Peritoneal negative pressure therapy prevents multiple organ injury in a chronic porcine sepsis and ischemia/reperfusion model. Shock. 2010;34:525-534. [PMID: 20823698 DOI: 10.1097/shk.0b013e3181e14cd2]

Vacuum-Assisted Closure Significantly Reduces Surgical Postoperative Complications Compared With Primary Abdominal Closure in Patients With Secondary Peritonitis: A Comparative Retrospective Study

BACKGROUND

Vacuum-assisted abdominal closure (VAC) is being increasingly used as an adjunctive procedure in the surgical treatment of secondary peritonitis. This study compared postoperative mortality and complication rates between VAC and primary abdominal closure (PAC).

METHOD

This retrospective chart review included all patients diagnosed with secondary peritonitis who underwent laparotomy between 2010 and 2019. Data were collected from six hospitals within Southern Denmark, covering a population of approximately 1,225,000 inhabitants.

RESULTS

The study involved 315 patients (139 in the PAC and 176 in the VAC groups). In the VAC group, BMI, ASA, SOFA, MPI, and four quadrant contamination was significantly higher at the index operation. There were no significant differences in nonadjusted and adjusted postoperative mortality at 30 days, 90 days, and 1 year, with cumulative values of 13%, 16%, and 21%, respectively, compared with 16%, 21%, and 31%, in the PAC group (p = 0.519, p = 0.380, and p = 0.051, respectively). Cumulative adjusted surgical postoperative complications at 30 days, 90 days, and 1 year, as assessed by the comprehensive complication index, was significantly higher in the PAC group. Reoperations were significantly more common in the PAC group. The total length of the intensive care unit admission was significantly longer in the VAC group, with a mean of 9.0 ± 12.1 versus 6.7 ± 12.1 days (p < 0.001).

CONCLUSION

VAC after laparotomy for secondary peritonitis did not significantly reduce mortality but increased ICU stay, whereas primary closure led to higher surgical complication rates and reoperations.

The intensity of subacute local biological effects after the implantation of ALBO-OS dental material based on hydroxyapatite and poly(lactide-co-glycolide): in vivo evaluation in rats

OBJECTIVES

This study aimed to evaluate the intensity of the subacute local biological effects after implantation and osseoconductive potential of novel hydroxyapatite-based bone substitute coated with poly (lactide-co-glycolide), named ALBO-OS, in comparison to Bio-Oss®.

METHODS

Fifteen male Wistar rats, randomly assigned into groups: 10, 20, and 30 days (n꞊5), were subcutaneously implanted with ALBO-OS and Bio-Oss®. Furthermore, artificially made bone defects on both rat's tibias were implanted with experimental materials. Unimplanted defects represented negative control. After the animals' euthanizing, tissue samples were prepared and analyzed histologically and histomorphometrically.

RESULTS

Normal healing of the epithelial tissue was observed, with no signs of infection or necrosis. Minimal vascular congestion was noted immediately around the graft, with no signs of tissue oedema, with a minimal capsule thickness. The applied material did not cause an inflammatory response (IR) of significant intensity, and 20 days after implantation, the IR was mainly assessed as minimal. The tibial specimen showed that ALBO-OS has good osseoconductive potential, similar to Bio-Oss®, as well as low levels of acute and subacute inflammation.

CONCLUSIONS

The tested material exhibits satisfying biocompatibility, similar to Bio-Oss®.

Multiple site inflammation and acute kidney injury in crush syndrome

Crush syndrome, which frequently occurs in earthquake disasters, often leads to rhabdomyolysis induced acute kidney injury (RIAKI). Recent findings indicate that systemic inflammatory response syndrome (SIRS) exacerbates muscle collapse, contributing to RIAKI. The purpose of this study is to investigate the involvement of multiple site inflammation, including intraperitoneal, in crush syndrome. In a mouse model of RIAKI, elevated levels of inflammatory mediators such as TNFα, IL-6, myoglobin, and dsDNA were observed in serum and the peritoneal cavity, peaking earlier in the intraperitoneal cavity than in serum or urine. Our previously developed novel peptide inhibiting leukocyte extracellular traps was administered intraperitoneally and blocked all of these mediators in the intraperitoneal cavity and serum, ameliorating muscle damage and consequent RIAKI. Although further studies are needed to determine whether intraperitoneal inflammation associated with muscle collapse can lead to systemic inflammation, resulting in more severe and prolonged muscle damage and renal injury, early suppression of multiple site inflammation, including intraperitoneal, might be an effective therapeutic target.

Experimental Vitamin D Deficiency in Rats: Clinical Chemistry, Histopathological, and Immunological Evaluation

BACKGROUND

Vitamin D deficiency is a significant global health concern. Experimental models are essential to elucidate the biochemical, histopathological, and immunological consequences of this deficiency. This study established a vitamin D deficiency rat model to mimic insufficient vitamin D intake and examine the resulting health impacts, particularly on liver, kidney, and immune functions.

MATERIALS AND METHODS

Sprague-Dawley male rats were randomly assigned to two groups. The control group received a standard rodent diet, while the experimental group was fed a modified diet with reduced vitamin D for three months. Analyses included serum vitamin D levels, clinical chemistry, renal and liver histopathology, and blood immunophenotyping and cytokine analysis for both the control (n=7) and experimental (n=7) groups.

RESULTS

Serum vitamin D 25-OH levels were threefold lower in the experimental group (p < 0.001), indicating the induction of vitamin D deficiency. No significant differences in weight gain were observed between the groups. All clinical chemistry parameters remained within reference ranges. However, the experimental group showed significant declines in triglycerides (TG, p=0.0441), alkaline phosphatase (ALP, p=0.0021), and alanine aminotransferase (ALT, p=0.0002). Histopathology revealed normal liver and kidney architecture in the control group, while the experimental group exhibited hepatic cord deterioration, severe vacuolization in the liver, and edema and dilatation in the renal cortex tubular epithelium. Immunophenotyping analysis of lymphocyte subsets and assessment of serum cytokines did not reveal any differences between the two groups.

CONCLUSION

A vitamin D deficiency model without complications such as obesity, parathyroid issues, or mortality was established in rats. This method could be applied in specific disease experimental models.

Open or closed abdomen post laparotomy to control severe abdominal sepsis: a survival analysis

INTRODUCTION

severe abdominal sepsis, accompained by diffuse peritonitis, poses a significant challenge for most surgeons. It often requires repetitive surgical interventions, leading to complications and resulting in high morbidity and mortality rates. The open abdomen technique, facilitated by applying a negative-pressure wound therapy (NPWT), reduces the duration of the initial surgical procedure, minimizes the accumulation of secretions and inflammatory mediators in the abdominal cavity and lowers the risk of abdominal compartment syndrome and its associated complications. Another approach is primary closure of the abdominal aponeurosis, which involves suturing the layers of the abdominal wall.

METHODS

the objective of this study is to conduct a survival analysis comparing the treatment of severe abdominal sepsis using open abdomen technique versus primary closure after laparotomy in a public hospital in the South of Brazil. We utilized data extracted from electronic medical records to perform both descriptive and survival analysis, employing the Kaplan-Meier curve and a log-rank test.

RESULTS

the study sample encompassed 75 laparotomies conducted over a span of 5 years, with 40 cases employing NPWT and 35 cases utilizing primary closure. The overall mortality rate observed was 55%. Notably, survival rates did not exhibit statistical significance when comparing the two methods, even after stratifying the data into separate analysis groups for each technique.

CONCLUSION

recent publications on this subject have reported some favorable outcomes associated with the open abdomen technique underscoring the pressing need for a standardized approach to managing patients with severe, complicated abdominal sepsis.

The role of curcumin during pregnancy on the exposed fetuses' tissues of Wistar rats to electromagnetic field

To investigate curcumin (CUR) as the protector against the harmful effects of low-frequency electromagnetic field(LF- EMF, 50 Hz) during pregnancy period, 5 males and 15 females of Wistar rat mated and vaginal plaques were observed. Then, the pregnant rats were divided into six groups. During pregnancy(21 days), the EMF group was exposed to EMF for 30 min/day, the CUR group received a single dose of 50 mg/kg/daily CUR intraperitoneal, the EMF+CUR group was injected CUR and exposed to EMF daily. The DMSO(dimethyl sulfoxide) group was injected solvent of CUR (DMSO) intraperitoneal with the same volume of CUR solvent, the sham group was placed through the solenoid in the same conditions as the first group without exposure and the control group was kept in their cage in normal condition. After four weeks, babies born were divided according to the mother groups and sacrificed. Then, the three tissues injuries were investigated. EMF exposure led to an increase in outstanding necrotic areas in hippocampal tissue, an increase in the amount of hyperemia(p = 0.017) and necrotic(p = 0.005) in kidneys, and degeneration in liver tissue(p = 0.007) in the EMF group compared with EMF+CUR groups. A single dose of CUR daily during pregnancy can protect these tissues from injuries caused by LF-EMF exposure in rat fetuses.

