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Plain English Summary

Background and study aims
Emergency bowel surgery (laparotomy) is a major procedure which can lead to reduced blood flow to vital organs. This can lead to complications after surgery. Fluids are given into the bloodstream (intravenous) to improve blood flow. Giving the right amount of this intravenous fluid at the right time is important for recovery after surgery, but is hard to gauge accurately. Doctors normally use signs such as heart rate and blood pressure to guide them, but these can be unreliable. Previous research has shown that a treatment used during surgery and shortly afterwards may improve the amount of oxygen delivered to the body’s tissues and reduce the number of patients who develop complications after surgery. This treatment involves using a heart monitor (cardiac output monitor) to help clinical teams decide the amount and timing of intravenous fluid to give to patients. There is some evidence from smaller studies that this treatment is beneficial, but this needs to be confirmed in a much larger study. The aim of this study is to find out whether the use of cardiac output monitoring to guide the use of intravenous fluid reduces mortality (death rates) compared with usual care.

Who can participate?
Patients aged 50 and over undergoing emergency laparotomy

What does the study involve?
During and after surgery, participants are randomly allocated to receive one of treatments, either the study treatment or usual care. Participant experience is the same regardless of which treatment they receive, and they probably won’t be able to tell which one they are getting. Both treatments begin at the start of surgery and finish six hours after it has ended. The two treatments involve slightly different ways of deciding the amount of intravenous fluid participants receive. If they receive usual care their doctor uses measurements such as heart rate and blood pressure to guide this. If they receive the new study treatment their clinical team also measures the amount of blood their heart pumps each minute using an extra monitor. These extra measurements help the doctor to decide how much intravenous fluid they give. After the treatment is over, care continues as normal and there is no need to contact the participants further. Routinely collected information from medical notes and NHS databases is used to follow up participant recovery after surgery.

What are the possible benefits and risks of participating?
Previous research suggests that the treatment is safe and should benefit most patients. Participants are closely monitored throughout the study and, if necessary, their clinical team makes adjustments to their treatment to make sure they are safe.

Where is the study run from?
100 hospitals in the UK, led by Southampton General Hospital

When is the study starting and how long is it expected to run for?
May 2017 to January 2022

Who is funding the study?
Health Technology Assessment Programme (UK)

Who is the main contact?
Mrs Jade Rand

Trial website

Contact information



Primary contact

Mrs Jade Rand


Contact details

Critical Care/Anaesthesia & Perioperative Medicine Research Unit
Rm CE93 Mailpoint 24
University Hospital Southampton NHS Foundation Trust
Southampton General Hospital
Tremona Road
SO16 6YD
United Kingdom
+44 (0)238 120 5308



Additional contact

Dr Mark Edwards


Contact details

University Hospital Southampton
SO16 6YD
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number

CRI0336; HTA 15/80/54

Study information

Scientific title

FLuid Optimisation in Emergency LAparotomy (FLO-ELA): an open, multi-centre, randomised controlled trial of cardiac output-guided haemodynamic therapy compared to usual care in patients undergoing emergency bowel surgery



Study hypothesis

To establish whether the use of minimally invasive cardiac output monitoring to guide protocolised administration of intra-venous fluid (goal-directed haemodynamic therapy, GDHT), for patients aged 50 and over undergoing emergency laparotomy will reduce mortality within 90 days of randomisation, when compared with usual care.

Ethics approval

London - Bromley Research Ethics Committee, 28/03/2017, ref: 17/LO/0334

Study design

Randomised controlled trial with open study group allocation and internal pilot study, supported by ongoing data collection from the National Emergency Laparotomy Audit (NELA)

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details to request a patient information sheet


Surgery - emergency laparotomy


The trial treatment period will commence at the start of general anaesthesia and continue for six hours after the completion of surgery. Eligible patients will be randomised to receive either cardiac-output guided haemodynamic therapy (intervention group), or usual care (control group). Perioperative management for all patients during the trial treatment period will be in accordance with recommended guidance.

Intervention: Treatment algorithm guided by cardiac output monitoring to determine dose and timing of intravenous fluid. Clinicians may choose from a range of cardiac output monitors in established use which have been shown to track changes in cardiac stroke volume accurately. 250ml aliquots of crystalloid or colloid solution will be administered according to the algorithm to achieve and maintain an optimal value of stroke volume. This intervention supplements but does not replace the monitoring used for conventional clinical assessments. The protocol allows the treating clinician to adjust the volume and type of fluid administered, e.g. if there is concern about persistent hypovolaemia or fluid overload.

Control: Usual care, with intravenous fluid given according to conventional clinical assessment without the use of cardiac output monitoring or algorithm.

