Background

Intensive insulin treatment is associated with an increased risk of hypoglycemia, so strict glycemic monitoring is essential. The best type of sample for identifying hypoglycemia remains under debate.

Objectives

To establish the number of hypoglycemic events in intensive care patients relative to insulin administration method and the method used to collect the blood sample.

Methods

Retrospective descriptive study lasting 6 months. Hypoglycemia was defined as a blood glucose level less than 80 mg/dL (mild: 50–79 mg/dL, severe: <50 mg/dL), measured with a bedside glucometer and blood from the arterial catheter or fingerstick, in critically ill patients who require insulin administered subcutaneously (with sliding scales) or via continuous intravenous perfusion (intense infusion protocol with a nurse-managed insulin therapy algorithm).

Results

Analysis of the 6636 samples from 144 critically ill patients revealed 188 mildly hypoglycemic samples (2.8%) and 3 severely hypoglycemic samples (0.04%). The prevalence of mild hypoglycemia was greater when insulin was administered intravenously (3.2%) rather than subcutaneously (2.3%; P = .04). Among patients receiving insulin intravenously, hypoglycemia was found more often in arterial (4.5%) than in capillary (2.8%) blood (P = .01). The prevalence of hypoglycemia in capillary blood samples did not differ significantly between subcutaneous (2.3%) and intravenous (2.8%) insulin therapies (P = .21).

Conclusions

With a target blood glucose level of 110 to 140 mg/dL, few hypoglycemic events are detected in critically ill patients, regardless of whether insulin is administered intravenously or subcutaneously. Analysis of solely arterial samples may yield a higher prevalence of hypoglycemia than otherwise.

Scientific societies1,2  recommend strict control of glycemia in critically ill patients because of the clear association of such control with reduced morbidity and mortality in these patients.38  Nonetheless, various studies915  have shown a greater incidence of hypoglycemia when patients receive intensive insulin therapy via a continuous insulin infusion protocol (IIP).

In a meta-analysis of 29 studies (8432 patients), Wiener et al16  assessed the risk/benefit factor of tight glucose control in critically ill patients and was able to draw a clear conclusion: the incidence of hypoglycemia was higher among patients receiving intensive insulin therapy, and the increase in incidence was in proportion to the tightness of the glucose control. In 2 later studies,7,13  hypoglycemia was associated with mortality as an independent factor. In addition, in an international clinical trial, Normoglycemia in Intensive Care Evaluation Survival Using Glucose Algorithm Regulation (NICE-SUGAR),17  investigators found more deaths from cardiovascular causes and more episodes of hypoglycemia (<40 mg/dL; to convert to millimoles per liter, multiply by 0.055) in the IIP group and concluded that hypoglycemia might simply be a strong marker of illness severity.

In a subsequent consensus statement on inpatient glycemic control, the American Association of Clinical Endocrinologists and the American Diabetes Association18  recommended use of an IIP to control hyperglycemia in intensive care unit (ICU) patients, with the protocol to begin being used when glucose values are close to 180 mg/dL, maintaining an optimum range between 140 and 180 mg/dL.

Published analyses to date do not differentiate by the type of blood sample used for analysis of glucose level. The objective of the present study was to assess the number of hypoglycemic events found in ICU patients according to the type of sample analyzed (fingerstick or arterial blood), as well as the type of rapid insulin administration used (subcutaneous or intravenous).

Materials and Methods

The retrospective study included glycemia tests of ICU patients hospitalized between April 1 and September 30, 2008. Patients studied were in a multipurpose 10-bed ICU that serves all medical and surgical specialties except cardiac, thoracic, and neurological cases.

Our IIP was based on the Yale insulin infusion protocol.19  Therefore, hypoglycemia was considered as a blood glucose level less than 80 mg/dL, with a value of 50 to 80 mg/dL categorized as mild hypoglycemia and less than 50 mg/dL as severe hypoglycemia20,21  because our IIP requires intravenous insulin at this value to prevent the neurological complications associated with hypoglycemia, even if the patient is asymptomatic.

The incidence of hypoglycemia is higher in patients receiving intensive insulin therapy.

