Introduction:
Since cocaine is the only naturally occurring local anesthetic, the development of regional anesthesia began with the isolation of local anesthetics. In 1898, August Bier performed the first spinal anesthesia procedure in Germany, making spinal anesthesia the first regional anesthetic treatment ever used. Until this point, topical ocular anesthesia and infiltration anesthesia were the sole methods of local anesthesia. The spinal cord and brain comprise the central nervous system (CNS). Local anesthesia administered within or near the central nervous system is known as neuraxial anesthesia. In spinal anesthesia, a local anesthetic is injected directly into the intrathecal (subarachnoid) region using a neuraxial method. This article goes over the application, indications, and contraindications of spinal anesthetics and emphasizes the role of the interprofessional team in handling these patients.
What Are the Indications and Contraindications of Spinal Anesthesia?
Indications:
-
For the majority of surgeries performed below the neck, neuraxial anesthesia is utilized either alone or in conjunction with general anesthesia. Spinal anesthesia is frequently used for surgical operations that include the pelvis, lower limbs, perineal, and lower abdomen; it is especially useful for treatments that are performed below the umbilicus.
-
Signed informed permission is required, and the patient must receive counseling regarding the surgery. Since the surgery is typically carried out on awake or mildly sedated patients, some of the topics that can help reduce anxiety include the indication for spinal anesthesia, what to anticipate during neuraxial installation, risks, advantages, and alternative procedures. It is imperative to inform patients that until the issue is resolved, their range of motion in their lower extremities is limited.
-
Short operations work best under spinal anesthesia. Generally, general anesthesia is preferred for longer procedures or those that could affect breathing.
Contraindications:
Neuraxial anesthesia (spinal and epidural) has significant known contraindications. The patient's refusal of consent and increased intracranial pressure (ICP), mainly because of an intracranial mass and an infection at the surgery site (posing a risk of meningitis), are the absolute contraindications.
Relative Contraindications
-
Preexisting neurological conditions, especially cyclical ones, such as multiple sclerosis (nerves' protective covering is damaged by the immune system).
-
Severe dehydration (the possibility of hypotension brings on hypovolemia (fluid loss); risk factors for hypotension include age [greater than 40 to 50], obesity, emergency surgery, hypovolemia, and long-term alcohol use.
-
Clotting disorders or thrombocytopenia (blood clot decreases) (particularly when combined with epidural anesthesia because of the possibility of epidural hematoma (blood clot pool).
Additional relative contraindications include left ventricular outflow restriction, as observed in hypertrophic obstructive cardiomyopathy (heart muscle disease), and severe mitral and aortic stenosis(thickening and narrowing of aortic valve). Reevaluating the location of the neuraxial block is necessary when coagulopathy is present. For patients using oral anticoagulants, antiplatelets, thrombolytic treatment, unfractionated, or low molecular weight heparin, the American Society of Regional Anesthesia (ASRA) releases new guidelines that specify whether to undergo neuraxial anesthesia. Before starting the process, go over the most recent instructions. In general, a risk or benefit analysis must be done before moving further because these operations are optional.
Equipment:
-
A sterile environment must be maintained by the doctor since neuraxial procedures must be performed using an aseptic technique. Sterilized gloves, a cap, a mask, and hand washing are needed. Sufficient planning is necessary for a successful outcome. Enough room and equipment should be available to fit patients and staff. The patient's temperature, oxygenation (continuous pulse oximetry), blood pressure, and circulation should all be monitored with monitors ready to go. Monitor use and interpretation need to be second nature to the doctor carrying out the procedure. While planning sedation, measures to support patient ventilation, oxygenation, and circulatory support should be in place. Establishing intravenous access is necessary before beginning. A licensed anesthesiologist must be present if the patient needs general anesthesia.
-
Commercial kits for spinal anesthesia are available. Chlorhexidine with alcohol, drape, and a local penetrating anesthetic (often 1 percent lidocaine) are typically included in kits. The additional contents include the preservative-free spinal anesthetic solution, three mL(milliliters) and five mL syringes, and the spinal needle. Tetracaine, Procaine, Ropivacaine, Bupivacaine, and Lidocaine are a few possible solutions.
What Does Spinal Anesthesia Involve?
The lower back is pricked with a tiny needle to numb the nerves from the waist down with a local anesthetic injection. The spinal typically lasts two to three hours. Depending on the medication the patients take, this could alter. The kind of operation performed and the duration of the procedure determines how much anesthesia patients receive.
One might take more analgesics to aid in the pain alleviation following the procedure.
What Is the Procedure of Spinal Anesthesia?
-
On the day of the procedure, the anesthetist will review this with the patient in advance.
-
Although it can be done in the operating room, the spinal is often performed in an anesthetic room. A little plastic tube, sometimes known as a "cannula" or "drip," will be inserted into a vein, generally in the back of the hand or arm, by an anesthesiologist.
-
The blood pressure, oxygen saturation, and heart rate will all be monitored by the anesthetic assistant using monitoring equipment. The spinal anesthetic will then be administered, and the patient will be put into position. The patient will either be lying on the side with the knees raised to the chest or sitting upright on the side of the bed with the feet resting on a stool.
-
A cold disinfectant will be applied to clean the back. To make the spinal injection more comfortable for the patient, a local anesthetic injection is subsequently administered at the skin.
-
Throughout the injection, a nurse or healthcare assistant will be there to support and reassure the patient, in addition to the anesthetist, who will explain the process as it happens.
-
Performing the treatment typically takes five to ten minutes, but on rare occasions, it may take longer due to specific characteristics that make it more difficult to locate the proper location for the spinal injection.
What Are the Complications of Spinal Anesthesia?
-
Back pain (more prevalent after receiving epidural anesthesia).
-
Post-dural puncture headache (up to 25 percent in some studies): all patients should use the smallest gauge needle available, and non-cutting needles should be used for those who are at high risk of developing post-dural puncture migraines.
-
Vomiting and nausea.
-
Low blood pressure.
-
Hearing loss at low frequencies.
-
Complete spinal anesthesia—the most dangerous side effect.
-
Damage to the nervous system.
-
Hematoma (pool of clotted blood) in the spine.
-
The arachnoid (transient neurological condition, particularly when using lidocaine).
Conclusion:
After ventilation is started and the patient's hemodynamics stabilize, a sedative should be administered. Complete spinal anesthetic normally wears off before the end of the surgery, at which point the patient can be extubated unless there is a contraindication. The research conducted eliminates myths about the viability and safety of pediatric spinal anesthesia thanks to its excellent success rate (96.1 percent) and extremely low complication rates. For daycare procedures, this approach may be favored because of its early motor recovery and lack of danger for respiratory depression and pulmonary aspiration.
