Bedside Glucometry Research Articles

The great mimicker: Acute catatonia secondary to acute hypoglycemia

A 58-year-old man with diabetes and human immunodeficiency virus presented to the emergency department in a state of acute catatonic rigidity, with the inability to speak, and the inability to relax his upper and lower limbs with gravity. Bedside glucometry

Accuracy of bedside glucometry in critically ill children with peripheral hypoperfusion.

The accuracy of glucose test strip in critically care has been questioned. We investigated the accuracy of glucose test strip in critically ill children. Patients, aged from 1 month to 18 years admitted in pediatric intensive care unit. Demographic data, hemodynamic parameters, and perfusion index (PI) were recorded. Glucose test strips were performed from finger stick blood [capillary blood glucose (CBG)] and from whole blood [whole blood glucose (WBG)] along with laboratory plasma blood glucose (PBG) from either arterial or venous blood samples. The accuracy of glucose test strips was defined according to ISO 15197 and Clarke error grid (CEG). One hundred and eighty one blood samplings including 117 arterial blood (CBG, WBGa, PBGa) and 64 venous blood (CBG, WBGv, PBGv) were obtained. The accuracy of WBGa was 98.3 and 95.2% when compared to the accuracy of CBG (88.7 and 83.3%. The accuracy of WBGv was 92.2% and 87.0 when compared to the accuracy of CBG which was 79.7 and 72.9% (ISO 15197: 2003 and 2013, respectively). Bland-Altman plot demonstrated bias and precision of 7.4±17.7 mg/dL in acceptable PI group compared to 30.2±23.4 mg/dL in low PI group (PI≤0.3). The CBG test strip must be interpreted carefully in critically ill children. A low PI was associated with poor CBG strip accuracy. WBG test strip from arterial blood was more appropriate for glucose monitoring in children with peripheral hypoperfusion.

In-Hospital Management of Diabetes.

In-Hospital Management of Diabetes.

Accuracy of Bedside Glucometry in Critically Ill Patients: Influence of Clinical Characteristics and Perfusion Index

Accuracy of Bedside Glucometry in Critically Ill Patients: Influence of Clinical Characteristics and Perfusion Index

Comparison between arterial and capillary blood glucose monitoring in patients with shock

Background The accuracy of bedside glucometry using capillary blood is contentious in patients admitted to intensive care units. We aimed to compare the accuracy of capillary bedside glucometry with arterial samples in critically ill patients with shock through a prospective case–control study. Methods Study group consisted of 100 patients with shock on vasopressor support and control group had 100 normotensive patients. Arterial and capillary samples were taken simultaneously and were tested immediately at the bedside. Results of the paired measurements were analyzed as a scatter plot by Bland and Altman method and were expressed as a correlation coefficient. Values were considered to disagree significantly when the difference exceeded 20%. Results Mean arterial and capillary sugars (mg/dl) in study and control groups were 164.7 ± 70 and 157.4 ± 68.9, and 167.1 ± 62.2 and 167.5 ± 61, respectively. On Bland–Altman analysis, 6% in study group and 5% in control group were out of range (acceptable limit < 5%). Correlation between capillary and arterial values was less in the study group (r = 0.917, p < 0.001 vs r = 0.979, p < 0.001). In addition, the disagreement between capillary and arterial values was more than 20% in 18% of the patients in the study group vs 3% in control group (p = 0.015) (ISO standard < 5%). Conclusions Capillary blood glucose monitoring is reliable only in a selected group of ICU patients. Hence, caution must be exercised especially in patients with shock in whom arterial blood may be preferred.

Continuous subcutaneous glucose monitoring: good enough to use in glucose regulation protocols?

Tight glucose regulation is benefi cial in subgroups of inten sive care unit (ICU) patients, but may harm other sub groups. Th is harm may be due to hypoglycemic events. In avoiding hypoglycemia, an accurate bedside glucometry method is essential [1]. Bridges and colleagues therefore evaluated the accuracy of a continuous subcutaneous glucose monitoring system (CGMS) in critically ill children, and concluded that the system proves highly accurate [2]. We have a problem with this resolute conclusion. Th ey report a Pearson’s correlation coeffi cient of 0.68, which is quite low. Vlkova and colleagues even conclude that, based on a correlation coeffi cient of 0.69 comparing subcutaneous glucose values and laboratory blood glucose values in 15 patients, subcutaneous devices should not be used in critically ill patients [3]. We found a correlation coeffi cient of 0.87 in evaluating the same CGMS in 60 critically ill patients, but were concerned with the inaccuracy in the low glucose zone: we found a diff erence of nearly 4 mmol/l (reference blood glucose 2.8 mmol/l versus subcutaneous sensor 6.5 mmol/l) in one patient [4]. Bridges and colleagues report 142 subcutaneous glucose readings <2.2 mmol/l that were falsely low, checked against blood glucose values. Th e Clarke error grid is a better way to evaluate the accuracy of a CGMS than Pearson’s correlation coeffi cient. In most published studies, the deviation of subcuta neous measurements stays in the (wide) clinically accep table zones of the Clarke error grid. Th ese deviations of the CGMS system, however, when used in a tight glucose regulation protocol – and adjusting the insulin dose based on the subcutaneous readings – could have severe consequences in the individual patient, if the deviations result in an unjust rise in insulin dose. Since computerized protocols based on arterial blood samples give excellent glucose regulation with a negligible chance of hypoglycemic events [5], we decided to continue using this computerized protocol to avoid treatment-related morbidity. Subcutaneous CGMS seems not good enough in aiming for tight glucose regulation in the ICU. Intravascular CGMS, used in a closed feedback loop with insulin infusion, is promising, but has not yet been evaluated in clinical studies in critically ill patients.

