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Thomson et al reported the first double blind placebo controlled study of intrapleural urokinase for the treatment of childhood empyema.1 They found a statistically significant reduction in hospital stay in the treatment group and concluded that “urokinase is a successful adjunct to the management of parapneumonic empyema”.
The primary management of childhood empyema is controversial with some groups advocating open decortication.2 However, because of reports of wound infection, air leaks and bleeding in open decortication, there has been an increase in the potential for video assisted thorascopic surgery (VATS) as primary treatment for childhood empyema.3 We have recently reported our experience in 21 children undergoing primary VATS for empyema between September 2000 and September 2001.4 The mean (SE) length of stay in hospital was 7.6 (1.2) days, which is comparable to that in the study by Thomson et al (7.4 days). Importantly, no child went on to open decortication; in Thomson’s study five of 58 patients went on to surgery. This reflects our own experience of a failure rate with urokinase treatment approximating 10–15%. We have recently undertaken VATS in six children referred to our centre for further management following the failure of urokinase treatment. Five were successfully treated with VATS but one proceeded to open decortication. Urokinase causes the intrapleural loculations to become very adhesive and increases the difficulty of the VATS procedure. Thus, urokinase is likely to increase the chances of a child undergoing open decortication in those who fail medical treatment.
There may be a role for urokinase in early empyema (although this was not specifically studied by Thomson et al), and it is likely that VATS is more useful in stages 2 and 3. We call for studies to examine prospectively the primary treatment of choice in childhood empyema and, to this end, we have recently embarked on a randomised prospective study to compare primary VATS with urokinase and chest drain in childhood empyema.
We are pleased that Sit et al are interested in our controlled trial. We do not doubt that video assisted thoracoscopic surgery (VATS) will have a role in a limited number of patients with empyema, but do not consider it first line treatment. The major limitation of VATS is that it is highly dependent on the skill of the operator and poor results in some centres were reported at the recent American Thoracic Society meeting. Good paediatric practitioners will be limited to a few major centres in the UK.
One of the strengths of our study was that we obtained excellent results using urokinase in a multicentre trial with very variable previous experience of the technique. Sit and colleagues should note that, of the five patients who had surgery in our study, three were in the control group; the need for surgery in the urokinase group was therefore only 6.6%. Our single centre experience (Oxford) of 69 consecutive patients with empyema treated with urokinase is a median post intervention length of hospital stay of 5 days (range 3–13) with only one patient needing surgical intervention (1.5%). These data should be useful in the power calculations needed before a comparative randomised trial of VATS versus urokinase is commenced.