Anesthesia is a procedure that is administered to control pain, heart rate, blood pressure and other vital parameters during a surgical procedure. It is temporary state which allows the patient to recover and gain control of his coordination a few hours after a surgical procedure.
Anesthesia is an exact procedure which requires theoretical and practical expertise. Any kind of dosage variation can be fatal to the patient. During general anesthesia, patients are advised to abstain from eating and drinking 12 hours before the procedure as it may lead to aspiration associated complications during the procedure. Thorough examination of the patient history is done to evaluate for drug sensitivity and allergic patterns with respect to the type of anesthesia administered. Anesthetics such as inhalants or IV forms are given depending upon the type of surgical procedure.
General anesthesia is administered during complicated procedures such as cardio thoracic surgery, oncogenic or organ specific surgery. In this procedure, the patient goes into a stage of total unconsciousness with administration of anesthetic gases and intravenous anesthetics such as halothane, Sevoflurane, Enflurane, Desflurane, Isoflurane, Propofol, etomidate and thiopental. Some anesthetics such as Propofol are hypnotic in nature. It has been widely used because of its nature to bring back the patient to conscious state a few hours after the surgical procedure. In addition to the inhalant and intravenous forms of anesthesia which are administered, neuromuscular blockage is also required as it helps in respiratory ventilation along with intubation. Most of these neuromuscular blockade agents are derived from curare compounds which is a skeletal muscle relaxant.
Local anesthetics are either administered as a combination with general anesthetics are as a post-operative anesthetic agent. Most of the local anesthetics are amides and esters. Some of the local anesthetic amides include lidocaine, prilocaine, ropivacaine and etidocaine. The ester forms of these anesthetics include tetracaine, procaine, cocaine and benzocaine. Local anesthetic drugs are given directly in the region where the surgical procedure has to take place. Most dental procedures involve the administration of local anesthetics. The patient is conscious and experiences numbness only in the region where the procedure is being done.
This form of anesthesia is given to block pain in a larger area of the body where the procedure is done. Patient is sedated in most cases. Regional anesthetic drugs usually work on the principle of nerve block caused in the peripheral region. This includes a procedure called spinal anesthesia where the drug is administered in a specific area of the spine to numb the corresponding region of the body. Regional anesthesia is administered at a specific location to numb the region for surgical intervention. Local anesthetics are administered either in the topical or injectable form to desensitize the area of surgical intervention.
Risk factors of anesthesia
Malignant hyperthermia is one of the rare yet life threatening complications of anesthesia. This adverse reaction is caused when succinyl choline (muscle relaxant) is administered. In this reaction, the muscle fibers of the body tend to dissociate from each other. Spinal and epidural anesthetic procedures have headaches as side effects due to the leakage of cerebrospinal fluid from region of injection. Nausea, vomiting and nerve damages are some of the predominant side effects of anesthetic procedures. These are controlled by administration of IV medications. In some patients, the insertion of endotracheal tube during procedures such as bronchoscopy may lead to sore throat for a few days. Apart from all the presumptive risk factors and side effects of anesthetic drugs, some have toxic effects on liver and kidneys. In such conditions, patients are examined for tolerance and toxicity before administering anesthetic gases such as halothane.
An anesthetist is also called an anesthesiologist. An anesthetist administers anesthetic to patients, who are going to undergo surgery or procedure. With a local anesthetic, the patient is numb only in a designated area where the medication is administered. General anesthetic involves a procedure where a patient is prepared for surgery by going to sleep and having sensation temporarily blocked. Anesthesia ensures that the surgical procedure be done without distress to the patient.
A nerve block, an anesthetic injection, is used in the management of severe pain. Nerve blocks are not only used to reduce pain and inflammation but also as a pointer for identifying specific source of pain. It involves injection of a local anesthetic to specific nerves. When regional anesthesia is needed for surgery, a nerve block is often used to numb the targeted set of nerves. In surgical cases, a 'nerve catheter' might be placed to continually supply the nerves with numbing medication and prevent severe pain to the patient. Nerve blocks are more effective than IV anesthetics.
Nerve blocks are used in cases of severe pain such as Raynaud's syndrome, chronic abdominal pain, severe back pain and reflex sympathetic dystrophy. This procedure is done with imaging guidance from fluoroscopy, ultrasound or CT. It allows the radiologist to view the needle movement and guide it to the right location. Soon the patient experiences numbness and pain relief. A nerve block works by blocking or reducing the signals sent to the brain. The risks of bleeding, infection, nerve injury and allergic reaction are associated with nerve block injections.
Bibliography / Reference
Collection of Pages - Last revised Date: March 23, 2019