Composition of Challenge Substance in Standardized Antimicrobial Efficacy Testing of Wound Antimicrobials Is Essential to Correctly Simulate Efficacy in the Human Wound Micro-Environment

Current standards insufficiently acknowledge the influence of the wound micro-environment on the efficacy of antimicrobial agents. To address this, octenidine/phenoxyethanol, polyhexanide, povidone-iodine, and sodium-hypochloride/hypochlorous acid solutions were submitted to standard-based (DIN-EN-13727) or modified peptide-based challenges and compared to a simulated clinical reference using human acute or chronic wound exudate (AWF/CWF). Antimicrobial efficacy against S. aureus and P. aeruginosa was compared using a quantitative suspension method. Agreement between methods were investigated using Bland-Altman (B&A) analysis. Different substances and challenges demonstrated diverging results, depending on class and concentration of agent and challenge. Highly concentrated antiseptics maintained a high efficacy under complex challenges, while especially chlorine-based irrigation solutions showed a remarkably reduced antimicrobial effect. Composition of challenge substance proved more relevant than pure concentration. Therefore, the current standard challenge conditions did not adequately reflect the wound micro-environment with over- or under-estimating antimicrobial efficacy, whilst the modified peptide-challenge showed a higher level of agreement with simulated realistic conditions (AWF/CWF). The results emphasize that a “one-fits-all” approach is not feasible to generalize antimicrobial efficacy, as certain aspects of the complex micro-environment pose a differing influence on varying agents. Based on these results, revision and target focused adaptation of the current standards should be considered

The role of saline irrigation prior to wound closure in the reduction of surgical site infection: a systematic review and meta-analysis

Background!#!Surgical site infection (SSI) describes an infectious complication of surgical wounds. Although SSI is thought to be preventable, it still represents a major cause of morbidity and substantial economic burden on the health system. Wound irrigation (WI) might reduce the level of bacterial contamination, but current data on its role in reducing or preventing SSI is conflicting. Our aim was to investigate the effectiveness of WI with normal saline prior to wound closure for the reduction of SSI in patients undergoing abdominal surgery.!##!Methods!#!We conducted a systematic literature search in MEDLINE, EMBASE, and CENTRAL from inception to present, and cross-checked the reference lists of all included primary studies and relevant systematic reviews. (Quasi-) randomized controlled trials (RCTs) investigating the rate of SSI when using normal saline vs. no irrigation prior to wound closure following abdominal surgery were included. Primary outcome was the rate of SSI, secondary outcome the mean length of hospital stay (LOS).!##!Results!#!Four RCTs including a total of 1194 patients were included for analysis. All studies compared wound irrigation with normal saline with no wound irrigation prior to wound closure. Their risk of bias was moderate. The relative risk of developing a SSI was lower when wound irrigation with normal saline was performed prior to wound closure although the effect was not statistically significant (risk ratio 0.73, 95%-confidence level: 0.37 to 1.43). Similarly, there was no difference in the LOS amongst both intervention arms.!##!Conclusion!#!This systematic review could not identify an advantage for routine irrigation of abdominal wounds with normal saline over no irrigation prior to wound closure in preventing or reducing the rate of SSI.!##!Systematic review registration!#!PROSPERO registry number CRD42018082287

The role of saline irrigation prior to wound closure in the reduction of surgical site infection: protocol for a systematic review and meta-analysis

