Peritoneal Vacuum Therapy to Reduce Inflammatory Response From Abdominal Sepsis/Injury

Overview

This pilot study will evaluate the effectiveness in actively removing the peritoneal fluid through the use of a commercial suction device compared to passive drainage of the same peritoneal fluid drained through standard surgical drains under bulb suction only, in critically ill patients who require an "open abdomen". Both techniques being used, the commercial KCI AbThera™ device and home made "Stampede" VAC system, are currently approved for use in Canada and used in our facility. The use or non-use of the open abdomen and its relationship to intra-abdominal hypertension (IAH) and the abdominal compartment syndrome (ACS), the level of IAH must be treated and if so how should be treated - remain controversial. The ultimate treatment for IAH/ACS is to leave the abdominal fascia open after laparotomy, utilizing some form of temporary abdominal closure (TAC) techniques, resulting in an "open abdomen"(OA). The decision to accept an OA can only be made in the operating room and is typically made quite arbitrarily (there is no current standard or protocol),and the TAC used is based on the surgeon's best judgment. The study intends to randomize patients after it has been decided that a TAC is required, which will be applied in the operating room while the patient is fully anesthetized. The only intervention required is to obtain small aliquots (a teaspoonful-15ml) of blood for the evaluation of inflammatory mediators levels, as well as the same volume of intra-peritoneal fluid-that is typically discarded in patients with OA.

Excessive pressure within the peritoneal cavity, known as intra-abdominal hypertension (IAH), can adversely affect not only intra-peritoneal organ function, but also other organ systems throughout the body. When IAH \> 20 mmHg induces new organ dysfunction, a potentially lethal condition known as the abdominal compartment syndrome (ACS) is defined. Practically, this syndrome can be considered multi-system organ failure occurring from severe IAH. While the physical effects of IAH/ACS are increasingly being described, the humoral ones, related to IAH-induced ischemia are poorly understood. Recent animal work suggests that aggressively removing intra-peritoneal fluids, assumed to be vasoactive mediator-rich, leads to better systemic outcomes. There is no human data to support this however. Previous attempts at peritoneal drainage in inflammatory conditions such as sepsis and pancreatitis where not conclusive, but this may have been due to the inefficiency of the systems used and the lack of attention to IAH. Recently, efficient systems providing a temporary abdominal closure (TAC) to both drain intra-peritoneal fluids and to control IAH have been introduced. One of these dressing systems, known as the KCI AbThera™ Abdominal Dressing is currently approved for use in Canada as a temporary abdominal closure (TAC) device but its role in ameliorating systemic sepsis/SIRS has not been evaluated. We propose a randomized trial of using either the "home Calgary Stampede Vac" involving wall suction or the KCI AbThera™ Abdominal Dressing, to dress the abdomen whenever the operative surgeon determines that an open abdomen is warranted to treat the patient. In general, others have hypothesized that cytokines, especially peritoneal levels, are sensitive indicators of the post-operative inflammatory reaction and may predict complications. In experimental models IL-6 levels are higher in non-survivors. Further, previous work has noted that the blood level of IL-6, which has a longer half life than TNF-α or IL-1β, is a good index of the overall cytokine cascade activation. Thus the main outcomes to be compared will be between mean cytokine levels measured in each of the two treatment groups - to determine if the KCI AbThera™ Abdominal Dressing can significantly reduce the blood concentration of IL-6 when compared with the "Stampede VAC" system. We are hoping to better understand how the body responds to the inflammatory process that naturally occurs during and after an episode of intra-abdominal hypertension, to identify signals or markers of inflammation and infection as well as its progression and outcome.