Splenic artery loops: Potential splenic plexus stimulation sites for neuroimmunomodulatory-based anti-inflammatory therapy?

INTRODUCTION: The splenic plexus might represent a novel neuroimmunomodulatory therapeutic target as electrical stimulation of this tissue has been shown to have beneficial anti-inflammatory effects. Tortuous splenic artery segments (splenic artery loops), including their surrounding nerve plexus, have been evaluated as potential stimulation sites in humans. At present, however, our understanding of these loops and their surrounding nerve plexus is incomplete. This study aims to characterize the dimensions of these loops and their surrounding nerve tissue. MATERIALS AND METHODS: Six formaldehyde fixed human cadavers were dissected and qualitative and quantitative macro- and microscopic data on splenic artery loops and their surrounding nerve plexus were collected. RESULTS: One or multiple loops were observed in 83% of the studied specimens. These loops, including their surrounding nerve plexus could be easily dissected free circumferentially thereby providing sufficient space for further surgical intervention. The splenic plexus surrounding the loops contained a significant amount of nerves that contained predominantly sympathetic fibers. CONCLUSION: The results of this study support that splenic artery loops could represent suitable electrical splenic plexus stimulation sites in humans. Dimensions with respect to loop height and width, provide sufficient space for introduction of surgical instruments and electrode implantation, and, the dissected neurovascular bundles contain a substantial amount of sympathetic nerve tissue. This knowledge may contribute to further development of surgical techniques and neuroelectrode interface design.

Morphometric analysis of the splenic artery using contrast-enhanced computed tomography (CT).

PURPOSE: To evaluate the morphology and course of the splenic artery, which might impact the surgical implantation of systems that stimulate the nerves surrounding the splenic artery. Experimental studies indicate that these nerves play an important part in immune modulation, and might be a potential target in the treatment of autoimmune diseases. METHODS: This retrospective cohort study made use of contrast-enhanced CT images from 40 male and 40 female patients (age 30-69) that underwent a CT examination of the aorta, kidneys or pancreas. Anatomic features were described including total splenic artery length, calibers, tortuosity, the presence of arterial loops and the branching pattern of the splenic artery. RESULTS: No age-gender-related differences could be found related to tortuosity or branching pattern. The length of splenic artery in contact with pancreatic tissue decreased with increasing age, but was not different between genders. Artery diameters were wider in male compared to female subjects. Loops of variable directions, that represent a part of the artery that curls out of the pancreatic tissue, were identified in each age-gender category and were present in nearly all subjects (86%). CONCLUSION: This study suggests that although some anatomic features of the splenic artery are subject to factors as age and gender, the tortuosity of the splenic artery is not age dependent. Most subjects had one or multiple loops, which can serve as a target for neuromodulatory devices. Future studies should investigate whether splenic nerve stimulation is safe and feasible.

Non-weight-based enoxaparin dosing subtherapeutic in trauma patients.

BACKGROUND: We report our experience dosing and monitoring enoxaparin with anti-factor Xa activity (anti-FXaA) levels for venous thromboembolism prophylaxis in trauma patients (TP). MATERIALS AND METHODS: TP receiving standard, non-weight-based dosed enoxaparin administered every 12 h for venous thromboembolism prophylaxis with peak anti-FXaA levels measured were prospectively monitored and evaluated and those whose first anti-FXaA levels ≥ or <0.2 IU/mL were compared. Anti-FXaA levels and enoxaparin dose (mg/kg actual body weight) were evaluated for correlation. RESULTS: Of the fifty-one TP included, initial anti-FXaA levels were <0.2 IU/mL in 37 (72.5%) whose dose was lower than those within target range (0.38 [0.32-0.42] mg/kg versus 0.45 [0.39-0.48] mg/kg, P = 0.003). Thirty-seven TP achieved anti-FXaA level ≥0.2 IU/mL (23 requiring dose increases) at a dose of 0.49 [0.44-0.54] mg/kg. Correlation between dose and anti-FXaA levels for the initial 51 anti-FXaA levels (r = 0.360, P = 0.009) and for all 103 anti-XaA levels (r = 0.556, P < 0.001) was noted. CONCLUSIONS: Non-weight-based enoxaparin dosing did not achieve target anti-FXaA levels in most TP. Higher anti-FXaA levels correlated with larger weight-based enoxaparin doses. Weight-based enoxaparin dosing (i.e., 0.5 mg/kg subcutaneously every 12 h) would better achieve target anti-FXaA levels.

