Carbon dioxide Archives - Critical Care Science (CCS)

  • ORIGINAL ARTICLE

    Factors associated with carbon dioxide transfer in an experimental model of severe acute kidney injury and hypoventilation during high bicarbonate continuous renal replacement therapy and oxygenation membrane support

    Critical Care Science. 06-19-2024;36:e20240005en

    Abstract

    ORIGINAL ARTICLE

    Factors associated with carbon dioxide transfer in an experimental model of severe acute kidney injury and hypoventilation during high bicarbonate continuous renal replacement therapy and oxygenation membrane support

    Critical Care Science. 06-19-2024;36:e20240005en

    DOI 10.62675/2965-2774.20240005-en

    Views33

    ABSTRACT

    Objective

    To investigate the factors influencing carbon dioxide transfer in a system that integrates an oxygenation membrane in series with high-bicarbonate continuous veno-venous hemodialysis in hypercapnic animals.

    Methods

    In an experimental setting, we induced severe acute kidney injury and hypercapnia in five female Landrace pigs. Subsequently, we initiated high (40mEq/L) bicarbonate continuous veno-venous hemodialysis with an oxygenation membrane in series to maintain a pH above 7.25. At intervals of 1 hour, 6 hours, and 12 hours following the initiation of continuous veno-venous hemodialysis, we performed standardized sweep gas flow titration to quantify carbon dioxide transfer. We evaluated factors associated with carbon dioxide transfer through the membrane lung with a mixed linear model.

    Results

    A total of 20 sweep gas flow titration procedures were conducted, yielding 84 measurements of carbon dioxide transfer. Multivariate analysis revealed associations among the following (coefficients ± standard errors): core temperature (+7.8 ± 1.6 °C, p < 0.001), premembrane partial pressure of carbon dioxide (+0.2 ± 0.1/mmHg, p < 0.001), hemoglobin level (+3.5 ± 0.6/g/dL, p < 0.001), sweep gas flow (+6.2 ± 0.2/L/minute, p < 0.001), and arterial oxygen saturation (-0.5 ± 0.2%, p = 0.019). Among these variables, and within the physiological ranges evaluated, sweep gas flow was the primary modifiable factor influencing the efficacy of low-blood-flow carbon dioxide removal.

    Conclusion

    Sweep gas flow is the main carbon dioxide removal-related variable during continuous veno-venous hemodialysis with a high bicarbonate level coupled with an oxygenator. Other carbon dioxide transfer modulating variables included the hemoglobin level, arterial oxygen saturation, partial pressure of carbon dioxide and core temperature. These results should be interpreted as exploratory to inform other well-designed experimental or clinical studies.

    See more
    Factors associated with carbon dioxide transfer in an experimental model of severe acute kidney injury and hypoventilation during high bicarbonate continuous renal replacement therapy and oxygenation membrane support
  • Review Article

    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

    Revista Brasileira de Terapia Intensiva. 08-08-2022;34(2):279-286

    Abstract

    Review Article

    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

    Revista Brasileira de Terapia Intensiva. 08-08-2022;34(2):279-286

    DOI 10.5935/0103-507X.20220026-en

    Views23

    ABSTRACT

    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.

    See more
    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
  • Review Article

    Central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio as an indicator of tissue oxygenation: a narrative review

    Revista Brasileira de Terapia Intensiva. 05-08-2020;32(1):115-122

    Abstract

    Review Article

    Central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio as an indicator of tissue oxygenation: a narrative review

    Revista Brasileira de Terapia Intensiva. 05-08-2020;32(1):115-122

    DOI 10.5935/0103-507X.20200017

    Views30

    ABSTRACT

    The central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio (Pcv-aCO2/Ca-cvO2) has been proposed as a surrogate for respiratory quotient and an indicator of tissue oxygenation. Some small observational studies have found that a Pcv-aCO2/Ca-cvO2 > 1.4 was associated with hyperlactatemia, oxygen supply dependency, and increased mortality. Moreover, Pcv-aCO2/Ca-cvO2 has been incorporated into algorithms for tissue oxygenation evaluation and resuscitation. However, the evidence for these recommendations is quite limited and of low quality. The goal of this narrative review was to analyze the methodological bases, the pathophysiologic foundations, and the experimental and clinical evidence supporting the use of Pcv-aCO2/Ca-cvO2 as a surrogate for respiratory quotient. Physiologically, the increase in respiratory quotient secondary to critical reductions in oxygen transport is a life-threatening and dramatic event. Nevertheless, this event is easily noticeable and probably does not require further monitoring. Since the beginning of anaerobic metabolism is indicated by the sudden increase in respiratory quotient and the normal range of respiratory quotient is wide, the use of a defined cutoff of 1.4 for Pcv-aCO2/Ca-cvO2 is meaningless. Experimental studies have shown that Pcv-aCO2/Ca-cvO2 is more dependent on factors that modify the dissociation of carbon dioxide from hemoglobin than on respiratory quotient and that respiratory quotient and Pcv-aCO2/Ca-cvO2 may have distinct behaviors. Studies performed in critically ill patients have shown controversial results regarding the ability of Pcv-aCO2/Ca-cvO2 to predict outcome, hyperlactatemia, microvascular abnormalities, and oxygen supply dependency. A randomized controlled trial also showed that Pcv-aCO2/Ca-cvO2 is useless as a goal of resuscitation. Pcv-aCO2/Ca-cvO2 should be carefully interpreted in critically ill patients.

    See more
    Central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio as an indicator of tissue oxygenation: a narrative review

Search

Search in:

Article type
article-commentary
brief-report
case-report
correction
editorial
letter
other
rapid-communication
reply
research-article
review-article
Section
Article
Articles
Artigo de Revisão
Artigo de Revisão - Pediatria
Artigo de Revisão de Pediatria
Artigo Original
Artigo Original - Enfermagem
Artigo Original - Neonatologia
Artigo Original de Pediatria
Artigo Original Destaque
Artigos de Revisão
Artigos Originais
AUTHOR’S RESPONSE
AUTHORS’ RESPONSE
BRIEF COMMUNICATION
Carta ao Editor
CARTAS AO EDITOR
Case Report
Case Report
Case Reports
CLINICAL REPORT
Comentário
Comentários
COMMENTARIES
COMMENTARY
Consenso Brasileiro de Monitorização e Suporte Hemodinâmico
Correspondence
Editorial
EDITORIALS
Erratum
Erratum
Guidelines and Consensus
III Consenso Brasileiro de Ventilação Mecância
Informação Clínica
LETTER TO THE EDITOR
Letter to the Editor
Letters to the Editor
NARRATIVE REVIEW
ORIGINAL ARTICLE
ORIGINAL ARTICLE
Original Article - Basic Research
Original Article - Neonatologia
Original Article - Pediatria
Original Articles
Original Articles - Basic Research
Original Articles - Clinical Research
Relato de Caso
Relatos de Caso
Relatos de Casos
Research Letter
REVIEW
Review Article
Review Articles
Série: Medicina baseada em evidências e terapia intensiva
Série: Terminalidade em UTI
SPECIAL ARTICLE
Special Article
Special Articles
Terminalidade em UTI pediátrica
Viewpoint
Year / Volume
2025; v.37
2024; v.36
2023; v.35
2022; v.34
2021; v.33
2020; v.32
2019; v.31
2018; v.30
2017; v.29
2016; v.28
2015; v.27
2014; v.26
2013; v.25
2012; v.24
2011; v.23
2010; v.22
2009; v.21
2008; v.20
2007; v.19
2006; v.18
ISSUE