Anesthesiology: History and Basic Concepts

Introduction

Definition

Anesthesiology is the field of medicine focusing on interventions that bring about a state of anesthesia, which is characterized by a reversible loss of consciousness, as well as analgesia, amnesia, and muscle relaxation.

State of anesthesia

• Induced via the administration of gaseous or injectable agents before surgical procedures or other medical interventions
• Effects:
  • Analgesia: relief from pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways or the prevention of pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Amnesia: loss of awareness and/or memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment of pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways/experience
  • Hypnosis: temporary unconsciousness or the absence of anxiety Anxiety Feelings or emotions of dread, apprehension, and impending disaster but not disabling as with anxiety disorders. Generalized Anxiety Disorder
  • Paralysis: adequate muscle relaxation

Certified personnel who perform and manage anesthesia

• Anesthesiologists
• Certified registered nurse anesthetists
• Anesthesia assistants

Settings where anesthesia is performed

• ORs
• EDs
• Endoscopy Endoscopy Procedures of applying endoscopes for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. Transluminal, to examine or perform surgery on the interior parts of the body. Gastroesophageal Reflux Disease (GERD) suites
• Interventional radiology Interventional radiology Subspecialty of radiology that combines organ system radiography, catheter techniques and sectional imaging. Penetrating Abdominal Injury suites
• Interventional cardiology laboratories
• Ambulatory surgical centers (centers for “day surgery”)
• Post-anesthesia care units (PACUs)
• ICUs

History

• The practice of medicine was transformed in the middle of the 19th century with the discovery of general anesthesia.
• In previous centuries, surgery was performed as a last resort and desperate measure due to the unbearable pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways it caused.
• The use of chemical compounds to induce a state of anesthesia in modern medicine dates back to the 18th century with the introduction of inhaled anesthetics Inhaled anesthetics Inhaled anesthetics are chemical compounds that can induce and maintain general anesthesia when delivered by inhalation. Inhaled anesthetics can be divided into 2 groups: volatile anesthetics and gases. Volatile anesthetics include halothane, isoflurane, desflurane, and sevoflurane. Inhaled Anesthetics.

Preoperative Evaluation

Focused evaluation and planning for anesthesia should be completed in advance for all surgeries, interventions, and procedures.

• Risk stratification is an important part of preoperative planning.
• Low-risk individuals can be evaluated immediately before anesthesia on the day of the procedure.
  • Low-risk individuals are those who are:
    • < 65 years of age
    • Having stable and adequately controlled medical conditions
    • Undergoing low-risk procedures
  • Risk increase with:
    • Age
    • Complexity of comorbid medical conditions
    • Complexity of planned anesthesia and/or medical/surgical procedures
    • Duration of planned anesthesia and/or medical/surgical procedures
• Intermediate-to-high risk may need stabilization and/or optimization of comorbid medical conditions prior to anesthesia and/or planned procedures.
• Emergency anesthesia and/or planned procedure necessitate the initiation of measures with minimal preparation time and are, by their very nature, high risk.

Goals

• Assessing medical status and readiness for the planned procedure
• Reducing the risks of anesthesia and surgery
• Creating an anesthetic plan and preparing the individual

