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Case Report03-19-2025
Prediction of PaO2 from SpO2 values in critically ill invasively ventilated patients: rationale and protocol for a patient–level analysis of ERICC, LUNG SAFE, PRoVENT and PRoVENT–iMiC (PRoPERLy II)
- Simon Corrado Serafini
, - David M. P. van Meenen ,
- Luigi Pisani ,
- Ary Serpa Neto ,
- Luciano César Pontes Azevedo , [ ... ],
- Guido Mazzinari
Abstract
Case ReportPrediction of PaO2 from SpO2 values in critically ill invasively ventilated patients: rationale and protocol for a patient–level analysis of ERICC, LUNG SAFE, PRoVENT and PRoVENT–iMiC (PRoPERLy II)
Critical Care Science. 2025;37:e20250270
DOI 10.62675/2965-2774.20250270
- Simon Corrado Serafini ,
- David M. P. van Meenen ,
- Luigi Pisani ,
- Ary Serpa Neto ,
- Luciano César Pontes Azevedo ,
- Tai Pham ,
- Eya Sahraoui ,
- Giacomo Bellani ,
- John G. Laffey ,
- Marcus J. Schultz ,
- Guido Mazzinari
Views228ABSTRACT
Introduction:
In patients with acute respiratory distress syndrome (ARDS), mortality risk is typically assessed using the arterial partial pressure of oxygen (PaO2) divided by the fraction of inspired oxygen (FiO2), known as the PaO2/FiO2 ratio. Recently, the SpO2/FiO2 ratio, which uses peripheral oxygen saturation (SpO2) instead of PaO2, has been suggested as a reasonable alternative when there is little access to arterial blood gas analyses. Additionally, equations that predict PaO2 from SpO2 values could offer another viable method for assessment.
Aim:
To evaluate the accuracy of methods for predicting PaO2 from SpO2 values and compare risk stratification based on measured versus predicted PaO2/FiO2 ratios using a large database that harmonizes the individual data of patients included in four observational studies.
Methods and analysis:
The individual data from four observational studies (‘Epidemiology of Respiratory Insufficiency in Critical Care study’ [ERICC], ‘Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure’ [LUNG SAFE], ‘PRactice of VENTilation in critically ill patients without ARDS’ [PRoVENT], and ‘PRactice of VENTilation in critically ill patients in Middle–income Countries’ [PRoVENT–iMiC]) were harmonized and pooled into a database named ‘PRoPERLy II’. The primary endpoint of this planned analysis will be the accuracy of currently available methods to predict PaO2 from SpO2 values. The secondary endpoint will be the accuracy of classification based on SpO2/FiO2 ratio and the predicted PaO2/FiO2 ratio.
Dissemination:
Our planned analysis addresses a clinically important research question by comparing different equations for predicting PaO2 from SpO2 values.
Keywords:critical carecritical illnessOxygenOxygen saturationPartial pressureRespiration,artificialRespiratory distress syndromeRespiratory insufficiencyRisk assessmentSee moreViews228
Abstract
Case ReportPrediction of PaO2 from SpO2 values in critically ill invasively ventilated patients: rationale and protocol for a patient–level analysis of ERICC, LUNG SAFE, PRoVENT and PRoVENT–iMiC (PRoPERLy II)
Critical Care Science. 2025;37:e20250270
DOI 10.62675/2965-2774.20250270
- Simon Corrado Serafini ,
- David M. P. van Meenen ,
- Luigi Pisani ,
- Ary Serpa Neto ,
- Luciano César Pontes Azevedo ,
- Tai Pham ,
- Eya Sahraoui ,
- Giacomo Bellani ,
- John G. Laffey ,
- Marcus J. Schultz ,
- Guido Mazzinari
Views228ABSTRACT
Introduction:
In patients with acute respiratory distress syndrome (ARDS), mortality risk is typically assessed using the arterial partial pressure of oxygen (PaO2) divided by the fraction of inspired oxygen (FiO2), known as the PaO2/FiO2 ratio. Recently, the SpO2/FiO2 ratio, which uses peripheral oxygen saturation (SpO2) instead of PaO2, has been suggested as a reasonable alternative when there is little access to arterial blood gas analyses. Additionally, equations that predict PaO2 from SpO2 values could offer another viable method for assessment.
Aim:
To evaluate the accuracy of methods for predicting PaO2 from SpO2 values and compare risk stratification based on measured versus predicted PaO2/FiO2 ratios using a large database that harmonizes the individual data of patients included in four observational studies.
Methods and analysis:
The individual data from four observational studies (‘Epidemiology of Respiratory Insufficiency in Critical Care study’ [ERICC], ‘Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure’ [LUNG SAFE], ‘PRactice of VENTilation in critically ill patients without ARDS’ [PRoVENT], and ‘PRactice of VENTilation in critically ill patients in Middle–income Countries’ [PRoVENT–iMiC]) were harmonized and pooled into a database named ‘PRoPERLy II’. The primary endpoint of this planned analysis will be the accuracy of currently available methods to predict PaO2 from SpO2 values. The secondary endpoint will be the accuracy of classification based on SpO2/FiO2 ratio and the predicted PaO2/FiO2 ratio.
