Bibliographic information
Guideline—
Year of Publication—
Issuing Institution—
Recommendation
New
WHO suggests for patients with suspected or confirmed filovirus disease and clinical signs of shock or circulatory impairment, the serial measurement of lactate as part of the assessment of perfusion to guide further intravenous fluid management.
Recommended in favor
Conditional
Certainty of evidence
Low
Notes and Remarks
- This recommendation applies to children and adults, including pregnant women.
- Lactate is a marker of poor perfusion and when elevated is associated with poor prognosis.
- The assessment of perfusion also includes other clinical markers such as blood pressure, heart rate, urine output, mental status and capillary refill time.
- Reduction of lactate over time can be used to infer the effectiveness of fluid replacement. However, normalization of lactate should not be the target.
- There are situations where elevated lactate levels are not associated with poor perfusion and these include: advanced liver disease when lactate metabolism is impaired, excessive muscles activity, focal or regional areas of tissue ischaemia, and some drugs (for example metformin). Persistent raised lactate should prompt a search for other coexistent pathologies.
- Lactate can be measured in arterial, venous or capillary blood. The choice of sample type should follow local practice and be used consistently, especially when comparing lactate levels over time. Arterial puncture is the reference standard for accuracy, but it is not encouraged due to bleeding risk in filovirus disease. Practical info
- Minimize the use of tourniquet and direct pressure when collecting lactate sample to minimize artefactual high levels.
- Interpretation should use all clinical information available, including blood pressure, urine output, conscious level and skin changes.
- Consider other causes of hyperlactaemia for example seizure, drugs (notably metformin, ethylene glycol), malignancy, and alcohol use disorder (59).
- Trends in lactate are important, and should be interpreted in the context of the patient’s clinical condition and medical interventions. Take note particularly of the initiation of vasopressors (increasing adrenergic drive and increased lactate levels) and recent fluid therapy. If the trend is not improving, or unexpectedly increasing, consider potential underlying factors, including focal tissue ischaemia (for example bowel obstruction). There was no strict protocolization of how information on lactate should be used across the studies. Cut points of 2 mmol/L and 4 mmol/L have been frequently used to describe the upper limit of normal and the threshold of lactate acidosis respectively. Lactate can be used for identifying patients at high risk of adverse outcome. The choice of arterial, venous or capillary measurement may be driven by available resources. These are not necessarily directly comparable, and therefore for serial measures in a single patient, the same test type should be used.