Chronic baroreflex activation restores spontaneous baroreflex control and variability of heart rate in obesity-induced hypertension.

The sensitivity of baroreflex control of heart rate is depressed in subjects with obesity hypertension, which increases the risk for cardiac arrhythmias. The mechanisms are not fully known, and there are no therapies to improve this dysfunction. To determine the cardiovascular dynamic effects of progressive increases in body weight leading to obesity and hypertension in dogs fed a high-fat diet, 24-h continuous recordings of spontaneous fluctuations in blood pressure and heart rate were analyzed in the time and frequency domains. Furthermore, we investigated whether autonomic mechanisms stimulated by chronic baroreflex activation and renal denervation-current therapies in patients with resistant hypertension, who are commonly obese-restore cardiovascular dynamic control. Increases in body weight to ∼150% of control led to a gradual increase in mean arterial pressure to 17 ± 3 mmHg above control (100 ± 2 mmHg) after 4 wk on the high-fat diet. In contrast to the gradual increase in arterial pressure, tachycardia, attenuated chronotropic baroreflex responses, and reduced heart rate variability were manifest within 1-4 days on high-fat intake, reaching 130 ± 4 beats per minute (bpm) (control = 86 ± 3 bpm) and ∼45% and <20%, respectively, of control levels. Subsequently, both baroreflex activation and renal denervation abolished the hypertension. However, only baroreflex activation effectively attenuated the tachycardia and restored cardiac baroreflex sensitivity and heart rate variability. These findings suggest that baroreflex activation therapy may reduce the risk factors for cardiac arrhythmias as well as lower arterial pressure.

Splenic arterial neurovascular bundle stimulation in esophagectomy: A feasibility and safety prospective cohort study.

Introduction: The autonomic nervous system is a key regulator of inflammation. Electrical stimulation of the vagus nerve has been shown to have some preclinical efficacy. However, only a few clinical studies have been reported to treat inflammatory diseases. The present study evaluates, for the first time, neuromodulation of the splenic arterial neurovascular bundle (SpA NVB) in patients undergoing minimally invasive esophagectomy (MIE), in which the SpA NVB is exposed as part of the procedure. Methods: This single-center, single-arm study enrolled 13 patients undergoing MIE. During the abdominal phase of the MIE, a novel cuff was placed around the SpA NVB, and stimulation was applied. The primary endpoint was the feasibility and safety of cuff application and removal. A secondary endpoint included the impact of stimulation on SpA blood flow changes during the stimulation, and an exploratory point was C-reactive protein (CRP) levels on postoperative day (POD) 2 and 3. Results: All patients successfully underwent placement, stimulation, and removal of the cuff on the SpA NVB with no adverse events related to the investigational procedure. Stimulation was associated with an overall reduction in splenic arterial blood flow but not with changes in blood pressure or heart rate. When compared to historic Propensity Score Matched (PSM) controls, CRP levels on POD2 (124 vs. 197 mg/ml, p = 0.032) and POD3 (151 vs. 221 mg/ml, p = 0.033) were lower in patients receiving stimulation. Conclusion: This first-in-human study demonstrated for the first time that applying a cuff around the SpA NVB and subsequent stimulation is safe, feasible, and may have an effect on the postoperative inflammatory response following MIE. These findings suggest that SpA NVB stimulation may offer a new method for immunomodulatory therapy in acute or chronic inflammatory conditions.