Optimal tentative abdominal closure for open abdomen: a multicenter retrospective observational study (OPTITAC study)

BACKGROUND

Primary fascia closure is often difficult following an open abdomen (OA). While negative-pressure wound therapy (NPWT) is recommended to enhance successful primary fascia closure, the optimal methods and degree of negative pressure remain unclear. This study aimed to elucidate optimal methods of NPWT as a tentative abdominal closure for OA to achieve primary abdominal fascia closure.

MATERIALS AND METHODS

A multicenter, retrospective, cohort study of adults who survived OA greater than 48 h was conducted in 12 institutions between 2010 and 2022. The achievement of primary fascia closure and incidence of enteroatmospheric fistula were examined based on methods (homemade, superficial NPWT kit, or open-abdomen kit) or degrees of negative pressure (<50, 50-100, or >100 mmHg). A generalized estimating equation was used to adjust for age, BMI, comorbidities, etiology for laparotomy requiring OA, vital signs, transfusion, severity of critical illness, and institutional characteristics.

RESULTS

Of the 279 included patients, 252 achieved primary fascia closure. A higher degree of negative pressure (>100 mmHg) was associated with fewer primary fascia closures than less than 50 mmHg [OR, 0.18 (95% CI: 0.50-0.69), P =0.012] and with more frequent enteroatmospheric fistula [OR, 13.83 (95% CI: 2.30-82.93)]. The methods of NPWT were not associated with successful primary fascia closure. However, the use of the open-abdomen kit was related to a lower incidence of enteroatmospheric fistula [OR, 0.02 (95% CI: 0.00-0.50)].

CONCLUSION

High negative pressure (>100 mmHg) should be avoided in NPWT during tentative abdominal closure for OA.

Damage control surgery in emergency general surgery: What you need to know

ABSTRACT

Damage-control surgery (DCS) is a strategy adopted to limit initial operative interventions in the unstable surgical patient, delaying definitive repairs and abdominal wall closure until physiologic parameters have improved. Although this concept of "physiology over anatomy" was initially described in the management of severely injured trauma patients, the approaches of DCS have become common in the management of nontraumatic intra-abdominal emergencies.While the utilization of damage-control methods in emergency general surgery (EGS) is controversial, numerous studies have demonstrated improved outcomes, making DCS an essential technique for all acute care surgeons. Following a brief history of DCS and its indications in the EGS patient, the phases of DCS will be discussed including an in-depth review of preoperative resuscitation, techniques for intra-abdominal source control, temporary abdominal closure, intensive care unit (ICU) management of the open abdomen, and strategies to improve abdominal wall closure.

Nanoscopic and Functional Characterization of Keratinocyte-Originating Exosomes in the Wound Fluid of Non-Diabetic and Diabetic Chronic Wound Patients

Exosomes, a class of extracellular vesicles of endocytic origin, play a critical role in paracrine signaling for successful cell-cell crosstalk in vivo. However, limitations in our current understanding of these circulating nanoparticles hinder efficient isolation, characterization, and downstream functional analysis of cell-specific exosomes. In this work, we sought to develop a method to isolate and characterize keratinocyte-originated exosomes (hExo κ ) from human chronic wound fluid. Furthermore, we studied the significance of hExo κ in diabetic wounds. LC-MS-MS detection of KRT14 in hExo κ and subsequent validation by Vesiclepedia and Exocarta databases identified surface KRT14 as a reliable marker of hExo κ . dSTORM nanoimaging identified KRT14+ extracellular vesicles (EV κ ) in human chronic wound fluid, 23% of which were of exosomal origin. An immunomagnetic two-step separation method using KRT14 and tetraspanin antibodies successfully isolated hExo κ from the heterogeneous pool of EV in chronic wound fluid of 15 non-diabetic and 22 diabetic patients. Isolated hExo κ (Ø75-150nm) were characterized per EV-track guidelines. dSTORM images, analyzed using online CODI followed by independent validation using Nanometrix, revealed hExo κ Ø as 80-145nm. The abundance of hExo κ was low in diabetic wound fluids and negatively correlated with patient HbA1c levels. The hExo κ isolated from diabetic wound fluid showed a low abundance of small bp RNA (<200 bp). Raman spectroscopy underscored differences in surface lipids between non-diabetic and diabetic hExo κ Uptake of hExo κ by monocyte-derived macrophages (MDM) was low for diabetics versus non-diabetics. Unlike hExo κ from non-diabetics, the addition of diabetic hExo κ to MDM polarized with LPS and INFγ resulted in sustained expression of iNOS and pro-inflammatory chemokines known to recruit macrophage (mϕ) This work provides maiden insight into the structure, composition, and function of hExo κ from chronic wound fluid thus providing a foundation for the study of exosomal malfunction under conditions of diabetic complications such as wound chronicity.

The open abdomen in trauma, acute care, and vascular and endovascular surgery: comprehensive, expert, narrative review

BACKGROUND

The open abdomen is an innovation that greatly improved surgical understanding of damage control, temporary abdominal closure, staged abdominal reconstruction, viscera and enteric fistula care, and abdominal wall reconstruction. This article provides an evidence-informed, expert, comprehensive narrative review of the open abdomen in trauma, acute care, and vascular and endovascular surgery.

METHODS

A group of 12 international trauma, acute care, and vascular and endovascular surgery experts were invited to review current literature and important concepts surrounding the open abdomen.

RESULTS

The open abdomen may be classified using validated systems developed by a working group in 2009 and modified by the World Society of the Abdominal Compartment Syndrome-The Abdominal Compartment Society in 2013. It may be indicated in major trauma, intra-abdominal sepsis, vascular surgical emergencies, and severe acute pancreatitis; to facilitate second look laparotomy or avoid or treat abdominal compartment syndrome; and when the abdominal wall cannot be safely closed. Temporary abdominal closure and staged abdominal reconstruction methods include a mesh/sheet, transabdominal wall dynamic fascial traction, negative pressure wound therapy, and hybrid negative pressure wound therapy and dynamic fascial traction. This last method likely has the highest primary fascial closure rates. Direct peritoneal resuscitation is currently an experimental strategy developed to improve primary fascial closure rates and reduce complications in those with an open abdomen. Primary fascial closure rates may be improved by early return to the operating room; limiting use of crystalloid fluids during the surgical interval; and preventing and/or treating intra-abdominal hypertension, enteric fistulae, and intra-abdominal collections after surgery. The majority of failures of primary fascial closure and enteroatmospheric fistula formation may be prevented using effective temporary abdominal closure techniques, providing appropriate resuscitation fluids and nutritional support, and closing the abdomen as early as possible.

CONCLUSION

Subsequent stages of the innovation of the open abdomen will likely involve the design and conduct of prospective studies to evaluate appropriate indications for its use and effectiveness and safety of the above components of open abdomen management.

Source control in emergency general surgery: WSES, GAIS, SIS-E, SIS-A guidelines

Intra-abdominal infections (IAI) are among the most common global healthcare challenges and they are usually precipitated by disruption to the gastrointestinal (GI) tract. Their successful management typically requires intensive resource utilization, and despite the best therapies, morbidity and mortality remain high. One of the main issues required to appropriately treat IAI that differs from the other etiologies of sepsis is the frequent requirement to provide physical source control. Fortunately, dramatic advances have been made in this aspect of treatment. Historically, source control was left to surgeons only. With new technologies non-surgical less invasive interventional procedures have been introduced. Alternatively, in addition to formal surgery open abdomen techniques have long been proposed as aiding source control in severe intra-abdominal sepsis. It is ironic that while a lack or even delay regarding source control clearly associates with death, it is a concept that remains poorly described. For example, no conclusive definition of source control technique or even adequacy has been universally accepted. Practically, source control involves a complex definition encompassing several factors including the causative event, source of infection bacteria, local bacterial flora, patient condition, and his/her eventual comorbidities. With greater understanding of the systemic pathobiology of sepsis and the profound implications of the human microbiome, adequate source control is no longer only a surgical issue but one that requires a multidisciplinary, multimodality approach. Thus, while any breach in the GI tract must be controlled, source control should also attempt to control the generation and propagation of the systemic biomediators and dysbiotic influences on the microbiome that perpetuate multi-system organ failure and death. Given these increased complexities, the present paper represents the current opinions and recommendations for future research of the World Society of Emergency Surgery, of the Global Alliance for Infections in Surgery of Surgical Infection Society Europe and Surgical Infection Society America regarding the concepts and operational adequacy of source control in intra-abdominal infections.

