Anesthesia or anaesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia, paralysis, amnesia, and unconsciousness. An individual under the effects of anesthetic drugs is referred to as being anesthetized.
A local anesthetic (LA) is a medication that causes absence of all sensation in a specific body part without loss of consciousness, as opposed to a general anesthetic, which eliminates all sensation in the entire body and causes unconsciousness. Local anesthetics are most commonly used to eliminate pain during or after surgery. When it is used on specific nerve pathways, paralysis also can be induced.
Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to help diagnose diseases of the central nervous system, including the brain and spine. Examples of these conditions include meningitis and subarachnoid hemorrhage. It may also be used therapeutically in some conditions. Increased intracranial pressure is a contraindication, due to risk of brain matter being compressed and pushed toward the spine. Sometimes, lumbar puncture cannot be performed safely. It is regarded as a safe procedure, but post-dural-puncture headache is a common side effect if a small atraumatic needle is not used.
General anaesthesia (UK) or general anesthesia (US) is a method of medically inducing loss of consciousness that renders a patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general anaesthetic medications, which often act in combination with an analgesic and neuromuscular blocking agent. Spontaneous ventilation is often inadequate during the procedure and intervention is often necessary to protect the airway. General anaesthesia is generally performed in an operating theater to allow surgical procedures that would otherwise be intolerably painful for a patient, or in an intensive care unit or emergency department to facilitate endotracheal intubation and mechanical ventilation in critically ill patients. Depending on the procedure, general anaesthesia may be optional or required. Regardless of whether a patient may prefer to be unconscious or not, certain pain stimuli could result in involuntary responses from the patient that may make an operation extremely difficult. Thus, for many procedures, general anaesthesia is required from a practical perspective.
Combined spinal and epidural anaesthesia is a regional anaesthetic technique, which combines the benefits of both spinal anaesthesia and epidural anaesthesia and analgesia. The spinal component gives a rapid onset of a predictable block. The indwelling epidural catheter gives the ability to provide long lasting analgesia and to titrate the dose given to the desired effect.
An anesthetic or anaesthetic is a drug used to induce anesthesia — in other words, to result in a temporary loss of sensation or awareness. They may be divided into two broad classes: general anesthetics, which result in a reversible loss of consciousness, and local anesthetics, which cause a reversible loss of sensation for a limited region of the body without necessarily affecting consciousness.
Epidural administration is a method of medication administration in which a medicine is injected into the epidural space around the spinal cord. The epidural route is used by physicians and nurse anesthetists to administer local anesthetic agents, analgesics, diagnostic medicines such as radiocontrast agents, and other medicines such as glucocorticoids. Epidural administration involves the placement of a catheter into the epidural space, which may remain in place for the duration of the treatment. The technique of intentional epidural administration of medication was first described in 1921 by Spanish military surgeon Fidel Pagés.
Intrathecal administration is a route of administration for drugs via an injection into the spinal canal, or into the subarachnoid space so that it reaches the cerebrospinal fluid (CSF) and is useful in spinal anesthesia, chemotherapy, or pain management applications. This route is also used to introduce drugs that fight certain infections, particularly post-neurosurgical. The drug needs to be given this way to avoid being stopped by the blood–brain barrier. The same drug given orally must enter the blood stream and may not be able to pass out and into the brain. Drugs given by the intrathecal route often have to be compounded specially by a pharmacist or technician because they cannot contain any preservative or other potentially harmful inactive ingredients that are sometimes found in standard injectable drug preparations.
Bupivacaine, marketed under the brand name Marcaine among others, is a medication used to decrease feeling in a specific area. In nerve blocks, it is injected around a nerve that supplies the area, or into the spinal canal's epidural space. It is available mixed with a small amount of epinephrine to increase the duration of its action. It typically begins working within 15 minutes and lasts for 2 to 8 hours.
Nerve block or regional nerve blockade is any deliberate interruption of signals traveling along a nerve, often for the purpose of pain relief. Local anesthetic nerve block is a short-term block, usually lasting hours or days, involving the injection of an anesthetic, a corticosteroid, and other agents onto or near a nerve. Neurolytic block, the deliberate temporary degeneration of nerve fibers through the application of chemicals, heat, or freezing, produces a block that may persist for weeks, months, or indefinitely. Neurectomy, the cutting through or removal of a nerve or a section of a nerve, usually produces a permanent block. Because neurectomy of a sensory nerve is often followed, months later, by the emergence of new, more intense pain, sensory nerve neurectomy is rarely performed.
