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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Sequential compression alone for the prevention of deep venous thrombosis in operating theatres
Scientific title
Sequential compression alone for the prevention of deep venous thrombosis in operating theatres (SoCS-FREE-OT) for patients undergoing emergency or elective laparoscopic cholecystectomy
Secondary ID [1] 304844 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Deep Venous Thrombosis 322931 0
Laparoscopic Cholecystectomy 323306 0
Pulmonary Embolism 323307 0
Condition category
Condition code
Surgery 320508 320508 0 0
Other surgery
Cardiovascular 320870 320870 0 0
Other cardiovascular diseases
Oral and Gastrointestinal 320871 320871 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon
Respiratory 320872 320872 0 0
Other respiratory disorders / diseases

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
This is a prospective point prevalence, surgical comparative effectiveness study of patients undergoing either an emergency or elective laparoscopic cholecystectomy.

It is a requirement of the study that any participating hospital has already adopted or is trialing the protocol of routine Sequential Calf Compression Devices (SCCDs) alone for laparoscopic cholecystectomy prior to data collection, and that this decision is made on clinical grounds and not for the purposes of research. All patients requiring either an elective or an emergency laparoscopic cholecystectomy will be recruited into this study.

For those participants who are booked for an elective laparoscopic cholecystectomy, they will be admitted to the hospital on the day of their surgery. A sequential calf compressor device will be fitted as per manufacturer’s specifications by the trained theatre technician, immediately prior to the commencement of surgery and will be used for the duration of surgery (approximately 1 hour), performed by or under the supervision of a consultant general surgeon. At the completion of surgery and immediately before the patient is transferred to the post anaesthetic care unit (PACU), the SCCDs will be removed. Chemical thromboprophylaxis will be initiated by the subcutaneous injection of 40 mg of enoxaparin, 5,000 IU of dalteparin or 5,000 IU of heparin at any time at the discretion of the treating team. Subsequent does of enoxaparin and dalteparin (if required) are given 24 hours later following the initial dose. The dosing of enoxaparin is to be based on BMI and renal function only. For those patients whose Body Mass Index (BMI) is less than 40, use 40 mg once daily (OD), for those patients whose BMI is equal to or greater than 40, use 40 mg twice daily, with the second dose being given 12 hours after the initial dose. For those patients with chronic renal disease, with a creatinine clearance of less than 30 mL/minute, a renal adjusted dose will be given. For those patients receiving heparin, the second dose will be given 12 hours post the initial dose. No participant undergoing an elective operation is to have Graduated Compression Stockings (GCSs) fitted either pre- or post-operatively. Participants may be discharged home on the day of their surgery, or after an overnight hospital stay, at the discretion of their treating surgeon. During the operation, positioning of the patient and the intra-abdominal insufflation pressure will be at the discretion of the treating surgeon.

For those participants who are undergoing an emergency laparoscopic cholecystectomy, access to theatre may differ across the various hospital campuses. This will be controlled for by the acquisition of data pertaining to the length of time of admission to the hospital, relative to the timing of their actual surgery. For these patients, it is anticipated that they will have received chemical thromboprophylaxis prior to their operation. This data will be collected and analysed separately as a sub-analysis. There will be no restrictions on the type and timing of chemical thromboprophylaxis used. These patients are allowed to have GCSs fitted pre-operatively. However, these GCSs will be removed when the patient presents to the operating theatre and the use of GCSs post-operatively is contraindicated. SCCDs will be applied as per the manufacturer's instructions by the trained theatre technician. The operation will be performed or supervised by a consultant general surgeon. Demographic and operative data will be collected at the end of the operation by the surgical fellow/registrar/resident who has been recruited to the study and trained under the auspices of the WestSURG collaborative. This process will also be supervised by the PI from each institution.

