What is anaesthesia ?
The tissues are lined with nerves, or small fibres, which transmit pain and sensitivity (figure 1). The nerves also control muscle contraction and enable the movement of each part of the body (figure 2). During surgery, the manipulation of the tissues is felt as an aggression and so the tissues send pain signals to the brain along the nerves (figure 3). Anaesthesia includes all techniques that block the transmission of the pain signals to the brain (figure 4). It also enables the muscles to relax and therefore contributes to providing the best conditions for the surgical procedure. According to the nature of the operation, general or regional anaesthesia is proposed. In the case of general anaesthesia, you are unconscious. In the case of regional anaesthesia, only the part undergoing the operation is anaesthetised and you remain conscious.
Why a anaesthesia consultation ?
Your state of health requires an operation. The anaesthetic will enable a painless operation as well as post-operative pain management.
If you are going to undergo an operation, a pre-anaesthesia consultation is compulsory beforehand.
During the consultation, the anaesthesiologist will discuss with you the best type of anaesthesia for you, according to the operation you will be undergoing, any health problems you may have, your medication and your desires.
How is the anaesthetic administered ?
Whichever type of anaesthesia is used, you will need to fast, that is, not eat, drink or smoke anything from midnight the day before the operation!
An anaesthesiologist will administer the anaesthetic in an operating theatre with all the equipment necessary to guarantee your safety.
You will be prepared and your anaesthesiologist will come and see you to discuss with you again the technique you chose together during the consultation.
He will fit a drip and put sensors on your skin. This will enable him to check the efficacy of the anaesthetic and monitor you throughout the operation.
In the case of a general anaesthetic :
all the drugs are injected, plunging you into a deep sleep. Oxygen will be provided through a mask or a tube if necessary (figure 5). The doctor can thus control your level of unconsciousness, your blood pressure and the relaxation of your muscles. You will not feel or remember a thing.
Anaesthesia is maintained throughout the operation, and you are monitored constantly. Once the operation completed, you will wake up and post-operative pain management will be initiated.
In the case of a regional anaesthetic :
Only the part of the body being operated on is anaesthetised. There are different types of regional anaesthetic :
– Anaesthesia using nerve blocks
Only a single limb, upper or lower, is anaesthetised.
– An anaesthetic drug is injected directly near the nerves responsible for the sensitivity of the limb in question.
– In order to determine the exact location to anaesthetise the nerves, a neurostimulator, which detects electrical activity, is used. A small, flexible needle connected to this device is accurately placed near the nerves. Once the right location is found, the anaesthetic is injected and the limb anaesthetised (figures 6, 7 and 8).
– A small, flexible sheath is left in place to continue injecting the product during the procedure and afterwards to manage the post-operative pain. In general, the nurse removes this sheath on the second day.
– In addition to being an anaesthetic technique, it is also an important way of managing the post-operative pain.
– Epidural anaesthesia
This is the anaesthetic used for childbirth. It anaesthetises both legs and is only indicated for surgery of the lower limbs.
An injection is administered in the lower back near the spinal canal to numb the nerves to the legs. Here, the spinal cord is much higher and therefore further away from the injection site (figure 9).
The anaesthetising product is thus injected in contact with the nerves. This completely numbs both your legs and so any orthopaedic procedure can be carried out.
Your legs will remain anaesthetised for a few hours after the operation; this will also help manage the post-operative pain.
Sometimes, regional techniques are not very effective. A general anaesthetic may then be necessary during the operation.
All these techniques are often combined to provide the greatest comfort during and after the operation.
Post-operative wake-up and return to activities
Whichever type of anaesthesia is used, you will stay in the recovery room for between 30 minutes and several hours according to the procedure and the anaesthetic, but also your age and your state of health. There we can keep an eye on you after the operation and control the pain.
You will then return to your room, where a nurse will be waiting to check on you as well. The pain will continue to be managed according to the guidelines of the anaesthesiologist.
In the case of regional anaesthesia, you will gradually recover the sensitivity and motor function of the part of your body that was anaesthetised.
The nurse will bring you a little snack with the approval of your anaesthesiologist.
Your anaesthesiologist will come and see you at the end of the day to check that everything is fine, regulate the pain and your regular medication if you take any.
He will then come and visit you every day throughout your stay in hospital. He will administer medical care or get specialist advice if necessary.
What are the risks and complications?
Your anaesthesiologist will discuss with you the potential risks and complications linked to the anaesthetic for your operation during the pre-anaesthesia consultation.
What is the expected outcome of the operation ?
People who are to undergo surgery are often worried about the anaesthetic, sometimes more than for the operation itself.
Over the past 20 years, there has been a major revolution in the anaesthetic techniques available, with the advent of regional techniques in particular, which are well suited to orthopaedic surgery.
In addition, they have enabled much better management of post-operative pain necessary for faster, optimal recovery after your operation. Therefore, it is not surprising that they represent over 90 % of the anaesthetics administered to our patients.