| Methods |
Design: three group parallel trial in five sub‐studies
Purpose: examine the effect of transcutaneous electrical nerve stimulation (TENS) on acute postoperative pain |
| Participants |
Patients: postoperative in‐patients after thoracotomy
Baseline comparability: yes (sex and age) |
| Interventions |
Placebo: TENS without batteries
Untreated: no TENS
Experimental: TENS with batteries
(Co‐intervention: analgesics on demand, see outcome) |
| Outcomes |
Pain (overall analgesic medication within 12 hours) |
| Notes |
The results from five sub‐studies have been pooled |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Unclear risk |
NS |
| Allocation concealment? |
Unclear risk |
NS |
| Blinding?
Treatment provider |
Unclear risk |
NS |
| Blinding?
Outcome assessor |
Unclear risk |
NS |
| Incomplete outcome data addressed?
All outcomes |
High risk |
Drop‐out > 15% or NS |
| Free of selective reporting? |
Unclear risk |
No protocol available |
| Free of other bias? |
Low risk |
|
| No signs of variance inequality or skewness? |
Low risk |
No variance inequality (F‐test not statistically significant) and no skewness (1.64 standard deviations does not exceed the mean) |
| Trial size > 49? |
Low risk |
N = 221 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Drop‐out > 15% or NS |
