Stroke volume variation (SVV) and pulse pressure variation (PPV) are used as indicators of fluid responsiveness, but little is known about the usefulness of these dynamic preload indicators in thoracic surgery, which involves an open thoracic cavity and 1-lung ventilation (OLV). Therefore, we investigated whether SVV and PPV could predict fluid responsiveness, and whether the thresholds of these parameters should be adjusted for thoracic surgery.METHODS:
This was a prospective, controlled study conducted in a tertiary care center. Eighty patients scheduled for an elective lobectomy requiring OLV were included (n = 40, video-assisted thoracoscopic surgery (VATS); n = 40, open thoracotomy). Twenty minutes after opening the thoracic cavity, 7 mL/kg hydroxyethyl starch was administered for 30 minutes. Various hemodynamic parameters were measured before and after fluid challenge.RESULTS:
Among the 80 patients enrolled in this study, 37% were fluid responders (increase in stroke volume index ≥10%). SVV before fluid challenge was not different between nonresponders and responders (mean ± SD: 7.1 ± 2.7% vs 7.4 ± 2.6%, P = .68). This finding was true regardless of whether the surgery involved open thoracotomy or VATS. PPV before fluid challenge showed the difference between nonresponders and responders (mean ± SD: 6.9 ± 3.0% vs 8.4 ± 3.2%; P = .045); however, the sensitivity and specificity of the threshold value (PPV = 7%) were low (58% and 62%, respectively) and the area under the receiver operating characteristics curve was only 0.63 (95% confidence interval, 0.52–0.74; P = .041).CONCLUSIONS:
Dynamic preload indicators are not useful for predicting fluid responsiveness in VATS or open thoracic surgery.