Resumen de Evaluation of fluid production and seroma formation after placement of closed suction drains in clean subcutaneous surgical wounds of dogs: 77 cases (2005–2012)
Objective—To evaluate fluid production and factors associated with seroma formation after placement of closed suction drains in clean surgical wounds in dogs.
Design—Retrospective case series.
Animals—77 client-owned dogs with a subcutaneous closed suction drain placed following a clean surgical procedure.
Procedures—Medical records (January 2005 to June 2012) were reviewed, and signalment, site of surgery and underlying disease process, histologic evaluation results, total drain fluid production, fluid production rate (mL/kg/h) at 12-hour intervals, cytologic evaluation of drain fluid, and development of dehiscence, infection, or seroma were recorded. Associations among variables were evaluated.
Results—The most common complication was dehiscence (n = 18), followed by seroma (14) and infection (4). Dogs that developed a seroma had significantly greater total drain fluid volume relative to body weight and greater fluid production rate at 24 and 72 hours as well as the last time point measured before drain removal. Dogs in which drains were removed when fluid production rate was > 0.2 mL/kg/h (0.09 mL/lb/h) were significantly more likely to develop a seroma.
Conclusions and Clinical Relevance—Seroma formation was more common in dogs with a higher rate of fluid production relative to body weight, but was not associated with the number of days that a closed suction drain remained in situ. Dogs may be at greater risk of seroma formation if their drains are removed while drainage is still occurring at a rate > 0.2 mL/kg/h.
Surgical drains are commonly used following soft tissue surgical procedures. By removing serum and blood from the wound, drains reduce fluid pockets that can cause discomfort to the patient, delay healing, exacerbate inflammation, or facilitate infection.1,2 Drains evacuate inflammatory mediators, foreign material, necrotic debris, and bacteria. Closed suction (active) drains are postulated to have a lower risk for nosocomial infection, compared with open (passive) drains; prevent skin irritation secondary to maceration by draining fluid; allow for quantification of fluid production; and improve apposition of tissue flaps and skin grafts because of the suction effect on the surgical bed.2 Despite their many benefits, using drains is not without risk. Perhaps the most concerning adverse effect of prophylactic drain placement in a noncontaminated surgical site is the risk of infection. Drain placement automatically converts a clean procedure into a clean-contaminated one.1,2 A drain creates a conduit between the sterile surgical site and the environment and may allow retrograde bacterial migration. Drains cause an inflammatory (foreign body) response, even when constructed of relatively inert materials such as polyethylene, polyvinyl chloride, or silicone rubber. This response decreases resistance to bacterial colonization of the wound.3 Infection risk may be minimized by managing factors such as drain type, size, and duration of placement4; however, these factors must be balanced with drain efficacy and the risks of occlusion and premature removal.
Placement and management of drains have not been well evaluated in veterinary medicine. Anecdotally, clinicians typically make subjective determinations about drainage, type of drain, and duration of drain placement on the basis of personal experience. It has been recommended to remove thoracostomy tubes when fluid production rate is < 2.0 mL/kg/d (0.9 mL/lb/d); however, a retrospective analysis of outcomes found that there was no difference in hospital stay on the basis of rate of fluid production at the time of thoracostomy tube removal.5 The current recommendation for closed suction drains is to remove them as early as possible, on the basis of evidence of decreasing fluid production and a plateau in fluid volume.1 However, no clear standards for rate of fluid production, timing of drain removal, or how to weigh the importance of these variables have been published. There has been no study in the mainstream veterinary literature examining the outcomes following closed suction drainage of subcutaneous surgical wounds in dogs.
The purpose of the study reported here was to evaluate fluid production and factors associated with seroma formation after placement of closed suction drains in clean surgical wounds in dogs. We hypothesized that the use of these drains in clean surgical fields for skin and reconstructive surgery would be associated with a low rate of complications such as subsequent infection or seroma development. Our major goal was to document the rates of fluid production that might be expected following placement of closed suction drains in noninfected sites and identify useful clinical guidelines for drain removal.
