The impact of post-operative enteral nutrition on duodenal injury outcomes: A post hoc analysis of an EAST multicenter trial

BACKGROUND

Leak following surgical repair of traumatic duodenal injuries results in prolonged hospitalization and oftentimes nil per os(NPO) treatment. Parenteral nutrition(PN) has known morbidity; however, duodenal leak(DL) patients often have complex injuries and hospital courses resulting in barriers to enteral nutrition(EN). We hypothesized EN alone would be associated with 1)shorter duration until leak closure and 2)less infectious complications and shorter hospital length of stay(HLOS) compared to PN.

METHODS

This was a post-hoc analysis of a retrospective, multicenter study from 35 Level-1 trauma centers, including patients >14 years-old who underwent surgery for duodenal injuries(1/2010-12/2020) and endured post-operative DL. The study compared nutrition strategies: EN vs PN vs EN + PN using Chi-Square and Kruskal-Wallis tests; if significance was found pairwise comparison or Dunn's test were performed.

RESULTS

There were 113 patients with DL: 43 EN, 22 PN, and 48 EN + PN. Patients were young(median age 28 years-old) males(83.2%) with penetrating injuries(81.4%). There was no difference in injury severity or critical illness among the groups, however there were more pancreatic injuries among PN groups. EN patients had less days NPO compared to both PN groups(12 days[IQR23] vs 40[54] vs 33[32],p = <0.001). Time until leak closure was less in EN patients when comparing the three groups(7 days[IQR14.5] vs 15[20.5] vs 25.5[55.8],p = 0.008). EN patients had less intra-abdominal abscesses, bacteremia, and days with drains than the PN groups(all p < 0.05). HLOS was shorter among EN patients vs both PN groups(27 days[24] vs 44[62] vs 45[31],p = 0.001). When controlling for predictors of leak, regression analysis demonstrated EN was associated with shorter HLOS(β -24.9, 95%CI -39.0 to -10.7,p < 0.001).

CONCLUSION

EN was associated with a shorter duration until leak closure, less infectious complications, and shorter length of stay. Contrary to some conventional thought, PN was not associated with decreased time until leak closure. We therefore suggest EN should be the preferred choice of nutrition in patients with duodenal leaks whenever feasible.

LEVEL OF EVIDENCE

IV.

A western trauma association multicenter comparison of mesh versus non-mesh repair of blunt traumatic abdominal wall hernias

BACKGROUND

Blunt traumatic abdominal wall hernias (TAWH) occur in <1 % of trauma patients. Optimal repair techniques, such as mesh reinforcement, have not been studied in detail. We hypothesize that mesh use will be associated with increased surgical site infections (SSI) and not improve hernia recurrence.

MATERIALS AND METHODS

A secondary analysis of the Western Trauma Association blunt TAWH multicenter study was performed. Patients who underwent TAWH repair during initial hospitalization (1/2012-12/2018) were included. Mesh repair patients were compared to primary repair patients (non-mesh). A logistic regression was conducted to assess risk factors for SSI.

RESULTS

157 patients underwent TAWH repair during index hospitalization with 51 (32.5 %) having mesh repair: 24 (45.3 %) synthetic and 29 (54.7 %) biologic. Mesh patients were more commonly smokers (43.1 % vs. 22.9 %, p = 0.016) and had a larger defect size (10 vs. 6 cm, p = 0.003). Mesh patients had a higher rate of SSI (25.5 % vs. 9.5 %, p = 0.016) compared to non-mesh patients, but a similar rate of recurrence (13.7 % vs. 10.5%, p = 0.742), hospital length of stay (LOS), and mortality. Mesh use (OR 3.66) and higher ISS (OR 1.06) were significant risk factors for SSI in a multivariable model.

CONCLUSION

Mesh was used more frequently in flank TAWH and those with a larger defect size. Mesh use was associated with a higher incidence and risk of SSI but did not reduce the risk of hernia recurrence. When repairing TAWH mesh should be employed judiciously, and prospective randomized studies are needed to identify clear indications for mesh use in TAWH.

