-
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
Views203ABSTRACT
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 moreViews203
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
Views203ABSTRACT
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
-
Original Article10-09-2024
Comparison of the effectiveness of awake-prone positioning and high-flow nasal oxygen in patients with COVID-19-related acute respiratory failure between different waves
- Mariano Esperatti ,
- Matías Olmos ,
- Marina Busico ,
- Adrian Gallardo ,
- Alejandra Vitali , [ ... ],
Abstract
Original ArticleComparison of the effectiveness of awake-prone positioning and high-flow nasal oxygen in patients with COVID-19-related acute respiratory failure between different waves
Critical Care Science. 2024;36:e20240065en
DOI 10.62675/2965-2774.20240065-en
- Mariano Esperatti ,
- Matías Olmos ,
- Marina Busico ,
- Adrian Gallardo ,
- Alejandra Vitali ,
- Jorgelina Quintana ,
- Hiromi Kakisu ,
- Bruno Leonel Ferreyro ,
- Nora Angélica Fuentes ,
Views66ABSTRACT
Objective:
To compare the effectiveness of the awake-prone position on relevant clinical outcomes in patients with COVID-19-related acute respiratory failure requiring high-flow nasal oxygen between different waves in Argentina.
Methods:
This multicenter, prospective cohort study included adult patients with COVID-19-related acute respiratory failure requiring high-flow nasal oxygen. The main exposure position was the awake-prone position (≥ 6 hours/day) compared to the non-prone position. The primary outcome was endotracheal intubation, and the secondary outcome was in-hospital mortality. The inverse probability weighting–propensity score was used to adjust the conditional probability of treatment assignment. We then adjusted for contextual variables that varied over time and compared the effectiveness between the first and second waves.
Results:
A total of 728 patients were included: 360 during the first wave and 368 during the second wave, of whom 195 (54%) and 227 (62%) remained awake-prone for a median (p25 - 75) of 12 (10 - 16) and 14 (8 - 17) hours/day, respectively (Awake-Prone Position Group). The ORs (95%CIs) for endotracheal intubation in the Awake-Prone Position Group were 0.25 (0.13 - 0.46) and 0.19 (0.09 - 0.31) for the first and second waves, respectively (p = 0.41 for comparison between waves). The ORs for in-hospital mortality in the awake-prone position were 0.35 (0.17 - 0.65) and 0.22 (0.12 - 0.43), respectively (p = 0.44 for comparison between waves).
Conclusion:
The awake-prone position was associated with a reduction in the risk of endotracheal intubation and in-hospital mortality. These effects were independent of the context in which the intervention was applied, and no differences were observed between the different waves.
Keywords:Coronavirus infectionsCOVID-19Hospital mortalityIntubation, endotrachealOxygenprone positionRespiratory insufficiencySARS-CoV-2See moreViews66Abstract
Original ArticleComparison of the effectiveness of awake-prone positioning and high-flow nasal oxygen in patients with COVID-19-related acute respiratory failure between different waves
Critical Care Science. 2024;36:e20240065en
DOI 10.62675/2965-2774.20240065-en
- Mariano Esperatti ,
- Matías Olmos ,
- Marina Busico ,
- Adrian Gallardo ,
- Alejandra Vitali ,
- Jorgelina Quintana ,
- Hiromi Kakisu ,
- Bruno Leonel Ferreyro ,
- Nora Angélica Fuentes ,
Views66ABSTRACT
Objective:
To compare the effectiveness of the awake-prone position on relevant clinical outcomes in patients with COVID-19-related acute respiratory failure requiring high-flow nasal oxygen between different waves in Argentina.
Methods:
This multicenter, prospective cohort study included adult patients with COVID-19-related acute respiratory failure requiring high-flow nasal oxygen. The main exposure position was the awake-prone position (≥ 6 hours/day) compared to the non-prone position. The primary outcome was endotracheal intubation, and the secondary outcome was in-hospital mortality. The inverse probability weighting–propensity score was used to adjust the conditional probability of treatment assignment. We then adjusted for contextual variables that varied over time and compared the effectiveness between the first and second waves.