Comparison of sagittal T2-weighted BLADE and fast spin-echo MRI of the female pelvis for motion artifact and lesion detection.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of BLADE (proprietary name for periodically rotated overlapping parallel lines with enhanced reconstruction [PROPELLER] in MR systems from Siemens Healthcare) MRI compared with conventional T2-weighted fast spin-echo (FSE) MRI for reducing artifacts and improving image quality when imaging the female pelvis. MATERIALS AND METHODS: Sagittal T2-weighted BLADE and FSE examinations of the pelvis of 26 women were performed on a 1.5-T scanner. Three radiologists assessed the images for the presence of artifacts, level of anatomic detail, and overall image quality using a modified Likert scale. Scores for each radiologist and each imaging sequence were analyzed with a linear mixed model, adjusting for correlation within radiologist and within patient. A quantitative comparison was conducted to investigate signal uniformity. RESULTS: The BLADE sequence was superior for evaluation of the junctional zone (p = 0.0019), delineation of ovarian borders and depiction of follicles (p < 0.0001), and detection of fibroids (p = 0.022). Overall image quality was improved with BLADE, with fewer respiratory motion artifacts. The BLADE sequence introduced "radial" artifact that was absent from the FSE images, but this artifact did not affect image quality. Quantitative analysis revealed mean coefficients of variation for BLADE and FSE in the uterus of 21.6% and 22.5%, respectively (p = 0.36). The mean coefficients of variation were 4.6% and 6.1% in fat (p = 0.0007), indicating less variation with BLADE. The mean acquisition times for the BLADE and FSE sequences were 4 minutes 31 seconds and 3 minutes 46 seconds, respectively. CONCLUSION: Imaging of uterine junctional zone anatomy, ovaries, and fibroids was improved and artifacts were reduced with BLADE compared with FSE. Radial artifact introduced by the BLADE sequence and slightly longer imaging times needed for the BLADE sequence were offset by improved image quality.

Prothrombin complex concentrate versus standard therapies for INR reversal in trauma patients receiving warfarin.

BACKGROUND: Prothrombin complex concentrate (PCC) is recommended as a therapy to be considered for the reversal of warfarin's effects. Few published data are available on the use of PCC for this indication in traumatically injured patients. OBJECTIVE: To determine whether the addition of PCC to standard approaches to warfarin reversal more rapidly corrects the international normalized ratio (INR) in injured patients. METHODS: A retrospective analysis was performed in trauma patients who were on warfarin preinjury from January 2007 to September 2009 at North Memorial Medical Center. Data were collected from medical records and the trauma registry. Patients were separated based on whether or not they received PCC. The groups were compared on the basis of demographics, units of fresh frozen plasma (FFP), vitamin K use, units of PCC, number of patients achieving an INR of 1.5 or less, time to an INR of 1.5 or less, mortality, intensive care unit (ICU) and hospital length of stay, and the incidence of thromboembolic events during hospitalization. RESULTS: Thirty-one patients were included in the analysis; 13 patients who received a total mean (SD) dose of 2281 (1053) units (25.6 [12.2] units/kg) of PCC (Profilnine SD) were compared to 18 patients who did not receive PCC. There was no significant difference between groups in FFP units received or the number of patients who received vitamin K. Most patients in both groups achieved an INR of 1.5 or less (92% PCC vs 89% no PCC). However, the mean time to achieve an INR of 1.5 or less was 16:59 (20:53) hours in the PCC group versus 30:03 (23:10) hours in the no PCC group (p = 0.048). There were 3 deaths in the PCC group and no deaths in the no PCC group (p = 0.06). ICU and hospital length of stay and number of thromboembolic events did not differ significantly between the 2 groups. CONCLUSIONS: PCC, when added to FFP and vitamin K, resulted in a more rapid time to reversal of the INR.

Implantation of a carotid baroreceptor stimulator in patients with pacemakers and hypertension.

