Table 1 Summary of the recommendations
Blood sampling |
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1. Patients whose severity of illness justifies invasive vascular monitoring |
   a. All blood samples should be drawn from an arterial line |
   b. If an arterial line is temporarily or permanently unavailable, sample from a venous line |
   c. Capillary (needle stick) samples are inaccurate and should not be used |
2. Patients whose severity of illness does not justify invasive vascular monitoring |
   a. Capillary (needle stick) samples may be used |
3. Clinical research papers should report the number and percentage of blood samples obtained from arterial catheters, central and peripheral venous catheters and capillary (needle stick) samples |
Choice of blood glucose analyzer in clinical research in critical care units |
   a. Samples taken from arterial or central venous catheters should be analyzed in a central laboratory or blood gas analyzer; a blood gas analyzer should be the default analyzer |
   b. Only when capillary samples are taken from patients without invasive vascular monitoring is analysis using a glucose meter acceptable |
   c. Clinical research papers should report the number and percentage of samples analyzed using central laboratory or blood gas analyzers or glucose meters. In all cases, the make and model of the analyzer used should be reported along with routine calibration and quality assurance measures |
Reporting glycemic control - trials or observational studies should report |
1. Central tendency - for blood glucose concentration measurements from a population of patients, the median and interquartile range of individual patient means should be reported |
2. Dispersion - calculate the standard deviation of blood glucose concentration for each patient then report the median and interquartile range of standard deviations for the population |
3. Hypoglycemia - as a minimum, investigators should report the number and percentage of patients experiencing at least one episode of severe and moderate hypoglycemia (blood glucose concentration ?2.2 (?40 mg/dl) and 2.3 to 3.9 mmol/l (41 to 70 mg/dl) respectively). Report separately the number and percentage of patients experiencing hypoglycemia related to insulin treatment (iatrogenic) and unrelated to insulin treatment (spontaneous) |
For severe hypoglycemia, report duration of hypoglycemia, associated symptoms, amount of glucose administered, and next blood glucose concentration |
Appropriate standards for intermittent measurement of blood glucose in the ICU |
Blood sampling |
1. Patients whose severity of illness justifies invasive vascular monitoring |
   a. All blood samples should be drawn from an arterial line |
   b. If an arterial line is temporarily or permanently unavailable, sample from a venous line |
   c. Capillary (needle stick) samples are inaccurate and should not be used |
2. Patients whose severity of illness does not justify invasive vascular monitoring |
   a. Capillary (needle stick) samples may be used |
Choice of blood glucose analyzer in clinical practice in critical care units |
1. Patients whose severity of illness justifies invasive vascular monitoring |
   a. Samples taken from arterial or central venous catheters should be analyzed in a central laboratory or blood gas analyzer; a blood gas analyzer should be the default analyzer, central laboratory measurements should only be used if results can be obtained without delay |
2. Patients whose severity of illness does not justify invasive vascular monitoring |
   a. Only when capillary samples are taken from patients considered well to need invasive vascular monitoring is analysis using a glucose meter acceptable |
Accuracy of blood glucose analyzers used in clinical practice in critical care units |
1. Patients whose severity of illness justifies invasive vascular monitoring |
   a. Central laboratory analyzers and blood gas analyzers in the ICU should perform to currently acceptable international standards (for example, ±0.4 mmol/l (or ±8% above 5 mmol/l)) |
2. Patients whose severity of illness does not justify invasive vascular monitoring |
   a. The minimum standard for glucose meters to be used in critically ill patients should be that 98% of readings are within 12.5% of a reference standard (or within 0.55 mmol/l for readings <5.5 mmol/l). The remaining 2% of readings should be within 20% of a reference standard |
Continuous and automated intermittent blood glucose monitoring |
Assessment of glycemic control when continuous or automated intermittent blood glucose monitoring used |
1. Currently there are few data to guide the choice of appropriate metrics for reporting glycemic control when continuous or automated intermittent blood glucose monitoring is used. There is a need to define measures that are associated with important patient-centered outcomes such as mortality and major morbidity |
Comparing glycemic control with continuous versus intermittent measurement of blood glucose |
1. Comparison of the glycemic control achieved with continuous versus intermittent monitoring must be evaluated in randomized controlled trials with both groups of patients having a continuous monitor but the output from the continuous monitor masked in the control group where blood glucose is managed by intermittent monitoring |
What are desirable performance standards for continuous glucose monitoring systems? |
1. Set-up, calibration and integration with standard ICU care |
   a. <20 minutes to set by a nurse, technician, or physician |
   b. <10 minutes required for initial and subsequent calibration |
   c. <20 minutes required for sensor insertion |
   d. Calibration against a reference standard to maintain point accuracy is required no more frequently than every 8 hours and preferably no more than twice per 24 hours |
   e. CGM requires few nursing interventions per 24 hours to produce a near-continuous datastream |
   f. CGM sensor inserted into an arterial or central venous catheter should not adversely affect blood sampling or monitoring of cardiovascular system or increase the frequency with which such monitoring lines occlued |
   g. Incidence of infection, hematoma, tissue ischemia, and/or thromboembolism should not exceed that which occurs in usual clinical practice in the absence of a CGM |
2. Reliability |
   a. CGM should continuously measure glucose and display in real time >95% of the time for the duration of time specified in the product label (2 to 7 days) |
   b. Skips in data acquisition should not exceed 30 minutes at a time |
   c. The CGM should have an internal mechanism that prevents the display or reporting of erroneous or spurious data |
3. Point accuracy - this should be the same as for intermittent monitors if the CGM is being used alone to guide clinical management and administration of insulin |
   a. 98% of readings are within 12.5% of a reference standard (or within 0.55 mmol/l for readings <5.5 mmol/l). The remaining 2% of readings should be within 20% of a reference standard |
   b. CGM sensors inserted in arterial and central venous catheters may transiently indicate false low readings when those catheters are flushed with saline or other glucose-free solutions. The CGM should alert the treating clinicians that rapid reductions in the measured blood glucose concentration may be due to flushing of the arterial or central venous catheter |
   c. CGM sensors inserted in peripheral and central veins may transiently indicate false high readings if venous blood in those veins is contaminated with glucose-containing solutions. The CGM should alert the treating clinicians to rapid increases in the measured blood glucose concentration that may be due to contamination by glucose-containing solutions |
4. Rate or trend accuracy - trend metrics have not been tested sufficiently to provide definitive guidance or recommendations; this is an area for future research |
5. Alarms and alerts for hypoglycemia and hyperglycemia alerts |
   a. Real-time blood glucose concentration and trend data should be displayed at the bedside; with visual and audible alerts and alarms for hypoglycemia, hyperglycemia, and rapid rates of change |
   b. The CGM data should be sufficiently frequent, reliable, and accurate for alarm algorithms to detect and/or predict hypoglycemia and hyperglycemia with high sensitivity and specificity |