All participants may be seen post-operatively in surgical outpatient clinics at the discretion of the treating surgeons. This clinic appointment may be face to face, or conducted via telephone or telehealth. At this visit, symptoms of Venous Thromboembolism (VTE) may be enquired about, and if suggestive of a VTE, image confirmation may be obtained. As part of this study, all patients will be contacted between day 30 and 35 post-operatively via telephone to enquire about symptoms that may be suggestive of the development of VTE, irrespective of the clinical follow-up. Post-operative morbidity will also be sought via this phone process, as well as review of the patient's file. The process of the phone questionnaire will include a verbal consent. This process will occupy approximately 2 – 5 minutes of their time and involves a fixed set of questions that are verbally asked for each participant regarding any morbidity or symptoms of VTE with results recorded by the researcher straight on to a REDCap database. For those participants who have symptoms suggestive of a VTE, they will be referred back to their treating hospital via the Emergency Department for image confirmation of VTE which may include bilateral leg ultrasound if experiencing symptoms of deep venous thrombosis, or computed tomography pulmonary angiogram if experiencing symptoms of pulmonary embolism. If VTE is confirmed, then an anticoagulation regime will be commenced at the discretion of the clinical team, the duration of which is guided by the latest guidelines from the Thrombosis and Haemostasis Society of Australia and New Zealand (Tran et al., 2019).
Intervention code [1] 321226 0
Not applicable
Comparator / control treatment
There is no control group in this study. Comparator group will be a previously reported group of 1100 patients in the PROTECTing study (ANZ J Surg 90 (2020) 2449–2455). This control group are the patients who underwent elective cholecystectomy from 1 January 2018 to 30 June 2019 at seven Victorian hospitals in Australia, and whom have received both GCS and SCCDs as mechanical VTE prophylaxis.
Control group

Primary outcome [1] 328340 0
This is a composite primary outcome of the detection of a post-operative Deep Venous Thrombosis (DVT) or Pulmonary Embolus (PE), as confirmed by either bilateral leg ultrasound or computed topography pulmonary angiogram.
Timepoint [1] 328340 0
30 days post-operatively.
Secondary outcome [1] 398641 0
A composite secondary outcome is post-operative morbidity (including surgical bleeding, infection, unexpected ICU admission, organ failure) as recorded by either 30 day post-operative phone questionnaire, or through a review of the patient notes at the same time point (both of which will be performed).
Timepoint [1] 398641 0
30 days post-operatively.
Secondary outcome [2] 399879 0
A secondary outcome is length of stay as recorded through a review of the patient notes at the 30 day-post-operative time point.
Timepoint [2] 399879 0
30 days post-operatively.
Secondary outcome [3] 399880 0
A secondary outcome is duration of surgery as recorded by the researcher (surgical registrar) at the completion of the operation
Timepoint [3] 399880 0
Immediately post-operatively.
Secondary outcome [4] 399881 0
A secondary outcome is chemical thromboprophylaxis administered as recorded through a review of the patient notes at the 30 day-post-operative time point.
Timepoint [4] 399881 0
30 days post-operatively.

Key inclusion criteria
All patients who undergo a laparoscopic cholecystectomy either as an emergency or elective procedure at each of the hospital campuses are eligible for inclusion in this study. All of the involved hospitals have either already adopted SCCDs alone, or are in the process of either permanently adopting or performing an internal trial using this study’s protocols. It is a requirement of this study that all involved hospitals have adopted this protocol prior to the commencement of data collection, in order that this study is a true cohort study.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Participants will be excluded for the following criteria:
• If they are fitted with GCSs exclusively, combined GCSs and SCCDs, or no mechanical prophylaxis is used intra-operatively.
• A planned or unplanned conversion to open cholecystectomy.
• Under the age of 18 years

Study design
Natural history
Defined population
Statistical methods / analysis
Descriptive statistics will be prepared to provide a summary of the cohort. The incidence rate of VTE and surgical bleeding will be calculated. If the sample size allows, associations between patient and surgical factors with the primary and secondary outcomes will be performed using appropriate continuous or categorical statistical tests. Given the expected low incident rate of VTE, multivariable analysis is likely to be limited to the inclusion of two variables to assess potential confounding effects. The potential higher incident rate of surgical bleeding will allow up to 10 variables to be included, according to sample size calculations indicated by Peduzzi et al. 1996.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 20046 0
The Northern Hospital - Epping
Recruitment hospital [2] 20047 0
Western Hospital - Footscray - Footscray
Recruitment hospital [3] 20048 0
Sunshine Hospital - St Albans
Recruitment hospital [4] 20049 0
Monash Medical Centre - Clayton campus - Clayton
Recruitment hospital [5] 20050 0
Barwon Health - Geelong Hospital campus - Geelong
Recruitment hospital [6] 20051 0
Royal Melbourne Hospital - City campus - Parkville
Recruitment hospital [7] 20052 0
Nepean Hospital - Kingswood
Recruitment hospital [8] 20053 0
John Hunter Hospital - New Lambton
Recruitment hospital [9] 20054 0
Flinders Medical Centre - Bedford Park
Recruitment hospital [10] 20055 0
The Royal Adelaide Hospital - Adelaide
Recruitment postcode(s) [1] 34753 0
3076 - Epping
Recruitment postcode(s) [2] 34754 0
3011 - Footscray
Recruitment postcode(s) [3] 34755 0
3021 - St Albans
Recruitment postcode(s) [4] 34756 0
3168 - Clayton
Recruitment postcode(s) [5] 34757 0
3220 - Geelong
Recruitment postcode(s) [6] 34758 0
3050 - Parkville
Recruitment postcode(s) [7] 34759 0
2747 - Kingswood
Recruitment postcode(s) [8] 34760 0
2305 - New Lambton
Recruitment postcode(s) [9] 34761 0
5042 - Bedford Park
Recruitment postcode(s) [10] 34762 0
5000 - Adelaide

