Arterial Catheter for Glucose Control in Critically Ill
Arterial Catheter for Glucose Control in Critically Ill
Background Use of an arterial catheter to obtain hourly blood samples for intensive insulin therapy monitoring avoids causing patients the discomfort of repeated fingersticks. Returning the clearing volume may decrease procedure-related blood loss by 50% and minimize the risk of anemia.
Objectives To compare the feasibility of 2 arterial catheter clearing-volume return setups for hourly blood extractions and to evaluate the related complications and the accuracy of arterial samples in determining glycemia.
Methods In an open clinical trial, 90 critical patients undergoing intensive insulin therapy who had a radial arterial catheter were randomized to an intervention group—nonwaste needleless setup or nonwaste syringe setup and compared with the standard setup (control group). Mechanical and infectious complications related to the arterial catheter were evaluated. Blood glucose measurements at point-of-care glucometer (arterial catheter or fingerstick sample) were compared with laboratory results (venous blood).
Results No patient had catheter-related infection in the intervention group (an estimated 12 776 manipulations); the control group had 2 infection episodes in 5230 catheter-days (an estimated 13 075 manipulations). The incidence of bacterial colonization was not significantly higher in the needleless group than in the syringe group (22.2% vs 12.2%; relative risk, 0.55; 95% CI, 0.16–1.71), with 1778 (SD, 114) and 1918 (SD, 82) catheter manipulations, respectively. Arterial catheter complications were negligible in all patients. Glycemia was detected from arterial catheter samples as effectively as with laboratory results (venous samples) except when hematocrit was less than 25%.
Conclusions Use of blood obtained via an arterial catheter is safe and effective for glucose monitoring in patients undergoing intensive insulin therapy, with no increase in complications of catheterization. (American Journal of Critical Care. 2014;23:150–159)
Intensive insulin therapy (IIT) has been implemented by intensive care units (ICUs) worldwide. In clinical practice, this rapid intravenous perfusion of insulin to maintain an optimal glycemia target of 110 to 140 mg/dL requires hourly glycemia monitoring, often relying on fingerstick sampling. Fingersticks, which can be painful for the patient, may yield unreliable glycemic values when a point-of-care (POC) glucometer with capillary sampling is used. Although the POC glucometer is of particular concern in patients with anemia, it has been used in numerous studies. In critically ill patients, pressure-monitoring systems connected to indwelling arterial catheters also allow repeated extraction of blood samples. Although this avoids the discomfort associated with fingersticks, it is not exempt from complications and the daily loss of 40 to 70 mL of blood. Increased handling of arterial catheters and access to the connections several times a day increases the risk of infection (0.31–3.36 x 1000 catheter-days), obstruction (11%-29%), and other local complications (eg, arterial thrombosis [4.6%-19.7%], finger or hand ischemia [0.09%], and pseudoaneurysm [0.09%]).
In 2001, only 8% of ICUs in England were reintroducing the clearing volume via an arterial catheter; as of 2012, researchers reported that fewer than half (41%) of Australian operating theaters had implemented this practice, despite the availability of reports that it cuts blood loss in half and decreases the need for transfusion. Commercially available, closed blood-conservation devices (eg, Edwards VAMP Plus System, SafeSet Blood Sampling System [ICU Medical, Inc], Edwards VAMP System) that allow reinfusion of the clearing volume can be impractical for hourly use because they require pushing high volumes (5–12 mL) through the full length of the arterial tubing or do not have a Lueractivated needle-free valve that minimizes fibrin clot formation. All of these devices require manual return of the clearing volume, followed by fast flush of the continuous flushing system. Kaye et al demonstrated that flushing modality (manual vs continuous flushing) and clearing-volume return did not interfere with permeability of arterial catheters.
The objective of this study was to compare 2 designs for arterial catheter setup used in IIT patients for hourly blood sampling, assess complications, and determine whether arterial samples are effective for detecting glycemia compared with gold-standard laboratory analysis.
