Recent studies have illustrated that mesenchymal stem cells possess the potential to differentiate along an endothelial lineage, but the effect of shear on mesenchymal differentiation is unknown. ...Thus, we developed an in vitro shear stress system to examine the relationship between shear stress and the endothelial differentiation of a murine embryonic mesenchymal progenitor cell line, C3H/10T1/2.
The parallel plate system of fluid shear stress was used. Shear stress significantly induced expression of mature endothelial cell-specific markers in CH3H/10T1/2 cells such as CD31, von Willebrand factor, and vascular endothelial-cadherin at both the mRNA and protein levels with real-time polymerase chain reaction and immunofluorescence analyses, respectively. In addition, shear-induced augmentation of functional markers of the mature endothelial phenotype such as uptake of acetylated low-density lipoproteins and formation of capillary-like structures on Matrigel. Furthermore, shear stress significantly upregulated angiogenic growth factors while downregulating growth factors associated with smooth muscle cell differentiation.
This study demonstrates, for the fist time, endothelial differentiation in a mesenchymal progenitor CH3H/10T1/2 cell line resulting from shear exposure. Thus, this analysis may serve as a basis for further understanding the effect of shear on mesenchymal and vascular cell differentiation.
Enoxaparin sodium is widely used for deep vein thrombosis (DVT) prophylaxis, yet DVT rates remain high in the trauma and general surgery populations. Missed doses during hospitalization are common.
...To determine if missed doses of enoxaparin correlate with DVT formation.
Data were prospectively collected among 202 trauma and general surgery patients admitted to a level I trauma center.
Deep vein thrombosis screening was performed using a rigorous standardized protocol.
The overall incidence of DVT was 15.8%. In total, 58.9% of patients missed at least 1 dose of enoxaparin. The DVTs occurred in 23.5% of patients who missed at least 1 dose and in 4.8% of patients who did not (P < .01). On univariate analysis, the need for mechanical ventilation (71.8% vs 44.1%), the performance of more than 1 operation (59.3% vs 40.0%), and male sex (75% vs 56%) were associated with DVT formation (P < .05 for all). A bivariate logistic regression was then performed, which revealed age 50 years or older and interrupted enoxaparin therapy as the only independent risk factors for DVT formation. The DVT rate did not differ between trauma and general surgery populations or in patients receiving once-daily vs twice-daily dosing regimens.
Interrupted enoxaparin therapy and age 50 years or older are associated with DVT formation among trauma and general surgery patients. Missed doses occur commonly and are the only identified risk factor for DVT that can be ameliorated by physicians. Efforts to minimize interrupted enoxaparin prophylaxis in patients at risk for DVT should be optimized.
Abstract Background The purpose of this study was to compare standard gauze (SG) and advanced hemostatic dressings in use by military personnel in a no-hold model. Methods A randomized, controlled ...trial was conducted using 36 swine. Animals underwent femoral arteriotomy, followed by 60 seconds of uncontrolled hemorrhage. After hemorrhage, packing with 1 of 3 dressings—SG, Combat Gauze (CG), or Celox Rapid gauze (XG)—and a 500-mL bolus of Hextend were initiated. Pressure was not held after packing, and animals were followed for 120 minutes. Physiologic parameters were monitored continuously, and electrolyte and hematologic laboratory assessments were performed before injury and 30 and 120 minutes after injury. Dressing failure was determined if bleeding occurred outside the wound. Results All animals survived to study end. Baseline characteristics were similar between groups. No statistical difference was seen in initial blood loss or dressing success rate (SG, 10 of 12; CG, 10 of 12; and XG, 12 of 12). Secondary blood loss was significantly less with XG (median, 12.8 mL; interquartile range, 8.8 to 39.7 mL) compared with SG (median, 44.7 mL; interquartile range, 17.8 to 85.3 mL; P = .02) and CG (median, 31.9 mL; interquartile range, 18.6 to 69.1 mL; P = .05). Packing time was significantly shorter with XG (mean, 37.1 ± 6.2 seconds) compared with SG (mean, 45.2 ± 6.0 seconds; P < .01) and CG (mean, 43.5 ± 5.6 seconds; P = .01). Conclusions XG demonstrated shorter application time and decreased secondary blood loss in comparison with both SG and CG. These differences may be of potential benefit in a care-under-fire scenario.
The state of Montana encompasses and defines rural health care as it is known in the United States (US) today. This vast area is punctuated by pockets of health care availability with varying access ...to blood products for transfusion. Furthermore, timely transport is frequently challenged by weather that may limit air transportation options, resulting in multiple hours in ground transport to definitive care.
The Montana State Trauma Care Committee (MT-STCC) developed the Montana Interfacility Blood Network (MT-IBN) to ensure blood availability in geographically distanced cases where patients may otherwise not survive. The index case that led to the formal development of the MT-IBN is described, followed by a second case illustrating the IBN process.