The unrestricted global effort to complete the COOL trial

BACKGROUND

Severe complicated intra-abdominal sepsis (SCIAS) has an increasing incidence with mortality rates over 80% in some settings. Mortality typically results from disruption of the gastrointestinal tract, progressive and self-perpetuating bio-mediator generation, systemic inflammation, and multiple organ failure. A further therapeutic option may be open abdomen (OA) management with negative peritoneal pressure therapy (NPPT) to remove inflammatory ascites and attenuate the systemic damage from SCIAS, although there are definite risks of leaving the abdomen open whenever it might possibly be closed. This potential therapeutic paradigm is the rationale being assessed in the Closed Or Open after Laparotomy (COOL trial) ( https://clinicaltrials.gov/ct2/show/NCT03163095 ). Initially, the COOL trial received Industry sponsorship; however, this funding mandated the use of a specific trademarked and expensive NPPT device in half of the patients allocated to the intervention (open) arm. In August 2022, the 3 M/Acelity Corporation without consultation but within the terms of the contract canceled the financial support of the trial. Although creating financial difficulty, there is now no restriction on specific NPPT devices and removing a cost-prohibitive intervention creates an opportunity to expand the COOL trial to a truly global basis. This document describes the evolution of the COOL trial, with a focus on future opportunities for global growth of the study.

METHODS

The COOL trial is the largest prospective randomized controlled trial examining the random allocation of SCIAS patients intra-operatively to either formal closure of the fascia or the use of the OA with an application of an NPPT dressing. Patients are eligible if they have free uncontained intraperitoneal contamination and physiologic derangements exemplified by septic shock OR severely adverse predicted clinical outcomes. The primary outcome is intended to definitively inform global practice by conclusively evaluating 90-day survival. Initial recruitment has been lower than hoped but satisfactory, and the COOL steering committee and trial investigators intend with increased global support to continue enrollment until recruitment ensures a definitive answer.

DISCUSSION

OA is mandated in many cases of SCIAS such as the risk of abdominal compartment syndrome associated with closure, or a planned second look as for example part of "damage control"; however, improved source control (locally and systemically) is the most uncertain indication for an OA. The COOL trial seeks to expand potential sites and proceed with the evaluation of NPPT agnostic to device, to properly examine the hypothesis that this treatment attenuates systemic damage and improves survival. This approach will not affect internal validity and should improve the external validity of any observed results of the intervention.

TRIAL REGISTRATION

National Institutes of Health ( https://clinicaltrials.gov/ct2/show/NCT03163095 ).

The unrestricted global effort to complete the COOL trial

BACKGROUND

Severe complicated intra-abdominal sepsis (SCIAS) has an increasing incidence with mortality rates over 80% in some settings. Mortality typically results from disruption of the gastrointestinal tract, progressive and self-perpetuating bio-mediator generation, systemic inflammation, and multiple organ failure. A further therapeutic option may be open abdomen (OA) management with negative peritoneal pressure therapy (NPPT) to remove inflammatory ascites and attenuate the systemic damage from SCIAS, although there are definite risks of leaving the abdomen open whenever it might possibly be closed. This potential therapeutic paradigm is the rationale being assessed in the Closed Or Open after Laparotomy (COOL trial) ( https://clinicaltrials.gov/ct2/show/NCT03163095 ). Initially, the COOL trial received Industry sponsorship; however, this funding mandated the use of a specific trademarked and expensive NPPT device in half of the patients allocated to the intervention (open) arm. In August 2022, the 3 M/Acelity Corporation without consultation but within the terms of the contract canceled the financial support of the trial. Although creating financial difficulty, there is now no restriction on specific NPPT devices and removing a cost-prohibitive intervention creates an opportunity to expand the COOL trial to a truly global basis. This document describes the evolution of the COOL trial, with a focus on future opportunities for global growth of the study.

METHODS

The COOL trial is the largest prospective randomized controlled trial examining the random allocation of SCIAS patients intra-operatively to either formal closure of the fascia or the use of the OA with an application of an NPPT dressing. Patients are eligible if they have free uncontained intraperitoneal contamination and physiologic derangements exemplified by septic shock OR severely adverse predicted clinical outcomes. The primary outcome is intended to definitively inform global practice by conclusively evaluating 90-day survival. Initial recruitment has been lower than hoped but satisfactory, and the COOL steering committee and trial investigators intend with increased global support to continue enrollment until recruitment ensures a definitive answer.

DISCUSSION

OA is mandated in many cases of SCIAS such as the risk of abdominal compartment syndrome associated with closure, or a planned second look as for example part of "damage control"; however, improved source control (locally and systemically) is the most uncertain indication for an OA. The COOL trial seeks to expand potential sites and proceed with the evaluation of NPPT agnostic to device, to properly examine the hypothesis that this treatment attenuates systemic damage and improves survival. This approach will not affect internal validity and should improve the external validity of any observed results of the intervention.

TRIAL REGISTRATION

National Institutes of Health ( https://clinicaltrials.gov/ct2/show/NCT03163095 ).

Patients with an Open Abdomen in Asian, American and European Continents: A Comparative Analysis from the International Register of Open Abdomen (IROA)

BACKGROUND

International register of open abdomen (IROA) enrolls patients from several centers in American, European, and Asiatic continent. The aim of our study is to compare the characteristics, management and clinical outcome of adult patients treated with OA in the three continents.

MATERIAL AND METHODS

A prospective analysis of adult patients enrolled in the international register of open abdomen (IROA).

TRIAL REGISTRATION

NCT02382770.

RESULTS

1183 patients were enrolled from American, European and Asiatic Continent. Median age was 63 years (IQR 49-74) and was higher in the European continent (65 years, p < 0.001); 57% were male. The main indication for OA was peritonitis (50.6%) followed by trauma (15.4%) and vascular emergency (13.5%) with differences among the continents (p < 0.001). Commercial NPWT was preferred in America and Europe (77.4% and 52.3% of cases) while Barker vacuum pack (48.2%) was the preferred temporary abdominal closure technique in Asia (p < 0.001). Definitive abdominal closure was achieved in 82.3% of cases in America (fascial closure in 90.2% of cases) and in 56.4% of cases in Asia (p < 0.001). Prosthesis were mostly used in Europe (17.3%, p < 0.001). The overall entero-atmospheric fistula rate 2.5%. Median open abdomen duration was 4 days (IQR 2-7). The overall intensive care unit and hospital length-of-stay were, respectively, 8 and 11 days (no differences between continents). The overall morbidity and mortality rates for America, Europe, and Asia were, respectively, 75.8%, 75.3%, 91.8% (p = 0.001) and 31.9%, 51.6%, 56.9% (p < 0.001).

CONCLUSION

There is no uniformity in OA management in the different continents. Heterogeneous adherence to international guidelines application is evident. Different temporary abdominal closure techniques in relation to indications led to different outcomes across the continents. Adherence to guidelines, combined with more consistent data, will ultimately allow to improving knowledge and outcome.

Vacuum assisted closure for defects of the abdominal wall after intestinal transplantation

BACKGROUND

Isolated intestinal transplantation (IT) is indicated in cases of intestinal failure (IF) in the absence of severe liver dysfunction. Short bowel syndrome (SBS) is the most frequent IF etiology, and due to the absence or considerable reduction of intestinal loops in the abdominal cavity in these patients, there is atrophy and muscle retraction of the abdominal wall, leading to loss of the abdominal domain and elasticity and preventing the primary closure of the abdominal wall. This study aimed to describe a technique for the closure of the abdominal wall after IT without using prostheses.

METHODS

Four patients underwent IT with the impossibility of primary closure of the abdominal wall. We describe a novel technique, associating a series of vacuum-assisted closure dressings, components separation, and relaxation incisions.

RESULTS

All patients presented a successful closure of the abdominal wall with the described technique, with no complications related to the abdominal wall.

CONCLUSION

The technique proved to be safe, effective, and reproducible as an option for abdominal wall closure after IT. Employing this technique in a greater number of cases is necessary to confirm these results.

Protective ventilation in a pig model of acute lung injury: timing is as important as pressure

Ventilator-induced lung injury (VILI) is a significant risk for patients with acute respiratory distress syndrome (ARDS). Management of the patient with ARDS is currently dominated by the use of low tidal volume mechanical ventilation, the presumption being that this mitigates overdistension (OD) injury to the remaining normal lung tissue. Evidence exists, however, that it may be more important to avoid cyclic recruitment and derecruitment (RD) of lung units, although the relative roles of OD and RD in VILI remain unclear. Forty pigs had a heterogeneous lung injury induced by Tween instillation and were randomized into four groups (n = 10 each) with higher (↑) or lower (↓) levels of OD and/or RD imposed using airway pressure release ventilation (APRV). OD was increased by setting inspiratory airway pressure to 40 cmH2O and lessened with 28 cmH2O. RD was attenuated using a short duration of expiration (∼0.45 s) and increased with a longer duration (∼1.0 s). All groups developed mild ARDS following injury. RD ↑ OD↑ caused the greatest degree of lung injury as determined by [Formula: see text]/[Formula: see text] ratio (226.1 ± 41.4 mmHg). RD ↑ OD↓ ([Formula: see text]/[Formula: see text]= 333.9 ± 33.1 mmHg) and RD ↓ OD↑ ([Formula: see text]/[Formula: see text] = 377.4 ± 43.2 mmHg) were both moderately injurious, whereas RD ↓ OD↓ ([Formula: see text]/[Formula: see text] = 472.3 ± 22.2 mmHg; P < 0.05) was least injurious. Both tidal volume and driving pressure were essentially identical in the RD ↑ OD↓ and RD ↓ OD↑ groups. We, therefore, conclude that considerations of expiratory time may be at least as important as pressure for safely ventilating the injured lung.NEW & NOTEWORTHY In a large animal model of ARDS, recruitment/derecruitment caused greater VILI than overdistension, whereas both mechanisms together caused severe lung damage. These findings suggest that eliminating cyclic recruitment and derecruitment during mechanical ventilation should be a preeminent management goal for the patient with ARDS. The airway pressure release ventilation (APRV) mode of mechanical ventilation can achieve this if delivered with an expiratory duration (TLow) that is brief enough to prevent derecruitment at end expiration.

