AS7.1-5 | Intensive Care Management — Glossary

Acute Physiology and Chronic Health Evaluation II — a severity-of-illness score using 12 acute physiology variables, age, and chronic health points to predict ICU mortality risk; higher scores correlate with higher predicted mortality.

Analysis of arterial blood for pH, PaO2, PaCO2, HCO3, base excess, and lactate; the definitive assessment of respiratory and metabolic status in ICU patients; performed every 4-8 hours in ventilated patients.

An indwelling arterial catheter (usually radial or femoral) providing continuous beat-to-beat blood pressure monitoring and a port for arterial blood gas sampling.

A multi-lumen catheter placed in a large central vein (internal jugular, subclavian, or femoral) for CVP monitoring, vasopressor administration, concentrated electrolyte infusion, and high-volume fluid resuscitation.

CPP = MAP minus ICP; the driving pressure for cerebral blood flow; target CPP 60-70 mmHg in severe TBI to prevent secondary ischaemic injury.

Central-Line-Associated Bloodstream Infection; bloodstream infection attributed to an indwelling central venous catheter, prevented by the central-line bundle (aseptic insertion, chlorhexidine skin prep, daily necessity review, prompt removal).

A slow, continuous form of extracorporeal renal replacement (e.g. CVVHDF) preferred in haemodynamically unstable ICU patients because gradual solute and volume removal avoids hypotensive episodes associated with intermittent haemodialysis.

The triad of hypertension, bradycardia, and irregular breathing seen with severely raised intracranial pressure compressing the brainstem; a pre-terminal sign of impending herniation requiring emergency intervention.

The structured approach to high-pressure alarms in ventilated patients: D = Displacement of ETT, O = Obstruction (secretions, kinking), P = Pneumothorax, E = Equipment failure; each is excluded or confirmed systematically.

A cuffed tube placed through the mouth or nose past the vocal cords into the trachea to secure the airway, deliver mechanical ventilation, and prevent aspiration.

The concentration of CO2 in exhaled gas at the end of expiration measured by capnography; normally 35-45 mmHg; confirms ETT position (waveform disappears with oesophageal intubation or cardiac arrest) and tracks ventilation.

The proportion of oxygen in the inspired gas mixture, expressed as a decimal (0.21 = room air, 1.0 = 100% oxygen); titrated to achieve SpO2 94-98%, targeting FiO2 0.40-0.60 to reduce oxygen toxicity.

A standardised neurological assessment scoring eye opening (E1-4), verbal response (V1-5), and motor response (M1-6), giving a total of 3-15; a GCS of 8 or below triggers airway protection consideration.

Unplanned return to the ICU within 48-72 hours of discharge; associated with 2-3 times higher in-hospital mortality than index admissions and used as a quality indicator of premature discharge.

A weight estimate based on height and sex used to calculate tidal volume for ventilation; for males: 50 + 0.91 x (height in cm - 152.4); for females: 45.5 + 0.91 x (height in cm - 152.4); differs from actual body weight in obese patients.

A geographically distinct hospital area providing continuous monitoring and organ support for patients with actual or threatened life-threatening single or multi-organ failure.

A physician with dedicated training in intensive care medicine (typically anaesthesiologist or pulmonologist) who leads ICU clinical care, daily ward rounds, and family communication.

A tertiary referral ICU capable of all forms of organ support including CRRT, ECMO, IABP, and complex specialist input; the highest level of critical-care capability.

The average arterial pressure across one cardiac cycle; calculated approximately as DBP + one-third of pulse pressure; a MAP of 65 mmHg or above is the standard resuscitation target in septic shock.

Positive-pressure respiratory support delivered via an endotracheal tube or tracheostomy; modes include volume-controlled (VC) and pressure-controlled (PC) ventilation, with lung-protective settings for ARDS (VT 6 mL/kg IBW, Pplat 30 cmH2O or less).

The number of patients assigned per ICU nurse; ISCCM recommends a minimum 1:2 ratio with a target of 1:1 for ventilated or haemodynamically unstable patients.

PaO2 divided by FiO2 (as a decimal); used to classify ARDS severity: mild 200-300, moderate 100-200, severe below 100 mmHg.

A ventilator setting that maintains positive airway pressure at end-expiration, preventing alveolar collapse (de-recruitment) and improving oxygenation in ARDS and other respiratory failure states.

A deliberate strategy in severe ARDS allowing PaCO2 to rise above normal (45-80 mmHg) in exchange for using lower tidal volumes (6 mL/kg IBW) to limit lung overdistension; acceptable if pH remains above 7.20.

A partial-support mode where the patient triggers every breath and the ventilator provides a set inspiratory pressure boost; used for weaning off mechanical ventilation.

A ventilator mode that delivers flow until a set inspiratory pressure is reached; tidal volume varies with lung compliance, requiring close VT monitoring.

Sequential Organ Failure Assessment score (0-24) quantifying dysfunction across six organ systems (respiratory, coagulation, hepatic, cardiovascular, neurological, renal); a rising SOFA score indicates worsening organ failure and higher mortality risk.

A 30-120 minute trial during which a ventilated patient breathes on minimal support (T-piece or low-level PSV) to assess readiness for extubation; failure criteria include SpO2 below 90%, RR above 35, haemodynamic instability.

The volume of air delivered per breath; in lung-protective ventilation for ARDS, VT is set at 6 mL/kg ideal body weight to avoid overdistension and ventilator-induced lung injury.

A surgical opening in the anterior trachea through which a tracheostomy tube is placed; considered after 10-14 days of mechanical ventilation to improve patient comfort, reduce sedation requirements, facilitate weaning, and simplify airway nursing.

A patient with a Glasgow Coma Scale score of 8 or below who cannot reliably protect their airway; requires endotracheal intubation for airway security in the ICU.

Pneumonia developing 48 or more hours after endotracheal intubation; prevented by the VAP care bundle (head-of-bed elevation, daily sedation holiday, subglottic drainage, oral chlorhexidine, ulcer prophylaxis, DVT prophylaxis).

A vasoconstrictor drug (e.g. norepinephrine, vasopressin) used to raise systemic vascular resistance and mean arterial pressure in distributive or vasodilatory shock; must be administered via central venous access.

Lung injury caused by mechanical ventilation through overdistension (volutrauma), excessive pressure (barotrauma), repetitive alveolar collapse-and-reopening (atelectrauma), or oxygen toxicity; prevented by lung-protective strategy.

A ventilator mode that delivers a fixed tidal volume per breath regardless of the pressure required; guarantees minute ventilation but peak airway pressure rises if compliance falls.