Dissemination:
Our planned analysis addresses a clinically important research question by comparing different equations for predicting PaO2 from SpO2 values.
Keywords:critical carecritical illnessOxygenOxygen saturationPartial pressureRespiration,artificialRespiratory distress syndromeRespiratory insufficiencyRisk assessmentSee more
- Simon Corrado Serafini
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Original Article08-08-2022
Can central-venous oxygen saturation be estimated from tissue oxygen saturation during a venous occlusion test?
Revista Brasileira de Terapia Intensiva. 2022;34(2):255-261
Abstract
Original ArticleCan central-venous oxygen saturation be estimated from tissue oxygen saturation during a venous occlusion test?
Revista Brasileira de Terapia Intensiva. 2022;34(2):255-261
DOI 10.5935/0103-507X.20220023-en
Views54See moreABSTRACT
Objective:
To test whether tissue oxygen saturation (StO2) after a venous occlusion test estimates central venous oxygen saturation (ScvO2).
Methods:
Observational study in intensive care unit patients. Tissue oxygen saturation was monitored (InSpectra Tissue Spectrometer Model 650, Hutchinson Technology Inc., MN, USA) with a multiprobe (15/25mm) in the thenar position. A venous occlusion test in volunteers was applied in the upper arm to test the tolerability and pattern of StO2 changes during the venous occlusion test. A sphygmomanometer cuff was inflated to a pressure 30mmHg above diastolic pressure until StO2 reached a plateau and deflated to 0mmHg. Tissue oxygen saturation parameters were divided into resting StO2 (r-StO2) and minimal StO2 (m-StO2) at the end of the venous occlusion test. In patients, the cuff was inflated to a pressure 30mmHg above diastolic pressure for 5 min (volunteers’ time derived) or until a StO2 plateau was reached. Tissue oxygen saturation parameters were divided into r-StO2, m-StO2, and the mean time that StO2 reached ScvO2. The StO2 value at the mean time was compared to ScvO2.
Results:
All 9 volunteers tolerated the venous occlusion test. The time for tolerability or the StO2 plateau was 7 ± 1 minutes. We studied 22 patients. The mean time for StO2 equalized ScvO2 was 100 sec and 95 sec (15/25mm probes). The StO2 value at 100 sec ([100-StO2] 15mm: 74 ± 7%; 25mm: 74 ± 6%) was then compared with ScvO2 (75 ± 6%). The StO2 value at 100 sec correlated with ScvO2 (15 mm: R2 = 0.63, 25mm: R2 = 0.67, p < 0.01) without discrepancy (Bland Altman).
Conclusion:
Central venous oxygen saturation can be estimated from StO2 during a venous occlusion test.
Views54Abstract
Original ArticleCan central-venous oxygen saturation be estimated from tissue oxygen saturation during a venous occlusion test?
Revista Brasileira de Terapia Intensiva. 2022;34(2):255-261
DOI 10.5935/0103-507X.20220023-en
Views54See moreABSTRACT
Objective:
To test whether tissue oxygen saturation (StO2) after a venous occlusion test estimates central venous oxygen saturation (ScvO2).
Methods:
Observational study in intensive care unit patients. Tissue oxygen saturation was monitored (InSpectra Tissue Spectrometer Model 650, Hutchinson Technology Inc., MN, USA) with a multiprobe (15/25mm) in the thenar position. A venous occlusion test in volunteers was applied in the upper arm to test the tolerability and pattern of StO2 changes during the venous occlusion test. A sphygmomanometer cuff was inflated to a pressure 30mmHg above diastolic pressure until StO2 reached a plateau and deflated to 0mmHg. Tissue oxygen saturation parameters were divided into resting StO2 (r-StO2) and minimal StO2 (m-StO2) at the end of the venous occlusion test. In patients, the cuff was inflated to a pressure 30mmHg above diastolic pressure for 5 min (volunteers’ time derived) or until a StO2 plateau was reached. Tissue oxygen saturation parameters were divided into r-StO2, m-StO2, and the mean time that StO2 reached ScvO2. The StO2 value at the mean time was compared to ScvO2.
Results:
All 9 volunteers tolerated the venous occlusion test. The time for tolerability or the StO2 plateau was 7 ± 1 minutes. We studied 22 patients. The mean time for StO2 equalized ScvO2 was 100 sec and 95 sec (15/25mm probes). The StO2 value at 100 sec ([100-StO2] 15mm: 74 ± 7%; 25mm: 74 ± 6%) was then compared with ScvO2 (75 ± 6%). The StO2 value at 100 sec correlated with ScvO2 (15 mm: R2 = 0.63, 25mm: R2 = 0.67, p < 0.01) without discrepancy (Bland Altman).
