Observations on significant hemodynamic changes caused by a high concentration of epidurally administered ropivacaine: correlation and prediction study of stroke volume variation and central venous pressure in thoracic epidural anesthesia

Abstract

Background: Thoracic epidural anesthesia (TEA) exacerbates hypotension due to peripheral vasodilator effects following the use of general anesthetics. This study aimed to compare the hemodynamic changes caused by three different concentrations of epidural ropivacaine and to evaluate the performance of the stroke-volume variation (SVV) and central venous pressure (CVP) during TEA with general anesthesia.

Methods: A total of 120 patients were administered 8 mL of ropivacaine solution via epidural injection, following randomization into one of three groups based on the concentration of ropivacaine in the study solution: 0.75%, 0.375%, or 0.2%. Hemodynamics were monitored for 30 min after loading. We analyzed the hemodynamic changes in the subgroups according to an age cutoff of 60 years. Receiver operating characteristic (ROC) analysis was performed to characterize the relationship of the SVV, CVP, and a 20% decrease in the mean arterial pressure (MAP) following TEA.

Results: Data from 109 patients were analyzed. MAP and systemic vascular resistance index were significantly decreased, and SVV was significantly increased after epidural loading only in the 0.75% ropivacaine group. There was a significant difference in hemodynamics between young and elderly subgroups in the 0.75% ropivacaine group. SVV showed a negative correlation with MAP, whereas CVP showed no correlation. The ROC analysis of SVV demonstrated a weak predictive ability of a 20% decrease in MAP at 10 min after the loading dose, with an area-under-the-curve of 0.687 and a 9.5% optimal cutoff value (sensitivity, 60.6%; specificity, 68.9%).

Conclusions: A high concentration of ropivacaine through TEA caused a significant decrease in the systemic vascular resistance and blood pressure. More significant decreases were shown in the elderly patients. Though the change of SVV showed a negative correlation with hypotension and indicated functional hypovolemia after TEA, the predictability was limited.

Clinical trials registration: Number: NCT01559285 , date: January 24, 2013.

Keywords: Epidural administration; Epidural, local, ropivacaine; Stroke volume variability.

Conflict of interest statement

Ethics approval and consent to participate

The study was approved by IRB of the Yangsan Hospital of Pusan National University with the number 05–2011-054. The written informed consent was obtained from patients.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

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Figures

Fig. 1

Consort flow diagram

Fig. 2

Hemodynamic changes following epidural administration of ropivacaine. MAP (P = 0.039) and SVRI (P = 0.026) were significantly decreased in 0.75% ropivacaine group compared with other groups. Concordant increase in SVV was remarkably increased in 0.75% group compared with 0.375% and 0.2% group through the study period (P = 0.017). * mean P < 0.05 compared with 0.2% group and † means P < 0.05 compared with 0.375% group

Fig. 3

Receiver operating characteristics (ROC) curve analyses to predict change of mean arterial blood pressure after thoracic epidural anesthesia. The AUC of SVV was 0.687 (95% CI, 0.587–0.787) whereas AUC of CVP (0.477 [95% CI, 0.369–0.584]). The performance to predict 20% change of mean arterial pressure was significantly different (P = 0.026). The optimal cutoff value of SVV to discriminate between responders and non-responders was 9.5% (sensitivity: 60.6%, specificity: 68.9%)