ExAC key terms

A bedside score (classes I–IV) estimating how much of the oropharyngeal structures are visible with the mouth open and tongue protruded; higher classes predict more difficult direct laryngoscopy.

A clinical situation in which a trained provider experiences difficulty with face-mask ventilation, supraglottic airway placement, laryngoscopy, tracheal intubation, or extubation; requires a pre-planned strategy.

A four-grade description of the view of the glottis obtained during direct laryngoscopy, ranging from full visualization of the vocal cords (grade I) to no glottic structures seen (grade IV).

Any backup device or technique (e.g., supraglottic airway, video laryngoscope, surgical airway) used when the primary plan for oxygenation or intubation fails.

A device inserted blindly through the mouth that sits above the larynx and provides ventilation without tracheal intubation; examples include laryngeal mask airways and similar devices.

A manual technique using a self-inflating bag and a tight-fitting mask to deliver positive-pressure breaths to a patient who is not breathing adequately.

A ventilation method in which one provider holds the mask with both hands to seal it while a second provider squeezes the bag, improving delivered tidal volume and reducing leak.

The coordinated administration of a sedative and a neuromuscular blocker in quick succession to facilitate tracheal intubation while minimizing the risk of aspiration and gastric insufflation.

Application of backward pressure on the cricoid cartilage to compress the esophagus and reduce passive regurgitation during induction of anesthesia; its routine use is debated.

The partial pressure of carbon dioxide measured at the end of exhalation, used to confirm tracheal tube placement and to monitor ventilation and cardiac output trends.

Continuous graphical display of carbon dioxide concentration in inspired and expired gas over time, used to verify airway placement and detect apnea, obstruction, or hypoventilation.

A noninvasive method that estimates arterial oxygen saturation by measuring light absorption through pulsatile tissue; it lags behind actual changes in ventilation and oxygenation.

An abnormally low level of oxygen in arterial blood, commonly indicated by a low pulse oximetry reading or a low arterial partial pressure of oxygen on blood gas analysis.

A pressure maintained in the airways at the end of exhalation during mechanical ventilation, which helps keep alveoli open and improves oxygenation in many patients.

The volume of air moved into or out of the lungs during a single normal breath; in ventilated patients it is usually set according to predicted body weight.

The total volume of gas exhaled per minute, calculated as tidal volume multiplied by respiratory rate; it is a key determinant of carbon dioxide removal.

The average pressure in a patient's arteries during one cardiac cycle, estimated as diastolic pressure plus one-third of the pulse pressure; it reflects organ perfusion.

Abnormally low blood pressure that may impair perfusion of vital organs; in adults it is often defined as systolic pressure below 90 mmHg or a fall of more than 40 mmHg from baseline.

A life-threatening state of inadequate tissue perfusion that can result from blood loss, pump failure, obstruction, or widespread vasodilation, leading to cellular dysfunction if untreated.

A regular rhythm originating from the sinus node with a heart rate below the normal range, commonly under 60 beats per minute in adults; may be physiologic or a sign of drug effect or ischemia.

An anticholinergic drug that blocks vagal effects on the heart, increasing heart rate; it is used for symptomatic bradycardia but is less effective in high-degree heart block.

A 3-to-15 point score assessing eye opening, verbal response, and motor response; lower scores indicate greater impairment of consciousness and help guide airway and monitoring decisions.

A 10-point scale from -5 (unarousable) to +4 (combative) used to quantify level of sedation and agitation in critically ill or sedated patients.

Any standardized tool used to rate a patient's level of consciousness and responsiveness during procedural sedation, helping titrate drugs and detect oversedation.

A processed electroencephalogram-derived number from 0 to 100 that estimates depth of hypnosis during anesthesia, with lower values indicating deeper sedation.

Paralysis of skeletal muscle produced by drugs that interrupt transmission at the neuromuscular junction, used to facilitate intubation or ventilation; sedation must be maintained concurrently.

A drug that counteracts the effects of another drug, such as an opioid antagonist or a neuromuscular blockade reversal agent, restoring normal function more quickly.

An opioid receptor antagonist that rapidly reverses opioid-induced respiratory depression and sedation; repeated doses or an infusion may be needed because its duration can be shorter than that of the opioid.

A benzodiazepine receptor antagonist used to reverse benzodiazepine-induced sedation and respiratory depression; it may precipitate seizures in benzodiazepine-dependent patients.

A selective relaxant binding agent that rapidly encapsulates and inactivates aminosteroid neuromuscular blockers such as rocuronium, reversing deep blockade.

An acetylcholinesterase inhibitor that increases acetylcholine at the neuromuscular junction to reverse non-depolarizing neuromuscular blockade; it is often paired with an antimuscarinic drug.

A six-category classification (I–VI) assigned before anesthesia that reflects a patient's overall health and severity of systemic disease, used for risk communication and resource planning.

The process of grouping patients by likelihood of complications using history, examination, and test results so that monitoring and interventions can be matched to their needs.

Any additional medical condition that coexists with the primary problem being treated, which can increase perioperative risk and influence airway and medication choices.

An eight-item screening tool that estimates the risk of obstructive sleep apnea using snoring, tiredness, observed apnea, blood pressure, body mass index, age, neck circumference, and gender.

A disorder in which the upper airway repeatedly collapses during sleep, causing pauses in breathing and oxygen desaturation; it increases difficulty with airway management and sedation.