Lack of correlation between central venous minus arterial PCO to arterial minus central venous O content ratio and respiratory quotient in patients with septic shock: A prospective observational study.

Objective: Central venous-arterial PCO to arterial-central venous O content ratio (PCO/CO) is commonly used as a surrogate for respiratory quotient (RQ) and tissue oxygenation. Although PCO/CO might be associated with hyperlactatemia and outcome, neither the interchangeability with RQ nor the correlation with conclusive variables of anaerobic metabolism has never been demonstrated in septic shock. Our goal was to compare PCO/CO and RQ in patients with septic shock.

Venous Minus Arterial Carbon Dioxide Gradients in the Monitoring of Tissue Perfusion and Oxygenation: A Narrative Review.

According to Fick's principle, the total uptake of (or release of) a substance by tissues is the product of blood flow and the difference between the arterial and the venous concentration of the substance. Therefore, the mixed or central venous minus arterial CO content difference depends on cardiac output (CO). Assuming a linear relationship between CO content and partial pressure, central or mixed venous minus arterial PCO differences (PCO and PCO) are directly related to CO.

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.

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.

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.

Health inequities in the diagnosis and outcome of sepsis in Argentina: a prospective cohort study.

Background: Socioeconomic variables impact health outcomes but have rarely been evaluated in critical illness. Low- and middle-income countries bear the highest burden of sepsis and also have significant health inequities. In Argentina, public hospitals serve the poorest segment of the population, while private institutions serve patients with health coverage.

Effects of short-term hyperoxia on sytemic hemodynamics, oxygen transport, and microcirculation: An observational study in patients with septic shock and healthy volunteers.

Purpose: To characterize the microvascular effects of a brief period of hyperoxia, in patients with septic shock and in healthy volunteers.

Materials And Methods: In 20 patients with septic shock, we assessed systemic hemodynamics, sublingual microcirculation by SDF-videomicroscopy, and skin perfusion by capillary refill time (CRT), central-peripheral temperature (ΔT°), and perfusion index. Measurements were performed at baseline and after 5 min of inspired oxygen fraction of 1.

Poor agreement in the calculation of venoarterial PCO to arteriovenous O content difference ratio using central and mixed venous blood samples in septic patients.

Purpose: Central venous minus arterial PCO to arterial minus central venous O content difference ratio (PCO/CO) has been proposed as a clinical surrogate for respiratory quotient. Our goal was to assess its interchangeability with mixed venous minus arterial PCO to arterial minus mixed venous O content difference ratio (PCO/CO).

Materials And Methods: This is a subanalysis of a previously published study.

Predictive Validity of Sepsis-3 Definitions and Sepsis Outcomes in Critically Ill Patients: A Cohort Study in 49 ICUs in Argentina.

Objectives: The new Sepsis-3 definitions have been scarcely assessed in low- and middle-income countries; besides, regional information of sepsis outcomes is sparse. Our objective was to evaluate Sepsis-3 definition performance in Argentina.

Design: Cohort study of 3-month duration beginning on July 1, 2016.

Sublingual microcirculatory alterations in cirrhotic patients.

Objective: To assess sublingual microcirculation in cirrhotic patients and its relationship to spider angiomas, complications, and outcome.

Methods: Thirty-one cirrhotic patients were prospectively compared to 31 matched controls. Sublingual microcirculation was evaluated by videomicroscopy.

Venoarterial PCO-to-arteriovenous oxygen content difference ratio is a poor surrogate for anaerobic metabolism in hemodilution: an experimental study.

Background: The identification of anaerobic metabolism in critically ill patients is a challenging task. Observational studies have suggested that the ratio of venoarterial PCO (PCO) to arteriovenous oxygen content difference (CO) might be a good surrogate for respiratory quotient (RQ). Yet PCO/CO might be increased by other factors, regardless of anaerobic metabolism.

Systemic and microcirculatory effects of blood transfusion in experimental hemorrhagic shock.

Background: The microvascular reperfusion injury after retransfusion has not been completely characterized. Specifically, the question of heterogeneity among different microvascular beds needs to be addressed. In addition, the identification of anaerobic metabolism is elusive.

Intestinal and sublingual microcirculation are more severely compromised in hemodilution than in hemorrhage.