BACKGROUND: The Rheos® System (CVRx, Minneapolis, MN, USA) is an implantable device used to lower blood pressure in patients with resistant hypertension by stimulation of the carotid baroreceptors. It is unknown if interaction might exist between Rheos and conventional pacemakers. METHODS: Compatibility of the Rheos device was tested in four patients with preexisting pacemakers. Intra- and postoperative testing was completed with pacemaker and Rheos settings programmed to provoke interaction. Intracardiac electrograms were printed to determine interaction with the pacemaker. RESULTS: No interaction was observed at maximum atrial and ventricular sensitivity settings and maximum bilateral Rheos output settings. CONCLUSION: Concomitant device therapy with Rheos device and pacemakers can be achieved without interaction.

Repair of high-risk incisional hernias and traumatic abdominal wall defects with porcine mesh.

Complex ventral hernias represent a significant challenge to surgeons. We hypothesized that a wide underlay technique in combination with a novel biologic mesh would result in repair with a low recurrence rate. Medical records of patients undergoing ventral herniorrhaphy with XenMatrix biologic mesh were evaluated. All patients were evaluated for hernia recurrence both immediately and after 2 to 3 years. There were 57 patients included in the study. The overall recurrence rate was 7.2 per cent; however, all recurrences were early and were likely technical failures. The average duration of follow-up was 30.6 months with no further recurrences after the early technical failures. The average number of previous recurrences was 1.5. Fascial closure was obtained over the mesh in 84 per cent of patients, with component separation being necessary in 36 per cent of patients. Lack of fascial reapproximation over the mesh was associated with early recurrence (0 vs 55%, P < 0.0001). Complex ventral hernias can be repaired with a low recurrence rate. Our technique in combination with the XenMatrix biologic mesh provides for durable repair. Whenever possible, the fascia should be closed above the underlay mesh, because this technique provides a more durable repair than using the mesh as a "fascial bridge".

An Interprofessional Senior Medical Student Preparation Course: Improvement in Knowledge and Self-Confidence Before Entering Surgical Training.

PURPOSE: Senior medical students are variably prepared to begin surgical training; and a national curriculum was established through the American College of Surgeons to better prepare senior medical students for surgical training. The purpose of our course is to prepare senior medical students to more effectively enter surgical training programs. We recently enhanced our independently developed surgical training preparation course by increasing exposure to surgical anatomy, medical physiology, surgical skills, and point-of-care ultrasound. We evaluated the impact of our interprofessional training course to increase confidence and readiness among senior medical students entering surgical training. METHODS: The course focused on pre- and post-operative patient care, surgical anatomy, human physiology, and bedside ultrasound. Didactic lectures in anatomy, human physiology, and bedside ultrasound were provided prior to all hands-on simulated patient care sessions and mock surgical procedures. To evaluate our interprofessional curriculum, we administered pre- and post-course surveys, pre- and post-course knowledge tests, and a final surgical anatomy laboratory practical examination to 22 senior medical students who were enrolled in the course. All students created a final surgical anatomy presentation. RESULTS: The students demonstrated a 100% pass rate in surgical anatomy. The knowledge test, which included assessment of knowledge on perioperative surgical decision making, human physiology, and bedside ultrasound, demonstrated an average improvement of 10%. Statistically significant improvements in median confidence values were identified in 10 of 32 surveyed categories, including surgical skills (p < 0.05); 84% of student goals for the course were achieved. The medical students' surveys confirmed increased confidence related to the use of point-of-care ultrasound, teamwork experience, and basic surgical skills through small group interactive seminars and surgical simulation exercises. CONCLUSION: Our preparation for surgical training course resulted in high student satisfaction and demonstrated an increased sense of confidence to begin surgical training. The 10% improvement in medical student knowledge, as evaluated by a written examination, and the significant improvement in confidence level self-assessment scores confirms this surgery preparation course for senior medical students successfully achieved the desired goals of the course.

Sustained suppression of sympathetic activity and arterial pressure during chronic activation of the carotid baroreflex.

