The validity of central venous to arterial carbon dioxide difference to predict adequate fluid management during living donor liver transplantation. A prospective observational study

Mohamed Elayashy,Amr Abdelaal,Ahmed Mukhtar,Hisham Hosny,Amr Hussein,Ahmed Abdelaal Ahmed Mahmoud,Mostafa Abdo,Fawzia Aboulfetouh,Hany Said,Amira El-Khateeb,Mohamed Wagih

doi:10.1186/s12871-019-0776-9

Mohamed Elayashy, Amr Abdelaal + Show 9 more

Open Access

https://doi.org/10.1186/s12871-019-0776-9

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Abstract

BackgroundTo assess the validity of central and pulmonary veno-arterial CO2 gradients to predict fluid responsiveness and to guide fluid management during liver transplantation.MethodsIn adult recipients (ASA III to IV) scheduled for liver transplantation, intraoperative fluid management was guided by pulse pressure variations (PPV). PPV of ≥15% (Fluid Responding Status-FRS) indicated fluid resuscitation with 250 ml albumin 5% boluses repeated as required to restore PPV to < 15% (Fluid non-Responding Status-FnRS). Simultaneous blood samples from central venous and pulmonary artery catheters (PAC) were sent to calculate central venous to arterial CO2 gap [C(v-a) CO2 gap] and pulmonary venous to arterial CO2 gap [Pulm(p-a) CO2 gap]. CO and lactate were also measured.ResultsSixty seven data points were recorded (20 FRS and 47 FnRS). The discriminative ability of central and pulmonary CO2 gaps between the two states (FRS and FnRS) was poor with AUC of ROC of 0.698 and 0.570 respectively. Central CO2 gap was significantly higher in FRS than FnRS (P = 0.016), with no difference in the pulmonary CO2 gap between both states. The central and Pulmonary CO2 gaps are weakly correlated to PPV [r = 0.291, (P = 0.017) and r = 0.367, (P = 0.002) respectively]. There was no correlation between both CO2 gaps and both CO and lactate.ConclusionCentral and the Pulmonary CO2 gaps cannot be used as valid tools to predict fluid responsiveness or to guide fluid management during liver transplantation. CO2 gaps also do not correlate well with the changes in PPV or CO.Trial registrationClinicaltrials.gov Identifier: NCT03123172. Registered on 31-march-2017.

Highlights

To assess the validity of central and pulmonary veno-arterial Mixed venous-to-arterial CO2 tension gap (CO2) gradients to predict fluid responsiveness and to guide fluid management during liver transplantation
In the dissection phase; bleeding and hypovolemia are frequent [1], while in the an-hepatic period venous return may decrease resulting in a reduction in left ventricular preload [2] while after de-clamping and starting the neo-hepatic phase, the reperfusion injury and metabolic derangement can be severe enough to cause serious consequences [3]
We hypothesize that CO2 gaps can be a complementary tool to pulse pressure variations (PPV) to guide adequate fluid management. This prospective observational study was approved by the Research Ethics Committee of Kasr Al-Ainy faculty of medicine, Cairo University (N-21-2017) and written informed consents was obtained from all study participants

Summary

Introduction

To assess the validity of central and pulmonary veno-arterial CO2 gradients to predict fluid responsiveness and to guide fluid management during liver transplantation. End-stage liver disease (ESLD) patients undergoing orthotopic liver transplantation can be prone to severe hemodynamic and metabolic changes. Adequate tissue perfusion is an essential component of oxygenation during high-risk surgery and may improve the outcome [4, 5]. The early warning signals of tissue hypoxia, such as lactate, central venous to arterial CO2 gradient and central venous oxygen saturation (ScvO2, 8], are essential indicators of the changes in the O2 delivery/consumption (DO2/VO2) relationship during high-risk surgery [8,9,10]. Pulm(P-a) CO2 does not exceed 6 mmHg. Elevated [Pulm(P-a) CO2] gradient has been observed in all types of circulatory failure (cardiogenic, obstructive, hypovolemic and distributive shock) [12]

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