Ultrasonographic Inferior Vena Cava Measurement is More Sensitive Than Vital Sign Abnormalities for Identifying Moderate and Severe Hemorrhage.

BACKGROUND: Ultrasound inferior vena cava (IVC) diameter has been shown to decrease in response to hemorrhage. IVC diameter cut points to identify moderate and severe blood loss have not been established. OBJECTIVES: This study sought to find ultrasound IVC diameter cut points to identify moderate and severe hemorrhage and assess the performance of these cut points vs. vital sign abnormalities. METHODS: This is a secondary analysis of data from a study that described changes in vital signs and sonographic measurements of the IVC during a lower body negative pressure model of hemorrhage. Using receiver operator curve analyses, optimal cut points for identifying moderate and severe hemorrhage were identified. The ability of these cut points to identify hemorrhage in patients with no vital sign abnormalities was then assessed. RESULTS: In both long- and short-axis views, maximum and minimum IVC diameters (IVCmax and IVCmin) were significantly lower than baseline in severe blood loss. The optimal cut point for IVCmax in both axes was found to be ≤ 0.8 cm. This cut point is able to distinguish between no blood loss vs. moderate blood loss, and no blood loss vs. severe blood loss. The optimal cut point for IVCmin was variable between axes and blood loss severity. IVC diameter cut points obtained were able to identify hemorrhage in patients with no vital sign abnormalities. CONCLUSION: An ultrasound IVCmax of ≤ 0.8 cm may be useful in identifying moderate and severe hemorrhage before vital sign abnormalities are evident.

Inferior Vena Cava Diameter is an Early Marker of Central Hypovolemia during Simulated Blood Loss.

INTRODUCTION: Inferior vena cava (IVC) diameter decreases under conditions of hypovolemia. Point-of-care ultrasound (POCUS) may be useful to emergently assess IVC diameter. This study tested the hypothesis that ultrasound measurements of IVC diameter decreases during severe simulated blood loss. METHODS: Blood loss was simulated in 14 healthy men (22 ± 2 years) using lower body negative pressure (LBNP). Pressure within the LBNP chamber was reduced 10 mmHg of LBNP every four minutes until participants experienced pre-syncopal symptoms or until 80 mmHg of LBNP was completed. IVC diameter was imaged with POCUS using B-mode in the long and short axis views between minutes two and four of each stage. RESULTS: Maximum IVC diameter in the long axis view was lower than baseline (1.5 ± 0.4 cm) starting at -20 mmHg of LBNP (1.0 ± 0.3 cm; p < 0.01) and throughout LBNP (p < 0.01). The minimum IVC diameter in the long axis view was lower than baseline (0.9 ± 0.3 cm) at -20 mmHg of LBNP (0.5 ± 0.3 cm; p < 0.01) and throughout LBNP (p < 0.01). Maximum IVC diameter in the short axis view was lower than baseline (0.9 ± 0.2 cm) at 40 mmHg of LBNP (0.6 ± 0.2; p = 0.01) and the final LBNP stage (0.6 ± 0.2 cm; p < 0.01). IVC minimum diameter in the short axis view was lower than baseline (0.5 ± 0.2 cm) at the final LBNP stage (0.3 ± 0.2 cm; p = 0.01). CONCLUSION: These data demonstrate that IVC diameter decreases prior to changes in traditional vital signs during simulated blood loss. Further study is needed to determine the view and diameter threshold that most accurate for identifying hemorrhage requiring emergent intervention.

Overcoming barriers to promotion for women and underrepresented in medicine faculty in academic emergency medicine.

Equity in the promotion of women and underrepresented minorities (URiM) is essential for the advancement of academic emergency medicine and the specialty as a whole. Forward-thinking healthcare organizations can best position themselves to optimally care for an increasingly diverse patient population and mentor trainees by championing increased diversity in senior faculty ranks, leadership, and governance roles. This article explores several potential solutions to addressing inequities that hinder the advancement of women and URiM faculty. It is intended to complement the recently approved American College of Emergency Physicians (ACEP) policy statement aimed at overcoming barriers to promotion of women and URiM faculty in academic emergency medicine. This policy statement was jointly released and supported by the Society for Academic Emergency Medicine (SAEM), American Academy of Emergency Medicine (AAEM), and the Association of Academic Chairs of Emergency Medicine (AACEM).

Emergency Department Well-being Initiatives During the COVID-19 Pandemic: An After-action Review.

The COVID-19 pandemic has significantly impacted the well-being of our health care professionals, particularly frontline providers in the emergency department (ED). Our ED, located in New York City, was severely affected, exposing the staff to a combination of unique stressors. Our ED Wellness Committee responded by implementing various initiatives focusing on the physical, mental, and social needs of our providers to support them through this difficult time. The initiatives we describe offer a framework that may help other departments understand the importance of provider well-being during a pandemic.

Reliability and agreement of human renal and segmental artery hemodynamics measured using Doppler ultrasound.

