Microvascular Blood Flow Changes in the Small Intestinal Wall During Conventional Negative Pressure Wound Therapy and Negative Pressure Wound Therapy Using a Protective Disc Over the Intestines in Laparostomy

Effects of Different Pressure Levels in Topical Negative Pressure Application—Analysis of Perfusion Parameters in a Clinical Skin Model Using Multimodal Imaging Techniques

The effects of topical negative pressure therapy (TNP) have been a subject of research for many years. In this study, we investigated new imaging devices to detect clinical changes that TNP causes on healthy tissue and identified differences in microcirculation created by different pressure levels. We used near-infrared spectroscopy (NIS), thermography, and a vein illuminator to measure the differences in oxygen saturation, tissue temperature, and vein pattern. A control group (−125 mmHg) and three comparison groups with only TNP dressing (Group 1), −25 mmHg (Group 2), and −175 mmHg (Group 3) were established. Thirty minutes of TNP on intact skin was followed by 30 min of resting. A total of 24 participants were measured by all imaging devices at predetermined time points. Oxygen saturation and skin temperature increased by 8.07% and 1.67 °C for the control group, 4.00% and 1.65 °C for Group 2, and 8.45% and 1.68 °C for Group 3. Group 1 showed a slight increase in oxygen saturation and a 2.7 °C increase in skin temperature. Over the 30 min following removal of TNP, oxygen saturation and temperature decreased gradually for all groups. The vein illuminator did not show significant differences in the venous pattern or flow. Our study showed that higher negative pressure values resulted in higher oxygen saturation and higher tissue temperature.

Intra-Abdominal Pressure Monitoring During Negative Pressure Wound Therapy in the Open Abdomen

INTRODUCTION

Negative pressure wound therapy (NPWT) is commonly used in open abdomen management, where there may be a simultaneous need for prevention of abdominal hypertension, tamponade of hemorrhage, and continuous fascial tension. The regional pressure dynamics of vacuum dressings are poorly understood.

METHODS

Three duroc swine underwent mid-line laparotomy and application of vacuum open abdomen dressing, with and without sponge packing. Twenty-five catheters were placed throughout the abdomen to capture and record pressures in each quadrant as the vacuum system was ranged between (-75 mmHg to -200 mmHg pressure). Vital signs and ventilator pressures were measured and recorded concomitantly.

RESULTS

No variations in ventilatory pressures or vital signs were observed with any setting. NPWT changed pressure in seven of seventy-five catheters (9%), five of which were related to abdominal packing. When data were grouped into abdominal wall, perihepatic, perisplenic, and deep abdominal regions, there was no significant change in abdominal pressure when packing was absent. With packing, only the abdominal wall region showed a pressure change, reaching a maximum of 20% of the set vacuum pressure.

CONCLUSIONS

NPWT does only little to change the intraabdominal pressure, except in superficial locations in packed abdomens and does not appear to cause hemodynamic changes in a porcine open abdomen model. While NPWT may play an important role in fluid scavenging and fascial tensioning, there are likely to be few benefits or drawbacks specifically related to negative abdominal pressure in the deep abdomen.

The Significance of Visceral Protection in Preventing Enteroatmospheric Fistulae During Open Abdomen Treatment in Patients With Secondary Peritonitis: A Propensity Score-matched Case-control Analysis

OBJECTIVE

To evaluate the influence of a visceral protective layer (VPL) on the formation of enteroatmospheric fistulae (EAF) in open abdomen treatment (OAT) for peritonitis.

BACKGROUND

EAF formation is a severe complication of OAT. Despite the widespread use of OAT, there are no robust evidence-based recommendations for preventing EAF.

METHODS

A total of 120 peritonitis patients with secondary peritonitis as a result of a perforation of a hollow viscus or anastomotic insufficiency who had undergone OAT were included, and 14 clinical parameters were recorded in prospective OAT databases at 2 tertiary referral centers. For this analysis, patients with a VPL were assigned to the treatment group and those without a VPL to the control group. Propensity Score (PS) matching was performed. Known risk factors in OAT such as malignant disease, mortality, emergency operation, OAT duration, and fascial closure were matching variables. The influence of VPL on EAF formation was statistically evaluated using logistic regression analysis.

