Li-Ying Lee1, Tsung-Yi Lin2, Su-Fen You3,4, Jer-Hao Chang1
1Department of Occupational Therapy, College of Medicine, National Cheng Kung University, Taiwan,
2Department of Mechanical Engineering, Southern Taiwan University of Science and Technology,
3Department of Medical Sociology and Social Work, Kaohsiung Medical University, Taiwan,
4Department of Medical Research, Kaohsiung Medical University Hospital, Taiwan
INTRODUCTION
Healthcare workers are often at high risk of musculoskeletal disorders and often caused by patient lifting and transfer tasks. [1,2,3,4] Previous study also showed high posture risk in manual patient lifting. [5] To decrease injury risk in patient transfer tasks, no-lift policy was promoted in some countries which suggested using mechanical lifting devices can help reduce musculoskeletal injury of healthcare workers. [6,7] However, uncomfortable feelings, space demand, long time consumption, and high cost were prime limitations that decrease the workers’ preference to use lifting devices. [8,9,10] An innovative lifting device with multi-mode approach instead of former suspension type was designed to improve the limitations of device properties. The purpose of this study was to investigate the effectiveness and user preference of the multi-mode lifting device in reducing the operation risks during patient-transfer tasks.
METHODS
Equipment
Participants
This study recruited 34 healthcare workers including therapists, care assistants and nurses as participants. The inclusion criteria were ages from 20 to 59 years old and having patient-transfer experience in workplace. Participants with acute musculoskeletal disorders were excluded.
Procedures
First, participants were asked to perform transfer tasks by manual method and acquired the ergonomic advices from the researcher to improve their manual transfer skills. Then the participants learned to use the multi-mode lifting device and practice with a simulated patient. The participants practiced transfer tasks by both manual method and the multi-mode lifting device several times until they were able to transfer simulated patients safely.
The simulated patients included one male and one female with regular body weight and height in Taiwan. The participants transferred both the male and female simulated patients from bed to chair out of a distance by manual method and multi-mode lifting device in random order. The researcher videotaped the process of each transfer trial for coding to determine posture risk with Ovako Working Posture Analysis System (OWAS) and pull- push risk with Key Indicator Method. Postures observed were classified into four risk ranks. Rank 1: normal postures which do not need any special attention. Rank 2: postures must be considered during the next regular check of working methods. Rank 3: postures need consideration in the near future. Rank 4: postures need immediate consideration. [11, 12] The scores of pull-push risk with Key Indicator Method are categorized into four risk ranges: risk range 1 (score <10), risk range 2 (score 10 to <25), risk range 3 (score 25 to <50), risk range 4 (score≧50), which higher scores are with higher risk. The time consumption in each trial was also recorded by seconds.
After participants finished each trial in different contexts, they scored their perceived exertion with Borg Rating of Perceived Exertion questionnaire [13] and the usability with System Usability Scale (SUS). [14] Borg Rating of Perceived Exertion questionnaire scores from 6 to 20, and higher score indicates higher exertion demand. SUS scores from 0-100, and higher score indicates higher level of acceptability to a product. Scores lower than 50 indicates not acceptable, scores from 50 to 70 indicates marginal, and scores higher than 70 indicates acceptable.
Analysis
To compare the differences of posture risk, pull-push risk, time demand, and perceived exertion between two modes of the multi-mode lifting device and manual transfer method, Wilcoxon signed ranks test, Friedman test, and repeated measure ANOVA were adopted. Usability analysis was presented in descriptive forms.
RESULTS
The average age of participants was 36.4±12.5 years old with range from 21 to 58 years old. Their work experience was averaged as 4.6±6.6 years. Most of the participants were female (79.4%). The majority profession domains in order were therapists (52.9%), care assistants (44.1%), and nurses (3%).
In posture risk, two modes of the multi-mode lifting device and manual method were significantly different for both male and female simulated patient (p<.001) in statistics. The risk rank of manual method showed higher risk than both modes of lifting device in statistics and was mostly in rank 3 and 4 (Table 1). In pull-push risk, all transfer methods were scored from 18.5 to 23.9 as the risk range 2, which suggest no hazard for common workers (Table 2).
