Accuracy of AccuChek glucose measurement in intensive care patients.

OBJECTIVE: To evaluate the accuracy of the AccuChek Inform point-of-care glucose measurement device as compared with central laboratory glucose measurement. DESIGN: Prospective, observational study. SETTING: A ten-bed mixed closed format intensive care unit ina 500-bed general hospital. The unit has a computerized insulin protocol aiming for 81 to 135 mg/dL. PATIENTS: All intensive care unit patients were eligible. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Paired samples (AccuChek glucose in whole blood calibrated to give whole blood results and central laboratory glucose in serum) were taken simultaneously. In 32 critically ill patients, we obtained the following information: mean +/- standard deviation age 71.6 +/- 11.9 yrs; mean Acute Physiology and Chronic Health Evaluation II score at admission 17.8 +/- 6.7; 239 paired samples were taken from arterial catheters. Mean AccuChek whole blood glucose was 126 +/- 36 mg/dL (7.0 +/- 2.0 mmol/L); mean central laboratory serum glucose was 137 +/- 38 mg/dL (7.6 +/- 2.1 mmol/L). Mean difference was 11 mg/dL (0.61 mmol/L) (8%) (95% Confidence Interval 9-13 mg/dL, p < .001). ISO 15197 guideline requires 95% of point-of-care measurements to be within 15 mg/dL margins with reference <75 mg/dL or within 20% if reference is higher. In total, 216 (90.4%) of AccuChek measurements were within ISO 15197 margins. Because AccuChek was calibrated to give whole blood results, we calculated a correction factor of 1.086 from the two mean values to correct whole blood AccuChek into serum-like results. This is almost the same as the correction factor of 1.080 given by Roche Diagnostics. By multiplying AccuChek whole blood results with 1.086, 225 (94.1%) of results were within the ISO 15197 margins. Hematocrit did not influence AccuChek results in the 0.20 to 0.44 range. Beyond this range, there were not enough data to draw conclusions. CONCLUSIONS: In critically ill patients, the accuracy of AccuChek glucose measurement calibrated to give serum-like results with blood samples derived from arterial catheters is acceptable but falls short by about 1% of complying with the ISO 15197 guideline.

Introduction and evaluation of a computerised insulin protocol.

OBJECTIVE: To lower glucose levels in all patients in the intensive care unit (ICU) to the target range of 4.5-7.5 mmol/l using a nurse-driven computerised insulin protocol in combination with bedside glucose measurement. DESIGN: Cohort study. SETTING: Mixed adult ICU. PATIENTS AND PARTICIPANTS: All 182 patients admitted to the ICU during a 3-month period were studied, except for 3 patients admitted for diabetic keto-acidosis. INTERVENTIONS: Five steps were taken to improve glucose regulation: (1) Nurses were authorised to adjust insulin dosage using a protocol. (2) Glucose was measured more often. (3) Glucose was measured at the bedside. (4) Consecutive protocols aimed for successively lower glucose levels; the final protocol had a target range of 4.5-7.5 mmol/l. (5) The protocol was computerised. MEASUREMENTS AND RESULT: Mean glucose decreased from 9.23 mmol/l without protocol to 7.68 mmol/l with the final protocol. This final protocol with the target of 4.5-7.5 mmol/l was evaluated more extensively. Glucose levels were measured a total of 1854 times in 179 ICU admissions during 552 ICU treatment days. The median glucose level was 7.0 mmol/l, and 53.1% of glucose measurements were within the target range of 4.5-7.5 mmol/l. One episode of hypoglycaemia (glucose