RESULTS

With 34 patients in each group, no notable differences were identified with regard to age, sex, underlying disease, mortality, emergency operation, fascial closure, and OAT duration. Overall, a mortality rate of 22.1% for OAT due to peritonitis was observed. Mean OAT duration was approximately 9 days, and secondary fascial closure was achieved in more than two-thirds of all patients. Fascial traction was used in more than 75% of cases. EAF formation was significantly more frequent in the control group (EAF formation: VPL group 2.9% vs control 26.5%; P = 0.00). In the final regression analysis, the use of VPL resulted in a significant reduction in the risk of EAF formation (odds ratio 0.08; 95% confidence interval 0.01-0.71, P = 0.02), which translates to a relative risk reduction of 89.1%.

CONCLUSION

VPL effectively prevents EAF formation during OAT in patients with peritonitis. We recommend the consistent use of VPL as part of a standardized OAT treatment algorithm.

Successful improved peripheral tissue perfusion was seen in patients with atherosclerosis after 12 months of treatment with aged garlic extract

Patients with arteriolosclerosis have impaired microvascular perfusion leading to impaired wound healing. Aged garlic extract has shown to have a positive impact on vascular elasticity. The present study aimed to assess the effect of long‐term treatment with AGE on peripheral tissue perfusion in patients with confirmed atherosclerosis. Ninety three patients with a CT‐scan confirmed coronary artery arteriolosclerosis were randomised in a double‐blind manner to placebo or 2400 mg AGE daily for 1 year. Peripheral tissue perfusion was evaluated at 0‐ and 12‐months using Laser Speckle Contrast Imaging. Measurement of post occlusive reactive hyperemia (PORH) and cutaneous vascular conductance (CVC) using acetylcholine iontophoresis (Ach) was conducted. After 12 months a significant increase of 21.6% (95% CI 3.2%‐40.0%, P < .05) was seen in the relative change of PORH in the AGE compared with the placebo group. The same response was seen for CVC and Ach with an increase of 21.4% (95% CI 3.4%‐39.4%, P < .05) in the AGE group compared with the placebo group. Aged garlic extract regenerated peripheral tissue perfusion and increase microcirculation in patients with arteriolosclerosis. Adequate peripheral tissue perfusion and tissue oxygen tension are important prerequisites for successful tissue repair. Restored microcirculation in patients could hypothetically facilitate wound healing.

Successful treatment of enterocutaneous fistula after esophagectomy with scopolamine ointment and negative pressure wound therapy: a case report

Background

Despite improved surgical techniques and perioperative management, anastomotic leakage (AL) after esophageal cancer surgery remains a potential complication. In most cases, spontaneous healing upon proper drainage is observed, but sometimes, AL results in intractable enterocutaneous fistulas. We here report a case of intractable enterocutaneous fistula caused by post-esophagectomy AL and successfully treated by scopolamine ointment and negative pressure wound therapy (NPWT).

Case presentation

A 77-year-old man underwent thoracoscopic subtotal esophagectomy with 3-field lymph node dissection, followed by gastric tube reconstruction through the posterior mediastinal route. On the 6th postoperative day, AL was identified, forming an enterocutaneous fistula. Initially, conservative treatment was performed, but the fistula failed to close. We hypothesized that the substantial amount of exudate might be hampering fistula closure. Scopolamine ointment was used to reduce the amount of fluid. NPWT was also initiated to promote wound healing. Approximately 3 weeks after the beginning of the treatment, the fistula closed; oral intake became possible, and the patient was discharged from the hospital without any symptoms.

Conclusions

The combination of scopolamine ointment and NPWT may be regarded as one effective treatment option for intractable enterocutaneous fistula due to AL after esophagectomy.

