Augmentation of peripheral venous diameter for ultrasound-guided peripheral intravenous line insertion.

OBJECTIVES: Ultrasound-guided intravenous line placement is utilized often in the emergency department for venous access in patients whose veins are difficult to cannulate by traditional methods. This study aims to identify specific interventions that will augment venous cross-sectional area. METHODS: Residents and medical students volunteers each had their basilic vein identified using the linear array probe on an ultrasound. The area of the vein was measured with no intervention with the arm positioned parallel to the floor as well as approximately 45 degrees below the level of the bed. These two positions were repeated with the following interventions: one standard rubber tourniquet applied proximal to the vein measurement, an additional rubber tourniquet applied proximal to first tourniquet, blood pressure cuff inflated to between 160 and 200 mmHg applied proximal to the vein, CAT battle tourniquet application proximal to measurement site, and soaked warm towel applied to brachium for up to one minute. The primary outcome was to evaluate the increase in venous cross-sectional area from the baseline measurement after the interventions. RESULTS: We had 41 participants in this study. All interventions were statistically significant in increasing venous cross-sectional area as compared to no intervention, with the most significant augmentation being from the CAT battle tourniquet (mean change +7.32 mm2, 95% CI, 5.73-8.91 mm2) . The change in position of the arm, was not statistically significant for any intervention except for the CAT tourniquet (mean change -1.74 mm2, 95% CI, -0.54 to -2.93 mm2). There was no significant difference between two tourniquets and blood pressure cuff (mean change +0.58 mm2, 95% CI, -1.13 to +2.29 mm2), but there was a significant increase in cross-sectional area with CAT tourniquet use compared to blood pressure cuff (mean change +1.62 mm2, 95% CI, 0.29-2.95 mm2). Lastly, two tourniquets increased cross- sectional area compared to one tourniquet (mean change +2.20 mm2, 95% CI, 1.14 - +3.26 mm2). CONCLUSIONS: This study identified several potential interventions for maximizing venous cross-sectional area on ultrasound. All the tested interventions resulted in statistically significant increases in cross-sectional area. Arm positioning did not show significant changes in most interventions, with the exception of the CAT tourniquet. Further studies should be performed on how these maneuvers affect success in ultrasound-guided intravenous line placement.

Failure Rates During Reuse of Disposable N95 Masks in Clinical Practice in the Emergency Department.

INTRODUCTION: The coronavirus 2019 pandemic caused a shortage of disposable N95 respirators, prompting healthcare entities to extend the use of these masks beyond their intended single-use manufacturer recommendation with a paucity of supporting research. METHODS: We performed a prospective cohort study of ED healthcare workers (HCW) ("subjects") required to use respirators at an academic, Level I trauma center. Subjects had been previously fit tested and assigned an appropriately sized N95 mask per hospital protocol. Per study protocol, subjects were fit tested periodically throughout their shifts and on multiple shifts over the eight-week study period. Data points collected included the age of the mask, subjective assessment of mask seal quality, and fit test results. We analyzed the data using Fisher's exact test, and calculated odds ratios (OR) to determine the failure rate of disposable N95 masks following reuse. RESULTS: A total of 130 HCWs underwent fit testing and 127 were included for analysis. Mask failure rate climbed after day 2 of use, with 33.3% of masks failing at day 3, 42.9% at day 4, and 50% at ≥ day 5. Categorizing the masks into those being used for two or fewer days vs those in use for three or more, failure was more common on day 3 of use or older compared to those in the first two days of use (41.8% vs 8.3%, P < 0.0001) with an OR of failure with an older mask of 7.9 (confidence interval [CI], 2.8-22.3). The healthcare workers' assessment of poor seal was 33.3% sensitive (CI, 18.6-51.9) and 95.7% specific (CI, 88.8-98.6) for fit test failure. CONCLUSION: Disposable N95 masks have significant failure rates following reuse in clinical practice. Healthcare personnel also performed poorly in assessing the integrity of the seal of their disposable respirators.

The pragmatic use of industrial elastomeric facemasks in health care practice during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has forced health care workers to explore alternative personal protective equipment (PPE) strategies due to traditional product shortages in the setting of increased global demand. Some physicians have chosen to use elastomeric face masks (EFMs), traditionally used in non-healthcare industries. METHODS: We performed a prospective cohort study of Emergency Medicine (EM) physicians working at a Level 1 Trauma Center who chose to use self-supplied EFMs for PPE. All subjects used commercial EFMs with disposable filters (N95, P95, or P100). All subjects chose their mask size independently with no input from employee health regarding appropriate fit. Per study protocol, subjects were fit tested periodically during clinical shifts over the course of the 6-week study period. All investigators performing fit testing underwent OSHA qualitative fit testing training. Data collected included mask/filters age, subjective assessment of mask seal quality, and fit test results. The data were analyzed using descriptive statistics. RESULTS: 105 fit tests were performed on physicians wearing EFMs over the course of 49 shifts. Physicians felt their fit was adequate for all tests performed. There were no fit test failures in any subjects. CONCLUSIONS: EFMs have an extremely low failure rate. Physicians are able to assess the adequacy of fit and accurately choose EFM size.

