Michiels 1990.

Methods	RCT Setting: hospital, Belgium
Participants	n = 40 (A) 20 (10 men, 10 women) (B) 20 (10 men, 10 women) Age: 3 to 89 years Infected post surgical wounds, oozing, covered in pus and debris Patients all gave informed consent Inclusion criteria: patients hospitalised in the surgical unit presenting with infected postoperative wounds, covered in pus and debris Surgery: ranged from osteosynthesis, microsurgery, reconstructive procedures; surgical site not reported Exclusion criteria: patients with diabetes, vascular insufficiency, severe anaemia and serum albumin less than 30 g/L
Interventions	Duration of the trial was 12 days (A) Dressing changed daily: wound cleansed ‐ no details of the technique given; a saline‐soaked compress was applied and this was covered by a 3 mm layer of dextranomer paste, covered with a compress and bandaged (B) Dressing changed daily; wound cleansed; then a gauze dressing soaked in 10% aqueous polyvinylpyrrolidone was applied, covered with a dry dressing and bandaged Further changes of the dressings for groups A and B were dictated by the degree of soakage of the dressings
Outcomes	Primary outcomes: (1) Time to a clean wound bed ‐ changes evaluated using specific variables; degree of erythema; degree of pus and debris; oedema; necrosis; granulation tissue. The results for each variable were assessed subjectively and presented individually Degree of erythema (reported using a 0 to 3 degree table): no significant difference reported (2 wounds in group A and 2 in group B did not have any erythema and were excluded from the evaluation of this variable) Oedema (reported using a 0 to 3 degree table): no significant difference (2 wounds in group A and 2 in group B did not have any oedema and were excluded from the evaluation) Necrosis (reported as a percentage of the total area of the wound): no significant difference (4 wounds in group A and 10 in group B did not exhibit any necrotic material and were excluded from the evaluation) Pus and debris (reported as a percentage of the total area of the wound): (1 wound in group B did not have any pus or debris and was excluded from the evaluation) No significant difference between the days of treatment or cleaning of the wounds. However, the trial also reported a further division of group A and B for evaluation of this variable, but it was unclear as to when this division was made and the handling and reporting of the data was unclear, subjective and the groups were not comparable at baseline. So while the subgroup of group A showed a higher degree of improvement in the removal of pus and debris and this was reported as significant (P < 0.05, Student's t‐test) the poor handling and subjective nature of the data makes this outcome unreliable. The subgroup of group B did not demonstrate a significant difference Granulation tissue: Mean time to a clean wound bed (SD not reported): (A) mean 6.5 days (B) mean 5.2 days No significant difference (1 wound in group A and 2 in Group B did not have any granulation tissue by the end of the trial and were excluded from the evaluation) (2) Time to complete healing: not reported Secondary outcomes: (1) Patient satisfaction: not reported (2) Rate of infection: not reported (3) Quality of life: not reported (4) Length of hospital stay: not reported (5) Cost‐effectiveness: not reported (6) Adverse events: 1 patient in group B had an allergic reaction with oedema and erythema after 10 days and the treatment was discontinued
Notes	The development and testing of the comparison tables was not reported, therefore it is not possible to determine the reliability and validity of these tables. While the mean days for granulation tissue was reported, no other data or statistics were presented
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The patients were allotted to one or other of the preparations according to a randomisation list" (p284)
Allocation concealment (selection bias)	Unclear risk	No details given about allocation concealment
Blinding (performance bias and detection bias) Participants and personnel	Unclear risk	Participants ‐ blinding not stated but blinding unlikely to influence outcome Personnel ‐ blinding not stated but unlikely to be achievable due to different properties (application of paste versus soaked dressings). Lack of blinding unlikely to influence results.
Blinding (performance bias and detection bias) Outcome assessors	Unclear risk	Outcome assessor ‐ blinding not stated, p284 states that the "status of the wound was recorded each day by the same doctor when the dressing was changed" but no further detail is given
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Of the 5 criteria to be reported on (granulation, pus and debris, erythema, oedema and necrosis) data are included within report on all 5 with missing data accounted for (for example within 'necrosis' 4 patients in one arm had no necrosis at the start or during so not reported) One patient in the control group exhibited an allergic reaction to treatment therefore treatment was discontinued (p288); it is not clear how this withdrawal was dealt with in the data presented
Selective reporting (reporting bias)	Low risk	No study protocol available but expected outcomes reported States that "aim of study was to assess and compare the clinical effects of dextranomer paste and a control treatment with polyvinylpyrrolidone (PVP) in a trial of patients with infected post‐operative wounds. All variables dealing with cleansing, inflammation reducing effect, and different signs of ongoing healing were studied" (p284). Reporting of granulation, pus and debris, erythema, oedema and necrosis is given within the report.