Dataset Information

Increased FIO2 influences SvO2 interpretation and accuracy of Fick-based cardiac output assessment in cardiac surgery patients: A prospective randomized study.

ABSTRACT:

Introduction

The study aimed to reveal how the fraction of inspired oxygen (FIO2) affected the value of mixed venous oxygen saturation (SvO2) and the accuracy of Fick-equation-based cardiac output (Fick-CO).

Methods

Forty two adult patients who underwent elective cardiac surgery were enrolled and randomly divided into 2 groups: FIO2 < 0.7 or >0.85. Under stable general anesthesia, thermodilution-derived cardiac output (TD-CO), SvO2, venous partial pressure of oxygen, hemoglobin, arterial oxygen saturation, arterial partial pressure of oxygen, and blood pH levels were recorded before surgical incision.

Results

Significant differences in FIO2 values were observed between the 2 groups (0.56 ± 0.08 in the <70% group and 0.92 ± 0.03 in the >0.85 group; P < .001). The increasing FIO2 values lead to increases in SvO2, venous partial pressure of oxygen, and arterial partial pressure of oxygen, with little effects on cardiac output and hemoglobin levels. When comparing to TD-CO, the calculated Fick-CO in both groups had moderate Pearson correlations and similar linear regression results. Although the FIO2 <0.7 group presented a less mean bias and a smaller limits of agreement, neither group met the percentage error criteria of <30% in Bland-Altman analysis.

Conclusion

Increased FIO2 may influence the interpretation of SvO2 and the exacerbation of Fick-CO estimation, which could affect clinical management.

Trial registration

ClinicalTrials.gov ID number: NCT04265924, retrospectively registered (Date of registration: February 9, 2020).

SUBMITTER: Lin SY

PROVIDER: S-EPMC8428708 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Increased FIO2 influences SvO2 interpretation and accuracy of Fick-based cardiac output assessment in cardiac surgery patients: A prospective randomized study.

Lin Sheng-Yi SY Chang Feng-Cheng FC Lin Jr-Rung JR Chou An-Hsun AH Tsai Yung-Fong YF Liao Chia-Chih CC Tsai Hsin-I HI Chen Chun-Yu CY

Medicine 20210901 36

<h4>Introduction</h4>The study aimed to reveal how the fraction of inspired oxygen (FIO2) affected the value of mixed venous oxygen saturation (SvO2) and the accuracy of Fick-equation-based cardiac output (Fick-CO).<h4>Methods</h4>Forty two adult patients who underwent elective cardiac surgery were enrolled and randomly divided into 2 groups: FIO2 < 0.7 or >0.85. Under stable general anesthesia, thermodilution-derived cardiac output (TD-CO), SvO2, venous partial pressure of oxygen, hemoglobin, a ...[more]

PMID: 34516492

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Project description:The thermodilution (TD) method is routinely used for the estimation of cardiac output (Q̇C). However, its accuracy, compared with the gold-standard Fick method, where systemic oxygen uptake (V̇O2) is directly measured, and Q̇C calculated from V̇O2 and the arterio-venous oxygen difference ("direct" Fick), has not been well validated. The present study determined the agreement between TD and Fick methods in consecutive patients who underwent pulmonary artery catheterization for a broad range of clinical conditions. This is a subanalysis of a previous study comparing the indirect versus Fick method based on a prospective, consecutive patient registry of 253 patients who underwent pulmonary artery catheterization for clinical indications at a single center between 1999 and 2005. We included patients that had an estimation of Q̇C both by the Fick method using measured V̇O2 by exhaled gas analyses from timed Douglas bag collections and by TD. Cardiac index was classified as low when ≤2.2 L/min/m2 or normal when >2.2 L/min/m2. The median (25th, 75th percentile) age of the cohort was 59 (50,67) years, and 50% were female. A total of 43.5% had normal left ventricular function by ventriculography, and 25.7% had ischemic heart disease. Median overall Fick and TD Q̇C were 4.4 (3.5, 5.5) and 4.3 (3.7, 5.2) L/min, respectively (p = 0.04). The median absolute percent error between Fick and TD Q̇C was 17.5 (7.7, 28.4)%, with a typical error of 0.88 L/min (95% confidence interval [CI] 0.82 to 0.95). Median absolute percent error was comparable in the low (n = 118) and normal Q̇CI (n = 135) groups (16.9% vs 18.9%, respectively, p = 0.88). typical error was 0.3 (95% CI 0.27 to 0.33) and 0.49 (95% CI 0.45 to 0.55) L/min/m2 in that comparison. Percent error >25% between Fick and TD Q̇C was observed in over 30% of patients. Overall, Fick and TD Q̇C modestly correlated (Rs = 0.64, p <0.001), with a nondirectional error introduced by TD Q̇C [mean bias of 0.21 (-2.2, 2.7) L/min]. There was poor agreement between TD and the gold-standard Fick method, highlighting the limitations of making clinical decisions based on TD.