Abstract Background Surgical site infection describes an infectious complication of surgical wounds. This single complication is thought to occur in close to 20% of surgical cases. This complication has been described in all kinds of surgical procedure including minimally invasive procedures. Wound irrigation is frequently used as a means of reducing surgical site infection. However, there is lack of solid evidence to support routine wound irrigation. The aim of this review is to provide evidence for the efficacy of routine wound irrigation with normal saline in preventing surgical site infection. The rate of surgical site infection in cases with and without wound irrigation will be analyzed. Methods/design Systematic literature searches will be conducted to identify all published and unpublished studies. The following databases will be searched for citations from inception to present: MEDLINE (via PubMed), Embase (via Embase), and CENTRAL (via the Cochrane library). The search strategy will be developed by the research team in collaboration with an experienced librarian and checked by a referee according to the Peer Review of Electronic Search Strategies (PRESS) guideline. A draft of the PubMed search strategy could be (irrigation[tiab] OR “Therapeutic Irrigation”[mesh] OR lavage[tiab]) AND (saline[tiab] OR “Sodium Chloride”[mesh] OR sodium chloride[tiab]) NOT (“Comment” [Publication Type] OR “Letter” [Publication Type] OR “Editorial” [Publication Type]). No time limits will be set. The reference lists of eligible articles will be hand searched. Relevant data will be extracted from eligible studies using a previously designed data extraction sheet. Relative risks will be calculated for binary outcomes and mean differences or standardized mean differences, if necessary, for continuous outcomes. For all measures, 95% confidence levels will be calculated. Both arms would be compared with regard to the rate of surgical site infection within 30 days following surgery. We will report the review using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Discussion This review aims at investigating the value of routine wound irrigation using normal saline in preventing surgical site infection. Systematic review registration PROSPERO: CRD4201808228

The Comparison of Endovascular and Open Surgical Treatment for Ruptured Abdominal Aortic Aneurysm in Terms of Safety and Efficacy on the Basis of a Single-Center 30-Year Experience

Objective: Ruptured abdominal aortic aneurysm (rAAA) is a critical condition with a high mortality rate. Over the years, endovascular aortic repair (EVAR) has evolved as a viable treatment option in addition to open repair (OR). The primary objective of this study was to compare the safety and efficacy of EVAR and OR for the treatment of rAAA based on a comprehensive analysis of our single-centre 30-year experience. Methods: Patients treated for rAAA at the Department of Vascular and Endovascular Surgery, University Hospital Düsseldorf, Germany from 1 January 1993 to 31 December 2022 were included. Relevant information was retrieved from archived medical records. Patient survival and surgery-related complications were analysed. Results: None of the patient-specific markers, emergency department-associated parameters, and co-morbidities were associated with patient survival. The 30-day and in-hospital mortality was higher in the OR group vs. in the EVAR group (50% vs. 8.7% and 57.1% vs. 13%, respectively). OR was associated with more frequent occurrence of more severe complications when compared to EVAR. Overall patient survival was 56 ± 5% at 12 months post-surgery (52 ± 6% for OR vs. 73 ± 11% for EVAR, respectively) (p p < 0.05). In the EVAR group, this age-related survival advantage was not found (12-month survival: ≥70 years: 67 ± 14%, <70 years: 86 ± 13%). Gender-specific survival was similar regardless of the applied method of care. Conclusion: OR was associated with more severe complications in our study. EVAR initially outperformed OR for rAAA regarding patient survival while re-interventions following EVAR negatively affect survival in the long-term. Elderly patients should be treated with EVAR. Gender does not seem to have a significant impact on survival

Comparison of hemostatic dressings for superficial wounds using a new spectrophotometric coagulation assay

Background: Due to demographical changes the number of elderly patients depending on oral anticoagulation is expected to rise. Prolonged bleeding times in case of traumatic injuries represent the drawback of these medications, not only in major trauma, but also in superficial wounds. Therefore, dressings capable of accelerating coagulation onset and shortening bleeding times are desirable for these patients. Methods: The hemostatic potential and physical properties of different types of superficial wound dressings (standard wound pad, two alginates, chitosan, collagen (Lyostypt (R)), oxidized cellulose, and QuikClot (R)) were assessed in vitro. For this purpose the clotting times of blood under the influence of the named hemostatics from healthy volunteers were compared with Marcumar (R) or ASS (R) treated patients. For that, a newly developed coagulation assay based on spectrophotometric extinction measurements of thrombin activity was used. Results: The fastest coagulation onset was observed for oxidized cellulos (empty set 2.47 min), Lantor alginate-L (empty set 2.50 min) and QuikClot (R) (empty set 3.01 min). Chitosan (empty set 5.32 min) and the collagen Lyostypt (R) (empty set 7.59 min) induced clotting comparatively late. Regarding physical parameters, QuikClot (R) showed the lowest absorption capacity and speed while chitosan and both alginates achieved the highest. While oxidized cellulose displayed the best clotting times, unfortunately it also revealed low absorption capacity. Conclusions: All tested specimens seem to induce clotting independently from the administered type of oral anticoagulant, providing the possibility to neglect the disadvantage in clotting times arising from anticoagulation on a local basis. QuikClot (R), oxidized cellulose and unexpectedly alginate-L were superior to chitosan and Lyostypt (R). Due to its additional well-known positive effect on wound healing alginate-L should be considered for further investigations

