Ability of pleth variability index to detect hemodynamic changes induced by passive leg raising in spontaneously breathing volunteers

IntroductionPleth Variability Index (PVI) is a new algorithm that allows continuous and automatic estimation of respiratory variations in the pulse oximeter waveform amplitude. Our aim was to test its ability to detect changes in preload induced by passive leg raising (PLR) in spontaneously breathing volunteers.MethodsWe conducted a prospective observational study. Twenty-five spontaneously breathing volunteers were enrolled. PVI, heart rate and noninvasive arterial pressure were recorded. Cardiac output was assessed using transthoracic echocardiography. Volunteers were studied in three successive positions: baseline (semirecumbent position); after PLR of 45 degrees with the trunk lowered in the supine position; and back in the semirecubent position.ResultsWe observed significant changes in cardiac output and PVI during changes in body position. In particular, PVI decreased significantly from baseline to PLR (from 21.5 +/- 8.0% to 18.3 +/- 9.4%; P < 0.05) and increased significantly from PLR to the semirecumbent position (from 18.3 +/- 9.4% to 25.4 +/- 10.6 %; P < 0.05). A threshold PVI value above 19% was a weak but significant predictor of response to PLR (sensitivity 82%, specificity 57%, area under the receiver operating characteristic curve 0.734 +/- 0.101).ConclusionPVI can detect haemodynamic changes induced by PLR in spontaneously breathing volunteers. However, we found that PVI was a weak predictor of fluid responsiveness in this setting

Ability of pleth variability index to detect hemodynamic changes induced by passive leg raising in spontaneously breathing volunteers.

IntroductionPleth Variability Index (PVI) is a new algorithm that allows continuous and automatic estimation of respiratory variations in the pulse oximeter waveform amplitude. Our aim was to test its ability to detect changes in preload induced by passive leg raising (PLR) in spontaneously breathing volunteers.MethodsWe conducted a prospective observational study. Twenty-five spontaneously breathing volunteers were enrolled. PVI, heart rate and noninvasive arterial pressure were recorded. Cardiac output was assessed using transthoracic echocardiography. Volunteers were studied in three successive positions: baseline (semirecumbent position); after PLR of 45 degrees with the trunk lowered in the supine position; and back in the semirecubent position.ResultsWe observed significant changes in cardiac output and PVI during changes in body position. In particular, PVI decreased significantly from baseline to PLR (from 21.5 +/- 8.0% to 18.3 +/- 9.4%; P < 0.05) and increased significantly from PLR to the semirecumbent position (from 18.3 +/- 9.4% to 25.4 +/- 10.6 %; P < 0.05). A threshold PVI value above 19% was a weak but significant predictor of response to PLR (sensitivity 82%, specificity 57%, area under the receiver operating characteristic curve 0.734 +/- 0.101).ConclusionPVI can detect haemodynamic changes induced by PLR in spontaneously breathing volunteers. However, we found that PVI was a weak predictor of fluid responsiveness in this setting

Management of Metformin-Associated Lactic Acidosis by Continuous Renal Replacement Therapy

Background: Metformin-associated lactic acidosis (MALA) is a severe metabolic failure with high related mortality. Although its use is controversial, intermittent hemodialysis is reported to be the most frequently used treatment in conjunction with nonspecific supportive measures. Our aim was to report the evolution and outcome of cases managed by continuous renal replacement therapy (CRRT). Methodology and Principal Findings: Over a 3-year period, we retrospectively identified patients admitted to the intensive care unit for severe lactic acidosis caused by metformin. We included patients in our study who were treated with CRRT because of shock. We describe their clinical and biological features at admission and during renal support, as well as their evolution. We enrolled six patients with severe lactic acidosis; the mean pH and mean lactate was 6.9260.20 and 14.465.1 mmol/l, respectively. Patients had high illness severity scores, including the Simplified Acute Physiology Score II (SAPS II) (average score 63612 points). Early CRRT comprised either venovenous hemofiltration (n = 3) or hemodiafiltration (n = 3) with a mean effluent flow rate of 3466 ml/kg/h. Metabolic acidosis control and metformin elimination was rapid and there was no rebound. Outcome was favorable in all cases. Conclusions and Significance: Standard use of CRRT efficiently treated MALA in association with symptomatic orga

Illness severity.

<p>SOFA, Sequential-related Organ Failure Assessment; SAPS II, Simplified Acute Physiology Score II.</p

Acidosis, lactate and metformin levels under continuous renal replacement therapy.

<p>Panel A: Data from all patients, expressed as mean ± SD, showing that metabolic acidosis, as well as the excessive dose of metformin observed at admission (day 1, D1), were dramatically reduced from day 2 (D2). * p<0.01 versus D1. Panel B: Typical evolution in case patient 1 of both metformin plasma concentrations and metabolic disorders, which were controlled within 2 days of initiating continuous venovenous hemofiltration (CVVH), i.e. without dialysate.</p

Continuous renal replacement therapy and outcomes.

<p>CVVH, continuous venovenous hemofiltration; CVVHDF, continuous venovenous hemodiafiltration.</p

Ability of the third-generation FloTrac/Vigileo software to track changes in cardiac output in cardiac surgery patients: a polar plot approach.

International audienceOBJECTIVE: To evaluate the ability of the third-generation (3.01) of FloTrac/Vigileo monitor (Edwards Lifesciences, Irvine, CA) to follow variations in cardiac output (∆CO) using the new polar plot approach. DESIGN: Prospective interventional study. SETTING: Single hospital university study. PARTICIPANTS: Twenty-five patients referred for cardiac surgery. INTERVENTIONS: CO was measured simultaneously by 3 to 5 bolus thermodilution (COtd measurements), using a pulmonary artery catheter and by arterial pulse contour analysis, using the FloTrac/Vigileo (COvi). Data were collected at eight time points: before incision, after sternotomy, before and after protamine sulfate infusion, at the start of sternal closure, at the end of surgery, on arrival to intensive care unit, and after a standardized volume expansion with 500 mL of hetastarch 6%. MEASUREMENTS AND MAIN RESULTS: One-hundred thirty-five pairs of CO data were collected; the mean bias of all CO measurements corrected for repeated measures was 0.2 L/min with limits of agreements of -3.3 L/min and +2.9 L/min. The percentage error was 66.5%. The polar plot analysis included 71 significant ∆CO and showed a mean polar angle of -3.4 degrees with 95% polar percentage error equivalent limits of -61 to 55; 69% of analysed data points fell within the 30-degree limits and provided a correct polar concordance rate. CONCLUSIONS: Third-generation FloTrac/Vigileo software still lacks the accuracy to reliably detect changes in cardiac output (∆CO) in cardiac surgery. Improvements to FloTrac/Vigileo CO algorithm and software still are needed in this particular setting