Surrogate of Adequate Perfusion: Bladder Tissue Oxygen Monitoring (SoAP-BOx)

An Observational Study of Tissue Oxygen Monitoring for Detecting Impending Shock States in the Critically Ill and Those Undergoing High Risk Surgery

The extent and duration of tissue hypoxia is a major determinant of outcome following major, high-risk surgery and in critical illness. Prompt restoration of tissue oxygenation through resuscitation in all likelihood improves outcomes. There are currently no bedside monitors in clinical practice that track tissue perfusion per se, instead clinicians rely on crude surrogates such as heart rate and blood pressure, urine output, serum lactate of global flow (cardiac output) monitoring.

This is a first-in-man trial of a new device to measure tissue oxygenation in real time in a major, high-risk surgical and critical care cohort. The device consists of an oxygen sensing probe incorporated into a modified urinary catheter, which relies on photoluminescence technology and the quenching properties of oxygen.

Once inserted, the drained bladder collapses round and envelopes the probe which continuously measures tissue oxygenation of the bladder urothelium.

The investigators hope to (i) Establish that tissue oxygenation can be safely monitored using this technology, deployed in this way. (ii) Define a normal range for bladder tissue oxygenation in man as measured using this device. (iii) Compare tissue oxygenation against other markers of perfusion status in current clinical practice and assess its performance at detecting inadequate perfusion against these other modalities. (iv) assess the diagnostic and prognostic capabilities of the tissue oxygenation monitoring at detecting hypo-perfusion and predicting outcome. (v) Further assess the tissue response to an 'oxygen challenge' in identifying occult hypo-perfusion. (vi). Provide pilot work required to inform future, interventional studies where similar patients would be resuscitated to tissue oxygenation targets alongside routine clinical practice.

Study Overview

• Status: Unknown
• Conditions: Sepsis; Shock; Surgery
• Intervention / Treatment: Device: WellBeing catheter

Detailed Description

As above

• Study Type: Observational
• Enrollment (Anticipated): 315

Contacts and Locations

• Study Contact: Name: Mervyn Singer, MB BS; Phone Number: +44-207-679-6714; Email: m.singer@ucl.ac.uk
• Study Contact Backup: Name: David Brealey, MB BS; Email: d.brealey@nhs.net

Study Locations

• United Kingdom
  • London, United Kingdom, NW1
    • Recruiting
    • UCL Hospitals NHS Foundation Trust
    • Contact: Mervyn Singer, MD FRCP; Phone Number: +44 207 679 9666; Email: m.singer@ucl.ac.uk
    • Contact: David Brealey, FRCA FFICM; Phone Number: +44 203 447 3363; Email: d.brealey@nhs.net

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

as described above

Description

Inclusion Criteria:

• having major elective or emergency surgery (deemed to need invasive BP monitoring by anaesthetist) and a urinary catheter
• OR emergency admission to critical care (necessitating arterial line and urinary catheter).

Exclusion Criteria:

• age <18
• pregnancy
• contraindication to arterial cannulation or urethral catheterisation
• surgery on lower urinary tract/bladder
• patient refusal

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
High risk surgery; those undergoing elective and emergency, high-risk surgery receiving arterial cannulation and urethral catheterisation as standard	Device: WellBeing catheter; Urethral catheterisation with integral Wellbeing Catheter to measure bladder tissue oxygen tension
Critical Care; Emergency admissions to UCLH critical care unit receiving arterial cannulation and urethral catheterisation as standard	Device: WellBeing catheter; Urethral catheterisation with integral Wellbeing Catheter to measure bladder tissue oxygen tension

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to identification of a low bladder tissue PO2 versus time to development of hyperlactatemia (2 mmol/l)	Comparison of bladder tissue PO2 values (normal range to be defined as part of this first-in-man study) against lactate values >2 mmol/l	Up to 7 days
Time to identification of a low bladder tissue PO2 versus time to development of hypotension (mean BP <60 mmHg)	Comparison of bladder tissue PO2 values (normal range to be defined as part of this first-in-man study) against mean BP values <60 mmHg	Up to 7 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Device-Related Adverse Events	Monitoring of direct device-related complications (e.g. bleeding, bladder perforation)	Up to 28 days
Identification of future complications in postoperative patients	Low bladder tissue PO2 values identify postoperative complications using POMS-score-defined morbidity at Days 3 and 7	Up to 7 days

Collaborators and Investigators

• Sponsor: University College London Hospitals
• Collaborators: Wellcome Trust; Department of Health, United Kingdom
• Investigators: Principal Investigator: Mervyn Singer, MD, UCL

Study record dates

Study Major Dates

• Study Start (Actual): April 10, 2019
• Primary Completion (Anticipated): February 1, 2020
• Study Completion (Anticipated): March 1, 2020

Study Registration Dates

• First Submitted: March 13, 2019
• First Submitted That Met QC Criteria: May 1, 2019
• First Posted (Actual): May 2, 2019

Study Record Updates

• Last Update Posted (Actual): May 2, 2019
• Last Update Submitted That Met QC Criteria: May 1, 2019
• Last Verified: May 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Shock
• Other Study ID Numbers: CIP_DPW016_OBS

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No