Effect of Gelatin-Based Hemostats on Fibroblasts and Relevant Growth Factors in Wound Healing

Gelatin-based hemostats have been used in various surgical fields and showed advantageous effects on central aspects of wound healing when compared to cellulose-based hemostats. Nevertheless, the influence of gelatin-based hemostats on wound healing has not been fully explored yet. Hemostats were applied to fibroblast cell cultures for 5, 30, 60 min, 24 h, 7 and 14 days and measurements were taken at 3, 6, 12, 24 h and 7 or 14 days, respectively. Cell proliferation was quantified after different exposure times and a contraction assay was conducted to measure the extent of the extracellular matrix over time. We further assessed quantitative levels of vascular endothelial growth factor and basic fibroblast growth factor using enzyme-linked immunosorbent assay. Fibroblast counts decreased significantly at 7 and 14 days independent of the application duration (p p < 0.05). Gelatin-based hemostats did not impair contraction of the extracellular matrix or growth factor production (vascular endothelial growth factor and basic fibroblast growth factor), while cell proliferation diminished at late time points. In conclusion, the gelatin-based material seems to be compatible with central aspects of wound healing. For further clinical assessment, future animal and human studies are necessary

The Role of Spatial Aortic Arch Architecture in Type B Aortic Dissection

Objective: The incidence of type B aortic dissection (TBAD) is increasing worldwide; however, the underlying pathomechanisms are not conclusively understood. This study explores the geometric architecture of the aortic arch and supra-aortic branches in TBAD patients as opposed to non-TBAD patients. Methods: Patient characteristics were retrieved from archived medical records. Computer-assisted tomography (CAT) scans of patients with TBAD and carotid stenosis (CS) from two high-volume centers were analyzed. Various aortic arch parameters and take-off angles of the supra-aortic branches of TBAD patients were measured following centerline normalization in comparison CS patients. A compression index (C-index) was calculated from the para-sagittal, and a torsion index (T-index) was calculated from the para-coronal take-off angles of the supra-aortic branches to analyze aortic arch tortuosity. Results: A total of 199 CAT scans were analyzed, namely, 85 in the TBAD group and 114 in the CS group. The average age was 61.5 ± 13.1 years among the TBAD patients and 71 ± 9.3 years among the CS patients. We found a significantly higher proportion of type III aortic arch configurations in TBAD patients compared with CS patients. Further, the aortic arch angle was steeper in the TBAD group. In the para-sagittal plane, the left subclavian artery (LSA) take-off angle was less steep in TBAD patients. In the para-coronal plane, the left carotid artery (LCA) had a less steep take-off angle, while the LSA had a more obtuse take-off angle in the TBAD group when compared with the CS group. In addition, the inter-vessel distance was increased in TBAD patients. Finally, the T-index was increased, suggesting a significant torsion resulting from the deviating take-off angles of the supra-aortic branches supplying the left half of the body as opposed to the innominate artery (IA) in TBAD patients. Conclusions: Our results suggest several aortic arch-specific geometric configurations in patients suffering from TBAD that significantly differ from those in CS patients. Further functional studies are needed to verify the pathogenetic relevance of our results and their disease-specific causality. Although our data are not mechanistically explorative, they may serve as a basis for identifying future patients with aortic arch morphology at higher risk for TBAD development and who may benefit from more stringent adjustment of risk factors as a primary prevention concept