To optimize study design and data interpretation, there is a need to understand the reliability of Doppler ultrasound-derived measures of blood velocity (BV) measured in the renal and segmental arteries. Thus, this study tested the following two hypotheses: 1) renal and segmental artery BV measured over the current standard of three cardiac cycles have good agreement with measurements over nine cardiac cycles (study 1); and 2) renal and segmental artery BV measurements have relatively poor day-to-day reliability (study 2). In study 1, there was excellent agreement between measurements over three and nine cardiac cycles for BV in both the renal and segmental arteries, as evidenced by BV measurements that were not statistically different (P ≥ 0.68), were highly consistent (r ≥ 0.99, P < 0.01), had a coefficient of variation ≤2.5 ± 1.8%, and 97% (renal artery) and 92% (segmental artery) of the individual differences fell within the 95% limits of agreement. In study 2, there was relatively good day-to-day reliability in renal artery BV as evidenced by no differences between three separate days (P ≥ 0.30), an intraclass correlation coefficient (ICC) of 0.92 (0.78, 0.98), and 7.4 ± 5.5% coefficient of variation. The day-to-day reliability was relatively poor in the segmental artery with an ICC of 0.77 (0.41, 0.93) and 9.0 ± 5.6% coefficient of variation. These findings support measuring renal and segmental artery hemodynamics over three cardiac cycles and the utility in reporting renal BV across days. However, because of the variation across days, hemodynamic responses in the segmental arteries should be reported as changes from baseline when making comparisons across multiple days.NEW & NOTEWORTHY The present study indicates that Doppler ultrasound-derived measures of renal and segmental artery hemodynamics over three cardiac cycles have excellent agreement with those over nine cardiac cycles. These findings support the current practice of measuring renal and segmental artery blood velocity over three cardiac cycles. This study also demonstrates that there is excellent day-to-day reliability for measures of renal artery blood velocity, which supports reporting absolute values of renal artery blood velocity across days. However, it was also found that the day-to-day reliability of segmental artery measurements is relatively poor. Thus, to account for this variability, we suggest that segmental artery hemodynamics be compared as relative changes from baseline across separate days.

Renal and segmental artery hemodynamics during whole body passive heating and cooling recovery.

High environmental temperatures are associated with increased risk of acute kidney injury, which may be related to reductions in renal blood flow. The susceptibility of the kidneys may be increased because of heat stress-induced changes in renal vascular resistance (RVR) to sympathetic activation. We tested the hypotheses that, compared with normothermia, increases in RVR during the cold pressor test (CPT, a sympathoexcitatory maneuver) are attenuated during passive heating and exacerbated after cooling recovery. Twenty-four healthy adults (22 ± 2 yr; 12 women, 12 men) completed CPTs at normothermic baseline, after passive heating to a rise in core temperature of ~1.2°C, and after cooling recovery when core temperature returned to ~0.2°C above normothermic baseline. Blood velocity was measured by Doppler ultrasound in the distal segment of the right renal artery (Renal, n = 24 during thermal stress, n = 12 during CPTs) or the middle portion of a segmental artery (Segmental, n = 12). RVR was calculated as mean arterial pressure divided by renal or segmental blood velocity. RVR increased at the end of CPT during normothermic baseline in both arteries (Renal: by 1.0 ± 1.0 mmHg·cm-1·s, Segmental: by 2.2 ± 1.2 mmHg·cm-1·s, P ≤ 0.03), and these increases were abolished with passive heating (P ≥ 0.76). At the end of cooling recovery, RVR in both arteries to the CPT was restored to that of normothermic baseline (P ≤ 0.17). These data show that increases in RVR to sympathetic activation during passive heating are attenuated and return to that of normothermic baseline after cooling recovery.NEW & NOTEWORTHY Our data indicate that increases in renal vascular resistance to the cold pressor test (i.e., sympathetic activation) are attenuated during passive heating, but at the end of cooling recovery this response returns to that of normothermic baseline. Importantly, hemodynamic responses were assessed in arteries going to (renal artery) and within (segmental artery) the kidney, which has not been previously examined in the same study during thermal and/or sympathetic stressors.

Avoid the Goose! Paramedic Identification of Esophageal Intubation by Ultrasound.

