No benefit from post-caesarean wound drainage A prospective randomised controlled trial

Drainage systems have been routinely used since the early modern surgical era [1], on the grounds that body fluids and necrotic material offer an optimal growth medium for microorganisms [2]. They are also thought to decrease postoperative pain and wound infection. Suction is the preferred modality: a 1988 study showed that a suction tube placed beneath the rectos sheath was significantly superior to subcutaneous corrugated drainage in preventing post-caesarean wound infection [3]. Thus, in the Department of Obstetrics, Zurich University Hospital and in other European centres, twin subfascial and subcutaneous suction tube insertion has until recently been systematic after caesarean section. In contrast, in other obstetric centres, especially in the UK, in Australia and in the USA, suction tubes are not in routine use. The weight of experimental evidence in favour of the practice is less impressive than that of tradition. Suction drains the wound of fluid and therefore could promote capillary haemostasis and progressive wound healing by optimal tissue contact [4]. Reservations prompted by drainage include the fact that it also prolongs operation time and increases costs, while itself constituting a source of infection [5]. Specific complications include accidental suturing of the tube or haemorrhage from a neighbouring blood vessel on removal. More importantly, modern surgery uses routine potent antibiotic prophylaxis [6] and improved skin disinfection. Operation times for caesarean section have also shortened markedly. In the absence of specific studies performed in this transformed surgical environment, we decided to test the efficacy of wound drainage after caesarean section in a prospective randomised trial under standardised modern operating conditions. Aim of the study: A prospective randomized controlled trial to determine the benefit of caesarean wound drainage in 305 low-risk pregnant women. Methods: Pregnant women at low risk of haemorrhage undergoing caesarean section in the Department of Obstetrics,University Hospital, Zurich, between June 1998 and July 1999 were randomised after informed consent into a no-suction group (n = 154) without post-caesarean wound drainage versus a control group with wound drainage (subfascial and subcutaneous) (n = 151). Outcome measures were perioperative decrease in haemoglobin (Hb), postpartum fever (>38.5 °C for >2 days), sonographic haematoma and other complications requiring revision, cumulative opiate dose adjusted to body weight, length of hospitalisation and operation time. Results: 305 patients completed the study. Decrease in Hb and the rates of fever, haematoma and revision were similar in both groups. However, cumulative opiate dose was lower in the no-suction group (4.5 ± 1.8 vs 2.8 ± 1.4 injections, p = 0.0001), and hospital stay was shorter (6.5 ± 2.4 vs 7.4 ± 2.8 days, p = 0.0058), as was operation time (32.7 ± 11.3 v 36.1 ± 10.5 min; p = 0.0071). Conclusions: Routine post-caesarean wound drainage is not only useless but cost-ineffective. In the light of our results, wound drainage may be questioned and should be analysed generally.