The results of preference to use are showed in Table 3. Time consumption in two modes of the multi-mode lifting device and manual method were significantly different in statistics. (p<.001). Both modes of lifting device demanded statistically significantly more time than manual method to finish transfer tasks. In different transfer methods, perceived exertion was significantly different (p<.001) in statistics. Perceived exertion score of both modes of lifting device for female simulated patients were 9.5± 2.1 & 9.7± 2.1 as the level of “very, very light” and for male simulated patients were 10.4± 2.2 & 10.5± 2.2as the level of “light”. Perceived exertion score of manual method for female simulated patient was 12.5± 2.6 as the level of “light” and for male simulated patient was 13.5± 3.1 as the level of “somewhat hard”. Both modes of lifting device were perceived statistically significant less exertion than manual method. The mean score of usability was 72.7± 11.2, showed the device is acceptable for the users. Although Figure 3 showed there were some outliers, 50% of participants scored SUS from 66.9 to 80.6, which fall in the range of “marginal” and “acceptable”.
Simulated patient gender
|
Front- approach Mode Risk Rank
|
Lateral- approach Mode Risk Rank
|
Manual Method Risk Rank
|
|||||||||
I
|
II
|
III
|
IV
|
I
|
II
|
III
|
IV
|
I
|
II
|
III
|
IV
|
|
Male
|
47.1%
|
35.3%
|
17.6
|
0%
|
23.5%
|
58.8%
|
17.6%
|
0%
|
2.9%
|
5.9%
|
76.5%
|
14.7%
|
Female
|
44.1%
|
38.2%
|
17.6%
|
0%
|
20.6%
|
47.1%
|
32.4%
|
0%
|
0%
|
8.8%
|
85.3%
|
5.9%
|
Simulated patient gender
|
Transfer Methods
|
||
|---|---|---|---|
Front- approach Mode
|
Lateral- approach Mode
|
Manual Method
|
|
Male (means±SD)
|
23.9± 5.9
|
22.4± 4.6
|
20.3± 4.4
|
Female (means±SD)
|
23.0± 5.3
|
22.4± 4.6
|
18.5± 3.2
|
Simulated patient gender
|
Time Consumption (seconds)
|
||
|---|---|---|---|
Front-approach Mode
|
Lateral- approach Mode
|
Manual Method
|
|
Male (means±SD)
|
272.1± 32.4
|
257.6± 45.3
|
117.9± 27.7
|
Female (means±SD)
|
264.7± 36.3
|
252.1± 37.6
|
105.8± 20.6
|
Simulated patient gender
|
Perceived Exertion
|
||
Front-approach Mode
|
Lateral- approach Mode
|
Manual Method
|
|
Male (means±SD)
|
10.4± 2.2
|
10.5± 2.2
|
13.5± 3.1
|
Female (means±SD)
|
9.7± 2.1
|
9.5± 2.1
|
12.5± 2.6
|
DISCUSSION
In operation risk, transfer by the multi-mode lifting device had better performance in both posture risk and pull-push risk with clear data in this study. Comparing with manual method, both modes of the multi-mode lifting device had less posture risk level, which support other previous studies. [15,16] The pull-push risks in all transfer methods here were in the risk range 2 which indicated such moderate load situation was no hazard for normally resilient persons. [12]
In aspects of preference to use, the time consumption when using device was more than manual method, which also agree with previous research. [8,9,17] The longer time demand for transfer task would decrease healthcare worker’s willingness in using lifting device. However, the results of perceived exertion reported with evidences that both modes of the multi-mode
lifting device demanded less exertion than manual method as other previous studies. [9,15,18] Finally, the usability of the multi-mode lifting device were acceptable for most participants.
CONCLUSIONS
The multi-mode lifting device can decrease posture risk of healthcare workers during patient transfer tasks with no hazardous pull-push risk. Longer time consumption would decrease preference of transfer methods, but less perceived exertion and acceptable usability performance of the multi-mode lifting device showed potential of practical application. Healthcare workers will prevent from occupational injuries by exposing less operation risks with this innovative lifting device in patient transfer tasks.
REFERENCES
[1] Hou, J.-Y., & Shiao, J. S.-C. (2006). Risk Factors for Musculoskeletal Discomfort in Nurses. Journal of Nursing Research, 14(3), 228-236.