Following sinoaortic denervation, which eliminates arterial baroreceptor input into the brain, there are slowly developing adaptations that abolish initial sympathetic activation and hypertension. In comparison, electrical stimulation of the carotid sinus for 1 wk produces sustained reductions in sympathetic activity and arterial pressure. However, whether compensations occur subsequently to diminish these responses is unclear. Therefore, we determined whether there are important central and/or peripheral adaptations that diminish the sympathoinhibitory and blood pressure-lowering effects of more sustained carotid sinus stimulation. To this end, we measured whole body plasma norepinephrine spillover and alpha(1)-adrenergic vascular reactivity in six dogs over a 3-wk period of baroreflex activation. During the first week of baroreflex activation, there was an approximately 45% decrease in plasma norepinephrine spillover, along with reductions in mean arterial pressure and heart rate of approximately 20 mmHg and 15 beats/min, respectively; additionally, plasma renin activity did not increase. Most importantly, these responses during week 1 were largely sustained throughout the 3 wk of baroreflex activation. Acute pressor responses to alpha-adrenergic stimulation during ganglionic blockade were similar throughout the study, indicating no compensatory increases in adrenergic vascular reactivity. These findings indicate that the sympathoinhibition and lowering of blood pressure and heart rate induced by chronic activation of the carotid baroreflex are not diminished by adaptations in the brain and peripheral circulation. Furthermore, by providing evidence that baroreflexes have long-term effects on sympathetic activity and arterial pressure, they present a perspective that is opposite from studies of sinoaortic denervation.

Implantable carotid sinus stimulator for the treatment of resistant hypertension: local effects on carotid artery morphology.

BACKGROUND: The Rheos System is a chronically implanted carotid sinus baroreflex activating system with a pulse generator and bilateral perivascular carotid sinus leads (CSLs) that is being evaluated in prospective clinical trials for the treatment of drug-resistant hypertension. We evaluated carotid artery structural integrity after implantation of the CSLs. METHODS: To assess the effect of chronic CSL attachment, 29 CSLs were implanted on the common carotid arteries of eight sheep. The studies were terminated at 3 and 6 months postimplantation to assess anatomic and histologic changes. Additionally, 10 patients with resistant hypertension were enrolled in the Rheos Multicenter Feasibility Trial. Duplex ultrasound (DUS) was performed before device implantation and at 1 and 4 months postimplantation in this patient cohort. An independent core laboratory assessed all DUSs. RESULTS: Ovine carotid angiography revealed no significant stenoses, while anatomic and histologic evaluations demonstrated electrode encapsulation in a thin layer of connective tissue with no evidence of stenosis, erosion, or inflammation. DUS evaluation revealed no significant increase in peak systolic velocities of the common and internal carotid arteries 1 and 4 months after initial implantation, indicating a lack of injury, remodeling, or stenosis. CONCLUSION: The current data suggest that the CSLs used with the Rheos System are not associated with the development of carotid stenosis or injury. These short-term data support the concept of CSL placement and merit long-term investigation in a larger multicenter prospective trial.

A systematic method for follow-up improves removal rates for retrievable inferior vena cava filters in a trauma patient population.

BACKGROUND: Retrievable inferior vena cava filters (rIVCF) reduce the short-term risk of pulmonary embolism without the filter and inferior vena cava (IVC) thrombosis that have been reported with the use of permanent filters. Studies have shown that most rIVCFs are not removed, leaving patients at risk for thrombotic complications of rIVCF retention. We hypothesize that the application of a systematic follow-up for rIVCF will improve filter removal rates, providing patients short-term prophylaxis from pulmonary embolism whereas avoiding complications of permanent filter retention. METHODS: The trauma registry of a Level I trauma center was queried to identify patients who underwent placement of IVCFs between January 1, 2003, and June 30, 2008. The medical records were reviewed and details of the patient's injuries, indications for filter placement, repositioning, and retrieval were collected. Radiographic images were reviewed to confirm ultimate filter retention or removal. RESULTS: Between January 1, 2003, and June 30, 2008, rIVCFs were placed in 118 patients, 44% had known venous thromboembolic event. Three patients died before rIVCFs could be considered for extraction, leaving 115 patients for evaluation. Filters were removed in 80 patients (70%) overall. Of the 35 patients in whom filters were not removed, 11 were lost to follow-up, 4 failed removal attempts, and 20 had indications for filter retention. The rIVCFs were retrieved in 75% of patients not lost to follow-up and 92% of patients who did not have contraindications for filter removal. CONCLUSION: A dedicated system for following-up patients with rIVCFs markedly improves removal rates of retrievable filters.