Mutate and Conjugate: A Method to Enable Rapid In-Cell Target Validation

Target validation remains a challenge in drug discovery, which leads to a high attrition rate in the drug discovery process, particularly in Phase II clinical trials. Consequently, new approaches to enhance target validation are valuable tools to improve the drug discovery process. Here, we report the combination of site-directed mutagenesis and electrophilic fragments to enable the rapid identification of small molecules that selectively inhibit the mutant protein. Using the bromodomain-containing protein BRD4 as an example, we employed a structure-based approach to identify the L94C mutation in the first bromodomain of BRD4 [BRD4(1)] as having a minimal effect on BRD4(1) function. We then screened a focused, KAc mimic-containing fragment set and a diverse fragment library against the mutant and wild-type proteins and identified a series of fragments that showed high selectivity for the mutant protein. These compounds were elaborated to include an alkyne click tag to enable the attachment of a fluorescent dye. These clickable compounds were then assessed in HEK293T cells, transiently expressing BRD4(1)WT or BRD4(1)L94C, to determine their selectivity for BRD4(1)L94C over other possible cellular targets. One compound was identified that shows very high selectivity for BRD4(1)L94C over all other proteins. This work provides a proof-of-concept that the combination of site-directed mutagenesis and electrophilic fragments, in a mutate and conjugate approach, can enable rapid identification of small molecule inhibitors for an appropriately mutated protein of interest. This technology can be used to assess the cellular phenotype of inhibiting the protein of interest, and the electrophilic ligand provides a starting point for noncovalent ligand development.

Does lower extremity fracture fixation technique influence neurologic outcomes in patients with traumatic brain injury? The EAST Brain vs. Bone multicenter trial

OBJECTIVE

This study aimed to determine whether lower extremity fracture fixation technique and timing (≤24 vs. >24 hours) impact neurologic outcomes in TBI patients.

METHODS

A prospective observational study was conducted across 30 trauma centers. Inclusion criteria were age 18 years and older, head Abbreviated Injury Scale (AIS) score of >2, and a diaphyseal femur or tibia fracture requiring external fixation (Ex-Fix), intramedullary nailing (IMN), or open reduction and internal fixation (ORIF). The analysis was conducted using analysis of variamce, Kruskal-Wallis, and multivariable regression models. Neurologic outcomes were measured by discharge Ranchos Los Amigos Revised Scale (RLAS-R).

RESULTS

Of the 520 patients enrolled, 358 underwent Ex-Fix, IMN, or ORIF as definitive management. Head AIS was similar among cohorts. The Ex-Fix group experienced more severe lower extremity injuries (AIS score, 4-5) compared with the IMN group (16% vs. 3%, p = 0.01) but not the ORIF group (16% vs. 6%, p = 0.1). Time to operative intervention varied between the cohorts with the longest time to intervention for the IMN group (median hours: Ex-Fix, 15 [8-24] vs. ORIF, 26 [12-85] vs. IMN, 31 [12-70]; p < 0.001). The discharge RLAS-R score distribution was similar across the groups. After adjusting for confounders, neither method nor timing of lower extremity fixation influenced the discharge RLAS-R. Instead, increasing age and head AIS score were associated with a lower discharge RLAS-R score (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.002-1.03 and OR, 2.37; 95% CI, 1.75-3.22), and a higher Glasgow Coma Scale motor score on admission (OR, 0.84; 95% CI, 0.73-0.97) was associated with higher RLAS-R score at discharge.

CONCLUSION

Neurologic outcomes in TBI are impacted by severity of the head injury and not the fracture fixation technique or timing. Therefore, the strategy of definitive fixation of lower extremity fractures should be dictated by patient physiology and the anatomy of the injured extremity and not by the concern for worsening neurologic outcomes in TBI patients.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Outcomes Among Trauma Patients with Duodenal Leak Following Primary vs Complex Repair of Duodenal Injuries: An EAST Multicenter Trial

BACKGROUND

Duodenal leak is a feared complication of repair and innovative, complex repairs with adjunctive measures(CRAM) were developed to decrease both leak occurrence and severity when leaks occur. Data on the association of CRAM and duodenal leak is sparse and its impact on duodenal leak outcomes nonexistent. We hypothesized primary repair alone (PRA) would be associated with decreased duodenal leak rates, however CRAM would be associated with improved recovery and outcomes when leaks do occur.

