The word anesthesia means loss of sensation [1]. Anesthesia is the use of medicine to keep you safe, comfortable and to stop you from feeling pain during surgical procedure either for therapy or diagnosis. It does this by blocking the pain signals that pass along your nerves to your brain [2]. 

Not all types of anesthesia make you unconscious, anesthesia can be given in various ways and can be applied to different parts of the body. Different types of anesthesia may be used either alone or in combination to obtain the desired results for your surgery/procedure. Anesthesia has made much of today’s surgery possible and has brought great benefits. Modern anesthesia is very safe and can be tailored to your individual needs and to suit type of surgery the individual having [3]. 

Anesthesiologist or Anesthetist are doctors who have had specialist training in anesthesia and also in the treatment of pain, intensive care and emergency care, anesthetist is responsible for patient wellbeing and safety throughout surgery procedure, also, in charge for planning patient’s pain control and managing any transfusions of medicine or blood that may patient need [4].

Physician anesthesiologists evaluate, monitor and supervise patient care before, during and after surgery, delivering anesthesia, leading the Anesthesia Care Team and ensuring optimal patient safety. Physician anesthesiologists specialize in anesthesia care, pain management and critical care medicine. The main roles of the anesthesiologist is to avoid happen anesthesia risks, side effects and complications, and planning in advance to overcome any of previous mentioned consideration [5]. 

It can be distilled down roles of the anesthesiologist in elective surgery into these basic goals. Which include, enable a successful and faster recovery of the patient post operatively through choose the best plan for perioperative care. In addition, to reduce perioperative morbidity and mortality rate. Furthermore, to reduce the length of hospital stay of the patient. Moreover, to provide quality care service for perioperative care and to reduce hospital and patient cost during perioperative period [6].

Objectives

The present review highlights the roles of anesthesiologist, types, risks, side effects, and medications of anesthesia, perioperative care, anesthetic preparation, and anesthetic check-up.

Type of Anesthesia

There are several classifications for different anesthesia types that may be used individually or in combination, depending on the nature of surgery and patient's state. Which include general, regional and local anesthesia [2].

General anesthesia is suppressing the activity of the central nervous system and leads to loss of consciousness and total absence of sensation. It is necessary for major operations that need temporarily loss of consciousness, so your brain does not recognize any signal of pain. This type of anesthesia can be administered by inhalation agents as the gases or vapors you breathe through a mask or tube, and by an intravenous (IV) line through your vein. With this type of anesthesia, you will be completely asleep [7].

Regional anesthesia eliminates sensation in a larger part of the body. It blocks the spinal cord or groups of nerves, or a combined technique can be performed in the region of the central nervous system itself so pain signals cannot reach the brain. This type of anesthesia is used for certain procedures of the chest, abdomen, pelvis, arms or legs. You can stay awake during the procedure or receive additional medication to keep you sedated or a sleep [8].

Local anesthesia in many anesthesia books is considering as branch of regional anesthesia. In this type of anesthesia, the small part of the body will be anesthetized where patient will have surgery. Anesthetic medicines are injected or applied to the surface of the skin, nose or mouth to temporarily block nerves in the surgical area. This type of anesthesia is used for minor procedures. Since local anesthesia only affects the nerves in the surgical area and not your brain, you may be awake during the procedure [9]. 

Risks and Side Effects of Anesthesia

All procedures have risks, which depend on factors, including your type of surgery, type of anesthesia and your medical condition. Fortunately, these risks are rare and the anesthesiologist takes every precaution to prevent them from occurring [10]. Some of the risks of undergoing anesthesia are allergic reaction to the medicine, aspiration pneumonia (inhaling stomach contents into the lungs), infection, bleeding, heart attack, stroke, nerve damage, hyperthermia (very high temperature), visual disturbances or loss of sight, cognitive dysfunction, and the worst Scenario among risks is death. Some of these complications are related to the procedure and/or your position during the procedure. The risks increase with the duration of the procedure [11]. Very long procedures have a higher risk of complications. Your anesthesiologist will take all necessary steps to reduce the risk of complications from the moment you enter the operating room until you are comfortable in the recovery room. Having regional anesthesia instead of general anesthesia does not necessarily reduce the risk of complications. Regional anesthesia is not always possible and the expected effects of regional anesthesia are less predictable than general anesthesia [3].