Components of preoperative evaluation

• Clinical evaluation:
  • Medical history
  • Current medications
  • History of prior anesthesia and surgeries
  • Physical examination
• Risk assessment Risk assessment The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. Preoperative Care:
  • Evaluation of factors that increase the likelihood of perioperative morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status and mortality Mortality All deaths reported in a given population. Measures of Health Status
  • An objective observation commonly used by the anesthesiology team to create ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing and intubation Intubation Peritonsillar Abscess plans
  • Assessment of the anatomy of the head and neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess to determine the difficulty of intubation Intubation Peritonsillar Abscess:
    • Mallampati classification Mallampati Classification Preoperative Care is used to assess ease of airway Airway ABCDE Assessment access for intubation Intubation Peritonsillar Abscess.
    • Graded I–IV based on the difficulty associated with oropharyngeal characteristics
  • Inclusion of the individual’s underlying health problems
  • Identification Identification Defense Mechanisms of medication allergies Allergies A medical specialty concerned with the hypersensitivity of the individual to foreign substances and protection from the resultant infection or disorder. Selective IgA Deficiency
  • Response to prior anesthesia methods
  • Other aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS in risk assessment Risk assessment The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. Preoperative Care include:
    • Prognostic biomarkers (e.g., B-type natriuretic peptide)
    • CBC (to rule out anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types, infection, thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia)
    • Electrolyte panel (to evaluate electrolyte imbalance and metabolic disturbance)
    • Coagulation studies Coagulation studies Coagulation studies are a group of hematologic laboratory studies that reflect the function of blood vessels, platelets, and coagulation factors, which all interact with one another to achieve hemostasis. Coagulation studies are usually ordered to evaluate patients with bleeding or hypercoagulation disorders. Coagulation Studies (to evaluate for coagulopathy)
    • Creatinine, GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests
    • CRP
    • Functional status/ability to engage in daily activities as reported subjectively by the individual
• Optimization of diseases and comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus:
  • Optimally managing and treating comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus before surgery and anesthesia to decrease morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status and mortality Mortality All deaths reported in a given population. Measures of Health Status
  • Common examples include:
    • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • Ischemic heart disease Ischemic heart disease Coronary heart disease (CHD), or ischemic heart disease, describes a situation in which an inadequate supply of blood to the myocardium exists due to a stenosis of the coronary arteries, typically from atherosclerosis. Coronary Heart Disease
    • Heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
    • Obstructive sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea
    • Diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • Thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy disease
    • Anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types
  • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation at least 2 weeks before surgery
• Preoperative testing:
  • Diagnostic testing for preexisting conditions and comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus should be obtained preoperatively to monitor conditions postoperatively.
  • Patient-specific testing, for example:
    • If blood transfusion is anticipated, blood typing and crossmatching Crossmatching Testing erythrocytes to determine presence or absence of blood-group antigens, testing of serum to determine the presence or absence of antibodies to these antigens, and selecting biocompatible blood by crossmatching samples from the donor against samples from the recipient. Crossmatching is performed prior to transfusion. Transfusion Reactions are imperative before surgery and anesthesia.
    • If a woman of childbearing age is to undergo surgery and anesthesia, a pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care test is indicated to avoid fetal loss.

Patient education

• Essential for the affected individual’s satisfaction and safety
• Provides information on how to reduce the risks of surgery and anesthesia:
  • Stop smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases before and after surgery.
  • Medications that are to be taken or avoided before surgery
  • Cessation of eating and drinking by midnight prior to the procedure to prevent aspiration of gastric contents
  • Sanitary measures prior to the procedure (e.g., antibacterial Antibacterial Penicillins soap prep)
• Involve the individual in the decision-making and planning steps.
• Answer all questions.
• Address all concerns.

Informed consent Informed consent Informed consent is a medicolegal term describing the documented conversation between a patient and their physician wherein the physician discloses all relevant and necessary information to a patient who is competent to make an informed and voluntary decision regarding their care. Competency, disclosure, and voluntariness are the key elements upon which IC is based. Informed Consent

• Based on the premise that individuals have the right to receive information and ask questions about recommended treatments so that they can make well-informed decisions about their care
• Treating physicians Physicians Individuals licensed to practice medicine. Clinician–Patient Relationship should discuss all risks and complications associated with the procedure and associated anesthesia before asking for informed consent Informed consent Informed consent is a medicolegal term describing the documented conversation between a patient and their physician wherein the physician discloses all relevant and necessary information to a patient who is competent to make an informed and voluntary decision regarding their care. Competency, disclosure, and voluntariness are the key elements upon which IC is based. Informed Consent.
• Results in the individual’s agreement or refusal to undergo a specific medical intervention
• Usually obtained in a written format

Anesthesia plan

The creation of a plan for anesthesia involves the consideration of:

• Surgery requirements
• Duration of surgery
• Comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus
• Postoperative considerations
• The individual’s preference
• Preferences of the surgeon and the anesthesiologist

Postoperative care Postoperative care After any procedure performed in the operating room, all patients must undergo close observation at least in the recovery room. After larger procedures and for patients who require hospitalization, observation must continue on the surgical ward. The primary intent of this practice is the early detection of postoperative complications. Postoperative Care

Considerations include:

• Pain management Pain Management Pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Pain is a subjective experience. Acute pain lasts < 3 months and typically has a specific, identifiable cause. Pain Management
• Hemodynamics Hemodynamics The movement and the forces involved in the movement of the blood through the cardiovascular system. Vascular Resistance, Flow, and Mean Arterial Pressure
• Pulmonary hygiene
• Early interventions
• Requirement of ICU ICU Hospital units providing continuous surveillance and care to acutely ill patients. West Nile Virus vs appropriate hospital wing vs outpatient care for recovery

Types of Anesthesia

Several types of anesthesia are used for surgery or other medical procedures. Choosing the appropriate type depends on:

• Procedure to be performed
• Procedure requirements
• Area that needs to be anesthetized
• Duration of surgery
• Patient-specific comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus
• Postoperative anesthesia plans and considerations
• Individual’s preference
• Preferences of the provider and the anesthesiologist