METHODS

A retrospective, multicenter analysis from 35 Level-1 trauma centers included patients older than 14 with operative, traumatic duodenal injuries(1/2010-12/2020). The study sample compared duodenal operative repair strategy: primary repair alone(PRA) vs CRAM(any repair plus pyloric exclusion, gastrojejunostomy, triple tube drainage, duodenectomy).

RESULTS

The sample(n = 861) was primarily young(33 years) male(84%) with penetrating injuries(77%); 523 underwent PRA and 338 underwent CRAM. CRAM were more critically injured than PRA and had higher leak rates(CRAM 21% vs PRA 8%, p < 0.001). Adverse outcomes were more common after CRAM with more IR drains, prolonged NPO and LOS, greater mortality, and more readmissions than PRA(all p < 0.05). Importantly, CRAM had no positive impact on leak recovery; there was no difference in number of operations, drain duration, NPO duration, need for IR drainage, HLOS, or mortality between PRA leak vs CRAM leak patients(all p > 0.05). CRAM leaks had longer antibiotic duration, more GI complications, and longer duration until leak resolution(all p < 0.05). PRA was associated with 60% lower odds of leak, whereas injury grade II-IV, damage control, and BMI had higher odds of leak(all p < 0.05). There were no leaks among patients with grade IV-V injuries repaired by PRA.

CONCLUSIONS

CRAM did not prevent duodenal leaks and moreover, did not reduce adverse sequelae when leaks did occur. Our results suggest CRAM is not a protective operative duodenal repair strategy and PRA should be pursued for all injury grades when feasible.

LEVEL OF EVIDENCE

IV, Multicenter retrospective comparative study.

Risk factors for recurrence in blunt traumatic abdominal wall hernias: A secondary analysis of a Western Trauma association multicenter study

BACKGROUND

Few studies have investigated risk factors for recurrence of blunt traumatic abdominal wall hernias (TAWH).

METHODS

Twenty trauma centers identified repaired TAWH from January 2012 to December 2018. Logistic regression was used to investigate risk factors for recurrence.

RESULTS

TAWH were repaired in 175 patients with 21 (12.0%) known recurrences. No difference was found in location, defect size, or median time to repair between the recurrence and non-recurrence groups. Mesh use was not protective of recurrence. Female sex, injury severity score (ISS), emergency laparotomy (EL), and bowel resection were associated with hernia recurrence. Bowel resection remained significant in a multivariable model.

CONCLUSION

Female sex, ISS, EL, and bowel resection were identified as risk factors for hernia recurrence. Mesh use and time to repair were not associated with recurrence. Surgeons should be mindful of these risk factors but could attempt acute repair in the setting of appropriate physiologic parameters.

Identification of Histone Peptide Binding Specificity and Small-Molecule Ligands for the TRIM33α and TRIM33β Bromodomains

TRIM33 is a member of the tripartite motif (TRIM) family of proteins, some of which possess E3 ligase activity and are involved in the ubiquitin-dependent degradation of proteins. Four of the TRIM family proteins, TRIM24 (TIF1α), TRIM28 (TIF1β), TRIM33 (TIF1γ) and TRIM66, contain C-terminal plant homeodomain (PHD) and bromodomain (BRD) modules, which bind to methylated lysine (KMe_n) and acetylated lysine (KAc), respectively. Here we investigate the differences between the two isoforms of TRIM33, TRIM33α and TRIM33β, using structural and biophysical approaches. We show that the N1039 residue, which is equivalent to N140 in BRD4(1) and which is conserved in most BRDs, has a different orientation in each isoform. In TRIM33β, this residue coordinates KAc, but this is not the case in TRIM33α. Despite these differences, both isoforms show similar affinities for H3_1-27K18Ac, and bind preferentially to H3_1-27K9Me₃K18Ac. We used this information to develop an AlphaScreen assay, with which we have identified four new ligands for the TRIM33 PHD-BRD cassette. These findings provide fundamental new information regarding which histone marks are recognized by both isoforms of TRIM33 and suggest starting points for the development of chemical probes to investigate the cellular function of TRIM33.