Project description:IntroductionRight heart catheterization (RHC) is a diagnostic procedure, the main purpose of which is to diagnose pulmonary hypertension and investigate its etiology and treatability. In addition to measuring blood pressure in heart chambers, it includes estimating cardiac output (CO) and calculation of pulmonary vascular resistance (PVR) derived from the CO. There are two common methods to evaluate the CO-the indirect Fick method and the thermodilution method. Depending on the clinical conditions, either of the two may be considered better. Several studies have showed that, in most cases, there is no difference between measurements rendered by the two methods. Other studies have raised suspicion of a discrepancy between the two methods in a substantial number of patients. A clear opinion on this matter is missing.AimTo evaluate the agreement between the values of the CO and PVR found by the thermodilution and indirect Fick methods.MethodsWe retrospectively included patients that underwent RHC in Kaplan Medical Center during the last two years with a measurement of the CO using both the thermodilution and the indirect Fick methods. The measurements obtained upon RHC and the clinical data of the patients were collected. The values of the CO and PVR measured or calculated using the two methods were compared for each patient.ResultsWe included 55 patients that met the inclusion criteria in this study. The mean CO measured by the thermodilution method was 4.94 ± 1.17 L/min and the mean CO measured by the indirect Fick method was 5.82 ± 1.97 L/min. The mean PVR calculated using the thermodilution method was 3.33 ± 3.04 Woods' units (WU) and the mean PVR calculated using the indirect Fick method was 2.71 ± 2.76 WU. Among the patients with normal mPAP, there was a strong and statistically significant correlation between the PVR values calculated by the two methods (Peasron's R2 = 0.78, p-value = 0.004), while among the patients with elevated mPAP, the correlation between the PVR values calculated by the two methods was not statistically significant.ConclusionThe findings of this small study demonstrate that, in a proportion of patients, the indirect Fick method and thermodilution method classify the PVR value differently. In our experience, it seems that, in these patients, the indirect Fick method misclassified patients with a pathological finding as normal. We, therefore, recommend that upon performing RHC, at least in patients with mPAP > 25 mmHg, both the thermodilution and indirect Fick methods be performed and, whenever they disagree, the values obtained from the thermodilution method should be preferred.

Project description:BackgroundLess invasive monitoring, such as radial arterial pulse contour analysis (ProAQT® sensor), represents an alternative when hemodynamic monitoring is necessary to guide postoperative management and invasive monitoring is not technically feasible. The aim of the study is to evaluate the accuracy of the ProAQT® sensor cardiac output measurements in comparison with Pulmonary Artery Catheter (PAC) during the postoperative course of patients who underwent cardiac surgery with cardiopulmonary bypass.Case presentationProspective observational study in a Surgical Intensive Care Unit of a tertiary university hospital. Ten patients with a mean age of 73.5 years were included. The main comorbidities were hypertension, diabetes, dyslipidemia and the preoperative left ejection fraction was 43.8 ± 14.5%. Regarding the type of surgery, six patients underwent valve surgery, two underwent coronary artery bypass grafting and two underwent aortic surgery. The cardiac index measured simultaneously by the ProAQT® sensor was compared with the PAC. The parameters were evaluated at predefined time points during the early postoperative courses (6 h, 12 h, 24 h, 48 h and 72 h). The degree of agreement with the cardiac index between the PAC and the ProAQT® sensor along the time points was measured using the concordance correlation coefficient, Bland-Altman analysis, and four-quadrant plot. Sixty-three pairs of measurements were analyzed. We showed that measurements of cardiac index were slightly higher with PAC (β ̂ = - 0.146, p-value = 0.094). The concordance correlation coefficient for the additive model of cardiac index was 0.64 (95% Confidence Interval: 0.36, 0.82), indicating a high concordance between both sensors. Bland-Altmann analysis showed a mean bias of 0.45 L·min-1·m-2, limits of agreement from - 1.65 to 2.3 L·min-1·m-2, and percentage of error was 82.5%. Four-quadrant plot of changes in cardiac index showed a good concordance rate (75%), which increases after applying the exclusion zone (87%).ConclusionsIn patients undergoing cardiac surgery, the ProAQT® sensor may be useful to monitor cardiac index during the postoperative period, especially when more invasive monitoring is not possible.

Dataset Information

Increased FIO2 influences SvO2 interpretation and accuracy of Fick-based cardiac output assessment in cardiac surgery patients: A prospective randomized study.

Introduction

Methods

Results

Conclusion

Trial registration

Publications

Increased FIO2 influences SvO2 interpretation and accuracy of Fick-based cardiac output assessment in cardiac surgery patients: A prospective randomized study.

Similar Datasets

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