The efficacy of continuous use disposable N95 masks in clinical practice in the emergency department.

During the SARS-CoV-2 pandemic, many emergency departments (EDs) initiated continuous use of N95 disposable respirators (N95s) rather than discarding them after each use to conserve respirators. This study investigates the efficacy of wearing disposable N95s continuously during clinical work. METHODS: This is a prospective cohort study of ED staff required to wear N95s continuously throughout their shifts. Subjects were doctors, nurses, and technicians who were previously fitted for their assigned N95 by employee health. Subjects were fit tested periodically throughout their shifts. Investigators filled out a questionnaire for each subject noting the hours of continuous N95 wear. Data were analyzed using descriptive statistics. RESULTS: One hundred thirteen N95s were evaluated, with 23 failures at first testing. These were not retested. Twenty-seven N95s passed at the start of a shift and did not have repeat testing during the course of the shift. These were excluded from further analysis. Seventeen N95s passed testing after several hours of continuous wear, but only had a single fit test done partway or at the end of a shift. These were assumed to have passed if tested at shift start, and were assigned as "passes" for continuous use. Forty-six N95s had an initial pass and were evaluated for continuous use, of which 6 subsequently failed later in the shift, giving a fail rate with continuous use of 9.5%. CONCLUSION: Continuous use of disposable N95s throughout an ED shift is reasonable during a PPE shortage if wearers are assured of fit at the start of their shift.

Impact of Phlebotomy Tourniquet Use on Blood Lactate Levels in Acutely Ill Patients.

OBJECTIVE: Lactate levels are increasingly used to guide resuscitation efforts. Some surgical literature suggests that tourniquet use during phlebotomy falsely elevates results, although studies in healthy volunteers have not demonstrated this. The purpose of this study was to determine in clinical practice whether tourniquet use during the drawing of a lactate results in significantly altered levels compared to the result of a level drawn without a tourniquet. METHODS: A prospective cohort study was carried out on emergency department patients whose clinical presentation led a physician to order a lactate level. Written informed consent was obtained from patients or their proxies. Study lactates were obtained using a tourniquet during the draw sequence of other laboratory studies. Lactate levels for clinical use were drawn per hospital protocol with no tourniquet. The time of lactate measurements and patient demographic information were recorded. Lactate levels for each patient were compared with the Wilcoxon Rank-Sum Test. RESULTS: 40 patients were consented and enrolled. The median clinical lactate level was 1.9 (interquartile range 1.5-2.6), and the median study lactate level was 1.9 (interquartile range 1.4-2.7). There was no difference between paired lactate values (p=0.95). CONCLUSIONS: Tourniquet use appears to have no impact on measured lactate levels. Our findings suggest that current practices at many institutions regarding lactate collection are likely too stringent and should be changed.

Misidentification of English Language Proficiency in Triage: Impact on Satisfaction and Door-to-Room Time.

We examined triage nurses' assessment of patients' language proficiency compared to patients' self-reported proficiency and the impact of language discordance on door-to-room time and patient satisfaction. This was a prospective study of emergency department walk-in patients. Patients completed a survey in which they identified their language proficiency. On a Likert scale, patients ranked how well they felt they were understood and how satisfied they were with the triage process. Nurses completed surveys identifying the patient's primary language and how well they felt they understood the patient. Door-to-room times were obtained from medical records. 163 patients were enrolled. 66% of patients identified themselves as having good English proficiency, while 34% of patients had limited English proficiency. Nurses misclassified 27% of self-identified Spanish-speaking patients as being English proficient. Spanish-speakers felt less satisfied with triage than English-speakers (p < 0.01). There were no differences in door-to-room time. Triage nurses overestimate patient language skills. Spanish-speaking patients feel less satisfied with triage than English-speakers.

Molecular basis of the dual functions of 2B4 (CD244).

2B4 belongs to the CD2 family of molecules and is expressed on all NK, gammadelta, and memory CD8(+) (alphabeta) T cells. The murine NK receptor 2B4 exhibits both inhibitory and activating functions, whereas human 2B4 has been reported to be an activating molecule. How murine 2B4 can act both as an activating and inhibitory receptor and what distinguishes its function from human 2B4 have remained largely unknown. We use here a model system that allows the study of human and murine 2B4 under identical and controlled conditions. These studies reveal that both human and mouse 2B4 can activate or inhibit NK cells. We show here that the level of 2B4 expression and the degree of 2B4 cross-linking play a significant role in the regulation of signaling lymphocyte activation molecule-associated protein-mediated activation by 2B4. A high level of 2B4 expression, heavy cross-linking, and relative paucity of signaling lymphocyte activation molecule-associated protein promote inhibitory function. Our studies demonstrate how a single receptor can have opposing function depending on the degree of receptor expression, extent of its ligation, and the relative abundance of certain adaptor molecules. Because the levels of 2B4 and CD48 are dynamically regulated, these findings have implications for the regulation of NK cell function.