Determine the Most Effective Intervention for Hemorrhage Control Readiness for Laypersons
Phase: NA
Conditions: Traumatic Hemorrhage
Sponsor: Brigham and Women's Hospital

A Randomized Controlled Trial With Retention Testing to Determine the Most Effective Intervention for 
Hemorrhage Control Readiness for Laypersons: The PATTS Trial 
 
January 29, 2018 
 
Study Protocol and Statistical Analysis 
 
 

a. Study design:  
a. Prospective, randomized, multi-arm, open-label trial with follow-up retention 
testing 
 
b. Location: 
a. Gillette Stadium, Foxborough, Massachusetts, USA. 
 
c. Consent:  
a. Participation in the study was voluntary and oral consent was obtained from all 
subjects. A fact sheet was provided to all participants.  
 
d. Inclusion/Exclusion criteria:  
a. Adult (18 years and above) volunteers with no prior hemorrhage control training 
or experience were included in the trial. 
b. Anyone with previous formal hemorrhage control or tourniquet training was 
excluded from the trial analysis.  
 
e. Randomization: 
1. Eligible study subjects were randomized into the following arms using block 
randomization such that for every four participants, one was randomized to each of the 
four arms:  
i. Control arm: Study subjects in this arm of trial received no intervention (no 
training or access to point-of-care prompts) to assess baseline competence in 
hemorrhage control. 
ii. Experimental arm 1: Study subjects in this arm were given the American College 
of Surgeons Bleeding Control Basic (B-Con) in-person training course by 
qualified instructors. This curriculum was developed by a collaboration between 
American College of Surgeons and the Hartford Consensus.9 The session included 
a multimedia presentation in a class format that included some background 
information about extremity hemorrhage and potential benefits of immediate first-
response and hemorrhage control, steps to take in a mass casualty scenario and 
instructional videos on hemorrhage control modalities and their appropriate use. 
This was followed by hands on training in hemorrhage control, with 1:4, 
instructor to trainee ratio.  
iii. Experimental arm 2: Study subjects in this arm received a commercially 
available audio bleeding control kit. The kit included diagram and visual aids to 
identify the correct severity of injury and determine the appropriate method of 
bleeding control. The kit also had buttons on it to play stepwise audio instructions 
on application of compression dressing, hemostatic packing and tourniquet 
application in two languages (English and Spanish). The audio kits were bought at 
market price and the name of the manufacturer was not mentioned in the 
manuscript to avoid conflict of interest. 
iv. Experimental arm 3: Study participants in this arm of the trial received bleeding 
control flashcards that contain diagrams and figures to correctly identify the 
severity of injury and visual instructions on appropriate application of pressure 
dressing, hemostatic packing and tourniquet. 

 
f. Sample size calculation:  
a. Sample Size calculation was done using Stata v14.1 with 80% power and an alpha 
level of 0.05. Trial arm paired-comparisons were taken as independent trials and 
sample size was calculated for each pair. The largest number was taken as the 
sample size for each arm. The smallest difference in application rate, and the arm 
used to determine sample size calculation, was between the control and flashcard 
arm.  
i. Control group expected application rate 20% based on prior studies 
ii. Flashcard Proportion expected application rate 44% based on prior studies 
b. Final sample size is 412 with 103 subjects in each arm. This is before exclusion of 
individuals with prior hemorrhage control training thus, to account for 20% of 
individuals to report prior training, over 125 individuals will be recruited to each 
arm. 
g. Pre-study questionnaire:  
a. Study subjects were given a pre-trial questionnaire to gather information 
regarding age, gender, level of education, any prior first-aid training, and if they 
reported prior first-aid training, whether it included hemorrhage control training.  
Those individuals who reported prior hemorrhage control training were then 
asked an open ended question about what that training consisted of. The 
questionnaire also included questions to determine participants willingness to 
assist in an emergency and self-reported comfort level in acting as a first-
responder in a mass causality scenario. Answers were presented on a Likert-type 
scale. 
h. Post-trial questionnaire:  
a. After the hemorrhage control test, all participants were given a post-trial 
questionnaire which assessed their perception of usefulness of the training, 
willingness and self-reported comfort-level in providing first response in a mass 
causality scenario on a Likert-type scale. 
b. Questionnaires will also be re-administered at 3-9 month retention testing, which 
will assess participant perception of usefulness of the training, self-reported 
willingness and comfort-level in providing first response in a mass causality 
scenario on a Likert-type scale as well as other questions relating to emergency 
preparedness and hemorrhage control. 
 