Funding & Sponsors
Funding source category [1] 309216 0
Name [1] 309216 0
Northern Health
Address [1] 309216 0
185 Cooper St
Northern Health
Epping 3076
Country [1] 309216 0
Primary sponsor type
Northern Health
185 Cooper St
Northern Health
Epping 3076
Secondary sponsor category [1] 310178 0
Name [1] 310178 0
Address [1] 310178 0
Country [1] 310178 0

Ethics approval
Ethics application status
Ethics committee name [1] 309067 0
St Vincent's Hospital Melbourne HREC
Ethics committee address [1] 309067 0
Research Governance Unit
St Vincent's
PO Box 2900
Fitzroy 3065
Ethics committee country [1] 309067 0
Date submitted for ethics approval [1] 309067 0
Approval date [1] 309067 0
Ethics approval number [1] 309067 0
LRR 094/21

Brief summary
Venous thromboembolism (VTE) is a condition whereby a blood clot forms inappropriately in the veins. This clot may dislodge from its point of origin and be carried to the lung vasculature, which may be a fatal event. It has been estimated that the Australian annual incidence of VTE is 0.83 per 1000 individuals and is associated with significant morbidity and health related economic costs. In 2008, the estimated cost to the Australian economy was $1.7 billion dollars. Venous thromboembolism may be provoked by major surgery. The risk of surgically provoked VTE may be mitigated by the combined use of mechanical thromboprophylaxis, as recommended by the 2012 American College of Chest Physicians (ACCP) clinical practice guidelines and more recently, the 2019 American Society of Hematology (ASH) clinical practice guidelines. Despite this, there is no clear recommendation as to the type of mechanical thromboprophylaxis that should be used, with either or both graduated compression stockings (GCSs) or sequential calf compression devices (SCCDs) used.

We wish to perform a cohort study of all laparoscopic cholecystectomies (elective and emergency) with a standardized mechanical prophylaxis protocol, to determine if we can maintain a low rate of VTE on SCCDs alone compared with the historical cohort of patients managed with combined SCCDs and GCSs, whilst maintaining safety including the risk of bleeding.

The hypothesis of this study is that there is no difference between combined SCCDs and GCSs when compared with SCCDs alone. If this is true, GCSs could be removed from normal care, reducing GCS related complications and producing substantial cost savings for hospitals.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 112854 0
Mr Russell Hodgson
Address 112854 0
Department of Surgery
Northern Health
185 Cooper St
Epping 3076
Country 112854 0
Phone 112854 0
+613 8405 2593
Fax 112854 0
Email 112854 0
Contact person for public queries
Name 112855 0
Mr Russell Hodgson
Address 112855 0
Department of Surgery
Northern Health
185 Cooper St
Epping 3076
Country 112855 0
Phone 112855 0
+613 8405 8000
Fax 112855 0
Email 112855 0
Contact person for scientific queries
Name 112856 0
Mr Russell Hodgson
Address 112856 0
Department of Surgery
Northern Health
185 Cooper St
Epping 3076
Country 112856 0
Phone 112856 0
+613 8405 8000
Fax 112856 0
Email 112856 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Data will be deidentified and individual participant data will not be publicly available. Collective data will be presented in peer reviewed publications and further access to data can be directed to the study PI. De-identified individual participant data will not be available due to current health institution and ethical agreements.
What supporting documents are/will be available?
Study protocol
How or where can supporting documents be obtained?
Type [1] 12628 0
Study protocol
Citation [1] 12628 0
Link [1] 12628 0
Email [1] 12628 0
Other [1] 12628 0
Summary results
No Results