Results:
A total of 728 patients were included: 360 during the first wave and 368 during the second wave, of whom 195 (54%) and 227 (62%) remained awake-prone for a median (p25 - 75) of 12 (10 - 16) and 14 (8 - 17) hours/day, respectively (Awake-Prone Position Group). The ORs (95%CIs) for endotracheal intubation in the Awake-Prone Position Group were 0.25 (0.13 - 0.46) and 0.19 (0.09 - 0.31) for the first and second waves, respectively (p = 0.41 for comparison between waves). The ORs for in-hospital mortality in the awake-prone position were 0.35 (0.17 - 0.65) and 0.22 (0.12 - 0.43), respectively (p = 0.44 for comparison between waves).
Conclusion:
The awake-prone position was associated with a reduction in the risk of endotracheal intubation and in-hospital mortality. These effects were independent of the context in which the intervention was applied, and no differences were observed between the different waves.
Keywords:Coronavirus infectionsCOVID-19Hospital mortalityIntubation, endotrachealOxygenprone positionRespiratory insufficiencySARS-CoV-2See more
- Mariano Esperatti
-
Case Report07-24-2024
Adherence to low tidal volume in the transition to spontaneous ventilation in patients with acute respiratory failure in intensive care units in Latin America (SPIRAL): a study protocol
- Fabia Diniz-Silva ,
- Bruno Valle Pinheiro ,
- Luis Felipe Reyes ,
- Alexandre Biasi Cavalcanti ,
- Belinda Figueredo , [ ... ],
Abstract
Case ReportAdherence to low tidal volume in the transition to spontaneous ventilation in patients with acute respiratory failure in intensive care units in Latin America (SPIRAL): a study protocol
Critical Care Science. 2024;36:e20240044en
DOI 10.62675/2965-2774.20240044-en
- Fabia Diniz-Silva ,
- Bruno Valle Pinheiro ,
- Luis Felipe Reyes ,
- Alexandre Biasi Cavalcanti ,
- Belinda Figueredo ,
- Fernando Rios ,
- Flávia Ribeiro Machado ,
- Gabriel Preda ,
- Guillermo Bugedo ,
- Israel Silva Maia ,
- Leda Tomiko Yamada da Silveira ,
- Luis Herrera ,
- Manuel Jibaja ,
- Miguel Ibarra-Estrada ,
- Mino Cestari ,
- Nicolás Nin ,
- Rollin Roldan ,
- Tiago Mendonça dos Santos ,
- Viviane Cordeiro Veiga ,
- Alejandro Bruhn ,
- Juliana Carvalho Ferreira ,
Views139ABSTRACT
Objective:
Patients with acute respiratory failure often require mechanical ventilation to reduce the work of breathing and improve gas exchange; however, this may exacerbate lung injury. Protective ventilation strategies, characterized by low tidal volumes (≤ 8mL/kg of predicted body weight) and limited plateau pressure below 30cmH2O, have shown improved outcomes in patients with acute respiratory distress syndrome. However, in the transition to spontaneous ventilation, it can be challenging to maintain tidal volume within protective levels, and it is unclear whether low tidal volumes during spontaneous ventilation impact patient outcomes. We developed a study protocol to estimate the prevalence of low tidal volume ventilation in the first 24 hours of spontaneous ventilation in patients with hypoxemic acute respiratory failure and its association with ventilator-free days and survival.
Methods:
We designed a multicenter, multinational, cohort study with a 28-day follow-up that will include patients with acute respiratory failure, defined as a partial oxygen pressure/fraction of inspired oxygen ratio < 300mmHg, in transition to spontaneous ventilation in intensive care units in Latin America.
Results:
We plan to include 422 patients in ten countries. The primary outcomes are the prevalence of low tidal volume in the first 24 hours of spontaneous ventilation and ventilator-free days on day 28. The secondary outcomes are intensive care unit and hospital mortality, incidence of asynchrony and return to controlled ventilation and sedation.
Conclusion:
In this study, we will assess the prevalence of low tidal volume during spontaneous ventilation and its association with clinical outcomes, which can inform clinical practice and future clinical trials.