In our standard protocol, used in this study, an Optium Xceed glucometer (Abbott Diabetes Care, MediSense Products, Doncaster, Australia) calibrated per manufacturer instructions is assigned to each patient, and strips appropriate to that calibration are documented and kept in that patient’s box of supplies in the ICU. Our unit requires 3 point-of-care measurements to confirm hypoglycemia. When the glycemia measurement is less than 80 mg/dL, the measurement is repeated twice with the same glucometer but with 2 different samples, to ensure against any error in the fingerstick technique or in reading the glucometer.

Two insulin therapy protocols were used: (1) the unit’s normal standard, under which patients with a blood glucose level less than 180 mg/dL receive subcutaneous rapid insulin, with blood glucose level checked every 6 hours and insulin administered according to a predefined sliding scale of blood glucose levels) and (2) intravenous insulin therapy following a new IIP in the unit that uses dynamic scales (perfusion velocity adjusted as the blood glucose level changes), administered for patients with blood glucose levels greater than 180 mg/dL or patients with a blood glucose level greater than 150 mg/dL who meet at least 1 of the following clinical criteria: sepsis with failure of 2 or more organs, invasive mechanical ventilation for more than 5 days and insulin-dependent diabetes.2,22  Briefly, those protocols are defined as follows:

  • Sliding-scale protocol: blood collection at 6-hour intervals. With subcutaneous administration of insulin, blood samples for glucose testing are collected via fingerstick because these patients do not have an arterial catheter. The guideline for subcutaneous administration of insulin is every 6 hours, and therefore our protocol requires testing of blood glucose level at 6-hour intervals; more frequent sampling (as in IIP patients, next) would reflect the therapeutic effect of the previously administered dose of insulin.

    About 62% of hypoglycemias occurred with insulin infusion; 38%, with subcutaneous insulin therapy.

  • IIP with dynamic scales: hourly blood collection. Whether the sample is obtained from the arterial catheter (first 48 hours) or finger-stick (thereafter), more frequent monitoring is required to determine the speed with which intravenously administered insulin is infused, depending on the blood glucose level measured. Before the arterial sample is collected for analysis, 2 mL of diluted blood is discharged from the dead space of the arterial catheter.

The therapeutic protocols were interchangeable throughout the study period: if a patient receiving 1 treatment met the criteria for the other, the treatment was changed (see Figure 1). The therapeutic objective for subcutaneous insulin therapy was to maintain a blood glucose level of 180 mg/dL or less; the IIP objective was to achieve a blood glucose level within a range of 110 to 140 mg/dL. The same type of insulin (Aspart, Novo Nordisk A/S, Copenhagen, Denmark) was administered, whether subcutaneously or intravenously.

Clinical histories were included for patients with at least 4 blood glucose measurements recorded per day, whether from capillary or arterial blood. Patients were excluded if they had sustained hypoglycemia for 4 hours or longer despite discontinuation of the intravenous insulin therapy.

The variables analyzed were blood glucose values (in milligrams per deciliter) measured in arterial or capillary blood samples from patients treated with intensive IIP and capillary samples of patients treated with subcutaneous insulin.

All patients included in the study, or their guardians, provided informed consent, and the protocol was approved by the hospital’s Committee on Ethics and Clinical Research.

Statistical Analysis

SPSS version 16.0 (SPSS, Inc, Chicago, Illinois) was used for statistical analysis. A χ2 test was used to compare differences in the incidence of hypoglycemia between different groups. A P value less than .05 is considered statistically significant. Data are presented either as a mean (SD) or as a percentage.

Results

Of 144 patients admitted to the ICU during the study period who required insulin therapy, 44 patients were excluded (42 had an insufficient number of recorded blood glucose levels [<4 per day] and 2 had sustained hypoglycemia for more than 4 consecutive hours despite suspension of the IIP perfusion). For the 100 patients included, 6636 glycemia tests were available for analysis.

Most of the included patients (74%) had a blood glucose level less than 180 mg/dL with subcutaneous insulin and did not meet the criteria for inclusion in the IIP group (see Figure 1). However, under the dynamic therapeutic protocol, 21% received both subcutaneous and intravenous insulin at different points in their ICU stay, in general requiring intravenous insulin therapy during the most serious period of the problem for which they were hospitalized. Only 5% received intravenous insulin exclusively.

