Bedside Glucose Research Articles

Survey of the definition and screening of neonatal hypoglycaemia in Australia.

To determine the approach to identifying neonatal hypoglycaemia and the definition of neonatal hypoglycaemia used by neonatal paediatricians in Australian Level 3 neonatal intensive care units (NICU). A questionnaire was sent to the 101 neonatal paediatricians in the 22 Level 3 NICU in Australia asking their method of screening for, and definition of, neonatal hypoglycaemia. Responses were received from 70 neonatal paediatricians, including all 22 directors. A bedside glucose meter is used in 19 of 22 NICU to screen for hypoglycaemia, whilst one NICU uses a glucose analyzer and another NICU uses a visual colour comparison method. One NICU does not screen, but has blood glucose measured in a satellite laboratory. If the screening method suggests hypoglycaemia, 62 of 63 neonatal paediatricians proceed to blood glucose determination in a laboratory, mostly using plasma samples. Based on the laboratory measurement, the definition of neonatal hypoglycaemia ranged from < 1.1 to 3.0 mmol/L. The majority of neonatal paediatricians in Australian NICU screen for neonatal hypoglycaemia using a bedside glucose meter. There is a wide range in the definition of neonatal hypoglycaemia from < 1.1 to 3.0 mmol/L.

The short insulin tolerance test: feasibility study using venous sampling.

The short insulin tolerance test (ITT) is both a simple and valid method of quantifying insulin sensitivity although arterialization of samples and the risk of hypoglycaemia remain as potential difficulties. We examined the safety and reproducibility of using venous sampling with insulin doses of 0.1 U kg-1 and 0.05 U kg-1 in healthy subjects. Whole blood glucose concentrations were measured contemporaneously and the rate of plasma glucose decline (mmol l-1 min-1) for each test was estimated from unlogged venous plasma glucose concentrations measured at 1 min intervals. The mean rates of plasma glucose decline for the 0.1 U kg-1 and 0.05 U kg-1 insulin doses were 0.26 mmol l-1 min-1 (n = 11, range = 0.17-0.41, intrasubject coefficient of variation (CV) = 9.4%) and 0.25 mmol l-1 min-1 (n = 6, range 0.19-0.46, intrasubject CV = 15.9%), respectively. Reversal of significant hypoglycaemia was necessary in one subject before 15 min post-insulin. We found that: (1) venous sampling provides a reproducible measure of glucose uptake after insulin, (2) contemporaneous bedside glucose sampling identifies those at risk of significant hypoglycaemia during the ITT, and (3) the 0.1 U kg-1 dose response is more reproducible and no less safe than the half dose response. We conclude that the current ITT protocol would be made safer and simpler with the above modifications although further studies comparing venous with arterialized sampling are needed.

Utility of routine admission serum chemistry panels in adult trauma patients.

To determine the frequency of abnormal serum chemistries and whether they provide clinically useful information regarding trauma patients. To identify clinical criteria associated with critical serum chemistry values (CSCVs). The records of all trauma patients admitted to one urban, Level I Trauma Center were retrospectively reviewed for the period (July 1-December 31, 1989). All trauma patients who had had serum chemistry determinations at hospital admission and at least once more prior to discharge were studied. The CSCVs were determined by a panel of experts prior to record review. Serum chemistry values, patient demographics, mechanisms of injury, and outcomes were statistically analyzed. Most (814/913; 89%) trauma patients had abnormal serum chemistry values. However, only 54/913 (6%) had CSCVs and only six of these CSCVs had prompted a change in resuscitation or treatment (therapeutic K+ infusions). Age > 50 years, a history of hypertension therapy, and a Glasgow Coma Scale score < or = 10 were associated with CSCVs; and CSCVs were correlated with increased mortality and critical care unit admission. Routine-admission serum chemistry values, while frequently abnormal for major trauma patients, generally do not provide clinically useful information in the resuscitation and treatment of trauma patients. Hypoglycemia and metabolic acidosis were more rapidly determined using bedside glucose determination and arterial blood gas evaluation. The routine-admission serum chemistry panel described in the study lacked utility for most trauma patients. Selective chemistry panel ordering should be used at the time of hospital admission for major trauma patients.

