Ignite Creation Date:
2025-12-24 @ 5:23 PM
Ignite Modification Date:
2025-12-27 @ 1:28 PM
Study NCT ID:
NCT02599350
Status:
COMPLETED
Last Update Posted:
2015-11-06
First Post:
2009-04-30
Is NOT Gene Therapy:
True
Has Adverse Events:
False
Brief Title:
Assessing Gas Exchange in Intensive Care Patients on a Ventilator
Sponsor:
University of Aberdeen
Organization:
Study Overview
Official Title:
Evaluation of a New Computer Slide Rule Method for Assessing Gas Exchange in Intensive Care Patients on a Ventilator
Status:
COMPLETED
Status Verified Date:
2015-11
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
In an attempt to standardise the degree of impairment of gas exchange in the lungs of ICU patients a number of indices of oxygen exchange have been developed. These include: the arterial-alveolar oxygen tension ratio (a/APO2), the arterial oxygen tension-inspired oxygen concentration ratio (PaO2/FIO2), the respiratory index (RI), \[A-a)DO2/PaO2) and the alveolar-arterial oxygen tension difference \[A-a)DO2). These are used clinically despite the fact that they do not accurately predict gas exchange particularly with changing the amount of inspired oxygen or when there is mixing of oxygenated blood with unoxygenated blood in the patient (called shunt). None of the indices reliably reflect the behaviour of the physiological shunt. In a pilot study as inspired oxygen (FIO2) was increased incrementally from 0.30 to 1.00, up to 55 per cent of the measured changes in these indices were opposite in direction to the corresponding changes in the physiological shunt. The investigators have developed a computer algorithm and a slide rule to try and improve on these clinical measures. The investigators wish to test their slide rule on ventilated patients by altering the inspired oxygen to see if it will predict what the actual change in oxygen will be.
Detailed Description:
30 adult patients admitted to Aberdeen Royal Infirmary ICU, requiring invasive mechanical ventilation and with impaired gas exchange will be recruited and the following baseline demographic data will be recorded: cause of respiratory failure, APACHE II score, cardiovascular shock (presence / absence), duration of mechanical ventilation prior to inclusion, duration of respiratory failure prior to inclusion. Also the following baseline physiological data will also be recorded: FIO2, SaO2, PEEP, arterial blood pressure, central venous pressure, haemoglobin, PaO2, PaCO2, arterial pH and inotrope / vasopressor infusion rates.
The FIO2 will then be varied in random steps to 0.35, 0.4, 0.45, 0.5, 0.55, 0.6 and 0.65. After changing the FIO2 a 3-4 minute equilibration period will be allowed prior to taking an arterial blood gas sample for analysis. In the event of a PaO2 \< 8kPa being recorded, further reductions in FIO2 will not be undertaken.
The data collected will then be utilised using a slide rule computer programme to generate FIO2 vs. SpO2 graphs. Other indices of gas exchange, e.g. PaO2/FIO2 ratios will also be generated from the data. Predicted versus actual PaO2 will be plotted and a correlation coefficient obtained.
Patients will then be followed for up to 5 days and depending on progression the same procedures will be repeated between days 3 and 5.
The FIO2 will then be varied in random steps to 0.35, 0.4, 0.45, 0.5, 0.55, 0.6 and 0.65. After changing the FIO2 a 3-4 minute equilibration period will be allowed prior to taking an arterial blood gas sample for analysis. In the event of a PaO2 \< 8kPa being recorded, further reductions in FIO2 will not be undertaken.
The data collected will then be utilised using a slide rule computer programme to generate FIO2 vs. SpO2 graphs. Other indices of gas exchange, e.g. PaO2/FIO2 ratios will also be generated from the data. Predicted versus actual PaO2 will be plotted and a correlation coefficient obtained.
Patients will then be followed for up to 5 days and depending on progression the same procedures will be repeated between days 3 and 5.
Study Oversight
Has Oversight DMC:
False
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?: