Types of Anesthesia

World Anesthesia Day – October 16, 2022

Have you been anesthetized? Do you remember your anesthesiologist? Well, many times we don’t remember the director of the movies, they are there but behind the screens. As you won’t be seeing your anesthetist as an outpatient for follow ups, it’s fair enough that people tend to forget their anesthetic part of the surgery. But times are changing for the better; we do get acknowledged for the safe journey of surgery and the pain free stay at the hospital. Abolishing pain is bliss, it’s an exceptional skill to make a patient comfortable and speed up their recovery. When did anesthesia begin?

In 1846, on October 16th, the successful demonstration of di-ethyl ether gas anesthesia was performed in Massachusetts General Hospital in Boston, where the patient had a pain free procedure done by Dr William T. G. Morton for the first time. This day is celebrated as World Anesthesia Day.

Though it has been more than 170 years since then and many surgical milestones have been accomplished, many of us are still unaware about what ANAESTHESIA is. This article intends to create an outline about the TYPES OF ANAESTHESIA. The goal of an anesthetist is to keep a patient pain free and comfortable and with stable vital parameters which include heart rate, respiratory rate, blood pressure, oxygenation, temperature, glycemic levels and urine output. We have four types of anesthesia.

  • Local Anesthesia:

    Here, the local part of the body is made numb by injecting drugs at the site of surgery or procedure. For example, removal of swelling from a specific plane. This injection is similar to the one you get for a dental extraction. It is most commonly used for draining abscess i.e., local infective collection of fluid, suturing wounds and cleaning of wounds. This needs patient co-operation for not moving. The patient will be awake during the procedure. Also, surgeons give the local injection and we monitor the patient and intervene when there is a need to stabilize the patient.

  • Regional Anesthesia:

    This is done by injecting a needle to administer anesthesia:

    • Spinal Anesthesia:

      This is given by a fine needle injection at your back (lumbar region) to reach the intrathecal space which contains the cerebrospinal fluid. The anesthesia drug enters and abolishes sensation and movement below the umbilicus. Most of the time this will be the anesthesia plan for surgeries below umbilicus.

    • Epidural Anaesthesia & Analgesia:

      Epidural is the space around the spinal cord where the catheter is placed in space. Drug dosage is decided according to the purpose, whether it is for surgery or pain relief. It is commonly used for painless deliveries and major abdominal or lower limb surgeries. It can be combined with spinal or general anesthesia also for postoperative pain management.

    • Nerve Block:

      Anesthesia is achieved by needle injection targeting the nerve bundle and by depositing drug soaking the nerve bundle to achieve anesthesia pertaining to the specific limbs or part. We use ultrasound or nerve stimulators as a guide for locating the nerves. It is most commonly used in orthopaedic and plastic surgery procedures for limb surgeries. It is one of the best as pain relief is for a longer duration, patients can resume oral food, recovery is the fastest with more benefits for elderly and people with chronic medical diseases involving heart, kidney, liver and lung issues.

  • General Anesthesia:

    Everyone thinks this is the best form of anesthesia as you go to sleep just like that with drugs getting inside your intravenous cannula. Actually, it is more than that. For a magical sleep, we need to achieve loss of consciousness + loss of mobility + loss of memory + loss of pain. An oxygen tube is secured which is connected to the ventilator for oxygenation and monitoring lung dynamics. Once the procedure is over, we reverse and wake the patient up from anesthesia. There are a few criteria (i.e., regular breathing with good efforts, spontaneous eye opening on their own, obeying commands and ability to follow simple commands) which patients should fulfill to get reversed and for the oxygen tube kept in to be taken out. It’s true to feel like a pleasant dream journey when you wake up. It is because when you are waking up it will be the same like before when you fell asleep. Hence, people are fond of this euphoric heaven.

  • Intravenous Conscious Sedation:

    In this, we administer intravenous drugs to make them semi-conscious without having an oxygen tube inside the wind pipe (trachea). We administer this form of anesthesia for endoscopy & bronchoscopy procedures, all angiograms, dental extraction, closed reduction to fix fractures, for claustrophobic patients in MRI and to make paediatric & anxious patients comfortable when local anaesthesia is adequate for the procedure. The top up of sedation calms the patients to cooperate for the procedure. Early recovery to hit back the routine is the advantage.

All anesthesia techniques are done under sterile precautions and monitoring – with an electrocardiogram for heart rate, blood pressure, respiratory rate, oxygenation and temperature.

Take Home Message

I would say the injection is going to be the same as the prick for the blood test. Whenever there is an option of local or regional anesthesia, do opt for it as these drugs are safer than general anesthesia drugs. These drugs do not enter the bloodstream to bring hemodynamic changes. With the help of our digital technology advancements, we have achieved the accuracy in monitoring even the depth of anesthesia for a patient to make sure there is no awareness and all parameters are within the normal range. There are surgeries where only general anesthesia is the choice. In that case, we do have to accept and go ahead. To emphasize, getting knocked off is not the only form of anesthesia. When your surgery date is electively fixed, do consult your anesthesiologist to get your evaluation from an anaesthetist’s point of view and investigations and also to know which type of anesthesia you would fit in for. This consultation is mandatory when the surgical procedure is completely planned, not for emergency surgeries.


Dr. K. Mahalakshmi
Consultant Anaesthesiologist
Kauvery Hospital Chennai