The Step Home Trial: Utilising Physical Activity Data in the Acute Post-operative Setting
Conditions: Surgery, Enhanced Recovery, Technology
Sponsor: Imperial College London

 
Protocol V1.7 
1 
 
The Step Home Trial: Utilising Physical Activity data in the Acute Post-
operative setting 
 
Aliza Abeles, Richard Kwasnicki, Ara Darzi 
 
Department of Surgery and Cancer, St Mary’s Hospital, Imperial College London 
Version 1.7, Date 12/05/2016 
 
Contact 
Ms Aliza Abeles 
Department of Surgery and Cancer 
10th Floor QEQM building  
St Mary's Hospital 
Praed Street  
London W2 1NY United Kingdom 
 
Email: a.abeles@imperial.ac.uk 
 
Sponsor: Imperial College London 
 
Insurance and Indemnity: Imperial College London 
 
Aims 
1. To assess how post-operative inpatient physical activity levels correlate with patient 
recovery and duration of stay following elective surgical operations. 
2. To investigate the utility of physical activity data to the post-operative surgical team as 
part of standard patient observations 
 
Background 
The importance of patients ambulating following their surgery has long been recognised as an 
important factor for post-operative recovery. From the reduction of chest infection and venous 
thromboembolism, to promoting the maintenance of muscle mass, activity following surgery 
is an essential component of the enhanced recovery after surgery (ERAS) paradigm.(1) In our 
pre-trial questionnaire from a multidisciplinary cohort of clinicians at an enhanced recovery 
workshop 85% of respondents thought that physical activity post operatively was highly 
important (LCA ERAS event – unpublished data). 
 
Furthermore, physical activity is also used as a marker for assessing recovery after an 
operation. When a surgical team reviews patients on the post-operative ward round they 
frequently seek the patient’s physical activity status, which is then used in conjunction with 

 
Protocol V1.7 
2 
 
other observations (e.g. heart rate, blood pressure, temperature) and patient examination to 
assess a patient’s progress and plan for their discharge home.  
Hospitals use technology in a variety of ways to monitor patients, these include more invasive 
methods (e.g. oesophageal Doppler monitoring for cardiac output) as well as less invasive 
methods of observations (e.g. pulse oximeter for heart rate and oxygen saturation 
measurements, electronic blood pressure monitors). Currently, however, there is no valid 
objective measure for physical activity, and responses with regard to how a patient’s activity 
is progressing is subjective and can be variable.  
 
Recent advances in technology have led to the emergence of wearable devices that are small 
and minimally invasive with the ability to monitor not only the basic baseline observations 
(heart rate, temperature etc.) but also to monitor physical activity levels.(2) The integration of 
Bluetooth and other wireless technologies have improved communication and interfacing with 
smart devices such as mobile phones and tablet computers. Such technologies provide a very 
realistic platform to facilitate the collection and collation of large amounts of data which can 
be processed and presented to the surgical team to allow objective analysis of patients post-
operatively and aid decision-making. 
 
Some groups have begun to investigate activity levels using wearable sensors, for example 
monitoring of physical activity in patients undergoing ambulatory pH monitoring, (3) and the 
development of an objective mobility assessment tool using a wearable motion sensor after 
lower limb reconstruction.(4) However, there has been minimal objective information gained 
with regard to inpatient activity and how this correlates both with the duration of hospital stay 
and longer term outcomes. 
 
One study, (5) looking at day case laparoscopic cholecystectomy patients used accelerometery 
data to monitor physical activity levels one week before and one week following surgery. They 
found that the majority of patients did not return to their baseline activity level until at least 
one week following surgery. A further study, (6) looking at cardiac surgery in-patients showed 
a correlation between the number of steps a patient took each day following surgery and their 
length of hospital stay. 
 