Common side effects of anesthesia include headache, sleepiness, nausea, vomiting, thirst and shivering can occur to a greater or lesser degree with all types of anesthesia [12]. However, other more specific side effects that may patient experience which depend on the type of anesthesia are given [3].  The more common side effects associated with the different types of anesthesia include for instance, local or regional anesthesia may give you muscle weakness, numbness, tingling, nausea, backache or headache [13]. Monitored anesthesia care may lead to feel of headache, sleepiness or nausea and vomiting [14]. While, with general anesthesia you may feel nausea, thirst, shivering or a sore throat or jaw. Expects all these situations and may be able to provide some relief [15].Medications for Anesthesia

Classification of anesthetics’ medications which may be divided into two broad classes: general anesthetics drugs, which result in a reversible loss of consciousness. And both regional and local anesthetics medicines, which cause a reversible loss of sensation for a limited region of the body without necessarily affecting consciousness [16].

A wide variety of drugs are used in modern anesthetic practice. Many are rarely used outside of anesthesia, but others are commonly used in various areas of health care. Combinations of anesthetics are sometimes used for their synergistic and additive therapeutic effects. However, side effects may also be increased. Anesthetics are distinct from analgesics, which only block the sensation of painful stimuli [17].

General anesthetics medications can be classified according to the ways of given into inhaled anesthetics agents and intravenous anesthetics agents. The last one is further subdivide in intravenous opioid analgesic agents and intravenous non-opioid agents [18].

Inhaled anesthetics agents are specially formulated organic liquids that evaporate readily into vapors, and are given by inhalation for induction or maintenance of general anesthesia. The ideal anesthetic vapor or gas should be non-flammable, non-explosive, and lipid-soluble. It should possess low blood gas solubility, have no end-organ toxicity or side-effects, should not be metabolized, and should not be an irritant to the respiratory pathways of the patient [19]. In theory, any inhaled anesthetic agent can be used for induction of general anesthesia. However, most of the halogenated anesthetics are irritating to the airway, perhaps leading to coughing, laryngospasm and overall difficult inductions. All of the inhaled agents can be used alone or in combination with other medications to maintain anesthesia. No inhaled anesthetic agent currently in use meets all these requirements, nor can any anesthetic agent be considered safe [20].

Inhaled anesthetics agents are frequently compared in terms of potency, which is inversely proportional to the minimum alveolar concentration. Potency is directly related to lipid solubility. This is known as the Meyer-Overton hypothesis. However, certain pharmacokinetic properties of volatile agents have become another point of comparison. Most important of those properties is known as the blood/gas partition coefficient. This concept refers to the relative solubility of a given agent in blood. Those agents with a lower blood solubility give the anesthesia provider greater rapidity in titrating the depth of anesthesia, and permit a more rapid emergence from the anesthetic state upon discontinuing their administration. In fact, newer volatile agents have been popular not due to their potency, but due to their versatility for a faster emergence from anesthesia, thanks to their lower blood–gas partition coefficient. Some examples for inhaled anesthesia drugs include desflurane, enflurane, halothane, isoflurane, methoxyflurane, nitrous oxide and sevoflurane [21].

With regard to the subject of intravenously agents, there are many non-opioid intravenous drugs that can be used intravenously to produce anesthesia or sedation. The most common of these are barbiturates, benzodiazepines, etomidate, ketamine and propofol. barbiturates, thiopental and methohexital, are ultra-short-acting and are used to induce and maintain anesthesia. However, although they cause loss of consciousness, they provide no pain relief and should be used with other agents. Benzodiazepines can be used for sedation before or after surgery and can be used to induce and maintain general anesthesia. When benzodiazepines are used to induce general anesthesia, midazolam is preferred. Like barbiturates, benzodiazepines have no analgesic properties. Propofol is one of the most commonly used intravenous drugs to induce and maintain general anesthesia. Because of its favorable physiological effects, Ketamine is rarely used in anesthesia because of the unpleasant experiences that sometimes occur at the end of anesthesia, which include vivid dreams, extracorporeal experiences, and illusions [22].

