Mark J. Rice

Multisite, multivendor validation of the accuracy and reproducibility of proton-density fat-fraction quantification at 1.5T and 3T using a fat–water phantom

To evaluate the accuracy and reproducibility of quantitative chemical shift‐encoded (CSE) MRI to quantify proton‐density fat‐fraction (PDFF) in a fat–water phantom across sites, vendors, field strengths, and protocols.

PRIDE Statement on the Need for a Moratorium on the CMS Plan to Cite Hospitals for Performing Point-of-Care Capillary Blood Glucose Monitoring on Critically Ill Patients

OBJECTIVE A writing committee of the Planning Research in Inpatient Diabetes (PRIDE) group has written this consensus article on behalf of the group in response to a specific request for input from the Centers for Medicare and Medicaid Services (CMS). The purpose of this article is to respond to the March 13, 2015 statement from that agency regarding plans to enforce prohibition of the off-label use of point of care (POC) capillary blood glucose monitor (BGM) testing in most critically ill patients. The article discusses: 1) how POC BGM testing is currently regulated; 2) how POC BGM testing is currently used in the United States; and 3) how POC BGM testing can be safely and effectively regulated in the future through cooperation between the clinician, laboratory, regulatory, industry, and patient communities. PARTICIPANTS Nine members of PRIDE volunteered to write the statement on behalf of the entire group. EVIDENCE Descriptions of current medical practice for critically ill patients were derived from the experience of the authors. Descriptions of the performance of various methods for measuring glucose levels for intensive insulin therapy came from a literature review. CONSENSUS PROCESS Eleven questions were developed by the PRIDE writing group. After extensive electronic and telephone discussion, the article was written and reviewed by all nine authors and then reviewed by two outside experts in the care of critically ill patients. All suggestions by the authors and the outside experts were incorporated. CONCLUSIONS Although the CMS is attempting to protect patients with abnormal glycemic control from harm due to inaccurate POC fingerstick capillary BGM testing, their plan will result in more harm than good. A moratorium on enforcement of the prohibition of off-label use of POC capillary BGM testing is needed.

Blood Gas Analyzer Accuracy of Glucose Measurements

Objective: To investigate the comparability of glucose levels measured with blood gas analyzers (BGAs) and by central laboratories (CLs). Material and Methods: Glucose measurements obtained between June 1, 2007, and March 1, 2016, at the Vanderbilt University Medical Center were reviewed. The agreement between CL and BGA results were assessed using Bland‐Altman, consensus error grid (CEG), and surveillance error grid (SEG) analyses. We further analyzed the BGAs’ performance against the US Food and Drug Administration (FDA) 2014 draft guidance and 2016 final guidance for blood glucose monitoring and the International Organization for Standardization (ISO) 15197:2013 standard. Results: We analyzed 2671 paired glucose measurements, including 50 pairs of hypoglycemic values (1.9%). Bland‐Altman analysis yielded a mean bias of −3.1 mg/dL, with 98.1% of paired values meeting the 95% limits of agreement. In the hypoglycemic range, the mean bias was −0.8 mg/dL, with 100% of paired values meeting the 95% limits of agreement. When using CEG analysis, 99.9% of the paired values fell within the no risk zone. Similar results were found using SEG analysis. For the FDA 2014 draft guidance, our data did not meet the target compliance rate. For the FDA 2016 final guidance, our data partially met the target compliance rate. For the ISO standard, our data met the target compliance rate. Conclusion: In this study, the agreement for glucose measurement between common BGAs and CL instruments met the ISO 2013 standard. However, BGA accuracy did not meet the stricter requirements of the FDA 2014 draft guidance or 2016 final guidance. Fortunately, plotting these results on either the CEG or the SEG revealed no results in either the great or extreme clinical risk zones.

