Medical procedures that produce aerosolized particles are under great scrutiny due to the recent concerns surrounding the COVID-19 virus and increased risk for nosocomial infections. For example, ...thoracostomies, tracheotomies and intubations/extubations produce aerosols that can linger in the air. The lingering time is dependent on particle size where, e.g., 500 μm (0.5 mm) particles may quickly fall to the floor, while 1 μm particles may float for extended lengths of time. Here, a method is presented to characterize the size of <40 μm to >600 μm particles resulting from surgery in an operating room (OR). The particles are measured in-situ (next to a patient on an operating table) through a 75mm aperture in a ∼400 mm rectangular enclosure with minimal flow restriction. The particles and gasses exiting a patient are vented through an enclosed laser sheet while a camera captures images of the side-scattered light from the entrained particles. A similar optical configuration was described by Anfinrud et al.; however, we present here an extended method which provides a calibration method for determining particle size. The use of a laser sheet with side-scattered light provides a large FOV and bright image of the particles; however, the particle image dilation caused by scattering does not allow direct measurement of particle size. The calibration routine presented here is accomplished by measuring fixed particle distribution ranges with a calibrated shadow imaging system and mapping these measurements to the in-situ imaging system. The technique used for generating and measuring these particles is described. The result is a three-part process where 1) particles of varying sizes are produced and measured using a calibrated, high-resolution shadow imaging method, 2) the same particle generators are measured with the in-situ imaging system, and 3) a correlation mapping is made between the (dilated) laser image size and the measured particle size. Additionally, experimental and operational details of the imaging system are described such as requirements for the enclosure volume, light management, air filtration and control of various laser reflections. Details related to the OR environment and requirements for achieving close proximity to a patient are discussed as well.
Alcohol withdrawal syndrome (AWS) represents significant cost to the hospitalized trauma population from a clinical and financial perspective. Historically, AWS has been managed with benzodiazepines. ...Despite their efficacy, benzodiazepines carry a heavy adverse effect profile. Recently, benzodiazepine-sparing protocols for the prophylaxis and treatment of AWS have been used in medical patient populations. Most existing benzodiazepine-sparing protocols use phenobarbital, while ours primarily uses gabapentin and clonidine, and no such protocol has been developed and examined for safety and efficacy specifically within a trauma population.
In December of 2019, we implemented our benzodiazepine-sparing protocol for trauma patients identified at risk for alcohol withdrawal on admission. Trauma patients at risk for AWS admitted to an academic Level 1 trauma center before (conventional) and after (benzodiazepine-sparing BS) protocol implementation were compared. Outcomes examined include morphine milligram equivalent dosing rates and lorazepam equivalent dosing rates as well as the Clinical Institute Withdrawal Assessment for Alcohol, revised (CIWA-Ar) scores, hospital length of stay, intensive care unit length of stay, and ventilator days.
A total of 387 conventional and 134 benzodiazepine sparing patients were compared. Injury Severity Score (13 vs. 16, p = 0.10) and admission alcohol levels (99 vs. 149, p = 0.06) were similar. Patients in the BS pathway had a lower maximum daily CIWA-Ar (2.7 vs. 1.5, p = 0.04). While mean morphine milligram equivalent per day was not different between groups (31.5 vs. 33.6, p = 0.49), mean lorazepam equivalents per day was significantly lower in the BS group (1.1 vs. 0.2, p < 0.01). Length of stay and vent days were not different between the groups.
Implementation of a benzodiazepine-sparing pathway that uses primarily clonidine and gabapentin to prevent and treat alcohol withdrawal syndrome in trauma patients is safe, reduces the daily maximum CIWA-Ar, and significantly decreases the need for benzodiazepines. Future studies will focus on outcomes affected by avoiding AWS and benzodiazepines in the trauma population.
Therapeutic/Care Management; Level IV.
Older patients are expected to comprise 40 % of trauma admissions in the next 30 years. The use of whole blood (WB) has shown promise in improving mortality while lowering the utilization of blood ...products. However, the use of WB in older trauma patients has not been examined. The objective of our study is to determine the safety and efficacy of a WB first transfusion strategy in injured older patients.
