Is early detection of anastomotic leakage possible by intraperitoneal microdialysis and intraperitoneal cytokines after anterior resection of the rectum for cancer?

Peritoneal fluid indocyanine green test for diagnosis of gut leakage in anastomotic leakage rats and colorectal surgery patients

BACKGROUND

Application of indocyanine green (ICG) fluorescence has led to new developments in gastrointestinal surgery. However, little is known about the use of ICG for the diagnosis of postoperative gut leakage (GL). In addition, there is a lack of rapid and intuitive methods to definitively diagnose postoperative GL.

AIM

To investigate the effect of ICG in the diagnosis of anastomotic leakage in a surgical rat GL model and evaluate its diagnostic value in colorectal surgery patients.

METHODS

Sixteen rats were divided into two groups: GL group (n = 8) and sham group (n = 8). Approximately 0.5 mL of ICG (2.5 mg/mL) was intravenously injected postoperatively. The peritoneal fluid was collected for the fluorescence test at 24 and 48 h. Six patients with rectal cancer who had undergone laparoscopic rectal cancer resection plus enterostomies were injected with 10 mL of ICG (2.5 mg/mL) on postoperative day 1. Their ostomy fluids were collected 24 h after ICG injection to identify the possibility of the ICG excreting from the peripheral veins to the enterostomy stoma. Participants who had undergone colectomy or rectal cancer resection were enrolled in the diagnostic test. The peritoneal fluids from drainage were collected 24 h after ICG injection. The ICG fluorescence test was conducted using OptoMedic endoscopy along with a near-infrared fluorescent imaging system.

RESULTS

The peritoneal fluids from the GL group showed ICG-dependent green fluorescence in contrast to the sham group. Six samples of ostomy fluids showed green fluorescence, indicating the possibility of ICG excreting from the peripheral veins to the enterostomy stoma in patients. The peritoneal fluid ICG test exhibited a sensitivity of 100% and a specificity of 83.3% for the diagnosis of GL. The positive predictive value was 71.4%, while the negative predictive value was 100%. The likelihood ratios were 6.0 for a positive test result and 0 for a negative result.

CONCLUSION

The postoperative ICG test in a drainage tube is a valuable and simple technique for the diagnosis of GL. Hence, it should be employed in clinical settings in patients with suspected GL.

Inflammatory biomarker signatures in post-surgical drain fluid may detect anastomotic leaks within 48 hours of colorectal resection

BACKGROUND

The optimal treatment of colorectal cancer is surgical resection and primary anastomosis. Anastomotic leak can affect up to 20% of patients and creates significant morbidity and mortality. Current diagnosis of a leak is based on clinical suspicion and subsequent radiology. Peritoneal biomarkers have shown diagnostic utility in other conditions and could be useful in providing earlier diagnosis. This pilot study was designed to assess the practical utility of peritoneal biomarkers after abdominal surgery utilising an automated immunoassay system in routine use for quantifying cytokines.

METHODS

Patients undergoing an anterior resection for a rectal cancer diagnosis were recruited at University Hospital of Wales, Cardiff between June 2019 and June 2021. A peritoneal drain was placed in the proximity of the anastomosis during surgery, and peritoneal fluid was collected at days 1 to 3 post-operatively, and analysed using the Siemens IMMULITE platform for interleukin (IL)-1β, IL-6, IL-10, CXCL8, tumour necrosis factor alpha (TNFα) and C-reactive protein (CRP).

RESULTS

A total of 42 patients were recruited (22M:20F, median age 65). Anastomotic leak was detected in four patients and a further five patients had other intra-abdominal complications. The IMMULITE platform was able to provide robust and reliable results from the analysis of the peritoneal fluid. A metric based on the combination of peritoneal IL-6 and CRP levels was able to accurately diagnose three anastomotic leaks, whilst correctly classifying all negative control patients including those with other complications.

CONCLUSIONS

This pilot study demonstrates that a simple immune signature in surgical drain fluid could accurately diagnose an anastomotic leak at 48 h postoperatively using instrumentation that is already widely available in hospital clinical laboratories.

Peritoneal and Systemic Interleukin-10 as Early Biomarkers for Colorectal Anastomotic Leakage Following Surgery in Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

<b><br>Introduction:</b> Despite advancements in diagnostic methods, the early detection of colorectal anastomotic leakage (CAL) continues to pose challenges. The identification of reliable markers is crucial to reduce patient morbidity and mortality. Cytokines present in drain fluid and systemic cytokine levels have shown promise as predictive markers for CAL; however, additional high-quality evidence is warranted to enhance the reliability and validity of the findings in this field.</br> <b><br>Aim:</b> This systematic review and meta-analysis aimed to assess the significance of peritoneal and serum/plasma interleukin-10 (IL-10) levels in the early detection of CAL in patients undergoing colorectal surgery for colorectal cancer.</br> <b><br>Methods:</b> A comprehensive literature search was conducted in PubMed, Scopus, and Web of Science databases, covering studies published until July 2023. The search aimed to identify relevant studies investigating the levels of plasma/serum and peritoneal IL-10 (or both) in colorectal cancer patients undergoing colorectal surgery, specifically focusing on the presence of CAL. Data on the mean and standard deviation of IL-10 levels in both CAL and non-CAL patients were extracted from the selected studies. Mean differences in IL-10 levels were analyzed for each postoperative day (POD) using the OpenMeta [analyst] software.</br> <b><br>Results:</b> 11 articles were selected for inclusion in this systematic review. Among them, nine articles reported data on peritoneal IL-10 levels, while four articles focused on circulating IL-10 levels. The statistical analysis included four eligible articles that assessed peritoneal IL-10 levels, and the results indicated no significant increase in CAL patients compared to non-CAL patients on any postoperative day (POD). Meta-analysis for circulating IL-10 levels was not feasible.</br> <b><br>Conclusions:</b> Up to now, peritoneal and systemic IL-10 levels cannot be considered as early markers for CAL after colorectal surgery in colorectal cancer patients. More high-quality studies are needed to establish the potential of IL-10 as a reliable marker for detecting anastomotic leakage after colorectal surgery.</br>.

Surface microdialysis measures local tissue metabolism after Ivor Lewis esophagectomy; an attempt to predict anastomotic defect

Anastomotic defect (AD) after esophagectomy can lead to severe complications with need for surgical or endoscopic intervention. Early detection enables early treatment and can limit the consequences of the AD. As of today, there are limited methods to predict AD. In this study, we have used microdialysis (MD) to measure local metabolism at the intrathoracic anastomosis. Feasibility and possible diagnostic use were investigated. Sixty patients planned for Ivor Lewis esophagectomy were enrolled. After construction of the anastomosis, surface MD (S-MD) probes were attached to the outer surface of the esophageal remnant and the gastric conduit in close vicinity of the anastomosis and left in place for 7 postoperative days (PODs). Continuous sampling of local tissue concentrations of metabolic substances (glucose, lactate, and pyruvate) was performed postoperatively. Outcome, defined as AD or not according to Esophagectomy Complications Consensus Group definitions, was recorded at discharge or at first postoperative follow up. Difference in concentrations of metabolic substances was analyzed retrospectively between the two groups by means of artificial neural network technique. S-MD probes can be attached and removed from the gastric tube reconstruction without any adverse events. Deviating metabolite concentrations on POD 1 were associated with later development of AD. In subjects who developed AD, no difference in metabolic concentrations between the esophageal and the gastric probe was recorded. The technical failure rate of the MD probes/procedure was high. S-MD can be used in a clinical setting after Ivor Lewis esophagectomy. Deviation in local tissue metabolism on POD 1 seems to be associated with development of AD. Further development of MD probes and procedure is required to reduce technical failure.

A novel nomogram for anastomotic leakage after surgery for rectal cancer: a retrospective study

Background

Anastomotic leakage remains one of the most common serious complications after rectal cancer surgery. How to predict its occurrence and prevent it remains largely elusive.

Objective

This study aimed to identify the risk factors of anastomotic leakage and construct a nomogram for predicting postoperative anastomotic leakage in patients with rectal cancer.

Methods

The data of 406 patients with rectal cancer after gastrointestinal surgery in the Third Affiliated Hospital of Sun Yat-sen University from January 2011 to May 2020 were collected (243 in the training set and 163 in the testing set). Logistic regression was applied to determine the risk factors of postoperative anastomotic leakage of rectal cancer, and a nomogram prediction model was thus established. Predictive performance of the nomogram was evaluated by C-index and area under the receiver-operating characteristic (ROC) curve.

Results

Logistic regression analysis showed that preoperative bowel obstruction (odds ratio [OR] = 12.846, 95% confidence interval CI [1.441-114.54], p = 0.022) and early first defecation after surgery (OR = 0.501, 95% CI [0.31-0.812], p = 0.005) were independent risk factors, which could be used to develop a nomogram to predict the occurrence of anastomotic leakage accurately. The evaluation of the prediction model shows that the C-index value of the model was 0.955, the area under the ROC curve (AUC) of the training set was 0.820, and the testing set was 0.747, whereas the optimal cut-off point based on the nomogram score was 174.6.