Types of anesthesia:

• General
• Neuraxial
• Peripheral nerve block
• IV regional anesthesia
• Monitored anesthesia care (MAC)

General anesthesia

• Drug-induced loss of consciousness
• Affects the whole body
• Appropriate for most major surgical procedures
• The goal of general anesthesia is to attain:
  • Unconsciousness
  • Analgesia
  • Muscle relaxation with immobility
  • Blockage of noxious stimuli during surgery

The 3 stages of general anesthesia are:

1. Induction:
   • Accomplished via inhalation or IV
   • Airway management Airway management An airway, breathing, and circulation (ABC) assessment is the mainstay for evaluating and treating critically ill individuals. The airway assessment helps identify individuals with potential obstruction of the airway, which may benefit from airway management techniques to ensure adequate ventilation and oxygenation. Airway Management is integral and is initially via a face mask followed by the transition to endotracheal intubation Intubation Peritonsillar Abscess.
2. Maintenance:
   • Typically achieved via a primary inhalation technique using IV drugs
   • Goal is to reduce the total dosage Dosage Dosage Calculation of any 1 agent; thus, anesthetic combinations are commonly used.
3. Emergence:
   • Involves removing anesthetic agents and reversing their residual effects for the return of consciousness and movement
   • Extubation Extubation Removal of an endotracheal tube from the patient. Invasive Mechanical Ventilation can be performed when the individual can protect their airway Airway ABCDE Assessment, follow simple commands, and ventilate without assistance.

Neuraxial anesthesia

• A type of anesthesia that involves anesthetizing the nerves of the CNS
• Neuraxial anesthesia is commonly used for lower abdominal and lower extremity surgeries or for pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways relief.
• 2 main types:
  • Spinal anesthesia: A needle is inserted between the vertebrae and the anesthetic is injected directly into the subarachnoid space Subarachnoid space The space between the arachnoid membrane and pia mater, filled with cerebrospinal fluid. It contains large blood vessels that supply the brain and spinal cord. Subarachnoid Hemorrhage.
  • Epidural anesthesia: A catheter is inserted between the vertebrae and the anesthetic is injected directly into the epidural space Epidural space Space between the dura mater and the walls of the vertebral canal. Epidural Hemorrhage.

Peripheral nerve blocks

• A type of regional anesthesia
• The anesthetic is injected near a specific nerve or a bundle of nerves to block sensations of pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways from a specific area of the body.
• Commonly used for procedures involving the upper and lower extremities
• Fluoroscopy Fluoroscopy Production of an image when x-rays strike a fluorescent screen. X-rays or ultrasound guidance is often used for needle or catheter insertion and placement.
• Long-acting local anesthetics Local anesthetics Local anesthetics are a group of pharmacological agents that reversibly block the conduction of impulses in electrically excitable tissues. Local anesthetics are used in clinical practice to induce a state of local or regional anesthesia by blocking sodium channels and inhibiting the conduction of painful stimuli via afferent nerves. Local Anesthetics provide prolonged postoperative analgesia.

Intravenous regional anesthesia Intravenous Regional Anesthesia Inhaled Anesthetics ( IVRA IVRA Inhaled Anesthetics)

• Also known as a “ Bier block Bier Block Complex Regional Pain Syndrome (CRPS)”
• Less invasive alternative to peripheral nerve blocks
• Suitable for shorter procedures of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy, forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy, and foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
• Estimated blockage time: approximately 1.5 hours
• Appropriate for surgeries lasting 1 hour or less
• Procedure:
  1. Compression Compression Blunt Chest Trauma and exsanguination of the extremity using an Esmarch bandage
  2. A tourniquet is used to keep the blood out of the extremity and retain anesthesia.
  3. An infusion of 0.5% lidocaine Lidocaine A local anesthetic and cardiac depressant used as an antiarrhythmic agent. Its actions are more intense and its effects more prolonged than those of procaine but its duration of action is shorter than that of bupivacaine or prilocaine. Local Anesthetics via a peripheral vein establishes anesthesia.
  4. The surgeon can work in a completely anesthetized and bloodless surgical field for a limited time.

