ABSTRACT
Background: Maximizing the stroke volume (SV) as measured by Trans-oesophageal Doppler (TED) optimizes preload, & is a goal-directed fluid therapy technique that has been used in a variety of clinical settings. Masimo® Plethysmograph variability Index (PVI) is a reliable, safe & noninvasive tool to guide fluid management. PVI is an automated measure of the dynamic change in the perfusion index (PI) that occurs during a respiratory cycle. This study was designed to determine whether PVI, measured using finger co-oximetry is an efficient predictor of fluid responsiveness in low-risk patients undergoing elective major abdominal surgery. Subjects and Methods: 60 ASA I-II patients of either sex, 25-60 years old, undergoing major abdominal surgery were enrolled in this study. A Masimo® Radical-7 Pulse Co-Oximeter probe & a Cardio Q TED probe were applied to each patient. In all patients, a fluid bolus of 500 ml of 130/0.4 tetrastarch colloid solution was administered rapidly via pressurized IV infusion. Maintenance & deficits were calculated routinely. If the SV decreased by 10%, a 250-mL bolus of colloid was given via fast infusion. Patients’ demography, TED-derived measurements: (SV & Flow Time corrected (FTc)), Masimo®-derived measurements: (PVI & PI), HR and MAP were all collected and statistically analyzed. Measurements were done at five minutes post-induction T1, Ten minutes after volume expansion (500 ml colloid) T2, If the SV decreased by 10%, (guided by TED) T3, Then 250 ml colloid is given. Ten minutes after a 250-ml colloid bolus T4. Results: A significant difference was found in FTc, SV, PI & PVI in T1 vs. T2 & T3 vs. T4 (P=0.001). There was a significant difference in PI & PVI between responders & non-responders for the 1st bolus (P<0.05) and in SV & PVI in subsequent boluses (P<0.01). There was no significant difference between percent changes of SV and PVI at T3 & T4. Conclusions: Plethysmograph Variability Index (PVI) measured by Masimo® Co-Oximeter is an efficient predictor of fluid responsiveness as SV measured by TED in low risk patients undergoing elective major surgery.
ABSTRACT
BACKGROUND: We hypothesized that induction of general anesthesia using sevoflurane improves the accuracy of non-invasive hemoglobin (SpHb) measurement of Masimo Radical-7(R) Pulse CO-Oximetry by inducing peripheral vasodilation and increasing the perfusion index (PI). The aim of this study is to investigate the change in the SpHb and the PI measured by Rad7 during induction of general anesthesia using sevoflurane. METHODS: The laboratory hemoglobin (Hb(lab)) was measured before surgery by venous blood sampling. The SpHb and the PI was measured twice; before and after the induction of general anesthesia using sevoflurane. The changes of SpHb, Hb(bias) (Hb(bias) = SpHb - Hb(lab)), and PI before and after the induction of general anesthesia were analyzed using a paired t-test. Also, a Pearson correlation coefficient analysis was used to analyze the correlation between the Hb(bias) and the PI. RESULTS: The SpHb and the PI were increased after the induction of general anesthesia using sevoflurane. There was a statistically significant change in the Hb(bias) from -2.8 to -0.7 after the induction of general anesthesia. However, the limit of agreement (2 SD) of the Hb(bias) did not change after the induction of general anesthesia. The Pearson correlation coefficient between the Hb(bias) and the PI was not statistically significant. CONCLUSIONS: During induction of general anesthesia using sevoflurane, the accuracy of SpHb measurement was improved and precision was not changed. The correlation between Hb(bias) and PI was not significant.
Subject(s)
Anesthesia, General , Perfusion , VasodilationABSTRACT
Objective To study the changes of pleth variability index (PVI) in patients receiving laparoscopic cholecystectomy under general anesthesia, and to investigate the clinical influencing factors of pre-operation baseline PVI value. Methods Totally 67 patients undergoing laparoscopic cholecystectomy with ASA?-II, aged 18 to 65 years old, were included in the present study. The heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse oximetry (SpO2), perfusion index (PI), and PVI value were monitored with a Masimo pulse oxygen monitor (Radical-7, USA) after entering the operation room. Fluid expansion with 10 mL/kg of balanced solution was given before the induction. Anesthesia was maintained under total intravenous anesthesia (TIVA) with propofol and remifentanil. Results The average baseline PVI value was (16.8±6.3)% in the patients; then it decreased to (10.3±5.4)% after induction of anesthesia and increased to (21.2±9.5)% after establishment of pneumoperitoneum. The pre-operation baseline PVI value (\[19.2±6.5\] %) of patients <45 years old was significantly higher than that in patients ≥45 years old (\[15.5±5.9\]%, P<0.05%). Male patients had a significantly higher PVI (\[18.8±7.5\]%) value than female patients (\[15.3±4.8\]%, P<0.05). Body mass index (BMI) was not significantly associated with pre-operation baseline PVI. Conclusion The baseline value of PVI is higher than 14%, suggesting insufficient volume load in most of patients. Age and sex are both associated with pre-operation PVI value: male patients and those <45 years old have a higher pre-operation baseline PVI value.