This process and development manuscript details the innovative efforts of MT-STCC to develop this fledgling idea unique to rural US health care. We review guidelines that have been developed to define broad aspects of the MT-IBN including the reason to share resources, proper packaging, paperwork necessary for transfer, and how to provide resources directly to the patient. Finally, we describe implementation within the state.
The MT-IBN was developed by MT-STCC to facilitate the hand-off of lifesaving blood to patients being transported by ground to definitive care in Montana without having to stop at an intermediary facility. This has already led to lives saved in areas that are limited in blood availability due to rurality.
Abstract Background The International Normalized Ratio (INR) is commonly used to guide therapy after hepatectomy. We hypothesized that the use of thrombelastography (TEG) would demonstrate a ...decreased incidence of hypocoagulability in this patient population. Methods Seventy-eight patients were prospectively enrolled before undergoing hepatectomy. INR, TEG, and coagulation factors were drawn before incision, postoperatively, and on postoperative days 1, 3, and 5. Results Patients demonstrated an elevated INR at all postoperative time points. However, TEG demonstrated a decreased R value postoperatively, with subsequent normalization. Other TEG measurements were equivalent to preoperative values. All procoagulant factors save factor VIII decreased postoperatively, with a simultaneous decrease in protein C. Conclusions TEG demonstrated a brief hypercoagulable state after major hepatectomy, with coagulation subsequently normalizing. The INR significantly overestimates hypocoagulability after hepatectomy and these data call into question current practices using the INR to guide therapy in this patient population.
Time to definitive surgical debridement has been recognized as a predictor for morbidity and mortality in necrotizing soft-tissue infections (NSTI). Rural patients are at particular risk due to ...limited local resources, decreased access to care, and prolonged transport times. The aim of the current study was to examine the outcomes of NSTI requiring surgical treatment in a previously non-described setting. This retrospective study (2010-2020) from a single tertiary care center in Montana reviewed patients ≥18 years old with a NSTI via ICD9/10 codes. Rural-Urban Continuum Codes (RUCC; characterizing counties by population size) were used to distinguish urban versus rural counties. Race (White and American Indian/Alaskan Native (AI/AN)) was self-described. Qualitative and quantitative comparisons between groups were determined using the appropriate two-tailed statistical tests. An aggregate of 177 patients was identified. Mean age in AI/AN was significantly lower (
P
<0.0001) compared to White patients with no preexisting condition delineation. NSTI demonstrated an elevated incidence in both rural areas and AI/AN patients. Diabetes was also significantly higher (
P
=0.0073) in rural versus urban patients. Both rural and AI/AN patients faced extended travel distance for treatment. AI/AN patients had a significantly different infection location than White. Furthermore, polymicrobial species were significantly more prevalent in AI/AN patients. Morbidities (defined as septic shock and/or amputation) were significantly higher in AI/AN patients and rural environments (
P
<0.01). There was no significant difference in all-cause mortality between respective groups. The state of Montana presents unique challenges to optimizing NSTI treatment due to excessive distances to regional tertiary care facilities. This delay in treatment can lead to increased morbidity.
Abstract Background The purpose of this study was to analyze whether 2 standard dosing regimens of enoxaparin (30 mg twice daily vs 40 mg once daily) would result in different deep vein thrombosis ...(DVT) rates and anti-factor Xa activity (anti-Xa) in surgical patients. Methods Patients who required enoxaparin for prophylaxis were followed prospectively. Demographics were recorded. Patients underwent standardized duplex screening. Peak anti-Xa levels were drawn on 4 consecutive days. Results Sixty-three patients were followed up (28 patients on 30 mg twice daily, 35 patients on 40 mg once daily). There was no significant difference in demographics between groups. Twenty-five percent of patients on 30 mg twice daily developed a DVT, whereas 2.9% of patients on 40 mg once daily developed a DVT. Patients on 30 mg twice daily had significantly lower anti-Xa levels. Conclusions The incidence of DVT is increased in surgical patients who receive 30 mg twice daily dosing of enoxaparin compared with 40 mg daily. Dosing of 40 mg once daily results in significantly higher peak anti-Xa levels compared with 30 mg twice daily.
The incidence of deep venous thrombosis (DVT) remains high in general surgery and trauma patients despite widespread prophylaxis with enoxaparin. A recent study demonstrated decreased incidence of ...DVT if patients on enoxaparin had a change in R time (ΔR) of greater than 1 minute when heparinase-activated thromboelastography (TEG) was compared with normal TEG. We hypothesized that using ΔR-guided dosing would result in decreased DVT rates.