Older trauma patients, defined as age ≥55 years old, were reviewed from March 2016-November 2021. Patients that received a WB first resuscitation strategy were compared to those that received a ratio based component strategy. Demographics as well as complications rates, blood product transfusion volumes, and mortality were evaluated. Univariate and multivariable analysis was used to determine independent predictors of mortality.
There were 388 older trauma patients that received any blood products during the study period. A majority of patients received a WB first resuscitation strategy (83 %). Compared to patients that received component therapy, patients that received WB first were more likely female, less likely to have a penetrating mechanism, and had a slightly lower injury severity score. The-30 day mortality rate was comparable (WB 36% vs component 37 %, p = 0.914). While rates of AKI were slightly higher in those that received WB, this did not result in increased rates of renal replacement therapy (3 % vs 2 %, p = 1). Further, compared to patients that received components, patients that were resuscitated with a WB first strategy significantly utilized lower median volumes of platelets (0 mL vs 197 mL, p < 0.001), median volumes of plasma (0 mL vs 1253 mL, p < 0.001, and median total volume of blood products (1000 mL vs 2859 mL, p < 0.001).
The use of WB in the older trauma patient appears safe, with mortality and complication rates comparable to component therapy. Blood product utilization is significantly less in those that are resuscitated with WB first.
AMP-activated protein kinase (AMPK) is an energy-sensing serine/threonine protein kinase that plays a central role in whole-body energy homeostasis. AMPK is a heterotrimeric enzyme with a catalytic ...(α) subunit and two regulatory (β and γ) subunits. The muscle-specific AMPK heterotrimeric complex (α2β2γ3) is involved in glucose and fat metabolism in skeletal muscle and therefore has emerged as an attractive target for drug development for diabetes and metabolic syndrome. To date, expression of recombinant full-length human AMPK α2β2γ3 has not been reported. Here we describe the expression, purification and biochemical characterization of functional full-length AMPK α2β2γ3 heterotrimeric complex using an
Escherichia coli expression system. All three subunits of AMPK α2β2γ3 were transcribed as a single tricistronic transcript driven by the T7 RNA polymerase promoter, allowing spontaneous formation of the heterotrimeric complex in the bacterial cytosol. The self-assembled trimeric complex was purified from the cell lysate by nickel-ion chromatography using the hexahistidine tag fused exclusively at the N-terminus of the α 2 domain. The un-assembled β 2 and γ 3 domains were removed by extensive washing of the column. Further purification of the heterotrimer was performed using size exclusion chromatography. The final yield of the recombinant AMPK α2β2γ3 complex was 1.1
mg/L culture in shaker flasks. The
E. coli expressed enzyme was catalytically inactive after purification, but was activated
in vitro by upstream kinases such as CaMKKβ and LKB1. The kinase activity of activated AMPK α2β2γ3 complex was significantly enhanced by AMP (an allosteric activator) but not by thienopyridone A-769662, a known small molecule activator of AMPK. Mass spectrometric characterization of recombinant AMPK α2β2γ3 showed significant heterogeneity before and after activation that could potentially hamper crystallographic studies of this complex.
AMP-activated protein kinase (AMPK) is an energy-sensing serine/threonine protein kinase that plays a central role in whole-body energy homeostasis. AMPK is a heterotrimeric enzyme with a catalytic ...(a) subunit and two regulatory (b and g) subunits. The muscle-specific AMPK heterotrimeric complex (a2b2g3) is involved in glucose and fat metabolism in skeletal muscle and therefore has emerged as an attractive target for drug development for diabetes and metabolic syndrome. To date, expression of recombinant full-length human AMPK a2b2g3 has not been reported. Here we describe the expression, purification and biochemical characterization of functional full-length AMPK a2b2g3 heterotrimeric complex using an Escherichia coli expression system. All three subunits of AMPK a2b2g3 were transcribed as a single tricistronic transcript driven by the T7 RNA polymerase promoter, allowing spontaneous formation of the heterotrimeric complex in the bacterial cytosol. The self-assembled trimeric complex was purified from the cell lysate by nickel-ion chromatography using the hexahistidine tag fused exclusively at the N-terminus of the a 2 domain. The un-assembled b 2 and g 3 domains were removed by extensive washing of the column. Further purification of the heterotrimer was performed using size exclusion chromatography. The final yield of the recombinant AMPK a2b2g3 complex was 1.1 mg/L culture in shaker flasks. The E. coli expressed enzyme was catalytically inactive after purification, but was activated in vitro by upstream kinases such as CaMKKb and LKB1. The kinase activity of activated AMPK a2b2g3 complex was significantly enhanced by AMP (an allosteric activator) but not by thienopyridone A-769662, a known small molecule activator of AMPK. Mass spectrometric characterization of recombinant AMPK a2b2g3 showed significant heterogeneity before and after activation that could potentially hamper crystallographic studies of this complex.
