Mortality in Intensive Care UnitsRATIO-MIMICNCT07301359
Is the PaO₂/PaCO₂ Ratio Associated With ICU Mortality Independent of Oxygen Saturation and Mean Arterial Pressure?
An observational study of Mortality in Intensive Care Units, run by Tanta University.
Trial summary
The goal of this observational study is to learn about the Association of the PaO₂/PaCO₂ Ratio with ICU Mortality Independent of Oxygen Saturation and Mean Arterial Pressure Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Mortality in Intensive Care Units
- How many people
- 1,776 participants
- Where
- No sites listed yet
- Study dates
- 20 Mar 2015to 20 Mar 2016
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: This study included adult patients admitted to intensive care units (ICUs) represented in the Medical Information Mart for Intensive Care II (MIMIC-II) database, a large, publicly available critical care database developed by the Massachusetts Institute of Technology (MIT) in collaboration with Beth Israel Deaconess Medical Center (BIDMC). The database contains detailed, de-identified clinical data from patients admitted to the BIDMC ICUs between 2001 and 2008. All adult (≥18 years) ICU patients with at least one arterial blood gas measurement containing both arterial oxygen tension (PaO₂) and arterial carbon dioxide tension (PaCO₂) were eligible for inclusion. For each included ICU stay, corresponding measurements of oxygen saturation (SpO₂) and mean arterial pressure (MAP) were also extracted to allow adjustment for oxygenation and hemodynamic status. Patients were excluded if they lacked valid PaO₂ or PaCO₂ measurements, had missing ICU mortality data, or had physiologically impla
Who may be able to join
- Adult patients (≥ 18 years old) at time of ICU admission. Rationale: Restrict to adult physiology and consent/ethics comparability.
- First ICU stay during hospital admission (index ICU admission). Rationale: Avoid within-hospital dependency and repeated measures bias.
- ICU admission captured in the MIMIC-II dataset between the database start and end dates.
- Rationale: Use all eligible records within the dataset timeframe.
- At least one arterial blood gas (ABG) measurement with both PaO₂ and PaCO₂ available during the ICU stay.
- Rationale: Primary exposure is PaO₂/PaCO₂ ratio; require both values to compute it.
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- Available outcome data for ICU mortality (discharge status from ICU). Rationale: Necessary to ascertain primary endpoint.
- Available SpO₂ and mean arterial pressure (MAP) measurements in the same ICU stay (for confounder adjustment).
- Rationale: Study aims to evaluate independence from SpO₂ and MAP; require at least one measurement of each during the stay. (If either is missing, see handling below.)
Who cannot join
- Age < 18 years. Rationale: Exclude pediatric physiology.
- Missing or unusable arterial blood gas values (PaO₂ or PaCO₂ absent or non-numeric) for the ICU stay.
- Rationale: Cannot compute exposure.
- No recorded ICU outcome (missing ICU discharge status) or lost/invalid mortality data.
- Rationale: Cannot determine primary outcome.
- Extreme or physiologically implausible ABG values that suggest data error (e.g., PaO₂ ≤ 0 mmHg, PaCO₂ ≤ 0 mmHg, or PaO₂ > 1000 mmHg or PaCO₂ > 300 mmHg - thresholds may be tightened after exploratory data review).
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- Rationale: Remove likely data-entry errors. Document thresholds and perform sensitivity analysis.
- Patients on extracorporeal life support (ECMO) during ABG measurement (if identifiable in MIMIC-II).
- Rationale: ECMO profoundly alters gas exchange and PaO₂/PaCO₂ physiology; consider exclusion or separate subgroup.
- Repeat ICU admissions within the same hospital stay beyond the index admission (if you choose to restrict to single index admission).
- Rationale: Prevent correlated observations - include only the first ICU stay per hospital admission.
- ICU stays with no recorded SpO₂ or MAP at any time (if you insist on requiring these for adjustment).
- Rationale: If primary models must adjust for SpO₂ and MAP, exclude records without those covariates or plan appropriate imputation.
- Do-not-resuscitate (DNR)/comfort-care only status recorded before ABG measurement (optional exclusion depending on study question).
- Rationale: Treatment limitation orders can confound mortality associations; you may choose instead to adjust or analyze separately.
About this study
Official title: Association of the PaO₂/PaCO₂ Ratio With ICU Mortality Independent of Oxygen Saturation and Mean Arterial Pressure: Insights From the MIMIC-II Database
The goal of this observational study is to learn about the Association of the PaO₂/PaCO₂ Ratio with ICU Mortality Independent of Oxygen Saturation and Mean Arterial Pressure
- Conditions
- Mortality in Intensive Care Units
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| The Indwelling Arterial Catheter Clinical dataset contains clinical data for 1776 patients.......... | The Indwelling Arterial Catheter Clinical dataset contains clinical data for 1776 patients from the MIMIC-II clinical database. It was the basis for the article: Hsu DJ, et al. The association between indwelling arterial catheters and mortality in hemodynamically stable patients with respiratory failure: A propensity score analysis. Chest, 148(6):1470-1476, Aug. 2015.This dataset was also used by Raffa et al. in Chapter 5 "Data Analysis" of the forthcoming book: Secondary Analysis of Electronic Health Records, published by Springer in 2016...................................................................................................................................................................................................................................................................................................................................................................................................................................................................... |
What is being measured
The primary outcome is the main question the study is designed to answer.