Unrecognized hypoglycemia due to maltodextrin interference with bedside glucometry

Glucometry is widely used to confirm or exclude hypoglycemia in patients with suggestive clinical findings. Nonglucose sugars may be detected by certain types of glucometers, causing false elevation of the glucometer analysis of the blood sugar. Since these other sugars are not functionally glucose and may even induce excess insulin release, clinical hypoglycemia may be missed. We report a 79-year-old man on enteral feeds containing maltodextrin, a glucose polymer, who had persistently high glucometer-measured blood glucose despite normal blood glucose measured by formal laboratory analysis. Excess insulin administration, based on the erroneous glucometer reading, may have caused unrecognized fatal clinical hypoglycemia. This has been reported following intravenous administration of related nonglucose sugars but not with enteral maltodextrin. Further study is required to confirm the effects of maltodextrin on glucometry. False elevation of blood glucose measured on certain point-of-care glucometers can occur following the oral administration of maltodextrin.

Accuracy of Bedside Glucometry in Critically Ill Patients: Influence of Clinical Characteristics and Perfusion Index

Accuracy of Bedside Glucometry in Critically Ill Patients: Influence of Clinical Characteristics and Perfusion Index

Accuracy of Bedside Glucometry in Critically Ill Patients: Influence of Clinical Characteristics and Perfusion Index

Accuracy of Bedside Glucometry in Critically Ill Patients: Influence of Clinical Characteristics and Perfusion Index

Accuracy of Bedside Glucometry in Critically Ill Patients: Influence of Clinical Characteristics and Perfusion Index

To determine the accuracy of bedside glucose strip assay on capillary blood and on whole blood and to identify factors predictive of discrepancies with the laboratory method. We conducted a prospective 3-month (July 1-September 30, 2003) study in 85 consecutive patients who required blood glucose monitoring. Values obtained with a glucose test strip on capillary blood and on whole blood were compared with those obtained in the laboratory during serial blood sampling (up to 4 samples per patient). The test strip values were considered to disagree significantly with the laboratory values when the difference exceeded 20%. Clinical and biological parameters and the perfusion index, based on percutaneous oxygen saturation monitoring, were recorded when each sample was obtained. Capillary glucose values conflicted with laboratory reference values in 15% of samples. A low perfusion index was predictive of conflicting values (P=.04). Seven percent of values obtained with glucose strip on whole-blood samples conflicted with laboratory reference values; factors associated with these discrepancies were mean arterial hypotension (P=.007) and generalized mottling (P=.04). Bedside blood glucose values must be interpreted with care in critically ill patients. A low perfusion index, reflecting peripheral hypoperfusion, is associated with poor glucose strip performance. Bedside measurements in whole blood seem to be most reliable, except in patients with arterial hypotension and generalized mottling.

Accuracy and feasibility of point-of-care and continuous blood glucose analysis in critically ill ICU patients

IntroductionTo obtain strict glucose regulation, an accurate and feasible bedside glucometry method is essential. We evaluated three different types of point-of-care glucometry in seriously ill intensive care unit (ICU) patients. The study was performed as a single-centre, prospective, observational study in a 12-bed medical ICU of a university hospital.MethodsPatients with an expected ICU stay of more than 48 hours were included. Because the reference laboratory delivers glucose values after approximately 30 to 60 minutes, which is too slow to use in a glucose regulation protocol and for calibration of the subcutaneous continuous glucose monitoring system (CGMS) (CGMS System Gold), we first validated the ICU-based blood gas/glucose analyser ABL715 (part 1 of the study). Subsequently, part 2 was performed: after inserting (and calibrating) the subcutaneous CGMS, heparinised arterial blood samples were drawn from an arterial line every 6 hours and analysed on both the Precision PCx point-of-care meter using test strips and on the blood gas/glucose analyser ABL715. CGMS glucose data were downloaded after 24 to 72 hours. The results of the paired measurements were analysed as a scatter plot by the method of Bland and Altman and were expressed as a correlation coefficient.ResultsPart 1: Four hundred and twenty-four blood samples were drawn from 45 critically ill ICU patients. The ICU-based blood gas/glucose analyser ABL715 provided a good estimate of conventional laboratory glucose assessment: the correlation coefficient was 0.95. In the Clarke error grid, 96.8% of the paired measurements were in the clinically acceptable zones A and B. Part 2: One hundred sixty-five paired samples were drawn from 19 ICU patients. The Precision PCx point-of-care meter showed a correlation coefficient of 0.89. Ninety-eight point seven percent of measurements were within zones A and B. The correlation coefficient for the subcutaneous CGMS System Gold was 0.89. One hundred percent of measurements were within zones A and B.ConclusionThe ICU-based blood glucose analyser ABL715 is a rapid and accurate alternative for laboratory glucose determination and can serve as a standard for ICU blood glucose measurements. The Precision PCx is a good alternative, but feasibility may be limited because of the blood sample handling. The subcutaneous CGMS System Gold is promising, but real-time glucose level reporting is necessary before it can be of clinical use in the ICU. When implementing a glucose-insulin algorithm in patient care or research, one should realise that the absolute glucose level may differ systematically among various measuring methods, influencing targeted glucose levels.