Negative Pressure Wound Therapy Promotes Wound Healing by Inhibiting Inflammation in Diabetic Foot Wounds: A Role for NOD1 Receptor

Aims: Diabetic foot results in frequent amputation and quality-of-life reduction in diabetes population. These lesions are featured by a prolonged and exaggerated inflammation with a significant impairment in local bacterial invasion. Negative pressure wound therapy (NPWT) attenuates hyperinflammation in the healing of diabetic foot wounds, but the potential mechanism of NPWT down-regulated inflammatory reaction still remains elusive. This study aims to explore the inflammatory signaling involved in the effect of NPWT on diabetic ulcer. Methods: Thirty patients with diabetic foot ulceration were divided into NPWT group (treated with NPWT, n = 10), NPWT + FK565 group (treated with NPWT combined with FK565 which is NOD1 receptor ligand, n = 10) and control group (n = 10). After two weeks treatment, samples were harvested and analyzed by histochemistry for infiltration of inflammatory cells, immunofluorescence stain for NOD1, western blotting for NOD1, RIP2 (Receptor interacting protein 2), IL-1β, TAK1 (Transforming growth factor-β-activated kinase1), p65 and real time-PCR for expression of NOD1 and RIP2. Results: NPWT could notably accelerate the diabetic wound healing through alleviating inflammatory reaction. The immunofluorescence analysis results revealed that NOD1 was mainly expressed in the cytoplasm and noticeably decreased after the NPWT treatment. And NPWT obviously decreased both the mRNA and protein level of NOD1 and RIP2. Moreover, The protein expression of IL-1β, TAK1 and p65 in the NPWT-group were significant decreased. Conclusion: NPWT effectively promotes wound healing by suppressing the wound inflammation in diabetic foot, which is mediated at least in part by suppression of NOD1 receptor.

Damage-control surgery in patients with nontraumatic abdominal emergencies: A systematic review and meta-analysis

BACKGROUND

After the successful implementation in trauma, damage-control surgery (DCS) is being increasingly used in patients with nontraumatic emergencies. However, the role of DCS in the nontrauma setting is not well defined. The aim of this study was to investigate the effect of DCS on mortality in patients with nontraumatic abdominal emergencies.

METHODS

Systematic literature search was done using PubMed. Original articles addressing nontrauma DCS were included. Two meta-analyses were performed, comparing (1) mortality in patients undergoing nontrauma DCS versus conventional surgery (CS) and (2) the observed versus expected mortality rate in the DCS group. Expected mortality was derived from Acute Physiology And Chronic Health Evaluation, Simplified Acute Physiology Score, and Portsmouth Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity scores.

RESULTS

A total of five nonrandomized prospective and 16 retrospective studies were included. Nontrauma DCS was performed in 1,238 and nontrauma CS in 936 patients. Frequent indications for surgery in the DCS group were (weighted proportions) hollow viscus perforation (28.5%), mesenteric ischemia (26.5%), anastomotic leak and postoperative peritonitis (19.6%), nontraumatic hemorrhage (18.4%), abdominal compartment syndrome (17.8%), bowel obstruction (15.5%), and pancreatitis (12.9%). In meta-analysis 1, including eight studies, mortality was not significantly different between the nontrauma DCS and CS group (risk difference, 0.09; 95% confidence interval, -0.06 to 0.24). Meta-analysis 2, including 14 studies, revealed a significantly lower observed than expected mortality rate in patients undergoing nontrauma DCS (risk difference, -0.18; 95% confidence interval, -0.29 to -0.06).

CONCLUSION

This meta-analysis revealed no significantly different mortality in patients undergoing nontrauma DCS versus CS. However, observed mortality was significantly lower than the expected mortality rate in the DCS group, suggesting a benefit of the DCS approach. Based on these two findings, the effect of DCS on mortality in patients with nontraumatic abdominal emergencies remains unclear. Further prospective investigation into this topic is warranted.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

Vacuum-assisted closure versus on-demand relaparotomy in patients with secondary peritonitis-the VACOR trial: protocol for a randomised controlled trial

BACKGROUND

Secondary peritonitis is a severe condition with a 20-32% reported mortality. The accepted treatment modalities are vacuum-assisted closure (VAC) or primary closure with relaparotomy on-demand (ROD). However, no randomised controlled trial has been completed to compare the two methods potential benefits and disadvantages.

METHODS

This study will be a randomised controlled multicentre trial, including patients aged 18 years or older with purulent or faecal peritonitis confined to at least two of the four abdominal quadrants originating from the small intestine, colon, or rectum. Randomisation will be web-based to either primary closure with ROD or VAC in blocks of 2, 4, and 6. The primary endpoint is peritonitis-related complications within 30 or 90 days and one year after index operation. Secondary outcomes are comprehensive complication index (CCI) and mortality after 30 or 90 days and one year; quality of life assessment by (SF-36) after three and 12 months, the development of incisional hernia after 12 months assessed by clinical examination and CT-scanning and healthcare resource utilisation. With an estimated superiority of 15% in the primary outcome for VAC, 340 patients must be included. Hospitals in Denmark and Europe will be invited to participate.

DISCUSSION

There is no robust evidence for choosing either open abdomen with VAC treatment or primary closure with relaparotomy on-demand in patients with secondary peritonitis. The present study has the potential to answer this important clinical question.

TRIAL REGISTRATION

The study protocol has been registered at clinicaltrials.gov (NCT03932461). Protocol version 1.0, 9 January 2022.

Difference between delayed anastomosis and early anastomosis in damage control laparotomy affecting the infusion volume and NPWT output volume: is infusion restriction necessary in delayed anastomosis? A single-center retrospective analysis

Objectives

During temporary abdominal closure (TAC) with damage control laparotomy (DCL), infusion volume and negative-pressure wound therapy (NPWT) output volume are associated with the success and prognosis of primary fascial closure. The same may also hold true for anastomosis. The aim of this research is to evaluate whether the difference between early anastomosis and delayed anastomosis in DCL is related to infusion volume and NPWT output volume.

Methods

This single-center retrospective analysis targeted patients managed with TAC during emergency surgery for trauma or intra-abdominal sepsis between January 2011 and December 2019. It included patients who underwent repair/anastomosis/colostomy in the first surgery and patients who underwent intestinal resection in the first surgery followed by delayed anastomosis with no intestinal continuity.

Results

Seventy-three patients were managed with TAC using NPWT, including 19 cases of repair, 17 of colostomy, and 37 of anastomosis. In 16 patients (trauma 5, sepsis 11) with early anastomosis and 21 patients (trauma 16, sepsis 5) with delayed anastomosis, there was no difference in the infusion volume (p=0.2318) or NPWT output volume (p=0.7128) 48 hours after surgery. Additionally, there was no difference in the occurrence of suture failure (p=0.8428). During the second-look surgery after 48 hours, the anastomosis was further postponed for 48% of the patients who underwent delayed anastomosis. There was no difference in the infusion volume (p=0.0783) up to the second-look surgery between the patients whose delayed anastomosis was postponed and those who underwent delayed anastomosis, but there was a tendency toward a large NPWT output volume (p=0.024) in the postponed delayed anastomosis group.

Conclusion

Delayed anastomosis may be managed with the same infusion volume as that used for early anastomosis. There is also the option of postponing anastomosis if the planned delayed anastomosis is complicated.

Level of evidence

Therapeutic/Care Management, Level IV.

Acute mesenteric ischemia and small bowel imaging findings in COVID-19: A comprehensive review of the literature

BACKGROUND

Coronavirus disease 2019 (COVID-19), an infectious condition caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread worldwide since its first description in Wuhan in December 2019. Even though respiratory manifestations are the most prevalent and responsible for disease morbidity and mortality, extrapulmonary involvement has progressively gained relevance. In particular, gastrointestinal (GI) signs and symptoms, reported in up to two-thirds of patients with COVID-19, might represent the first and, in some cases, the only disease presentation. Their presence has been associated in some studies with an increased risk of a severe disease course. Proposed pathogenic mechanisms explaining GI tract involvement are either direct viral access to intestinal cells via angiotensin-converting enzyme 2 or indirect damage of the intestinal wall through mesenteric ischemia induced by the hypercoagulable state associated with COVID-19 infection. Although not typical of SARS-CoV-2 infection, several small bowel manifestations have been described in infected patients who underwent any form of abdominal imaging. The radiological findings were mainly reported in patients with abdominal symptoms, among which abdominal pain was the most common.