While intravenous opioid analgesic agents can produce unconsciousness, they do so unreliably and with significant side effects. So, while they are rarely used to induce anesthesia, they are frequently used along with other agents such as intravenous non-opioid anesthetics or inhalational anesthetics. Furthermore, they are used to relieve pain of patients before, during, or after surgery. Some opioids have short onset and duration of action and are frequently used during general anesthesia such as alfentanil, fentanyl, remifentanil and sufentani. while other agents have longer onset and duration of action and are frequently used for post-operative pain relief for instance buprenorphine, morphine, hydromorphone, pethidine, methadone, pentazocine also known as heroin, which not permit for use as an analgesic in any country [23]. 

Regional and local anesthetic agents prevent the transmission of nerve impulses without causing unconsciousness. They work by reversibly binding to the fast sodium channels inside the nerve fibers, thereby preventing sodium from entering the fibers, stabilizing the cell membrane and preventing the spread of action potential. Each of the regional or local anesthetics has the suffix "-caine" in their names. Local anesthetics can be based on ester or amide. Local anesthetics based on ester (such as procaine, amethocaine, cocaine, benzocaine, tetracaine) are generally unstable in solution and fast acting, are rapidly metabolized by cholinesterases in blood plasma and the liver, and most often cause allergic reactions. Local amide anesthetics (such as lidocaine, prilocaine, bupivicaine, levobupivacaine, ropivacaine, mepivacaine, dibucaine and etidocaine) are generally thermostable, with a long shelf life (approximately two years). Amides have a slower onset and longer half-life than ester anesthetics, and are generally racemic mixtures. Amides are generally used in regional and epidural or vertebral techniques, because of their longer duration of action, which provides adequate analgesia for surgery, labor, and symptom relief [24].

Perioperative Care

The perioperative care/nursing is accepted and used in medical literature that was formerly referred to as “operating room care/nursing”, a term that historical denoted to patient care provided in the intraoperative period and administered within the operating room itself. Then, the responsibility of patient care expanded to include care in the preoperative and postoperative periods, the word perioperative was recognized as more appropriate. The organization that represents perioperative are “Association of Operating Room/Registered Nurses” (AORN) [25].

The perioperative care period begins when the patient is informed of the necessity for surgery and continued with surgical procedure and recovery, which end when the patient resumes his/her usual activities. The surgical experience can be segregated into three phases include preoperative, intraoperative and postoperative. The term perioperative is used to encompass all three phases. The perioperative nurse provides nursing care during all three phases [26].

The pre-operative phase initiates when the patient is informed of the necessity for operation and makes the decision to have the procedure. This phase ends when the patient is transferred to the surgery room bed. The preoperative phase is the period that is started with diagnostic study and medical investigation to obtained information from preoperative assessment and interview which then used to prepare a plan of care for the patient. Prepare patient physically and psychologically through supporting and instruction him/her for procedure [27].

The intraoperative phase starts when the patient is transferred to operative room bed and ends with transfer to the post anesthesia care unit (PACU) or another zone where immediate postsurgical recovery care is given. During this period, the patient is monitored, anesthetized, prepped, draped and the procedure is performed. Here, the care focus on patient safety, facilitation of procedure, prevention of infection and satisfactory physiology response to anesthesia and surgical intervention [26].

Regarding the postoperative phase which begins with the patient’s transfer to recovery unit and ends with resolution of surgical sequelae. The care activities in the immediate postoperative phase center on support of patient’s physiologic system. In the later stages of recovery, much of the focus is on reinforcing the essential information that the patient and other caregivers require in preparation for discharge [28]. 