A trauma outreach program provided by a level I trauma center is an effective way to initiate peer review at referring hospitals and foster process improvements.

BACKGROUND: The initial care of critically injured patients has profound effects on ultimate outcomes. The "golden hour" of trauma care is often provided by rural hospitals before definitive transfer. There are, however, no standardized methods for providing educational feedback to these hospitals for the purposes of performance improvement. We hypothesized that an outreach program would stimulate peer review and identify systematic deficiencies in the care of patients with injuries. METHODS: We developed a quality improvement program aimed at providing educational feedback to hospitals that referred patients to our American College of Surgeons-verified level I trauma center. We traveled to each referral center to provide feedback on the initial treatment and ultimate outcome of patients that were transferred to us. These feedback sessions were presented in the format of case presentations and case discussions. RESULTS: The outreach program was presented at each hospital every 3 months to 6 months. Nine hospitals were included in our program. We received 334 patients in transfer from these hospitals during the study period. Formal peer review that focused on trauma patients increased from 14% of hospitals to 100% of hospitals after institution of the program. Eighty-five percent of hospitals thought that the care of patients with injuries was improved as a result of the program. Eighty-five percent of hospitals developed process improvement initiatives as a result of the program. CONCLUSIONS: A formal outreach program can stimulate peer review at rural hospitals, provide continuing education in the care of patients with injuries, and foster process improvements at referring hospitals.

Reducing complications in trauma patients: use of a standardized quality improvement approach.

Injured patients are especially prone to developing complications. Using a multidisciplinary standardized approach to complication review is an effective method of evaluating quality improvement in patients on the trauma service. Collaboration between trauma surgeons and nurse clinicians is instrumental in improving the care of patients in each of the areas we identified. Using this consistently, quality improvement strategies can be put in place and tracked for outcomes. This has allowed for better quantification of the problem as well as any change that may result from applying this formal review process and subsequent intervention.

Acute and critical care management of a pediatric patient with medullo-cerebellar impaling.

The authors present a child with an accidental cervical medullo-cerebellar impaling by an aluminum rod. Careful planning for safe removal of the rod as well as vigilant attention to early cardiac instability and flash neurogenic pulmonary edema were paramount to her successful recovery. This patient illustrates that it is possible to survive impaling of the brainstem but it requires both innovation and collaboration by multiple specialists across different departments. The value of well coordinated and collaborative neuro surgical intensive care is demonstrated in this young girl's nearly complete recovery from the accident.

Prolonged Baroreflex Activation Abolishes Salt-Induced Hypertension After Reductions in Kidney Mass.

Chronic electric activation of the carotid baroreflex produces sustained reductions in sympathetic activity and arterial pressure and is currently being evaluated for therapy in patients with resistant hypertension. However, patients with significant impairment of renal function have been largely excluded from clinical trials. Thus, there is little information on blood pressure and renal responses to baroreflex activation in subjects with advanced chronic kidney disease, which is common in resistant hypertension. Changes in arterial pressure and glomerular filtration rate were determined in 5 dogs after combined unilateral nephrectomy and surgical excision of the poles of the remaining kidney to produce ≈70% reduction in renal mass. After control measurements, sodium intake was increased from ≈45 to 450 mol/d. While maintained on high salt, animals experienced increases in mean arterial pressure from 102±4 to 121±6 mm Hg and glomerular filtration rate from 40±2 to 45±2 mL/min. During 7 days of baroreflex activation, the hypertension induced by high salt was abolished (103±6 mm Hg) along with striking suppression of plasma norepinephrine concentration from 139±21 to 81±9 pg/mL, but despite pronounced blood pressure lowering, there were no significant changes in glomerular filtration rate (43±2 mL/min). All variables returned to prestimulation values during a recovery period. These findings indicate that after appreciable nephron loss, chronic suppression of central sympathetic outflow by baroreflex activation abolishes hypertension induced by high salt intake. The sustained antihypertensive effects of baroreflex activation occur without significantly compromising glomerular filtration rate in remnant nephrons.

