The FDA approved the Nova StatStrip Glucose Hospital Meter System for use among all hospitalized patients on September 24, 2014.1 Nova StatStrip’s system was first approved for such use by the FDA in 2006 to help monitor the effectiveness of a diabetes control program. The recent approval extends the use of this continuous glucose monitoring system in all capacities, including monitoring critically ill patients.
Multiple studies have shown that Nova StatStrip, which is indicated for hospitalized patients on complex medication regimens, accurately reports blood glucose levels when healthcare providers test patients with a wide array of medical conditions, including cardiopulmonary disease, endocrine disorders, malignancies, obstetric or gynecologic issues, renal disease, surgery, and trauma. Moreover, this device can use arterial or venous whole blood obtained from hospitalized patients of all ages, including neonates, children, and adults.
Glucometers (or blood glucose meters) are handheld instruments that allow healthcare workers to test blood glucose levels at the bedside. A single drop of blood pricked from the patient’s finger is applied to a plastic strip, which is then inserted into the glucometer. Glucose in the blood reacts with an enzyme on the test strip, and the chemical reaction creates an electrical current, which is measured and displayed as a surrogate for the blood glucose level. The Nova StatStrip functions by using a modified glucoseoxidase-based amperometric test.2 This device also corrects for interference and hematocrit levels. Other commonly used glucometers include the Accu-Chek Performa, Countour TS, OneTouch Ultra2, and the Optium Xceed. These glucometers vary in their level of accuracy, occurrences of error messages, and influence by hematocrit levels.3
In outpatient settings, people with type 1 (T1DM) or type 2 diabetes mellitus (T2DM) monitor their blood glucose levels using a glucometer. While individuals with T1DM, an autoimmune disease that interferes with insulin production, monitor their blood glucose levels to determine their insulin dose, those with T2DM, a disease of insulin resistance, usually require closer monitoring when they are sick, exhausted, or adjusting new medication regimens. Type 1 and type 2 diabetics require similar monitoring while hospitalized with injuries or illnesses.
Blood Glucose Monitoring in Hospitals
Diabetics are not the only patients who require close monitoring of blood glucose levels. The FDA’s approval of the Nova StatStrip System for use in all hospitalized patients is relevant because so many hospitalized patients, including non diabetic patients, require blood glucose level monitoring to maintain euglycemia. Hospitalized patients are susceptible to hypo- and hyperglycemia. For example, neonatal and pediatric patients are at a particularly high risk of sustaining brain damage if they become hypoglycemic; cardiac surgery patients are at an increased risk of wound infection following prolonged hyperglycemia; and uncontrolled glucose levels in intensive care unit patients are associated with impending sepsis.
Insulin and glucose levels vary dramatically in response to infection, inflammation, injury, and other pathologies requiring hospitalization. Sustained hyperglycemia, defined as fasting glucose levels consistently above 130 mg/dL, leads to problems that mirror uncontrolled diabetes: patients experience increased inflammation, risk of infection, changes in coagulation, macrovascular and microvascular disease, and aberrations in lipid levels.4 Hypoglycemia, described as blood glucose levels below 60 mg/dL, may prove more dangerous for patients in the short term. Low blood glucose levels may lead to loss of consciousness, falls, seizures, cardiac arrhythmias, coma, and even death.
As a result of the health problems that have led to their hospitalization, patients are already highly vulnerable to endogenous fluctuations in glucose levels. In addition, once hospitalized, dietary changes and new medications can greatly influence their glucose levels. For example, patients almost always fast prior to surgery or certain procedures, and they may not eat normally for several days afterward. Consequently, hospitalized patients who are fasting preoperatively or have anorexia postoperatively are at an increased risk of hypoglycemia and hyperglycemia.
Within the hospitalized patient population, critically ill patients are particularly vulnerable to changes in blood glucose levels and often suffer from stress-induced hyperglycemia that is prolonged by long-term inflammation and subsequent infections. Medications, including steroids, can also increase blood glucose levels, while glucose-containing intravenous fluids further worsen hyperglycemia.
Healthcare providers often worry much more about the immediate risks associated with low blood glucose levels. Studies report that the range of hospital-associated hypoglycemia is 1.2% to 20%.5 Factors that can lead to hypoglycemia in hospitalized patients include underlying illness, nothing-by-mouth status, infrequent glucose monitoring, transitions of care, and complex medication regimens.6,7 Furthermore, critically ill patients are frequently intubated and/or sedated, and they cannot express subjective symptoms of hypoglycemia, increasing the possibility of a missed diagnosis. Critically ill patients are often fed intravenously or by tube feedings. The amount of glucose in the intravenous fluids, total parenteral nutrition, or tube feeds must be recalibrated based on the influence of altered gut absorption, interference with other medications, and fluid status. As adjustments are made to the nutritional support, healthcare providers must carefully readjust the insulin and glucose they administer based on the patients’ blood glucose levels.
