Continuous haemofiltration in the intensive care unit

Table 1 Potential indications for CRRT in the ICU

• Nonobstructive oliguria (urine output <200 ml/12 h) or anuria
• Severe acidaemia (pH <7.1) due to metabolic acidosis
• Azotaemia ([urea] >30 mmol/l)
• Hyperkalaemia ([K⁺] >6.5 mmol/l or rapidly rising [K⁺])^*
• Suspected uraemic organ involvement (pericarditis/encephalopathy/
neuropathy/myopathy)
• Progressive severe dysnatraemia ([Na⁺] >160 or <115 mmol/l)
• Hyperthermia (core temperature >39.5°C)
• Clinically significant organ oedema (especially lung)
• Drug overdose with dialyzable toxin
• Coagulopathy requiring large amounts of blood products in patient
with or at risk of pulmonary oedema/ARDS^†

Any one of these indications constitutes sufficient grounds for considering the initiation of CRRT. Two of the above criteria make CRRT highly desirable. Combined disorders suggest the initiation of CRRT even before some of the above-mentioned `limits' have been reached. ^*IHD removes potassium more efficiently than CRRT. However, if CRRT is started early enough, hyperkalaemia is easily controlled. ^†For example, a fulminant liver failure patient with adult respiratory distress syndrome (ARDS), an international normalized ratio >3 and spontaneous epistaxis. Unless volume is rapidly removed, as fresh frozen plasma is rapidly given, the patient is very likely to develop pulmonary oedema.

ISSN: 1364-8535