Mathematically Arterialised Testing of Hypercapnic Subjects Study

Study Overview
=================
Brief Summary
-----------------
Prospective observational cohort study of patients admitted to hospital with suspected hypercapnic respiratory failure and requiring treatment with non-invasive ventilation (NIV) as part of standard, routine management. Contemporaneous blood gas samples will be obtained via arterial, capillary, and venous methods. The venous samples will undergo mathematical arterialisation via the v-TAC system. In line with standard medical care, arterial samples will be obtained before starting NIV and at two set points afterwards (day 1 post-NIV, and pre-discharge). Pre-existing clinical thresholds will be used to assess the reliability of v-TAC against ABG, the existing gold standard and will conduct a retrospective model of decision-making once the blood sampling component of the study is concluded.

Official Title
-----------------
A Prospective Observational Cohort Study to Investigate the Physiological Agreement Between Arterial Sampling (the Reference Method) and Mathematically Arterialised Venous Blood

Conditions
-----------------
Hypercapnic Respiratory Failure

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Aged 18 years or above. Admitted for consideration of home Non Invasive Ventilation. Due to undergo arterial blood gas sampling as part of routine clinical care Exclusion Criteria: Inability to provide informed consent. Clinical necessity to perform blood gas sampling prior to allowing sufficient time for informed consent. Inability to obtain reliable SpO2 readings

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in blood carbon dioxide level (PaCO2) | Change in PaCO2 between the pre-NIV (non-invasive ventilation) and day 1 NIV samples for ABG (arterial blood gas) versus v-TAC (arterialised venous blood gas) | Between day 0 and day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in PaCO2 between ABG versus v-TAC versus Capillary Blood Gas (CBG) versus Venous Blood Gas (VBG) | Change in PaCO2 between ABG versus v-TAC versus Capillary Blood Gas (CBG) versus Venous Blood Gas (VBG) between the pre-NIV and day 1 samples | Between day 0 and day 1 | 
| Change in PaCO2 between ABG versus v-TAC versus Capillary Blood Gas (CBG) versus Venous Blood Gas (VBG) | Change in PaCO2 between ABG versus v-TAC versus Capillary Blood Gas (CBG) versus Venous Blood Gas (VBG) between the pre-NIV and pre-discharge samples | Between day 0 and through to study completion, up to 3 days | 
| Relative difficult in sampling | Frequency of sampling error rate for ABG versus CBG versus VBG versus V-TAC | Between day 0 and through to study completion, up to 3 days | 
| Patient experience | Using Numeric Pain Scale where 0 is no pain, 5 is moderate pain and 10 is worst pain possible | Between day 0 and through to study completion, up to 3 days | 
| Patient preference | Patient preference for method of blood gas sampling will be recorded in medical records | Between day 0 and through to study completion, up to 3 days |