Pectoralis Muscle Index as Predictor of Outcomes in Patients With Severe Blunt Chest Wall Injury.

INTRODUCTION: Sarcopenia has been shown to portend worse outcomes in injured patients; however, little is known about the impact of thoracic muscle wasting on outcomes of patients with chest wall injury. We hypothesized that reduced pectoralis muscle mass is associated with poor outcomes in patients with severe blunt chest wall injury. METHODS: All patients admitted to the intensive care unit between 2014 and 2019 with blunt chest wall injury requiring mechanical ventilation were retrospectively identified. Blunt chest wall injury was defined as the presence of one or more rib fractures as a result of blunt injury mechanism. Exclusion criteria included lack of admission computed tomography imaging, penetrating trauma, <18 y of age, and primary neurologic injury. Thoracic musculature was assessed by measuring pectoralis muscle cross-sectional area (cm2) that was obtained at the fourth thoracic vertebral level using Slice-O-Matic software. The area was then divided by the patient height in meters2 to calculate pectoralis muscle index (PMI) (cm2/m2). Patients were divided into two groups, 1) the lowest gender-specific quartile of PMI and 2) second-fourth gender-specific PMI quartiles for comparative analysis. RESULTS: One hundred fifty-three patients met the inclusion criteria with a median (interquartile range) age 48 y (34-60), body mass index of 30.1 kg/m2 (24.9-34.6), and rib score of 3.0 (2.0-4.0). Seventy-five percent of patients (116/153) were male. Fourteen patients (8%) had prior history of chronic lung disease. Median (IQR) intensive care unit length-of-stay and duration of mechanical ventilation (MV) was 18.0 d (13.0-25.0) and 15.0 d (10.0-21.0), respectively. Seventy-three patients (48%) underwent tracheostomy and nine patients (6%) expired during hospitalization. On multivariate linear regression, reduced pectoralis muscle mass was associated with increased MV duration when adjusting for rib score and injury severity score (ß 5.98, 95% confidence interval 1.28-10.68, P = 0.013). CONCLUSIONS: Reduced pectoralis muscle mass is associated with increased duration of MV in patients with severe blunt chest wall injury. Knowledge of this can help guide future research and risk stratification of critically ill chest wall injury patients.

Microvesicles from stored red blood cells induce P-selectin and von Willebrand factor release from endothelial cells via a protein kinase C-dependent mechanism.

INTRODUCTION: The use of packed red blood cells (pRBCs) for resuscitation is limited by the red blood cell storage lesion, a series of biochemical and physiological changes that occur during the storage and aging of blood. Microvesicles (MVs) shed from pRBCs during this process are one component of the red blood cell storage lesion and lead to acute lung injury and pulmonary vascular microthrombi. We hypothesized that MVs from stored pRBCs lead to the release of P-selectin and von Willebrand factor (vWF) from endothelial cells and that this mechanism is mediated via activation of protein kinase C (PKC) or protein kinase A (PKA). METHODS: Leukoreduced, platelet-poor murine pRBCs were isolated from C57BL/6 8-12 week-old male mice via cardiac puncture, prepared via centrifugation using a Ficoll gradient, and stored for up to 14 days, the equivalent of 42 days of storage in humans. MVs were isolated from the stored pRBC units via sequential high-speed centrifugation. Murine lung endothelial cells (MLECs) were cultured and grown to confluence, then treated with MVs and either calphostin C, a PKC inhibitor (10 µg/mL), or PKI 14-22 amide, a PKA inhibitor (10 µM). The supernatant was collected after 1 h. P-selectin and vWF A2 concentrations were quantified via ELISA. Immunofluorescent staining for vWF was performed on MLECs. Statistical analysis was performed via unpaired t-test or ANOVA as indicated and reported as mean ± SD. Concentration is reported as pg/mL. RESULTS: MLECs treated with MVs isolated from stored pRBCs demonstrated increased release of P-selectin and vWF A2 in a dose-dependent fashion. MLECs treated with MVs prepared from stored as compared to fresh pRBCs demonstrated increased release of P-selectin (3751 ± 726 vs 359 ± 64 pg/mL, p < 0.0001) and vWF A2 (3141 ± 355 vs 977 ± 75 pg/mL, p < 0.0001) with increasing duration of storage. The treatment of MVs with calphostin C decreased the amount of P-selectin (1471 ± 444 vs 3751 ± 726 pg/mL, p < 0.0001) and VWF A2 (2401 ± 289 vs 3141 ± 355 pg/mL, p = 0.0017) released into the supernatant by MLECs compared to MVs alone. The treatment of MVs with PKI 14-22 increased the amount of P-selectin released compared to MVs alone (1999 ± 67 vs 1601 ± 135 pg/mL, p = 0.0018). CONCLUSIONS: MVs from stored pRBCs stimulate the release of P-selectin and VWF A2 from endothelial cells. The effect of MVs increases with both dose of MVs and age of stored pRBCs from which they are formed. This mechanism is dependent on activation of PKC and inhibition of this enzyme represents a potentially significant strategy to modulate the inflammatory response to resuscitation with stored pRBCs.