This study will provide further evidence for the usability and utility of wearable sensors in the 
inpatient surgical setting. It will provide supporting evidence for surgeons to confidently 

 
Protocol V1.7 
3 
 
analyse and assess patients in hospital, allowing for safe and expedient discharge home as well 
as identify high-risk patients who are likely to require extra support and surveillance in the 
community setting.  
 
Hypotheses 
1. Inpatient physical activity is a predictor of length of stay 
2. Physical activity data has important utility as an objective measurement for surgical 
teams 
 
Methods 
Trial Design 
A single-centre observational study will be conducted at Imperial College NHS healthcare 
Trust (UK). The work will be split into two phases. 
 
Phase One 
50 patients due for elective surgical procedures will be recruited from St Mary's Hospital 
outpatient general surgical clinics. Potential participants will be given a participant information 
sheet and then time to consider whether they wish to participate. If patients wish to participate 
they will have the opportunity to ask questions before signing a consent form.  
 
At the pre-operative assessment (1-2 weeks prior to operation) participants will be given a 
wrist-worn motion sensor (AX3 accelerometer, Axivity, Newcastle upon Tyne, UK) together 
with an information sheet to explain how and when they must wear it. The participants will 
also be given a generic self-reported Health Related Quality of Life questionnaire (SF-36) to 
complete.  
 

 
Protocol V1.7 
4 
 
Figure 1. Axivity AX3 logging accelerometer 
 
The AX3 is an ADXL345 tri-axial accelerometer manufactured by Analog Devices, weighing 
11g and contains a non-volatile flash memory chip linked by a USB enabled microcontroller. 
A temperature sensor, ambient light sensor, real time clock (RTC) and lithium polymer 
battery are also integrated into the sealed polycarbonate puck. The product is compliant with 
the Directive 2004/108/ EC; (CE marked). The product has been tested to BS EN 61000-6-
1:2007 and BS EN 61000-6-3:2007. 
 
Figure 2. Axivity AX3 accelerometer worn on the wrist. 
 
Participants will be asked to wear the wrist-worn sensor at all times (it is showerproof) except 
if they are swimming or taking a bath, and will be advised to go about their normal daily 
activity. The patient will continue to wear the sensor on admission and throughout their hospital 
stay, it will be collected back just prior to discharge.  
 
At follow-up clinic, 2-3 weeks post-operatively, patients will be asked to complete a further 
generic self-reported Health Related Quality of Life questionnaire (SF-36). A further Health 
related Quality of Life questionnaire will be completed at 3-6 months at the next follow-up 
outpatient clinic. 
 
Staff (theatre, recovery and ward) will be briefed before patient recruitment is started and there 
will be a feedback period for both staff and patients early in the data collection period to ensure 
that there are no issues with patient safety or any other concerns that need to be addressed. The 
first 5 patients will be asked to complete a feedback form at their follow-up patient clinic in 
order to identify any issues or concerns early on in the data collection period. 

 
Protocol V1.7 
5 
 
 
The SF-36(7), which has been validated as a measure of post-operative recovery, (8) assesses 
eight health concepts including physical activity, mental health and general health perceptions. 
The questionnaire yields scores (0-100) for each concept which are then combined to produce 
a physical component score and a mental component score.  
 
Inclusion 
Exclusion 
Undergoing elective surgical operative 
procedure 
Unable to mobilise independently 
Have medical condition characterized by 
movement disorder e.g. Parkinson’s Disease 
Unable to understand and complete the SF-
36 (unless interpreter present) or lack 
capacity to consent 
Psychological Disorder 
Aged less than 18  
 
 
Consenting 
The principal researcher will take consent (following an initial verbal consent by the surgeon 
indicating the patient’s agreement to be contacted by the researcher as well as for their records 
to be viewed by the researcher). The patient will have time in the clinic to read the information 
sheet, ask any questions and decide if they wish to participate. If the patient is happy then 
written consent will be taken (including consenting to fully understanding the participant 
information sheet).  
 
