Spiced RCT: Success and Pain Associated with Intravenous Cannulation in the Emergency Department Randomized Controlled Trial

J Emerg Med. 2024 Feb;66(2):57-63. doi: 10.1016/j.jemermed.2023.10.008. Epub 2023 Oct 16.


Background: Peripheral venous cannulation is one of the most common procedures in medicine. A larger cannula allows higher rates of fluid to be provided if needed in a deteriorating patient; however, it is also perceived that larger-gauge cannula placement is associated with increased pain and procedural difficulty.

Objective: This study aimed to compare the pain and procedural difficulty experienced during insertion between 18-gauge (18G) and 20-gauge (20G) cannulas.

Methods: We conducted a single-blinded, randomized controlled trial on adult patients who required peripheral IV cannulation within a tertiary hospital emergency department between April and October 2018. Patients were randomized to either the 18G or 20G cannula group. The primary outcomes of the study-pain experienced by patients and procedural difficulties experienced by clinical staff-were recorded on two separate 10-cm visual analog scales. Other outcomes include first-attempt success rate, operator designation, complications, and the intent and actual use of the IV cannula were documented on preformatted questionnaires.

Results: Data from 178 patients were included in the analysis. Eighty-nine patients were allocated to each cannula group. There were no statistically or clinically significant differences between mean pain score (0.23; 95% CI 0.56-1.02; p = 0.5662) and mean procedural difficulty score (0.12; 95% CI 0.66-0.93; p = 0.7396). between the two groups. There was no difference in first-attempt success rate (73 of 89 vs. 75 of 89; p = 0.1288), complications (2 of 89 vs. 1 of 89) between the 20G group and 18G group, respectively.

Conclusions: There was no significant difference between the 18G or 20G cannula for either pain experienced by patients or procedural difficulty experienced by clinicians.

Keywords: cannula size; cannulation; pain; procedural skills difficulty; randomized controlled trial.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Cannula / adverse effects
  • Catheterization, Peripheral* / adverse effects
  • Catheterization, Peripheral* / methods
  • Emergency Service, Hospital
  • Humans
  • Pain Measurement
  • Pain* / etiology