AIM

To discuss small bowel radiological manifestations of SARS-CoV-2 infection in abdominal imaging studies.

METHODS

Bibliographical searches were performed in PubMed, using the following keywords: "COVID-19" AND "imaging" AND "gastrointestinal" OR "abdominal" OR "small bowel".

RESULTS

Of 62 patients with described radiologic small bowel alterations, mesenteric ischemia was diagnosed in 31 cases (50%), small bowel wall thickening in 10 cases (16%), pneumatosis in nine cases (15%), intussusception in eight cases (13%), pneumoperitoneum in two cases (3%) and paralytic ileus in two cases (3%). We also reported mesenteric adipose tissue hypertrophy and lymph nodes enlargement in a young woman.

CONCLUSION

So far it is difficult to establish whether these manifestations are the direct consequence of SARS-CoV-2 infection or collateral findings in infected patients, but their recognition would be pivotal to set a closer follow-up and to reduce missed diagnoses.

Large animal models for translational research in acute kidney injury

While extensive research using animal models has improved the understanding of acute kidney injury (AKI), this knowledge has not been translated into effective treatments. Many promising interventions for AKI identified in mice and rats have not been validated in subsequent clinical trials. As a result, the mortality rate of AKI patients remains high. Inflammation plays a fundamental role in the pathogenesis of AKI, and one reason for the failure to translate promising therapeutics may lie in the profound difference between the immune systems of rodents and humans. The immune systems of large animals such as swine, nonhuman primates, sheep, dogs and cats, more closely resemble the human immune system. Therefore, in the absence of a basic understanding of the pathophysiology of human AKI, large animals are attractive models to test novel interventions. However, there is a lack of reviews on large animal models for AKI in the literature. In this review, we will first highlight differences in innate and adaptive immunities among rodents, large animals, and humans in relation to AKI. After illustrating the potential merits of large animals in testing therapies for AKI, we will summarize the current state of the evidence in terms of what therapeutics have been tested in large animal models. The aim of this review is not to suggest that murine models are not valid to study AKI. Instead, our objective is to demonstrate that large animal models can serve as valuable and complementary tools in translating potential therapeutics into clinical practice.

Should Negative Pressure Therapy Replace Any Other Temporary Abdominal Closure Device in Open-Abdomen Management of Secondary Peritonitis?

AIM

To clarify the advantages of negative pressure therapy (NPT) compared to other methods of temporary abdominal closure (TAC) in the management of secondary peritonitis.

METHODS

We retraced the history of known methods of TAC, and analyzed their advantages and disadvantages. We evaluated as the NPT mechanisms, both from the macroscopic that bio-molecular point of view, well suits to manage this difficult condition.

RESULTS

The ideal TAC technique should be quick to apply, easy to change, protect and contain the abdominal viscera, decrease bowel edema, prevent loss of domain and abdominal compartment syndrome, limit contamination, allow egress of peritoneal fluid (and its estimation) and not result in adhesions. It should also be cost-effective, minimize the number of dressing changes and the number of surgical revisions, and ensure a high rate of early closure with a low rate of complications (especially entero-atmospheric fistula). For NPT, the reported fistula rate is 7%, primary fascial closure ranges from 33 to 100% (average 60%) and the mortality rate is about 20%. With the use of NPT as TAC, it may be possible to extend the window of time to achieve primary fascial closure (for up to 20-40 days).

CONCLUSION

NPT has several potential advantages in open-abdomen (OA) management of secondary peritonitis and may make it possible to achieve all the goals suggested above for an ideal TAC system. Only trained staff should use NPT, following the manufacturer's instructions when commercial products are used. Even if there was a significant evolution in OA management, we believe that further research into the role of NPT for secondary peritonitis is necessary.

Effects of negative-pressure therapy with and without ropivacaine instillation in the early evolution of severe peritonitis in pigs

PURPOSE

The abdomen is the second most common source of sepsis and secondary peritonitis, which likely lead to death. In the present study, we hypothesized that instillation of local anesthetics into the peritoneum might mitigate the systemic inflammatory response syndrome (SIRS) in the open abdomen when combined with negative-pressure therapy (NPT) to treat severe peritonitis.

METHODS

We performed a study in 21 pigs applying a model of sepsis based on ischemia/reperfusion and fecal spread into the peritoneum. The pigs were randomized into three groups, and treated for 6 h as follows: Group A: temporary abdominal closure with ABTHERA™ Open Abdomen Negative-Pressure Therapy; Group B: temporary abdominal closure with ABTHERA™ Open Abdomen Negative-Pressure Therapy plus abdominal instillation with physiological saline solution (PSS); and Group C: temporary abdominal closure with ABTHERA™ Open Abdomen Negative-Pressure Therapy plus peritoneal instillation with a solution of ropivacaine in PPS.

RESULTS

A comparison between the three groups revealed no statistically significant difference for any of the parameters registered (p > 0.05), i.e., intra-abdominal pressure, blood pressure, heart rate, O2 saturation, diuresis, body temperature, and blood levels of interleukin 6 (IL-6), tumor necrosis factor alpha (TNFα), and c-reactive protein (CRP). In addition, histological studies of the liver, ileum, kidney and lung showed no difference between groups.

CONCLUSIONS

The use of abdominal instillation (with or without ropivacaine) did not change the effect of 6 h of NPT after sepsis in animals with open abdomen. The absence of adverse effects suggests that longer treatments should be tested.

Small Immunomodulatory Molecules as Potential Therapeutics in Experimental Murine Models of Acute Lung Injury (ALI)/Acute Respiratory Distress Syndrome (ARDS)

Background: Acute lung injury (ALI) or its most advanced form, acute respiratory distress syndrome (ARDS) is a severe inflammatory pulmonary process triggered by a variety of insults including sepsis, viral or bacterial pneumonia, and mechanical ventilator-induced trauma. Currently, there are no effective therapies available for ARDS. We have recently reported that a novel small molecule AVR-25 derived from chitin molecule (a long-chain polymer of N-acetylglucosamine) showed anti-inflammatory effects in the lungs. The goal of this study was to determine the efficacy of two chitin-derived compounds, AVR-25 and AVR-48, in multiple mouse models of ALI/ARDS. We further determined the safety and pharmacokinetic (PK) profile of the lead compound AVR-48 in rats. Methods: ALI in mice was induced by intratracheal instillation of a single dose of lipopolysaccharide (LPS; 100 µg) for 24 h or exposed to hyperoxia (100% oxygen) for 48 h or undergoing cecal ligation and puncture (CLP) procedure and observation for 10 days. Results: Both chitin derivatives, AVR-25 and AVR-48, showed decreased neutrophil recruitment and reduced inflammation in the lungs of ALI mice. Further, AVR-25 and AVR-48 mediated diminished lung inflammation was associated with reduced expression of lung adhesion molecules with improvement in pulmonary endothelial barrier function, pulmonary edema, and lung injury. Consistent with these results, CLP-induced sepsis mice treated with AVR-48 showed a significant increase in survival of the mice (80%) and improved lung histopathology in the treated CLP group. AVR-48, the lead chitin derivative compound, demonstrated a good safety profile. Conclusion: Both AVR-25 and AVR-48 demonstrate the potential to be developed as therapeutic agents to treat ALI/ARDS.

[Laparostoma-Avoidance and treatment of complications]

The open abdomen (OA) is an established concept for treating severe abdominal diseases. The most frequent reasons for placement of an open abdomen are abdominal sepsis (e.g. from intestinal perforation or anastomotic leakage), severe abdominal organ injury and abdominal compartment syndrome. The pathophysiology is much more complex than the surgeon's eye can see in an OA. The temporary closure of the abdominal wall ensures sufficient drainage of infected ascites, protection of the intestinal loops and conditioning of the abdominal wall in order to be able carry out definitive closure of the abdominal wall at the end of the surgical treatment. Negative peritoneal pressure therapy combined with fascia traction (with or without mesh) is well-established in the management of an open abdomen.

Cytokine clearance in serum and peritoneal fluid of patients undergoing damage control surgery with abdominal negative pressure therapy for abdominal sepsis

Objectives

Open abdomen technique with negative pressure therapy (NPT) is widely used in patients with severe abdominal sepsis. The aim of this study was to evaluate cytokine clearance in serum and peritoneal fluid during NPT.

Methods

This prospective pilot study included six patients with severe abdominal sepsis requiring discontinuity resection and NPT for 48 h followed by planned reoperation. Cytokines (IL6, IL8, IL10, TNFalpha, and IL1beta) were measured in the serum and peritoneal fluid during index operation, on postoperative days 0, 1, and 2.

