Anesthesia or anaesthesia from Greek word an- “without” and aisthesis, “sensation”). Traditionally meant the condition of having sensation (including the feeling of pain) blocked or temporarily taken away. It is a pharmacologically induced and reversible state of amnesia, analgesia, loss of responsiveness, loss of skeletal muscle reflexes or decreased stress response, or all simultaneously. This allows patients to undergo surgery without the distress and pain they would otherwise experience. An alternative definition is a “reversible lack of awareness,” including a total lack of awareness (e.g. a general anesthetic) or a lack of awareness of a part of the body (e.g. a spinal anesthetic).
Types of anesthesia include local anesthesia, regional anesthesia and general anesthesia. Local anesthesia inhibits sensory perception within a specific location on the body, such as a tooth. Regional anesthesia renders a larger area of the body insensate by blocking transmission of nerve impulses between a part of the body and the spinal cord. Two frequently used types of regional anesthesia are spinal anesthesia and epidural anesthesia. General anesthesia refers to inhibition of sensory, motor and sympathetic nerve transmission at the level of the brain, resulting in unconsciousness and lack of sensation.
In the UK the Association of Anesthetists (AAGBI) have set minimum monitoring guidelines for general and regional anesthesia. For minor surgery, this generally includes monitoring of Electrocardiography (ECG), heart rate, oxygen saturation (pulse oximetry), blood pressure, and inspired and expired concentrations for oxygen, carbon dioxide, and inhalational anesthetic agents. For more invasive surgery, monitoring may also include temperature, urine output, central venous pressure, pulmonary artery pressure and pulmonary artery occlusion pressure, cardiac output, cerebral activity, and neuromuscular function. In addition, the operating room environment must be monitored for ambient temperature and humidity, as well as for accumulation of exhaled inhalational anesthetic agents, which might be deleterious to the health of operating room personnel.
Allergic reaction to Anesthesia:
The incidence of life-threatening hypersensitivity reactions occurring during surgery and anesthesia is around 1:10,000 to 1:20,000 procedures. Serious allergic reactions to anesthetic medications are rare and a usually attributable to factors other than the anesthetic. Neuromuscular blocking agents, natural rubber latex, and antibiotics are the most common causes of serious allergic reactions during surgery.
Successful immediate treatment requires prompt recognition by the attending anaesthetist. Adrenaline (epinephrine) remains the mainstay of treatment, with corticosteroids and anti-histamines providing limited benefit in the acute situation.
Subsequent investigation aims to determine the responsible agent to allow its future avoidance. Skin testing is often useful to identify potentially cross-reactive compounds and appropriate therapeutic alternatives. This is done weeks after the initial reaction to allow the immune system to reset itself.
Dr. Emad Wilson Basta
GMC Hospital Fujairah