Critical care terminology and unit conventions
Educational work by a pre-medical student — not medical advice. Not a clinical protocol, prescription, or patient handout, and not for patient care. See DISCLAIMER.
Revised 27 October 2026. This concise glossary replaces the earlier expanded list where shorthand could be mistaken for a diagnostic or treatment rule.
| Term | Educational meaning and limit |
|---|---|
| CO / CI | Cardiac output / output indexed to body surface area; measurement method matters |
| MAP / RAP / CVP | Mean arterial / right atrial / central venous pressure; filling pressures are not stand-alone fluid tests |
| SVR | Systemic vascular resistance; specify units and the pressure/flow calculation |
| EF | Ejection fraction; loading-dependent and not a complete measure of perfusion or intrinsic contractility |
| CaO2 / DO2 | Arterial oxygen content / systemic oxygen delivery; see the linked formulas |
| ScvO2 / SvO2 | Central / mixed venous oxygen saturation; sampling locations differ and values are not interchangeable |
| IVC | Inferior vena cava; its appearance depends on ventilation and cardiovascular context |
| AKI / RRT / CRRT | Acute kidney injury / renal replacement therapy / continuous therapy; none follows automatically from a creatinine value |
| ARDS / P:F | A clinical syndrome / arterial oxygen tension divided by inspired oxygen fraction; all diagnostic criteria matter |
| PBW | Predicted body weight, distinct from actual body weight |
| PEEP / Pplat / DP | End-expiratory / plateau / driving pressure; interpret measurement conditions and total PEEP |
| NIV / HFNC / SBT | Non-invasive ventilation / high-flow nasal cannula / spontaneous breathing trial; they refer to different support contexts |
| ICP / CPP | Intracranial / cerebral perfusion pressure; the simplified relationship is not a universal target |
| VA / VV ECMO | Venoarterial / venovenous extracorporeal support; mode and configuration determine interpretation |
| LVAD / PI | Left ventricular assist device / pulsatility index; displayed values are device/context dependent |
| RASS | Richmond Agitation-Sedation Scale; a score is not an analgesia or amnesia guarantee |
| DNR / DNI | Limits on resuscitation / intubation as documented; neither alone means comfort-only care |
See physiology formulas, source guide and case exercises. No copyrighted clinical scale items or questionnaire forms are reproduced.