Conclusion

This nomogram had a good prediction ability for postoperative anastomotic leakage in patients with rectal cancer. It can provide a reference for perioperative treatment and the selection of surgical methods to promote individualized and accurate treatment.

Early detection of anastomotic leakage after pancreatoduodenectomy with microdialysis catheters: an observational Study

BACKGROUND

Microdialysis catheters can detect focal inflammation and ischemia, and thereby have a potential for early detection of anastomotic leakages after pancreatoduodenectomy. The aim was to investigate whether microdialysis catheters placed near the pancreaticojejunostomy can detect leakage earlier than the current standard of care.

METHODS

Thirty-five patients with a median age 69 years were included. Two microdialysis catheters were placed at the end of surgery; one at the pancreaticojejunostomy, and one at the hepaticojejunostomy. Concentrations of glucose, lactate, pyruvate, and glycerol were analyzed hourly in the microdialysate during the first 24 h, and every 2-4 h thereafter.

RESULTS

Seven patients with postoperative pancreatic fistulae (POPF) had significantly higher glycerol levels (P < 0.01) in the microdialysate already in the first postoperative samples. Glycerol concentrations >400 μmol/L during the first 12 postoperative hours detected patients with POPF with a sensitivity of 100% and a specificity of 93% (P < 0.001). After 24 h, lactate and lactate-to-pyruvate ratio were significantly higher (P < 0.05) and glucose was significantly lower (P < 0.05) in patients with POPF.

CONCLUSION

High levels of glycerol in microdialysate was an early detector of POPF. The subsequent inflammation was detected as increase in lactate and lactate-to-pyruvate ratio and a decrease in glucose (NCT03627559).

Fully covered self‐expandable metal stent placed over a stapled colon anastomosis in an animal model: A pilot study of colon metabolism over the stent

Background and Aim

Anastomotic leakage (AL) in colorectal resection and primary anastomosis is a common and feared complication. Fully covered self‐expandable metal stents (FCSEMSs) have been used for the treatment of AL. It is still unknown whether FCSEMSs affect anastomosis healing negatively by causing ischemia. In an animal study, we investigated the metabolic effects over a FCSEMS covering a stapled colon anastomosis.

Methods

Seven pigs were investigated using microdialysis after laparotomy, colon resection, and anastomosis with stent placement. Measurements were done at the proximal and distal ends of the anastomosis and at a reference catheter placed at the small intestine. Measurements of glucose, pyruvate, lactate, glycerol, and the lactate/pyruvate ratio (L/P) were carried out.

Results

Lactate and L/P were significantly higher at the oral part of the anastomosis, while glucose showed a small declining tendency. At the distal part of the anastomosis, glucose decreased significantly after the resection but did not reach zero. Lactate increased significantly whereas L/P increased only slightly. Glycerol levels were stable.

Conclusion

Colon resection caused initially hypermetabolism in the intestinal ends next to the resection site. This hypermetabolism neither deteriorated nor turned into ischemia during the initial postoperative course, but the start of hypoxemia could not be excluded during the study and after the placement of an FCSEMS.

Integrated Single-cell and Plasma Proteomic Modeling to Predict Surgical Site Complications: A Prospective Cohort Study

OBJECTIVE

The aim of this study was to determine whether single-cell and plasma proteomic elements of the host's immune response to surgery accurately identify patients who develop a surgical site complication (SSC) after major abdominal surgery.

SUMMARY BACKGROUND DATA

SSCs may occur in up to 25% of patients undergoing bowel resection, resulting in significant morbidity and economic burden. However, the accurate prediction of SSCs remains clinically challenging. Leveraging high-content proteomic technologies to comprehensively profile patients' immune response to surgery is a promising approach to identify predictive biological factors of SSCs.

METHODS

Forty-one patients undergoing non-cancer bowel resection were prospectively enrolled. Blood samples collected before surgery and on postoperative day one (POD1) were analyzed using a combination of single-cell mass cytometry and plasma proteomics. The primary outcome was the occurrence of an SSC, including surgical site infection, anastomotic leak, or wound dehiscence within 30 days of surgery.

RESULTS

A multiomic model integrating the single-cell and plasma proteomic data collected on POD1 accurately differentiated patients with (n = 11) and without (n = 30) an SSC [area under the curve (AUC) = 0.86]. Model features included coregulated proinflammatory (eg, IL-6- and MyD88- signaling responses in myeloid cells) and immunosuppressive (eg, JAK/STAT signaling responses in M-MDSCs and Tregs) events preceding an SSC. Importantly, analysis of the immunological data obtained before surgery also yielded a model accurately predicting SSCs (AUC = 0.82).

CONCLUSIONS

The multiomic analysis of patients' immune response after surgery and immune state before surgery revealed systemic immune signatures preceding the development of SSCs. Our results suggest that integrating immunological data in perioperative risk assessment paradigms is a plausible strategy to guide individualized clinical care.

Peritoneal Cytokines as Early Biomarkers of Colorectal Anastomotic Leakage Following Surgery for Colorectal Cancer: A Meta-Analysis

Background

Postoperative colorectal anastomotic leakage (CAL) is a devastating complication following colorectal resection. However, the diagnosis of anastomotic leakage is often delayed because the current methods of identification are unable to achieve 100% clinical sensitivity and specificity. This meta-analysis aimed to evaluate the predictive value of peritoneal fluid cytokines in the detection of CAL following colorectal surgery.

Methods

A comprehensive search was conducted on PubMed, Embase, Cochrane Library, and Web of Science before June 2021 to retrieve studies regarding peritoneal fluid cytokines as early markers of CAL. Pooled analyses of interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF) were performed. The means (MD) and standard deviations (SD) of the peritoneal fluid cytokines were extracted from the included studies. Review Manager Software 5.3 was used for data analysis.

Results

We included eight studies with 580 patients, among which 85 (14.7%) and 522 (44.5%) were evaluated as the CAL and non-CAL groups, respectively. Compared to the non-CAL group, the CAL group had significantly higher peritoneal IL-6 levels on postoperative day (POD) 1–3 (P = 0.0006, 0.0002, and 0.002, respectively) and slightly higher TNF levels on POD 4 (P = 0.0002). Peritoneal levels of IL-1β and IL-10 were not significantly different between the two groups in this study.

Conclusion

Peritoneal IL-6 levels can be a diagnostic marker for CAL following colorectal surgery, whereas the value of TNF needs further exploration in the future.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/#myprospero], PROSPERO (CRD42021274973)

Peritoneal cytokines as a predictor of colorectal anastomotic leaks on postoperative day 1: a systematic review and meta-analysis

BACKGROUND

Anastomotic leakage (AL) is a major complication of colorectal surgery resulting in morbidity, mortality and poorer quality of life. The early diagnosis of AL is challenging due to the poor positive predictive value of tests available and reliance on clinical presentation which may be delayed. The aim of this systematic review was to assess the applicability of peritoneal cytokine levels as an early predictive test of AL in postoperative colorectal cancer patients.

METHODS

A comprehensive literature search was performed from inception to January 2021, in MEDLINE and EMBASE databases using MeSH and non-MeSH terms in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies evaluating peritoneal cytokines in the context of AL were included in this review.

RESULTS

Two hundred ninety-two abstracts were screened, 30 full manuscripts evaluated, and 12 prospective studies were included. There were 8 peritoneal cytokines evaluated (interleukin [IL]-1β, IL-6, IL-8, IL-10, vascular endothelial growth factor [VEGF], tumour necrosis factor alpha [TNF alpha] and matrix metalloproteinase [MMP]2 and MMP9) between AL and non-AL groups on postoperative day 1. Those that included IL-6 (7 studies), IL-10 (4 studies), TNF alpha (6 studies) and MMP9 (2 studies) were included in the meta-analysis. IL-10 was the only cytokine in the meta-analysis that was significantly (p < 0.05) raised in drain fluid on postoperative day 1 in AL patients.

CONCLUSIONS

Peritoneal IL-10 was significantly raised on postoperative day 1 in patients who subsequently developed AL. This may be a useful early predictor of AL and aid in an earlier diagnosis for postoperative colorectal patients. The range of cytokines investigated within the literature is limited and from heterogeneous studies which suggests more research is needed.

Early Diagnosis of Anastomotic Leakage After Gastric Cancer Surgery Via Analysis of Inflammatory Factors in Abdominal Drainage

BACKGROUND

Anastomotic leakage (AL) is the most serious postoperative complication for patients with gastric cancer. We aim to develop clinically tools to detect AL in the early phase by analysis of the inflammatory factors (IFs) in abdominal drainage.

METHODS

We prospectively included 326 patients to establish two independent cohorts, and the concentration of IFs within abdominal drainage was detected. In the primary cohort, an IF-based AL prediction model was constructed using the least absolute shrinkage and selection operator (LASSO) regression. The predictive value of the model was later validated via the validation cohort.

RESULTS

Analyzing the IFs with LASSO regression, we developed an Anastomotic Score system on postoperative Day 3 (AScore-POD3), which yielded high diagnostic efficacy in the primary cohort (the area under the curve (AUC) = 0.87). The predictive value of AScore-POD3 was validated in the validation cohort, and its AUC was 0.83. We further built an AScore-POD3 based nomogram by combining the AScore-POD3 system with other clinical risk factors of AL. The C-index of the nomogram was 0.93 in the primary cohort and 0.82 in the validation cohort.