Management of blunt traumatic abdominal wall hernias: A Western Trauma Association multicenter study

BACKGROUND

Blunt traumatic abdominal wall hernias (TAWH) occur in approximately 15,000 patients per year. Limited data are available to guide the timing of surgical intervention or the feasibility of nonoperative management.

METHODS

A retrospective study of patients presenting with blunt TAWH from January 2012 through December 2018 was conducted. Patient demographic, surgical, and outcomes data were collected from 20 institutions through the Western Trauma Association Multicenter Trials Committee.

RESULTS

Two hundred and eighty-one patients with TAWH were identified. One hundred and seventy-six (62.6%) patients underwent operative hernia repair, and 105 (37.4%) patients underwent nonoperative management. Of those undergoing surgical intervention, 157 (89.3%) were repaired during the index hospitalization, and 19 (10.7%) underwent delayed repair. Bowel injury was identified in 95 (33.8%) patients with the majority occurring with rectus and flank hernias (82.1%) as compared with lumbar hernias (15.8%). Overall hernia recurrence rate was 12.0% (n = 21). Nonoperative patients had a higher Injury Severity Score (24.4 vs. 19.4, p = 0.010), head Abbreviated Injury Scale score (1.1 vs. 0.6, p = 0.006), and mortality rate (11.4% vs. 4.0%, p = 0.031). Patients who underwent late repair had lower rates of primary fascial repair (46.4% vs. 77.1%, p = 0.012) and higher rates of mesh use (78.9% vs. 32.5%, p < 0.001). Recurrence rate was not statistically different between the late and early repair groups (15.8% vs. 11.5%, p = 0.869).

CONCLUSION

This report is the largest series and first multicenter study to investigate TAWHs. Bowel injury was identified in over 30% of TAWH cases indicating a significant need for immediate laparotomy. In other cases, operative management may be deferred in specific patients with other life-threatening injuries, or in stable patients with concern for bowel injury. Hernia recurrence was not different between the late and early repair groups.

LEVEL OF EVIDENCE

Therapeutic/care management, Level IV.

Fragment-Based Identification of Ligands for Bromodomain-Containing Factor 3 of Trypanosoma cruzi

The Trypanosoma cruzi (T. cruzi) parasite is the cause of Chagas disease, a neglected disease endemic in South America. The life cycle of the T. cruzi parasite is complex and includes transitions between distinct life stages. This change in phenotype (without a change in genotype) could be controlled by epigenetic regulation, and might involve the bromodomain-containing factors 1-5 (TcBDF1-5). However, little is known about the function of the TcBDF1-5. Here we describe a fragment-based approach to identify ligands for T. cruzi bromodomain-containing factor 3 (TcBDF3). We expressed a soluble construct of TcBDF3 in E. coli, and used this to develop a range of biophysical assays for this protein. Fragment screening identified 12 compounds that bind to the TcBDF3 bromodomain. On the basis of this screen, we developed functional ligands containing a fluorescence or ¹⁹F reporter group, and a photo-crosslinking probe for TcBDF3. These tool compounds will be invaluable in future studies on the function of TcBDF3 and will provide insight into the biology of T. cruzi.

Outcomes after ultramassive transfusion in the modern era: An Eastern Association for the Surgery of Trauma multicenter study

BACKGROUND

Despite the widespread institution of modern massive transfusion protocols with balanced blood product ratios, survival for patients with traumatic hemorrhage receiving ultramassive transfusion (UMT) (defined as ≥20 U of packed red blood cells [RBCs]) in 24 hours) remains low and resource consumption remains high. Therefore, we aimed to identify factors associated with mortality in trauma patients receiving UMT in the modern resuscitation era.

METHODS

An Eastern Association for the Surgery of Trauma multicenter retrospective study of 461 trauma patients from 17 trauma centers who received ≥20 U of RBCs in 24 hours was performed (2014-2019). Multivariable logistic regression and Classification and Regression Tree analysis were used to identify clinical characteristics associated with mortality.

