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I. Introduction
Needle-stick injuries (NSIs) are the most frequent occupational injuries experienced by healthcare providers (HCPs) around the world [1,2]. NSIs are dangerous because blood-borne pathogens in patients can infect HCPs [1,3]. In addition to affecting the health of HCPs, NSIs impose costs on HCPs and society because they necessitate examinations, treatment, and the loss of human resources [2,4,5].
Therefore, many efforts have been made to analyze the causes of NSIs and ways to reduce them. The main causes of NSIs can be classified as engineering-related factors (e.g., the form of sharp devices and barrier devices), organizational factors (e.g., the methods and policies for reporting), and behavioral factors (e.g., recapping and disposal) [2,6,7]. Safety devices have been used to prevent NSIs. Many interventional studies used safety syringes to reduce NSIs, and several types of needle destroyers have been designed to dispose of syringes [8,9]. However, only a few interventional studies using these devices have been conducted in a medical environment [10].
In this study, the researchers introduced a new needle-destroying device, called the Automatic Needle Destroyer (AND), which separates the needle from the syringe for disposal. We hypothesized that the AND would be beneficial in an emergency department (ED), where many syringes are used. Therefore, we evaluated the efficiency, safety, and usability of the AND in a real medical environment.
II. Methods
1. Overall Study Design
This was a mixed-methods interventional study using the AND invented by the MUNE Corporation (Seoul, Korea). This study was supported by a Bio/Healthcare Commercialization Support Program grant through the Incheon Center for Creative Economy and Innovation. The researchers conducted this study and had no conflicts of interest. The study protocol was approved by the Institutional Review Board of Samsung Medical Center (No. 2019-05-112-001). This study was registered at clinicaltrials.gov (Identifier: NCT04039906).
1) Setting
The study was conducted in an ED of a 1,989-bed tertiary academic hospital in Seoul. This department treats more than 70,000 patients annually and is evaluated as providing high-quality emergency care according to the national emergency patient care information network. Syringes and needles are disposed of according to the hospital’s standard procedure for dealing with biohazardous materials. The waste disposal process did not change when the AND was used.
2) Design
We designed this study to derive valid results from comprehensive and corroborative data obtained through quantitative and qualitative means.
This study was conducted over 3 weeks, including a pre-intervention week (the first week), a preparation week (the second week), and an intervention week (the third week) (Figure 1). We set each period to last for a week as it was difficult to apply the new system for a longer period in the complex ED environment. Furthermore, nurses’ duties changed weekly.
We designated 10 of the 15 candidate sites in the ED for testing. In the pre-intervention week, syringes were manually removed by the existing method without the AND. In the preparation week, AND systems were installed and instructions (in the form of a video description of the product during shifts) were provided explaining how to use the AND. In the intervention week, study participants removed syringes manually or automatically with the AND at their convenience. During the first week and third week, outcomes were derived through video footage of syringe processing. Surveys were conducted after the first and third weeks, and 15 participants were interviewed after the third week.
3) Overview of the AND
The AND attaches to an existing sharps container cart or a fixed container. When a syringe is inserted into the AND, it cuts the needle and disposes of it at once (Figure 2). In its original configuration, the AND used infrared light to recognize the syringe, but a button was used in the present study to operate it manually to ensure accuracy. The AND can handle both capped and uncapped syringes.
There are some potential dangers when using the AND. For instance, it can malfunction when misused or if the blade is blunt. The AND can also handle only certain types of syringes. Occasionally, the AND operates without an inserted syringe because of its sensitive sensor. We informed HCPs of these issues to protect them from harming either themselves or patients.
2. Video Analysis
1) Participants and sample size
This study compared outcomes before and after the device was used by the same people in the same setting. From August to September 2019, 111 HCPs in the ED were recruited for this study. HCPs were excluded if they were younger than 19 years or declined to participate. Informed consent was obtained from all participants.
We calculated the sample size based on syringe usage over an intervention period of 1 week, not the number of HCP participants. We assumed that about 6,500 syringes would be used in each the pre-intervention week and the intervention week based on experience by ED nurses. According to the central limit theorem, about 6,500 cases were deemed to be sufficient to compare the average time for needle disposal.
2) Study variables
Efficiency was evaluated by monitoring the daily use of the AND. We monitored how many syringes were disposed of in the AND, the normal operation rate of the AND, and the average syringe processing time using existing methods or the AND. Outcomes were derived through video footage of syringe processing that was obtained by installing a camera in the ED. The participants’ faces did not appear in the videos. The data recorded were instances of the device’s use.
3) Data analysis
Two people viewed each video. They were required to reach a consensus about the start and endpoint of the needle’s disposal to within a millisecond. The start point was the moment the needle was laid on the sharps container or in the AND. The endpoint was the moment the needle landed on the sharps container. We calculated efficiency using descriptive analyses, such as mean ± standard deviation (SD), the Wilcoxon rank-sum test, and counting. Data analyses were conducted using R software, version 3.3.1 (R Foundation, Vienna, Austria).
