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

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.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:32

Enthalten in:

Revista Brasileira de terapia intensiva - 32(2020), 1 vom: 08. März, Seite 115-122

Sprache:

Englisch

Weiterer Titel:

Proporção entre pressão venosa central menos arterial de dióxido de carbono e conteúdo arterial menos venoso central de oxigênio como indicador de oxigenação tissular: uma revisão narrativa

Beteiligte Personen:

Dubin, Arnaldo [VerfasserIn]
Pozo, Mario Omar [VerfasserIn]
Hurtado, Javier [VerfasserIn]

Links:

Volltext

Themen:

142M471B3J
Carbon Dioxide
Journal Article
Oxygen
Review
S88TT14065

Anmerkungen:

Date Completed 14.05.2021

Date Revised 14.05.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.5935/0103-507x.20200017

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM309849608