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@#BACKGROUND: In the management of critically ill patients, the assessment of volume responsiveness and the decision to administer a fluid bolus constitute a common dilemma for physicians. Static indices of cardiac preload are poor predictors of volume responsiveness. Passive leg raising (PLR) mimics an endogenous volume expansion (VE) that can be used to predict fluid responsiveness. This study was to assess the changes in stroke volume index (SVI) induced by PLR as an indicator of fluid responsiveness in mechanically ventilated patients with severe sepsis. METHODS: This was a prospective study. Thirty-two mechanically ventilated patients with severe sepsis were admitted for VE in ICU of the First Affiliated Hospital, Zhejiang University School of Medicine and Ningbo Medical Treatment Center Lihuili Hospital from May 2010 to December 2011. Patients with non-sinus rhythm or arrhythmia, parturients, and amputation of the lower limbs were excluded. Measurements of SVI were obtained in a semi-recumbent position (baseline) and during PLR by the technique of pulse indicator continuous cardiac output (PiCCO) system prior to VE. Measurements were repeated after VE (500 mL 6％ hydroxyethyl starch infusion within 30 minutes) to classify patients as either volume responders or non-responders based on their changes in stroke volume index (ΔSVI) over 15％. Heart rate (HR), systolic artery blood pressure (ABPs), diastolic artery blood pressure (ABPd), mean arterial blood pressure (ABPm), mean central venous pressure (CVPm) and cardiac index (CI) were compared between the two groups. The changes of ABPs, ABPm, CVPm, and SVI after PLR and VE were compared with the indices at the baseline. The ROC curve was drawn to evaluate the value of ΔSVI and the change of CVPm (ΔCVPm) in predicting volume responsiveness. SPSS 17.0 software was used for statistical analysis. RESULTS: Among the 32 patients, 22 were responders and 10 were non-responders. After PLR among the responders, some hemodynamic variables (including ABPs, ABPd, ABPm and CVPm) were significantly elevated (101.2±17.6 vs.118.6±23.7,P=0.03; 52.8±10.7 vs. 64.8±10.7,P=0.006; 68.3±11.7 vs. 81.9±14.4,P=0.008; 6.8±3.2 vs. 11.9±4.0,P=0.001). After PLR, the area under curve (AUC) and the ROC curve of ΔSVI and ΔCVPm for predicting the responsiveness after VE were 0.882±0.061 (95％CI 0.759–1.000) and 0.805±0.079 (95％CI 0.650–0.959) when the cut-off levels of ΔSVI and ΔCVPm were 8.8％ and 12.7％, the sensitivities were 72.7％ and 72.7％, and the specificities were 80％ and 80％. CONCLUSION: Changes in ΔSVI and ΔCVPm induced by PLR are accurate indices for predicting fluid responsiveness in mechanically ventilated patients with severe sepsis.
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Objective: To investigate the efficacies of heart rate (HR), mean artery pressure (MAP), central venous pressure (CVP), pulmonary artery wedge pressure (PAWP) and stroke volume variation (SVV) in assessing low stroke volume index (SVI) caused by volume deficiency in major non-cardiac surgeries. Methods: Twelve patients undergoing sacral or retroperitoneal tumor resection were enrolled in this study. After induction and onset of mechanical ventilation, radial artery was cannulated and connected to FloTrac for BP and SVV monitoring. Swan-Ganz catheter was placed via internal jugular vein into the pulmonary artery for CVP, PAWP, and SVI monitoring. HR, MAP, CVP, PAWP, SVV, and SVI were recorded every 30 min. If phenylephrine was injected within 5 min before the time point for data-record, the record should be postponed to 5 min after the injection. If vasoconstrictor or cardiotonic was injected intravenously and continuously to keep the normal blood pressure, the data-record in this patient should be stopped then, otherwise it should be stopped when the concentration of sevoflurane was turned lower at the end stage of the operation. The receiver operating characteristic (ROC) curves of HR, MAP, CVP, PAWP, and SVV were made according to a low stroke volume which was less than 25 ml/m2 and AUC (area under curve) were counted. Results: The AUC of SVV for assessment of a low SVI was 0.837, while AUC of HR, MAP, CVP and PAWP were 0.615, 0.647, 0.623, and 0.658, respectively. The highest Youden's index was at the point when SVV was 9.5% in its ROC curve, with a sensitivity of 82.4% and specificity of 74.6%. Conclusion: SVV is a middle-level effective variable to assess the abnormally low SVI caused by volume deficiency, while HR, MAP, CVP and PAWP have a low efficacy for the same assessment.
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BACKGROUND: Remifentanil-propofol combination is used to minimize the cardiovascular responses during anesthetic induction; however, it may generate side effects such as hypotension or bradycardia. The authors investigated the changes of stroke volume and cardiac output using impedance cardiography (ICG) when hypotension or bradycardia is generated during propofol-remifentanil anesthetic induction. METHODS: Ninety ASA physical status class I patients who were scheduled to undergo elective ambulatory surgery were randomly assigned to one of three groups (n = 30 each). Normal saline (Group S), remifentanil 0.25microgram/kg/min (Group R0.25), or remifentanil 0.5microgram/kg/min (Group R0.5) was infused intravenously. Propofol was slowly administered two minutes after the administration of remifentanil or normal saline. Heart rate, mean arterial pressure, cardiac output and stroke volume were measured at preinduction (baseline), preintubation and postintubation. RESULTS: Mean arterial pressure in Group R0.5 at preintubation decreased compared to that of the baseline, however, the stroke volume index was sustained. The stroke volume index at postintubation decreased proportionally as heart rate increased in heart rate in all groups, and then cardiac index was preserved. CONCLUSIONS: Hypotension was generated during induction of anesthesia when remifentanil 0.5microgram/kg/min and propofol 1.0 mg/kg were used, however, the stroke volume index was sustained.
Subject(s)
Humans , Ambulatory Surgical Procedures , Anesthesia , Arterial Pressure , Bradycardia , Cardiac Output , Cardiography, Impedance , Electric Impedance , Heart Rate , Hemodynamics , Hypotension , Propofol , Stroke VolumeABSTRACT
BACKGROUND: It is important to assess cardiac preload for management of patients undergoing off pump coronary artery bypass surgery (OPCAB). Recently, several studies have documented the good correlation between right ventricular end-diastolic volume index (RVEDVI) and stroke volume index (SVI), compared with cardiac filling pressures. However, none of these studies have evaluated relationship between predictors of preload and SVI measured with volumetric pulmonary artery catheter during OPCAB. The correlation of continuous RVEDVI and SVI measured with volumetric pulmonary artery catheter during OPCAB was evaluated in this study. METHODS: Fifty three patients undergoing OPCAB were included. Hemodynamic parameters were measured 10 min after induction (T1), 10 min after Y-graft formation started (T2) and 10 min after sternum closure (T3). The correlation of parameters were assessed by simple linear regression. RESULTS: Central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) did not correlate with SVI during OPCAB. On the other hand, a statistically significant result was found between RVEDVI and SVI at T2 (r(2)=0.133, P=0.007) and T3 (r(2)=0.380, P < 0.000). But RVEDVI and SVI were weakly correlated. And at T1, RVEDVI and SVI did not correlate. CONCLUSIONS: RVEDVI is a more reliable predictor of preload compared to CVP and PAOP during OPCAB. But in post-induction period (T2), RVEDVI did not correlate with SVI.