Keywords:Hospital mortalityIncidenceintensive care unitsOxygenprevalenceRespiration, artificialRespiratory insufficiencyTidal VolumeSee moreViews139Abstract
Case ReportAdherence to low tidal volume in the transition to spontaneous ventilation in patients with acute respiratory failure in intensive care units in Latin America (SPIRAL): a study protocol
Critical Care Science. 2024;36:e20240044en
DOI 10.62675/2965-2774.20240044-en
- Fabia Diniz-Silva ,
- Bruno Valle Pinheiro ,
- Luis Felipe Reyes ,
- Alexandre Biasi Cavalcanti ,
- Belinda Figueredo ,
- Fernando Rios ,
- Flávia Ribeiro Machado ,
- Gabriel Preda ,
- Guillermo Bugedo ,
- Israel Silva Maia ,
- Leda Tomiko Yamada da Silveira ,
- Luis Herrera ,
- Manuel Jibaja ,
- Miguel Ibarra-Estrada ,
- Mino Cestari ,
- Nicolás Nin ,
- Rollin Roldan ,
- Tiago Mendonça dos Santos ,
- Viviane Cordeiro Veiga ,
- Alejandro Bruhn ,
- Juliana Carvalho Ferreira ,
Views139ABSTRACT
Objective:
Patients with acute respiratory failure often require mechanical ventilation to reduce the work of breathing and improve gas exchange; however, this may exacerbate lung injury. Protective ventilation strategies, characterized by low tidal volumes (≤ 8mL/kg of predicted body weight) and limited plateau pressure below 30cmH2O, have shown improved outcomes in patients with acute respiratory distress syndrome. However, in the transition to spontaneous ventilation, it can be challenging to maintain tidal volume within protective levels, and it is unclear whether low tidal volumes during spontaneous ventilation impact patient outcomes. We developed a study protocol to estimate the prevalence of low tidal volume ventilation in the first 24 hours of spontaneous ventilation in patients with hypoxemic acute respiratory failure and its association with ventilator-free days and survival.
Methods:
We designed a multicenter, multinational, cohort study with a 28-day follow-up that will include patients with acute respiratory failure, defined as a partial oxygen pressure/fraction of inspired oxygen ratio < 300mmHg, in transition to spontaneous ventilation in intensive care units in Latin America.
Results:
We plan to include 422 patients in ten countries. The primary outcomes are the prevalence of low tidal volume in the first 24 hours of spontaneous ventilation and ventilator-free days on day 28. The secondary outcomes are intensive care unit and hospital mortality, incidence of asynchrony and return to controlled ventilation and sedation.
Conclusion:
In this study, we will assess the prevalence of low tidal volume during spontaneous ventilation and its association with clinical outcomes, which can inform clinical practice and future clinical trials.
Keywords:Hospital mortalityIncidenceintensive care unitsOxygenprevalenceRespiration, artificialRespiratory insufficiencyTidal VolumeSee more
- Fabia Diniz-Silva
-
Original Article06-14-2024
The respiratory oxygenation index for identifying the risk of orotracheal intubation in COVID-19 patients receiving high-flow nasal cannula oxygen
- Aline Braz Pereira ,
- Felipe Dal Pizzol ,
- Viviane Cordeiro Veiga ,
- Leandro Utino Taniguchi ,
- Aline Finoti Misquita , [ ... ],
- Glauco Adrieno Westphal
Abstract
Original ArticleThe respiratory oxygenation index for identifying the risk of orotracheal intubation in COVID-19 patients receiving high-flow nasal cannula oxygen
Critical Care Science. 2024;36:e20240203en
DOI 10.62675/2965-2774.20240203-en
- Aline Braz Pereira ,
- Felipe Dal Pizzol ,
- Viviane Cordeiro Veiga ,
- Leandro Utino Taniguchi ,
- Aline Finoti Misquita ,
- Gustavo Augusto Couto Carvalho ,
- Ligia Maria Coscrato Junqueira Silva ,
- Michelli Marcela Dadam ,
- Ruthy Perotto Fernandes ,
- Israel Silva Maia ,
- Cassio Luis Zandonai ,
- Alexandre Biasi Cavalcanti ,
- Marcelo Luz Pereira Romano ,
- Glauco Adrieno Westphal
Views122ABSTRACT
Objective:
To assess whether the respiratory oxygenation index (ROX index) measured after the start of high-flow nasal cannula oxygen therapy can help identify the need for intubation in patients with acute respiratory failure due to coronavirus disease 2019.
Methods:
This retrospective, observational, multicenter study was conducted at the intensive care units of six Brazilian hospitals from March to December 2020. The primary outcome was the need for intubation up to 7 days after starting the high-flow nasal cannula.