Results

Concentrations of cytokines in peritoneal fluid were higher than in serum. IL10 showed a clearance both in serum (to 16.6%, p=0.019) and peritoneal fluid (to 40.9%, p=0.014). IL6 cleared only in serum (to 24.7%, p=0.001) with persistently high levels in peritoneal fluid. IL8 remained high in both serum and peritoneal fluid. TNFalpha and IL1beta were both low in serum with wide range of high peritoneal concentrations. Only TNFalpha in peritoneal fluid showed significant differences between patients with ischemia vs. perforation (p=0.006).

Conclusions

The present pilot study suggests that cytokines display distinct patterns of clearance or persistence in the peritoneal fluid and serum over the first 48 h of treatment in severe abdominal sepsis with NPT.

Do we have the guts to go? The abdominal compartment, intra-abdominal hypertension, the human microbiome and exploration class space missions

Humans are destined to explore space, yet critical illness and injury may be catastrophically limiting for extraterrestrial travel. Humans are superorganisms living in symbiosis with their microbiomes, whose genetic diversity dwarfs that of humans. Symbiosis is critical and imbalances are associated with disease, occurring within hours of serious illness and injury. There are many characteristics of space flight that negatively influence the microbiome, especially deep space itself, with its increased radiation and absence of gravity. Prolonged weightlessness causes many physiologic changes that are detrimental; some resemble aging and will adversely affect the ability to tolerate critical illness or injury and subsequent treatment. Critical illness-induced intra-abdominal hypertension (IAH) may induce malperfusion of both the viscera and microbiome, with potentially catastrophic effects. Evidence from animal models confirms profound IAH effects on the gut, namely ischemia and disruption of barrier function, mechanistically linking IAH to resultant organ dysfunction. Therefore, a pathologic dysbiome, space-induced immune dysfunction and a diminished cardiorespiratory reserve with exacerbated susceptibility to IAH, imply that a space-deconditioned astronaut will be vulnerable to IAH-induced gut malperfusion. This sets the stage for severe gut ischemia and massive biomediator generation in an astronaut with reduced cardiorespiratory/immunological capacity. Fortunately, experiments in weightless analogue environments suggest that IAH may be ameliorated by conformational abdominal wall changes and a resetting of thoracoabdominal mechanics. Thus, review of the interactions of physiologic changes with prolonged weightlessness and IAH is required to identify appropriate questions for planning exploration class space surgical care.

Intra-abdominal Hypertension and the Open Abdomen: Nursing Guidelines From the Abdominal Compartment Society

Intra-abdominal hypertension has been identified as an independent risk factor for death in critically ill patients. Known risk factors for intra-abdominal hypertension indicate that intra-abdominal pressures should be measured and monitored. The Abdominal Compartment Society has identified medical and surgical interventions to relieve intra-abdominal hypertension or to manage the open abdomen if abdominal compartment syndrome occurs. The purpose of this article is to describe assessments and interventions for managing intra-abdominal hypertension and open abdomen that are within the scope of practice for direct-care nurses. These guidelines provide direction to critical care nurses caring for these patients.

Protective Effect of Metformin, Resveratrol and Alpha-lipoic Acid on Radiation- Induced Pneumonitis and Fibrosis: A Histopathological Study

BACKGROUND

Radiation-induced pneumonitis and fibrosis are the most common side effects of chest radiotherapy. They result from massive and chronic production of Reactive Oxygen Species (ROS), inhibition of antioxidant enzymes as well as the release of several inflammatory mediators. In this study, we aimed to detect the radioprotective effects of metformin (as inhibitor of mitochondrial ROS), resveratrol (as stimulator of antioxidant defense enzymes) and alpha-lipoic acid (as direct antioxidant) for alleviating radiation-induced pneumonitis and fibrosis.

METHODS

80 Male Mice were randomly allotted to eight groups which include G1: control; G2: resveratrol; G3: alpha-lipoic acid; G4: metformin; G5: radiation; G6: radiation plus resveratrol; G7: radiation plus alpha-lipoic acid; G8: radiation plus metformin. Drugs' doses were as follows: 100 mg/kg metformin, 200 mg/kg resveratrol and 200 mg/kg alpha-lipoic acid. Irradiation with a single radiation dose of 18 Gy was performed using a cobalt-60 (60Co) gamma-ray source. After 80 days, all mice were sacrificed and their lung tissues evaluated for morphological changes using histopathological markers.

RESULTS

Irradiation led to acute pneumonitis including infiltration of inflammatory cells and damages to alveolar and vascular, as well as mild fibrosis. Metformin, alpha-lipoic acid and resveratrol were able to reduce pneumonitis and overcome radiation-induced fibrosis.

CONCLUSION

All agents could protect against radiation-induced lung injury moderately. It is possible that administering higher doses of these drugs over a long period of time could give better radioprotection of the lung.

The Bucharest ESTES consensus statement on peritonitis

INTRODUCTION

Peritonitis is still an important health problem associated with high morbidity and mortality. A multidisciplinary approach to the management of patients with peritonitis may be an important factor to reduce the risks for patients and improve efficiency, outcome, and the cost of care.

METHODS

Expert panel discussion on Peritonitis was held in Bucharest on May 2017, during the 17th ECTES Congress, involving surgeons, infectious disease specialists, radiologists and intensivists with the goal of defining recommendations for the optimal management of peritonitis.

CONCLUSION

This document is an updated presentation of management of peritonitis and represents the summary of the final recommendations approved by a panel of experts.

Protocol for a parallel economic evaluation of a trial comparing two surgical strategies in severe complicated intra-abdominal sepsis: the COOL-cost study

BACKGROUND

The risk of death in severe complicated intra-abdominal sepsis (SCIAS) remains high despite decades of surgical and antimicrobial research. New management strategies are required to improve outcomes. The Closed Or Open after Laparotomy (COOL) trial investigates an open-abdomen (OA) approach with active negative pressure peritoneal therapy. This therapy is hypothesized to better manage peritoneal bacterial contamination, drain inflammatory ascites, and reduce the risk of intra-abdominal hypertension leading to improved survival and decreased complications. The total costs and cost-effectiveness of this therapy (as compared with standard fascial closure) are unknown.

METHODS

We propose a parallel cost-utility analysis of this intervention to be conducted alongside the 1-year trial, extrapolating beyond that using decision analysis. Using resource use metrics (e.g., length of stay, re-admissions) from patients at all study sites and microcosting data from patients enrolled in Calgary, Alberta, the mean cost difference between treatment arms will be established from a publicly-funded health care payer perspective. Quality of life will be measured at 6 months and 1 year postoperatively with the Euroqol EQ-5D-5 L and SF-36 surveys. A within-trial analysis will establish cost and utility at 1 year, using a bootstrapping approach to provide confidence intervals around an estimated incremental cost-effectiveness ratio. If neither operative strategy is economically dominant, Markov modeling will be used to extrapolate the cost per quality-adjusted life years gained to 2-, 5-, 10-year, and lifetime horizons. Future costs and benefits will be discounted at 1.5% per annum. A cost-effectiveness acceptability curve will be generated using Monte Carlo simulation. If all trial outcomes are similar, the primary analysis will default to a cost-minimization approach. Subgroup analysis will be carried out for patients with and without septic shock at presentation, and for patients whose initial APACHE II scores are > 20 versus ≤ 20.

DISCUSSION

In addition to an estimate of the clinical effectiveness of an OA approach for SCIAS, an understanding of its cost effectiveness will be required prior to its adoption in any resource-constrained environment. We will estimate this key parameter for use by clinicians and policymakers.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03163095, registered May 22, 2017.

Abdominal compartment syndrome: Often overlooked conditions in medical intensive care units

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome are well recognized entities among surgical patients. Nevertheless, a number of prospective and retrospective observational studies have shown that IAH is prevalent in about half of the critically ill patients in the medical intensive care units (ICU) and has been widely recognized as an independent risk factor for mortality. It is alarming to note that many members of the critical care team in medical ICU are not aware of the consequences of untreated IAH and the delay in making the diagnosis leads to increased morbidity and mortality. Frequently it is underdiagnosed and undertreated in this patient population. Elevated intra-abdominal pressure decreases the blood flow to the kidneys and other abdominal viscera and also results in reduced cardiac output and difficulties in ventilating the patient because of increased intrathoracic pressure. When intraabdominal hypertension is not promptly recognized and treated, it leads to abdominal compartment syndrome, multiorgan dysfunction syndrome and death. Large volume fluid resuscitation is very common in medical ICU patients presenting with sepsis, shock and other inflammatory conditions like pancreatitis and it is one of the major risk factors for the development of intra-abdominal hypertension. This article presents an overview of the epidemiology, definitions, risk factors, pathophysiology and management of IAH and abdominal compartment syndrome in critically ill medical ICU patients.

Abdominal Compartment Syndrome: Improving Outcomes With A Multidisciplinary Approach - A Narrative Review

Abdominal compartment syndrome (ACS) refers to a severe increase in intra-abdominal pressure associated with single or multiorgan failure. ACS with specific pathophysiological processes and detrimental outcomes may occur in a variety of clinical conditions. Patients with ACS are predominantly managed in critical care settings, however, a wide range of multidisciplinary interventions are frequently required from medical, surgical, radiological and nursing specialties. The medical management, aiming to prevent the progression of intra-abdominal hypertension to ACS, is extensively reviewed. Timing and techniques of surgical decompression techniques, as well as management of open abdomen, are outlined. In summary, the current narrative review provides data on history, definitions, epidemiology and pathophysiology of the syndrome and highlights the importance of multidisciplinary approach in the management of ACS in adults.