Abstract and Introduction
Abstract
Background Use of an arterial catheter to obtain hourly blood samples for intensive insulin therapy monitoring avoids causing patients the discomfort of repeated fingersticks. Returning the clearing volume may decrease procedure-related blood loss by 50% and minimize the risk of anemia.
Objectives To compare the feasibility of 2 arterial catheter clearing-volume return setups for hourly blood extractions and to evaluate the related complications and the accuracy of arterial samples in determining glycemia.
Methods In an open clinical trial, 90 critical patients undergoing intensive insulin therapy who had a radial arterial catheter were randomized to an intervention group—nonwaste needleless setup or nonwaste syringe setup and compared with the standard setup (control group). Mechanical and infectious complications related to the arterial catheter were evaluated. Blood glucose measurements at point-of-care glucometer (arterial catheter or fingerstick sample) were compared with laboratory results (venous blood).
Results No patient had catheter-related infection in the intervention group (an estimated 12 776 manipulations); the control group had 2 infection episodes in 5230 catheter-days (an estimated 13 075 manipulations). The incidence of bacterial colonization was not significantly higher in the needleless group than in the syringe group (22.2% vs 12.2%; relative risk, 0.55; 95% CI, 0.16–1.71), with 1778 (SD, 114) and 1918 (SD, 82) catheter manipulations, respectively. Arterial catheter complications were negligible in all patients. Glycemia was detected from arterial catheter samples as effectively as with laboratory results (venous samples) except when hematocrit was less than 25%.
Conclusions Use of blood obtained via an arterial catheter is safe and effective for glucose monitoring in patients undergoing intensive insulin therapy, with no increase in complications of catheterization. (American Journal of Critical Care. 2014;23:150–159)
Introduction
Intensive insulin therapy (IIT) has been implemented by intensive care units (ICUs) worldwide. In clinical practice, this rapid intravenous perfusion of insulin to maintain an optimal glycemia target of 110 to 140 mg/dL requires hourly glycemia monitoring, often relying on fingerstick sampling. Fingersticks, which can be painful for the patient, may yield unreliable glycemic values when a point-of-care (POC) glucometer with capillary sampling is used. Although the POC glucometer is of particular concern in patients with anemia, it has been used in numerous studies. In critically ill patients, pressure-monitoring systems connected to indwelling arterial catheters also allow repeated extraction of blood samples. Although this avoids the discomfort associated with fingersticks, it is not exempt from complications and the daily loss of 40 to 70 mL of blood. Increased handling of arterial catheters and access to the connections several times a day increases the risk of infection (0.31–3.36 x 1000 catheter-days), obstruction (11%-29%), and other local complications (eg, arterial thrombosis [4.6%-19.7%], finger or hand ischemia [0.09%], and pseudoaneurysm [0.09%]).
In 2001, only 8% of ICUs in England were reintroducing the clearing volume via an arterial catheter; as of 2012, researchers reported that fewer than half (41%) of Australian operating theaters had implemented this practice, despite the availability of reports that it cuts blood loss in half and decreases the need for transfusion. Commercially available, closed blood-conservation devices (eg, Edwards VAMP Plus System, SafeSet Blood Sampling System [ICU Medical, Inc], Edwards VAMP System) that allow reinfusion of the clearing volume can be impractical for hourly use because they require pushing high volumes (5–12 mL) through the full length of the arterial tubing or do not have a Lueractivated needle-free valve that minimizes fibrin clot formation. All of these devices require manual return of the clearing volume, followed by fast flush of the continuous flushing system. Kaye et al demonstrated that flushing modality (manual vs continuous flushing) and clearing-volume return did not interfere with permeability of arterial catheters.
The objective of this study was to compare 2 designs for arterial catheter setup used in IIT patients for hourly blood sampling, assess complications, and determine whether arterial samples are effective for detecting glycemia compared with gold-standard laboratory analysis.