ABA Anesthesiology key terms

The alveolar concentration of an inhaled anesthetic at which 50% of patients do not move in response to a standardized surgical stimulus; used to compare potency and guide dosing.

The time needed for plasma concentration to fall by half after stopping an infusion, determined by how long the infusion ran; it predicts recovery from drugs distributed slowly to tissues.

The estimated concentration of a drug at its site of action in the brain, modeled from plasma kinetics; it lags plasma concentration and better predicts onset of anesthetic effect.

The apparent volume relating the amount of drug in the body to its plasma concentration; a large value indicates extensive tissue uptake and can prolong elimination.

The volume of gas remaining in the lungs after a normal expiration; it acts as an oxygen reservoir and is reduced by obesity, supine position, and general anesthesia.

The rate at which oxygen is transported to tissues, calculated as cardiac output times arterial oxygen content; it falls with anemia, low output, or hypoxemia.

A technique for rapid tracheal intubation using a predetermined dose of induction agent and neuromuscular blocker with minimal delay, used when aspiration risk or urgent airway control is present.

An infusion pump system that adjusts drug delivery to reach and maintain a chosen target plasma or effect-site concentration, using pharmacokinetic models rather than fixed rates.

The ratio of the fourth to the first evoked muscle response during four supramaximal nerve stimuli; values below 0.9 indicate residual neuromuscular blockade and increased postoperative risk.

Ventilation of only one lung, usually achieved with a double-lumen tube or bronchial blocker, to isolate and collapse the operative lung during thoracic surgery.

A device inserted blindly through the mouth that seals above the larynx and permits ventilation without tracheal intubation; it does not protect against aspiration.

The continuous display of expired carbon dioxide over time; its shape and height reveal ventilation, airway obstruction, esophageal intubation, and low cardiac output.

A six-level classification of preoperative health, from normal (I) to brain-dead organ donor (VI), used to communicate risk but not to predict outcomes alone.

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

A screening questionnaire for obstructive sleep apnea scored from snoring, tiredness, observed apnea, blood pressure, body mass index, age, neck circumference, and gender.

A rise in troponin after noncardiac surgery above a prognostic threshold, without necessarily meeting criteria for myocardial infarction; it predicts short- and long-term mortality.

A multidimensional age-related syndrome of reduced physiologic reserve and increased vulnerability to stress, associated with postoperative complications, functional decline, and death.

An acute fluctuating disturbance of attention and cognition occurring days after surgery, often triggered by inflammation, pain, medications, and sensory deprivation, and linked to longer hospital stays.

A consensus definition describing sepsis as life-threatening organ dysfunction caused by a dysregulated response to infection, identified by an increase in the Sequential Organ Failure Assessment score.

Criteria defining acute respiratory distress syndrome by timing within one week, bilateral opacities, noncardiogenic edema, and hypoxemia graded by the ratio of arterial oxygen to inspired oxygen.

Staging criteria for acute kidney injury based on a rise in serum creatinine or a fall in urine output over defined intervals, guiding severity classification and management.

A ventilation strategy using low tidal volumes around six milliliters per kilogram of predicted body weight, limited plateau pressures, and adequate positive end-expiratory pressure to reduce ventilator-induced injury.

A period of unassisted or minimally supported breathing used to assess whether a patient can be safely removed from mechanical ventilation, often combined with a sedation interruption.

Deliberate control of body temperature to a chosen range after cardiac arrest or brain injury, aiming to reduce secondary neurologic damage while avoiding shivering and metabolic complications.

The difference between measured serum sodium and the sum of chloride and bicarbonate; an elevated value suggests unmeasured acids such as ketones, lactate, or toxins.

A rare but potentially fatal syndrome of neurologic and cardiovascular toxicity after local anesthetic exposure, often from accidental intravascular injection or excessive dose.

Intravenous administration of a lipid emulsion as rescue treatment for local anesthetic systemic toxicity, thought to create a lipid sink that removes drug from cardiac tissue.

A postural headache that worsens upright and improves lying flat after dural puncture, caused by cerebrospinal fluid leakage; conservative therapy, caffeine, or an epidural blood patch may be used.

A strategy combining analgesics with different mechanisms and nonpharmacologic measures to improve pain relief and reduce opioid dose and side effects.

A paradoxical increase in pain sensitivity during opioid therapy, distinct from tolerance and withdrawal, attributed to central sensitization and neuroplastic changes.

An ultrasound-guided injection of local anesthetic between the transversus abdominis and internal oblique muscles to provide somatic analgesia for abdominal wall incisions.

A structured team investigation that traces an adverse event back to underlying system failures and contributing factors, aiming to design preventive changes rather than assign blame.

A safety culture that encourages reporting of errors and near misses while distinguishing human error from reckless behavior, balancing accountability with learning.

A teamwork practice in which a message is acknowledged and confirmed by the receiver, reducing misunderstandings during high-stakes handoffs and emergency situations.

A standardized list used before induction, before incision, and before leaving the operating room to confirm patient identity, procedure, equipment, and team concerns.

A structured handoff mnemonic covering illness severity, patient summary, action items, situation awareness, and synthesis, designed to reduce communication failures during care transitions.

An unexpected patient safety incident that causes death, permanent harm, or severe temporary harm and requires immediate investigation and response.