i. Protocol:  
a. A reviewer will read aloud a simulated scenario describing an explosion in a 
public gathering. A bleeding mannequin with traumatic amputation of leg just 
above the knee will be present. The participant will then be directed to a nearby 
bleed-control box and asked to stop the bleeding. The bleed-control box will 
contain a combat application tourniquet (CAT). The reviewer will start timing 
after directing the subject to the bleed-control box. 
Subjects in the control arm were directly subjected to the bleeding control 
test. Experimental arm 1 subjects will attend B-Con course taught by ACS trained 
instructors and then subjected to the test. Experimental arm 3 and 4 subjects 
received an audio guide and flash card in their bleed-control box respectively, 

during the test. At retention testing, participants were not retrained nor had 
available point of care prompts.  
The participants were timed until they feel that they had stopped the 
bleeding. Time for complete bleeding control and tourniquet application was 
recorded only for subject who appropriately control the hemorrhage within 7 
minutes. Appropriateness of hemorrhage control was determined by correct 
placements of tourniquet and adequate pressure of the tourniquet as determined 
by attempting to forcefully slide a Kelly clamp under between the tourniquet and 
the extremity of the mannequin. For unsuccessful hemorrhage control, the reason 
for failure was recorded. No feedback was given to the participant during the test. 
b. 20 reviewers were used for the purpose of this study. All the reviewers were 
physicians, nurses, and EMTs, trained in hemorrhage-control. 
1. After testing of the two point of care prompt arms and the control arm, these individuals 
then underwent the ACS B-Con training from qualified instructors. This training was 45 
to 60 minutes long, consisting of an audio-visual presentation with tourniquet application 
instructions followed by hand-on training under the supervision of an instructor, the same 
as the B-Con intervention arm. 
2. Test for retention:  
a. 3-9 months after the trial, we planned to test all study subjects with a simulated 
mass causality scenario for retention of knowledge and skills. This test will be the 
same as the initial test for competence at tourniquet placement in the trial and the 
same evaluation form will be used to evaluate the study subjects. 
 
j. Donation of study material:  
a. At the end of the retention study, the bleeding control boxes will be donated to the 
stadium, to be co-located with AEDs.  
 
1) Statistical analysis:  
a) The primary outcome in our study was the correct application of tourniquets.  The main 
analyses in the randomized study were the pairwise comparisons of the proportion of 
correct tourniquet application in each of the three intervention arms to the control arm.  
b) In the initial testing phase, the proportion of participants who correctly applied a 
tourniquet in the three intervention arms were compared to control using three pairwise 
two-sided Fisher's Exact Test of the three interventions to control in an intent-to-treat 
analysis (as randomized). 
c) To analyze retention, we performed two pairwise comparisons: 1) all participants tested 
at retention versus initial control to identify long-term efficacy (correct tourniquet 
application) compared to no training; 2) participants tested at retention versus initial 
testing in B-Con randomized arm to identify if there is a significant skill decay 3-9 month 
after training. Generalized estimating equations z-tests were used in these pairwise tests 
to account for the repeated measures on participants who were in both the initial and 
retention phases. 
d) At retention testing, an a priori planned logistic regression analysis was performed to 
identify any demographic associations with correct tourniquet application between 3 and 
9 months after B-Con training. It also assessed for different effects due to the original 
(randomized) arm in initial testing in case the combination of randomized arm and then 

B-con training had differential effects on correct tourniquet application (although our a 
priori hypothesis was that there would be no difference). Age was divided into 
categorical variables creating three groups using previously defined age breaks: young 
adult [18-35 years old (yo)], middle aged adult (35-55 yo), and older adult (> 55 yo). This 
model assessed for an association between days since training to retention testing, 
allowing for a non-linear effect. We assessed for co-linearity, and interactions between 
variables [age and education, age and sex, age and prior training, sex and education, sex 
and prior training] and ran diagnostics on the model fit. We used Hosmer and 
Lemeshow’s goodness-of-fit test to evaluate our model.  
e) The Wilcoxon rank sum test was used to compare time to correct tourniquet application 
across arms (restricted to participants in each arm who correctly applied the tourniquet). 
Demographic variables for each intervention arm versus control and retention versus 
control were compared using Wilcoxon rank sum tests for continuous variables and two-
sided Fisher Exact tests for categorical variables.  
f) The data on empowerment will be analyzed using descriptive statistics. Likert type data 
will be analyzed using non-parametric tests (Wilcoxon sign rank, Kruskal-wallis test).  
Single group repeated measures analysis will be used to analyze the change in 
empowerment over time. The Likert type data will also further be analyzed by 
transforming it into dichotomous categorical data with those reporting being very likely 
or very comfortable being a positive response and anything less than that being recorded 
as a negative. The various empowerment parameters will be assessed for their 
relationship with skill efficacy (correct tourniquet application).