A prospective, randomized controlled trial was performed at a Level 1 trauma center. Both trauma and general surgery patients were included. Upon enrollment, demographic data including age, sex, body mass index, and Acute Physiology and Chronic Health Evaluation II score were obtained. Enrolled patients were randomized to standard (30 mg twice a day) or TEG-guided dosing. Dose-adjusted patients underwent daily enoxaparin titration to achieve an ΔR of 1 minute to 2 minutes. Venous thromboembolism screening was performed per institutional protocol. Antithrombin III (AT-III) and anti-Xa levels were drawn at peak enoxaparin concentrations.
A total of 87 patients were enrolled. There was no difference in demographic data between the groups. No pulmonary emboli were identified. The control group had a DVT rate of 16%, while the experimental group had a rate of 14% (p = nonsignificant). The experimental group's median enoxaparin dosage, 50 mg twice a day, was significantly higher than that of the control (p < 0.01). TEG ΔR was not different between the control and experimental groups. Beginning at Day 3, anti-Xa levels were higher in the experimental group (p < 0.05). There was no difference in AT-III activity between the two groups; 67% of the patients demonstrated AT-III deficiency.
TEG adjusted enoxaparin dosing led to significant increases in anti-Xa activity, which did not correlate with a decreased DVT rate. Failure to reduce the DVT rate and increase ΔR despite increased dosing and increased anti-Xa activity is consistent with the high rate of AT-III deficiency detected in this study cohort. These data suggest that the future of DVT prevention may not lie in the optimization of low molecular weight heparin therapy but rather in compounds that increase antithrombin directly or operate independently of the AT-III pathway.
Therapeutic study, level III.
Previous studies have shown large-volume resuscitation modulates coagulopathy and inflammation. Our objective was to analyze the effects of initial bolus fluids used in military and civilian settings ...on coagulation and inflammation in a prospective, randomized, blinded trial of resuscitation of uncontrolled hemorrhage.
Fifty swine were anesthetized, intubated, and ventilated and had monitoring lines placed. A Grade V liver injury was performed followed by 30 minutes of hemorrhage. After 30 minutes, the liver was packed, and randomized fluid resuscitation was initiated during a 12-minute period with 2 L of normal saline, 2 L of lactated Ringer's solution, 250 mL of 7.5% saline with 3% Dextran, 500 mL of Hextend, or no fluid (NF). Animals were monitored for 2 hours after injury. Thrombelastograms (TEGs), prothrombin time (PT), partial thromboplastin time, fibrinogen as well as serum interleukin 6, interleukin 8, and tumor necrosis factor α levels were drawn at baseline and after 1 hour and 2 hours.
The NF group had less posttreatment blood loss compared with other groups (p < 0.01). Blood loss was similar in the other groups. TEG R values in each group decreased from baseline at 1 and 2 hours (p < 0.02). The groups receiving 2 L of normal saline, 250 mL of 7.5% saline with 3% Dextran, or 500 mL of Hextend had lower TEG maximum amplitude values compared with NF group (p < 0.02). All fluids except lactated Ringer's solution resulted in significant increases in PT compared with NF, whereas all fluids resulted in significant decreases in fibrinogen compared with NF (p < 0.02). Fluid resuscitation groups as well as NF group demonstrated significant increases in inflammatory cytokines from baseline to 1 hour and baseline to 2 hours. There were no significant differences in inflammatory cytokines between groups at 2 hours.
Withholding fluid resulted in the least significant change in PT, fibrinogen, and maximum amplitude and in the lowest posttreatment blood loss. Resuscitation with different initial fluid resuscitation strategies did not result in increased proinflammatory mediators compared with animals that did not receive fluid.
Abstract Background Prothrombin time-international normalized ratio (PT-INR) is widely utilized to guide plasma therapy and initiation of thromboprophylaxis after a hepatectomy. Thrombelastography ...(TEG) monitors shear elasticity, which is sensitive to cellular and plasma components in blood, allowing for functional assessment of the life of the clot. The objective of this study was to prospectively compare PT-INR and TEG in liver resection patients. Methods Forty patients were enrolled before undergoing an elective hepatectomy. Patients underwent a liver resection utilizing a low central venous pressure (CVP) anaesthetic technique and intermittent Pringle manoeuver. PT-INR and TEG were drawn prior to incision, post-operatively, and post-operative days 1, 3 and 5. Results All post-operative PT-INR values increased significantly when compared with pre-operative PT-INR ( P < 0.01). The time of onset to clot ( R -value) decreased significantly at the post-operative time point ( P = 0.04), consistent with a relative hypercoagulability. Subsequent R -values were not different compared with the pre-operative R -value. The strength of the clot (maximum amplitude, MA) was unchanged when comparing pre- and post-operative time points. Discussion In spite of an elevation in PT-INR, patients undergoing a liver resection demonstrated a brief hypercoagulable state, followed by normal coagulation function based on TEG. These data call into question the practice of utilizing PT-INR to guide plasma transfusion and timing of prophylactic anticoagulation after a liver resection.
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