Accuracy of fingerstick glucose values in shock patients

Fingerstick blood glucose measurement has become widespread in both hospital and prehospital settings. To determine the accuracy of fingerstick blood glucose measurement in patients with poor peripheral perfusion (shock). Results obtained during three methods of glucose analysis (fingerstick blood glucose measurement; bedside and laboratory glucose analysis) were examined prospectively on 38 patients from inpatient medical and surgical critical care units or the emergency department of a large tertiary care referral center. The means of the three glucose measurements were significantly different. Univariate analysis of the mean laboratory glucose value versus the mean fingerstick glucose value was significantly different. The mean venipuncture glucose measured by the bedside glucose meter versus the mean venous laboratory glucose was not significantly different. These results suggest that fingerstick blood samples should not be used for bedside glucose analysis in patients who may have inadequate tissue perfusion.

Hematology Testing at the Bedside

Bedside testing is appropriate for analyses in which rapid answers lead to immediate therapeutic decisions. Bedside testing instruments are designed for use by individuals without technical laboratory training. Hematology systems perform tests such as activated clotting time, spun hematocrit, hemoglobin, prothrombin time, and activated partial thromboplastin time. This article reviews the quality management procedures required by several accrediting and regulatory bodies, including the Clinical Laboratory Improvement Amendments of 1988 and the Joint Commission on Accreditation of Healthcare Organizations. In the future, more of these systems may be placed in hospitals and other patient care settings, and the laboratory's role in managing testing quality will increase. This is the final article in a two-part continuing education series on bedside testing. The first article focused on data management of bedside glucose testing.

Testing at the Patient’s Bedside

Performing laboratory tests at the patient's bedside has become a popular component of care, primarily because of the immediate availability of test results. Bedside glucose monitoring programs have been the prototype for bedside testing and have provided the most experience in this area. Studies of bedside glucose testing have shown that in order to obtain reliably accurate results, there must be a well-designed and well-implemented quality assurance program, which should involve laboratory professionals. However, medical necessity, cost, and alternatives should be thoroughly considered before beginning a bedside testing program, as well as the commitment to a strong quality assurance program.

Utilization and cost analysis of bedside capillary glucose testing in a large teaching hospital: Implications for managing point of care testing

purpose: To study the use and cost of bedside capillary glucose testing in a large teaching hospital. patients and methods: In a prospective study of 40 inpatient units and 10 outpatient units at Massachusetts General Hospital, records were maintained by each unit of the date, time, operator, and results of patient and quality control tests. Cost analysis was performed using data from time studies, test tallies in logbooks, and hospital administration records. results: The number of glucose meters in the hospital increased from 10 to 54 over a 2-year period. In 1992, 67,596 tests were performed by the bedside method, representing 30.7% of all glucose measurements performed in the institution. The majority of tests (94.7%) were performed on inpatients, and 10.2% of all hospital admissions underwent bedside glucose testing. The impact on the number of glucose tests performed in the clinical laboratories was minimal, indicating that bedside glucose testing was added as an extra test rather than as a substitute for laboratory-based glucose measurements. The cost of bedside glucose testing was $4.19 per test compared with $3.84 in the clinical laboratory. The cost varied from one unit to another (median $5.52, range $3.08 to $48.16), an effect largely attributed to the difference in the volume of tests performed by different units. In seven high-volume units the cost per test was lower than the corresponding value in the laboratory. The cost of bedside glucose testing included labor (80.2%) and supplies (19.8%). The percent of costs attributed directly to patient testing was 57.7%, whereas the costs for all other related activities (training, quality control, and quality assurance) was 42.3%. conclusions: Bedside capillary glucose testing is a rapidly expanding technology and is performed on a significant percentage of hospital admissions. Bedside glucose testing is not inherently more expensive than centralized laboratory measurements but implementation on inefficient care units with low utilization can add substantially to the cost. Much of the excess cost of the bedside method can be attributed to the high costs of quality control and quality assurance, training, and documentation.

Bedside glucose monitoring in nurses education

Bedside glucose monitoring in nurses education

Use of arterial blood with bedside glucose reflectance meters in an intensive care unit

