Prediction of anastomotic insufficiency based on the mucosal microbiome prior to colorectal surgery: a proof-of-principle study.

Anastomotic leakage (AL) is a potentially life-threatening complication following colorectal cancer (CRC) resection. In this study, we aimed to unravel longitudinal changes in microbial structure before, during, and after surgery and to determine if microbial alterations may be predictive for risk assessment between sufficient anastomotic healing (AS) and AL prior surgery. We analysed the microbiota of 134 colon mucosal biopsies with 16S rRNA V1-V2 gene sequencing. Samples were collected from three location sites before, during, and after surgery, and patients received antibiotics after the initial collection and during surgery. The microbial structure showed dynamic surgery-related changes at different time points. Overall bacterial diversity and the abundance of some genera such as Faecalibacterium or Alistipes decreased over time, while the genera Enterococcus and Escherichia_Shigella increased. The distribution of taxa between AS and AL revealed significant differences in the abundance of genera such as Prevotella, Faecalibacterium and Phocaeicola. In addition to Phocaeicola, Ruminococcus2 and Blautia showed significant differences in abundance between preoperative sample types. ROC analysis of the predictive value of these genera for AL revealed an AUC of 0.802 (p = 0.0013). In summary, microbial composition was associated with postoperative outcomes, and the abundance of certain genera may be predictive of postoperative complications.

Surgical Revision Promotes Presence of Enterococcus spp. in Abdominal Superficial Surgical Site Infections.

BACKGROUND: Superficial surgical site infections (SSSIs) are a major reason for morbidity after abdominal surgery. Microbiologic isolates of SSSIs vary widely geographically. Therefore, knowledge about the specific bacterial profile is of paramount importance to prevent SSSI. METHODS: We performed a subgroup analysis of the microbiological isolates from patients with SSSI after abdominal surgery that were included in our institutional wound register. We aimed at identifying predominant strains as well as risk factors that would predispose for SSSI with certain bacteria. RESULTS: A total of 494 patients were eligible for analysis. Of those 313 had received wound swaps, with 268 patients yielding a bacterial isolate. Enterobacterales (31.7%) and Enterococcus spp. (29.5%) were found as main bacteria in SSSI, with 62.3% of the wounds being polymicrobial. As risk factors for changes in bacterial isolates, we identified operative revision (OR 3.032; 95%CI 1.734-5.303) in multivariate analysis. Enterococcus spp. showed a significant increase in patients after revision surgery (p<0.001). Antibiotic therapy was neither influential on bacterial changes nor on the presence of Enterococcus spp. in SSSI. CONCLUSION: Our study accentuates the high frequency of Enterococcus spp. in SSSI after abdominal surgery, while identifying surgical revision as major risk factor. The results urge vigilance in the treatment of patients with surgical revisions to include Enterococcus spp. in the prevention and treatment strategies.

Hyperspectral Imaging (HSI)-A New Tool to Estimate the Perfusion of Upper Abdominal Organs during Pancreatoduodenectomy.

Hyperspectral imaging (HSI) in abdominal surgery is a new non-invasive tool for the assessment of the perfusion and oxygenation of various tissues and organs. Its benefit in pancreatic surgery is still unknown. The aim of this study was to evaluate the key impact of using HSI during pancreatoduodenectomy (PD). In total, 20 consecutive patients were included. HSI was recorded during surgery as part of a pilot study approved by the local Ethics Committee. Data were collected prospectively with the TIVITA® Tissue System. Intraoperative HS images were recorded before and after gastroduodenal artery (GDA) clamping. We detected four patients with celiac artery stenosis (CAS) caused by a median arcuate ligament (MAL). In two of these patients, a reduction in liver oxygenation (StO2) was discovered 15 and 30 min after GDA clamping. The MAL was divided in these patients. HSI showed an improvement of liver StO2 after MAL division (from 61% to 73%) in one of these two patients. There was no obvious decrease in liver StO2 in the other two patients with CAS. HSI, as a non-invasive procedure, could be helpful in evaluating liver and gastric perfusion during PD, which might assist surgeons in choosing the best surgical approach and in improving patients' outcomes.

Mechanical Ventilation Strategies Targeting Different Magnitudes of Collapse and Tidal Recruitment in Porcine Acid Aspiration-Induced Lung Injury.

Reducing ventilator-associated lung injury by individualized mechanical ventilation (MV) in patients with Acute Respiratory Distress Syndrome (ARDS) remains a matter of research. We randomly assigned 27 pigs with acid aspiration-induced ARDS to three different MV protocols for 24 h, targeting different magnitudes of collapse and tidal recruitment (collapse&TR): the ARDS-network (ARDSnet) group with low positive end-expiratory pressure (PEEP) protocol (permissive collapse&TR); the Open Lung Concept (OLC) group, PaO2/FiO2 >400 mmHg, indicating collapse&TR <10%; and the minimized collapse&TR monitored by Electrical Impedance Tomography (EIT) group, standard deviation of regional ventilation delay, SDRVD. We analyzed cardiorespiratory parameters, computed tomography (CT), EIT, and post-mortem histology. Mean PEEP over post-randomization measurements was significantly lower in the ARDSnet group at 6.8 ± 1.0 cmH2O compared to the EIT (21.1 ± 2.6 cmH2O) and OLC (18.7 ± 3.2 cmH2O) groups (general linear model (GLM) p < 0.001). Collapse&TR and SDRVD, averaged over all post-randomization measurements, were significantly lower in the EIT and OLC groups than in the ARDSnet group (collapse p < 0.001, TR p = 0.006, SDRVD p < 0.004). Global histological diffuse alveolar damage (DAD) scores in the ARDSnet group (10.1 ± 4.3) exceeded those in the EIT (8.4 ± 3.7) and OLC groups (6.3 ± 3.3) (p = 0.16). Sub-scores for edema and inflammation differed significantly (ANOVA p < 0.05). In a clinically realistic model of early ARDS with recruitable and nonrecruitable collapse, mechanical ventilation involving recruitment and high-PEEP reduced collapse&TR and resulted in improved hemodynamic and physiological conditions with a tendency to reduced histologic lung damage.