Many critically ill patients cannot swallow oral antidiabetic agents because of the severity of their disease, renal dysfunction, fasting, or intubation. If they have dramatic swings in their blood glucose levels, they require sliding scale insulin or continuous intravenous insulin and frequent monitoring. Under these circumstances, healthcare providers may need to check the blood glucose levels of critically ill patients as often as hourly or every few hours and adjust the insulin dose to maintain euglycemia. Optimally, testing at the bedside would allow for better care than sending repeated blood draws to the laboratory for glucose analysis. But before the FDA approved the Nova StatStrip in September, no bedside glucometer had been approved for use with critically ill patients.
Traditionally, blood samples from critically ill patients have been sent to the hospital laboratory for analysis. Despite delivering the most accurate measure of blood glucose levels, it is not always safe or feasible to send all blood samples to the hospital laboratory.3 If a patient is unconscious or has altered mental status due to hypoglycemia, diagnosing hypoglycemia immediately becomes vital for the medical team, and they cannot wait for the blood sample to reach the lab. Therefore, portable glucose meters may be the safer option. Similarly, if an unstable patient is being followed with hourly blood glucose evaluation, the turnaround time for the lab to evaluate a blood sample is too long to be useful, and the amount of blood required for repeated blood draws may be too high and lead to iatrogenic anemia. As a result of these factors, healthcare providers may find that portable glucose meters, such as the Nova StatStrip, are a better choice.
The Nova StatStrip has been approved for use in neonatal and pediatric patients, as well as adult patients. Hypoglycemia in neonates can cause brain damage, and accurate diagnosis of low blood glucose levels in newborns becomes imperative.8 Studies show that the StatStrip has good clinical accuracy for measuring point-of-care glucose levels in neonatal patients, and the glucometer does not encounter interference from hematocrit, bilirubin, or maltose levels.9,10 The device also works well in assessing hypoglycemia and hyperglycemia in older children. Exhibiting a good correlation with actual blood glucose levels, StatStrip works quickly even with a small volume of blood.11
The device, now approved in critically ill patients, also meets CLSI POCT 12-A3 accuracy criteria and has decreased glucose meter bias with fewer insulin dosing discrepancies.12 The Nova StatStrip Glucose Meter has been cleared with a “waived” test status for all settings under the Clinical Laboratory Improvement Amendments, and it does not have to meet requirements for high complexity testing. Per the FDA, the device is easy to use and has low risk for false results. Therefore, healthcare professionals, including nurses and technicians, can perform the test at the patient’s bedside instead of having to send blood to the hospital laboratory for analysis.13 Additional studies suggest that the StatStrip is also a good option for glucose testing in tertiary care settings.14
In the FDA’s press announcement, Alberto Gutierrez, director of the Office of In Vitro Diagnostics and Radiological Devices at the FDA’s Center for Devices and Radiological Health, is quoted as saying, “This device provides an important public health resource for critically ill hospitalized patients, who often have conditions or are taking medications that can cause incorrect blood glucose reading. It is important for manufacturers of glucose meters used in hospitals to design and test their devices for use in all hospitalized patients.”1
The Nova StatStrip Glucose Hospital Meter System is manufactured by the Nova Biomedical Corporation located in Waltham, Massachusetts.References
1. FDA clears glucose monitoring system for use in hospital critical care units [press release]. FDA website. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm416144.htm. Published September 24, 2014.
2. Nova Multi-Well glucose StatStrip technology: publications and presentations. Nova Biomedical website. http://www.novabiomedical.com/wp-content/uploads/reports/169.pdf. Accessed October 16, 2014.
3. Robinson CS, Sharp P. Tighter accuracy standards within point-of-care blood glucose monitoring: how six commonly used systems compare. J Diabetes Sci Technol. 2012;6(3):547-554.
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10. Nuntnarumit P, Chittamma A, Pongmee P, Tangnoo A, Goonthon S. Clinical performance of the new glucometer in the nursery and neonatal intensive care unit. Pediatr Int. 2011;53(2):218-223.
11. Lockyer MG, Fu K, Edwards RM, et al. Evaluation of the Nova StatStrip glucometer in a pediatric hospital setting. Clin Biochem. 2014;47(9):840-843.
12. Karon BS, Blanshan CT, Deobald GR, Wockenfus AM. Retrospective evaluation of the accuracy of Roche AccuChek Inform and Nova StatStrip glucose meters when used on critically ill patients [published online August 5, 2014]. Diabetes Technol Ther. doi:10.1089/dia.2014.0074.
13. Nova StatStrip Glucose Hospital Meter System receives FDA clearance for intensive care use [press release]. Waltham, MA: Nova Biomedical; September 25, 2014. http://www.novabiomedical. com/nova-statstrip-glucose-hospital-meter-systemreceives-fda-clearance-for-intensive-care-use/.
14. Chan PC, Rozmanc M, Seiden-long I, Kwan J. Evaluation of a point-of-care glucose meter for general use in complex tertiary care facilities. Clin Biochem. 2009;42(10-11):1104-1112.