Results:
A total of 444 patients were included in the study, and 261 (58.7%) were subjected to intubation. An analysis of the area under the receiver operating characteristic curve (AUROC) showed that the ability to discriminate between successful and failed high-flow nasal cannula oxygen therapy within 7 days was greater for the ROX index measured at 24 hours (AUROC 0.80; 95%CI 0.76 - 0.84). The median interval between high-flow nasal cannula initiation and intubation was 24 hours (24 - 72), and the most accurate predictor of intubation obtained before 24 hours was the ROX index measured at 12 hours (AUROC 0.75; 95%CI 0.70 - 0.79). Kaplan-Meier curves revealed a greater probability of intubation within 7 days in patients with a ROX index ≤ 5.54 at 12 hours (hazard ratio 3.07; 95%CI 2.24 - 4.20) and ≤ 5.96 at 24 hours (hazard ratio 5.15; 95%CI 3.65 - 7.27).
Conclusion:
The ROX index can aid in the early identification of patients with acute respiratory failure due to COVID-19 who will progress to the failure of high-flow nasal cannula supportive therapy and the need for intubation.
Keywords:CannulaCoronavirus infectionsCOVID-19intubationOxygenRespiratory insufficiencyRespiratory rateSee moreViews122Abstract
Original ArticleThe respiratory oxygenation index for identifying the risk of orotracheal intubation in COVID-19 patients receiving high-flow nasal cannula oxygen
Critical Care Science. 2024;36:e20240203en
DOI 10.62675/2965-2774.20240203-en
- Aline Braz Pereira ,
- Felipe Dal Pizzol ,
- Viviane Cordeiro Veiga ,
- Leandro Utino Taniguchi ,
- Aline Finoti Misquita ,
- Gustavo Augusto Couto Carvalho ,
- Ligia Maria Coscrato Junqueira Silva ,
- Michelli Marcela Dadam ,
- Ruthy Perotto Fernandes ,
- Israel Silva Maia ,
- Cassio Luis Zandonai ,
- Alexandre Biasi Cavalcanti ,
- Marcelo Luz Pereira Romano ,
- Glauco Adrieno Westphal
Views122ABSTRACT
Objective:
To assess whether the respiratory oxygenation index (ROX index) measured after the start of high-flow nasal cannula oxygen therapy can help identify the need for intubation in patients with acute respiratory failure due to coronavirus disease 2019.
Methods:
This retrospective, observational, multicenter study was conducted at the intensive care units of six Brazilian hospitals from March to December 2020. The primary outcome was the need for intubation up to 7 days after starting the high-flow nasal cannula.
Results:
A total of 444 patients were included in the study, and 261 (58.7%) were subjected to intubation. An analysis of the area under the receiver operating characteristic curve (AUROC) showed that the ability to discriminate between successful and failed high-flow nasal cannula oxygen therapy within 7 days was greater for the ROX index measured at 24 hours (AUROC 0.80; 95%CI 0.76 - 0.84). The median interval between high-flow nasal cannula initiation and intubation was 24 hours (24 - 72), and the most accurate predictor of intubation obtained before 24 hours was the ROX index measured at 12 hours (AUROC 0.75; 95%CI 0.70 - 0.79). Kaplan-Meier curves revealed a greater probability of intubation within 7 days in patients with a ROX index ≤ 5.54 at 12 hours (hazard ratio 3.07; 95%CI 2.24 - 4.20) and ≤ 5.96 at 24 hours (hazard ratio 5.15; 95%CI 3.65 - 7.27).
Conclusion:
The ROX index can aid in the early identification of patients with acute respiratory failure due to COVID-19 who will progress to the failure of high-flow nasal cannula supportive therapy and the need for intubation.
