluted state.
Intra-operative cell salvage
The subject of this online training programme and its associated classroom courses.
Post-operative blood salvage
"Post-operative cell salvage (POCS) involves the collection of blood from
surgical drains followed by reinfusion, with or without a wash cycle. Although
there have been concerns about the safety of transfusing unwashed red cells,
POCS is used routinely in orthopaedic surgery in a number of hospitals in the
country and the NBS is not aware of any serious untoward incidents associated
with its use."
See Blood Matters Issue 11, September 2002 published by the National Blood Service.
Laparoscopic surgery (keyhole surgery)
A surgical technique in which a lighted scope is inserted into a tiny incision in the abdomen. Laparoscopy can be used to visualize the inside of the abdomen for diagnosis, to retrieve tissue samples for biopsy, and to perform surgery using tiny instruments that are also passed into the abdomen through tiny "keyhole" incisions. Laparoscopy is considered a "minimally invasive" procedure, which results in reduced bleeding and may therefore be valuable for bloodless treatment of some conditions.
Reduce blood flow to skin
A technique used in treating the burn patient to reduce blood loss during debridement. Debridement is scraping off the dead skin, exposing the raw tissue underneath. Decreasing blood flow to the surface lessens blood loss during debridement. However, such restricted blood flow cannot be maintained for extended periods of time.
Meticulous haemostasis
Haemostasis means to stop bleeding. When meticulous haemostasis applied to surgical processes, less bleeding occurs.
Arterial embolisation
This refers to various methods of blocking a bleeding blood vessel, preventing further blood loss. These include chemical agents that scar the inside of the blood vessel; mechanical agents that block a bleeding vessel, including metal coils and latex or silicone balloons; particles or microspheres, including gelatin foam; and injected liquid that quickly turns into a thicker gel-like or spongy mass to prevent bleeding from a vessel.
Pre-operative planning
Assessment and Planning before an elective operation ensures a patient is in the best condition for the proposed procedures.
· Enlarged surgical team/Minimal time
This helps reduce the potential for blood loss during surgery.
· Surgical positioning
When an operation site is above the level of the patient's heart, bleeding can often be reduced. Avoiding pressure on major veins also helps reduce blood loss.
· Staging of complex procedures
Helps reduce the potential for blood loss during surgery.
Cryosurgery
A surgical technique that uses extreme cold to destroy abnormal tissues in the body. It is sometimes used as a bloodless medicine technique -- by freezing tissue, bleeding is minimized.
Minimally invasive surgery
Procedures that use small surgical cuts and holes, or no cuts at all. These methods can greatly reduce the amount of bleeding and are therefore of great importance to bloodless medicine.
· Endoscopy
A scope that can be used to visualize the inside of the body, either through insertion into a tiny incision or by passing the scope through a body opening (such as the mouth or anus). Endoscopy is used to examine, biopsy, or surgically treat a variety of conditions. Types of endoscopy include arthroscopy (joints); bronchoscopy (bronchial tubes, lungs); colonoscopy/sigmoidoscopy (large intestine); colposcopy (vagina, cervix); gastroscopy (stomach, small intestine); laparoscopy (abdomen); and others. Endoscopy is considered a "minimally invasive" procedure, which results in reduced bleeding. It is therefore a valuable bloodless medicine technique.
· Lithotripsy
Lithotripsy uses sound waves to break up a kidney or other stone into smaller bits, allowing it to pass out of the urinary system without having created any incision at all.
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