CONCLUSIONS

Our study suggests that AL can be early diagnosed after gastric cancer surgery by measuring drainage IFs.

Predictive and Diagnostic Biomarkers of Anastomotic Leakage: A Precision Medicine Approach for Colorectal Cancer Patients

Development of an anastomotic leak (AL) following intestinal surgery for the treatment of colorectal cancers is a life-threatening complication. Failure of the anastomosis to heal correctly can lead to contamination of the abdomen with intestinal contents and the development of peritonitis. The additional care that these patients require is associated with longer hospitalisation stays and increased economic costs. Patients also have higher morbidity and mortality rates and poorer oncological prognosis. Unfortunately, current practices for AL diagnosis are non-specific, which may delay diagnosis and have a negative impact on patient outcome. To overcome these issues, research is continuing to identify AL diagnostic or predictive biomarkers. In this review, we highlight promising candidate biomarkers including ischaemic metabolites, inflammatory markers and bacteria. Although research has focused on the use of blood or peritoneal fluid samples, we describe the use of implantable medical devices that have been designed to measure biomarkers in peri-anastomotic tissue. Biomarkers that can be used in conjunction with clinical status, routine haematological and biochemical analysis and imaging have the potential to help to deliver a precision medicine package that could significantly enhance a patient's post-operative care and improve outcomes. Although no AL biomarker has yet been validated in large-scale clinical trials, there is confidence that personalised medicine, through biomarker analysis, could be realised for colorectal cancer intestinal resection and anastomosis patients in the years to come.

Monitoring of patients with microdialysis following pancreaticoduodenectomy-the MINIMUM study: study protocol for a randomized controlled trial

BACKGROUND

Postoperative pancreatic fistula after pancreatoduodenectomy is a much-feared complication associated with substantial mortality and morbidity. The current standard for diagnosing postoperative pancreatic fistula, besides routine clinical examination, include radiological examinations, analysis of pancreatic drain amylase activity, and routine blood samples. Another promising method is by intraperitoneal microdialysis to monitor intraperitoneal metabolites measured at the pancreaticojejunostomy, thereby detecting what occurs locally, before chemical events can be reflected as measurable changes in systemic blood levels.

METHODS

The MINIMUM study is a prospective, randomized, controlled, single center enrolling 200 patients scheduled for open pancreatoduodenectomy comparing the microdialysis method to the "standard of care." Half of the included patients will be randomized to receive an intraperitoneal microdialysis catheter implanted at the end of surgery and will be monitored by microdialysis as an additional monitoring tool. The other half of the patients will not receive a microdialysis catheter and will be monitored according to the current standard of care. The primary objective is to evaluate if the microdialysis method can reduce the total length of stay at the hospital. Secondary endpoints are the frequency of complications, length of stay at the hospital at our institution, catheter malfunction, number of infections and bleeding episodes caused by the microdialysis catheter, patient-reported quality of life and pain, and cost per patient undergoing pancreatoduodenectomy. The patients will be randomized in a 1:1 ratio.

DISCUSSION

Intraabdominal microdialysis could potentially reduce morbidity and mortality after pancreatoduodenectomy. Furthermore, there is a great potential for shortening the in-hospital length of stay and reducing the financial aspect considerably. This study may potentially open the possibility for using microdialysis as standard monitoring in patients undergoing pancreatoduodenectomy. The hypothesis is that the microdialysis method compared to "standard care" will reduce the total length of hospital stay.

TRIAL REGISTRATION

Clinicaltrials.gov ( NCT03631173 ). Registered on 7 September 2018 under the name: "Monitoring of patients With Microdialysis Following Pancreaticoduodenectomy". Based on protocol version 19-1, dated 15th January 2019.

In Vivo Monitoring of Acetylcholine Release from Nerve Endings in Salivary Gland

Simple Summary

Stimulation of the parasympathetic nervous system results in the secretion of saliva. Previous studies have demonstrated acetylcholine content in homogenate obtained from salivary glands. Acetylcholine in homogenate, however, includes that stored in the cells, as well as that released in the interstitial fluid. The activity of the parasympathetic nervous system is mainly determined by the amount of acetylcholine released. We established an in vivo microdialysis method for monitoring the acetylcholine released from nerve endings in the salivary glands in rats. The results of the present study demonstrated that acetylcholine levels in the dialysate reflect acetylcholine levels in the interstitial fluid of the submandibular gland, and that an increase in the acetylcholine level in the dialysate depends predominantly on the release of acetylcholine from the parasympathetic nerve endings.

Abstract

A microdialysis technique was used to monitor acetylcholine levels in the local interstitial fluid in rat submandibular glands, with the aim of determining parasympathetic nerve activity in vivo. The dialysis probe housed a 10 × 0.22 mm semipermeable membrane (molecular weight cutoffs: 50,000 Da). When the probe was perfused at 2 μL/min in vitro, the mean relative recovery of acetylcholine was 41.7% ± 2.5%. The dialysis probes were implanted in the submandibular glands of anesthetized rats and perfusion with Ringer’s solution, at 2 μL/min, was performed. Acetylcholine concentrations in the dialysate were measured by high-performance liquid chromatography and electrochemical detection. The results revealed the following: (1) that mixing Eserine with Ringer’s solution allowed acetylcholine in the salivary glands to be quantified; (2) that acetylcholine concentrations in the dialysate were highly variable and unstable over the first 120 min after probe implantation, but reached a nearly stable level (4.8 ± 2.7 nM) thereafter in the presence of 100 µM of Eserine; and (3) that electrical stimulation of the chorda tympani nerve, or perfusion with high potassium Ringer’s solution, significantly increased acetylcholine concentrations in the dialysate. These results indicate that the present microdialysis technique offers a powerful tool for detecting changes in parasympathetic activity within the salivary glands.

Intraperitoneal microdialysis detects intestinal leakage earlier than hemodynamic surveillance and systemic inflammation in a pig model

OBJECTIVE

Anastomotic leakage is a common complication following large abdominal surgery, often developing to life-threatening abdominal sepsis due to late diagnosis. Currently, diagnostics rely on systemic hemodynamic and infection monitoring. We hypothesized that intraperitoneal microdialysis allows detection of peritonitis prior to changes in standard clinical parameters in a pig model.

MATERIALS AND METHODS

We included six pigs; five underwent intraperitoneal fecal contamination, one had sham surgery for a total of 10 h. Microdialysis was established in four intraabdominal quadrants and two hepatic lobes. All pigs were hemodynamically monitored with pulmonary artery and femoral artery catheters. Blood samples were assessed for inflammatory markers, terminal complement complex (TCC), interleukin (IL)-6, IL-10, and plasminogen activator inhibitor-1 (PAI-1).

RESULTS

Microdialysis showed intraperitoneal lactate increase during the first two hours after fecal contamination, which remained elevated throughout the observation time with concurrent decrease of glucose. Arterial lactate remained within reference range (<1,6mM). Systemic inflammatory markers TCC, IL-6, IL-10 and PAI-1 increased significantly after minimum four hours. Mean arterial pressure, stroke volume variation and cardiac output were not compromised the first five hours. Sham surgery did not influence any of the parameters.

CONCLUSION

Intraperitoneal fecal contamination leads to a rapid and pronounced intraperitoneal increase in lactate, decrease in glucose while pyruvate and glycerol levels remain unchanged. This distinct metabolic pattern of peritoneal inflammation can be easily detected by microdialysis. Observation of this pattern may minimize time to safe diagnosis of intestinal perforations after intraperitoneal fecal contamination.

Surface Microdialysis for Detection of Colorectal Anastomosis Ischemia-An Experimental Study

BACKGROUND

Inadequate blood supply is one of the major risk factors for anastomotic leak after low anterior rectal resection. Early detection of ischemia might predict complicated healing and enable anastomotic salvage, which is associated with better outcomes. A microdialysis offers a real-time evaluation of adequate bowel perfusion through monitoring of tissue metabolism. In this experimental study, we assessed the role of microdialysis in detecting early ischemia after colorectal anastomosis.

MATERIALS AND METHODS

Colorectal anastomosis was performed in six miniature pigs. A microdialysis catheter was placed on the bowel serosa 5 mm proximal to the anastomosis. Metabolic changes were monitored hourly before and after initiating ischemia, which was induced by ligation of the inferior mesenteric artery and skeletonization of the mesocolon.

RESULTS

Significant increase in tissue levels of lactate was detected after 60 min of ischemia (13.6 [10.4-16.1] versus 6.75 [1.8-9.6] mmol/L at baseline; P < 0.005). The lactate/pyruvate ratio increased accordingly. The concentration of glycerol increased significantly after 2 hours-from a baseline value of 29.5 (3-84) to 125 (79-201) mmol/L (P < 0.005). The decrease in glucose levels was also significant after 60 minutes-0 (0-0.2) versus 4.7 (3.3-6.8) mmol/L at baseline. However, its values started to decline before ischemia.