The mean (SD) age of the study participants was 66.4 (17.5) years, 67% were male, and the mean (SD) score on the Acute Physiology and Chronic Health Evaluation (APACHE) II at admission was 16.3 (7.4). Diagnoses on admission to the ICU included sepsis (30.9%), heart disease (24.7%), acute respiratory failure (15.9%), postoperative monitoring referred by surgical specialties (10.6%), hepatopancreatic abnormalities (7.1%), and medication imbalance (4.4%). Diabetes was diagnosed in 22% of study participants.

Of the hypoglycemias detected, 62.1% were from patients being treated with intravenous insulin therapy when the sample was collected and 37.9% were from patients receiving subcutaneous insulin therapy when the sample was collected. Patients treated with intravenous insulin therapy showed a mean (SD) blood glucose level of 150.6 (54.5) mg/dL, and patients receiving subcutaneous insulin therapy had a mean (SD) blood glucose level of 153.3 (50.2) mg/dL (Figure 2).

Categorical analysis of the blood glucose measurements by insulin administration protocol is detailed in Figure 3. In the case of intravenous insulin therapy, we observed a trend toward lower values (<110 mg/dL) at the expense of high values (>140 mg/dL), although this difference was not statistically significant.

We detected 188 (2.8%) mild hypoglycemic events (130 in the intravenous group and 58 in the subcutaneous group; 3.2% vs 2.3%; P = .04). The 58 mild hypoglycemic events in the subcutaneous group were spread across the 74 patients treated with subcutaneous insulin only (APACHE score: mean, 14.4; SD, 7.03). The 130 hypoglycemic events in the intravenous group were split between 109 events (83.8%) in 21 patients who alternated between both protocols (APACHE score: mean, 15.6; SD, 7.01) and only 21 events (16.2%) in 5 patients treated exclusively with intravenous insulin (APACHE score: mean, 28; SD, 3.03), of which 18 hypoglycemic events were detected in capillary samples and 3 hypoglycemic events were detected in arterial samples.

Of the 130 hypoglycemic events in patients receiving insulin intravenously, 35 hypoglycemic events were detected in 771 arterial blood samples and only 95 events were detected in the 3353 capillary blood samples, resulting in a significant difference (4.5% vs 2.8%, P = .01). In capillary samples, obtained by fingerstick, the numbers of hypoglycemic events detected did not differ between patients receiving subcutaneous insulin therapy (2.3%) and patients receiving intravenous insulin therapy (2.8%; P = .21, see Table). Severe hypoglycemic events were detected in just 3 samples (0.04%), 2 of these in capillary samples from patients receiving intravenous insulin therapy and the third in a capillary sample from a patient receiving subcutaneous insulin therapy.

Discussion

The number of mild hypoglycemias was slightly higher in patients receiving intravenous insulin therapy than in patients receiving subcutaneous insulin, which makes sense if one considers the stricter therapeutic objective in patients treated intravenously. However, the use of infusion protocols with demonstrated safety and efficacy results in the detection of low levels of hypoglycemia.18  In our ICU, the objective is to achieve blood glucose levels of 110 to 140 mg/dL, a bit higher than the target values initially recommended, because the literature suggests that intensive insulin therapy with lower target levels for blood glucose is associated with a higher incidence of hypoglycemic events and only scant improvement in morbidity and mortality.7,23  Our unit has chosen a target blood glucose level for patients receiving intravenous insulin therapy that is within the recommended guidelines of the American Association of Clinical Endocrinologists and the American Diabetes Association in their consensus statement on inpatient glycemic control.18 

Capillary blood glucose values are higher than the corresponding arterial blood values.