Participant schedule
 
 
Outcome measures 
Patient identified 
in outpatient clinic
Information 
leaflet given, 
time for 
questions
Consent taken
Wrist-worn 
sensor given to 
patient (to be 
worn 
continuously)
Sensor collected 
on discharge from 
hospital
SF-36 
completed
SF-36 repeated at 
follow-up clinic 
post-operatively 
2-3 week and 3-6 
months
Short Feedback 
questionnaire for 
the first  and last 5 
participants of 
study

 
Protocol V1.7 
6 
 
Primary outcomes 
 Pre and post-operative (inpatient) physical activity levels 
 Length of stay 
Secondary: 
 Self-reported quality of life: SF-36 score, broken down into physical and mental 
component scores 
 30 day readmission 
 Complications: Wound infection, chest infection, abdominal/pelvic collection, deep 
vein 
thrombosis/pulmonary 
embolism, 
myocardial 
infarction, 
need 
for 
reoperation/further procedure 
 
Patient demographics will be collected via medical records. This includes medical history 
(including surgical history, comorbidities) and biometrics such as age, gender, weight, height.  
 
Data Analysis 
The sensor data will be analysed using software compatible with the specific accelerometer 
sensor. The processing that is carried out provides more easily understandable and manageable 
values for both statistical analysis and graphical representation of results.  
SPSS (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY) will 
be used to analyse the data.  
Data we will collect includes 
 
Overall physical activity level 
 
Frequency and duration of bursts of physical activity 
 
Intensity levels of activity each hour and day 
 
Patient activity behaviour – times of day activity occurs 
Data we will analyse 
 
Correlation between pre-operative +/- post-operative activity levels and length of stay – 
Spearman Rank Correlation 
 
Correlation between the difference between pre-op and post-op activity levels and length of 
stay - Spearman Rank Correlation 
 
Correlation between physical activity levels and the SF-36 score, 30 day readmission rates and 
complications - Spearman Rank Correlation 

 
Protocol V1.7 
7 
 
 
Phase Two 
An extra 5-10 patients will be recruited and the exact same participant schedule will be 
followed. However, once the patient has been discharged from hospital the activity level data 
of these patients will be presented to the clinical team. We will then ask the members of the 
team to fill in a questionnaire/feedback survey with regard to the results presented in order to 
find out the utility of the data and what clinical teams think about the usability of the data. 
The patients themselves will also be told their activity level data in the follow-up clinic and 
will also asked to fill in a questionnaire/feedback survey to help us understand how patients 
view this data and its uses. 
 
Ethical Approval 
The Chief Investigator has obtained approval from the NRES Committee London – City Road 
& Hampstead Research Ethics Committee.  The study has also been submitted for Site Specific 
Assessment (SSA) at Imperial College NHS Healthcare Trust.  The study will be conducted in 
accordance with the recommendations for physicians involved in research on human subjects 
adopted by the 18th World Medical Assembly, Helsinki 1964 and later revisions. 
 
 
Confidentiality 
The Chief Investigator will preserve the confidentiality of participants taking part in the study 
and is registered under the Data Protection Act. 
 
Indemnity 
Imperial College London holds negligent harm and non-negligent harm insurance policies 
which apply to this study. 
 
Sponsor 
Imperial College London will act as the main Sponsor for this study.  Delegated responsibilities 
will be assigned to the NHS trusts taking part in this study.   
 
Funding 
Imperial College London are funding this study.  
 

 
Protocol V1.7 
8 
 
Audits 
The study may be subject to inspection and audit by Imperial College London under their remit 
as sponsor and other regulatory bodies to ensure adherence to GCP and the NHS Research 
Governance Framework for Health and Social Care (2nd edition).  
 
Publication Policy 
We intend to publish the results of this study in high quality peer-reviewed international 
journals and at a similar standard conferences. In addition if the results could lead to 
improvement in clinical practice we would look to cite the publication or provide a separate 
summary for relevant clinical bodies, including advisers of local protocol. 
 