Agreement Between Bedside Blood and Plasma Glucose Measurement in the ICU Setting

To assess the agreement between bedside glucose (bGlu) measurements and laboratory plasma glucose (pGlu) measurements in the ICU setting. Retrospective study. ICU of a tertiary academic medical center. One hundred ninety-seven patients admitted to the ICU from January through December 2002 who underwent 816 simultaneous bGlu and pGlu measurements. None. To calculate the agreement between the two methods of glucose measurement, the mean difference was obtained, and the limits of the agreement were calculated as the mean difference +/- 2 SDs. On 767 occasions, the mean bGlu was 159 mg/dL and the mean pGlu was 151 mg/dL (p < 0.001). The mean difference between the two techniques was 7.9 mg/dL (SD, 17.6 mg/dL), and the limits of agreement were + 43.1 and -27.2. On 31 occasions, the bGlu was reported as > 400 mg/dL, and in these cases the mean pGlu was 423 mg/dL (range, 300 to 900 mg/dL). On 18 occasions, the bGlu was reported as < 50 mg/dL, and in these cases the mean pGlu was 66.9 mg/dL (range, 13 to 198 mg/dL). On average, bGlu provides a reasonable estimate for pGlu. However, for the individual patient, bGlu gives an unreliable estimate for pGlu. All of those taking care of critically ill patients should be aware of the limitations of bedside glucometry.

Accuracy of blood glucose measurements in the intensive care unit

Strict glucose control in critically ill patients may improve survival. According to the Van den Berghe protocol frequent glucose measurements are needed. In the original protocol, however, measurements are made by a blood gas analyzer that is not accessible to our unit. Measurements in the core chemistry laboratory are time and staff consuming and unpractical because of a time delay of about half an hour. According to some other protocols, bedside glucometry is a proposed solution, which is easily accessible and not time consuming. In our preliminary phase of adopting the aforementioned protocol we observed some clinically suspected cases of hypoglycemia, which were not confirmed by the bedside glucometry. However, glucose measurements in the core laboratory confirmed our suspicion. The question arose whether bedside glucose measurements are accurate enough to be performed in so strict a protocol as that of Van der Berghe.

Pilot study of the accuracy of bedside glucometry in the intensive care unit.

To evaluate the accuracy of bedside glucometry among critically ill patients. Prospective audit, with sequential specimen collection. Thirty-two-bed cardiovascular, neurosurgical, and medical-surgical intensive care unit in a single Canadian center. Ten critically ill adults, who were sequentially followed during their intensive care unit stay. Eight had diabetes mellitus, and three were in shock. Repeat arterial blood samples were obtained by the attending nurse, who withdrew a portion of the sample and performed reflectance glucometry at the bedside. The remainder was immediately sent in a vacuum-sealed plasma separation tube to the hospital laboratory, and analyzed using a conventional plasma glucose analyzer by a laboratory technologist. Sequential samples were taken at intervals of at least 12 hrs of one other. A total of 105 arterial glucose pairs were obtained. There was a significant correlation between the laboratory and glucometry determined glucose concentrations (intraclass correlation coefficient = 0.86, p <.0001). The overall average laboratory-glucometry glucose difference was -0.04 mmol/L (95% confidence interval [CI] -2.3-2.2 mmol/L). Five out of 105 values (4.8%) lay beyond these confidence bounds. The square of the Pearson correlation coefficient (r(2)) between the mean glucose level and the laboratory-glucometry glucose difference was not significant (0.01, 95% CI 0.005-0.04; p =.22), suggesting the absence of any trend between rising glucose concentration and the laboratory-glucometry difference. Bedside glucose testing of arterial whole blood samples may be an accurate alternative to laboratory plasma glucose measurement among critically ill adults, within approximately 2.3 mmol/L of certainty. Because previous studies have suggested that this bedside technique may be prone to a moderate degree of error among patients in shock as well as those with an abnormal blood pH or hematocrit, larger studies are needed to confirm our findings.