To compare blood glucose values obtained from two different sampling sites (arterial catheter and capillary from finger puncture), which were analyzed by a bedside reflectance meter. A sample was also analyzed by standard methods (oxygen electrode oxidation in the laboratory). Prospective, cross-sectional clinical study. Cardiovascular intensive care unit (ICU) designed for postoperative open-heart surgery patients in a 1,100-bed medical center. Sequential sample of 50 patients immediately after open-heart surgery. The blood glucose concentration of each patient was analyzed on the patient's arrival to the ICU (immediately postoperatively) by three methods: one blood specimen was obtained from an arterial catheter, divided and analyzed either at the bedside by a reflectance meter (glucose method 1) or in the hospital laboratory (glucose method 2); another sample was obtained by lancing the fingertip and the glucose concentration was analyzed at the bedside in the same reflectance meter (glucose method 3). Using paired analyses to compare the mean glucose values of the bedside arterial whole blood sample (method 1) with the arterial serum sample (method 2) demonstrated that the glucose concentration in the arterial whole blood sample (method 1) was significantly (p < .001) higher. For 46 of 50 comparisons, the glucose value in the arterial whole blood sample (method 1) was higher, with a mean difference of 30 mg/dL (1.7 mmol/L). Although the mean difference was reduced to 10 mg/dL (0.6 mmol/L) when the arterial whole blood sample (method 1) was corrected for the hematocrit (i.e., < 35% [< 0.35]), the mean glucose concentration in the arterial whole blood samples (method 1) remained statistically higher (p < .05). The glucose concentration in the arterial serum sample (method 2) was significantly higher than the value determined from the bedside capillary sample (method 3) before (p < .05) and after (p < .001) correction for hematocrit. The difference in mean glucose concentrations between the arterial serum sample (method 2) and bedside capillary sample (method 3) was 9 mg/dL (0.5 mmol/L) when the capillary specimen (method 3) was not corrected for hematocrit. This difference increased to 21 mg/dL (1.2 mmol/L) when low hematocrit values were considered and appropriate adjustments of the glucose values were made. At the bedside, one can accurately correct arterial whole blood glucose values to correspond to laboratory values by the following formula: (0.94 x arterial whole blood glucose) + (4.6 x hematocrit) + (-16.5 x [37 degrees C--patient's temperature])--132 = laboratory glucose value. Since arterial whole blood samples give higher glucose results than arterial serum, the use of arterial whole blood in combination with reflectance meters must be recommended with caution. This caution is especially advised if the glucose values obtained with arterial whole blood are used in conjunction with a sliding scale of insulin, which depends on threshold concentrations of glucose. In our hospital, use of arterial whole blood in combination with reflectance meters could have resulted in an incorrect dose of insulin in 31 of 50 patients.

Designing and implementing a comprehensive quality assurance program for bedside glucose testing.

A program for bedside glucose testing has been successfully implemented and in operation at Sharp Memorial Hospital since October 1990. The nursing staff training and certification process focuses on gaining an understanding of the issues and skills needed to routinely perform the tests to laboratory quality standards. Routine quality control checks are performed to ensure the accuracy and precision of the glucose values obtained on patients, thus maintaining quality in the process. Instituting this comprehensive QA program for bedside glucose testing has enabled us to improve the accuracy of our measurements and increase the quality of our patient care.

A comparison of four glucose monitors in a hospital medical surgical setting.

Four bedside glucose monitors were evaluated and compared for accuracy in correlation with concomitant laboratory glucose values. Of these four monitors--Diascan, Glucometer Q.A., Accucheck, and One Touch--two bedside glucose monitors were comparable with a correlation coefficient of 0.91 for Glucometer Q.A. and 0.90 for One Touch. These two machines were then evaluated for precision and linearity. Although the Glucometer Q.A. was more precise for all three levels of glucose, the One Touch linearity was almost perfect. Lastly, in asking nursing staff for an evaluation of One Touch and Glucometer Q.A., 15 of 16 staff members preferred One Touch.

Cost Analysis of Bedside Glucose Testing

Cost Analysis of Bedside Glucose Testing

Bedside Glucose Monitoring: In Compliance With Regulatory Standards

When accurately performed, bedside glucose monitoring (BGM) is a prompt, reliable, and cost-effective method of managing patients who require a high degree of glucose control. However, regulatory agencies have criticized the quality-control deficiencies of most existing BGM programs. A new generation of multi-user reflectance meters enables the various regulatory directives to be more easily satisfied. These meters provide computer-assisted quality control analysis and facilitate operator feedback for each control test. New York State Department of Health regulations state that the ultimate responsibility for BGM belongs to the chemistry laboratory director. We believe that nursing personnel should retain their patient care prerogative to perform glucose monitoring. Implementation of our successful BGM program required the collaboration of nursing, medical, laboratory, and administrative personnel. These departments combined theoretical and practical expertise with material and financial management. During the first 5 months of operation, our program has shown a steady increase from 78% to 89% of control tests performed correctly. This model can be used by other hospitals to achieve a successful BGM program.