Organisation  
We will be recruiting only cases from one specific consultant to remove any bias, we should 
therefore be able to recruit 2-3 patients per week and would conduct the study over 5-6 months 
in order to recruit 55-60 patients.  
 
Clinical Impact of Research 
This study will provide objective evidence of a link between physical activity and length of 
hospital stay. This will act as a clear rationale for developing a system to provide activity 
observations for doctors. Giving hospital staff access to patient activity data has potential utility 
for surgeons, physicians and other allied healthcare professionals. As technology progresses 
further, collection of all patient ‘observations’ is likely to become possible using wearable 
devices.  
 
Summary 
This project will provide supporting evidence for surgeons to confidently, and safely, expedite 
patient discharge from hospital. This boasts advantages financially, freeing up bed space, and 
also to the patients themselves, both physically and psychologically. Furthermore, it may help 
to identify those at high-risk who require extra support in the community setting. 
 
Appendices 
A. Phase One  

 
Protocol V1.7 
9 
 
a. Participant Information sheet V2.2 
b. Patient Consent form V1.2 
c. Patient Feedback form V1.1  
d. Clinician Information sheet V1.2 
e. Clinician Consent form V1.2 
f. Clinician Feedback form V 1.1 
B. Phase Two   
a. Participant Information sheet V1.2 
b. Patient Consent form V1.2 
c. Patient Feedback form V1.1 
d. Clinician Information sheet V1.2 
e. Clinician Consent form V1.2 
f. Clinician Feedback form V1.1 
C. SF-36 Questionnaire 
 
Selected References 
1. 
Gustafsson UO, Scott MJ, Schwenk W, Demartines N, Roulin D, Francis N, et al. 
Guidelines for perioperative care in elective colonic surgery: Enhanced Recovery After 
Surgery (ERAS(R)) Society recommendations. Clinical nutrition. 2012;31(6):783-800. 
2. 
Appelboom G, Yang AH, Christophe BR, Bruce EM, Slomian J, Bruyere O, et al. The 
promise of wearable activity sensors to define patient recovery. Journal of clinical neuroscience 
: official journal of the Neurosurgical Society of Australasia. 2014;21(7):1089-93. 
3. 
Kwasnicki RM, Ley Greaves R, Ali R, Gummett PA, Yang GZ, Darzi A, et al. 
Implementation of objective activity monitoring to supplement the interpretation of ambulatory 
esophageal PH investigations. Diseases of the esophagus : official journal of the International 
Society for Diseases of the Esophagus / ISDE. 2015. 
4. 
Kwasnicki RM, Hettiaratchy S, Jarchi D, Nightingale C, Wordsworth M, Simmons J, 
et al. Assessing Functional Mobility After Lower Limb Reconstruction: A Psychometric 
Evaluation of a Sensor-Based Mobility Score. Ann Surg. 2014. 
5. 
Wasowicz-Kemps DK, Slootmaker SM, Kemps HM, Borel-Rinkes IH, Biesma DH, 
van Ramshorst B. Resumption of daily physical activity after day-case laparoscopic 
cholecystectomy. Surg Endosc. 2009;23(9):2034-40. 

 
Protocol V1.7 
10 
 
6. 
Cook DJ, Thompson JE, Prinsen SK, Dearani JA, Deschamps C. Functional recovery 
in the elderly after major surgery: assessment of mobility recovery using wireless technology. 
Ann Thorac Surg. 2013;96(3):1057-61. 
7. 
Ware JE, Jr., Sherbourne CD. The MOS 36-item short-form health survey (SF-36). I. 
Conceptual framework and item selection. Medical care. 1992;30(6):473-83. 
8. 
Antonescu I, Carli F, Mayo NE, Feldman LS. Validation of the SF-36 as a measure of 
postoperative recovery after colorectal surgery. Surg Endosc. 2014;28(11):3168-78.