From the Research
I recommend checking lactic acid levels at least every 6 hours in critically ill patients, as lactate clearance at this discrete time point seems to be a more reliable prognostic index than initial lactate value. This is based on the study by 1, which found that a decrement in lactate clearance of at least 10% for the first 6 hours, 24 hours, and 48 hours of treatment was more dominant among survivors than non-survivors. The study also found that 6-hour, 24-hour, and 48-hour lactate clearance and vasopressor use were significantly associated with mortality after adjusting for confounding variables.
Some key points to consider when checking lactic acid levels include:
- The timing of lactate level checks, with more frequent checks (e.g. every 6 hours) potentially providing more accurate prognostic information than less frequent checks
- The use of vasopressors, which has been shown to be associated with higher mortality rates in patients with lactic acidosis
- The initial lactate level, which can provide some prognostic information, but is less reliable than lactate clearance at discrete time points
It's also worth noting that other studies, such as those by 2, 3, and 4, have found similar associations between lactate levels, vasopressor use, and mortality in patients with cardiac arrest or sepsis. However, the study by 1 provides the most direct evidence for the importance of checking lactic acid levels at least every 6 hours in critically ill patients.
In terms of the specific timing of lactic acid level checks, the study by 1 suggests that checks at 6,24, and 48 hours after initial lactate measurement may be particularly useful for predicting mortality. However, the optimal timing of lactate level checks may vary depending on the individual patient and the specific clinical context.