Bedside Blood Glucose Monitoring in Critically Ill Patients: Comparison Between Arterial and Capillary Glucose

Background: Critically ill patients are at high risk of hypoglycemia and are particularly vulnerable to unrecognized hypoglycemia. Close blood glucose monitoring is therefore crucial. There are several options to conduct frequent blood glucose measurement and a number of conditions in intensive care unit patients may affect the accuracy of blood glucose measurement. The aim of the study was to compare the accuracy of capillary glucose by bedside glucometer with arterial samples by bedside glucometer and arterial samples by blood gas analyzer in critically ill patients through a prospective case-control study. Materials and Methods: Arterial and capillary samples from 60 patients were taken simultaneously and were tested immediately at the bedside. Results of the paired measurements were compared and expressed as a correlation coefficient. Resuls: Capillary glucose in the study group and control group were 9.73 +/- 2.28 mmol/L and 8.9 +/- 1.86 mmol/L, respectively; mean arterial glucose measured by glucometer in the study group and control group were 9.25 +/- 2.05 mmol/L and 8.4 +/- 1.89 mmol/L, respectively; and mean arterial glucose measured by blood gas analyzer in the study group and control group were 8.41 +/- 1.9 mmol/L and 8.24 +/- 1.5 mmol/L, respectively. Correlation between capillary values and arterial values measured by glucometer was less in the study group (r = 0.936, P < 0.001 and r = 0.973, P < 0.001). Correlation between capillary values measured by glucometer and arterial values measured by blood gas analyzer was also less in the study group (r = 0.897, P = 0.001 and r = 0.964, P < 0.001). Conclusions: Capillary blood glucose monitoring is reliable only in a selected group of critically ill patients.