[2] Cheng, Y.-S., Mao, H.-F., Lee, M.-D., Chen, Y.-C., Wang, T.-C. (2014). Occupational Safety and Health Issues: Nurse Professional’s Patient Handling Methods. The Journal of Long-Term Care, 18 (1), 13-27. DOI:10.6317/LTC.18.13
[3] Lee, H.-C., Lin, P.-C., Chou, M.-C., Huang, Y.-C., Li, Y.-H., Lin, H.-M., Hung, J.-W., Chang, K.-C. Prevalence and Risk Factors for Musculoskeletal Discomfort among Nursing Attendants: A Comparative Review. Formosan Journal of Physical Therapy, 36(2), 55-66.
[4] Kim, H., Dropkin, J., Spaeth, K., Smith, F., & Moline, J. (2012). Patient handling and musculoskeletal disorders among hospital workers: Analysis of 7 years of institutional workers' compensation claims data. American journal of industrial medicine, 55(8), 683-690.
[5] Chang, J.-H., Lee, L.-Y., Hsu, H.-Y., Lin, T.-Y., You, S.-F., Chao, P.-C. Occupation Injury Risk in Transfer Tasks for Health Care Workers by Ovako Working Analysis System (OWAS), 2018 IEEE International Conference on Applied System Invention (ICASI).
[6] Health and Safety Executive. (2016). Guidance on Manual Handling Operations Regulations. Retrieved from http://www.hse.gov.uk/pUbns/priced/l23.pdf
[7] Australian Nursing and Midwifery Federation Victorian Branch. (2015). Safe Patient Handling. Retrieved from https://www.anmfsa.org.au/wp-content/uploads/2018/09/safe-patient-handling-.pdf
[8] Collins, J. W., Wolf, L., Bell, J., & Evanoff, B. (2004). An evaluation of a "best practices" musculoskeletal injury prevention program in nursing homes. Injury Prevention, 10(4), 206-211. doi:10.1136/ip.2004.005595
[9] Engst, C., Chhokar, R., Miller, A., Tate, R. B., & Yassi, A. (2005). Effectiveness of overhead lifting devices in reducing the risk of injury to care staff in extended care facilities. Ergonomics, 48(2), 187-199. doi:10.1080/00140130412331290826
[10] Garg, A., Owen, B. D., & Carlson, B. (1992). An ergonomic evaluation of nursing assistants' job in a nursing home. Ergonomics, 35(9), 979-995. doi:10.1080/00140139208967377
[11] Karhu, O., Kansi, P., & Kuorinka, I. (1977). Correcting working postures in industry: a practical method for analysis. Applied Ergonomics, 8(4), 199-201.
[12] Steinberg, U. (2012). New tools in Germany: development and appliance of the first two KIM ("lifting, holding and carrying" and "pulling and pushing") and practical use of these methods. Work, 41 3990-3996. doi:10.3233/WOR2012-0698-3990
[13] Borg, G. (1998). Borg's Perceived Exertion And Pain Scales. United States of America: Human Kinetics.
[14] Bangor, A., Kortum, P., & Miller, J. (2009). Determining what individual SUS scores mean: Adding an adjective rating scale. Journal of usability studies, 4(3), 114-123.
[15] Silvia, C. E., Bloswick, D. S., Lillquist, D., Wallace, D., & Perkins, M. S. (2002). An ergonomic comparison between mechanical and manual patient transfer techniques. Work, 19(1), 19-34.
[16] Koppelaar, E., Knibbe, H. J., Miedema, H. S., & Burdorf, A. (2012). The influence of ergonomic devices on mechanical load during patient handling activities in nursing homes. Annals of occupational hygiene, 56(6), 708-718.
[17] Daynard, D., Yassi, A., Cooper, J. E., Tate, R., Norman, R., & Wells, R. (2001). Biomechanical analysis of peak and cumulative spinal loads during simulated patient-handling activities: a substudy of a randomized controlled trial to prevent lift and transfer injury of health care workers. Applied ergonomics, 32(3), 199-214.
[18] Weinel, D. (2008). Successful Implementation of Ceiling-Mounted Lift Systems. Rehabilitation Nursing, 33(2), 63-87.