CONCLUSIONS

Surface microdialysis can detect ischemic changes early and may be a promising method in postoperative monitoring of colorectal anastomosis.

No Significant Effect of Daikenchuto (TJ-100) on Peritoneal IL-9 and IFN-γ Levels After Pancreaticoduodenectomy

Aim and Background

TJ-100 is a traditional Japanese medicine that affects inflammation and gastrointestinal motility, and is used as a preventive and treatment for paralytic ileus. This study aims at determining the effect of TJ-100 on the peritoneal levels of IFN-γ/IL-9, cytokines related to ileus, after pancreaticoduodenectomy (PD) in a clinical setting.

Methods

This was a subsidiary study of the clinical trial investigating the effect of TJ-100 on postoperative bowel function. Ascites was collected from 180 patients using an abdominal drainage tube on postoperative day 1 and 3 after PD (POD 1 or POD 3) and used to measure 27 cytokines. We performed univariate and multivariate analyses using several perioperative variables and administration of TJ-100/placebo to determine the effect of TJ-100 on the levels of IFN-γ and IL-9.

Results

Peritoneal levels of IL-9 and IFN-γ decreased between POD 1 and 3 (Wilcoxon signed-rank test p<0.001). Multivariate analysis was performed after univariate analysis to select the variables and patients with a body mass index of ≥22 kg/m², older age, use of epidural anesthesia, and longer surgery correlated with the levels of IL-9 and IFN-γ. However, we could not detect a correlation between the use of TJ-100 and cytokine levels in ascites either on POD 1 or 3.

Conclusion

TJ-100 did not affect peritoneal IL-9 and IFN-γ levels after PD. This was in accordance with published clinical findings showing no improvement in bowel function after PD and TJ-100 treatment.

Early Metabolic and Inflammatory Intraperitoneal Changes After Rectum Perforation

Purpose

Anastomotic leakage (AL) is the most dreaded complication in rectal surgery. It has a great impact on postoperative morbidity and mortality. This animal model, in which we have studied postoperative metabolic and inflammatory changes, is designed to imitate an AL.

Methods

Twelve pigs were randomized into 2 groups. In the experimental group, an iatrogenic rectal perforation was performed, with the control group having a sham operation. The 2 groups were followed for 10 hours after operation with regard to vital parameters, arterial lactate, and cytokines interleukin (IL) 1, IL6, and IL10 in the blood and intraperitoneally. Intraperitoneal microdialysis analyses of glucose, lactate, glycerol, and pyruvate were performed and the lactate/pyruvate ratio was calculated.

Results

Glucose levels were lower in the experimental group after 4 hours. After 7 hours, lactate and lactate/pyruvate ratio was higher in the experimental group. At the same time intraperitoneal cytokines IL6 and IL10 were higher in the experimental group. Blood samples showed higher IL6 after 7 hours in the experimental group.

Conclusion

In this study, several significant differences between the groups in metabolic and inflammatory values were detected. Further clinical studies are recommended to evaluate the importance of intraperitoneal metabolic and inflammatory analyses as a diagnostic tool for early identification of an AL.

Detection of early anastomotic leakage by intraperitoneal microdialysis after low anterior resection for rectal cancer: a prospective cohort study

AIM

Anastomotic leakage (AL) is a common and serious complication following sphincter-preserving surgery for rectal cancer. Early detection and intervention can improve clinical outcomes. The aim of this prospective cohort study was to compare intraperitoneal microdialysis with a clinical scoring system for early detection of AL.

METHOD

A microdialysis catheter was anchored near the anastomosis at low anterior resection (LAR) for rectal cancer. Peritoneal fluid samples were analysed (lactate, pyruvate, glucose and glycerol concentration) 4-hourly and compared with a daily clinical leak score (DULK = Dutch leakage). At day 7 a pelvic CT with rectal contrast enema was performed to establish if there had been a radiological leak.

RESULTS

In this two-centre study, 129 patients [median age 65 (26-82) years; 60.5% male] underwent LAR. The leak rate was 27% (grade A, n = 11; grade B, n = 12; grade C, n = 12). Receiver operator characteristic analysis demonstrated a lactate cut-off value of 9.8 mm and had 77% sensitivity, 82% specificity, 78% accuracy, a positive predictive value (PPV) of 58, a negative predictive value (NPV) of 88 (CI 79-94) and an area under the curve (AUC) of 0.9 for AL. This compared with a clinical score ≥ 4, which had 57% sensitivity, 79% specificity, 71% accuracy, a PPV of 46, a NPV of 82 and an AUC of 0.7 for AL. The mean day for a positive test when using delta lactate ≥ 6.3 mm was 1.6 days and for leak score ≥ 4 it was 3.3 days (NS).

CONCLUSION

When AL occurs, intraperitoneal lactate concentration increases over time, and at a certain cut-off has a higher sensitivity, specificity, accuracy, PPV and NPV than a clinical scoring system.

Results of postoperative microdialysis intraperitoneal and at the anastomosis in patients developing anastomotic leakage after rectal cancer surgery

Introduction: Anastomotic leakage postoperatively in patients operated with rectum resection and primary anastomosis is a common and feared complication. We have studied seven patients with an anastomotic leakage after surgery and compared them with 13 patients without complications.Methods: Metabolic measurements with microdialysis were done during the first seven postoperative days, with measurements of glucose, pyruvate, lactate and glycerol. The lactate/pyruvate ratio was calculated. Measurements were performed subcutaneously, intraperitoneally and at the anastomosis. The inflammatory cytokines, IL 6 and IL 10, were measured intravenously and intraperitoneally 48 hours postoperatively.Results: Intravenous and intraperitoneal IL 6 were higher in the leakage group. Around the small intestine (intraperitoneally), we found that patients developing anastomotic leakage had higher lactate and lactate/pyruvate ratio immediately after surgery. They also showed lower glycerol levels. At the anastomosis, we found higher lactate and lactate/pyruvate ratio in anastomotic leak patients after the fourth postoperative day.Conclusions: The results indicate that a possible mechanism behind an anastomotic leakage is an impaired circulation and thus insufficient saturation to the small intestine peroperatively. This develops into an inflammation both intraperitoneally and intravenously, which, if not reversed, spread within the gastrointestinal tract .The colorectal anastomosis is the most vulnerable part of the gastrointestinal tract postoperatively and hypoxia and inflammation may occur there, and an anastomosis leakage will be the consequence.

Drain fluid's pH predicts anastomotic leak in colorectal surgery: results of a prospective analysis of 173 patients

BACKGROUND

The early risk assessment of anastomotic leak (AL) after colorectal surgery is crucial. Several markers have been proposed, including peritoneal fluid's pH. Aim of the present study is to evaluate the role of drain fluid pH as predictor of AL.

METHODS

All patients undergoing colorectal surgery from January 2015 to December 2017 were considered eligible. Hartmann procedures, procedures including temporary ileostomy and emergency surgery were excluded. Drain fluid was submitted for pH and chemical-physical assessment on postoperative day 1 (POD1) and postoperative day 3 (POD3).

RESULTS

Out of 173 patients, those who developed AL showed a lower drain fluid's pH on POD1 and on POD3 compared to patients who did not (P<0.05). The plotted ROC curves identified 7.53 as pH cut-off on POD1 (AUC 0.80) and 7.21 on POD3 (AUC 0.86). With both the cut-offs, pH was an independent predictor of AL at multivariable analysis (P<0.001). pH<7.53 on POD1 and pH<7.21 on POD3 showed 93.75% sensitivity and 97% specificity respectively.

CONCLUSIONS

Drain fluid's pH on POD1 is useful to select patients who will not develop AL while on POD3 it might identify those requiring a more careful management.

Correlation between invasive microbiota in margin-surrounding mucosa and anastomotic healing in patients with colorectal cancer

BACKGROUND

Impaired anastomotic healing is one of the major complications resulting from radical resection in colorectal cancer (CRC). Accumulating evidence suggests that intestinal microbiota is correlated with anastomotic healing.

AIM

To explore the microbiota structural shift in margin-surrounding mucosa and evaluate the predictive ability of selected bacterial taxa for impaired anastomotic healing.

METHODS

Margin-surrounding mucosa samples derived from 37 patients were collected to characterize the microbial community structure by 16s rRNA gene sequencing. The patients were divided into two groups according to the healing status of anastomoses: well-healing group (n = 30) and impaired-healing group (n = 7). Statistic differences in bacteria taxa were compared by Wilcoxon test and chi-squared test. The predictive ability of the selected bacterial taxa for the healing status of anastomoses was evaluated by the area under the receiver operator characteristic curve.

RESULTS

Community structure shifts were observed in the impaired-healing group and well-healing group. Six bacterial species were found to be significantly correlated with anastomotic healing, and among these species, Alistipes shahii, Dialister pneumosintes, and Corynebacterium suicordis were considered as the predictive factors. Taking the known risk factor age into consideration, Alistipes shahii, Dialister pneumosintes, and Corynebacterium suicordis improved predictive ability for the healing status of anastomoses.

CONCLUSION

These data show that Alistipes shahii, Dialister pneumosintes, and Corynebacterium suicordis could be considered as supplementary factors in the prediction of anastomosis healing status in patients after CRC radical resection.