Intervention type



Drug names

Primary outcome measure

Mortality within 90 days of randomisation, using mortality data from NHS Digital/Office for National Statistics (or equivalents)

Secondary outcome measures

Mortality within one year of randomisation, using mortality data from NHS Digital/Office for National Statistics (or equivalents)

Process outcomes:
1. Duration of hospital stay, from data entered into the National Emergency Laparotomy Audit (NELA) by teams in each participating hospital
2. Duration of stay in a critical care bed within the primary hospital admission, from data entered into NELA by teams in each participating hospital
3. Hospital readmission as an inpatient (overnight stay) within 90 days from randomisation, using data from NHS Digital/Hospital Episode Statistics (or equivalents)

Health economic endpoints:
1. Mean cost of implementing the intervention and control treatments
2. Mean cost of secondary care resource use within 90 days from randomisation
3. Quality-adjusted life year gain at 90 days from randomisation using EQ-5D-3L-derived utility scores at baseline and 90 day follow-up (estimated from preceding EPOCH trial data – no EQ-5D-3L data collection will be required within the FLO-ELA trial)

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Age 50 years and over
2. Scheduled to undergo a surgical procedure which fulfils the criteria for entry into the National Emergency Laparotomy Audit (NELA), i.e. an expedited, urgent or emergency abdominal procedure on the gastrointestinal tract within the audit scope, including:
2.1. Procedures involving the stomach, small or large bowel, or rectum for conditions such as perforation, ischaemia, abdominal abscess, bleeding or obstruction
2.2. Washout/evacuation of intra-peritoneal abscess (unless due to appendicitis or cholecystitis)
2.3. Bowel resection/repair due to incarcerated umbilical, inguinal and femoral hernias (but not hernia repair without bowel resection/repair)
2.4. Return to theatre for repair of substantial dehiscence of major abdominal wound (i.e. ‘burst abdomen’) or after patients underwent non-elective gastro-intestinal surgery
3. Patient has an NHS number
The term “emergency” laparotomy is defined in line with NELA and the National Confidential Enquiry into PeriOperative Deaths (NCEPOD) 2004, to encompass the following categories: “immediate” surgery (required within two hours of the decision to operate), “urgent” surgery (required within 2-18 hours of the decision to operate) and “expedited” surgery (required within 18-24 hours of the decision to operate)

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Refusal of patient consent
2. Clinician refusal
3. Previous enrolment in the FLO-ELA trial
4. Previous inclusion in NELA within the current hospital admission
5. Current participation in another clinical trial of a treatment with a similar biological mechanism
6. Scheduled abdominal procedure outside the scope of NELA, including: elective procedures, uncomplicated appendicectomy or cholecystectomy, non-elective hernia repair without bowel resection, vascular surgery, including abdominal aortic aneurysm repair, Caesarean section, obstetric laparotomies or gynaecological laparotomy, or laparotomy/laparoscopy for pathology caused by trauma

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Southampton General Hospital
SO16 6YD

Trial participating centre

Russells Hall Hospital

Trial participating centre

Derriford Hospital

Trial participating centre

Royal Free Hospital

Trial participating centre

Medway Maritime Hospital

Trial participating centre

City Hospital (Sandwell)
B18 7QH

Trial participating centre

Glan Clwyd Hospital
LL18 5UJ

Trial participating centre

Royal Gwent Hospital
NP20 2UB

Trial participating centre

Harrogate District Hospital

Trial participating centre

Warwick Hospital
CV34 5BW

Trial participating centre

Great Western Hospital

Trial participating centre

Luton and Dunstable University Hospital

Trial participating centre

Musgrove Park Hospital

Trial participating centre

Birmingham Heartlands Hospital
B9 5ST

Trial participating centre

Royal Preston Hospital

Trial participating centre

Hampshire Hospitals NHS Foundation Trust
RG24 9NA

Trial participating centre

Wye Valley NHS Trust

Trial participating centre

Northampton General Hospital

Trial participating centre

Queen Alexandra Hospital

Trial participating centre

Tameside General Hospital

Trial participating centre

Lister Hospital

Trial participating centre

Chelsea & Westminster Hospital
SW10 9NH

Trial participating centre

Sherwood Forest Hospitals
NG17 4JL

Trial participating centre

James Paget University Hospital
NR31 6LA

Trial participating centre

Torbay Hospital

Trial participating centre

Conquest Hospital
TN37 7PT

Trial participating centre

East Surrey Hospital

Trial participating centre

Amersham Hospital

Trial participating centre

Leighton Hospital

Trial participating centre

Royal Berkshire Hospital

Trial participating centre

Basildon Hospital
SS16 5NL

Sponsor information


University Hospital Southampton NHS Foundation Trust

Sponsor details

Southampton General Hospital
Tremona Road
SO16 6YD
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type


Funder name

Health Technology Assessment Programme

Alternative name(s)

NIHR Health Technology Assessment Programme, HTA

Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

1. Final Report to funder - March 2022
2. Planned publication in a high impact peer reviewed journal - summer 2022
3. Conferences and meetings - 2022 - ongoing

IPD sharing plan
The datasets generated during and/or analysed during the current study will be available upon request from Any data sharing requests will be subject to the Pragmatic Clinical Trials Unit data sharing policy.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes