Abdulla 2012b.
| Methods | Double‐blind, placebo and active‐controlled, multiple dose, over 24 h First dose administered 15 min prior to extubation |
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| Participants | Type of surgery: laparoscopic cholecystectomy Paracetamol group Entered/completing: 30/30 Age (mean, SD): 52.5 ± 15.8 Sex (male, %): 23.3% Placebo Entered/completing: 30/30 Age (mean, SD): 47.1 ± 13.9 Sex (male, %): 20.0% Parecoxib Entered/completing: 30/30 Age (mean, SD): 54.9 ± 13.0 Sex (male, %): 26.7% Metamizole Entered/completing: 30/30 Age (mean, SD): 52.4 ± 15.6 Sex (male, %): 30.0% |
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| Interventions | 1 g paracetamol in 100 ml normal saline over 15 min Placebo, parecoxib 40 mg, or metamizole 1 g: all in 100 ml NS over 15 min |
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| Outcomes | Primary: accumulated opioid consumption (piritramide via PCA) Secondary: Pain intensity (VAS) Pain relief (VRS) Patient satisfaction (VRS) |
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| Source of funding | Not mentioned | |
| Were treatment groups comparable at baseline? | Yes | |
| Details of preoperative pain | Participants with chronic pain were excluded | |
| Notes | — | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Computer‐generated randomization (http://www.randomization.com) |
| Allocation concealment (selection bias) | Low risk | The group assignment code was retained until the conclusion of the study |
| Blinding (performance bias and detection bias) All outcomes | Low risk | “The study solutions were prepared by one of the researchers who were not involved in the intraoperative and postoperative treatment of these patients. Postoperative data were collected by anesthesiologists who were blinded as to the treatment used. Other caretakers were also unaware of the analgesic drug that would be used for each patient during the study”. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | No dropouts or protocol violations – complete data set obtained for all 4 groups |
| Selective reporting (reporting bias) | Unclear risk | All outcomes from Methods section reported in Results section, but side effects not monitored adequately and satisfaction score results not fully described |
| Size | High risk | Fewer than 50 participants per arm of the study (30 paracetamol, 30 placebo, 30 parecoxib, 30 metamizole) |