system
Given the following post, respond as if you're commenting on Reddit:
human
Why do people appear to not be bleeding in images/videos of surgeries in progress?

Pictures/videos of surgeries always have no blood anywhere, and a gaping wound...they might wipe every now and then, but for the most part, there is no blood.
Is it all anti-anticoagulants? 
Do they clamp off all the capillaries? Am I answering my own question?
Why do folks need multiple transfusions then? (during/after surgery)
gpt
While it depends on the type, surgeries do tend to bleed a lot. Superficially there may not seem to be much bleeding, however a large amount of blood may have been suctioned away or hidden, collecting at the bottom of a cavity (e.g. abdominal surgery). However, unless there is truly significant blood loss, there is a tendency towards replacing fluid rather than using blood transfusions.

There are several methods used to reduce blood loss. Most of the surgeries I've seen used a diathermy (rather than a scalpel) - It's a device that uses an electrical current to cut and cauterise tissue, closing the smaller blood vessels/capillaries and preventing excessive bleeding. Laser surgery presumably achieves a similar thing. 

For larger blood vessels, the surgeons can throw a few stitches (a ligature) to tie off the blood vessel, or close the vessel with a clip. Prior to tying/clipping the vessel, haemostats might be used to clamp close the vessel. For orthopaedic/limb surgery, a tourniquet can be used to completely occlude blood supply to that limb (which presents risks of ischaemia/damage).

Positioning the patient in a certain way can also reduce bleeding (e.g. a downwards slope with the head and chest lower than the abdomen and legs).

In terms of pharmaceuticals, the anaesthetist can use drugs to maintain a lower blood pressure to reduce bleeding. In scenarios with a high risk of blood loss, drugs can be used reduce bleeding (i.e. antifibrinolytics and coagulants). However, for the most part, patients are often given drugs to *decrease* coagulation. While excessive bleeding is undesirable, surgery also carries the risk of deep vein thrombosis and pulmonary embolisms - so anticoagulation/DVT prophylaxis is usually preferable.