ShotBlocker versus cryotherapy for reducing pain and anxiety associated with subcutaneous injection

Injections have been a preferable method for administering drugs to achieve the desired effect directly and rapidly. Subcutaneous injections, in which the medication is released into the fatty layer of subcutaneous tissue completely below the skin, are among the various methods for injecting drugs.¹

The subcutaneous route permits drugs like heparin and insulin to be absorbed gradually over a period of time. Choosing the correct place and proper method for injection helps to diminish the risk of complications.²

Different types of drugs can be administered through the subcutaneous route, which has rapid onset of action and high bioavailability. However, pain sensation at injection site might reduce patient adherence with medication. Over the previous years, several studies have explored the effect of diverse methods for reducing pain related to injection, such as patient posture, injection speed, manual pressure, acupressure, 2-needle technique, needle temperature, z-track, cryotherapy, and ShotBlocker.³

Cryotherapy, the nomenclature of which originates from the Greek word Cryo, refers to restoration using extremely low temperatures. This type of therapy aims to reduce pain, inflammation, spasm, and hematoma formation at place of injection.⁴ Also, low temperature has an effect on sensory nociceptors through decreasing in the conduction time and synaptic activity in peripheral nerves; this may minimize the intensity of pain. Lowering the temperature of the nerves has been found to reduce sensory and motor conduction velocities, thereby reducing pain intensity.⁵

A ShotBlocker is a flexible plastic disk consisting of a large opening that is used during drug administration, with multiple skin contact points that are short and non-squeaky. This instrument is a novel application for pain intervention based on the gate control theory. During drug administration, ShotBlocker is put on the injection site, while non-sharp skin contact points are fixed promptly over the skin at the injection site and the medication is administered through a large opening.⁶ ShotBlocker is pressed on the surface of skin during injections. It is designed to reduce pain by stimulating nerve endings faster as a result of application of pressure from rounded nubs that are present on the device. This stimulation decreases pain by blocking pain signals temporarily during injections and by inhibiting the central nervous system.⁷

Nurses have an important role in minimizing the degree of discomfort sensation and pain during any invasive procedure, together with ensuring appropriate preparation and administration of drugs. Usage of proper methods during subcutaneous injection can reduce pain, anxiety, and other complications.⁸

Poor management methods for repeated subcutaneous injections have led to more pain and anxiety. Given that pain is one of the most common causes of human suffering, its management has been highly prioritized in nursing care. One of the most important responsibilities of nurses is the accurate and safe administration of medication to reduce pain, hematoma formation, and bruising.¹¹ The essential source of anxiety for patients receiving injection is needle pain, with fear possibly intensifying the perceived pain. The present study had been conducted to evaluate the effects of ShotBlocker and cryotherapy in reducing pain and anxiety during subcutaneous injections.

Concerning socio-demographic data, over half of our studied participants were female, which contrasted with the results of El-Deen and Youssef,¹² who showed that about two-thirds of the study participants were male. However, Emel et al.’s study¹³ found that the majority of study participants were female. Regarding age, slightly less than three-quarters of the studied sample were aged over 40 years, which was consistent with the results of El-Deen and Youssef,¹² who found that more participants were aged between 39 years and 59 years. On the other hand, in the study of Aydin and Avsar,¹⁴ it was demonstrated that more than half of the participants were aged between 18 years and 28 years.

A large proportion of the participants included in the present study were married. This is in accordance with the conclusions drawn in the study of Celik and Khorshid,¹⁵ who found that the majority of the studied participants were married. The findings of present study emphasized that over and above half of the participants undertook manual work, which may be related to the high prevalence of unemployed females who came from rural areas. However, Elsaid and Abdelkhalek¹⁶ reported that the majority were professionals and housewives. Regarding educational level, less than half of those in group I were illiterate, whereas the same percentage of those in group II had completed secondary school. This may be related to the fact that the majority of the study subjects came from rural areas with poor socioeconomic status and had low education levels. Meanwhile, the study by El-Deen and Youssef12 stated that over half of the participants in both their studied groups were educated.

Alabdalhai et al.¹⁷ reported that the mean duration for starting subcutaneous injection was M ± SD=6.6 ± 2.1. The present study detected that more than three-quarters of those in group II and all participants in group I had started subcutaneous injection since less than 1 year earlier. Moreover, our results showed that less than three-quarters of those in group II and a majority of those in group I feared subcutaneous injections. Furthermore, the most common medication used in both the groups was anti-coagulant.

Regarding injection site, over half of those in the cryotherapy and ShotBlocker groups (59.3 and 51.9%) received injections into the arm and abdomen, respectively. Meanwhile, a study by Alabdalhai et al.17 illustrated that over three-quarters of the patients received injections into the right thigh.

According to research hypothesis and results, a statistically significant reduction in the mean score of pain and anxiety levels was prevalent while using cryotherapy during the second injection rather than the first. Moreover, Taghlili et al.¹⁸ reported that the use of cold compress during subcutaneous injection of enoxaparin sodium could significantly decrease pain at the injection site. Similarly, El-Deen and Youssef¹² proved that the application of cryotherapy before and after subcutaneous injection had a great effect on reducing occurrence of hematoma and pain.

The blunt points of ShotBlocker are designed for physical stimulation, which may have an impact on pain perception. ShotBlocker causes pressure over skin through these blunt points, thus leading to rapid stimulation of small nerve endings. This stimulation stops pain signals during injection and decreases pain sensation by closing the gates of pain perception to the central nervous system.¹⁹ Such an explanation would be in conformity with the results of the present study, which showed a significant difference in pain levels between the conventional injection technique during first injection and ShotBlocker during second injection.

This finding supports those drawn in Sahiner et al.’s study,²⁰ in which it was reported that the pain levels decreased when using ShotBlocker during insulin injection in children with type 1 diabetes.

Finally, the present study found a statistical difference in the level of anxiety in the 2 groups during the second injection, which was consistent with the findings of Girgin et al.,²¹ who illustrated that the post-procedure fear scores for the ShotBlocker group were lower than that for the control group. Similarly, Sahiner et al.20 found a significant difference between the groups in terms of procedural anxiety levels reported by the family and observer, favoring the intervention groups using ShotBlocker.