Figure 7From: Effects of Parecoxib and Fentanyl on nociception-induced cortical activity The effect of fentanyl on heart rate and respiratory rate. The two upper panels show examples of heart rate and respiratory rate recordings. The left, lower graph shows that fentanyl did not alter heart rate. The right, lower graph shows that fentanyl had a small but significant effect on respiratory rate. *P < 0.05.Back to article page