ICU mortality
Death occurring during the ICU stay
Measured: From October 2025 to January 2026.............................................................................................................................................................................................................................
Secondary outcomes (1)
28-day all-cause mortality
28-day all-cause mortality
Measured: From October 2025 to January 2026
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Dec 2025
- Study start20 Mar 2015
- Primary completion20 Mar 2016
- Study completion20 Mar 2016
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Mortality in Intensive Care UnitsStudies of the same condition, open and under way.
- More trials run by Tanta UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 1,776 participants (actual)
Sponsor and investigators
- Lead sponsor
- Tanta University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, MOHAMMED FAWZI ALI ABOSAMAK, Tanta University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07301359
- Sponsor's protocol ID
- MIMIC-II
- Acronym
- RATIO-MIMIC
- Status last verified
- Dec 2025
- First submitted
- 10 Dec 2025
- Last updated
- 24 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Association of the PaO₂/PaCO₂ Ratio With ICU Mortality Independent of Oxygen Saturation and Mean Arterial Pressure: Insights From the MIMIC-II Database
- ClinicalTrials.gov ID
- NCT07301359
- Acronym / sponsor ID
- RATIO-MIMIC / MIMIC-II
- Conditions
- Mortality in Intensive Care Units
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 1,776 participants (actual)
- Lead sponsor
- Tanta UniversityUniversity, hospital or other
- Study start
- 20 Mar 2015 (actual)
- Primary completion
- 20 Mar 2016 (actual)
- Study completion
- 20 Mar 2016 (actual)
- First posted
- 24 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational study is to learn about the Association of the PaO₂/PaCO₂ Ratio with ICU Mortality Independent of Oxygen Saturation and Mean Arterial Pressure
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| The Indwelling Arterial Catheter Clinical dataset contains clinical data for 1776 patients.......... | – | –The Indwelling Arterial Catheter Clinical dataset contains clinical data for 1776 patients from the MIMIC-II clinical database. It was the basis for the article: Hsu DJ, et al. The association between indwelling arterial catheters and mortality in hemodynamically stable patients with respiratory failure: A propensity score analysis. Chest, 148(6):1470-1476, Aug. 2015.This dataset was also used by Raffa et al. in Chapter 5 "Data Analysis" of the forthcoming book: Secondary Analysis of Electronic Health Records, published by Springer in 2016...................................................................................................................................................................................................................................................................................................................................................................................................................................................................... |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- This study included adult patients admitted to intensive care units (ICUs) represented in the Medical Information Mart for Intensive Care II (MIMIC-II) database, a large, publicly available critical care database developed by the Massachusetts Institute of Technology (MIT) in collaboration with Beth Israel Deaconess Medical Center (BIDMC). The database contains detailed, de-identified clinical data from patients admitted to the BIDMC ICUs between 2001 and 2008. All adult (≥18 years) ICU patients with at least one arterial blood gas measurement containing both arterial oxygen tension (PaO₂) and arterial carbon dioxide tension (PaCO₂) were eligible for inclusion. For each included ICU stay, corresponding measurements of oxygen saturation (SpO₂) and mean arterial pressure (MAP) were also extracted to allow adjustment for oxygenation and hemodynamic status. Patients were excluded if they lacked valid PaO₂ or PaCO₂ measurements, had missing ICU mortality data, or had physiologically impla
Key inclusion criteria (9 listed)
- Adult patients (≥ 18 years old) at time of ICU admission. Rationale: Restrict to adult physiology and consent/ethics comparability.
- First ICU stay during hospital admission (index ICU admission). Rationale: Avoid within-hospital dependency and repeated measures bias.
- ICU admission captured in the MIMIC-II dataset between the database start and end dates.
- Rationale: Use all eligible records within the dataset timeframe.
- At least one arterial blood gas (ABG) measurement with both PaO₂ and PaCO₂ available during the ICU stay.
Key exclusion criteria (15 listed)
- Age < 18 years. Rationale: Exclude pediatric physiology.
- Missing or unusable arterial blood gas values (PaO₂ or PaCO₂ absent or non-numeric) for the ICU stay.
- Rationale: Cannot compute exposure.
- No recorded ICU outcome (missing ICU discharge status) or lost/invalid mortality data.
- Rationale: Cannot determine primary outcome.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
ICU mortality
Time frame: From October 2025 to January 2026.............................................................................................................................................................................................................................
Death occurring during the ICU stay
1 secondary outcome
28-day all-cause mortality
Time frame: From October 2025 to January 2026
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Dec 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
An observational study of Mortality in Intensive Care Units, run by Tanta University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 24 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
ICU mortality (time frame: From October 2025 to January 2026.............................................................................................................................................................................................................................). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Dec 2025.