Our findings concur with results of other studies in which different blood glucose ranges were compared, whether in a comparison of subcutaneous insulin therapy and IIP24,25  or between 2 IIPs with different ranges.6,7,12,13,15,17 

Other than our study, we found only 6 studies14,19,22,24,26,27  in which mild hypoglycemic events were analyzed. In most clinical trials,6,7,10,12,13,17  only severe hypoglycemia is considered. The defining value of hypoglycemia varies in these studies, which makes comparisons difficult. Braithwaite et al26  reported a 2.4% incidence of hypoglycemias less than 70 mg/dL and did not find any hypoglycemic events less than 50 mg/dL. Bland et al22  reported a 2.1% incidence of moderate hypoglycemia (40–60 mg/dL) in the group treated with intensive insulin therapy, and a 0.1% incidence of severe hypoglycemias, very similar to our results in both cases. Goldberg et al19  also obtained similar results (0.2% hypoglycemia <70 mg/dL), whereas Osburne et al27  reported a 6.9% incidence of hypoglycemia in the 60 to 80 mg/dL range and only a 0.9% incidence for hypoglycemia less than 60 mg/dL. In all of these studies, and in our study, percentages were calculated against the total number of samples taken. In other studies14,17  in which slight hypoglycemia was assessed, researchers calculated the incidence on the basis of the number of patients who had at least 1 hypoglycemic episode. With respect to severe hypoglycemia, published clinical trials have reported frequencies of 5% to 18%, much higher than our findings, as reflected in a meta-analysis done after NICE-SUGAR was completed.28 

The differences in results may be attributable to differences in methods.20,29  In addition, despite having a similar study protocol, different centers in other clinical trials had different routines for sampling and analysis of blood glucose levels10,17,30,31  or considered capillary and arterial blood samples to be interchangeable for purposes of analysis.12,13,20,21,31,32  Our study addresses this gap in the literature by comparing blood glucose determinations on the basis of the type of sample analyzed. Differences between the 2 groups were found only when we included arterial samples in the analysis (as in the previous studies). This finding could have important implications in treating critically ill patients because it supports studies such as those by Scott et al,32  Lacara et al,33  and Slater-MacLean et al,34  who found that capillary blood glucose values were higher than the corresponding arterial blood glucose values, and NICE-SUGAR,17  which recommended against use of fingerstick samples for analysis of blood glucose levels.

With respect to sampling procedures, the literature establishes that blood glucose values obtained from fingerstick samples result in overestimates of blood glucose level in comparison with “reference standard” laboratory techniques.33,3538  Bedside glucometer readings in critically ill patients result in overestimates of blood glucose level3942  and lack precision2,18,32,34,43  for a variety of reasons: fluid accumulation in the fingertips, poor peripheral perfusion due to shock or administration of vasopressors, anemia, sample volume insufficient for analysis, or sampling method used.20  In addition, glucometers must be calibrated frequently, but such calibration may be neglected in clinical practice. In our study, each patient was provided with a box of supplies that included the patient’s assigned Optium-Xceed glucometer, calibrated per the manufacturer’s instructions,44  and strips appropriate to that calibration; if additional strips were needed and came from a different lot, the glucometer was recalibrated.

Limitations of this study include its retrospective, observational design and the fact that the samples are not simultaneous in these critically ill patients. Case-control studies are needed to verify that the results obtained are not the result of any clinical and/or metabolic instability in the included patients. In addition, under our standard clinical protocol, the hypoglycemia readings were confirmed by repeated measurements with point-of-care devices rather than by control laboratory measurements.

Even though blood samples were collected from arterial catheters hourly, discarding 2 mL of diluted blood each time (which was returned to the patient’s circulatory flow to avoid iatrogenic anemia), little has been published about arterial catheter sampling techniques that do not increase collateral effects such as anemia, infection, and ischemia/pseudoaneurysm of the radial artery. The complications of hypoglycemia move researchers to search for systems with higher sensitivity and specificity to detect hypoglycemia. In this sense, our group is conducting a clinical trial to determine whether the use of an arterial catheter permits more precise monitoring of glycemia, as this system offers the important advantage of avoiding the hourly fingersticks that produce discomfort for both patients and nurses.19,22,45 

Conclusions

With a target for blood glucose level of 110 to 140 mm Hg, the number of hypoglycemic events detected in critically ill patients is low, regardless of the type of administration of insulin therapy (intravenous IIP with a nurse-managed insulin therapy algorithm or subcutaneous with sliding scales). Nonetheless, a higher incidence of hypoglycemias less than 80 mg/dL was detected in arterial than capillary blood samples with a bedside glucometer. Therefore, if only arterial samples are analyzed in critically ill patients, the incidence of hypoglycemias could be higher than if capillary and arterial samples are used.

ACKNOWLEDGMENTS

We thank the ICU nursing team for their collaboration in collecting arterial blood samples according to the study protocol. The authors appreciate the English language review by Elaine Lilly, phd.

REFERENCES

REFERENCES
1
ACE/ADA Task Force on Inpatient Diabetes
.
American College of Endocrinology and American Diabetes Association consensus statement on inpatient diabetes and glycemic control
.
Endocr Pract.
2006
;
12
:
458
468
.
2
Dellinger
RP
,
Levy
MM
,
Carlet
JM
, et al
.
Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008
.
Crit Care Med.
2008
;
36
(
1
):
296
327
.
3
Furnary
AP
,
Zerr
KJ
,
Grunkemeier
GL
,
Starr
A
.
Continuous intravenous insulin infusion reduces the incidence of deep sternal wound infection in diabetic patients after cardiac surgical procedures
.
Ann Thorac Surg.
1999
;
67
:
352
360
.
4
Capes
SE
,
Hunt
D
,
Malmberg
K
, et al
.
Stress hyperglycemia and prognosis of stroke in nondiabetic and diabetic patients: a systematic overview
.
Stroke.
2001
;
32
:
2426
2432
.
5
Pittas
AG
,
Siegel
RD
,
Lau
J
.
Insulin therapy for critically ill hospitalized patients: a meta-analysis of randomized, controlled trials
.
Arch Intern Med.
2004
;
164
(
18
):
2005
2011
.
6
Van den Berghe
G
,
Wouters
P
,
Weekers
F
, et al
.
Intensive insulin therapy in critically ill patients
.
N Engl J Med.
2001
;
345
:
1359
1367
.
7
Van den Berghe
G
,
Wilmer
A
,
Hermans
G
, et al
.
Intensive insulin therapy in the medical ICU
.
N Engl J Med.
2006
;
354
:
449
461
.
8
Schetz
M
,
Vanhorebeek
I
,
Wouters
PJ
,
Wilmer
A
,
Van den Berghe
G
.
Tight blood glucose control is renoprotective in critically ill patients
.
J Am Soc Nephrol.
2008
;
19
(
3
):
571
578
.
9
Angus
DC
,
Abraham
E
.
Intensive insulin therapy in critical illness
.
Am J Respir Crit Care Med.
2005
;
172
(
11
):
1358
1359
.
10
Malmberg
K
,
Rydén
L
,
Wedel
H
, et al
.
Intense metabolic control by means of insulin in patients with diabetes mellitus and acute myocardial infarction (DIGAMI 2): effects on mortality and morbidity
.
Eur Heart J.
2005
;
26
:
650
661
.
11
Treggiari
MM
,
Karir
V
,
Yanez
ND
,
Weiss
NS
,
Daniel
S
,
Deem
SA
.
Intensive insulin therapy and mortality in critically ill patients
.
Crit Care.
2008
;
12
(
1
):
R29
.
12
De la Rosa
GD
,
Donado
JH
,
Restrepo
AH
, et al
.
Strict glycaemic control in patients hospitalised in a mixed medical and surgical intensive care unit: a randomised clinical trial
.
Crit Care.
2008
;
12
(
5
):
R120
.
13
Brunkhorst
FM
,
Engel
C
,
Bloos
F
, et al
.
Intensive insulin therapy and pentastarch resuscitation in severe sepsis
.
N Engl J Med.
2008
;
358
(
2
):
125
139
.
14
Egi
M
,
Bellomo
R
,
Stachowski
E
, et al
.
Hypoglicemia and outcome in critically ill patients
.
Mayo Clin Proc.
2010
;
85
(
3
):
217
224
.
15
Arabi
YMM
,
Tamim
H
,
Rishu
A
.
Hypoglycemia with intensive insulin therapy in critically ill patients: predisposing factors and association with mortality
.
Crit Care Med
.
2009
;
37
:
2536
2544
.
16
Wiener
RS
,
Wiener
DC
,
Larson
RJ
.
Benefits and risks of tight glucose control in critically ill adults: a meta-analysis
.
JAMA.
2008
;
300
(
8