3. Survey
2) Study variables
Demographics: Variables such as sex, age, occupational group, and work history were investigated.
Safety: We performed a survey to determine the current status of NSIs. The questions covered the number of NSIs, the devices that caused NSIs, and the exact nature of NSIs. We evaluated the incidence of NSIs in the pre-intervention week and the intervention week.
Usability: The System Usability Scale (SUS) was applied to assess the usability of existing methods and the AND for removing needles. The SUS scale was employed in its most widely used format, without modifications (Appendix 1).
3) Data analysis
We obtained data on participants’ demographic characteristics. For questions about NSIs, we analyzed the frequency, tendencies, and keywords of the answers to each question to determine the causes of NSIs and participants’ thoughts on them. We calculated the NSI rate using the number of syringes recorded by video and the number of NSI occurrences described in the surveys. We compared the NSI rates in the pre-intervention and intervention weeks by two independent-population proportions tests. We also compared the mean SUS scores ± SD between existing methods and the AND using the paired t-test.
4. In-Depth Interview
1) Participants and sample size
We interviewed 15 people via convenience sampling. We interviewed more nurses than doctors because nurses are the primary users of syringes.
2) Study variables and data analysis
We asked thematically relevant questions, with a particular focus on the AND. We recorded all interviews with permission and transcribed them for analysis. Next, we analyzed the frequency, tendency, and keywords of the answers to each question and categorized them as related to the efficiency, safety, and usability of the AND.
III. Results
1. Demographics
A total of 111 HCPs at risk for NSIs participated in this study. There were more women than men. Most were in their 20s to 30s (96.4%). Over half of the HCPs (50.5%) had been working for under 3 years. Their characteristics are presented in Table 1.
2. Video Analysis: Efficiency
1) Utilization rate
The AND usage for each day of the intervention week was consistent. Two types of needles can be processed by the AND: general syringes and Luer-Locks (Merck, Burlington, MA, USA). In the intervention week, a total of 3,720 general syringes and Luer-Locks were used, of which 2,114 (56.8%) were processed with the AND.
2) Processing time and normal operating rate
The average times for syringe disposal were compared, assuming a normal disposal time of <10 seconds. The average processing time using the existing manual method was 2.32 ± 1.14 seconds and 1.77 ± 3.71 seconds for the AND. The median processing time using the existing manual method (2 seconds; interquartile range [IQR], 1) and the median processing time using the AND (1 second; IQR, 0) were significantly different (p < 0.001). To calculate the normal operation rate of the AND, device malfunction was defined as an operation time greater than 2 seconds, based on the existing method’s average time of 2.32 seconds. The number of syringes processed manually was 3,958, of which 111 were discarded without removing the needles. Most syringes and needles (97.20%) were separated and discarded as recommended. There were 2,114 syringes processed by the AND, of which 1,916 (90.6%) were normally processed and 198 were not processed due to a malfunction (9.4%). Thus, the normal operation rate of the AND was 90.6%.
3. Survey
1) Safety of existing methods
Eighty-eight nurses and 23 doctors were surveyed to assess instances of NSIs, including the needles that caused NSIs, when NSIs occurred, and HCPs’ work experience at the time of NSIs. These questions dealt with all participants’ work experience with no time limit.
Two hundred and fifty-seven NSIs occurred, most commonly with general syringes (47.5%), butterfly needles (20.6%), and intravenous catheters (20.2%). The needles causing NSIs varied according to the cause of the NSI. NSIs occurred more frequently during disposal than in preparation for treatment or at a patient’s bedside (Figure 3).
2) Safety: NSI occurrence during the study period
During the pre-intervention week, there were seven NSIs, of which two were with general syringes in the disposal process. During the intervention week, three NSIs occurred, one of which was with a general syringe in the disposal process. The NSI rate for using a general syringe that the AND could dispose of was 0.03% in both weeks, which was not significantly different (p = 1.00) (Table 2).
3) Usability (SUS)
The mean SUS score was 65.7 ± 13.1 for the existing disposal method and 62.6 ± 15.8 for the AND. This difference was not statistically significant (p = 0.14) (Table 3).
4. In-Depth Interviews
The interviews focused on the advantages and disadvantages of the AND in terms of efficiency, safety, and usability. The participants’ answers are shown in Table 4.
