All 4 faces pain scales were found to be adequately supported by psychometric data .
When given a choice between faces scales , children preferred the WBFPRS .
Confounding of pain intensity with affect caused by use of smiling and crying anchor faces is a disadvantage of the WBFPRS .
: For clinical use , we found no grounds to switch from 1 faces scale to another when 1 of the scales is in use .
CONTEXT : Numerous faces scales have been developed for the measurement of  pain intensity in children .
It remains unclear whether any one of the faces scales is better for a particular purpose with regard to validity , reliability , feasibility , and preference .
OBJECTIVES : To summarize and systematic ally review faces pain scales most commonly used to obtain self-report of pain intensity in children for evaluation of reliability and validity and to compare the scales for preference and utility .
The effective time and concentration of nitrous oxide to reduce venipuncture pain in children.
STUDY OBJECTIVE To investigate the time of administration and concentration of inhaled nitrous oxide ( N(2)O ) needed to reduce the pain associated with intravenous ( i.v . ) cannulation in children . DESIGN Prospect i ve , r and omized study . SETTING Operating room of a children 's hospital . PATIENTS 73 ASA physical status I and II children , aged 6 - 15 years , scheduled for elective day or non-day surgery . INTERVENTIONS Children were r and omly allocated to one of 4 groups prior to i.v . insertion of a 24-gauge catheter in the dorsum of the h and : Group 1 ( n = 18 ) : 50 % N(2)O in O(2 ) for three minutes ; Group 2 ( n = 18 ) : 50 % N(2)O in O(2 ) for 5 minutes ; Group 3 ( n = 18 ) : 70 % N(2)O in O(2 ) for three minutes ; or Group 4 ( n = 19 ) : 70 % N(2)O in O(2 ) for 5 minutes . MEASUREMENTS Just after the venous cannulation , degree of pain was assessed by examining the faces of the patient by the parent and an operating room nurse . MAIN RESULTS Pain scores obtained from parents of children in Groups 3 and 4 were significantly lower than from those in Groups 1 and 2 . Pain scores from the nurse in Group 3 was significantly lower than those in Group 1 . However , there was no significant difference in pain score between Group 3 and Group 4 . Frequency of side effects was similar among the 4 groups . CONCLUSIONS Seventy percent N(2)O in O(2 ) given for three minutes was effective for reducing venipuncture pain in children
All 4 faces pain scales were found to be adequately supported by psychometric data .
When given a choice between faces scales , children preferred the WBFPRS .
Confounding of pain intensity with affect caused by use of smiling and crying anchor faces is a disadvantage of the WBFPRS .
: For clinical use , we found no grounds to switch from 1 faces scale to another when 1 of the scales is in use .
CONTEXT : Numerous faces scales have been developed for the measurement of  pain intensity in children .
It remains unclear whether any one of the faces scales is better for a particular purpose with regard to validity , reliability , feasibility , and preference .
OBJECTIVES : To summarize and systematic ally review faces pain scales most commonly used to obtain self-report of pain intensity in children for evaluation of reliability and validity and to compare the scales for preference and utility .