RESULTS

The 461 patients were young (median age, 35 years), male (82%), severely injured (median Injury Severity Score, 33), in shock (median shock index, 1.2; base excess, -9), and transfused a median of 29 U of RBCs, 22 U of fresh frozen plasma (FFP), and 24 U of platelets (PLT). Mortality was 46% at 24 hours and 65% at discharge. Transfusion of RBC/FFP ≥1.5:1 or RBC/PLT ≥1.5:1 was significantly associated with mortality, most pronounced for the 18% of patients who received both RBC/PLT and RBC/FFP ≥1.5:1 (odds ratios, 3.11 and 2.81 for mortality at 24 hours and discharge; both p < 0.01). Classification and Regression Tree identified that age older than 50 years, low initial Glasgow Coma Scale, thrombocytopenia, and resuscitative thoracotomy were associated with low likelihood of survival (14-26%), while absence of these factors was associated with the highest survival (71%).

CONCLUSION

Despite modern massive transfusion protocols, one half of trauma patients receiving UMT are transfused with either RBC/FFP or RBC/PLT in unbalanced ratios ≥1.5:1, with increased associated mortality. Maintaining focus on balanced ratios during UMT is critical, and consideration of advanced age, poor initial mental status, thrombocytopenia, and resuscitative thoracotomy can aid in prognostication.

LEVEL OF EVIDENCE

Prognostic, level III.

The Effect of Lung Lavage Volume Return on the Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND

Bronchoalveolar lavage (BAL) is a commonly used tool in the diagnosis of ventilator-associated pneumonia (VAP). Previous protocols recommend 30% lavage return, though no studies have investigated this relationship. This study aims to assess the influence of BAL volume return on VAP diagnosis.

MATERIALS AND METHODS

A retrospective review was performed of a prospectively maintained database for BAL performed from January 2015 to January 2016 in the trauma and surgical ICU at a level 1 trauma center. In total, 147 ventilated patients with clinical suspicion for pneumonia underwent 264 BALs. A protocol was used with five aliquots of 20 cc of saline instilled. Quantitative cultures were performed with 10ˆ5 colony-forming organisms as the threshold for VAP diagnosis. BAL was repeated at 6-8 d on 50 patients. Univariate and multivariate regression analyses were performed to investigate the predictors of VAP diagnosis.

RESULTS

Patients with >40% lavage return had increased rates of VAP diagnosis (odds ratio [OR] 2.86, P = 0.002). Increasing volume return also trended toward a lower false-negative rate. Temperature, leukocytosis, and X-ray infiltrate were not associated with increased VAP diagnosis. Concurrent antibiotic therapy at the time of BAL predicted decreased VAP diagnosis (OR 0.58, P = 0.04). On multivariable analysis, only >40% return remained associated with increased rate of VAP diagnosis (OR 4.00, P = 0.004).

CONCLUSIONS

This study found that >40% lavage volume return was associated with increased VAP diagnosis. Clinicians should consider the reliability of a negative BAL if clinical suspicion of VAP is high and lavage return is <40%. Additional investigation is needed to further elucidate this association.

Characterisation of utrophin modulator SMT C1100 as a non-competitive inhibitor of firefly luciferase

Firefly luciferase (FLuc) is a powerful tool for molecular and cellular biology, and popular in high-throughput screening and drug discovery. However, FLuc assays have been plagued with positive and negative artefacts due to stabilisation and inhibition by small molecules from a range of chemical classes. Here we disclose Phase II clinical compound SMT C1100 for the treatment of Duchenne muscular dystrophy as an FLuc inhibitor (K_D of 0.40 ± 0.15 µM). Enzyme kinetic studies using SMT C1100 and other non-competitive inhibitors including resveratrol and NFκBAI4 identified previously undescribed modes of inhibition with respect to FLuc's luciferyl adenylate intermediate. Employing a photoaffinity strategy to identify SMT C1100's binding site, a photolabelled SMT C1100 probe instead underwent FLuc-dependent photooxidation. Our findings support novel binding sites on FLuc for non-competitive inhibitors.