Keywords:CannulaCoronavirus infectionsCOVID-19intubationOxygenRespiratory insufficiencyRespiratory rateSee more
- Aline Braz Pereira
-
Original Article11-04-2022
Robust, maintainable, emergency invasive mechanical ventilator
- Paulo J. R. Fonte ,
- Alberto Martinho ,
- Américo Pereira,
- Andreia Gomes ,
- Ângela Neves , [ ... ],
- Telmo G. Santos
Abstract
Original ArticleRobust, maintainable, emergency invasive mechanical ventilator
Revista Brasileira de Terapia Intensiva. 2022;34(3):351-359
DOI 10.5935/0103-507X.20220383-en
- Paulo J. R. Fonte ,
- Alberto Martinho ,
- Américo Pereira,
- Andreia Gomes ,
- Ângela Neves ,
- Antero Abrunhosa ,
- António Bugalho ,
- António Gabriel-Santos ,
- António Grilo ,
- Carlos Carmo,
- Elsa Maltez ,
- João Agostinho do Nascimento ,
- João Goes ,
- João Martins ,
- João Pedro Oliveira ,
- Jorge Pimenta ,
- José Paulo Santos ,
- Luís C. Gil ,
- Luís Lopes ,
- Mário Pimenta ,
- Olga Moreira ,
- Orlando Cunha ,
- Pedro Pinheiro de Sousa,
- Pedro Póvoa ,
- Sandra Cavaco-Gonçalves ,
- Susana Barroso ,
- Telmo G. Santos
Views46ABSTRACT
Objective:
To develop a simple, robust, safe and efficient invasive mechanical ventilator that can be used in remote areas of the world or war zones where the practical utility of more sophisticated equipment is limited by considerations of maintainability, availability of parts, transportation and/or cost.
Methods:
The device implements the pressure-controlled continuous mandatory ventilation mode, complemented by a simple assist-control mode. Continuous positive airway pressure is also possible. The consumption of compressed gases is minimized by avoiding a continuous flow of oxygen or air. Respiratory rates and inspiration/expiration time ratios are electronically determined, and an apnea/power loss alarm is provided.
Results:
The pressure profiles were measured for a range of conditions and found to be adjustable within a ± 2.5cmH2O error margin and stable well within this range over a 41-hour period. Respiratory cycle timing parameters were precise within a few percentage points over the same period. The device was tested for durability for an equivalent period of four months. Chemical and biological tests failed to identify any contamination of the gas by volatile organic compounds or microorganisms. A ventilation test on a large animal, in comparison with a well established ventilator, showed that the animal could be adequately ventilated over a period of 60 minutes, without any noticeable negative aftereffects during the subsequent 24-hour period.
Conclusion:
This ventilator design may be viable, after further animal tests and formal approval by the competent authorities, for clinical application in the abovementioned atypical circumstances.
Keywords:AnimalsContinuous positive airway pressureGasesmechanicalOxygenPulmonary VentilationRespiratory rateventilatorsVolatile organic compoundsSee moreViews46Abstract
Original ArticleRobust, maintainable, emergency invasive mechanical ventilator
Revista Brasileira de Terapia Intensiva. 2022;34(3):351-359
DOI 10.5935/0103-507X.20220383-en
- Paulo J. R. Fonte ,
- Alberto Martinho ,
- Américo Pereira,
- Andreia Gomes ,
- Ângela Neves ,
- Antero Abrunhosa ,
- António Bugalho ,
- António Gabriel-Santos ,
- António Grilo ,
- Carlos Carmo,
- Elsa Maltez ,
- João Agostinho do Nascimento ,
- João Goes ,
- João Martins ,
- João Pedro Oliveira ,
- Jorge Pimenta ,
- José Paulo Santos ,
- Luís C. Gil ,
- Luís Lopes ,
- Mário Pimenta ,
- Olga Moreira ,
- Orlando Cunha ,
- Pedro Pinheiro de Sousa,
- Pedro Póvoa ,
- Sandra Cavaco-Gonçalves ,
- Susana Barroso ,
- Telmo G. Santos
Views46ABSTRACT
Objective:
To develop a simple, robust, safe and efficient invasive mechanical ventilator that can be used in remote areas of the world or war zones where the practical utility of more sophisticated equipment is limited by considerations of maintainability, availability of parts, transportation and/or cost.
Methods:
The device implements the pressure-controlled continuous mandatory ventilation mode, complemented by a simple assist-control mode. Continuous positive airway pressure is also possible. The consumption of compressed gases is minimized by avoiding a continuous flow of oxygen or air. Respiratory rates and inspiration/expiration time ratios are electronically determined, and an apnea/power loss alarm is provided.