OBJECTIVES: Rapid identification of esophageal intubations is critical to avoid patient morbidity and mortality. Continuous waveform capnography remains the gold standard for endotracheal tube (ETT) confirmation, but it has limitations. Point-of-care ultrasound (POCUS) may be a useful alternative for confirming ETT placement. The objective of this study was to determine the accuracy of paramedic-performed POCUS identification of esophageal intubations with and without ETT manipulation. METHODS: A prospective, observational study using a cadaver model was conducted. Local paramedics were recruited as subjects and each completed a survey of their demographics, employment history, intubation experience, and prior POCUS training. Subjects participated in a didactic session in which they learned POCUS identification of ETT location. During each study session, investigators randomly placed an ETT in either the trachea or esophagus of four cadavers, confirmed with direct laryngoscopy. Subjects then attempted to determine position using POCUS both without and with manipulation of the ETT. Manipulation of the tube was performed by twisting the tube. Descriptive statistics and logistic regression were used to assess the results and the effects of previous paramedic experience. RESULTS: During 12 study sessions, from March 2014 through December 2015, 57 subjects participated, evaluating a total of 228 intubations: 113 tracheal and 115 esophageal. Subjects were 84.0% male, mean age of 39 years (range: 22 - 62 years), with median experience of seven years (range: 0.6 - 39 years). Paramedics correctly identified ETT location in 158 (69.3%) cases without and 194 (85.1%) with ETT manipulation. The sensitivity and specificity of identifying esophageal location without ETT manipulation increased from 52.2% (95% confidence interval [CI], 43.0-61.0) and 86.7% (95% CI, 81.0-93.0) to 87.0% (95% CI, 81.0-93.0) and 83.2% (95% CI, 0.76-0.90) after manipulation (P<.0001), without affecting specificity (P=.45). Subjects correctly identified 41 previously incorrectly identified esophageal intubations. Paramedic experience, previous intubations, and POCUS experience did not correlate with ability to identify tube location. CONCLUSION: Paramedics can accurately identify esophageal intubations with POCUS, and manipulation improves identification. Further studies of paramedic use of dynamic POCUS to identify inadvertent esophageal intubations are needed. LemaPC, O'BrienM, WilsonJ, St. JamesE, LindstromH, DeAngelisJ, CaldwellJ, MayP, ClemencyB. Avoid the goose! Paramedic identification of esophageal intubation by ultrasound. Prehosp Disaster Med. 2018;33(4):406-410.

Diagnosis of Hand Infections in Intravenous Drug Users by Ultrasound and Water Bath: A Case Series.

We present three cases of hand injury by intravenous drug users in which point-of-care ultrasound, using a specific water bath technique, was able to quickly and efficiently delineate severity of injury. This technique benefited these patients by allowing a painless assessment of their injury for soft tissue injury vs. abscess formation and allowed providers to determine at the bedside whether these patients required immediate surgical intervention.

Asteroid Hyalosis Masquerading as Vitreous Hemorrhage on Point-of-Care Sonography.

Point-of-care ocular sonography is frequently used in the emergency department to evaluate patients with vision disorders. We describe a case series of 3 patients who ultimately had a diagnosis of asteroid hyalosis, a lesser-known condition that on point-of-care sonography may be mistaken for vitreous hemorrhage. Asteroid hyalosis is considered a benign degenerative condition. In contrast, vitreous hemorrhage may be an ocular emergency that warrants an urgent ophthalmologic consultation if there is an underlying retinal tear or detachment. Although similar in appearance on sonography, recognition of the subtle pathognomonic sonographic features along with their clinical presentations can differentiate these diseases, with vastly different management strategies and dispositions.

Renal Hemodynamics During Sympathetic Activation Following Aerobic and Anaerobic Exercise.

We tested the hypotheses that prior aerobic (Study 1) or anaerobic (Study 2) exercise attenuates the increase in renal vascular resistance (RVR) during sympathetic stimulation. Ten healthy young adults (5 females) participated in both Study 1 (aerobic exercise) and Study 2 (anaerobic exercise). In Study 1, subjects completed three minutes of face cooling pre- and post- 30 min of moderate intensity aerobic exercise (68 ± 1% estimate maximal heart rate). In Study 2, subjects completed two minutes of the cold pressor test pre- and post- the completion of a 30 s maximal effort cycling test (Wingate Anaerobic Test). Both face cooling and the cold pressor test stimulate the sympathetic nervous system and elevate RVR. The primary dependent variable in both Studies was renal blood velocity, which was measured at baseline and every minute during sympathetic stimulation. Renal blood velocity was measured via the coronal approach at the distal segment of the right renal artery with pulsed wave Doppler ultrasound. RVR was calculated from the quotient of mean arterial pressure and renal blood velocity. In Study 1, renal blood velocity and RVR did not differ between pre- and post- aerobic exercise (P ≥ 0.24). Face cooling decreased renal blood velocity (P < 0.01) and the magnitude of this decrease did not differ between pre- and post- aerobic exercise (P = 0.52). RVR increased with face cooling (P < 0.01) and the extent of these increases did not differ between pre- and post- aerobic exercise (P = 0.74). In Study 2, renal blood velocity was 2 ± 2 cm/s lower post- anaerobic exercise (P = 0.02), but RVR did not differ (P = 0.08). The cold pressor test decreased renal blood velocity (P < 0.01) and the magnitude of this decrease did not differ between pre- and post- anaerobic exercise (P = 0.26). RVR increased with the cold pressor test (P < 0.01) and the extent of these increases did not differ between pre- and post- anaerobic exercise (P = 0.12). These data indicate that 30 min of moderate intensity aerobic exercise or 30 s of maximal effort anaerobic exercise does not affect the capacity to increase RVR during sympathetic stimulation following exercise.