Aged garlic extract preserves cutaneous microcirculation in patients with increased risk for cardiovascular diseases: A double-blinded placebo-controlled study

Laser Doppler velocimetry estimates tissue perfusion providing a record of microvascular blood flow. Patients with heart disease or diabetes mellitus have impaired microvascular perfusion leading to impaired wound healing. Aged garlic extract (AGE) has a positive effect on vascular elasticity. This study aimed to assess the effect of long-term treatment with AGE on cutaneous tissue perfusion. A total of 122 patients with Framingham Risk Score ≥ 10 were randomised in a double-blinded manner to placebo or 2400 mg AGE daily for 1 year and monitored. Cutaneous microcirculation was measured at 0 and 12 months using laser Doppler velocimetry. A repeated measures analysis of variance (ANOVA) with a Greenhouse-Geisser correction determined that mean post-occlusive reactive hyperaemia differed significantly between time points. The mean percent change between the two time points 0 and 12 months was 102, 64 (174, 15)% change for AGE and 78, 62 (107, 92)% change for the placebo group (F[1, 120] = 5. 95, P < 0.016), 12 months of AGE increases the microcirculation in patients with an increased risk for cardiovascular events estimated using the Framingham risk score. Increased microcirculation could hypothetically facilitate wound healing.

Prognostic Factors for Enteroatmospheric Fistula in Open Abdomen Treated with Negative Pressure Wound Therapy: a Multicentre Experience

BACKGROUND

Reductions in mortality were reported with negative pressure wound therapy for laparostomy. However, some authors have voiced concern over an increased risk of enteroatmospheric fistulae. In this retrospective study, we hypothesized that surgical and metabolic derangements could increase the incidence of enteroatmospheric fistulae. We aimed to assess our experience and report long-term outcomes.

METHODS

A multicentre review of all patients with a laparostomy managed with negative pressure wound therapy between 2005 and 2015 was undertaken. Features associated with enteroatmospheric fistulae were included in multivariate logistic regression.

RESULTS

Fifty-seven patients were treated according to uniform protocol. Fourteen per cent (8/57) presented enteroatmospheric fistulae. Mesenteric ischaemia and preoperative arterial serum lactate >3.5 mmol/L were associated with a significantly increased risk of enteroatmospheric fistulae. Preoperative arterial serum lactate >3.5 mmol/L was an independent predictor of enteroatmospheric fistulae with an odds ratio of 12.41 (95% CI 1.54-99.99). All mesenteric ischaemia patients with anastomosis (5/15) presented enteroatmospheric fistulae. In-hospital mortality was 26.3% (15/57). One-year mortality was 33.3% (19/57). Incisional hernia rate was 5.2% (2/38) after 14.2 (2.4-56.3) months of follow-up.

DISCUSSION

Mesenteric ischaemia increases the risk of enteroatmospheric fistulae. Anastomosis should only be created in revascularized patients. When mesenteric vascularization is not restored, diversion is advised.

Prophylactic vacuum sealing drainage (VSD) in the prevention of postoperative surgical site infections in pediatric patients with contaminated laparotomy incisions

Surgical site infection (SSI) continues to be an issue in abdominal surgery, especially for contaminated (class III) and dirty-infected (class IV) wounds. Vacuum sealing drainage (VSD) was reported effective in the management of various types of wounds or skin grafts. Our goal was to investigate the efficacy of prophylactic VSD to better orient their medicosurgical care of high-risk incisions following laparotomy in a pediatric population.A total of 331 pediatric patients with contaminated (class III) and dirty-infected (class IV) wounds following emergency laparotomy were retrospectively reviewed between January 2005 and January 2013. Among them, 111 cases were placed with prophylactic VSD when incisions were closed. Clinical outcomes, including, overall surgical site complication, device effectiveness, and mean postoperative LOS were evaluated based on VSD usage or not.VSD was applied for an average of 5.8 days (range, 5-7 days), with 3 to 15 mL sucked fluid. The overall SSIs rate was 3% for patients with prophylactic VSD and 17% for patients with convention dressing (OR, 0.27; 95% CI, 0.10-0.71, P = 0.004). In patients with prophylactic VSD, only 1 of 96 wound developed postoperative incision dehiscence, which is significant reduced compared with patients for conventional dressings (OR, 0.12; 95% CI, 0.01-0.95; P = 0.017) (Table 2). It also exhibited a decreased mean postoperative LOS (P < 0.001) for prophylactic VSD over conventional dressings.Our study demonstrated beneficial postoperative clinical effects of prophylactic VSD for high-risk laparotomy incisions following emergency laparotomy, such as shorter length of hospitalization, which may be attributed to the reduced overall SSIs rate.

