Paediatric Pain, Invasive Procedures and Virtual Reality: Preliminary Exploratory Research

The aim of the present exploratory and preliminary study was to evaluate the effectiveness of Virtual Reality as a non-pharmacological analgesic method in addition to the standard protocol of care in paediatric patients undergoing invasive medical procedures, in particular intravenous access. The sample of 18 children aged between 5 and 10 years was divided into an experimental group (exposed to virtual reality during the procedure) and a control group (subjected to the standard protocol). Participants in both groups were asked to report, by means of two self-report scales (Wong-Baker Pain FACES Scale and Children’s Fear Scale), the degree of pain and fear perceived both before and after the procedure. Finally, by means of a saturimeter attached to the finger, the physiological parameters (oxygenation and heart rate) observed before, during and at the end of the procedure were recorded.

The video projected via the virtual reality visor consisted of the viewing of a cartoon, with sound but no speech, with a total duration of approximately three minutes.

Regarding the results, little significant data emerged regarding the effectiveness of using virtual reality as a non-pharmacological analgesic treatment for pain induced by medical needle procedures, but certainly interesting as future clinical and research suggestions.

Keywords: virtual reality; pain; child.

Anticipatory fear and anxiety are common during invasive medical procedures in paediatric patients (Ollendick, 1983), to such an extent that they are more likely to experience more pain and distress during actual procedures (Blount, Piira, Cohen, 2003; Blount, Sturges, Powers, 1990). In this regard, needle pain is the most common type of procedural pain and causes many children considerable discomfort. Surveys have found that more than 50% of children and adolescents who undergo venepuncture for routine blood sampling experience moderate to severe levels of distress or pain (Fradet, McGrath, Kay, Adams, Luke, 1990). In most cases, these fears cause reluctance in children and also in their parents leading them to postpone, or even discontinue, some necessary tests, thus affecting the child’s care process in the future as well (Inal, Canbulat, 2015). It is therefore crucial that health professionals adequately assess and monitor the intensity of pain and provide timely and effective intervention to treat it. Intervening in this way will increase pain tolerance during subsequent interventions.

With reference to this, the WHO guidelines suggest various strategies, including cognitive and behavioural psychological approaches (WHO, 2010), the main objective of which is to divert attention from pain by selectively focusing it on stimuli that are different from or incompatible with it: this slows down and/or inhibits the processing of the sensory and affective components of pain. Consequently, this allows the child to reduce or even block the perception of pain. Among these, some studies have confirmed that the use of immersive virtual reality can alleviate pain and fear in children aged 7-19 years receiving invasive needle-based medical treatment (Gershon, et al., 2004; Gold, et al., 2006; Piskorz, Czub, 2018; Sander, et al., 2002; Wolitzky, et al., 2005).

A virtual reality system is a combination of hardware and software components that generate synchronised multisensory stimulation that draws participants’ attention away from the visual, auditory and tactile stimuli of the ‘real world’ and towards the ‘virtual world’. In addition, the presentation of a virtual environment via a head-mounted display prevents the visual perception of stimuli in the real world and thus offers additional advantages over other forms of distraction. This creates in the user the illusion of being physically in a three-dimensional space in which he/she can interact with the objects and agents in it (e.g., people, animals and imaginary characters) (Riva, Wiederhold, Mantovani, 2019; Bailenson, 2018).

2.1 Sample

The sample consisted of 18 subjects aged between 5 and 10 years (M_age = 6.725, SD_età = 1.515), divided into experimental and control group. The experimental group (n = 10, M_age = 6.70, SD_age = 1.64) consisted of 60% males (n = 6) and 40% females (n = 4). The control group (n = 8, M_età = 6.75, SD_age = 1.39), on the other hand, consisted of 37.5% males (n = 3) and 62.5% females (n = 5). These were children who, accompanied by a parent, had gone to the emergency department and day-hospital belonging to the paediatrics department of the Hospital dell’Angelo in Mestre, in the period between January and June 2023, for emergency consultations or planned surgery.

The children and their parents were approached in the waiting room of the ward, after which the objectives and modalities of the study were explained to them, followed by an explicit invitation to take part. If both consented, informed consent was signed and the child was shown how to use the two self-report scales. In addition, the children in the experimental group were shown the virtual reality visor and explained to them that they would watch a short video during the medical procedure.

In contrast, the subjects in the control group would follow the instructions of the nurses during the procedure. The parents remained with their children during both the data collection and the medical procedure. Both groups were also given a eutectic mixture of local anaesthetics (EMLA) half an hour to an hour before the procedure took place, as per the hospital’s standard care protocol.

2.2 Instruments

The fear and pain levels of participants in both groups were assessed both before and after the procedure.

For fear, the Children’s Fear Scale (CFS, McMurtry, Noel, Chambers, McGrath, 2011), a single-item self-report scale consisting of a row of five gender-neutral faces, was used. At the left end there is a face with no fear (neutral) while at the right end there is a face showing very strong fear (Fig. 1). The evaluator is asked to respond by indicating which of the five faces corresponds to the level of anxiety or fear experienced at that moment.

Figure 1: Children’s Fear Scale (CFS).