An Evaluation of the State of Neuromuscular Blockade Monitoring Devices

A core element of anesthesia care is the use of intravenous muscle relaxants. While neuromuscular blockade (NMB) monitoring devices assess the degree of patient paralysis, few clinically convenient monitors exist. The lack of ergonomic NMB monitors results in inefficient dosing and patient morbidity. An analysis of challenges associated with NMB monitoring, as well as strengths and weaknesses of current noninvasive monitoring techniques, is presented as a foundation for the development of new NMB monitoring devices. NMB agents provide ideal conditions for tracheal intubation and prevent intraoperative patient movement. However, improper dosing and maintenance of the level of NMB can result in residual paralysis, pneumonia, and aspiration [1]. Objective monitoring provides metrics for clinicians to monitor levels of NMB agents accurately and in real time. Objective monitoring can help clinicians determine safe intubation and extubation times, check qualification for acetylcholinesterase inhibitors for effective paralysis reversal, and provide metrics to determine proper dosing maintenance during surgery. Train-of-four (TOF) stimulation is the most common pattern used to objectively monitor neuromuscular function. In TOF pattern stimulation, four stimuli are delivered via nerve stimulator at 2 Hz over a period of 2 s [2]. The ratio of fourth twitch to first twitch, or TOF ratio, can be calculated subjectively with touch or sight, or with an objective monitor to determine the ratio of neuromuscular function. In a patient without NMB, the TOF ratio is greater than or equal to 1. If a patient is administered NMB agents, fade is observed from the first to fourth twitch, creating a TOF ratio less than 1. The degree of fade is proportional to the depth of patient neuromuscular blockade [3]. Subjective monitoring is known to be limited in its ability to accurately evaluate the level of NMB in patients, but is commonly used in clinical practice [4]. Despite strong evidence that objective monitoring prevents residual paralysis and resultant pulmonary complications, objective monitoring devices are not commonly used [5]. A strong contributing factor to this trend is design of monitoring devices. Devices fail to calculate consistent results because of calibration failure, inaccurate measurement due to tucked hand position, and failure due to patient repositioning during surgery. NMB monitors that consider clinical ergonomics would greatly improve patient outcomes. Challenges with developing an objective NMBmonitoring device, and the strengths and weaknesses of current technologies are provided.

Why Have So Many Intravascular Glucose Monitoring Devices Failed

Secondary to the inherent limitations of both point-of-care and central laboratory glucose technologies, continuous glucose measurement has recently enjoyed a high level of investment. Because of the perceived advantages by some of measuring in the intravascular space compared to the subcutaneous tissue, a number of technologies have been developed. In this review, we evaluate nine systems that have shown promise, although only one of these has been cleared for sale in the United States. The detection methodology, regulatory status, technical issues, and company circumstance surrounding each technology are examined.

Incidence of central venous catheter hub contamination

Purpose: To investigate microorganisms causing central venous catheter contamination and how this contamination differs across different catheter metrics. Materials and methods: After obtaining IRB approval and informed consent, 830 cultures were prospectively obtained from 45 ICU patients with central venous catheter or peripherally inserted central catheter. Bacterial colonies were identified by mass spectrometry. Results: Bacterial contamination of central catheter hubs occurred 44% of the time in this study in the ICU setting. Coagulase‐positive staphylococci cultures had higher median (± interquartile range) CFUs (12 ± 232) versus coagulase‐negative (3 ± 10) and other bacteria (1 ± 3; P < 0.001). Bacterial contamination was associated with various metrics. Higher incidence (P < 0.05) of coagulase‐positive staphylococci cultures was associated with hub‐only connections (a “hub” being a female connection; 10.9% vs. 7.9% male connections), connections without a manifold (1 lumen device that mixes multiple infusions together; 9.7% vs. 0% with manifold); and central venous pressure monitoring connections (25.8% vs. 7.1% without). Internal jugular sites (10.0% vs. 2.7% femoral, 6.2% PICC, P = 0.031) and medial lumens of triple lumen catheters (11.9% vs. 5.6% distal, 7.0% proximal, P = 0.049) had increased incidence of higher bacteria loads (> 15 CFUs). Conclusions: This study found a high incidence of central access catheter hub bacterial contamination, which correlated with positive blood cultures in 2 of 3 total bacteremia cases identified in the 45 patients. HighlightsCentral‐line associated blood stream infections increase length of hospital stay and costs of care.The needleless connectors (that is “hubs”) of the central line catheters in the intensive care unit had a high incidence (44%) of bacterial contamination.Further studies are needed to examine if bacterial contamination of the needless connectors may help identify patients at risk for central‐line associated blood stream infections.

A novel approach to improving efficiency and cost saving in preoperative blood preparation

Preoperative ordering of blood products has been an area of optimization due to considerable variability among physicians; overpreparation can lead to extra costs and underpreparation of blood can potentially compromise patient safety.