The most common type of anesthesia is General Anesthesia. When a patient undergoes this type of anesthetic the intention is to put the patient completely to sleep but also to make them relax and to feel no pain. It is also important that the patient not have any recall of the circumstances of the procedure. When this occurs the anesthesia provider will use a variety of medications to accomplish all of the above. In the past most anesthetics would start with medications to make you relax and forget the events of your anesthetic. This is why most people would only remember a short converstion with the anesthesia provider and then there next episode of awareness would be when they awakened in the recovery room.
Once the patient is in the room, situated in the bed and all the monitors are on and running they are given oxygen and then what is commonly called an induction agent. Today most adults are given a medication by the name of propofol. In the hands of a certified anesthesia provider it is quite safe. This medication may burn slightly as it is given through the IV and will quickly cause a profound sleep, some relaxation and respiratory depression. In many cases today it is likely an LMA will be inserted in the airway. The LMA is a balloon like device that splints the airway open and allows air to pass in and out of the windpipe. This will be connected to the ventilation circuit of an anesthesia machine and the patient will receive carefully measured amounts of gas anesthetic to keep them asleep. When the case is over this airway will be removed and the patient will awaken in the recovery room
In many other cases due to the requirements of the surgeon it will be necessary to completely relax or paralyze the patient. In this situation it will be necessary to put a small tube past the windpipe and vocal cords directly into the airway. To accomplish this, in addition to the propofol, it will be necessary to also give a medication to relax the patient. These medications are of two types. The first type is succinylcholine that causes the muscles to contract and then stay relaxed for a short time. The second type is what is known as non-depolarizing drugs that cause the muscles to relax but for longer periods of time. Regardless of which is chosen the patients respiration will require assistance by the AP often using a mask and ventilation bag. A small tube is then inserted carefully into the airway using a laryngoscope. This device is a metal or plastic tool with a small light at the end and allows visualization of the airway. This is usually an easy thing to do in the hands of a seasoned AP, but in some cases it can become very difficult. More on this will be available in our Complications Section.
Once the patient is asleep they will continue to receive either gas anesthetic agents through the tube or intravenous medications to keep the patient asleep, somewhat relaxed and to some degree unresponsive to painful stimulation. If given anesthetic drugs in sufficient doses the patient will not likely remember the procedure. Today most APs will monitor the brain wave activity to verify there will be no recall. They will use a device called a BIS monitor that reads the EEG and runs the information through a formula that reliably indicates whether there is any likelihood of recall or not.
Another part of the anesthetic is the relaxation accomplished which is dependent upon the procedure. In the case of abdominal procedures, neurosurgery, and some back procedures it is very important the patient be totally relaxed. This is accomplished partly with the anesthetic drug given to keep the patient to sleep but also with paralyzing agents as those previously mentioned. These drugs will make the muscles unable to contract and will give the surgeon the optimal surgical field for their procedure. At the end of the procedure it is important to discontinue these drugs so that all effects have worn off, otherwise the patient will not be able to breathe. Throughout the case the AP will use a nerve stimulator to monitor the effects of these drugs.
The last aspect to mention is the idea of pain control. It is important that the patient receive good pain control throughout the procedure and upon the end of the case. If a patient does not have good pain control during the case they will tend to develop a high pulse rate and an elevated blood pressure which can make things difficult for the surgeon. At the end of the case the last thing you want to see is a patient waking up with extreme pain. This is one of the aspects of anesthesia that requires often a great deal of experience. In most situations pain killers such as narcotics are administered judiciously to keep this issue under control. The medications are given in such quantities that the patient will not be oversedated at the end and will also have good control of their pain.