The Effects of Anesthesia on the Brain

Anesthesia is used to block nerve impulses so that the body and the brain can be desensitized to pain. Drugs used in anesthesia are referred to as analgesics. Types of analgesics include Ether, Choloroform, Insoflurane, Succinylcholine, Curare, Decamethonium and Gallamine. Certain drugs such as Ether and Choloroform are inhaled. Other drugs, such as Novacaine, are localized pain blockers that are applied with an injection or chemical drop. Benefits from using anesthesia are far reaching. As with all drugs, the procedure has side effects.

Types of Anesthesia

• Local, regional and general are the three basic types of anesthesia. Local anesthesia is most commonly used during dental procedures like tooth extractions and fillings. The procedure isolates the numbing or blocking of nerve impulses that send and receive data from the body to the brain in certain areas. For example, if you are having dental work performed, local anesthesia would only block nerve impulses in your mouth. The procedure is used when nerves are easier to reach via a needle injection or an inhalant, or by applying anesthesia directly to a small part of the body.

  Regional anesthesia blocks nerve impulses that communicate data to and from the body and the brain across a larger part of the body. The drugs are injected into bundles of nerves around the part of the body that is going to be operated on or that may be experiencing extreme pain. Spinal and epidural are two of the most commonly used forms of regional anesthesia. Regional procedures are used during caesarean sectional births and hip or back surgeries.

  General anesthesia impacts the entire body. Patients are taken into a state of unconsciousness. Drugs are entered into the body through a needle injection or by having the patient inhale medical gases. After the drugs are received by the brain, the body and the brain begin to numb. The state is referred to as controlled unconsciousness. It can take as long as an hour to recover or completely wake up from general anesthesia.

How Anesthesia Works

• Anesthesia works on the central nervous system. Think of the central nervous system as a telephone console. Neurons in the brain are like pushing buttons on the console to send and receive messages. Using the telephone console example, anesthesia keeps the nerves in your body or brain from touching buttons on the console to send and receive messages. This is the reason that a surgeon can perform an intensive operation on your body without you feeling or recalling the operation. Anesthesia drugs or analgesics also relax bodily muscles. More specifically and when using general anesthesia, the drugs inhibit neurons in the central nervous system from transmitting information to other neurons. Over time, this process slows down brain neurons and creates controlled unconsciousness.

Vision

• Because anesthesia effects brain neurons, the procedure can cause blurred, partial or complete loss of vision. Inhalant anesthesia is generally viewed as being safer than injections because it may cause less vasodilation, or the enlarging of blood vessels as smooth muscles relax. As blood vessels expand, blood flow through the vessels increases, which can cause problems. Patients who have an allergic reaction to anesthesia drugs may experience loss of vision if fluid emboli blocks an artery.

Cognitive Impact

• Typically the impact of anesthesia on the human heart was of concern. It and other effects of anesthesia on the brain and body are the reason that a licensed anesthesiologist remains with the patient pre-surgery through recovery. Studies continue to be conducted to measure the impact of anesthesia on a patient's cognitive brain functions. Patients have experienced problems focusing or concentrating following an anesthesia procedure. Some studies have noted that anesthesia can increase the numbers of amyloid plaques in animals, which has been linked to Alzheimer's. As with all medical procedures, report discomfort or changes to your physician. Typically the effects of anesthesia wear off within an hour to several days after the drugs are administered.

Delirium

• It is generally understood that delirium is caused by low levels of neurotransmitters, the event that occurs with the administration of analgesics. Patients who are already experiencing the onset of delirium or dementia might benefit from discussing analgesic options in the event that they have surgery. Arterial hypoxemia, which is caused when a pulmonary artery becomes blocked, might initiate the start of delirium or agitate an existing case of the illness. The lack of oxygen from the artery to the brain during surgery can cause post-operative medical conditions such as delirium that impact memory and mood.

Unconscious Recall of Surgical Events

• General anesthesia places the patient in a state of controlled unconsciousness. However, if not properly administered or if the patient has an allergic reaction to the drugs, he might remember parts of the surgery if the neurons in his brain continue to transmit information one to another. If this happens, patients might state that they remember seeing lights, hearing sounds or picking up scents from the operation room. There have also been reported instances of conscious pain awareness during use of regional anesthesia, such as when a woman feels pain during a caesarean section.