Peritoneal microdialysis as a tool for detecting anastomotic leakage in patients after left-side colon and rectal resection. A systematic review

OBJECTIVE

The objective was to evaluate peritoneal microdialysis in the detection of clinical anastomotic leakage after left-sided colon and rectal resection through a systematic review.

METHODS

A systematic review (PRISMA guidelines) based on a systematic search through PubMed, Cochrane Library, and EMBASE (1 February 2017) was performed. Methodological index of non-randomised studies score was selected to assess the methodological quality. Patient demographics and raw data for intraperitoneal microdialysis concentrations of glucose, lactate, glycerol and pyruvate for 5 d postoperative were obtained from the respective study groups.

RESULTS

Ten studies with a total of 128 patients were included. Thirty (23%) patients developed clinical anastomotic leakage. The area under the curve for intraperitoneal lactate concentration was significant higher in patients with anastomotic leakage (58.2; 95% CI 39.2, 77.2) compared with the no leakage group (41.0; 95% CI 35.2, 46.1; p = .007). Receiver operating characteristic curve analysis of the maximum measured lactate concentration demonstrated 25% sensitivity, 88% specificity and 74% accuracy for AL at a cut-off value of 9.8 mmol/L. The odds ratio for a 5 mmol/L increase in lactate in relation to the risk of AL was 2.9 (CI 1.1, 8.0).

CONCLUSIONS

Increased intraperitoneal lactate concentration within the first 5 d postoperative was significantly associated with clinical anastomotic leakage, but with low predictive values. The microdialysis method is not yet ready for clinical implication before large prospective studies have defined cut off values for a biologic marker in the setting of a clear definitions of leakage.

Microdialysis in Postoperative Monitoring of Gastrointestinal Organ Viability: A Systematic Review

BACKGROUND

Microdialysis is a technique for continuous measurement of extracellular substances. It may be used to monitor tissue viability. The clinical implications of using microdialysis as a tool in gastrointestinal surgery have yet to be defined. The aim of the present study was to evaluate the clinical significance of microdialysis with special attention to different markers measured to predict the clinical outcome of surgical patients.

METHODS

Embase, MEDLINE, and the Cochrane Library were searched systematically for human studies written in English. Study selection, data extraction, and quality assessment were performed independently by two authors. We included studies in which the microdialysis technique was used for postoperative monitoring of patients undergoing gastrointestinal surgery. To be eligible, studies had to compare patients with and without postoperative complications.

RESULTS

Twenty-six studies were included in this review. MINORS score ranged from 3 to 12 (median 10.5). Most studies showed that levels of biomarkers obtained by microdialysis correlated with the postoperative clinical course. Lactate, pyruvate, glucose, and glycerol were the most frequently measured biomarkers. Several studies found that changes in biomarkers in complicated patients preceded symptoms of complications and/or changes in conventional paraclinical methods of postoperative monitoring.

CONCLUSIONS

Studies show that microdialysis may have the potential to become a tool in postoperative surveillance of surgical patients. Larger randomized studies are needed to define the clinical implications of microdialysis.

Bilirubin, urobilinogen, pancreas elastase and bile acid in drain fluid. The GBUP-study: Analysis of biomarkers for a colorectal anastomotic leakage

Purpose

A colorectal anastomotic leakage (CAL) is a major complication after colorectal surgery and leads to high rates of morbidity and prolonged hospital stay. The study aims to evaluate the benefit of using bilirubin, urobilinogen, pancreas elastase and bile acid in the drain fluid (DF) as a predictive marker for the CAL.

Methods

From June 2015 to October 2017 100 patients, who underwent left hemicolectomy (LH), sigma resection (SR), high anterior resection (HAR), low anterior resection (LAR) or reversal of Hartmann's Procedure (ROHP) were included in this monocentric non-randomized prospective clinical trial. During the first four postoperative days (POD) the concentration of bilirubin, urobilinogen, pancreas elastase and bile acid in the DF was measured.

Results

In total 100 patients were recruited. 17 were excluded due to intraoperative decisions to conduct a protective stoma. 6 patients had a CAL. The patients of the control group (n = 77) and the patients who suffered from a CAL (n = 6) had no increased concentration of urobilinogen and pancreas elastase in the DF. The concentration of bile acid in the DF of the patients who suffered from a CAL differed from those of the control group on the 4th POD (p = 0.055).

The concentration of bilirubin in the DF of the patients who suffered from a CAL significantly differed from those of the control group on the 1st POD (p = 0.031) and on the 3rd POD (p = 0.041).

Conclusion

Bilirubin and bile acid in the DF may function as a predictive marker for a CAL.

•

Bilirubin in the DF may function as a predictive marker for a CAL.

•

Bile acid in the DF may function as a predictive marker for a CAL.

•

Pancreas elastase in the DF did not seem to be a predictive marker for a CAL.

A new direction in anastomotic research: should we redesign the 'angle of sorrow'?

INTRODUCTION

Despite advances in oncological outcomes in colo-rectal surgery, rates of anastomotic leak have not improved. The precise mechanisms of anastomotic leak remain poorly understood. Current research has focused on anastomotic reinforcement to tackle anastomotic leak with little success. The 'Angle of Sorrow', the corner of the anastomosis is prone to anastomotic leak, but remains a persistent feature in the gastrointestinal anastomosis. The tendency for stress forces to concentrate in the vulnerable 'Angle of Sorrow' prompts the need for anastomotic design research.

AIM

The aim of this study is to explore if redesigning the 'Angle of Sorrow' can reduce the stress forces in the ileocolic anastomosis.

METHODS

A simulation-based experimental study compared two anastomotic designs: traditional Slit Enterotomy Anastomosis (SEA) vs a novel Radiused Enterotomy Anastomosis (REA). The finite element analysis simulations were performed using FEBIO to measure peak sheer stress in pressurised bowel.

RESULTS

Tissue stress was found to concentrate at the 'Angles of Sorrow' in traditional anastomosis design while the REA design distributed sheer stress across the anastomosis. The SEA model had greater peak sheer stress factors than REA for the hand-sewn and stapled 'Barcelona' anastomosis (1.58 (k) vs 0.64 (k), 0.91 (k) vs 0.63 (k)). The REA anastomosis resulted in significantly less peak stress across all anastomotic experiments (p = 0.0047). The mucosa of the SEA model tended to unfavourably evert.

CONCLUSION

Redesigning the 'Angle of Sorrow' decreased tissue stress concentration. The direction of future anastomotic research may involve going back to the drawing board, rather than attempting to reinforce a potentially flawed design. Despite advances in colorectal surgery, rates of anastomotic leak have not improved. The 'Angle of Sorrow', the corner of the anastomosis is prone to anastomotic leak, but remains a persistent feature in gastrointestinal anastomosis. The direction of future research may involve going back to redesign this vulnerable area.

Intraperitoneal lactate/pyruvate ratio and the level of glucose and glycerol concentration differ between patients surgically treated for upper and lower perforations of the gastrointestinal tract: a pilot study

BACKGROUND

Secondary peritonitis is a condition associated with high morbidity and mortality. Continuous postoperative monitoring of patients to ensure timely intervention to treat complications without delay is important for survival and outcome. We aimed to (1) investigate potential differences in postoperative intraperitoneal biomarker levels between patients with upper and lower gastrointestinal tract lesion, and (2) compare postoperative biomarker levels between complicated and uncomplicated patients.

METHODS

We included a total of 15 consecutive patients operated for upper (n = 7) and lower (n = 8) gastrointestinal tract perforation. We registered postoperative complications during a 30 days follow up-period. Complications were defined as intraabdominal complications, septic shock, and mortality. 5 patients were complicated. A microdialysis catheter was placed intraperitoneally in each patient. Samples were collected every 4th hour for up to 7 postoperative days. Samples were analysed for concentrations of glucose, lactate, pyruvate and glycerol.

RESULTS

Microdialysis results showed that patients with upper gastrointestinal tract lesions had significantly higher levels of postoperative intraperitoneal glucose and glycerol concentrations, as well as lower lactate/pyruvate ratios and lactate/glucose ratios. In the group with perforation of the lower gastrointestinal tract, those patients with a complicated course showed lower levels of postoperative intraperitoneal glucose concentration and glycerol concentration and higher lactate/pyruvate ratios and lactate/glucose ratios than those patients with an uncomplicated course.

CONCLUSION

Patients with upper and lower gastrointestinal tract lesions showed differences in postoperative biomarker levels. A difference was also seen between patients with complicated and uncomplicated postoperative courses.

Peritoneal fluid biomarkers in the detection of colorectal anastomotic leaks: a systematic review

PURPOSE

Anastomotic leak (AL) in colorectal surgery leads to significant morbidity, mortality and poorer oncological outcomes. Diagnosis of AL is frequently delayed as current methods of detection are not 100% sensitive or specific. 'Biomarkers', such as cytokines and markers of ischaemia, from the milieu of the anastomosis may aid early detection. This paper aims to review the evidence for their role in AL detection, allowing identification of targets for future research.

METHODS

A systematic review was performed using PubMed, MEDLINE and Cochrane Library databases. Papers concerning detection or prediction of AL with biomarkers were identified. References within the papers were used to identify further relevant articles.