Hypoglycemia in Infancy: The Need for a Rational Definition

A discussion meeting was held on October 17, 1989, to address the current status of the definition of significant hypoglycemia in infancy, especially in the normal- and low-birth-weight neonate. Robert Schwartz introduced the complexity of the problem by indicating the multiple variables (duration, severity, cerebral blood flow, rates of glucose uptake, availability of alternate substrates, oxygen, etc) in equating a plasma glucose value with neurodevelopmental consequences. Marvin Cornblath reviewed the various definitions of hypoglycemic blood sugar levels reported since 1911 which depend upon the method of blood sugar analysis, clinical recognition and concerns. Severe symptomatic hypoglycemia that persisted or recurred was first reported in neonates in 1937. Lower blood sugar levels, documented since the 1920s in both full-term and premature newborns, had been considered physiologic. The recognition of transient significant hypoglycemia first in symptomatic and then in asymptomatic small-for-gestational-age, neonates required new definitions in the 1960s. These definitions were later modified as changes in treating both the mother in labor and at delivery and the neonate occurred. Intensive care and the survival of very-low-birth-weight newborns have compounded the problem of definition. Currently methods are available to correlate plasma glucose concentrations and glucose metabolism in vivo in the brain with specific neurologic dysfunctions. This should permit a better definition of the continuum of significant hypoglycemia than has been available before. William Hay analyzed studies of the various rapid bedside glucose oxidase stick techniques used to screen for blood glucose concentrations. He concluded that their dependence on the hematocrit, their requirements for precision in performance and timing, great variance (±5 to 15 mg/dL), and lack of reproducibility, especially at blood glucose values less than 50 mg/dL, made their use in the neonate unsatisfactory (whether read by eye or by meter).

Bedside cerebrospinal fluid glucose analysis.

We studied the reliability and accuracy of a two-minute reagent strip (Chemstrip bG) and hand-held autoanalyzer (Accu-Chek IIR) for determining cerebrospinal fluid glucose. We found that both bedside methods were highly reliable (r = 0.93, Chemstrip bG: r = 0.95, Accu-Chek II) and were very accurate (89.7% and 96.6% accurate at +/- 15 and 20 mg/dL, respectively, for the Chemstrip bG: 91.7% and 95.8% accurate at +/- 15 and 20 mg/dL, respectively, for the Accu-Chek II) over a wide range of glucose values in 237 determinations. There was no significant difference between the two bedside methods. We conclude that these two methods of bedside glucose estimation are both highly reliable and accurate and could be used to quickly determine patients' cerebrospinal fluid glucose values.

Evaluation of the Reliability of Bedside Glucose Testing

A review of six months of patients' records showed that glucose values obtained on the wards by nurses with various chemistry reagent strips differed significantly from those obtained by the laboratory. The differences could be as much as 12mmol/L(216mg/dL). The bias found seemed to apply to all brands of strips used; 58.7% of glucose results obtained by strip with manual reading had a bias exceeding 20% of those results obtained by the laboratory, and 15.7% of glucose results had a difference of greater than 10mmol/L(180mg/dL). When meters were used to read the strip color, the percentage of discrepancies was 47.0%. Similar results were obtained in the concurrent study, although the discrepancies were less when meters were used for reading the strip color. Our studies suggest that user-to-user variability, lack of quality control, lack of stringent staff training, and education criteria may all contribute to the variability and poor performance found. These points must be addressed if bedside glucose monitoring is to be of practical value, thus ensuring reliability in the management of diabetic patients.

The effect of glucose priming solutions in diabetic patients undergoing coronary artery bypass grafting : Stephens JW, Krause AH, Peterson CA, et al: Ann Thorac Surg 45:544–547, 1988