Monitored anesthesia care

• Involves monitoring an individual’s vitals and administering sedatives, anxiolytics, or analgesics accordingly
• Commonly used during outpatient procedures
• If needed, anesthesiologists are ready to convert to general anesthesia at any time.
• A common example is administering propofol Propofol An intravenous anesthetic agent which has the advantage of a very rapid onset after infusion or bolus injection plus a very short recovery period of a couple of minutes. Propofol has been used as anticonvulsants and antiemetics. Intravenous Anesthetics whenever an anesthesiologist deems it necessary during an endoscopy Endoscopy Procedures of applying endoscopes for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. Transluminal, to examine or perform surgery on the interior parts of the body. Gastroesophageal Reflux Disease (GERD) based on the individual’s vitals and mobility.

Perioperative Monitoring

Standard monitors

• Used by the anesthesiology team during a procedure
• Includes:
  • Pulse oximetry
  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)
  • Noninvasive blood pressure monitoring device
  • Thermometers
  • Integrated monitors with alarms

Monitoring of ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing

• Serialized visual inspection Inspection Dermatologic Examination, auscultation, palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination, and O₂ saturation
• Ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing monitoring is essential during anesthesia due to the risk of respiratory depression and hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage.
• Ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing is monitored in several ways:
  • Clinical monitoring:
    • Visualization of chest excursion
    • Auscultation of breath sounds
    • Movement of the reservoir Reservoir Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers. Escherichia coli bag
    • O₂ saturation monitor
  • Capnography: a graph showing the respiratory rate Respiratory rate The number of times an organism breathes with the lungs (respiration) per unit time, usually per minute. Pulmonary Examination and CO₂ concentration over time
  • Other measures:
    • End-tidal CO₂ concentration
    • Inspired O₂ concentration
    • Quantitative volume of expired gas

Monitoring of hemodynamics Hemodynamics The movement and the forces involved in the movement of the blood through the cardiovascular system. Vascular Resistance, Flow, and Mean Arterial Pressure

• Serialized recording of automated blood pressure, ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG), and HR
• More accurate hemodynamic monitoring can be achieved via invasive approaches such as:
  • Intra-arterial pressure monitor
  • Central venous pressure Central venous pressure The blood pressure in the central large veins of the body. It is distinguished from peripheral venous pressure which occurs in an extremity. Central Venous Catheter monitor
  • Pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy catheter
  • Transesophageal echocardiography Transesophageal echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus. Imaging of the Heart and Great Vessels ( TEE TEE Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus. Imaging of the Heart and Great Vessels) probes
• Hemodynamics Hemodynamics The movement and the forces involved in the movement of the blood through the cardiovascular system. Vascular Resistance, Flow, and Mean Arterial Pressure are monitored based on:
  • Vitals signs
  • Fluids (IV input and urine output)
• Vasoactive drugs can be administered to maintain optimal intravascular volume status Volume Status ACES and RUSH: Resuscitation Ultrasound Protocols throughout anesthesia.

Monitoring of neurologic status

• Neurologic status may be difficult to assess in individuals who are sedated and/or paralyzed.
• EEG EEG Seizures may be used for the neuromonitoring of cortical function.
• IM paraspinal and/or limb electrodes Electrodes Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum. Electrocardiogram (ECG) may be used to monitor nerve stimulation during neurosurgical, orthopedic, or interventional spinal procedures.
• Intracranial pressure Intracranial Pressure Idiopathic Intracranial Hypertension may be monitored during neurosurgical procedures.

Depth of anesthesia

• Monitored based on end-tidal concentrations of inhalation anesthetics
• The goal of anesthesia is stage II or III, depending on the type of anesthesia chosen.
• Stage III requires endotracheal intubation Intubation Peritonsillar Abscess for airway Airway ABCDE Assessment protection.
• If the desired stage III enters stage IV, prompt reversal is necessary.

Postoperative Care

All individuals are monitored postoperatively in a PACU, where standard procedures are followed:

• Antiemetics Antiemetics Antiemetics are medications used to treat and/or prevent nausea and vomiting. These drugs act on different target receptors. The main classes include benzodiazepines, corticosteroids, atypical antipsychotics, cannabinoids, and antagonists of the following receptors: serotonin, dopamine, and muscarinic and neurokinin receptors. Antiemetics for postoperative nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics and/or vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
• Fluid administration and monitoring for the inability to void via strict inputs and outputs
• Respiratory, cardiovascular, and neurological monitoring
• Monitoring and control of hypothermia Hypothermia Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia and hyperthermia
• Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways control
• Reassurance Reassurance Clinician–Patient Relationship, reorientation, and potential drug reversal for delayed emergence (failure to return to a conscious state within 60 minutes of anesthesia cessation)
• Recovery assessment
• Reduction of postoperative adverse events
• Streamline discharge
• Transferring to an ICU ICU Hospital units providing continuous surveillance and care to acutely ill patients. West Nile Virus vs appropriate hospital wing vs outpatient care for recovery