Volker Eichhorn

Goal-Directed Fluid Therapy Using Stroke Volume Variation Does Not Result in Pulmonary Fluid Overload in Thoracic Surgery Requiring One-Lung Ventilation

Background. Goal-directed fluid therapy (GDT) guided by functional parameters of preload, such as stroke volume variation (SVV), seems to optimize hemodynamics and possibly improves clinical outcome. However, this strategy is believed to be rather fluid aggressive, and, furthermore, during surgery requiring thoracotomy, the ability of SVV to predict volume responsiveness has raised some controversy. So far it is not known whether GDT is associated with pulmonary fluid overload and a deleterious reduction in pulmonary function in thoracic surgery requiring one-lung-ventilation (OLV). Therefore, we assessed the perioperative course of extravascular lung water index (EVLWI) and paO2/FiO2-ratio during and after thoracic surgery requiring lateral thoracotomy and OLV to evaluate the hypothesis that fluid therapy guided by SVV results in pulmonary fluid overload. Methods. A total of 27 patients (group T) were enrolled in this prospective study with 11 patients undergoing lung surgery (group L) and 16 patients undergoing esophagectomy (group E). Goal-directed fluid management was guided by SVV (SVV < 10%). Measurements were performed directly after induction of anesthesia (baseline—BL), 15 minutes after implementation OLV (OLVimpl15), and 15 minutes after termination of OLV (OLVterm15). In addition, postoperative measurements were performed at 6 (6postop), 12 (12postop), and 24 (24postop) hours after surgery. EVLWI was measured at all predefined steps. The paO2/FiO2-ratio was determined at each point during mechanical ventilation (group L: BL-OLVterm15; group E: BL-24postop). Results. In all patients (group T), there was no significant change (P > 0.05) in EVLWI during the observation period (BL: 7.8 ± 2.5, 24postop: 8.1 ± 2.4 mL/kg). A subgroup analysis for group L and group E also did not reveal significant changes of EVLWI. The paO2/FiO2-ratio decreased significantly during the observation period (group L: BL: 462 ± 140, OLVterm15: 338 ± 112 mmHg; group E: BL: 389 ± 101, 24postop: 303 ± 74 mmHg) but remained >300 mmHg except during OLV. Conclusions. SVV-guided fluid management in thoracic surgery requiring lateral thoracotomy and one-lung ventilation does not result in pulmonary fluid overload. Although oxygenation was reduced, pulmonary function remained within a clinically acceptable range.

Comparison of values in critically ill patients for global end-diastolic volume and extravascular lung water measured by transcardiopulmonary thermodilution: A metaanalysis of the literature

INTRODUCTION Hemodynamic parameters such as the global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI), derived by transpulmonary thermodilution, have gained increasing interest for guiding fluid therapy in critically ill patients. The proposed normal values (680-800ml/m(2) for GEDVI and 3-7ml/kg for EVLWI) are based on measurements in healthy individuals and on expert opinion, and are assumed to be suitable for all patients. We analyzed the published data for GEDVI and EVLWI, and investigated the differences between a cohort of septic patients (SEP) and patients undergoing major surgery (SURG), respectively. METHODS A PubMed literature search for GEDVI, EVLWI or transcardiopulmonary single/double indicator thermodilution was carried out, covering the period from 1990 to 2010. INTERVENTION Meta-regression analysis was performed to identify any differences between the surgical (SURG) and non-surgical septic groups (SEP). RESULTS Data from 1925 patients corresponding to 64 studies were included. On comparing both groups, mean GEDVI was significantly higher by 94ml/m(2) (95%CI: [54; 134]) in SEP compared to SURG patients (788ml/m(2) 95%CI: [762; 816], vs. 694ml/m(2), 95%CI: [678; 711], p<0.001). Mean EVLWI also differed significantly by 3.3ml/kg (95%CI: [1.4; 5.2], SURG 7.2ml/kg, 95%CI: [6.9; 7.6] vs. SEP 11.0ml/kg, 95%CI: [9.1; 13.0], p=0.001). CONCLUSIONS The published data for GEDVI and EVLWI are heterogeneous, particularly in critically ill patients, and often exceed the proposed normal values derived from healthy individuals. In the group of septic patients, GEDVI and EVLWI were significantly higher than in the group of patients undergoing major surgery. This points to the need for defining different therapeutic targets for different patient populations.

Thermodilution-derived indices for assessment of left and right ventricular cardiac function in normal and impaired cardiac function.