To assess the impact of glucose-containing priming solutions on plasma glucose level in diabetic patients during and after coronary artery bypass graft surgery, we studied 50 diabetic patients and 10 nondiabetic patients who underwent bypass graft surgery. Glucosecontaining priming solutions profoundly elevated plasma glucose levels during and after bypass graft surgery. In diabetic patients who received glucose primes, intraoperative peak plasma glucose levels averaged 696 + 48 mg/dl as compared with 341 _+ 17 mg/dl in diabetic patients who received nonglucose primes (p < 0.001). Despite an insulin infusion, diabetic patients underwent a much slower decline in plasma glucose levels postoperatively over a 2hour period than did nondiabetics (who did not receive an insulin infusion). We conclude that during and immediately after coronary artery bypass surgery in diabetic patients, it is desirable to avoid administration of glucosecontaining priming solutions, since such solutions profoundly elevate plasma glucose levels. Updated in 1995 by W. Kenneth Ward, MD, and Albert H. Krause, Jr, MD Portland Diabetes and Endocrinology Center and Northwest Surgical Associates, Inc, Portland, Oregon W e continue to give continuous insulin infusions to patients with diabetes who undergo coronary artery bypass grafting. Generally we start the insulin infusion 3 to 5 hours before the operation and continue it until the patients are able to eat postoperatively. In patients whose diabetes is poorly controlled (for example, in those whose preoperative blood glucose level is more than 300 mg/dL), the infusion is initiated the evening before the operation. At Good Samaritan Hospital, every year we treat about 150 patients undergoing coronary artery bypass grafting with insulin infusions. Glucose was eliminated from the priming solutions when we completed the above-mentioned study [1]. Rates of insulin infusion for patients who take insulin (whether they have type I or type II diabetes) can be estimated from Table 1. The infusion rate is based on the total daily outpatient insulin dose (the sum of all types of insulin). A general rule is that an insulin drip always should be accompanied by a concomitant dextrose infusion, typically 5% dextrose at 100 to 125 mL/h (10% dextrose can be used if fluids must be restricted). The nurses adjust the infusion based on fingerstick capillary blood glucose tests performed at the bedside every I to 2 hours. When blood glucose values are very stable postoperatively, the frequency of testing can be extended to Address reprint requests to Dr Ward, Portland Diabetes and Endocrinology Center, 1130 NW 22 Ave, Suite 400, Portland, OR 97210. every 3 to 4 hours. A reasonable goal for perioperative glucose levels is 100 to 180 mg/dL. Patients who have type II diabetes and are not receiving insulin as outpatients should nonetheless be treated with insulin infusions; otherwise, they usually will become markedly hyperglycemic intraoperatively and postoperatively. The amount of body fat is the best means of estimating insulin infusion rate in these individuals. Thin patients (or patients who are very physically active) are sensitive to insulin and usually do well with lower rates. Obese individuals, whose tissues are insulin resistant, require higher doses (ie, infusion rates on the right in Table 1). Because marked insulin resistance during and shortly after operation is the rule, we continue to double the insulin infusion rate when the thorax is open. However, even with the doubling of the rate, hyperglycemia usually occurs intraoperatively and for a few hours after the operation (range, 200 to 350 mg/dL). At a point 8 hours after operation, most patients have blood glucose values less than 240 mg/dL. If not, the insulin scale is raised (eg, by increasing the scale by one column to the right in Table 1). Only 10% to 15% of patients experience blood glucose values of less than 80 mg/dL on this regimen. Even then, the hypoglycemia is rarely severe for the following reasons: (1) the insulin infusion, but not the dextrose infusion, is discontinued according to standing orders when the glucose level is less than 80 mg/dL. (2) As mentioned, bedside glucose moni© 1995 by The Society of Thoracic Surgeons Ann Thorac Surg 1995;59:1259-60 • 0003-4975/95/$9.50 0003-4975(95)00002-3 1260 UPDATE WARD AND KRAUSE Ann Thorac Surg INSULIN INFUSIONS AND CORONARY BYPASS GRAFTING 1995;59:1259-60 Tabel 1. Maintenance Regular Insulin Infusion Rate ~ for Patients With Diabetes Undergoing Coronary Artery Bypass Grafting Total daily insulin requirement (U/day) Blood Glucose (mg/dL) 20-30 31-50 51-70 71-90 91-120

Surgery and Diabetes

Medical treatment of the diabetic patient undergoing surgery is described. Intravenous insulin is emphasized for all patients, except the type II diabetic patient controlled on diet therapy. Frequent metabolic monitoring of the patient is critical to a successful outcome. Bedside glucose monitoring is the most important advance during the last decade for monitoring the patient.

Managing Bedside Glucose Testing in the Hospital

The scope and magnitude of bedside testing by personnel without formal laboratory training have recently increased. There has been some question about the reliability of bedside test results produced by nurses, physicians, and other ward staff that are used in clinical decisions. Glucose testing is currently the most widely performed bedside test. Because of the likelihood that the use of bedside testing will increase in the future, this article discusses various issues concerning bedside glucose analysis, including the scope of such testing, staff responsibilities, training and supervision, testing frequency, work flow and result reporting, and the reliability of bedside glucose results, in three institutions. We also suggest an approach to bedside testing quality management.

Managing bedside glucose testing in the hospital

Managing bedside glucose testing in the hospital