Key messages
- We do not know if negative pressure wound therapy (NPWT, defined as pressure lower than a given reference pressure, generally causing suction) helps abdominal wounds to heal quicker or reduces potential harmful effects compared with using a Bogota bag (a sterilised fluid bag used for closing abdominal wounds).
- We do not know if a Suprasorb CNP system (a type of NPWT) helps abdominal wounds to heal quicker or reduces potential harmful effects compared with using an ABThera system (another type of NPWT).
- We do not know if NPWT increases the risk of bowel perforation. Future research should explore healing time, potential unwanted or harmful effects, all-cause mortality, length of hospital stay, health-related quality of life, reoperation rate, wound infection, and pain outcomes.
What is an open abdomen?
Sometimes a person's abdomen needs to be left open while it heals after surgery. However, high death rates are associated with leaving the abdomen open after surgery. Managing the open abdomen is a considerable burden for patients and doctors.
How is this managed?
NPWT uses a sealed dressing connected to a vacuum pump to drain fluid from a wound. However, the safety and effectiveness of NPWT as a treatment for open abdomen is still uncertain.
NPWT has been used in recent years to treat non-trauma patients after abdominal surgery. Non-trauma patients are people who need surgery for conditions that are not caused by trauma (e.g. abdominal infection, cancer, ischaemia).
What did we want to find out?
We wanted to find out whether NPWT is effective in treating the open abdomen after surgery in non-trauma patients in any care setting. We wanted to compare NPWT with other treatment methods or other types of NPWT, and we were particularly interested in their effects on the following:
- wound closure (how long it took for wounds to close and how many people had wounds that fully closed);
- if there were any harmful or unwanted effects (e.g. bowel perforation);
- death rate;
- participant health-related quality of life or health status;
- length of hospital stay;
- reoperation rate;
- wound infection; and
- pain.
What did we do?
We searched for studies that compared NPWT with any other type of temporary abdominal closure in non-trauma patients with open abdomen. We also included studies that compared different types of NPWT systems for managing the open abdomen in non-trauma patients. We had no restrictions with respect to language, date of publication, or where the study was conducted. We rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found one single-centre study conducted in Turkey, which included 40 adults with open abdomen. Participants were randomly allocated to treatment with either NPWT or a Bogota bag. We cannot tell from the results whether when compared to Bogota bag, NPWT reduces:
- the time needed for wounds to completely close;
- harmful or unwanted effects (bowel perforation);
- death rate; or
- length of hospital stay between the groups.
The study did not report the proportion of people with wounds that were successfully closed, participant health-related quality of life, reoperation rate, wound infection, or pain.
We found another single-centre study, which was conducted in Austria and included 34 adults with open abdomen. Participants were randomly allocated to treatment with either a Suprasorb CNP system or an ABThera system. We cannot tell from the results whether when compared to an ABThera system, a Suprasorb CNP system reduces:
- the proportion of people with wounds that were successfully closed;
- harmful or unwanted effects (bowel perforation);
- death rate; or
- reoperation rate between the groups.
The study did not report the time needed for wounds to completely close, participant health-related quality of life, length of hospital stay, wound infection, or pain.
What are the limitations of the evidence?
We only found two relevant studies, so we are uncertain about the benefits or harms of using NPWT compared with using a Bogota bag or different types of NPWT systems. We did not find any studies that compared NPWT with other types of temporary abdominal closure.
How up to date is this evidence?
The evidence is up to date to October 2021.
Based on the available trial data, we are uncertain whether NPWT has any benefit in primary fascial closure of the abdomen, adverse events (fistulae formation), all-cause mortality, or length of hospital stay compared with the Bogota bag. We are also uncertain whether the Suprasorb CNP system has any benefit in primary fascial closure of the abdomen, adverse events, all-cause mortality, or reoperation rate compared with the ABThera system. Further research evaluating these outcomes as well as participant health-related quality of life, wound infection, and pain outcomes is required. We will update this review when data from the large studies that are currently ongoing are available.
