title: Randomized controlled trial of cryoanalgesia (ice bag) to reduce pain associated with arterial puncture.
abstract: BACKGROUND
  Arterial puncture can be a painful procedure for many patients. This study investigates whether precooling of a puncture site with ice can reduce the pain associated with arterial puncture.
  
  
  METHODS
  This was a stratified randomized controlled trial of a convenience sample of out-patients with a physician order for an arterial blood gas (ABG) test. The intervention group had a plastic bag of ice applied to their wrists for 3 min before drawing an ABG sample from the radial artery. The control group had an ABG sample drawn from the radial artery without the application of ice. Pain from the arterial puncture was measured with a 100-mm visual analog scale.
  
  
  RESULTS
  Subjects pretreated with ice reported less pain from arterial puncture compared with subjects in the control group (mean visual analog scale 13.8 ± 16.9 vs 25 ± 23 mm, P = .01; median visual analog scale 7 mm, interquartile range (IQR) 1.5-19 vs 20 mm, IQR 4.5-38.5 mm, P = .01). Stratified analysis showed that visual analog scale pain scores were lower in the naive group when ice was applied (naive ice vs naive control: mean visual analog scale 11 ± 14.3 vs 26.5 ± 25 mm, P = .02; median visual analog scale 5 mm, IQR 2-14.5 vs 20 mm, IQR 6.5-36 mm, P = .02). Visual analog scale pain scores trended lower in the experienced group when ice was applied (experienced ice vs experienced control: mean visual analog scale 15.9 ± 18.9 vs 25.1 ± 22 mm, P = .15; median visual analog scale 8 mm, IQR 0.5-26.5 vs 23 mm, IQR 3.5-40 mm, P = .08). There was no difference in first-attempt success between groups (ice group: 85%, control group: 82.5%, P > .99). Only 3 subjects could not tolerate 3-min ice application.
  
  
  CONCLUSIONS
  Ice application before arterial puncture is well tolerated and reduces procedure-related pain. (ClinicalTrials.gov NCT02065115).
authors.affiliation: Pulmonary Function Laboratory, St Joseph Hospital, Nashua, New Hampshire. jhaynes@sjhnh.org.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Haynes
mesh_terms: D000368:Aged; D000698:Analgesia / Q000379:methods*; D001784:Blood Gas Analysis; D017679:Cryotherapy; D005260:Female; D006801:Humans; D007053:Ice; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D010147:Pain Measurement; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D011677:Punctures / Q000009:adverse effects*; D017534:Radial Artery / Q000601:surgery*
chemical_list: D007053:Ice
keywords: cryotherapy; ice; pain; puncture