Surrogate of Adequate Perfusion: Bladder Tissue Oxygen Monitoring

Study Overview
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Brief Summary
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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.

Detailed Description
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As above

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

Conditions
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Shock, Sepsis, Surgery

Intervention / Treatment
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* Device: WellBeing catheter


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

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

What is the study measuring?
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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 |