The alterations in O2 extraction in hemodilution have been linked to fast red blood cell (RBC) velocity, which might affect the complete release of O2 from Hb. Fast RBC velocity might also explain the normal mucosal-arterial Pco2 (ΔPco2). Yet sublingual and intestinal microcirculation have not been completely characterized in extreme hemodilution.

Severe abnormalities in microvascular perfused vessel density are associated to organ dysfunctions and mortality and can be predicted by hyperlactatemia and norepinephrine requirements in septic shock patients.

Purpose: The aims of this study are to determine the general relationship of perfused vessel density (PVD) to mortality and organ dysfunctions and to explore if patients in the lowest quartile of distribution for this parameter present a higher risk of bad outcome and to identify systemic hemodynamic and perfusion variables that enhances the probability of finding a severe underlying microvascular dysfunction.

Materials And Methods: This is a retrospective multicenter study including 122 septic shock patients participating in 7 prospective clinical trials on which at least 1 sublingual microcirculatory assessment was performed during early resuscitation.

Results: Perfused vessel density was significantly related to organ dysfunctions and mortality, but this effect was largely explained by patients in the lowest quartile of distribution for PVD (P = .

Comparison of different methods for the calculation of the microvascular flow index.

The microvascular flow index (MFI) is commonly used to semiquantitatively characterize the velocity of microcirculatory perfusion as absent (0), intermittent (1), sluggish (2), or normal (3). There are three approaches to compute MFI: (1) the average of the predominant flow in each of the four quadrants (MFI(by quadrants)), (2) the direct assessment during the bedside video acquisition (MFI(point of care)), and (3) the mean value of the MFIs determined in each individual vessel (MFI(vessel by vessel)). We hypothesized that the agreement between the MFIs is poor and that the MFI(vessel by vessel) better reflects the microvascular perfusion.

Failure of nitroglycerin (glyceryl trinitrate) to improve villi hypoperfusion in endotoxaemic shock in sheep.

Objective: To evaluate the effects of nitroglycerin (glyceryl trinitrate) on intestinal microcirculation during endotoxaemic shock.

Design: Controlled experimental study.

Setting: Research laboratory.

Comparison of 6% hydroxyethyl starch 130/0.4 and saline solution for resuscitation of the microcirculation during the early goal-directed therapy of septic patients.

Purpose: The aim of this study was to show that 6% hydroxyethyl starch (HES) 130/0.4 achieves a better resuscitation of the microcirculation than normal saline solution (SS), during early goal-directed therapy (EGDT) in septic patients.

Materials And Methods: Patients with severe sepsis were randomized for EGDT with 6% HES 130/0.

Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study.

Introduction: Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation.

Methods: Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were mechanically ventilated and required norepinephrine to maintain a mean arterial pressure (MAP) of 65 mmHg.

Systemic and microcirculatory responses to progressive hemorrhage.

Objective: To compare systemic hemodynamics with microcirculatory changes at different vascular beds during progressive hemorrhage.

Setting: University-based research laboratory.

Subjects: Twelve anesthetized, mechanically ventilated sheep.

Persistent villi hypoperfusion explains intramucosal acidosis in sheep endotoxemia.

Objective: To test the hypothesis that persistent villi hypoperfusion explains intramucosal acidosis after endotoxemic shock resuscitation.

Design: Controlled experimental study.

Setting: University-based research laboratory.

Effects of levosimendan and dobutamine in experimental acute endotoxemia: a preliminary controlled study.

Objective: To test the hypothesis that levosimendan increases systemic and intestinal oxygen delivery (DO(2)) and prevents intramucosal acidosis in septic shock.

Design: Prospective, controlled experimental study.

Setting: University-based research laboratory.

Effects of levosimendan in normodynamic endotoxaemia: a controlled experimental study.

Objectives: Levosimendan is an inotropic and vasodilator drug that has proved to be useful in cardiogenic shock. Pretreatment with levosimendan in experimental hypodynamic septic shock in pigs has shown valuable effects in oxygen transport. Our goal was to assess the effects of levosimendan in a normodynamic model of endotoxaemia.

Urinary bladder partial carbon dioxide tension during hemorrhagic shock and reperfusion: an observational study.

Introduction: Continuous monitoring of bladder partial carbon dioxide tension (PCO2) using fibreoptic sensor technology may represent a useful means by which tissue perfusion may be monitored. In addition, its changes might parallel tonometric gut PCO2. Our hypothesis was that bladder PCO2, measured using saline tonometry, will be similar to ileal PCO2 during ischaemia and reperfusion.