Prophylactic negative pressure wound therapy in colorectal surgery. Effects on surgical site events: current status and call to action

Surgical site events, including surgical site infections (SSI), represent a major problem in general surgery. SSI are responsible of nuisance for patients, and can lead to important complications and disability, often needing prolonged postoperative stay with specific treatment and recovery in Intensive Care Units. These justify the higher costs due to SSI. Despite the growing body of evidence concerning SSI in general surgery, literature dealing with SSI after colorectal surgery is scarce, reflecting in suboptimal perception of such a relevant issue by colorectal surgeons and health authorities in Italy, though colorectal surgery is associated with higher rates of SSI. The best strategy for reducing the impact of SSI on costs of care and patients quality of life would be the development of a preventive bundle, similar to that adopted in the US through the colorectal section of the National Surgery Quality Improvement Project of the American College of Surgeons (ACS-NSQIP). This policy has been showed to significantly reduce the rates of SSI. In this scenario, incisional negative pressure wound therapy (NPWT) is likely to play a pivotal role. We herein reviewed the literature to report on the current status of preventive NPWT on surgical wounds of patients undergoing colorectal procedures with primary wound closure, suggesting evidence-based measures to reduce the impact of SSI, and to contain the costs associated with conventional NPWT devices by means of newer available technologies. Some explicative real life cases are presented.

Comparative study of the microvascular blood flow in the intestinal wall, wound contraction and fluid evacuation during negative pressure wound therapy in laparostomy using the V.A.C. abdominal dressing and the ABThera open abdomen negative pressure therapy system

This study aimed to compare the changes in microvascular blood flow in the small intestinal wall, wound contraction and fluid evacuation, using the established V.A.C. abdominal dressing (VAC dressing) and a new abdominal dressing, the ABThera open abdomen negative pressure therapy system (ABThera dressing), in negative pressure wound therapy (NPWT). Midline incisions were made in 12 pigs that were subjected to treatment with NPWT using the VAC or ABThera dressing. The microvascular blood flow in the intestinal wall was measured before and after the application of topical negative pressures of −50, −75 and −125mmHg using laser Doppler velocimetry. Wound contraction and fluid evacuation were also measured. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced to 64·6±6·7% (P <0·05) after the application of −50mmHg using the VAC dressing, and to 65·3±9·6% (P <0·05) after the application of −50mmHg using the ABThera dressing. The blood flow was significantly reduced to 39·6±6·7% (P <0·05) after the application of −125mmHg using VAC and to 40·5±6·2% (P <0·05) after the application of −125mmHg using ABThera. No significant difference in reduction in blood flow could be observed between the two groups. The ABThera system afforded significantly better fluid evacuation from the wound, better drainage of the abdomen and better wound contraction than the VAC dressing.