RESULTS

Research has taken place in small cohorts with varying definitions of AL. Lactate has consistently been shown to be elevated in patients with intra-abdominal complications and ALs. pH on post-operative day 3 showed excellent specificity. Despite mixed results, a meta-analysis found that the cytokines tumour necrosis factor-α and interleukin-6 were elevated early in AL. Detection of bacteria in drain fluid by RT-PCR has good specificity but a high rate of false positives.

CONCLUSIONS

Peritoneal cytokines, lactate and pH have the potential to identify AL early. The consistency of the results for lactate and pH, alongside the fact that they are easy, quick and inexpensive to test, makes them the most attractive targets. Studies in larger cohorts with standardized definitions of AL are required to clarify their usefulness. Emerging biosensor technology may facilitate the development of small, low-cost and degradable intra-abdominal devices to measure peritoneal fluid biomarkers.

Systematic review of the role of biomarkers in diagnosing anastomotic leakage following colorectal surgery

BACKGROUND

Anastomotic leakage (AL) following colorectal surgery can be difficult to diagnose owing to varying clinical presentations. This systematic review aimed to assess biomarkers as potential diagnostic tests for preclinical detection of AL.

METHODS

A comprehensive literature review was conducted according to PRISMA guidelines. All published studies evaluating biomarkers, both systemic and peritoneal, in the context of AL following colorectal surgery were included. Studies were sought in three electronic databases (MEDLINE, PubMed and Embase) from January 1990 to June 2016.

RESULTS

Thirty-six studies evaluated 51 different biomarkers in the context of AL after colorectal surgery. Biomarkers included markers of ischaemia and inflammation, and microbiological markers, and were measured in both peritoneal drain fluid and the systemic circulation. The most commonly evaluated peritoneal drain fluid biomarkers were interleukin (IL) 6, IL-10 and tumour necrosis factor. Significantly raised drain levels in the early postoperative period were reported to be associated with the development of AL. C-reactive protein, procalcitonin and leucocytes were the most commonly evaluated systemic biomarkers with significant negative and positive predictive values. Associated area under the curve values ranged from 0·508 to 0·960.

CONCLUSION

Peritoneal drain fluid and systemic biomarkers are poor predictors of AL after colorectal surgery. Combinations of these biomarkers showed improvement in predictive accuracy.

Predicting Value of Serum Procalcitonin, C-Reactive Protein, Drain Fluid Culture, Drain Fluid Interleukin-6, and Tumor Necrosis Factor-α Levels in Anastomotic Leakage after Rectal Resection

BACKGROUND

Anastomotic leak is the most dreaded septic complication of colorectal surgical procedures. Death is proportional to the time between occurrence and diagnosis of the leakage. Biomarkers, which may help to predict anastomotic leakage before appearance of its clinical features, may be beneficial in preventing adverse outcomes. This study investigates a biomarker that might be useful to predict rectal anastomotic leakage before its clinical presentation.

PATIENTS AND METHODS

Serum procalcitonin and C-reactive protein (CRP) levels, bacterial proliferation, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels of drain fluid were evaluated in 50 consecutive patients who underwent low anterior resection without diverting ostomy for rectal carcinoma.

RESULTS

Anastomotic leakage occurred in seven of 50 (14%) patients. Serum CRP and procalcitonin levels at post-operative day three were higher in patients with anastomotic leakage (p = 0.01, p = 0.02 respectively). Drain TNF-α values were increased 63.2% on post-operative day five when compared with post-operative day three in patients with anastomotic leakage, but were decreased in patients without leakage. There was no statistical difference for drain IL-6 levels between groups. The bacterial proliferation rate of drain fluid culture in the leakage group was 42.9% at post-operative day three and 85.7% at post-operative day five (p = 0.29 and p = 0.0001, respectively).

CONCLUSIONS

High serum CRP and procalcitonin values on post-operative day three are alarming, and assessment of anastomotic leakage by abdominal imaging with rectal contrast is suggested. In addition, increasing levels of TNF-α and bacterial proliferation in drain fluid are predictive, whereas IL-6 is not.

Deep Pelvic Surgical Site Infection After Radiotherapy and Surgery for Locally Advanced Rectal Cancer

BACKGROUND

High morbidity, increased mortality, and impaired long-term oncologic outcome have been reported after deep surgical site infection (SSI) in rectal cancer surgery. The rate, risk factors and consequences of deep SSI after (chemo)radiotherapy [(C)RT], and surgery for locally advanced rectal cancer (LARC) in a tertiary university hospital single centre cohort of 540 patients are presented.

METHODS

Patients with LARC, operated between January 1, 2007 and December 31, 2015, were identified in the institutional prospective database. All patients had tumours threatening the mesorectal fascia or invading adjacent organs, with a high rate of T4 tumours (60 %), and all received (C)RT. Risk factors for deep SSI were calculated by multivariable logistic regression analysis. Morbidity data were assessed. Overall survival (OS) and disease-free survival (DFS) between patients with or without deep SSI were estimated.

RESULTS

Of 540 patients, 104 (19 %) experienced a deep SSI, with the highest rate in the abdominoperineal resection (APR) group with 25 %. APR, good response to (C)RT (low tumour regression grade), age, and operative blood loss were identified as significant (P < 0.05) risk factors for deep SSI in multivariable analysis. No difference was found in OS (P = 0.995) or DFS (P = 0.568). Hospital stay increased with 5 days (P < 0.001), and complete wound healing at the 3-month follow-up decreased from 86 to 45 % (P < 0.001) after deep SSI.

CONCLUSIONS

Deep SSI is a frequent and major complication after rectal surgery for LARC, with high morbidity, increased hospital stay and protracted wound healing. Interestingly, deep SSI did not influence long-term oncologic outcome.

Integrated approach to colorectal anastomotic leakage: Communication, infection and healing disturbances

Colorectal anastomotic leakage (CAL) remains a major complication after colorectal surgery. Despite all efforts during the last decades, the incidence of CAL has not decreased. In this review, we summarize the available strategies regarding prevention, prediction and intervention of CAL and categorize them into three categories: communication, infection and healing disturbances. These three major factors actively interact during the onset of CAL. We aim to provide an integrated approach to CAL based on its etiology. The intraoperative air leak test, intraoperative endoscopy, radiological examinations and stoma construction mainly aim to detect and to prevent communication between the intra- and extra-luminal content. Other strategies including postoperative drainage, antibiotics, and infectious-parameter evaluation are intended to detect and prevent anastomotic or peritoneal infection. Most currently available interventions for CAL focus on the control of communication and infection, while strategies targeting the healing disturbances such as lifestyle changes, oxygen therapy and evaluation of metabolic biomarkers still lack wide clinical application. This simplified categorization may contribute to an integrated understanding of CAL. We strongly believe that this integrated approach should be taken into consideration during clinical practice. An integrated approach to CAL could contribute to a better understanding of the etiology of CAL and eventually better patient outcome.

Evaluation of data from 35 dogs pertaining to dehiscence following intestinal resection and anastomosis

The objectives of this study were to evaluate blood and abdominal fluid lactate and glucose, fluid cytology, culture, and volume 24 and 48 hr following intestinal resection and anastomosis in dogs with and without closed-suction drains and to correlate findings with survival. Thirty-five client-owned dogs that underwent intestinal resection and anastomosis were prospectively enrolled in the study. Abdominal fluid was submitted for culture at surgery and again 24 hr postoperatively. Twenty-four and 48 hr postoperatively, blood and abdominal fluid glucose and lactate were measured and fluid was submitted for cytology. Abdominal fluid was collected either from a closed-suction drain or by abdominocentesis. Patients were followed either for 14 days or until death. Comparisons were made based on development of dehiscence and presence or absence of a drain. Patients with dehiscence were more likely to have positive cultures at 24 hr and to have had more bowel resected. Surviving patients without drains had significantly smaller differences in blood and fluid glucose and lactate both 24 and 48 hr postoperatively than surviving patients with drains. The significant differences identified between patients with and without drains suggests a need for further research into the effect of drains on abdominal fluid values.

Peritoneal Cytokine Levels Can Predict Anastomotic Leak on the First Postoperative Day

BACKGROUND

Accumulating evidence suggests that peritoneal cytokine concentrations may predict anastomotic leak after colorectal surgery, but previous studies have been underpowered.

OBJECTIVE

We aimed to test this hypothesis by using a larger prospectively collected data set.

DESIGN

This study is an analysis of prospectively collected data.

SETTINGS

This study was conducted at 3 public hospitals in Auckland, New Zealand.

PATIENTS

Patients undergoing colorectal surgery recruited as part of 3 previous randomized controlled trials were included.

MAIN OUTCOME MEASURES

Data on peritoneal and plasma levels of interleukin-6, interleukin-8, interleukin-10, and tumor necrosis factor-α on day 1 after colorectal surgery were reanalyzed to evaluate their predictive value for clinically important anastomotic leak. Area under receiver operating characteristic curve analysis was performed.