A histological analysis of chronic wounds treated with negative pressure wound therapy to aid healing: a case series

OBJECTIVE

Our aim was to examine histopathological changes in three chronic wounds, and to assess whether the application of negative pressure wound therapy (NPWT) changes the wound bed environment.

METHOD

- Results: We recruited three patients were recruited who had a non-healing wounds in excess of eight weeks. Histopathological changes in the wound bed supported the evidence that NPWT changes the wound bed environment by reducing inflammatory damage and facilitating wound bed perfusion with angiogenesis.

CONCLUSION

We suggest that NPWT is a valuable adjunct to aid chronic wound healing. In this case series, we observed histopathological changes and improvement in the wounds, following one week's treatment with NPWT. Further analysis should be done to demonstrate any interaction between the cells involved in the wound healing process is enhanced, growth factor performance is optimised and cell migration is achieved following NPWT, in order to facilitate the healing process.

Ethical considerations in conducting surgical research in severe complicated intra-abdominal sepsis

BACKGROUND

Severe complicated intra-abdominal sepsis (SCIAS) has high mortality, thought due in part to progressive bio-mediator generation, systemic inflammation, and multiple organ failure. Treatment includes early antibiotics and operative source control. At surgery, open abdomen management with negative-peritoneal-pressure therapy (NPPT) has been hypothesized to mitigate MOF and death, although clinical equipoise for this operative approach exists. The Closed or Open after Laparotomy (COOL) study (https://clinicaltrials.gov/ct2/show/NCT03163095) will prospectively randomize eligible patients intra-operatively to formal abdominal closure or OA with NPTT. We review the ethical basis for conducting research in SCIAS.

MAIN BODY

Research in critically ill incapacitated patients is important to advance care. Conducting research among SCIAS is complicated due to the severity of illness including delirium, need for emergent interventions, diagnostic criteria confirmed only at laparotomy, and obtundation from anaesthesia. In other circumstances involving critically ill patients, clinical experts have worked closely with ethicists to apply principles that balance the rights of patients whilst simultaneously permitting inclusion in research. In Canada, the Tri-Council Policy Statement-2 (TCPS-2) describes six criteria that permit study enrollment and randomization in such situations: (a) serious threat to the prospective participant requires immediate intervention; (b) either no standard efficacious care exists or the research offers realistic possibility of direct benefit; (c) risks are not greater than that involved in standard care or are clearly justified by prospect for direct benefits; (d) prospective participant is unconscious or lacks capacity to understand the complexities of the research; (e) third-party authorization cannot be secured in sufficient time; and (f) no relevant prior directives are known to exist that preclude participation. TCPS-2 criteria are in principle not dissimilar to other (inter)national criteria. The COOL study will use waiver of consent to initiate enrollment and randomization, followed by surrogate or proxy consent, and finally delayed informed consent in subjects that survive and regain capacity.

CONCLUSIONS

A delayed consent mechanism is a practical and ethical solution to challenges in research in SCIAS. The ultimate goal of consent is to balance respect for patient participants and to permit participation in new trials with a reasonable opportunity for improved outcome and minimal risk of harm.

EWMA Document: Negative Pressure Wound Therapy

1. Introduction Since its introduction in clinical practice in the early 1990's negative pressure wounds therapy (NPWT) has become widely used in the management of complex wounds in both inpatient and outpatient care.¹ NPWT has been described as a effective treatment for wounds of many different aetiologies^2,3 and suggested as a gold standard for treatment of wounds such as open abdominal wounds,^4-6 dehisced sternal wounds following cardiac surgery^7,8 and as a valuable agent in complex non-healing wounds.^9,10 Increasingly, NPWT is being applied in the primary and home-care setting, where it is described as having the potential to improve the efficacy of wound management and help reduce the reliance on hospital-based care.¹¹ While the potential of NPWT is promising and the clinical use of the treatment is widespread, highlevel evidence of its effectiveness and economic benefits remain sparse.^12-14 The ongoing controversy regarding high-level evidence in wound care in general is well known. There is a consensus that clinical practice should be evidence-based, which can be difficult to achieve due to confusion about the value of the various approaches to wound management; however, we have to rely on the best available evidence. The need to review wound strategies and treatments in order to reduce the burden of care in an efficient way is urgent. If patients at risk of delayed wound healing are identified earlier and aggressive interventions are taken before the wound deteriorates and complications occur, both patient morbidity and health-care costs can be significantly reduced. There is further a fundamental confusion over the best way to evaluate the effectiveness of interventions in this complex patient population. This is illustrated by reviews of the value of various treatment strategies for non-healing wounds, which have highlighted methodological inconsistencies in primary research. This situation is confounded by differences in the advice given by regulatory and reimbursement bodies in various countries regarding both study design and the ways in which results are interpreted. In response to this confusion, the European Wound Management Association (EWMA) has been publishing a number of interdisciplinary documents^15-19 with the intention of highlighting: The nature and extent of the problem for wound management: from the clinical perspective as well as that of care givers and the patients Evidence-based practice as an integration of clinical expertise with the best available clinical evidence from systematic research The nature and extent of the problem for wound management: from the policy maker and healthcare system perspectives The controversy regarding the value of various approaches to wound management and care is illustrated by the case of NPWT, synonymous with topical negative pressure or vacuum therapy and cited as branded VAC (vacuum-assisted closure) therapy. This is a mode of therapy used to encourage wound healing. It is used as a primary treatment of chronic wounds, in complex acute wounds and as an adjunct for temporary closure and wound bed preparation preceding surgical procedures such as skin grafts and flap surgery. Aim An increasing number of papers on the effect of NPWT are being published. However, due to the low evidence level the treatment remains controversial from the policy maker and health-care system's points of view-particularly with regard to evidence-based medicine. In response EWMA has established an interdisciplinary working group to describe the present knowledge with regard to NPWT and provide overview of its implications for organisation of care, documentation, communication, patient safety, and health economic aspects. These goals will be achieved by the following: Present the rational and scientific support for each delivered statement Uncover controversies and issues related to the use of NPWT in wound management Implications of implementing NPWT as a treatment strategy in the health-care system Provide information and offer perspectives of NPWT from the viewpoints of health-care staff, policy makers, politicians, industry, patients and hospital administrators who are indirectly or directly involved in wound management.

The HO-1-expressing bone mesenchymal stem cells protects intestine from ischemia and reperfusion injury

BACKGROUND

Bone mesenchymal stromal cells (BMSC) showed protective potential against intestinal ischemia. Oxygenase-1(HO-1) could alleviate oxidative stress. In the present study, we constructed HO-1-expressing BMSC and detected the effects of it on survival, intestinal injury and inflammation following intestinal ischemia and reperfusion injury (I/R).

METHODS

In this experiment, eighty adult male mice were divided into Sham, I/R, I/R + BMSC, I/R + BMSC/HO-1 groups. Mice were anesthetized and intestinal I/R model were established by temporarily occluding the superior mesenteric artery for 60 min with a non-crushing clamp. Following ischemia, the clamp was removed and the intestines were allowed for reperfusion. Prior to abdominal closure, BMSC/ HO-1 (2 × 10⁶ cells) or BMSC (2 × 10⁶ cells) were injected into the peritoneum of I/R mice respectively. Mice were allowed to recover for 24 h and then survival rate, intestinal injury and inflammation were determined. Reactive oxygen species (ROS) was assayed by fluorescent probe. TNFα and IL-6 were assayed by ELISA.

RESULTS

BMSC/HO-1 increased seven day survival rate, improved intestinal injury and down-regulated inflammation after intestinal I/R when compared with sole BMSC (p < 0.05 respectively). Multiple pro-inflammatory media were also decreased following application of BMSC/HO-1, when compared with sole BMSC (p < 0.05) respectively, suggesting that BMSC /HO-1 had a better protection to intestinal I/R than BMSC therapy.

CONCLUSION

Administration of BMSC/HO-1 following intestinal I/R, significantly improved intestinal I/R by limiting intestinal damage and inflammation.

Open abdominal management for perforative peritonitis with septic shock: a retrospective analysis on usefulness of a standardized treatment protocol

BACKGROUND

Damage control surgery (DCS) with open abdominal management (OAM) has been increasingly expanded to include critically ill non-trauma patients. However, there is limited data regarding the usefulness of this protocol for the treatment of severe perforative peritonitis (PP), especially with septic shock (SS). Here, we retrospectively evaluated the usefulness of our OAM protocol for PP with SS.