Management of the open abdomen is a considerable burden for patients and healthcare professionals. Various temporary abdominal closure techniques have been suggested for managing the open abdomen. In recent years, negative pressure wound therapy (NPWT) has been used in some centres for the treatment of non-trauma patients with an open abdomen; however, its effectiveness is uncertain.
To assess the effects of negative pressure wound therapy (NPWT) on primary fascial closure for managing the open abdomen in non-trauma patients in any care setting.
In October 2021 we searched the Cochrane Wounds Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL EBSCO Plus. To identify additional studies, we also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses, and health technology reports. There were no restrictions with respect to language, date of publication, or study setting.
We included all randomised controlled trials (RCTs) that compared NPWT with any other type of temporary abdominal closure (e.g. Bogota bag, Wittmann patch) in non-trauma patients with open abdomen in any care setting. We also included RCTs that compared different types of NPWT systems for managing the open abdomen in non-trauma patients.
Two review authors independently performed the study selection process, risk of bias assessment, data extraction, and GRADE assessment of the certainty of evidence.
We included two studies, involving 74 adults with open abdomen associated with various conditions, predominantly severe peritonitis (N = 55). The mean age of the participants was 52.8 years; the mean proportion of women was 39.2%. Both RCTs were carried out in single centres and were at high risk of bias.
Negative pressure wound therapy versus Bogota bag
We included one study (40 participants) comparing NPWT with Bogota bag. We are uncertain whether NPWT reduces time to primary fascial closure of the abdomen (NPWT: 16.9 days versus Bogota bag: 20.5 days (mean difference (MD) -3.60 days, 95% confidence interval (CI) -8.16 to 0.96); very low-certainty evidence) or adverse events (fistulae formation, NPWT: 10% versus Bogota: 5% (risk ratio (RR) 2.00, 95% CI 0.20 to 20.33); very low-certainty evidence) compared with the Bogota bag. We are also uncertain whether NPWT reduces all-cause mortality (NPWT: 25% versus Bogota bag: 35% (RR 0.71, 95% CI 0.27 to 1.88); very low-certainty evidence) or length of hospital stay compared with the Bogota bag (NPWT mean: 28.5 days versus Bogota bag mean: 27.4 days (MD 1.10 days, 95% CI -13.39 to 15.59); very low-certainty evidence). The study did not report the proportion of participants with successful primary fascial closure of the abdomen, participant health-related quality of life, reoperation rate, wound infection, or pain.
Negative pressure wound therapy versus any other type of temporary abdominal closure
There were no randomised controlled trials comparing NPWT with any other type of temporary abdominal closure.
Comparison of different negative pressure wound therapy devices
We included one study (34 participants) comparing different types of NPWT systems (Suprasorb CNP system versus ABThera system). We are uncertain whether the Suprasorb CNP system increases the proportion of participants with successful primary fascial closure of the abdomen compared with the ABThera system (Suprasorb CNP system: 88.2% versus ABThera system: 70.6% (RR 0.80, 95% CI 0.56 to 1.14); very low-certainty evidence). We are also uncertain whether the Suprasorb CNP system reduces adverse events (fistulae formation, Suprasorb CNP system: 0% versus ABThera system: 23.5% (RR 0.11, 95% CI 0.01 to 1.92); very low-certainty evidence), all-cause mortality (Suprasorb CNP system: 5.9% versus ABThera system: 17.6% (RR 0.33, 95% CI 0.04 to 2.89); very low-certainty evidence), or reoperation rate compared with the ABThera system (Suprasorb CNP system: 100% versus ABThera system: 100% (RR 1.00, 95% CI 0.90 to 1.12); very low-certainty evidence). The study did not report the time to primary fascial closure of the abdomen, participant health-related quality of life, length of hospital stay, wound infection, or pain.