Whole blood storage duration alters fibrinogen levels and thrombin formation.

INTRODUCTION: Whole blood resuscitation for hemorrhagic shock in trauma represents an opportunity to correct coagulopathy in trauma while also supplying red blood cells. The production of microvesicles in stored whole blood and their effect on its hemostatic parameters have not been described in previous literature. We hypothesized that microvesicles in aged stored whole blood are procoagulant and increase thrombin production via phosphatidylserine. METHODS: Whole blood was obtained from male C57BL/6 male mice and stored in anticoagulant solution for up to 10 days. At intervals, stored whole blood underwent examination with rotational thromboelastography, and platelet-poor plasma was prepared for analysis of thrombin generation. Microvesicles were prepared from 10-day-old whole blood aliquots and added to fresh whole blood or platelet-poor plasma to assess changes in coagulation and thrombin generation. Microvesicles were treated with recombinant mouse lactadherin prior to addition to plasma to inhibit phosphatidylserine's role in thrombin generation. RESULTS: Aged murine whole blood had decreased fibrin clot formation compared with fresh samples with decreased plasma fibrinogen levels. Thrombin generation in plasma from aged blood increased over time of storage. The addition of microvesicles to fresh plasma resulted in increased thrombin generation compared with controls. When phosphatidylserine on microvesicles was blocked with lactadherin, there was no difference in the endogenous thrombin potential, but the generation of thrombin was blunted with lower peak thrombin levels. CONCLUSION: Cold storage of murine whole blood results in decreased fibrinogen levels and fibrin clot formation. Aged whole blood demonstrates increased thrombin generation, and this is due in part to microvesicle production in stored whole blood. One mechanism by which microvesicles are procoagulant is by phosphatidylserine expression on their membranes.

Sex Disparities in Academic Productivity and Rank Among Abdominal Transplant Faculty in the United States.

BACKGROUND: The aim of this study was to examine sex differences in academic rank and productivity among members of the American Society of Transplant Surgeons in the United States. METHODS: Cross-sectional, focusing on current board-certified abdominal transplant surgeons in the United States. Demographic factors such as sex, region, and faculty rank were collected from institutional websites. Academic metrics, including H-index, total publications, and relative citation ratio, were collected from Scopus and iCite. RESULTS: We identified 536 surgeon members of the American Society of Transplant Surgeons with an academic institution. The majority were men (83%). Men were in practice longer than women (17.9 ± 11 vs 11.7 ± 9 years, P < .0001) and had higher academic metrics, including H-index (25.6 ± 20 vs16.4 ± 14, P < .0001) and total publications (110 ± 145 vs 58.8 ± 69, P < .0001). There was a significant difference in faculty appointments by sex (P < .05), with men showing evidence of increased academic advancement. After adjusting for academic rank, PhD status, and location of medical school and residency, women remained associated with a lower H-index on multivariate analysis (P < .01). CONCLUSION: Sex disparities in academic rank and achievement are present among transplant surgical faculty in the United States, and future efforts are needed to promote sex equity in transplant surgery academia.

