Intensive Care Medicine/definitions


The following is a tabular form of definitions for Intensive Care Illnesses. The approved or widely-accepted abbreviations or acronyms could be included in the 'short form' column .

Name Short form Definition
Acute Respiratory Distress Syndrome ARDS (Respiratory failure) within one week of a known clinical insult or new or worsening respiratory symptoms (with) bilateral (pulmonary) opacities (on Chest X-ray or Computerised tomographic (CT) Scan) - not fully explained by effusions, lobar/lung collapse or nodules, not fully explained by Cardiac failure or fluid overload* (with) PaO2/FiO2 ≤ 300mmHg with PEEP or CPAP≥5CmH2O^. *Need objective assessment (ex.Echocardiography) to exclude hydrostatic oedema if no risk factor present.†Mild >200≤300mmHg, Moderate >100≤200mmHg, Severe ≤100mmHg. If the altitude is higher than 1000m (from Mean Sea Level), a Correction factor should be calculated as follows:[PaO2/FiO2X(Barometric Pressure/760)].^This may be delivered non-invasively in Mild acute respiratory distress group. [1]
Intensive Care Medicine Intensive and Critical Care Medicine is a distinct branch of medicine specifically organized for the management of patients with immediate life-threatening pathophysiological conditions. It requires the grouping of special facilities and specially trained staff in pursuit of this aim. The terms Intensive Care Medicine and Critical Care Medicine are considered synonymous.[2]

2016 definition[3]:

  • Sepsis is defined as life-threatening organ dysfunction due to a dysregulated host response to infection.
The suggested method to assess for organ dysfunction is Sequential (Sepsis-Related) Organ Failure Assessment (SOFA).
The qSOFA (quick SOFA) assessment directs physicians to look for these warning signs in patients:
   An alteration in mental status 
   A decrease in systolic blood pressure of less than 100 mm Hg
   A respiration rate greater than 22 breaths/min
If a patient has any two or more components of qSOFA, the patient should be examined for organ failure.
  • Septic shock is defined as a subset of sepsis in which particularly profound circulatory, cellular, and metabolic abnormalities substantially increase mortality. The following are clinical criteria that clinicians should use in diagnosing patients with septic shock:
   Persisting hypotension requiring vasopressors to maintain MAP ≥65 mmHg
   Blood lactate >2 mmol/L despite adequate volume resuscitation

2012 definition:

  • Sepsis is defined as the presence (probable or documented) of infection together with systemic manifestations of infection.
  • Severe sepsis is defined as sepsis plus sepsis-induced organ dysfunction or tissue hypoperfusion.
  • Sepsis-induced hypotension is defined as a systolic blood pressure (SBP) < 90 mm Hg or mean arterial pressure (MAP) < 70 mmHg or a SBP decrease > 40 mm Hg or less than two standard deviations below normal for age in the absence of other causes of hypotension.
  • Septic shock is defined as sepsis-induced hypotension persisting despite adequate fluid resuscitation. Sepsis-induced tissue hypoperfusion is defined as infection-induced hypotension, elevated lactate, or oliguria.[4]
Status Epilepticus SE Status epilepticus is a condition resulting either from the failure of the mechanisms responsible for seizure termination or from the initiation of mechanisms, which lead to abnormally, prolonged seizures (after time point t1). It is a condition, which can have long-term consequences (after time point t2), including neuronal death, neuronal injury, and alteration of neuronal networks, depending on the type and duration of seizures. In the case of convulsive (tonic–clonic) SE, t1 is 5 min and t2 is 30 min.This definition is conceptual, with two operational dimensions: the first is the length of the seizure and the time point (t1) beyond which the seizure should be regarded as “continuous seizure activity.” The second time point (t2) is the time of ongoing seizure activity after which there is a risk of long-term consequences. In the case of convulsive (tonic–clonic) SE, both time points (t1 at 5 min and t2 at 30 min) are based on animal experiments and clinical research. This evidence is incomplete, and there is furthermore considerable variation, so these time points should be considered as the best estimates currently available. Data are not yet available for other forms of SE.[5]
Ventilator associated Pneumonia VAP Ventilator-associated pneumonia (VAP) is defined as pneumonia that occurs 48-72 hours or thereafter following endotracheal intubation, characterized by the presence of a new or progressive infiltrate, signs of systemic infection (fever, altered white blood cell count), changes in sputum characteristics, and detection of a causative agent. [6]
Acute Renal Failure RIFLE criteria
  • Class - Glomerular filtration rate criteria - Urine output criteria
  • Risk Serum creatinine × 1.5 Urine output < 0.5 ml/kg/hour × 6 hours
  • Injury Serum creatinine × 2 Urine output < 0.5 ml/kg/hour × 12 hours
  • Failure Serum creatinine × 3, or serum creatinine ≥4 mg/dl with an acute rise > 0.5 mg/dl Urine output < 0.3 ml/kg/hour × 24 hours, or anuria× 12 hours
  • Loss Persistent acute renal failure = complete loss of kidney function > 4 weeks
  • End-stage kidney disease End-stage kidney disease > 3 months

For conversion of creatinine expressed in conventional units to SI units, multiply by 88.4. RIFLE class is determined based on the worst of either glomerular filtration criteria or urine output criteria. Glomerular filtration criteria are calculated as an increase of serum creatinine above the baseline serum creatinine level. Acute kidney injury should be both abrupt (within 1–7 days) and sustained (more than 24 hours). When the baseline serum creatinine is not known and patients are without a history of chronic kidney insufficiency, it is recommend to calculate a baseline serum creatinine using the Modification of Diet in Renal Disease equation for assessment of kidney function, assuming a glomerular filtration rate of 75 ml/min/1.73 m2. When the baseline serum creatinine is elevated, an abrupt rise of atleast 0.5 mg/dl to more than 4 mg/dl is all that is required to achieve class Failure. [7]

Central line associated blood stream infection CLABSI A laboratory-confirmed bloodstream infection (LCBI) where central line (CL) or umbilical catheter (UC) was in place for >2 calendar days on the date of event, with day of device placement being Day 1, AND the line was also in place on the date of event or the day before.[8]
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  1. The ARDS Definition Task Force. Acute respiratory distress syndrome: the Berlin definition. JAMA 2012;307:2526–2533 Read More:
  5. Trinka, E., Cock, H., Hesdorffer, D., Rossetti, A. O., Scheffer, I. E., Shinnar, S., Shorvon, S. and Lowenstein, D. H. (2015), A definition and classification of status epilepticus – Report of the ILAE Task Force on Classification of Status Epilepticus. Epilepsia, 56: 1515–1523. doi: 10.1111/epi.13121 |
  6. Critical Care 2014, 18:208 doi:10.1186/cc13775 |
  7. Critical Care 2006, 10:R73 doi:10.1186/cc4915 |