RESULTS

A total of 206 patients with complete cytokine data were included. The overall anastomotic leak rate was 8.3%. Concentration levels of peritoneal interleukin-6 and interleukin-10 on day 1 after colorectal surgery were predictive of anastomotic leak (area under receiver operating characteristic curve, 0.72 and 0.74; p = 0.006 and 0.004). Plasma cytokine levels of interleukin-6 were higher on day 1 after colorectal surgery in patients who had an anastomotic leak, but this was a poor predictor of anastomotic leak. Levels of other peritoneal and plasma cytokines were not predictive.

LIMITATIONS

The study was not powered a priori for anastomotic leak prediction. Although the current data do suggest that peritoneal levels of interleukin-6 and interleukin-10 are predictive of leak, the discriminative value in clinical practice remains unclear.

CONCLUSIONS

Peritoneal levels of interleukin-6 and interleukin-10 on day 1 after colorectal surgery can predict clinically important anastomotic leak.

Cytokines as Early Markers of Colorectal Anastomotic Leakage: A Systematic Review and Meta-Analysis

Purpose. Colorectal anastomotic leakage (CAL) is one of the most severe complications after colorectal surgery. This meta-analysis evaluates whether systemic or peritoneal inflammatory cytokines may contribute to early detection of CAL. Methods. Systematic literature search was performed in the acknowledged medical databases according to the PRISMA guidelines to identify studies evaluating systemic and peritoneal levels of TNF, IL-1β, IL-6, and IL-10 for early detection of CAL. Means and standard deviations of systemic and peritoneal cytokine levels were extracted, respectively, for patients with and without CAL. The meta-analysis of the mean differences was carried out for each postoperative day using Review Manager. Results. Seven articles were included. The meta-analysis was performed with 5 articles evaluating peritoneal cytokine levels. Peritoneal levels of IL-6 were significantly higher in patients with CAL compared to patients without CAL on postoperative days 1, 2, and 3 (P < 0.05). Similar results were found for peritoneal levels of TNF but on postoperative days 3, 4, and 5 (P < 0.05). The articles regarding systemic cytokine levels did not report any significant difference accordingly. Conclusion. Increased postoperative levels of peritoneal IL-6 and TNF are significantly associated with CAL and may contribute to its early detection.

Intraperitoneal microdialysis as a monitoring method in the intensive care unit

Studies on surgical patients provide some evidence of prompt detection of enteric ischemia with microdialysis. The purpose of the study was to measure intraperitoneal microdialysis values (glucose, glycerol, pyruvate, and lactate) in patients hospitalized in an intensive care unit (ICU) with an underlying abdominal surgical condition and to correlate these values with patients' outcomes. Twenty-one patients, 10 female, were enrolled in the study. The intraperitoneal metabolite values were measured for 3 consecutive days, starting from the first day of ICU hospitalization. Descriptive and inferential statistics were performed. The t-test, repeated measures analysis, Holm's test, and a logistic regression model were applied. Level of statistical significance was set at P = 0.05. Mean age of participants was 68.10 ± 8.02 years old. Survivors exhibited statistically significantly higher glucose values on day 3 (6.61 ± 2.01 against 3.67 ± 1.62; P = 0.002). Mean lactate/ pyruvate (L/P) values were above 20 (35.35 ± 27.11). All non-survivors had a mean three day L/P values greater than 25.94. Low L/P values were related to increased survival possibilities. High microdialysis glucose concentration, high L/P ratio and low glucose concentration were the major findings during the first three ICU hospitalization days in non-survivors. Intraperitoneal microdialysis may serve as a useful tool in understanding enteric ischemia pathophysiology.

Early Diagnosis of Colonic Anastomotic Leak With Peritoneal Endoscopy

Background and Objectives:

At present, we do not have a reliable method for the early diagnosis of colorectal anastomotic leakage (AL). We tested peritoneal flexible endoscopy through a port placed in the abdominal wall in the early postoperative course, as a new diagnostic method for detection of this complication and evaluated the suggested method for safety, feasibility, and accuracy.

Methods:

Ten swine were randomized into 2 groups: group A, colorectal anastomosis without leakage; and group B, colorectal anastomosis with leakage. A button gastrostomy feeding tube was inserted percutaneously into the peritoneal cavity. Colorectal anastomosis (with or without defect) was created 48 hours after the first operation. The swine were examined by peritoneal flexible endoscopy 8 and 24 hours after the colonic operation, by a consultant surgeon who was blinded to both the presence and the allocated location of the of the anastomotic defect.

Results:

None of the animals showed signs of illness 48 hours after the intraperitoneal gastrostomy tube placement. More than half of the anastomosis circumference was identified in 60 and 10% of the animals at endoscopy 8 and 24 hours, respectively, after the anastomosis was created. Excessive adhesion formation was observed in all animals, irrespective of AL. The sensitivity and specificity of endoscopy in detecting peritonitis 24 hours after AL were both 60%.

Conclusions:

Peritoneal endoscopy is a safe and simple procedure. Visualization of the peritoneal cavity in the early postoperative course was limited due to adhesion formation. Further studies are needed to clarify the accuracy of the procedure and to address additional methodological concerns.

Improving the outcomes in oncological colorectal surgery

During the last several decades, colorectal cancer surgery has experienced some major perioperative improvements. Preoperative risk-assessment of nutrition, frailty, and sarcopenia followed by interventions for patient optimization or an adapted surgical strategy, contributed to improved postoperative outcomes. Enhanced recovery programs or fast-track surgery also resulted in reduced length of hospital stay and overall complications without affecting patient safety. After an initially indecisive start due to uncertainty about oncological safety, the most significant improvement in intraoperative care was the introduction of laparoscopy. Laparoscopic surgery for colon and rectal cancer is associated with better short-term outcomes, whereas long-term outcomes regarding survival and recurrence rates are comparable. Nevertheless, long-term results in rectal surgery remain to be seen. Early recognition of anastomotic leakage remains a challenge, though multiple improvements have allowed better management of this complication.

Cytokine response in peripheral blood indicates different pathophysiological mechanisms behind anastomotic leakage after low anterior resection: a pilot study

BACKGROUND

Anastomotic leakage (AL) after rectosigmoid resection is a serious complication associated with high morbidity and mortality. This case-control pilot study investigated the changes in blood concentration of 10 different cytokines and 2 complement factors in relation to symptomatic AL after low anterior resection for rectosigmoid cancer.

METHODS

Fifty patients scheduled for resection of rectosigmoid cancer had blood samples taken the day before surgery and on post-operative days 1, 3 and 5. Four patients with symptomatic AL were identified. Twenty-two age- and disease-matched patients constituted the control group. The concentration of 10 cytokines (granulocyte macrophage colony-stimulating factor, interferon-γ, interleukin-1β, interleukin-2, interleukin-4, interleukin-5, interleukin-6, interleukin-8, interleukin-10 and tumour necrosis factor-α) and 2 complement factors (mannan-binding lectin and membrane attack complex) were measured.

RESULTS

The present study demonstrated that plasma concentration of interleukin-1β, interleukin-6, interleukin-8 and interleukin 10 within the first 5 post-operative days was increased in patients who developed early clinical AL, whereas there were no changes in patients with late-onset AL.

CONCLUSIONS

The demonstrated differences in the cytokine response in early and late AL may support the theory of different pathological mechanisms of AL.

Prediction and diagnosis of colorectal anastomotic leakage: A systematic review of literature

Although many studies have focused on the preoperative risk factors of anastomotic leakage after colorectal surgery (CAL), postoperative delay in diagnosis is common and harmful. This review provides a systematic overview of all available literature on diagnostic tools used for CAL. A systematic search of literature was undertaken using Medline, Embase, Cochrane and Web-of-Science libraries. Articles were selected when a diagnostic or prediction tool for CAL was described and tested. Two reviewers separately assessed the eligibility and level of evidence of the papers. Sixty-nine articles were selected (clinical methods: 11, laboratory tests: 12, drain fluid analysis: 12, intraoperative techniques: 22, radiology: 16). Clinical scoring leads to early awareness of probability of CAL and reduces delay of diagnosis. C-reactive protein measurement at postoperative day 3-4 is helpful. CAL patients are characterized by elevated cytokine levels in drain fluid in the very early postoperative phase in CAL patients. Intraoperative testing using the air leak test allows intraoperative repair of the anastomosis. Routine contrast enema is not recommended. If CAL is clinically suspected, rectal contrast-computer tomography is recommended by a few studies. In many studies a “no-test” control group was lacking, furthermore no golden standard for CAL is available. These two factors contributed to a relatively low level of evidence in the majority of the papers. This paper provides a systematic overview of literature on the available tools for diagnosing CAL. The study shows that colorectal surgery patients could benefit from some diagnostic interventions that can easily be performed in daily postoperative care.

Systematic review of methods to predict and detect anastomotic leakage in colorectal surgery

AIM

Anastomotic leakage is a serious complication of gastrointestinal surgery resulting in increased morbidity and mortality, poor function and predisposing to cancer recurrence. Earlier diagnosis and intervention can minimize systemic complications but is hindered by current diagnostic methods that are non-specific and often uninformative. The purpose of this paper is to review current developments in the field and to identify strategies for early detection and treatment of anastomotic leakage.