Wells criteria for DVT is a reliable clinical tool to assess the risk of deep venous thrombosis in trauma patients.

BACKGROUND: Deep Vein Thrombosis (DVT) is a common complication in trauma patients. Venous duplex surveillance is used widely for the diagnosis of DVT, however, there is controversy concerning its appropriate use. The Wells criterion is a clinically validated scoring system in an outpatient setting, but its use in trauma patients has not been studied. This study evaluated the application of the Wells scoring system in trauma population. METHODS: Wells scores were calculated retrospectively for all patients who were admitted to the trauma service and underwent Venous Duplex Scanning (VDS) at the author's institution between 2012 and 2013. Correlation of Wells score with DVT and its efficacy in risk stratifying the patients after trauma was analyzed using linear correlation and receiver operating characteristic (ROC) curve. Sensitivity and specificity of Wells score in ruling out or ruling in DVT were calculated in various risk groups. RESULTS: Of 298 patients evaluated, 18 (6 %) patients were positive for DVT. A linear correlation was present between Wells score and DVT with R (2) = 0.88 (p = 0.0016). Median Wells score of patients without DVT was 1 (1-3) compared to a median score of 2 (1-5) in those with DVT (p < 0.0001). In low risk patients (scores <1), Wells scoring was able to rule out the possibility of DVT with a sensitivity of 100 % and NPV of 100 %, while in moderate-high risk patients (scores ≥2), it was able to predict DVT with a specificity of 90 %. Area under ROC curve was 0.859 (p < 0.0001) demonstrating the accuracy of Wells scoring system for DVT risk stratification in post trauma patients. CONCLUSIONS: A Wells score of <1 can reliably rule out the possibility of DVT in the trauma patients. Risk of developing DVT correlates linearly with Wells score, establishing it as a valid pretest tool for risk stratification.

Chronic Interactions Between Carotid Baroreceptors and Chemoreceptors in Obesity Hypertension.

Carotid bodies play a critical role in protecting against hypoxemia, and their activation increases sympathetic activity, arterial pressure, and ventilation, responses opposed by acute stimulation of the baroreflex. Although chemoreceptor hypersensitivity is associated with sympathetically mediated hypertension, the mechanisms involved and their significance in the pathogenesis of hypertension remain unclear. We investigated the chronic interactions of these reflexes in dogs with sympathetically mediated, obesity-induced hypertension based on the hypothesis that hypoxemia and tonic activation of carotid chemoreceptors may be associated with obesity. After 5 weeks on a high-fat diet, the animals experienced a 35% to 40% weight gain and increases in arterial pressure from 106±3 to 123±3 mm Hg and respiratory rate from 8±1 to 12±1 breaths/min along with hypoxemia (arterial partial pressure of oxygen=81±3 mm Hg) but eucapnia. During 7 days of carotid baroreflex activation by electric stimulation of the carotid sinus, tachypnea was attenuated, and hypertension was abolished before these variables returned to prestimulation values during a recovery period. After subsequent denervation of the carotid sinus region, respiratory rate decreased transiently in association with further sustained reductions in arterial partial pressure of oxygen (to 65±2 mm Hg) and substantial hypercapnia. Moreover, the severity of hypertension was attenuated from 125±2 to 116±3 mm Hg (45%-50% reduction). These findings suggest that hypoxemia may account for sustained stimulation of peripheral chemoreceptors in obesity and that this activation leads to compensatory increases in ventilation and central sympathetic outflow that contributes to neurogenically mediated hypertension. Furthermore, the excitatory effects of chemoreceptor hyperactivity are abolished by chronic activation of the carotid baroreflex.