IV. Discussion
1. Rationale for a Mixed-Methods Study
We designed this study with a convergent mixed-methods model to obtain valid results based on comprehensive and corroborative data. The quantitative study for the AND was intended to elicit a diverse range of maximally objective outcomes through video recordings made at real clinical sites and the use of the SUS, an objective usability scale. A qualitative study was also conducted to evaluate usability and experiences through participants’ opinions. The AND reduced the syringe disposal time compared to the existing method, but failed to replace the existing method completely, and the SUS score for the AND did not differ significantly from the current process, indicating that the AND seemed to be less effective. However, the qualitative results showed positive reviews of the device, which would not have been clear based on the quantitative results alone.
2. Rationale for the ED as Locale
EDs operate 24 hours per day. HCPs in EDs have a greater risk of sharps injuries than other departments and NSIs are more frequent [3,11]. A previous study found that a significant portion of NSIs and sharps injuries (52.0%) occurred with ordinary syringes and during recapping [12–14], and removing a needle from a syringe or placing a needle in a full medical waste container was identified as the most common cause of NSIs [12,15]. Thus, it was meaningful to evaluate the effectiveness of the AND in an actual ED environment.
3. Strengths of Our Study Compared to Previous Studies
When introducing an engineered safety device, it is important to consider the device’s performance, safety, and user satisfaction [16]. Moreover, because of the tradeoff between effectiveness and safety, a comprehensive range of aspects should be analyzed [17]. Previous studies often only investigated NSI reduction as an indicator of safety. However, this study is meaningful in that it analyzed the device’s introduction through a multifaceted approach examining efficiency, safety, and availability, rather than a single outcome.
Healthcare safety issues result from complex interactions between providers, patients, and medical devices. NSIs do not occur only at a particular place or moment. Therefore, NSIs should be considered in the overall process of handling needles. For example, improvements in the disposal process may affect needle use more generally, such as reducing needle recapping, which is not a direct disposal method and is closely related to NSIs. It is difficult to change the existing system using only one simple device. However, we sought to understand NSIs as an overall phenomenon involving how needles are handled within the ED, as well as container-related NSIs at the disposal stage. This study can be used as a basis for further research.
4. Interpretation of the Negative Quantitative Results
1) Lack of significance for the NSI rate: the ED environment
The reason for the lack of a significant improvement in the NSI rate may relate to the nature of an ED. Because an ED is a more complex environment than other hospital environments and is a setting where NSIs frequently occur, the short period of the study and the fact that the AND could only lead to improvements in the disposal phase might explain the lack of a significant impact on the incidence of NSIs in the ED, where many factors are present. In addition, previous studies rarely showed a significant reduction in NSIs before and after introducing safety containers [10,18,19].
2) Lack of significance for the NSI rate and SUS score: limitations of disposed syringe types and the short study period
If the AND had handled a broader range of syringe types and been placed in more locations in the ED, better results may have been found in terms of NSI reduction and the SUS score. Furthermore, we might not have had sufficient time to compare usability and NSI reduction. A longer study may be necessary in light of the time needed for new behavioral changes to be established after the introduction of new devices.
3) Operating time reduction and the normal operating rate
The average time for needle disposal decreased from 2.32 to 1.77 seconds using the AND, with a malfunction rate of 9.4%. This time difference is insufficient and unacceptable. However, this finding demonstrates that efforts would be needed to increase the normal operation rate of the device in the clinical environment, not just in the experimental setting, because several factors related to the device’s operation play a role in the clinical field. When the AND is introduced to actual clinical practice accompanied by efforts to improve the normal operation rate of the device, the workflow might not be disrupted because there is not a substantial time difference from the existing needle removal method.
5. Limitations
First, this study was conducted in only one department at a single hospital. Therefore, it is difficult to generalize the effectiveness of the introduction of this device. We need to expand the study to more hospitals. Second, the skills and familiarity of HCPs with the AND were not evaluated. Previous research on the application of new devices was generally conducted over more than 1 year. Although the AND is considered simple to use, it may not be sufficient to compare only 1 week of use with the much longer periods analyzed in previous research. Third, the study period was insufficient to examine the NSI rate because NSIs are rare. We designed this study to compare outcomes before and after the introduction of the device, considering the number of syringes used. Therefore, we believe that a more extended period of testing will be required to examine the decrease in NSIs. Fourth, we investigated NSIs only using the participants’ recall. Therefore, more accurate methods are necessary to obtain information on the actual occurrence of NSIs.
6. Conclusion
The AND reduced the time for needle disposal, but the normal operation rate was not adequate. The SUS score for the AND was not significantly different from that of the existing method, and introducing the AND did not reduce the NSI rate. In the in-depth interviews, HCPs said the main disadvantages were related to the operational aspects of the device. The advantages were related to benefits when using the AND, such as decreasing direct contact with hazardous waste, not having to recap syringes, and needing less wrist strength. Although there are some restrictions on introducing the AND right away, this study showed its potential usefulness, which could be enhanced by efforts to improve the device’s operability. A longer study period is needed to fully achieve safety, efficiency, and safety.
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