A Preliminary Clinical Usability Study to Assess Design, Comfort, Wearability, and Acceptance of Recovery Force's Deep Vein Thrombosis (DVT) Cuff
Phase: NA
Conditions: Deep Vein Thrombosis, Venous Thrombosis
Sponsor: University of Southern California

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COVER PAGE 
 
 
OFFICIAL TITLE OF THE STUDY: A preliminary clinical usability study to assess design, 
comfort, wearability, and acceptance of Recovery Force’s Deep vein thrombosis (DVT) 
cuff. 
 
 
NCT NUMBER: NCT03328624 
 
DATE OF DOCUMENT: OCTOBER 11, 2017 
 

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A preliminary clinical usability study to assess design, comfort, wearability, and 
acceptance of Recovery Force’s Deep vein thrombosis (DVT) cuff. 
 
 
Hypothesis 
 
The primary hypothesis for this Phase I study is following Recovery Force’s DVT II cuff 
demonstration, participants will be strongly satisfied with design, comfort and wearability of the 
product. This will lead to a Phase II study, where it can be predicted that their perceived 
adherence to wearing the device will be high. 
 
Outcome Measures 
 
Primary Outcome Measures are Wearability/Comfort and patient acceptance, which are the two 
key components for adherence and compliance to the product. This is evaluated through the 
Cuff Evaluation Questionnaire: For Assessment of cuff comfort, flexibility, temperature, ability of 
the cuff to remain in place on the leg, and sweatiness of the leg. 
 
Secondary Outcome Measures are Usability and Design-Human Factors. This is designed to 
confirm that product and engineering requirements are in alignment. These outcome measures 
will provide feedback on compression, cycle sequence, target zones, materials, comfort, and 
mobility.  
 
 
Methods and Study Design 
  
A single site, observational study will be conducted at the University of Southern California 
(USC) with participants who have and/or have had previous experience with DVT pneumatic 
cuffs. Study staff will examine participants overall experience, product functionality and 
perceived adherence to Recovery Force’s DVT II cuff. About 46 participants will be recruited 
into the study. (Estimated recruitment duration – about 2 months) 
 
Study Population and Inclusion Criteria 
 
Male or Female Age 18-65 who  have had exposure with a DVT cuff on the calf within the last 6 
months from a previous or current clinical condition will be enrolled to the study.  
 
Recruitment 
 
Participants will be recruited from USC database, and referrals from physicians, clinicians, and 
vascular clinicians and staff. Study staff will obtain approval from the IRB and consent from 
each participant. All subjects will be consented individually in a private room. All study 
documents, including original signed consents, will be maintained for up to 10 years. Personal 
information regarding participation in this study may be disclosed if required by state law.  
 
Tests and Procedures 
 
Pre- Demonstrations Questionnaires: Prior to beginning the prototype demonstration, 
participants and study staff will have completed an inclusion questionnaire with demographic 

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information and a Prior DVT Cuff Experience questionnaire. Demographics information includes 
Age, Gender, Ethnicity, Brief Medical History, Last Month of DVT Cuff use, Type of Prior DVT 
Cuff/Model.  
 
Prior Experience with DVT Devices Questionnaire: A series of questions used to gauge 
patient experience with and attitudes towards DVT devices. Major topics will include the 
application and availability of DVT devices, perceptions regarding bothersome and pleasurable 
aspects of DVT devices. 
 
Prototype Demonstration: Recovery Force will provide five DVT II prototypes for the study. 
Participants will test DVT II cuff prototype. Each participant will examine, wear, and remove a 
DVT Cuff for a total of 40 minutes test time and turn on the device for a minimum of 20 minutes. 
As participants try on the DVT II, they will be asked to mimic normal behavior 
(walking/sitting/standing/supine position). 
 
Post- Demonstrations Questionnaires: The study will include primary and secondary 
outcome questionnaires that access human factor engineering and usability.  
 
Closing interview: A closing interview of 20 min will be conducted by the study team. A series 
of follow-up post-demonstration questions using a semi-structured interview with an 
interpretative phenomenological analysis approach 34 will be recorded and transcribed by a 
study staff. This interview will focus on initial exposure to the device, user impressions, 
suggestions, critiques and overall appeal.  
 
Sample size calculation 
 
Using a sample power analysis (IBM SPSS), the PI determined 34 total patients will be needed, 
using an error margin of 0.2 points based on overall expected responses to questionnaires, 
assuming 10% missing data, alpha level of 95% certainty. Assuming a 25% dropout rate, the 
recruitment goal will increase to 46 participants.  
The small sample size was also recommended as a preliminary assessment of product design 
and human factor usability that will provide adequate insight into clinical protocol design for 
future larger statistically powered clinical trials in Phase II to address patient compliance. 
 
Overall patient acceptance will be determined by the patient’s response to the final question on 
the End of Study Cuff Evaluation Questionnaire: “Which Cuff did you like better OVERALL?” If 
at least 75% of patients respond as preferring the new cuff over the traditional, then the study’s 
primary outcome will be achieved 29. 
 
Potential Risks 
 
Risks will be explained to all participants in advance of study enrollment. The main risk is slight 
discomfort from improper use of shoe by over/under tightening the closures.  A user manual will 
be provided to each participant. A second risk is the amount of pressure applied to the bottom of 
the foot may cause slight discomfort. Participants may opt not to participate in the study at any 
time; additional participants will be recruited through the pool of eligible participants. 
 
Potential Benefits of the Proposed Research to Human Subjects and Others 
 

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There is no known individual benefit for participating in this study. With the information provided 
by the study, participants may benefit from understanding the need for patient compliance to 
receiving maximum therapeutic benefit by improving lower limb tissue reperfusion, pressure 
distribution, mobility (quality of life).  
 
Importance of the Knowledge to be Gained 
 
It is anticipated that this study will have potential benefits to society, as it will provide new 
insights and ultimately education to patients at risk for DVT, which may translate to actionable 
health outcomes. As the risks to the subject are minimal, the relation of risk to the importance of 
the knowledge expected is reasonable for this study. This research may provide a more 
effective compression therapy for patients at risk for DVT.