Results:
The pressure profiles were measured for a range of conditions and found to be adjustable within a ± 2.5cmH2O error margin and stable well within this range over a 41-hour period. Respiratory cycle timing parameters were precise within a few percentage points over the same period. The device was tested for durability for an equivalent period of four months. Chemical and biological tests failed to identify any contamination of the gas by volatile organic compounds or microorganisms. A ventilation test on a large animal, in comparison with a well established ventilator, showed that the animal could be adequately ventilated over a period of 60 minutes, without any noticeable negative aftereffects during the subsequent 24-hour period.
Conclusion:
This ventilator design may be viable, after further animal tests and formal approval by the competent authorities, for clinical application in the abovementioned atypical circumstances.
Keywords:AnimalsContinuous positive airway pressureGasesmechanicalOxygenPulmonary VentilationRespiratory rateventilatorsVolatile organic compoundsSee more
- Paulo J. R. Fonte
-
Review Article08-08-2022
Comparison of central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio and lactate levels as predictors of mortality in critically ill patients: a systematic review and meta-analysis
- Arnaldo Dubin ,
- Cecilia Inés Loudet ,
- Francisco Javier Hurtado ,
- Mario Omar Pozo ,
- Daniel Comande , [ ... ],
- Ariel Bardach
Abstract
Review ArticleComparison of central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio and lactate levels as predictors of mortality in critically ill patients: a systematic review and meta-analysis
Revista Brasileira de Terapia Intensiva. 2022;34(2):279-286
DOI 10.5935/0103-507X.20220026-en
- Arnaldo Dubin ,
- Cecilia Inés Loudet ,
- Francisco Javier Hurtado ,
- Mario Omar Pozo ,
- Daniel Comande ,
- Luz Gibbons ,
- Federico Rodriguez Cairoli ,
- Ariel Bardach
Views49See moreABSTRACT
Objective:
The central venousarterial carbon dioxide pressure to arterial-central venous oxygen content ratio (Pcv-aCO2/Ca-cvO2) is frequently used as a surrogate for tissue oxygenation. We aimed to identify and synthesize literature and quality of evidence supporting Pcv-aCO2/Ca-cvO2 as a predictor of mortality in critically ill patients compared with lactate.
Methods:
We searched several databases for studies measuring Pcv-aCO2/Ca-cvO2 in critically ill patients. Independent investigators performed the article screening and data extraction. A random-effects metaanalysis was performed. Pooled standardized mean differences (SMD) were used to compare the prognostic ability of Pcv-aCO2/Ca-cvO2 and lactate.
Results:
We initially retrieved 172 studies; 17 were included for qualitative description, and 10 were included for quantitative synthesis. The mean Pcv-aCO2/Ca-cvO2 was higher in nonsurvivors than in survivors (pooled SMD = 0.75; 95%CI 0.34 - 1.17; I = 83%), as was the case with lactate levels (pooled SMD = 0.94; 95%CI 0.34 - 1.54; I = 92%). Both tests were statistically significant predictors of mortality, albeit with overlapping 95%CIs between them.
Conclusion:
Moderate-quality evidence showed little or no difference in the ability of Pcv-aCO2/Ca-cvO2, compared with lactate, to predict mortality. Nevertheless, our conclusions are limited by the considerable heterogeneity among the studies.
Views49Abstract
Review ArticleComparison of central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio and lactate levels as predictors of mortality in critically ill patients: a systematic review and meta-analysis
Revista Brasileira de Terapia Intensiva. 2022;34(2):279-286
DOI 10.5935/0103-507X.20220026-en
- Arnaldo Dubin ,
- Cecilia Inés Loudet ,
- Francisco Javier Hurtado ,
- Mario Omar Pozo ,
- Daniel Comande ,
- Luz Gibbons ,
- Federico Rodriguez Cairoli ,
- Ariel Bardach
Views49See moreABSTRACT
Objective:
The central venousarterial carbon dioxide pressure to arterial-central venous oxygen content ratio (Pcv-aCO2/Ca-cvO2) is frequently used as a surrogate for tissue oxygenation. We aimed to identify and synthesize literature and quality of evidence supporting Pcv-aCO2/Ca-cvO2 as a predictor of mortality in critically ill patients compared with lactate.
Methods:
We searched several databases for studies measuring Pcv-aCO2/Ca-cvO2 in critically ill patients. Independent investigators performed the article screening and data extraction. A random-effects metaanalysis was performed. Pooled standardized mean differences (SMD) were used to compare the prognostic ability of Pcv-aCO2/Ca-cvO2 and lactate.