Overall, the goal of perioperative care is to assist patient and their family in making decision and to meet and support the needs of patient undergoing surgical or other invasive procedure and achieve a level of wellness greater than the level prior to surgery. That will done through five steps include assessment, diagnosis, planning, intervention and evaluation of care process through whole period [29].

Anesthetic Preparation

The anesthetic preparation involves procedures which are implemented based on the nature of the expected operation, anesthesia as well as the findings of the diagnostic workup and the pre anesthetic checkup. Therefore, the preparation would not be the same for all [30].

Surgical procedures and administration of anesthesia are associated with a complex stress response that is proportional to the magnitude of injury, total operating time, amount of intraoperative blood loss and degree of postoperative pain. The adverse metabolic and hemodynamic effects of this stress response can present many problems in the perioperative period. Decreasing the stress response to surgery and trauma is the key factor in improving outcome and lowering the length of hospital stay as well as the total costs of patients’ care [31].

It is well recognized that safe and efficient surgical and anesthesia practice requires an optimized patient. The large-scale epidemiological studies have indicated that inadequate preoperative and anesthetic preparation of the patient may be a major contributory factor to causes of perioperative morbidity and mortality. Patient must follow the instructions that has received about when to stop eating and drinking. The usual advice is to stop eating solid foods 8 hours in advance of patient scheduled arrival, and to stop taking clear liquids 2 hours in advance [30]. 

The patient with bad habit as smoking or drinking, who is scheduled for surgery, it is recommend that patient take immediate steps to stop smoking and drinking at once, and remain smoke-free until at least one week following your procedure or forever. Quitting smoking is one of the best thing's patient can do to recover from surgery without complications? People who smoke have an increased chance of complications including wound infections, pneumonia, and heart attacks. The sooner you stop smoking, the better your chances of a smooth recovery [32].

The patient who takes more than one or two medications, he/she must bring the list of medication with him/her, including any herbal or "natural" medications. If patient have a complicated medical history, it may be helpful to bring a written summary of major health issues, any operations, and any problems patient may have had with anesthesia. After surgery, a wearing comfortable clothing that is easy to put on and will fit easily over any bandage or surgical dressing is important. It is a good idea for patient remove all jewelry and valuables things and any tight things as ring before coming hospital [33].

Generally, the main goal for anesthetic preparation is to prepare patient physiologically, psychologically socially as well as planning of perioperative care through minimize, the predisposing factors and causes of perioperative morbidity and mortality [34].

Anesthetic Check-up

Pre anesthetic assessment also called pre anesthesia evaluation, Pre-anesthesia checkup (PAC) or simply pre anesthesia is a medical checkup, physical examination and laboratory investigations done by the anesthesiologist before an operation, to assess the patient's physical condition and any other medical problems or diseases [35]. The aim of the assessment is to identify factors that significantly increase the risk of complications, and modify the procedure appropriately. And to identify the appropriate anesthetic techniques to be used, to ensure the safety of perioperative care, optimal resource use, improved outcomes, and patient satisfaction, while considering the individual and person related risk factors and circumstances. The pre anesthetic assessment involves the consideration of information from various sources that include the past medical records, interview, physical examination, as well as results from an appropriate medical and laboratory tests. Within the patient’s medical history aspects relating to the cardiovascular and respiratory systems are relatively more important to the anesthetist than the other areas. A mnemonic has been suggested for pre anesthetic assessment, to ensure that all aspects are covered [36].

It can be concluded that there are several different types of anesthesia. The risks of undergoing anesthesia are allergic reaction to the medicine, aspiration pneumonia, infection, bleeding, heart attack, stroke, nerve damage, hyperthermia, visual disturbances or loss of sight, cognitive dysfunction, and the worst Scenario among risks is death. Common side effects of anesthesia include headache, sleepiness, nausea, vomiting, thirst, and shivering. The goal of perioperative care is to assist patient and their family. The main goal for anesthetic preparation is to prepare patient physiologically, psychologically and socially. Briefly, the most excellent anesthetic check-up leads to prepare the best perioperative care and the finest anesthetic preparation as result avoid or minimize risks, side effects, and complications of Anesthesia.

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