):
933
944
.
17
Finfer
S
,
Chittock
DR
,
Su
SY
, et al
.
Intensive versus conventional glucose control in critically ill patients. The NICE-SUGAR Study Investigators
.
N Engl J Med.
2009
;
360
(
13
):
1283
1297
.
18
Moghissi
E
,
Korytkowski
M
,
DiNardo
M
,
Einhorn
D
,
Hellman
R
,
Hirsch
I
.
American Association of Clinical Endocrinologists and American Diabetes Association Consensus Statement on Inpatient Glycemic Control
.
Diabetes Care.
2009
;
32
(
6
):
1119
1131
.
19
Goldberg
PA
,
Siegel
MD
,
Sherwin
RS
,
Halickman
JI
,
Lee
M
,
Bailey
VA
.
Implementation of a safe and effective insulin infusion protocol in a medical intensive care unit
.
Diabetes Care.
2004
;
27
:
461
467
.
20
Adams
G
,
Hunter
J
,
Langley
J
.
Is nurse-managed blood glucose control in critical care as safe and effective as the traditional sliding scale method?
Intensive Crit Care Nurs.
2009
;
25
(
6
):
294
305
.
21
Meijering
S
,
Corstjens
A
,
Tulleken
J
,
Meertens
J
,
Zijlstra
J
,
Ligtenberg
J
.
Towards a feasible algortihm for tight glycaemic control in critically ill patients: a systematic review of the literature
.
Crit Care.
2006
;
10
:
R19
.
22
Bland
D
,
Fankhanel
Y
,
Langford
E
,
Lee
M
,
Lee
S
,
Maloney
C
.
Intensive versus modified conventional control of blood glucose level in medical intensive care patients: a pilot study
.
Am J Crit Care.
2005
;
14
:
370
376
.
23
Vincent
JL
.
Evidence-based medicine in the ICU: important advances and limitations
.
Chest.
2004
;
126
(
2
):
592
600
.
24
Chant
C
,
Wilson
G
,
Friedrich
JO
.
Validation of an insulin infusion nomogram for intensive glucose control in critically ill patients
.
Pharmacotherapy.
2005
;
25
(
3
):
352
359
.
25
Smith
A
,
Udekwu
P
,
Biswas
S
, et al
.
Implementation of a nurse-driven intensive insulin infusion protocol in a surgical intensive care unit
.
Am J Health-System Pharm.
2007
;
64
(
14
):
1529
1540
.
26
Braithwaite
SS
,
Edkins
R
,
Macgregor
KL
, et al
.
Performance of a dose-defining insulin infusion protocol among trauma service intensive care unit admissions
.
Diabetes Technol Ther.
200
;
8
(
4
):
476
488
.
27
Osburne
R
,
Cook
C
,
Stockton
L
, et al
.
Improving hyperglycemia management in the intensive care unit: preliminary report of a nurse-driven quality improvement project using a redesigned insulin infusion algorithm
.
Diabetes Educ.
2006
;
32
:
394
403
.
28
Griesdale
DE
,
de Souza
RJ
,
Van Dam
RM
, et al
.
Intensive insulin therapy and mortality among critically ill patients: a meta-analysis including NICE-SUGAR study data
.
CMJA.
2009
;
180
(
8
):
821
827
.
29
Gunst
J
,
Van den Berghe
G
.
Blood glucose control in the intensive care unit: benefits and risks
.
Semin Dial.
2010
;
23
(
2
):
157
163
.
30
Merz
TM
,
Finfer
S
.
Intensive insulin treatment
.
Minerva Anestesiol.
2009
;
75
(
12
):
703
709
.
31
Anabtawi
A
,
Hurst
M
,
Titi
M
,
Patel
S
,
Palacio
C
,
Rajamani
K
.
Incidence of hypoglycemia with tight glycemic control protocols: a comparative study
.
Diabetes Technol Ther.
2010
;
12
(
8
):
635
639
.
32
Scott
MG
,
Bruns
DE
,
Boyd
JC
,
Sacks
DB
.
Tight glucose control in the intensive care unit: are glucose meters up to the task?
