Review question
A surgical drain is a tube used to remove blood, pus or other fluid from a wound. We reviewed the evidence about whether inserting wound drains following leg artery surgery resulted in fewer complications compared with no drains.
Background
Patients who have severe blockages in the arteries of their legs often need to have the blockages treated. These blockages can be treated with surgery, and there are several different types of operation that can be used. Arterial bypass is an operation in which the blockage is bypassed by using a piece of vein or a synthetic tube so that the blood can go around the obstruction. An endarterectomy is an operation where the surgeon removes the fatty material that is causing the blockage, thereby improving the flow of blood. Sometimes after surgery on leg arteries, surgeons place drainage tubes in the wounds. It is thought that these drains may help to reduce infection, prevent the build-up of blood or other fluids in the wound, and avoid some other complications after operations. These benefits are not proven and nobody knows if drains are truly helpful. It is possible that drains could cause harm by allowing infection into a wound, by causing bleeding and by prolonging the time a patient spends in hospital. Nobody knows if surgeons should use drains in every wound all of the time, or only in cases where they think a drain is needed.
Study characteristics
In June 2016 we searched for randomised controlled trials (RCTs) involving the use of drains after leg artery surgery. We identified three eligible trials involving 333 wounds in 222 patients, mainly aged over 65, who had leg artery surgery. Both men and women were included and all of the wounds were in the groin area as part of bypass and endarterectomy operations to improve blood flow.
Key results
The studies involved small numbers of patients and were not clearly described. All three studies had serious weaknesses in the way they were designed and performed. The results of the individual studies do not provide reliable information because of weaknesses in study design. It is unclear whether wound drains are beneficial or harmful because we did not find any useful information. None of the studies gave information on whether drains shortened or lengthened the number of days that patients had to spend in hospital. None of the studies gave information about how drains affect patients' quality of life.
Quality of the evidence
Overall, we found that the quality of the evidence about the effects of drains after leg artery surgery was very low and we were not able to tell whether drains lead to benefits or harms for patients. Better quality research is needed if patients and healthcare providers think that this is an important topic.
This plain language summary is up to date as of 8 June 2016.
The data upon which to base practice in this area are limited and prone to biases. Complete uncertainty remains regarding the potential benefits and harms associated with the use of wound drains in lower limb arterial surgery due to the small number of completed studies and weaknesses in their design and conduct. Higher quality evidence is needed to inform clinical decision making. To our knowledge, no trials on this topic are currently active.
Drains are often used in leg wounds after vascular surgery procedures despite uncertainty regarding their benefits. Drains are placed with the aim of reducing the incidence and size of blood or fluid collections. Conversely, drains may predispose patients to infection and may prolong hospitalisation. Surgeons need robust data regarding the effects of drains on complications following lower limb arterial surgery.
To determine whether routine placement of wound drains results in fewer complications following lower limb arterial surgery than no drains.
In June 2016 we searched: the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE and EBSCO CINAHL. We also searched clinical trial registries for ongoing studies.There were no restrictions with respect to language, date of publication or study setting.
We considered randomized controlled trials (RCTs) that evaluated the use of any type of drain in lower limb arterial surgery.
Two authors independently determined study eligibility, extracted data and performed an assessment of bias. An effort was made to contact authors for missing data. The methods and results of each eligible study were summarised and we planned to pool data in meta-analyses when it was considered appropriate, based upon clinical and statistical homogeneity.
We identified three eligible trials involving a total of 222 participants with 333 groin wounds. Suction drainage was compared with no drainage in all studies. Two studies were parallel-group, randomized controlled trials, and one was a split-body, randomized controlled trial. Trial settings were not clearly described. Patients undergoing bypass and endarterectomy procedures were included, but none of the studies provided details on the severity of the underlying arterial disease.
We deemed all of the studies to be at a high risk of bias in three or more domains of the 'Risk of bias' assessment and overall the evidence was of very low quality. Two out of three studies had unit of analysis errors (with multiple wounds within patients analysed as independent) and it was not possible to judge the appropriateness of the analysis of the third. Meta-analysis was not appropriate, firstly because of clinical heterogeneity, and secondly because we were not able to adjust for the analysis errors in the individual trials. One trial yielded data on surgical site infections (SSI; the primary outcome of the review): there was no clear difference between drained and non-drained wounds for SSI (risk ratio 1.33; 95% confidence interval 0.30 to 5.94; 50 participants with bilateral groin wounds; very low quality evidence). It was not possible to evaluate any other outcomes from this trial. The results from the other two studies are unreliable because of analysis errors and reporting omissions.