METHODS

We retrospectively reviewed patients with from June 2015 to September 2018. The proposed protocol was composed of the following steps: (1) rapid control of contamination; (2) temporary abdominal closure; (3) repeated washout of the abdominal cavity; and (4) delayed definitive surgery. For temporary abdominal closure, a negative pressure wound therapy device was used. The end points were the morbidity and 30-day mortality rates. Logistic backward regression was performed to identify factors associated with complications.

RESULTS

The mortality rate was 4% (1/25) and the overall morbidity rate of surviving patients was 58.3% (14/24). The mean duration of the first DCS was 67.36 ± 22.83 min. The median durations of ventilation and intensive care unit stay were 5 and 7 days, respectively. Although not significant, morbidity might be associated with age, diabetes mellitus, initial operative time, and OAM duration.

CONCLUSIONS

A standardized protocol for OAM may improve the outcomes of patients with SS due to PP. This damage control approach can be applied for the treatment of severe abdominal sepsis.

Novel Chitohexaose Analog Protects Young and Aged mice from CLP Induced Polymicrobial Sepsis

In Gram-negative bacterial sepsis, production of excess pro-inflammatory cytokines results in hyperinflammation and tissue injury. Anti-inflammatory cytokines such as IL-10 inhibit inflammation and enhance tissue healing. Here, we report a novel approach to treat septicemia associated with intra-abdominal infection in a murine model by delicately balancing pro- and anti-inflammatory cytokines. A novel oligosaccharide compound AVR-25 selectively binds to the TLR4 protein (IC₅₀ = 0.15 µM) in human peripheral blood monocytes and stimulates IL-10 production. Following the cecal ligation and puncture (CLP) procedure, intravenous dosing of AVR-25 (10 mg/kg, 6-12 h post-CLP) alone and in combination with antibiotic imipenem protected both young adult (10-12 week old) and aged (16-18 month old) mice against polymicrobial infection, organ dysfunction, and death. Proinflammatory cytokines (TNF-α, MIP-1, i-NOS) were decreased significantly and restoration of tissue damage was observed in all organs. A decrease in serum C-reactive protein (CRP) and bacterial colony forming unit (CFU) confirmed improved bacterial clearance. Together, these findings demonstrate the therapeutic ability of AVR-25 to mitigate the storm of inflammation and minimize tissue injury with high potential for adjunctive therapy in intra-abdominal sepsis.

microRNA-142-mediated repression of phosphodiesterase 3B critically regulates peripheral immune tolerance

Tregs play a fundamental role in immune tolerance via control of self-reactive effector T cells (Teffs). This function is dependent on maintenance of a high intracellular cAMP concentration. A number of microRNAs are implicated in the maintenance of Tregs. In this study, we demonstrate that peripheral immune tolerance is critically dependent on posttranscriptional repression of the cAMP-hydrolyzing enzyme phosphodiesterase-3b (Pde3b) by microRNA-142-5p (miR-142-5p). In this manner, miR-142-5p acts as an immunometabolic regulator of intracellular cAMP, controlling Treg suppressive function. Mir142 was associated with a super enhancer bound by the Treg lineage–determining transcription factor forkhead box P3 (FOXP3), and Treg-specific deletion of miR-142 in mice (Treg^Δ142) resulted in spontaneous, lethal, multisystem autoimmunity, despite preserved numbers of phenotypically normal Tregs. Pharmacological inhibition and genetic ablation of PDE3B prevented autoimmune disease and reversed the impaired suppressive function of Tregs in Treg^Δ142 animals. These findings reveal a critical molecular switch, specifying Treg function through the modulation of a highly conserved, cell-intrinsic metabolic pathway. Modulation of this pathway has direct relevance to the pathogenesis and treatment of autoimmunity and cancer.

Negative Pressure Wound Therapy with Instillation in the Septic Open Abdomen Utilizing a Modified Negative Pressure Therapy System

BACKGROUND

Various treatment modalities are utilized to treat the open abdomen. The use of negative pressure wound therapy(NPWT)has been a great advancement and has become the preferred modality for temporary abdominal closure technique (TAC). Programmed instillation of the abdominal cavity with saline solution in conjunction with a commercial negative pressure system showed positive results in the management of severe abdominal sepsis in patients that were treated with an open abdomen. Severe abdominal sepsis continues to be an oftendifficult clinical problem for the general surgeon. The use of an open abdomen technique in this setting and the ideal TAC method continue to be debated. The failure to understand the biomechanical features/limitations of negative pressure devices are often contributing factors associated with therapeutic failures reported in the literature.

OBJECTIVES

To describe the underlying principles behind negative pressure wound therapy with instillation in the context of abdominal sepsis, as well as its optimal usage in these conditions.

METHODS

A systematic review and two retrospective cohort studies, both published and unpublished performed by some of the authors were included to provide a basis form comparison between NPWT and NPWT-I outcomes in managing abdominal sepsis.

CONCLUSION

Our findings suggest that this technique appears to reduce morbidity, mortality, and hospital and critical care length of stay. This communication is intended to help inform general surgeons that manage complex abdominal infections on how to optimally apply this technique.

"Complex abdominal wall" management: evidence-based guidelines of the Italian Consensus Conference

To date, there is no shared consensus on a definition of a complex abdominal wall in elective surgery and in the emergency, on indications, technical details, complications, and follow-up. The purpose of the conference was to lay the foundations for a homogeneous approach to the complex abdominal wall with the primary intent being to attain the following objectives: (1) to develop evidence-based recommendations to define “complex abdominal wall”; (2) indications in emergency and in elective cases; (3) management of “complex abdominal wall”; (4) techniques for temporary abdominal closure. The decompressive laparostomy should be considered in a case of abdominal compartment syndrome in patients with critical conditions or after the failure of a medical treatment or less invasive methods. In the second one, beyond different mechanism, patients with surgical emergency diseases might reach the same pathophysiological end point of trauma patients where a preventive “open abdomen” might be indicated (a temporary abdominal closure: in the case of a non-infected field, the Wittmann patch and the NPWT had the best outcome followed by meshes; in the case of an infected field, NPWT techniques seem to be the preferred). The second priority is to create optimal both general as local conditions for healing: the right antimicrobial management, feeding—preferably by the enteral route—and managing correctly the open abdomen wall. The use of a mesh appears to be—if and when possible—the gold standard. There is a lot of enthusiasm about biological meshes. But the actual evidence supports their use only in contaminated or potentially contaminated fields but above all, to reduce the higher rate of recurrences, the wall anatomy and function should be restored in the midline, with or without component separation technique. On the other site has not to be neglected that the use of monofilament and macroporous non-absorbable meshes, in extraperitoneal position, in the setting of the complex abdomen with contamination, seems to have a cost effective role too. The idea of this consensus conference was mainly to try to bring order in the so copious, but not always so “evident” literature utilizing and exchanging the expertise of different specialists.

Open Abdomen in Trauma and Critical Care

The open abdomen technique and temporary abdominal closure after damage control surgery is fast becoming the standard of care for managing intra-abdominal bleeding and infectious or ischemic processes in critically ill patients. Expansion of this technique has evolved from damage control surgery in severely injured trauma patients to use in patients with abdominal compartment syndrome due to acute pancreatitis and other disorders. Subsequent therapies after use of the open abdomen technique and temporary abdominal closure are resuscitation in the intensive care unit and planned reoperation to manage the underlying cause of bleeding, infection, or ischemia. Determining the need for this potentially lifesaving intervention and managing the wound after the open abdomen has been created are all within the realm of critical care nurses. Case studies illustrate the implementation of the open abdomen technique and patient management strategies.

Impact of initial temporary abdominal closure in damage control surgery: a retrospective analysis

Background

Damage control surgery has revolutionized trauma surgery. Use of damage control surgery allows for resuscitation and reversal of coagulopathy at the risk of loss of abdominal domain and intra-abdominal complications. Temporary abdominal closure is possible with multiple techniques, the choice of which may affect ability to achieve primary fascial closure and further complication.

Methods

A retrospective analysis of all trauma patients requiring damage control laparotomy upon admission to an ACS-verified level one trauma center from 2011 to 2016 was performed. Demographic and clinical data including ability and time to attain primary fascial closure, as well as complication rates, were recorded. The primary outcome measure was ability to achieve primary fascial closure during initial hospitalization.

Results

Two hundred and thirty-nine patients met criteria for inclusion. Primary skin closure (57.7%), ABThera™ VAC system (ABT) (15.1%), Bogota bag (BB) (25.1%), or a modified Barker's vacuum-packing (BVP) (2.1%) were used in the initial laparotomy. Patients receiving skin-only closure had significantly higher rates of primary fascial closure and lower hospital mortality, but also significantly lower mean lactate, base deficit, and requirement for massive transfusion. Between ABT or BB, use of ABT was associated with increased rates of fascial closure. Multivariate regression revealed primary skin closure to be significantly associated with primary fascial closure while BB was associated with failure to achieve fascial closure.

Conclusions

Primary skin closure is a viable option in the initial management of the open abdomen, although these patients demonstrated less injury burden in our study. Use of vacuum-assisted dressings continues to be the preferred method for temporary abdominal closure in damage control surgery for trauma.