Objective:The aim of this study was to assess whether thermodilution-derived parameters of right and left ventricular cardiac function (right ventricular ejection fraction, global ejection fraction, cardiac function index) are able to track changes of cardiac contractile function and whether they are influenced by substantial preload reduction. Design:Prospective animal study. Setting:University-affiliated animal research laboratory. Subjects:Domestic pigs. Interventions:Sixteen domestic pigs were studied. Right ventricular ejection fraction, global ejection fraction, and cardiac function index were compared to direct measurement of left ventricular rate of maximum systolic pressure rise and the left ventricular rate of maximum systolic pressure rise corrected to preload. Measurements were done with normal cardiac function during normo- and hypovolemia. Thereafter, cardiac function was impaired by continuous infusion of verapamil and measurements were repeated during normo- and hypovolemia (withdrawal of blood 20 mL kg−1 body weight). Measurements and Main Results:With normal cardiac function, hypovolemia led to a significant decrease of right ventricular ejection fraction from 36.7% ± 6.6% to 29.8% ± 5.8% (p < .001), global ejection fraction from 40.5% ± 6.2% to 33.6% ± 7.6% (p < .001), and the left ventricular rate of maximum systolic pressure rise from 2104 ± 390 mm Hg sec−1 to 1297 ± 438 mm Hg sec−1 (p < .001). Cardiac function index (8.92 ± 2.20 min−1 to 7.93 ± 1.54 min−1) and the left ventricular rate of maximum systolic pressure rise corrected to preload (18.2 ± 4.7 mm Hg sec−1 mL to 15.2 ± 4.3 mm Hg sec−1 mL) did not change significantly. Infusion of verapamil led to a significant reduction of right ventricular ejection fraction, global ejection fraction, cardiac function index, the left ventricular rate of maximum systolic pressure rise, and the left ventricular rate of maximum systolic pressure rise corrected to preload (p < .001). Now, hypovolemia led to a significant decrease of right ventricular ejection fraction (29.1% ± 4.6% to 24.9% ± 5.9%; p < .001), global ejection fraction (37.1% ± 4.7% to 31.9% ± 3.9%; p < .05), cardiac function index (7.58 ± 1.02 to 6.27 ± 1.19 min−1; p < .05), and the left ventricular rate of maximum systolic pressure rise (733 ± 141 mm Hg sec−1 to 426 ± 108 mm Hg sec−1; p < .05). Only the left ventricular rate of maximum systolic pressure rise corrected to preload did not change significantly (6.7 ± 1.3 mm Hg sec−1 mL to 4.6 ± 1 mm Hg sec−1 mL; p > .05). Conclusions:Right ventricular ejection fraction, global ejection fraction, and cardiac function index enable detection of changes in load-independent, intrinsic cardiac contractility. Importantly, they also reflect changes of contractile function caused by substantial decrease of preload, emphasizing the importance of assessing both cardiac contractile function in coherence with cardiac preload to differentiate between reduced intrinsic contractility and hypovolemia.

Comparison of an automated respiratory systolic variation test with dynamic preload indicators to predict fluid responsiveness after major surgery

BACKGROUND Predicting the response of cardiac output to volume administration remains an ongoing clinical challenge. The objective of our study was to compare the ability to predict volume responsiveness of various functional measures of cardiac preload. These included pulse pressure variation (PPV), stroke volume variation (SVV), and the recently launched automated respiratory systolic variation test (RSVT) in patients after major surgery. METHODS In this prospective study, 24 mechanically ventilated patients after major surgery were enrolled. Three consecutive volume loading steps consisting of 300 ml 6% hydroxyethylstarch 130/0.4 were performed and cardiac index (CI) was assessed by transpulmonary thermodilution. Volume responsiveness was considered as positive if CI increased by >10%. RESULTS In total 72 volume loading steps were analysed, of which 41 showed a positive volume response. Receiver operating characteristic (ROC) curve analysis revealed an area under the curve (AUC) of 0.70 for PPV, 0.72 for SVV and 0.77 for RSVT. Areas under the curves of all variables did not differ significantly from each other (P>0.05). Suggested cut-off values were 9.9% for SVV, 10.1% for PPV, and 19.7° for RSVT as calculated by the Youden Index. CONCLUSION In predicting fluid responsiveness the new automated RSVT appears to be as accurate as established dynamic indicators of preload PPV and SVV in patients after major surgery. The automated RSVT is clinically easy to use and may be useful in guiding fluid therapy in ventilated patients.

Respiratory systolic variation test in acutely impaired cardiac function for predicting volume responsiveness in pigs

BACKGROUND Predicting the response of cardiac output (CO) to volume administration remains difficult, in particular in patients with acutely compromised cardiac function, where, even small amounts of i.v. fluids can lead to volume overload. We compared the ability to predict volume responsiveness of different functional haemodynamic parameters, such as pulse pressure variation (PPV), stroke volume variation (SVV), the static preload parameter right atrial pressure (RAP), and global end-diastolic volume (GEDV) with the recently proposed respiratory systolic variation test (RSVT) in acutely impaired cardiac function. METHODS In 13 mechanically ventilated pigs, cardiac function was acutely reduced by continuous application of verapamil to reach a decrease in peak change of left ventricular pressure over time (dP/dt) of 50%. After withdrawal of 20 ml kg(-1) BW blood to establish hypovolaemia, four volume loading steps of 7 ml kg(-1) BW using the shed blood and 6% hydroxyethylstarch 130/0.4 were performed. Volume responsiveness was considered as positive, if CO increased more than 10%. RESULTS Receiver operating characteristic curve analysis revealed an area under the curve (AUC) of 0.88 for the RSVT, 0.84 for PPV, 0.82 for SVV, 0.78 for RAP, and 0.77 for GEDV. CONCLUSIONS Functional parameters of cardiac preload, including the RSVT, allow prediction of fluid responsiveness in an experimental model of acutely impaired cardiac function.