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Background: Peripheral intravenous (i.v.) cannulation is a painful, frequently performed ED procedure. It is common practice in other medical settings to offer analgesia prior to cannulation., Objective: The present trial aims to reproduce in the ED studies that found a reduction in the pain of i.v. cannulation after intradermal lignocaine, ethyl chloride topical spray and entonox (50:50 oxygen : nitrous oxide). It also intends to determine which is analgesic most effective and explore the role of entonox for cannulation analgesia., Methods: Three hundred subjects were randomized into four groups: i.v. cannula inserted with (i) no anaesthesia; (ii) entonox; (iii) ethyl chloride; and (iv) 0.1 mL intradermal 1% lignocaine. Pain was recorded on 100 mm visual analogue scales (VAS) after lignocaine injection or ethyl chloride spray and following i.v. cannulation. A clinically significant reduction in VAS pain score was determined to be 13 mm., Results: Patients cannulated without analgesia reported the most pain. Those cannulated after lignocaine had the least pain (median VAS 20 mm, 95% CI 15-25, vs 1 mm 95% CI 0-6, P < or = 0.001). Ethyl chloride (VAS 11 mm, 95% CI 7-15, P = 0.003) and entonox (VAS 13 mm, 95% CI 8-18, P = 0.047) reduced i.v. cannulation pain but did not reach clinical significance. Neither pain from presenting symptoms (P = 0.3), nor size of cannula (P = 0.8) affected pain scores. VAS scores were independent of sex and age (P = 0.1). Cannulation success was not affected by either the choice of analgesia or cannulation site., Conclusions: The present trial confirms the findings of Harris and colleagues that lignocaine reduces the pain of cannulation in the ED. Lignocaine reduced the pain of i.v. cannulation more effectively than entonox or ethyl chloride.

A 30-year-old white male was found dead in a locked apartment with a rag held loosely in his mouth. Four cans (3 empty, 1 partially empty) containing ethyl chloride and labeled as VCR head cleaner were found next to the body. Phenylpropanolamine and low therapeutic levels of diazepam (64 microg/L) and nordiazepam (126 microg/L) were detected during toxicological analysis. An unidentified peak was observed when performing ethanol analysis by headspace gas chromatography. The peak was identified as ethyl chloride and the concentrations in the blood, urine, vitreous, brain, and lungs of the deceased were 423 mg/L, 35 mg/L, 12 mg/L, 858 mg/kg, and 86 mg/kg, respectively. The results were compared with previously reported levels of ethyl chloride in blood and vitreous and, based on a literature search, we believe that this is the first report of ethyl chloride levels in tissue.