Robinson 2007.
| Methods | Randomized controlled 4‐arm parallel trial in the emergency department of a tertiary hospital in New Zealand | |
| Participants | 300 patients, older than 15 years of age, triage 3 to 5, needing cannulation. Mean age 49 years (range 16 to 92 years). 50% female. "The four groups did not differ in their demographic makeup" Inclusion criteria included a Glascow coma scale score (GCS) = 15 and conversational English Excluded if unable to give consent because of intoxication or intellectual impairment, unable to complete the visual analogue scale because of disability (e.g. blindness, inability to hold a pen), patient refusal, needing emergency cannulation, possible bowel obstruction, pneumothorax, allergy to any of the trial drugs. Excluded if more than 2 attempts at cannulation |
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| Interventions | After standard preparation, randomized to 4 arms (number): Group 1: no anaesthesia (69) Group 2: Entonox inhaled for 1 minute before and during cannulation (77) Group 3: ethyl chloride sprayed for 5 to 10 seconds, 15 to 20 cm from intended site of cannulation (73) Group 4: 0.1 mL 1% lignocaine injected intradermally with a 26 gauge needle (71) |
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| Outcomes | Pain with application of lignocaine or spray, pain of cannulation, side effects | |
| Funding | None declared | |
| Notes | No treatment group used in analysis | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Random numbers were assigned to groups by the SAS computer program using random length blocking" |
| Allocation concealment (selection bias) | Low risk | "Sealed envelopes containing treatment instructions, data sheets and study information were opened only after the patient had given consent" |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Attrition described: 4 excluded for including more than 2 cannulation attempts; 6 excluded because of incomplete data |
| Selective reporting (reporting bias) | Unclear risk | Protocol not available, but all expected outcomes reported |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | No blinding |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | No blinding |