Anaesthetic, blood and pain relief

Meeting your anaesthetist

Your anaesthetist is a doctor who specialises in keeping you safe and comfortable through surgery. They will see you beforehand, review your heart, lungs, medicines and previous anaesthetics, and agree a plan with you. This is a genuine discussion — if you have a strong preference, or a bad memory of a previous anaesthetic, say so.

Spinal anaesthetic

For hip replacement, a spinal anaesthetic is the most common choice, particularly for older patients. A very fine needle is used to place local anaesthetic into the fluid around the nerves in your lower back, numbing you from the waist down for a few hours.

You will be asked to sit or lie curled up while it is done. It takes a few minutes.

• Sensation. Local anaesthetic in the skin stings briefly, then there is usually pressure rather than pain. Your legs will begin to feel warm and heavy.
• Awareness. You are awake but almost always given sedation, so most people doze through the whole thing and remember very little. You should not feel the operation, though you may be aware of pushing or vibration.
• Advantages. Less sickness, less drowsiness, less confusion afterwards, less blood loss, no breathing tube, and pain relief that continues for hours after surgery. For frailer older patients this often means a noticeably smoother first day.
• Wearing off. Feeling returns over two to four hours, starting with pins and needles. You may not be able to pass urine until it wears off, so a catheter is occasionally needed.
• Risks. A drop in blood pressure is common and easily treated. Headache afterwards affects roughly 1 in 100. Serious nerve damage is very rare — of the order of 1 in 20,000 to 1 in 50,000.

General anaesthetic

A general anaesthetic — being fully asleep — is used when a spinal is not suitable or not wanted, for example if you take blood thinners that cannot be stopped, have had certain spinal surgery, or simply prefer to be asleep. Anaesthetic is given into a drip in your hand and you drift off within seconds. A tube supports your breathing while you sleep, and you wake in recovery.

It is very safe, but in older patients it carries a somewhat higher chance of sickness, drowsiness and temporary confusion. Sometimes the two techniques are combined.

Nerve blocks and wound infiltration

Whichever main anaesthetic you have, extra local anaesthetic is usually added to reduce pain afterwards:

• Nerve blocks — local anaesthetic placed near specific nerves in the thigh or groin, guided by ultrasound, numbing that area for several hours. Blocks used for hips are chosen carefully so they do not make your leg too weak to stand on, since getting you walking early matters.
• Wound infiltration — the surgeon injects a large volume of dilute local anaesthetic into the tissues around the joint before closing. It is simple, safe and very effective for the first day.

When a block wears off, pain can arrive quite suddenly. Take your regular painkillers before that happens rather than waiting.

Blood loss and transfusion

Hip replacement involves cutting bone, so some bleeding is unavoidable — but far less than in the past.

• Tranexamic acid is now given routinely. It helps blood clot more effectively at the wound and significantly reduces both blood loss and the need for transfusion.
• Spinal anaesthesia and controlled blood pressure reduce bleeding further.
• Treating anaemia beforehand with iron is one of the most effective steps of all, which is why your blood count is checked weeks in advance.

As a result, most people having a planned hip replacement do not need a transfusion. If your blood count does fall far enough to affect you, donated blood is given through a drip. It is carefully matched and tested, and the risks in the UK are extremely small. Your blood count will be checked the day after surgery.

Pain relief after surgery

Expect discomfort, aching and stiffness — but not agony. Good pain control is not a luxury: it is what allows you to breathe deeply, sleep, and get up and walk, all of which prevent complications.

Pain relief is built in layers, starting with the gentlest:

1. Paracetamol, regularly. Taken to the clock, four times a day, it is the foundation of everything else. Do not skip it because you feel reasonably comfortable.
2. Anti-inflammatory drugs such as ibuprofen or naproxen, if your kidneys, stomach and heart allow. Many older patients cannot take these, and that is fine.
3. Weaker opioids such as codeine, or short courses of stronger ones such as oramorph or oxycodone for the first few days.
4. Local anaesthetic from your block or wound infiltration, already working in the background.

Opioids in older people — used, but carefully

Morphine-type drugs are effective and you should have them if you need them. But in older adults they more readily cause drowsiness, confusion, nausea and — almost invariably — constipation. So the aim is the smallest dose for the shortest time, with a laxative started at the same time rather than waiting for a problem. Take your laxative and drink plenty of fluids; constipation after hip surgery is genuinely miserable and entirely preventable.

Non-drug measures that really help

• An ice pack wrapped in a towel, 15 to 20 minutes at a time, for swelling and ache.
• Pillows to support the leg in a comfortable position — your therapist will show you.
• Changing position often, and moving gently rather than staying rigid.
• Taking painkillers 30 to 60 minutes before physiotherapy.

Telling the team about your pain

Staff will ask you to score your pain out of 10, or to describe it as none, mild, moderate or severe. Answer honestly. Underplaying it does not help you, and it is far easier to stay on top of pain than to catch up with it. Tell someone straight away if the pain suddenly becomes much worse, is a new sharp pain, or comes with fever, calf pain or chest pain.

Preventing blood clots

Alongside pain relief, you will be given clot prevention: compression stockings, calf pumps, early walking, and blood-thinning medication — usually tablets or small injections — for a few weeks after you go home. If you are prescribed injections, a nurse will teach you or a family member how to give them, or arrange a district nurse.