Clin Chem.
2009
;
55
(
1
):
18
20
.
33
Lacara
T
,
Domagtoy
C
,
Lickliter
D
, et al
.
Comparison of point-of-care and laboratory analysis methods in critically ill patients
.
Am J Crit Care.
2007
;
6
(
4
):
336
346
.
34
Slater-MacLean
L
,
Cembrowski
G
,
Chin
D
, et al
.
Accuracy of glycemic measurements in the critically ill
.
Diabetes Technol Ther.
2008
;
10
(
3
):
169
177
.
35
Kanji
S
,
Buffie
J
,
Hutton
B
, et al
.
Reliability of point-of-care testing for glucose measurement in critically ill adults
.
Crit Care Med.
2005
;
33
(
12
):
2778
2785
.
36
Petersen
JR
,
Graves
DF
,
Tacker
DH
,
Okorodudu
AO
,
Mohammad
AA
,
Cardenas
VJ
Jr
.
Comparison of POCT and central laboratory blood glucose results using arterial, capillary, and venous samples from MICU patients on a tight glycemic protocol
.
Clin Chim Acta.
2008
;
396
(
1–2
):
10
13
.
37
Kulkarni
A
,
Saxena
M
,
Price
G
.
Analysis of blood glucose measurements using capillary and arterial blood samples in intensive care patients
.
Intensive Care Med.
2005
;
31
(
1
):
142
145
.
38
Critchell
C
,
Callahan
A
,
Aboud
C
,
Jabbour
S
,
Marik
PE
.
Accuracy of bedside capillary blood glucose measurements in critically ill patients
.
Intensive Care Med.
2007
;
33
:
2079
2084
.
39
Arias-Rivera
S
,
Copete-Vega
A
,
Vadillo-Obesso
P
, et al
.
Reliability of the measurement of glucose at the bedside of critical patients
.
Enferm Intensiva.
2007
;
18
(
1
):
15
24
.
40
Cook
A
,
Laughlin
D
,
Moore
M
, et al
.
Differences in glucose values obtained from point-of-care glucose meters and laboratory analysis in critically ill patients
.
Am J Crit Care.
2009
;
18
(
1
):
65
72
.
41
Prinzing
C
,
Rosenlund
S
,
Sikeena
V
,
Malinowski
C
,
Wise
LC
.
Precision-to-tolerance capability: an important consideration in tight glucose control
.
Am J Crit Care.
2009
;
18
(
3
):
232
9
.
42
Pidcoke
HF
,
Wade
CE
,
Mann
EA
, et al
.
Anemia causes hypoglycemia in intensive care unit patients due to error in single-channel glucometers: methods of reducing patient risk
.
Crit Care Med.
2010
;
38
(
2
):
471
476
.
43
Krumberger
J
.
Endocrine system
. In:
Chulay
M
,
Burns
S
, eds.
AACN Essentials of Critical Care Nursing
.
New York, NY
:
McGraw-Hill
;
2006
:
357
369
.
44
Optimum Xceed Monitor
.
133–221 Xceed User Manual G3b Aus 17/03/2005
.
Doncaster, Australia
:
Abbott Diabetes Care
;
2005
.
45
Aragon
D
.
Evaluation of nursing work effort and perceptions about blood glucose testing in tight glycemic control
.
Am J Crit Care.
2006
;
15
(
4
):
370
377
.

Footnotes

FINANCIAL DISCLOSURES

This project was funded in part by the Third Fellowship in Health Sciences awarded by the Caixa de Manlleu Foundation, Barcelona, Spain.

eLetters

Now that you’ve read the article, create or contribute to an online discussion on this topic. Visit www.ajcconline.org and click “Respond to This Article” in either the full-text or PDF view of the article.

To purchase electronic or print reprints, contact The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Phone, (800) 899-1712 or (949) 362-2050 (ext 532); fax, (949) 362-2049; e-mail, reprints@aacn.org.