To our knowledge, this is the first randomised control study comparing the effects of music on sedation, analgesia and anxiety during radiological procedures
With the exception of pulse rate, the baseline characteristics, as well as other variables including the background morbidities and duration of procedures, were comparable between the two groups. As the baseline pulse rate was measured before the randomisation status was revealed, this difference must be a chance result.
Significantly fewer patients in the music group required any sedation than the controls (p
=0.046). This is because patients undergoing some interventional procedures, such as varicocele embolisation or straightforward angioplasties, are not sedated as routine. The distributions of these cases are comparable between the two groups, so this should be an intervention (music) effect rather than a chance finding. The music group was also associated with a significantly lower dosage of midazolam sedation than the control group (p
=0.027). A meta-analysis by Tam et al [6
] exploring the effect of music on sedation during colonoscopy returned a similar decreased requirement for sedation in the music group. A possible explanation offered is that patients listening to familiar music are more relaxed and so require a lower sedation dose. Koch et al [7
] suggested a relationship between auditory stimuli and stress response. The relative exclusion of ambient noise (auditory stimuli) contributes to the lower doses of sedation and analgesia required. The mode of action may be physiological or psychological, but playing music of the patient's choice during the IR procedure decreases the need for sedation and contributes favourably to patient experience.
There are a number of studies reporting positive effects of music on pain [7
]. The mechanism is not fully understood. One hypothesis is that positive emotional valence contributes to music-induced analgesia. Another, as discussed above, involves the relationship between auditory stimuli and stress. Although in our study lower mean (18 vs
26 μg) and median (0 vs
20 μg) fentanyl doses were also recorded in the music group, this intervention effect marginally failed to reach statistical significance. Similarly, a non-significant intervention benefit was seen with respect to the numbers of patients requiring any analgesia.
It is difficult to assess patient anxiety states during IR procedures objectively. In this study, anxiety states were measured prior to and after the IR procedure using a simple and objective questionnaire—the SAI. This is based on Speilberger's SAI [10
], which is a validated 20-item anxiety questionnaire. The scores range from 20 to 80, with higher scores suggesting higher anxiety levels. The patients in the study completed this independently without any help from any member of staff or their family. Patients in both groups returned higher pre-procedure than post-procedure SAI scores. This is intuitively expected with any surgical or IR procedure, as the patients are likely to be more anxious before the procedure than afterwards. In our study there were no significant differences between the music and the control groups.
Average pulse rate and average mean blood pressure were taken as surrogate markers of patient anxiety [10
]. Whilst these are reliable indicators of anxiety, they are influenced by both the sedative as well as the analgesic [11
]. The results demonstrate a higher mean pulse rate change and mean blood pressure change in the control group than in the music group (). Whilst not statistically significant, this should be interpreted against the background of higher sedation and so physiological lowering of the parameters in the control group. Given this, the change of the mean pulse rate and mean blood pressure in the control group is likely to be higher. This supports a possible anxiolytic effect of music [12
This study has been performed in the setting of an IR radiology suite. However, the factors involved are generic to any invasive procedure performed under conscious sedation, be it within radiology such as ultrasound/CT-guided procedures or in other clinical areas such as minor surgeries and endoscopy [14
]. The findings can be extrapolated.
Limitations of the study
This is a small, single-centre study. The small numbers limit the ability to draw meaningful conclusions from any of the subset analyses. Patients who did not bring their own music had to be offered a choice from the hospital collection, which was limited. The administration of conscious sedation was pragmatic and clinically guided. A more objective parameter, such as the bispectral index, was not used [15