Young 1982.

Methods	RCT Setting: hospital and outpatient clinic, UK
Participants	n = 50 (A) 25 (B) 25 Numbers of men and women not reported Mean age (years): (A) 44.48, SD 5.17 (B) 49.64, SD 4.57 Patients with surgical wound breakdown Consent not reported Inclusion criteria: patients undergoing surgery for perforated or gangrenous appendix, where the wound was left open from the muscle layer outwards; patients with surgical wound breakdown postoperatively No exclusion criteria listed
Interventions	Each wound was measured at the start of the trial: Mean length (cm): (A) 5.53, SD 0.55 (B) 6.57, SD 0.89 Mean breadth (cm): (A) 2.25, SD 0.33 (B) 2.48, SD 0.32 Mean depth (cm): (A) 1.80, SD 0.20 (B) 2.24, SD 0.29 Mean volume (ml): (A) 4.92, SD 1.15 (B) 6.37, SD 1.30 Individual wounds were photographed All wounds were initially treated with gauze packing for the first 48 hours (A) Dextranomer beads applied twice‐daily: reduced to once a day when the discharge reduced (B) Silastic foam dressing applied, and this was removed and cleaned twice a day; reduced to once a day with reduction in the discharge All wounds were reviewed on 1st, 3rd and 7th days and then weekly. Patients discharged home had their wounds reviewed weekly The review included: photograph, measurement of the wound, review of erythema, oedema, rash, odour and slough Comfort of the dressing was assessed by questioning the patient Pain was graded using an ordinal scale (0 = no pain to 3 = severe pain)
Outcomes	Primary outcomes: (1) Time to disappearance of erythema, oedema and slough: similar in group A and group B; data and statistics not reported (2) Mean time to complete healing (days): (A) 40.92, SD 3.98 (B) 36.96, SD 3.18 Results subjected to analysis using the Student's t‐test Secondary outcomes: (1) Patient satisfaction: mean days until pain free dressings (A) 5.32, SD 0.55 days (B) 5.64, SD 0.45 days Results subjected to analysis using the Student's t‐test Wound pain reported as similar for both groups (2) Rate of infection: not reported (3) Quality of life: not reported (4) Length of hospital stay: not reported (4) Cost‐effectiveness: authors quoted the costs as calculated in a previous study (Goode 1979): (A) Approximately £3.40 per day (B) Approximately £0.75 per week; no data or statistical evidence reported (6) Adverse events: not reported
Notes	An ordinal scale is used to assess the pain at dressing changes. This may result in skewed data, so a non parametric Mann‐Whitney U‐test may have been more appropriate than the Student's t‐test. Also there was a methodological flaw in the analysis of the data and time to complete healing and time to a pain‐free wound, which should have been expressed as a hazard ratio and not as continuous data.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Patients were allocated to receive either Debrisan or Silastic foam elastomer by means of a random card system" (p33). Not clear if the cards were randomised. However, the method used for generating the randomisation sequence for the cards was not reported. Hence, it was judged to be unclear.
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not stated
Blinding (performance bias and detection bias) Participants and personnel	Unclear risk	It is not reported if participants were blinded to treatment, however blinding would be unlikely to affect results. Blinding or not of personnel to treatment is not reported, however due to the different properties of the dressings this would be unachievable.
Blinding (performance bias and detection bias) Outcome assessors	Unclear risk	Limited information given within the paper: "wounds were reviewed" (p33) but it is not stated by whom and if they were blinded to the intervention
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow up reported, 50 patients completed the trial (25 in each arm)
Selective reporting (reporting bias)	Low risk	No study protocol is available but appropriate study outcomes reported The aim of the trial was to "compare the efficacy of these two dressings in surgical wounds that have either broken down or have been left open postoperatively" (p33). It is not stated how "efficacy" will be measured at the outset. Time to heal and time to pain‐free are reported within the trial; presence of erythema, odour, slough and rash were also reported.

A = intervention group
 B = control group
 ITT = intention‐to‐treat
 RCT = randomised controlled trial
 SD = standard deviation
 SEM = standard error of the mean