Risks of general, local, epidural and spinal anesthesia

Anesthesia is a strategy used to prevent pain or any sensation during a surgery or painful procedure through the administration of medications through the vein or through inhalation. Anesthesia is usually performed in more invasive procedures or that may cause any discomfort or pain in the patient, such as heart surgery, childbirth or dental procedures, for example.

There are several types of anesthesia, which affect the nervous system in various ways by blocking nerve impulses, the choice of which will depend on the type of medical procedure and the person's health status. It is important that the physician is informed of any type of chronic illness or allergy so that the best type of anesthesia is indicated without any risk. See what is the care before surgery.

1. General anesthesia

During general anesthesia, anesthetic medications are administered that deeply sedate the person, so that the surgery performed, such as heart, lung or abdominal surgery, does not cause any pain or discomfort.

The drugs used make the person unconscious and cause insensitivity to pain, promoting muscle relaxation and causing amnesia, so that everything that happens during surgery is forgotten by the patient.

The anesthetic can be injected into the vein, having an immediate effect, or inhaled through a gas mask, reaching the bloodstream through the lungs. The duration of its effect is variable, being determined by the anesthetist, who decides the quantity of the anesthetic drug to be administered. Learn more about general anesthesia.

The drugs most used in general anesthesia are: benzodiazepines, narcotics, sedatives and hypnotics, muscle relaxants and halogenated gases.

What are the risks

Although anesthesia is a very safe procedure, it may have some associated risks depending on some factors, such as the type of surgery and the person's medical condition. The most common side effects are nausea, vomiting, headache and allergies to the anesthetic medication.

In more severe cases, complications such as breathlessness, cardiac arrest or even neurological sequelae may occur in people with poorer health due to malnutrition, heart, lung or kidney problems, for example.

Although it is very rare, anesthesia may have a partial effect, such as withdrawing consciousness but allowing the person to move or the person not being able to move but feeling the events around them.

2. Local anesthesia

Local anesthesia involves a very specific area of ​​the body, does not affect consciousness and is usually used in minor surgeries such as dental procedures, eye, nose or throat surgery, or in conjunction with other anesthesia, such as regional or sedation anesthesia.

This type of anesthesia can be administered in two ways, by applying an anesthetic cream or spray to a small region of the skin or mucosa, or by injecting the anesthetic medication into the tissue to be anesthetized. Lidocaine is the most common local anesthetic.

What are the risks

Local anesthesia, when used correctly, is safe and has almost no side effects, however, in high doses it can have toxic effects, affecting the heart and breathing or compromising brain function, since high doses can reach the bloodstream.

3. Regional anesthesia

Regional anesthesia is used when it is necessary to anesthetize only a part of the body, such as an arm or leg, for example and there are several types of regional anesthesia:

• Spinal anesthesia

In spinal anesthesia, the local anesthetic is administered with a fine needle, in the fluid that bathes the spinal cord, called cerebrospinal fluid. In this type of anesthesia, the anesthetic mixes with the spinal fluid and contacts the nerves, leading to loss of sensation in the lower limbs and the lower abdomen.

• Epidural anesthesia

Also known as epidural anesthesia, this procedure blocks pain and sensations from only one region of the body, usually from the waist down.

In this type of anesthesia, the local anesthetic is administered through a catheter that is placed in the epidural space that is around the spinal canal, leading to loss of sensation in the lower limbs and abdomen. See more about epidural anesthesia and what it is for.

• Peripheral nerve block

In this type of regional anesthesia, the local anesthetic is administered around the nerves responsible for the sensitivity and movement of the limb where the surgery will be performed, and a variety of nerve blockers can be administered.

The groups of nerves, called the plexus or ganglion, which cause pain to a specific organ or body region, are then blocked leading to anesthesia of areas of the body such as the face, nose, palate, neck, shoulder, arm, among others.

• Regional intravenous anesthesia

Intravenous anesthesia is a procedure in which a catheter is placed in a vein of a limb, so that the local anesthetic is administered, while placing a tourniquet above the area so that the anesthesia remains in place. Sensitivity is restored when the tourniquet is removed.

Regional anesthesia is usually used during simple surgical procedures such as during a normal delivery, in small surgeries such as gynecological or aesthetic surgeries or in orthopedics, for example.

Find out how anesthesia eliminates labor pains.

What are the risks

Although rare, side effects such as excessive sweating, infection at the injection site, systemic toxicity, heart and lung problems, chills, fever, nerve damage, perforation of the membrane that protects the spinal cord, called the dura mater, can occur. cause paraplegia.

Perforation of the dura mater can also trigger post-spinal anesthesia headache in the first 24 hours or up to 5 days later. In such cases, the person feels a headache when sitting or standing and that improves a few minutes after going back to bed, which may be associated with other symptoms such as nausea, stiff neck and decreased hearing. In a good part of the cases this headache disappears spontaneously within a week, but it may also be necessary to start specific treatment indicated by the anesthesiologist.

4. Sedation anesthesia

Sedation anesthesia is administered intravenously and is generally used in combination with regional or local anesthesia in order to increase the person's comfort.

Sedation can be mild, in which the person is relaxed but awake, being able to answer questions from the doctor, moderate in which the person normally sleeps during the procedure, but can be easily woken when asking a question or deep in which the person sleeps throughout the procedure, not remembering what happened since the anesthesia was administered. Whether mild, moderate or deep, this type of anesthesia is accompanied by oxygen supplementation.

What are the risks

Although they are rare, allergic reactions, breathing difficulties, changes in heart rate, nausea, vomiting, delirium, sweating and infection at the injection site can occur.