Blood flow response in small intestinal loops at different depths during negative pressure wound therapy of the open abdomen

High closure rates of the open abdomen have been reported following negative pressure wound therapy (NPWT). However, the method has occasionally been associated with increased development of intestinal fistulae. We have previously shown that the application of NPWT to the open abdomen causes a decrease in microvascular blood flow in the small intestinal loop and the omentum adjacent to the visceral protective layer of the dressing. In this study we investigate whether the negative pressure affects only small intestinal loops lying directly below the dressing or if it also affects small intestinal loops that are not in direct contact with the dressing. Six pigs underwent midline incision and application of NPWT to the open abdomen. The microvascular blood flow was measured in four intestinal loops at different depths from the visceral protective layer, at two different locations: beneath the dressing and at the anterior abdominal wall, before and after the application of NPWT of -50, -70, -100, -120, -150 and -170 mmHg, using laser Doppler velocimetry. Negative pressures between -50 and -170 mmHg caused a significant decrease in the microvascular blood flow in the intestinal loops in direct contact with the visceral protective layer. A slight, but significant, decrease in blood flow was also seen in the intestinal loops lying beneath these loops. The decrease in microvascular blood flow increased with the amount of negative pressure applied. No difference in blood flow was seen in the intestinal loops lying deeper in the abdominal cavity. A decrease in blood flow was seen in the upper two intestinal loops located apically and anteriorly, but not in the lower two, indicating that this is a local effect and that pressure decreases with distance from the source. A long-term decrease in blood flow in the intestinal wall may induce ischaemia and secondary necrosis in the intestinal wall, which could promote the development of intestinal fistulae. We believe that NPWT of the open abdomen is a very effective treatment, but that it could be improved by gaining more knowledge on the mechanisms involved.

Effects of a new pocket device for negative pressure wound therapy on surgical wounds of patients affected with Crohn's disease: a pilot trial

INTRODUCTION

Surgical site infections (SSIs) affect costs of care and prolong length of stay. Crohn's disease (CD) represents an independent risk factor for SSI. The risk can be further increased by concomitant administration of immunosuppressive drugs and poor performance status at the time of surgery. Patients suffering from CD often need more than one surgical intervention during life, sometimes requiring fashioning of a stoma. The aim of this pilot study was to compare a portable device for negative pressure wound therapy (PICO, Smith & Nephew, London, UK) to conventional gauze dressings in patients undergoing surgery for stricturing CD.

METHODS

Between January 2010 and November 2011, this controlled trial enrolled 30 patients, who were assigned to treatment with either PICO (n = 13) or conventional dressings (n = 17). Each patient completed a 3-month follow-up.

RESULTS

Patients receiving PICO experienced significantly less postoperative wound complications (P = .001) and SSI (P = .017) compared with those who received conventional dressings. This resulted in shorter hospital stay (P = .0007). No significant differences in cosmetic results were found.

CONCLUSION

These data suggest that PICO allows faster and safe discharge by reducing the incidence of SSI and wound-related complications in selected patients undergoing surgical intervention for stricturing CD. This could be particularly useful in patients receiving steroids.

Comparative study of the microvascular blood flow in the intestinal wall during conventional negative pressure wound therapy and negative pressure wound therapy using paraffin gauze over the intestines in laparostomy

Higher closure rates of the open abdomen have been reported with negative pressure wound therapy (NPWT) than with other kinds of wound management. We have recently shown that NPWT decreases the blood flow in the intestinal wall, and that the blood flow could be restored by inserting a protective disc over the intestines. The aim of the present study was to investigate whether layers of Jelonet™ (Smith & Nephew) dressing (paraffin tulle gras dressing made from open weave gauze) over the intestines could protect the intestines from hypoperfusion. Midline incisions were made in ten pigs and were subjected to treatment with NPWT with and without four layers of Jelonet over the intestines. The microvascular blood flow was measured in the intestinal wall before and after the application of topical negative pressures of -50, -70 and -120 mmHg, using laser Doppler velocimetry. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced, to 61 ± 7% (P < 0·001), after the application of -50 mmHg using conventional NPWT, and to 62 ± 7% (P < 0·001) after the application of -50 mmHg with Jelonet dressings between the dressing and the intestines. The blood flow was significantly reduced, to 38 ± 5% (P < 0·001), after the application of -70 mmHg, and to 42 ± 6% (P < 0·001) after the application of -70 mmHg with Jelonet dressings. The blood flow was significantly reduced, to 34 ± 9% (P < 0·001), after the application of -120 mmHg, and to 38 ± 6% (P < 0·001) after the application of -120 mmHg with Jelonet dressings. The use of four layers of Jelonet over the intestines during NPWT did not prevent a decrease in microvascular blood flow in the intestinal wall.