A multi-institutional study from the US ROPE consortium examining factors associated with endocrine surgery exposure for general surgery residents.

BACKGROUND: Prior analyses of general surgery resident case logs have indicated a decline in the number of endocrine procedures performed during residency. This study aimed to identify factors contributing to the endocrine operative experience of general surgery residents and compare those who matched in endocrine surgery fellowship with those who did not. METHODS: We analyzed the case log data of graduates from 18 general surgery residency programs in the US Resident Operative Experience Consortium over an 11-year period. RESULTS: Of the 1,240 residents we included, 17 (1%) matched into endocrine surgery fellowships. Those who matched treated more total endocrine cases, including more thyroid, parathyroid, and adrenal cases, than those who did not (81 vs 37, respectively, P < .01). Program-level factors associated with increased endocrine volume included endocrine-specific rotations (+10, confidence interval 8-12, P < .01), endocrine-trained faculty (+8, confidence interval 7-10, P < .01), and program co-location with otolaryngology residency (+5, confidence interval 2 -8, P < .01) or endocrine surgery fellowship (+4, confidence interval 2-6, P < .01). Factors associated with decreased endocrine volume included bottom 50th percentile in National Institute of Health funding (-10, confidence interval -12 to -8, P < .01) and endocrine-focused otolaryngologists (-3, confidence interval -4 to -1, P < .01). CONCLUSION: Several characteristics are associated with a robust endocrine experience and pursuit of an endocrine surgery fellowship. Modifiable factors include optimizing the recruitment of dedicated endocrine surgeons and the inclusion of endocrine surgery rotations in general surgery residency.

The national rate of malignancy among Bethesda III, IV, and V thyroid nodules is higher than expected: A NSQIP analysis.

BACKGROUND: The Bethesda System for Reporting Thyroid Cytopathology was formalized in 2007 to stratify cytologic specimens based on their risk of malignancy. Several studies have reported significant variations between their institutional rate of malignancy compared to the Bethesda System for Reporting Thyroid Cytopathology. The objective of this study was to determine the national rate of malignancy for Bethesda III, Bethesda IV, and Bethesda V thyroid nodules. METHODS: From 2016 to 2019, patients with preoperative thyroid cytopathology and pathology results in National Surgical Quality Improvement database were included. The rate of malignancy was compared to the median the Bethesda System for Reporting Thyroid Cytopathology 2017, and risk factors associated with malignancy were identified for Bethesda III, Bethesda IV, and Bethesda V specimens. RESULTS: In total, 13,121 patients with preoperative cytopathology and postresection pathology were identified. The national rate of malignancy was significantly higher than the Bethesda System for Reporting Thyroid Cytopathology 2017 for Bethesda III (36.2% vs 12.0%, P < .01), Bethesda IV (36.7% vs 25.0%, P < .01), and Bethesda V (91.1% vs 52.5%, P < .01) specimens. Male sex was significantly associated with malignancy in Bethesda III, Bethesda IV, and Bethesda V nodules (Bethesda III, odds ratio: 1.20, [1.01-1.42]; Bethesda IV, odds ratio: 1.47, [1.27-1.71]; Bethesda V, odds ratio: 1.28, [1.03-1.58]). Younger age was associated with malignancy in Bethesda III patients under 55 (odds ratio: 1.23, [1.06-1.42]), Bethesda IV patients under 42 (odds ratio: 1.23, [1.06-1.43]), and Bethesda V patients aged less than 47 (odds ratio: 1.38, [1.15-1.67]). CONCLUSIONS: This is the largest cohort study to describe the national rate of malignancy for Bethesda III, IV, and V specimens in the United States. These results reveal the national rate of malignancy is higher than the implied rate of malignancy reported to patients based on the Bethesda System for Reporting Thyroid Cytopathology. We recommend counseling patients regarding this increased rate of malignancy to set appropriate expectations after surgical intervention.