Results:
We initially retrieved 172 studies; 17 were included for qualitative description, and 10 were included for quantitative synthesis. The mean Pcv-aCO2/Ca-cvO2 was higher in nonsurvivors than in survivors (pooled SMD = 0.75; 95%CI 0.34 - 1.17; I = 83%), as was the case with lactate levels (pooled SMD = 0.94; 95%CI 0.34 - 1.54; I = 92%). Both tests were statistically significant predictors of mortality, albeit with overlapping 95%CIs between them.
Conclusion:
Moderate-quality evidence showed little or no difference in the ability of Pcv-aCO2/Ca-cvO2, compared with lactate, to predict mortality. Nevertheless, our conclusions are limited by the considerable heterogeneity among the studies.
- Arnaldo Dubin
-
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
Views124ABSTRACT
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 moreViews124Abstract
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
Views124ABSTRACT
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
-
Review Article08-01-2013
Use of femoral vein catheters for the assessment of perfusion parameters
Revista Brasileira de Terapia Intensiva. 2013;25(2):168-174
Abstract
Review ArticleUse of femoral vein catheters for the assessment of perfusion parameters
Revista Brasileira de Terapia Intensiva. 2013;25(2):168-174
DOI 10.5935/0103-507X.20130029
Views44The use of central venous oxygen saturation (SvcO2) and arterial lactate in the diagnosis of severe tissue hypoperfusion is well established, and the optimization of these parameters is currently under investigation, particularly in patients with severe sepsis/septic shock. However, the only place for deep venous puncture or the first choice for puncture is often the femoral vein. Although venous saturation obtained from blood sampling from this catheter, instead of SvcO2, has already been used in the diagnosis of severe tissue hypoperfusion, little is known about the accuracy of the results. The venous lactate in place of arterial puncture has also been used to guide therapeutic decisions. We conducted this literature review to seek evidence on the correlation and concordance of parameters obtained by collecting femoral venous blood gases in relation to SvcO2 and arterial lactate. Few studies in the literature have evaluated the use of femoral venous oxygen saturation (SvfO2) or venous lactate. The results obtained thus far demonstrate no adequate agreement between SvfO2 and SvcO2, which limits the clinical use of SvfO2. However, the apparent strong correlation between arterial and peripheral and central venous lactate values suggests that venous lactate obtained from the femoral vein could eventually be used instead of arterial lactate, although there is insufficient evidence on which to base this procedure at this time.
Keywords:Catheterization, centralCentral venous pressureFemoral veinHemodynamicsOxygenPerfusionsepsisSee moreViews44Abstract
Review ArticleUse of femoral vein catheters for the assessment of perfusion parameters
Revista Brasileira de Terapia Intensiva. 2013;25(2):168-174
DOI 10.5935/0103-507X.20130029
Views44The use of central venous oxygen saturation (SvcO2) and arterial lactate in the diagnosis of severe tissue hypoperfusion is well established, and the optimization of these parameters is currently under investigation, particularly in patients with severe sepsis/septic shock. However, the only place for deep venous puncture or the first choice for puncture is often the femoral vein. Although venous saturation obtained from blood sampling from this catheter, instead of SvcO2, has already been used in the diagnosis of severe tissue hypoperfusion, little is known about the accuracy of the results. The venous lactate in place of arterial puncture has also been used to guide therapeutic decisions. We conducted this literature review to seek evidence on the correlation and concordance of parameters obtained by collecting femoral venous blood gases in relation to SvcO2 and arterial lactate. Few studies in the literature have evaluated the use of femoral venous oxygen saturation (SvfO2) or venous lactate. The results obtained thus far demonstrate no adequate agreement between SvfO2 and SvcO2, which limits the clinical use of SvfO2. However, the apparent strong correlation between arterial and peripheral and central venous lactate values suggests that venous lactate obtained from the femoral vein could eventually be used instead of arterial lactate, although there is insufficient evidence on which to base this procedure at this time.
Keywords:Catheterization, centralCentral venous pressureFemoral veinHemodynamicsOxygenPerfusionsepsisSee more
Oxygen Archives - Critical Care Science (CCS)