METHOD

A systematic literature search was performed using the MEDLINE, Embase, PubMed and Cochrane Library databases. Search terms included 'anastomosis' and 'leak' and 'diagnosis' or 'detection' and 'gastrointestinal' or 'colorectal'. Papers concentrating on the diagnosis of gastrointestinal anastomotic leak were identified and further searches were performed by cross-referencing.

RESULTS

Computerized tomography CT scanning and water-soluble contrast studies are the current preferred techniques for diagnosing anastomotic leakage but suffer from variable sensitivity and specificity, have logistical constraints and may delay timely intervention. Intra-operative endoscopy and imaging may offer certain advantages, but the ability to predict anastomotic leakage is unproven. Newer techniques involve measurement of biomarkers for anastomotic leakage and have the potential advantage of providing cheap real-time monitoring for postoperative complications.

CONCLUSION

Current diagnostic tests often fail to diagnose anastomotic leak at an early stage that enables timely intervention and minimizes serious morbidity and mortality. Emerging technologies, based on detection of local biomarkers, have achieved proof of concept status but require further evaluation to determine whether they translate into improved patient outcomes. Further research is needed to address this important, yet relatively unrecognized, area of unmet clinical need.

Little consensus in either definition or diagnosis of a lower gastro-intestinal anastomotic leak amongst colorectal surgeons

PURPOSE

The purposes of this study were to assess the working definition of a colorectal anastomotic leak among colorectal surgeons and to survey the current approach to investigation and management of a patient with a suspected anastomotic leak.

METHODS

Online survey consisting of nine questions regarding the definition, assessment and investigation of anastomotic leaks was conducted. Of the 738 eligible ACP members contacted, 210 responded (28.4%).

RESULTS

Results demonstrated that 94.2% of surgeons agreed 'extravasation of contrast on enema' and 91.8% agreed 'faecal material seen in drains/from the wound' constituted a clinical leak. Only 69.2% agreed that a leak was 'intra-abdominal sepsis requiring a laparotomy', and about half agreed that radiological collections constituted a leak when either treated with antibiotics (46.6%) or with percutaneous drainage (51.4%). Serial clinical examination was the perceived most sensitive clinical feature for a leak, with 75% of surgeons ranking this in their top three choices. Surgeons radiologically confirm a leak on average in 80.2% of cases. A CT with rectal contrast for a left-sided leak was selected by 42.9% of respondents. For a right-sided/small bowel anastomosis, 44.5% selected a CT with oral contrast and 43.4% a CT with IV contrast.

CONCLUSIONS

There is still significant heterogeneity between surgeons in what they define as an anastomotic leak. Most surgeons valued clinical examination as the most sensitive initial tool for leak detection; however, radiology has a major role in the confirmation of clinical leaks in colorectal patients. There is an increasing need to be able to classify and grade anastomotic leaks, both to improve the care of patients and for audit purposes.

Identification of anastomotic leakage after colorectal surgery using microdialysis of the peritoneal cavity

BACKGROUND

Early detection of colorectal anastomotic leakage (AL) may lead to better outcome. AL may be preceded by change in local metabolism and local ischaemia. Microdialysis of the peritoneal cavity is able to measure these changes in real-time and is minimally invasive. The aim of this prospective cohort study was to compare values of intraperitoneal microdialysis in patients with AL to patients without AL after open and laparoscopic colorectal surgery.

METHODS

Twenty-four patients underwent surgery for left-sided, sigmoid and rectal carcinoma with creation of an anastomosis. Intraoperatively a juxta-anastomotical intraperitoneal and subcutaneous microdialysis catheter was placed. The levels of lactate, pyruvate, glucose and glycerol in the dialysate were measured every 4 h during the first 5 post-operative days, and mean values and area under the curve (AUC) were calculated.

RESULTS

Mortality was 0 % and morbidity 38 %. In 3 patients (17 %), AL occurred. In patients with AL, post-operative peritoneal lactate level was 3.2 mmol/l (standard deviation (SD) 0.9) for patients without AL, compared to 4.4 mmol/l (SD 1.5) in case of AL (p = 0.03 for AUC). Intraperitoneal glucose levels were 8.1 mmol/l (SD 1.3), compared to 7.8 mmol/l (SD 2.2) in the complicated course (ns for AUC). Mean intraperitoneal lactate/pyruvate-ratio was 19.2 (SD 3) after colorectal surgery without AL compared to 25 (SD 4.7) in case of AL (non-significant (ns) for AUC). No significant differences were observed between patients who underwent laparoscopic resection and those who underwent open resection.

CONCLUSIONS

Anastomotic leakage was preceded by a significantly higher AUC and mean value of lactate levels during the first 5 post-operative days. To identify cut-off values for clinical use, pooling of data is necessary.

Intra-peritoneal microdialysis and intra-abdominal pressure after endovascular repair of ruptured aortic aneurysms

OBJECTIVES

This study aims to evaluate intra-peritoneal (ip) microdialysis after endovascular aortic repair (EVAR) of ruptured abdominal aortic aneurysm (rAAA) in patients developing intra-abdominal hypertension (IAH), requiring abdominal decompression.

DESIGN

Prospective study.

MATERIAL AND METHODS

A total of 16 patients with rAAA treated with an emergency EVAR were followed up hourly for intra-abdominal pressure (IAP), urine production and ip lactate, pyruvate, glycerol and glucose by microdialysis, analysed only at the end of the study. Abdominal decompression was performed on clinical criteria, and decompressed (D) and non-decompressed (ND) patients were compared.

RESULTS

The ip lactate/pyruvate (l/p) ratio was higher in the D group than in the ND group during the first five postoperative hours (mean 20 vs. 12), p = 0.005 and at 1 h prior to decompression compared to the fifth hour in the ND group (24 vs. 13), p = 0.016. Glycerol levels were higher in the D group during the first postoperative hours (mean 274.6 vs. 121.7 μM), p = 0.022. The IAP was higher only at 1 h prior to decompression in the D group compared to the ND group at the fifth hour (mean 19 vs. 14 mmHg).

CONCLUSIONS

Ip l/p ratio and glycerol levels are elevated immediately postoperatively in patients developing IAH leading to organ failure and subsequent abdominal decompression.

Treatment of colorectal anastomotic leakage: results of a questionnaire amongst members of the Dutch Society of Gastrointestinal Surgery

Anastomotic leakage after colorectal surgery is correlated with considerable morbidity and mortality. Although many studies focus on risk factors and detection, studies on the treatment strategy for colorectal anastomotic leakage are scarce. A national questionnaire amongst 350 members of the Dutch Society for Gastrointestinal Surgery was undertaken on the current treatment of colorectal anastomotic leakage. The response was 40% after two anonymous rounds. 27% of the respondents state that a leaking anastomosis above the level of the promontory should be salvaged in ASA 1-2 patients <80 years of age, for ASA 3 and/or >80 years of age this percentage is 7.3%. For an anastomosis under the promontory, 50% of the respondents choose preserving the anastomosis for ASA 1-2 compared to 17% for ASA 3 and/or >80 years of age. In ASA 1-2 patients with a local abscess after a rectum resection without protective ileostomy, 31% of the respondents will create an protective ileostomy, 40% break down the anastomosis to create a definite colostomy, in ASA 3 and/or >80 years of age 14% of the respondents create a protective ileostomy and 63% a definitive colostomy. In ASA 1-2 patients with peritonitis after a rectum resection with deviating ileostomy, 31% prefer a laparotomy for lavage and repair of the anastomosis, 25% for lavage without repair and 36% of the respondents prefer to break down the anastomosis. When the patient is ASA 3 and/or >80 years of age, 13% prefer repair, 9% a lavage and 74% breaking down the anastomosis. This questionnaire shows that in contrast to older people, more surgeons make an effort to preserve the anastomosis in younger people.

Clinical experience with microdialysis catheters in pediatric liver transplants

Ischemic vascular complications and rejection occur more frequently with pediatric liver transplants versus adult liver transplants. Using intrahepatic microdialysis catheters, we measured lactate, pyruvate, glucose, and glycerol values at the bedside for a median of 10 days in 20 pediatric liver grafts. Ischemia (n = 6), which was defined as a lactate level > 3.0 mM and a lactate/pyruvate ratio > 20, was detected without a measurable time delay with 100% sensitivity and 86% specificity. Rejection (n = 8), which was defined as a lactate level > 2.0 mM and a lactate/pyruvate ratio < 20 lasting for 6 or more hours, was detected with 88% sensitivity and 45% specificity. With additional clinical criteria, the specificity was 83% without a decrease in the sensitivity. Rejection was detected at a median of 4 days (range = 1-7 days) before alanine aminotransferase increased (n = 5, P = 0.11), at a median of 4 days (range = 2-9 days) before total bilirubin increased 25% or more (n = 7, P = 0.04), and at a median of 6 days (range = 4-11 days) before biopsy was performed (n = 8, P = 0.05). In conclusion, microdialysis catheters can be used to detect episodes of ischemia and rejection before current standard methods in pediatric liver transplants with clinically acceptable levels of sensitivity and specificity. The catheters were well tolerated by the children, and no major complications related to the catheters were observed.