Chloroprocaine is a local anesthetic given by injection during surgical procedures and labor and delivery. Chloroprocaine vasodilates; this is in contrast to cocaine which vasoconstricts. Chloroprocaine is an ester anesthetic.
Levobupivacaine (rINN) is a local anaesthetic drug indicated for minor and major surgical anaesthesia and pain management. It is a long-acting amide-type local anaesthetic that blocks nerve impulses by inhibiting sodium ion influx into the nerve cells. Levobupivacaine is the S-enantiomer of racemic bupivacaine and therefore similar in pharmacological effects. The drug typically starts taking effect within 15 minutes and can last up to 16 hours depending on factors such as site of administration and dosage.
Veterinary anesthesia is a specialization in the veterinary medicine field dedicated to the proper administration of anesthetic agents to non-human animals to control their consciousness during procedures. A veterinarian or a Registered Veterinary Technician administers these drugs to minimize stress, destructive behavior, and the threat of injury to both the patient and the doctor. The duration of the anesthesia process goes from the time before an animal leaves for the visit to the time after the animal reaches home after the visit, meaning it includes care from both the owner and the veterinary staff. Generally, anesthesia is used for a wider range of circumstances in animals than in people not only due to their inability to cooperate with certain diagnostic or therapeutic procedures, but also due to their species, breed, size, and corresponding anatomy. Veterinary anesthesia includes anesthesia of the major species: dogs, cats, horses, cattle, sheep, goats, and pigs, as well as all other animals requiring veterinary care such as birds, pocket pets, and wildlife.
Post-dural-puncture headache (PDPH) is a complication of puncture of the dura mater. The headache is severe and described as "searing and spreading like hot metal", involving the back and front of the head and spreading to the neck and shoulders, sometimes involving neck stiffness. It is exacerbated by movement and sitting or standing and is relieved to some degree by lying down. Nausea, vomiting, pain in arms and legs, hearing loss, tinnitus, vertigo, dizziness and paraesthesia of the scalp are also common.
An epidural blood patch (EBP) is a surgical procedure that uses autologous blood, meaning the patient's own blood, in order to close one or many holes in the dura mater of the spinal cord, which occurred as a complication of a lumbar puncture or epidural placement. The punctured dura causes cerebrospinal fluid leak. The procedure can be used to relieve orthostatic headaches, most commonly post dural puncture headache (PDPH).
The thecal sac or dural sac is the membranous sheath (theca) or tube of dura mater that surrounds the spinal cord and the cauda equina. The thecal sac contains the cerebrospinal fluid which provides nutrients and buoyancy to the spinal cord. From the skull the tube adheres to bone at the foramen magnum and extends down to the second sacral vertebra where it tapers to cover over the filum terminale. Along most of the spinal canal it is separated from the inner surface by the epidural space. The sac has projections that follow the spinal nerves along their paths out of the vertebral canal which become the dural root sheaths.
Interventional pain management or interventional pain medicine is a medical subspecialty defined by the National Uniforms Claims Committee (NUCC) as, " invasive interventions such as the discipline of medicine devoted to the diagnosis and treatment of pain related disorders principally with the application of interventional techniques in managing sub acute, chronic, persistent, and intractable pain, independently or in conjunction with other modalities of treatment". Medicare Payment Advisory Commission (MedPAC) defined interventional techniques as, "minimally invasive procedures including, percutaneous precision needle placement, with placement of drugs in targeted areas or ablation of targeted nerves; and some surgical techniques such as laser or endoscopic diskectomy, intrathecal infusion pumps and spinal cord stimulators, for the diagnosis and management of chronic, persistent or intractable pain". Minimally invasive interventions such as facet joint injections, nerve blocks, neuroaugmentation, vertebroplasty, kyphoplasty, nucleoplasty, endoscopic discectomy, and implantable drug delivery systems are utilized in managing subacute or chronic pain.
The history of neuraxial anaesthesia dates back to the late 1800s and is closely intertwined with the development of anaesthesia in general. Neuraxial anaesthesia, in particular, is a form of regional analgesia placed in or around the Central Nervous System, used for pain management and anaesthesia for certain surgeries and procedures.
Caudal anaesthesia is a form of neuraxial regional anaesthesia conducted by accessing the epidural space via the sacral hiatus. It is typically used in paediatrics to provide peri- and post-operative analgesia for surgeries below the umbilicus. In adults, it can be used in the context of anorectal surgery or for chronic low back pain management.