Conclusion:
Central venous oxygen saturation can be estimated from StO2 during a venous occlusion test.
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Review Article06-06-2022
Rationale and limitations of the SpO2/FiO2 as a possible substitute for PaO2/FiO2 in different preclinical and clinical scenarios
- Eduardo Butturini de Carvalho ,
- Thiago Ravache Sobreira Leite ,
- Raquel Ferreira de Magalhães Sacramento ,
- Paulo Roberto Loureiro do Nascimento ,
- Cynthia dos Santos Samary , [ ... ],
- Pedro Leme Silva
Abstract
Review ArticleRationale and limitations of the SpO2/FiO2 as a possible substitute for PaO2/FiO2 in different preclinical and clinical scenarios
Revista Brasileira de Terapia Intensiva. 2022;34(1):185-196
DOI 10.5935/0103-507X.20220013-en
- Eduardo Butturini de Carvalho ,
- Thiago Ravache Sobreira Leite ,
- Raquel Ferreira de Magalhães Sacramento ,
- Paulo Roberto Loureiro do Nascimento ,
- Cynthia dos Santos Samary ,
- Patrícia Rieken Macedo Rocco ,
- Pedro Leme Silva
Views130ABSTRACT
Although the PaO 2/FiO 2 derived from arterial blood gas analysis remains the gold standard for the diagnosis of acute respiratory failure, the SpO2/FiO2 has been investigated as a potential substitute. The current narrative review presents the state of the preclinical and clinical literature on the SpO2/FiO2 as a possible substitute for PaO2/FiO2 and for use as a diagnostic and prognostic marker; provides an overview of pulse oximetry and its limitations, and assesses the utility of SpO2/ FiO2 as a surrogate for PaO2/FiO2 in COVID-19 patients. Overall, 49 studies comparing SpO2/FiO2 and PaO2/FiO2 were found according to a minimal search strategy. Most were conducted on neonates, some were conducted on adults with acute respiratory distress syndrome, and a few were conducted in other clinical scenarios (including a very few on COVID-19 patients). There is some evidence that the SpO2/ FiO2 criteria can be a surrogate for PaO2/FiO2 in different clinical scenarios. This is reinforced by the fact that unnecessary invasive procedures should be avoided in patients with acute respiratory failure. It is undeniable that pulse oximeters are becoming increasingly widespread and can provide costless monitoring. Hence, replacing PaO2/FiO2 with SpO2/FiO2may allow resourcelimited facilities to objectively diagnose acute respiratory failure.
Keywords:Adultblood gas analysisCOVID-19InfantInfant, newbornOximetryOxygenOxygen saturationprognosisRespiratory distress syndromeRespiratory insufficiencySARS-CoV-2See moreViews130Abstract
Review ArticleRationale and limitations of the SpO2/FiO2 as a possible substitute for PaO2/FiO2 in different preclinical and clinical scenarios
Revista Brasileira de Terapia Intensiva. 2022;34(1):185-196
DOI 10.5935/0103-507X.20220013-en
- Eduardo Butturini de Carvalho ,
- Thiago Ravache Sobreira Leite ,
- Raquel Ferreira de Magalhães Sacramento ,
- Paulo Roberto Loureiro do Nascimento ,
- Cynthia dos Santos Samary ,
- Patrícia Rieken Macedo Rocco ,
- Pedro Leme Silva
Views130ABSTRACT
Although the PaO 2/FiO 2 derived from arterial blood gas analysis remains the gold standard for the diagnosis of acute respiratory failure, the SpO2/FiO2 has been investigated as a potential substitute. The current narrative review presents the state of the preclinical and clinical literature on the SpO2/FiO2 as a possible substitute for PaO2/FiO2 and for use as a diagnostic and prognostic marker; provides an overview of pulse oximetry and its limitations, and assesses the utility of SpO2/ FiO2 as a surrogate for PaO2/FiO2 in COVID-19 patients. Overall, 49 studies comparing SpO2/FiO2 and PaO2/FiO2 were found according to a minimal search strategy. Most were conducted on neonates, some were conducted on adults with acute respiratory distress syndrome, and a few were conducted in other clinical scenarios (including a very few on COVID-19 patients). There is some evidence that the SpO2/ FiO2 criteria can be a surrogate for PaO2/FiO2 in different clinical scenarios. This is reinforced by the fact that unnecessary invasive procedures should be avoided in patients with acute respiratory failure. It is undeniable that pulse oximeters are becoming increasingly widespread and can provide costless monitoring. Hence, replacing PaO2/FiO2 with SpO2/FiO2may allow resourcelimited facilities to objectively diagnose acute respiratory failure.
Keywords:Adultblood gas analysisCOVID-19InfantInfant, newbornOximetryOxygenOxygen saturationprognosisRespiratory distress syndromeRespiratory insufficiencySARS-CoV-2See more
- Eduardo Butturini de Carvalho
Oxygen saturation Archives - Critical Care Science (CCS)