Experience of surgical subspecialty residents on general surgery rotations.

BACKGROUND: Surgical subspecialty residents complete 5-6 years of training which includes general surgery rotations. A lack of data exists evaluating these rotations. This study aims to identify discrepancies in subspecialty training and improve the quality of surgical education. METHODS: Case logs for surgical subspecialty residents and general surgery residents at our institution were analyzed and queried for cases performed on general surgery rotations. A survey was distributed to subspecialty residents regarding their perceptions of these rotations. RESULTS: 50 residents were included in the study and the majority were male (n = 27, 54%). Subspecialty residents perform fewer cases per month compared to general surgery residents (13 vs 21, p < 0.001). 75% of subspecialty residents were satisfied with their experience on general surgery rotations. CONCLUSIONS: Subspecialty residents perform fewer operations on general surgery rotations. Despite this, most are satisfied with off-service rotations and believe they are an important part of their education.

Biophysiological stress and sleep deprivation among abdominal transplant surgery fellows: A prospective multi-institutional study using a wearable device.

BACKGROUND: Transplant surgery fellowship is physically and emotionally demanding. The objective of this study was to characterize biophysiological stress and sleep patterns among transplant surgery fellows. METHODS: Participating fellows wore a biophysical monitor over a 28-day period and completed biweekly surveys. Sleep patterns were dichotomized as normal or sleep deprived, and heart rate variability (HRV) was used to assess stress. RESULTS: Seventeen fellows participated. Fellows were frequently sleep deprived (43.9% of nights) and stress was near universal (87.2% of days). Burnout was reported by 2 fellows (11.8%). Only 4 fellows (23.5%) reported compliance with the Transplant Accreditation and Certification Council managed time policy; these fellows experienced fewer days of stress than non-compliant fellows (79.8% vs 89.2% p = 0.02). CONCLUSIONS: This is the first study to quantify sleep deprivation and stress among transplant fellows. Future work is needed to evaluate the effects of sleep deprivation, and stress on burnout and patient outcomes.

Long-term follow-up of temporary abdominal closure in complex abdomens during liver transplant.

BACKGROUND: Temporary abdominal closure is commonly employed in liver transplantation when patient factors make primary fascial closure challenging. However, there is minimal data evaluating long-term survival and patient outcomes after temporary abdominal closure. METHODS: A single-center, retrospective review of patients undergoing liver transplantation from January 2013 through December 2017 was performed with a 5-year follow-up. Patients were characterized as either requiring temporary abdominal closure or immediate primary fascial closure at the time of liver transplantation. RESULTS: Of 422 patients who underwent 436 liver transplantations, 17.2% (n = 75) required temporary abdominal closure, whereas 82.8% (n = 361) underwent primary fascial closure. Patients requiring temporary abdominal closure had higher Model for End-Stage Liver Disease scores preoperatively (27 [22-36] vs 23 [20-28], P = .0002), had higher rates of dialysis preoperatively (28.0% vs 12.5%, P = .0007), and were more likely to be hospitalized within 90 days of liver transplantation (64.0% vs 47.5%, P = .0093). On univariable analysis, survival at 1 year was different between the groups (90.9% surviving at 1 year for primary fascial closure versus 82.7% for temporary abdominal closure, P = .0356); however, there was no significant difference in survival at 5 years (83.7% vs 76.0%, P = .11). On multivariable analysis, there was no difference in survival after adjusting for multiple factors. Patients requiring temporary abdominal closure were more likely to have longer hospital stays (median 16 days [9.75-29.5] vs 8 days [6-14], P < .0001), more likely to be readmitted within 30 days (45.3% vs 32.2%, P = .03), and less likely to be discharged home (36.5% vs 74.2%, P < .0001). CONCLUSIONS: Temporary abdominal closure after liver transplantation appears safe and has similar outcomes to primary fascial closure, though it is used more commonly in complex patients.