Journal of Research in Medical Sciences1735-1995232201802241075610756EN20180224<span class="fontstyle0">Background: </span><span class="fontstyle2">Renal colic is a painful medical emergency, needs urgent intervention to reduce pain. Nonsteroidal anti?in?ammatory drugs, opioids, and entonox are pain?relieving agents. Tis study was aimed to compare fentanyl + entonox (nitrous oxide + O</span><span class="fontstyle2" style="font-size: 5pt;">2</span><span class="fontstyle2">) versus fentanyl + oxygen. </span><span class="fontstyle0">Materials and Methods: </span><span class="fontstyle2">One hundred and twenty patients with acute renal colic presenting to the emergency department were enrolled. First, 50 </span><span class="fontstyle3">µ</span><span class="fontstyle2">g fentanyl was infused for all patients. Ten, patients divided into two groups receiving masks of entonox and oxygen, respectively. Quantitative  measurement of pain was performed by visual analog scale, before the intervention, after 3, 5, 10, and 30 min of that. If the pain was not relieved after 30 min, 50 </span><span class="fontstyle3">µ</span><span class="fontstyle2">g fentanyl was infused. If the pain was still continued,<br />ketorolac and ketamine were used. Hospitalization duration and severity of pain at specifed times were compared between patients in two groups. </span><span class="fontstyle0">Results: </span><span class="fontstyle2">Te mean (standard deviation) time of hospitalization was 211 (59) and 236 (61) min in fentanyl + entonox and fentanyl + O</span><span class="fontstyle2" style="font-size: 5pt;">2 </span><span class="fontstyle2">groups, respectively (</span><span class="fontstyle4">P </span><span class="fontstyle2">= 0.024). Te decrease in pain severity after 10 and 30 min in fentanyl + entonox group were signifcantly greater than fentanyl + O</span><span class="fontstyle2" style="font-size: 5pt;">2 </span><span class="fontstyle2">group (</span><span class="fontstyle4">P </span><span class="fontstyle2">= 0.002 and 0.001, respectively). Mean (standard error) of needed time for renal colic pain to get better was 11.27 (1.23) and 20.47 (1.71) min in fentanyl + entonox and fentanyl + O</span><span class="fontstyle2" style="font-size: 5pt;">2 </span><span class="fontstyle2">groups, respectively (</span><span class="fontstyle4">P </span><span class="fontstyle2">&lt; 0.001). Proportion of patients relief from pain in fentanyl + entonox in the second, third, and fourth measurements were signifcantly more than fentanyl + O</span><span class="fontstyle2" style="font-size: 5pt;">2 </span><span class="fontstyle2">group (</span><span class="fontstyle4">P </span><span class="fontstyle2">= 0.036, </span><span class="fontstyle4">P </span><span class="fontstyle2">&lt; 0.001, and </span><span class="fontstyle4">P </span><span class="fontstyle2">&lt; 0.001, respectively). </span><span class="fontstyle0">Conclusion: </span><span class="fontstyle2">Entonox is more e?ective to decrease the duration of hospitalization and reduction of pain than O</span><span class="fontstyle2" style="font-size: 5pt;">2 </span><span class="fontstyle2">in renal colic <span class="fontstyle0">patients</span> <br style="font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;" /></span> <br style="font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;" />http://jrms.mui.ac.ir/index.php/jrms/article/view/10756http://jrms.mui.ac.ir/index.php/jrms/article/download/10756/5597