C-AA key terms

The alveolar concentration of a volatile anesthetic at one atmosphere that prevents movement in 50% of patients in response to a standardized surgical stimulus. It compares potency and guides dosing.

The dose or concentration of a drug required to produce a given effect. For inhaled anesthetics, a lower MAC indicates higher potency; for intravenous drugs, the effective dose reflects potency.

The time required for plasma concentration of an intravenous drug to decrease by half after stopping an infusion. It depends on infusion duration and redistribution and predicts recovery from drugs such as propofol.

The negative logarithm of the acid dissociation constant, indicating the pH at which half of a drug is ionized. It determines membrane crossing and affects onset of local anesthetics.

A sigmoid graph showing hemoglobin oxygen saturation versus partial pressure of oxygen. It shifts right with increased temperature, carbon dioxide, and 2,3-DPG, reducing affinity and enhancing tissue oxygen delivery.

The volume of air remaining in the lungs after a normal expiration. It equals expiratory reserve volume plus residual volume and helps prevent alveolar collapse during anesthesia.

The pressure gradient driving blood flow to the brain, calculated as mean arterial pressure minus intracranial pressure. Anesthesia goals often include maintaining CPP to prevent cerebral ischemia.

The principle that increased ventricular filling stretches cardiac muscle and increases stroke volume up to a point. Beyond that point, further filling does not improve output and may worsen congestion.

The study of what a drug does to the body, including receptor binding, signal transduction, and resulting physiological effects. It explains why anesthetics cause unconsciousness, amnesia, and immobility.

The study of what the body does to a drug: absorption, distribution, metabolism, and elimination. It determines onset, duration, and offset of anesthetic effects and guides dosing adjustments.

Continuous measurement and display of carbon dioxide in exhaled breath. The waveform confirms tracheal intubation, detects esophageal placement, and monitors ventilation, cardiac output, and metabolism.

A noninvasive technique using light absorption to estimate arterial hemoglobin oxygen saturation and pulse rate. It detects hypoxemia but is affected by poor perfusion, motion, and abnormal hemoglobin.

A neuromuscular monitoring pattern delivering four supramaximal stimuli at 2 Hz to assess the degree of neuromuscular blockade. The ratio of the fourth to first response estimates recovery and guides reversal.

A processed electroencephalogram value ranging from 0 to 100 that estimates depth of hypnosis. Lower values indicate deeper sedation; it is used to reduce awareness risk but has limitations.

Airway pressure applied at end-expiration that keeps alveoli open, improves oxygenation, and reduces atelectasis. Excessive PEEP can impair venous return and cause barotrauma.

An inhaled halogenated agent such as sevoflurane or desflurane that produces unconsciousness and amnesia. Its concentration is titrated using MAC and monitored with an agent analyzer.

A device that converts liquid volatile anesthetic into vapor and mixes it with fresh gas at a controlled concentration. Modern vaporizers are agent-specific and flow- and temperature-compensated.

A supraglottic airway device with an inflatable cuff that seals the pharynx, allowing ventilation without tracheal intubation. It is used for short procedures and rescue ventilation.

A six-category classification (I through VI) used before anesthesia to describe a patient's overall health and systemic disease burden. It predicts perioperative risk and guides preoperative planning.

A bedside airway assessment scoring visible oropharyngeal structures (I through IV) with the mouth open and tongue protruded. Higher classes suggest difficult laryngoscopy, though prediction is imperfect.

The process of explaining a procedure's benefits, risks, alternatives, and the right to refuse, then obtaining patient agreement. It requires decision-making capacity and voluntary choice.

Preoperative fasting recommendations to reduce aspiration risk, typically two hours for clear liquids, six for light meals, and eight for fatty meals. They balance aspiration prevention against dehydration and hypoglycemia.

Medications given before induction to reduce anxiety, prevent aspiration, blunt autonomic responses, or treat comorbidities. Common examples include benzodiazepines, H2 blockers, and beta-blockers.

A validated tool estimating major cardiac complications after noncardiac surgery using six factors, including heart failure, ischemic heart disease, cerebrovascular disease, diabetes, renal impairment, and high-risk surgery.

An induction technique for patients at high aspiration risk that uses a fast-acting induction agent and neuromuscular blocker with minimal ventilation and prompt intubation to secure the airway quickly.

Pressure applied to the cricoid cartilage to compress the esophagus against the cervical spine and reduce passive regurgitation during induction. Its effectiveness is debated and it can worsen laryngoscopy.

Anesthesia maintained solely with intravenous agents, typically propofol and an opioid, without inhaled anesthetics. It avoids volatile agent exposure and is useful for malignant hyperthermia susceptibility.

Paralysis produced by drugs that block acetylcholine at the neuromuscular junction, either depolarizing or nondepolarizing. It facilitates intubation and surgery but requires monitoring and reversal.

A modified gamma-cyclodextrin that encapsulates and inactivates rocuronium or vecuronium, rapidly reversing moderate to deep neuromuscular blockade. It does not reverse succinylcholine or benzylisoquinolinium agents.

A pharmacogenetic hypermetabolic crisis triggered by volatile anesthetics or succinylcholine, causing fever, rigidity, hypercapnia, and rhabdomyolysis. Treatment includes dantrolene, cooling, and supportive care.

A clinical situation in which a trained provider has difficulty with mask ventilation, laryngoscopy, intubation, or airway rescue. Management follows a predefined algorithm with backup devices and early surgical airway planning.

Conscious recall of events during general anesthesia, sometimes with pain or paralysis. Risk is higher with light anesthesia, emergency surgery, and TIVA; monitoring and adequate dosing reduce occurrence.

A recovery area where patients are monitored after anesthesia for airway patency, ventilation, circulation, consciousness, pain, and nausea before discharge or transfer to a ward.

A validated discharge scoring system evaluating activity, respiration, circulation, consciousness, and oxygen saturation. A score of 9 or higher typically indicates readiness for phase I PACU discharge.

Nausea and vomiting occurring within 24 hours after surgery, driven by patient, anesthetic, and surgical factors. Prophylaxis and multimodal antiemetic treatment reduce aspiration and dehydration risk.

Persistent neuromuscular blockade after surgery, often defined as a train-of-four ratio below 0.9. It increases aspiration, hypoxia, and weakness risk; quantitative monitoring and reversal are recommended.

Inhalation of gastric contents or oropharyngeal material into the lower airway, causing chemical pneumonitis, obstruction, or infection. Risk is reduced by fasting, positioning, and rapid airway control.

The legally defined activities and responsibilities a clinician may perform under licensure, certification, and state law. Anesthesia assistants work under supervision with defined limits.