Pressure transduction and fluid evacuation during conventional negative pressure wound therapy of the open abdomen and NPWT using a protective disc over the intestines

BACKGROUND

Negative pressure wound therapy (NPWT) has gained acceptance among surgeons, for the treatment of open abdomen, since very high closure rates have been reported with this method, compared to other kinds of wound management for the open abdomen. However, the method has occasionally been associated with increased development of fistulae. We have previously shown that NPWT induces ischemia in the underlying small intestines close to the vacuum source, and that a protective disc placed between the intestines and the vacuum source prevents the induction of ischemia. In this study we compare pressure transduction and fluid evacuation of the open abdomen with conventional NPWT and NPWT with a protective disc.

METHODS

Six pigs underwent midline incision and the application of conventional NPWT and NPWT with a protective disc between the intestines and the vacuum source. The pressure transduction was measured centrally beneath the dressing, and at the anterior abdominal wall, before and after the application of topical negative pressures of -50, -70 and -120 mmHg. The drainage of fluid from the abdomen was measured, with and without the protective disc.

RESULTS

Abdominal drainage was significantly better (p < 0. 001) using NPWT with the protective disc at -120 mmHg (439 ± 25 ml vs. 239 ± 31 ml), at -70 mmHg (341 ± 27 ml vs. 166 ± 9 ml) and at -50 mmHg (350 ± 50 ml vs. 151 ± 21 ml) than with conventional NPWT. The pressure transduction was more even at all pressure levels using NPWT with the protective disc than with conventional NPWT.

CONCLUSIONS

The drainage of the open abdomen was significantly more effective when using NWPT with the protective disc than with conventional NWPT. This is believed to be due to the more even and effective pressure transduction in the open abdomen using a protective disc in combination with NPWT.

Macroscopic changes during negative pressure wound therapy of the open abdomen using conventional negative pressure wound therapy and NPWT with a protective disc over the intestines

BACKGROUND

Higher closure rates of the open abdomen have been reported with negative pressure wound therapy (NPWT) than with other wound management techniques. However, the method has occasionally been associated with increased development of fistulae. We have previously shown that NPWT induces ischemia in the underlying small intestines close to the vacuum source, and that a protective disc placed between the intestines and the vacuum source prevents the induction of ischemia. In the present study we compare macroscopic changes after 12, 24, and 48 hours, using conventional NPWT and NPWT with a protective disc between the intestines and the vacuum source.

METHODS

Twelve pigs underwent midline incision. Six animals underwent conventional NPWT, while the other six pigs underwent NPWT with a protective disc inserted between the intestines and the vacuum source. Macroscopic changes were photographed and quantified after 12, 24, and 48 hours of NPWT.

RESULTS

The surface of the small intestines was red and mottled as a result of petechial bleeding in the intestinal wall in all cases. After 12, 24 and 48 hours of NPWT, the area of petechial bleeding was significantly larger when using conventional NPWT than when using NPWT with the protective disc (9.7 ± 1.0 cm(2) vs. 1.8 ± 0.2 cm(2), p < 0.001, 12 hours), (14.5 ± 0.9 cm(2) vs. 2.0 ± 0.2 cm(2), 24 hours) (17.0 ± 0.7 cm(2) vs. 2.5 ± 0.2 cm(2) with the disc, p < 0.001, 48 hours)

CONCLUSIONS

The areas of petechial bleeding in the small intestinal wall were significantly larger following conventional NPWT after 12, 24 and 48 hours, than using NPWT with a protective disc between the intestines and the vacuum source. The protective disc protects the intestines, reducing the amount of petechial bleeding.