For pain, the Wong-Baker Pain FACES Scale (WBPFS, Wong, Baker, 1988) was administered, a single-item self-report scale consisting of six black-and-white stylised faces representing various degrees of pain, starting from the extreme left corresponding to ‘no pain’ to the extreme right indicating ‘worst possible pain’ (Fig. 2). The assessor is asked to respond by indicating which of the five faces corresponds to the level of pain experienced at that moment.

Figure 2: Wong-Baker Pain FACES Scale (WBPFS).

In addition, oxygenation and heart rate were monitored using a saturation meter attached to the patient’s finger.
In particular, the values observed at the start and end of the medical procedure, as well as at the time the needle was inserted, were transcribed.

Oxygenation represents the ratio between the oxygen present in the blood and the maximum amount of oxygen that can be transported from the blood to the organs and tissues. It indicates whether the lungs are functioning well and therefore the blood is being loaded with oxygen. Blood saturation values are normally between 95% and 100%. Heart rate (HR), on the other hand, is the rate of contractions, or pulsations, of the heart measured by the number of beats per minute (bpm). The normal heart rate for a child between 6 and 12 years old at rest is between 60-110 bpm.

Finally, with regard to the video projected through the virtual reality visor, it was a cartoon, with sound but no speech, with a total duration of about 3 minutes.

2.3 Hypothesis

Research by Chen and colleagues (2021) reports that the use of virtual reality helps to improve the psychological tension of the user. Furthermore, numerous studies have confirmed that the use of immersive virtual reality can alleviate the pain and fear of children between the ages of 7 and 19 years receiving invasive needle-based medical treatment (Gershon, et al., 2004; Gold, et al., 2006; Piskorz, Czub, 2018; Sander, et al., 2002; Wolitzky, et al., 2005). For these reasons, the fear reported by the experimental group at the end of the procedure was expected to be lower than that reported before the procedure. In contrast, this effect was not expected among the subjects in the control group. Furthermore, it was expected that the mean pain and fear scores reported by the patients in the experimental group at the end of the procedure would be lower than those reported by the control group.

Furthermore, heart rate has been used as a valid physical measure of discomfort in several previous studies (Jay, Elliott, Fitzgibbons, Woody, Siegel, 1995; Stark et al., 1989). Consequently, due to the positive effect of virtual reality on the pain and fear experienced by the children, it was expected that the heart rate measured at the end of the procedure in the subjects of the experimental group would generally be lower than the values measured in the pre-procedure.

In summary, the hypotheses characterising the present research work are:

Hypothesis 1: It is hypothesised that the fear reported by the experimental group at the end of the procedure is lower than that reported before the procedure;

Hypothesis 2: It is hypothesised to observe that the mean pain and fear scores reported by patients in the experimental group at the end of the procedure were lower than those reported by the control group;

Hypothesis 3: It is hypothesised to observe that the heart rate reported by subjects in the experimental group at the end of the procedure was generally lower than the values measured before the procedure.

The data were analysed using Jamovi 2.3 software.

Some interesting data emerged from the analysis of the descriptive statistics. In particular, with regard to fear, it appears that the mean reported before the start of the procedure is higher in the experimental group than in the control group (M_fearEG = 1.00 and M_fearCG = 0.500). It appears that in the experimental group, the data are more evenly distributed between the categories, whereas in the control group they predominantly lie at low values (0 and 1). Similarly, the fear reported at the end of the procedure remains, on average, at higher values in the experimental group (M_fear = 0.900) than in the control group (M_fear = 0.750). It can be seen, however, that it fell slightly in the experimental group between pre- and post-procedure, whereas it rose in the control group. In fact, looking at the data on a graphical level, in comparison to the pre-procedure, a greater distribution around the low values in the experimental group can be seen. Even in the control group, the prevalence of the data remains predominantly concentrated on low values, but the presence of a high value (4 points on the scale) also emerges, which therefore contributed to raising the average for the entire group.

With regard to the variable ‘pain’ it can be observed that the two averages referring to the pre-procedure were similar between the two groups (M_painEG = 0.400 and M_painCG = 0.500). On the contrary, at the end of the procedure it can be seen that in the control group the mean values decreased (M_painCG = 0.250), while in the experimental group they increased (M_painEG = 1.40). On a graphical level, it can be observed that in the experimental group in the post-procedure there is a greater distribution of the data between the categories, whereas in the pre-procedure they were predominantly concentrated around low values (Gr. 1).

Graphic 1: Distribution of data for the variable ‘pain’ pre- and post-procedure.

As far as oxygenation is concerned, on average, similar values are shown between the two groups both before (M_{oxygenationEG} = 99.2 and M_{oxygenationCG} = 99.5), during (M_{oxygenationEG} = 98.7 and M_{oxygenationCG} = 99.5) and at the end of the procedure (M_{oxygenationEG} = 97.9 and M_{oxygenationCG} = 99.5). However, when looking at the trend of the values over time, it can be seen that in the control group the mean remains stable, while in the experimental group it gradually decreases.