BET bromodomain ligands: Probing the WPF shelf to improve BRD4 bromodomain affinity and metabolic stability

Ligands for the bromodomain and extra-terminal domain (BET) family of bromodomains have shown promise as useful therapeutic agents for treating a range of cancers and inflammation. Here we report that our previously developed 3,5-dimethylisoxazole-based BET bromodomain ligand (OXFBD02) inhibits interactions of BRD4(1) with the RelA subunit of NF-κB, in addition to histone H4. This ligand shows a promising profile in a screen of the NCI-60 panel but was rapidly metabolised (t½ = 39.8 min). Structure-guided optimisation of compound properties led to the development of the 3-pyridyl-derived OXFBD04. Molecular dynamics simulations assisted our understanding of the role played by an internal hydrogen bond in altering the affinity of this series of molecules for BRD4(1). OXFBD04 shows improved BRD4(1) affinity (IC50 = 166 nM), optimised physicochemical properties (LE = 0.43; LLE = 5.74; SFI = 5.96), and greater metabolic stability (t½ = 388 min).

Multicenter comparison of the high volume (10 ml) NR BACTEC PLUS system and the standard (5 ml) NR BACTEC system

This multicenter study was designed to compare the new BACTEC PLUS system (nonradiometric), which utilizes an 8- to 10-ml blood inoculum in a resin-containing medium, to the standard BACTEC (nonradiometric) without resins and 5-ml blood inoculum. There were 12,341 compliant sets studied, yielding 1331 positives, with 1099 sets deemed clinically significant. Overall the BACTEC PLUS showed an enhanced recovery of 33% (p less than 0.001) over its standard counterpart, with significant yield increased in the staphylococci (p less than 0.001), streptococci (p less than 0.002), pseudomonads (p less than 0.002), Enterobacteriaceae (p less than 0.001), and other aerobic Gram negatives (p less than 0.02). The enhanced performance increased to 53% if the patient was receiving any antibiotics at the time the blood was cultured. In patients known to be free of antibiotics at the time of blood draw, there was still an increased yield of 18%. The new system detected positivity at least one reading sooner than twice as often as the converse, and confirmed septic episodes significantly more often (21% overall) (41% on antibiotics) (15% no antibiotics). The BACTEC PLUS has distinct advantages over its low blood volume, nonresin counterpart.

Volume of blood submitted for culture from neonates

We prospectively examined 298 sets (298 aerobic, 299 anaerobic, and 73 resin cultures) of blood cultures from 161 critically ill newborns. The attending physicians were unaware of the study. The mean blood volume per patient (aerobic and anaerobic) was 1.05 (range, 0.11 to 3.04) ml. The mean blood volume per aerobic bottle was 0.53 (range, 0.01 to 1.90) ml. Among aerobic samples 2.7% were less than or equal to 0.1 ml, 16% were less than or equal to 0.3 ml, 33% were less than or equal to 0.4 ml, and 55% were less than or equal to 0.5 ml. For anaerobic cultures the mean blood volume was 0.52 (range, 0.01 to 1.79) ml. Among anaerobic samples 2.7% were less than or equal to 0.1 ml, 15% were less than or equal to 0.3 ml, 35% were less than or equal to 0.4 ml, and 58% were less than or equal to 0.5 ml. Blood volume did not correlate with gestational age, chronologic age, or weight. The mean volume of blood submitted in positive cultures was not significantly greater than that in negative cultures. The blood volume used for culture from ill newborns may be inadequate for detecting sepsis, and the adequacy of currently available culture methods needs to be assessed for the small samples submitted from critically ill newborns.

Pasteurella multocida meningitis in infancy. An avoidable infection

Pasteurella multocida is a common commensal in the upper respiratory tracts of cats and dogs. Infection with P multocida in humans usually follows infected bite wounds; however, infection in humans unrelated to animal bites is rare. We describe two infants with P multocida meningitis in whom infection was probably related to nontraumatic facial licking by household pet dogs. Both patients recovered fully. Although the risk is low, parents should be informed that mucous membrane exposure to household pets may expose an infant to the risk of systemic P multocida infection.