Background Nonoperative management (NOM) of blunt splenic injury is well accepted. Substantial failure rates in higher injury grades remain common, with one large study reporting rates of 19.6%, ...33.3%, and 75% for grades III, IV, and V, respectively. Retrospective data show angiography and embolization can increase salvage rates in these severe injuries. We developed a protocol requiring referral of all blunt splenic injuries, grades III to V, without indication for immediate operation for angiography and embolization. We hypothesized that angiography and embolization of high-grade blunt splenic injury would reduce NOM failure rates in this population. Study Design This was a prospective study at our Level I trauma center as part of a performance-improvement project. Demographics, injury characteristics, and outcomes were compared with historic controls. The protocol required all stable patients with grade III to V splenic injuries be referred for angiography and embolization. In historic controls, referral was based on surgeon preference. Results From January 1, 2010 to December 31, 2012, there were 168 patients with grades III to V spleen injuries admitted; NOM was undertaken in 113 (67%) patients. The protocol was followed in 97 patients, with a failure rate of 5%. Failure rate in the 16 protocol deviations was 25% (p = 0.02). Historic controls from January 1, 2007 to December 31, 2009 were compared with the protocol group. One hundred and fifty-three patients with grade III to V injuries were admitted during this period, 80 (52%) patients underwent attempted NOM. Failure rate was significantly higher than for the protocol group (15%, p = 0.04). Conclusions Use of a protocol requiring angiography and embolization for all high-grade spleen injuries slated for NOM leads to a significantly decreased failure rate. We recommend angiography and embolization as an adjunct to NOM for all grade III to V splenic injuries.
Background
COPD diagnosis is tightly linked to the fixed-ratio spirometry criteria of FEV
1
/FVC < 0.7. African-Americans are less often diagnosed with COPD.
Objective
Compare COPD diagnosis by ...fixed-ratio with findings and outcomes by race.
Design
Genetic Epidemiology of COPD (COPDGene) (2007–present), cross-sectional comparing non-Hispanic white (NHW) and African-American (AA) participants for COPD diagnosis, manifestations, and outcomes.
Setting
Multicenter, longitudinal US cohort study.
Participants
Current or former smokers with ≥ 10-pack-year smoking history enrolled at 21 clinical centers including over-sampling of participants with known COPD and AA. Exclusions were pre-existing non-COPD lung disease, except for a history of asthma.
Measurements
Subject diagnosis by conventional criteria. Mortality, imaging, respiratory symptoms, function, and socioeconomic characteristics, including area deprivation index (ADI). Matched analysis (age, sex, and smoking status) of AA vs. NHW within participants
without
diagnosed COPD (GOLD 0; FEV
1
≥ 80% predicted and FEV
1
/FVC ≥ 0.7).
Results
Using the fixed ratio, 70% of AA (
n
= 3366) were classified as non-COPD, versus 49% of NHW (
n
= 6766). AA smokers were younger (55 vs. 62 years), more often current smoking (80% vs. 39%), with fewer pack-years but similar 12-year mortality. Density distribution plots for FEV
1
and FVC raw spirometry values showed disproportionate reductions in FVC relative to FEV
1
in AA that systematically led to higher ratios. The matched analysis demonstrated GOLD 0 AA had greater symptoms, worse D
L
CO, spirometry, BODE scores (1.03 vs 0.54,
p
< 0.0001), and greater deprivation than NHW.
Limitations
Lack of an alternative diagnostic metric for comparison.
Conclusions
The fixed-ratio spirometric criteria for COPD underdiagnosed potential COPD in AA participants when compared to broader diagnostic criteria. Disproportionate reductions in FVC relative to FEV
1
leading to higher FEV
1
/FVC were identified in these participants and associated with deprivation. Broader diagnostic criteria for COPD are needed to identify the disease across all populations.
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