With regard to the heart rate, higher average values are noted in the control group both before (M_{heart rateEG} = 93.400 and M_{heart rateCG} = 106.00), during (M_{heart rateEG} = 101.00 and M_{heart rateCG} = 104.125), and at the end (M_{heart rateEG} = 94.800 and M_{heart rateCG} = 105.375) of the procedure. Furthermore, comparing the values measured in the experimental group in the pre- and post-procedure, a slight increase in the investigated parameter is observed (M_{heart rate-pre} = 93.400 and M_{heart rate-post} = 94.800).

In addition, four ANOVAs for repeated measures with mixed within- and between-subjects designs were conducted to investigate the treatment effect. Specifically, two 2×2 ANOVAs (for the variables ‘pain’ and ‘fear’) and two 2×3 ANOVAs (for ‘oxygenation’ and ‘heart rate’) were conducted. Only one statistically significant interaction effect between time and treatment was found on the variable ‘pain’ for a level of α set at < 0.05 (Gr. 2).

Graphic 2: Interaction between time and treatment on the ‘pain’ variable.

Finally, Pearson’s correlation analyses were conducted on the entire sample (without division between experimental and control) to explore the linear relationship between the variables detected. No correlation was found to be statistically significant at a level of α set at < 0.05.

Overall, the results show that the fear reported by the experimental group at the end of the procedure is slightly lower than that reported before the procedure. Therefore, the first hypothesis of the present study is confirmed. In this regard, it can also be observed that, on the contrary, in the control group the mean fear score at the post-procedure increased in comparison to the pre-procedure. It can therefore be assumed that this difference between the two groups can be attributed to the effect of the use of the virtual reality visor. Furthermore, similar values were observed between the two groups with respect to the pain measured at the pre-procedure.

On the contrary, at the end of the procedure in the experimental group the mean values are higher than in the control group. In addition to this, the comparison between the two groups reveals a statistically significant interaction effect between time and treatment on the variable ‘pain’, which indicates an increase in pain in the experimental group with the passage of time. This finding is in stark contrast to the second hypothesis of the present research, as it would seem to indicate that the use of the virtual reality visor contributed to an increase in the subjects’ perceived pain, not a decrease. To explain this, it could be hypothesised that the subjects in the experimental group actually became aware of the pain perception induced by the medical procedure only at the end of the procedure, i.e., when they were asked to report the degree of pain they were experiencing. In contrast, it is plausible that the control group, which was not distracted and thus aware throughout the procedure, began to have perceptual awareness of pain already during the insertion of the needle. Consequently, when the children in the control group were asked to report the level of pain they perceived at the end of the procedure, it had already begun to subside. This would therefore result in lower mean values at post-procedure in the control group than in the experimental group.

With regard to heart rate, the experimental group showed higher values at the end of the procedure than those measured before it. Consequently, the third and last hypothesis is also not confirmed. However, this is consistent with the results obtained in respect of pain. In fact, the literature shows that there is a positive relationship between heart rate and pain. In particular, Hilgard and colleagues (1974) examined the physiological response to pain in a small group of healthy people and found an increase in heart rate when individuals were exposed to noxious stimuli. In addition to this, the heart rate of the experimental group may also have been influenced by other variables, such as the possible arousal induced by the appearance of novelty and curiosity towards the virtual reality device.

As far as oxygenation is concerned, on average, similar values are shown between the two groups both before, during and at the end of the procedure. However, looking at the trend of the values over time, it can be seen that in the control group the average remains stable, while in the experimental group it gradually decreases. This finding, read in conjunction with the results on pain in the experimental group, is consistent with a study by Høiseth and colleagues (2015) showing a negative relationship between pain and oxygenation. Finally, Pearson’s correlation analysis on the entire sample (without division between experimental and control) showed no statistically significant correlation.

In conclusion, although no ‘strong’ significant results emerge with respect to the effectiveness of using virtual reality as a non-pharmacological analgesic treatment for pain induced by medical needle procedures, the present study offers useful insights for future investigations in this field.

First of all, an important limitation is the very low sample size, both with respect to the total sample and with respect to the two groups. In fact, at the design stage of the study, the G power was calculated to determine the sufficient sample size. It turned out that for a strong effect (F = .40), 18 to 20 subjects would have been required for each group, for a total of 36 to 40 children.

Furthermore, with respect to virtual reality, several critical points stand out. Firstly, for some subjects, the duration of the cartoon was excessively short, since the medical procedure lasted beyond the end of the projection. After the video had finished, in fact, the screen went dark, and for this reason, the children may have become even more agitated as they were unable to see what was happening to them. In future research, the use of more appropriate films in terms of duration and content is therefore recommended. Secondly, the source of distraction proposed to the experimental group consisted solely of the passive viewing of a video. In contrast, the literature states that virtual reality contributes more to pain reduction if the subject is actively involved, e.g., by performing tasks or exploring the virtual environment. However, it is important to point out that the medical procedure the participants underwent required general immobility of the patient.

Finally, the proposed film, despite having an acoustic component, was not spoken. On the one hand, this was an advantage, as more than half of the sample were foreign children, thus avoiding possible language misunderstandings; on the other hand, this may have resulted in less involvement.