03 Nov 09

Evaluation of stroke volume variation obtained by arterial pulse contour analysis to predict fluid responsiveness intraoperatively

Posted in Fluid management, Monitoring at 2:27 by Laci

By D Lahner, B Kabon, C Marschalek, A Chiari, G Pestel, A Kaider, E Fleischmann and H Hetz

Br. J. Anaesth. 2009 103: 346-351

Fluid management guided by oesophageal Doppler monitor has been reported to improve perioperative outcome. Stroke volume variation (SVV) is considered a reliable clinical predictor of fluid responsiveness. Consequently, the aim of the present trial was to evaluate the accuracy of SVV determined by arterial pulse contour (APCO) analysis, using the FloTracTM/VigileoTM system, to predict fluid responsiveness as measured by the oesophageal Doppler.

Patients undergoing major abdominal surgery received intraoperative fluid management guided by oesophageal Doppler monitoring. Fluid boluses of 250 ml each were administered in case of a decrease in corrected flow time (FTc) to <350 ms. Patients were connected to a monitoring device, obtaining SVV by APCO. Haemodynamic variables were recorded before and after fluid bolus application. Fluid responsiveness was defined as an increase in stroke volume index >10%. The ability of SVV to predict fluid responsiveness was assessed by calculation of the area under the receiver operating characteristic (ROC) curve.

Twenty patients received 67 fluid boluses. Fifty-two of the 67 fluid boluses administered resulted in fluid responsiveness. SVV achieved an area under the ROC curve of 0.512 [confidence interval (CI) 0.32–0.70]. A cut-off point for fluid responsiveness was found for SVV > 8.5% (sensitivity: 77%; specificity: 43%; positive predictive value: 84%; and negative predictive value: 33%).

This prospective, interventional observer-blinded study demonstrates that SVV obtained by APCO, using the FloTracTM/VigileoTM system, is not a reliable predictor of fluid responsiveness in the setting of major abdominal surgery.

27 Oct 09

Hemodynamic variables and mortality in cardiogenic shock

Posted in Heart failure/Cardiogenic shock, Monitoring at 0:01 by Laci

By C Torgersen, C Schmittinger, S Wagne, H Ulmer, J Takala, S Jakob and M Dunser

Critical Care 2009,13:R157

Despite the key role of hemodynamic goals, there are few data addressing the question as to which hemodynamic variables are associated with outcome or should be targeted in cardiogenic shock patients. The aim of this study was to investigate the association between hemodynamic variables and cardiogenic shock mortality.

Medical records and the patient data management system of a multidisciplinary intensive care unit (ICU) were reviewed for patients admitted because of cardiogenic shock. In all patients, the hourly variable time integral of hemodynamic variables during the first 24 hours after ICU admission was calculated. If hemodynamic variables were associated with 28-day mortality, the hourly variable time integral of drops below clinically relevant threshold levels was computed. Regression models and receiver operator characteristic analyses were calculated. All statistical models were adjusted for age, admission year, mean catecholamine doses and the Simplified Acute Physiology Score II (excluding hemodynamic counts) in order to account for the influence of age, changes in therapies during the observation period, the severity of cardiovascular failure and the severity of the underlying disease on 28-day mortality.

One-hundred-nineteen patients were included. Cardiac index (CI) (P=0.01) and cardiac power index (CPI) (P=0.03) were the only hemodynamic variables separately associated with mortality. The hourly time integral of CI drops <3, 2.75 (both P=0.02) and 2.5 (P=0.03) L/min/m2 was associated with death but not that of CI drops <2 L/min/m2 or lower thresholds (all P>0.05). The hourly time integral of CPI drops <0.5-0.8 W/m2 (all P=0.04) was associated with 28-day mortality but not that of CPI drops <0.4 W/m2 or lower thresholds (all P>0.05).

During the first 24 hours after intensive care unit admission, CI and CPI are the most important hemodynamic variables separately associated with 28-day mortality in patients with cardiogenic shock. A CI of 3 L/min/m^2 and a CPI of 0.8 W/m2 were most predictive of 28-day mortality. Since our results must be considered hypothesis-generating, randomized controlled trials are required to evaluate whether targeting these levels as early resuscitation endpoints can improve mortality in cardiogenic shock.

02 Sep 09

Comparison between Flotrac-Vigileo and Bioreactance, a totally noninvasive method for cardiac output monitoring

Posted in Monitoring at 0:01 by Laci

By S Marqué, A Cariou, J-D Chiche and Pierre Squara

Critical Care 2009, 13:R73

This study was designed to compare the clinical acceptability of two cardiac output (CO) monitoring systems: a pulse wave contour-based system (FloTrac-Vigileo) and a bioreactance-based system (NICOM), using continuous thermodilution (PAC-CCO) as a reference method.

Consecutive patients, requiring PAC-CCO monitoring following cardiac surgery, were also monitored by the two other devices. CO values obtained simultaneously by the three systems were recorded continuously on a minute-by-minute basis.

Continuous recording was performed on 29 patients, providing 12,099 simultaneous measurements for each device (417 ± 107 per patient). In stable conditions, correlations of NICOM and Vigileo with PAC-CCO were 0.77 and 0.69, respectively. The bias was -0.01 ± 0.84 for NICOM and -0.01 ± 0.81 for Vigileo (NS). NICOM relative error was less than 30% in 94% of the patients and less than 20% in 79% vs. 91% and 79% for the Vigileo, respectively (NS). The variability of measurements around the trend line (precision) was not different between the three methods: 8 ± 3%, 8 ± 4% and 8 ± 3% for PAC-CCO, NICOM and Vigileo, respectively. CO changes were 7.2 minutes faster with Vigileo and 6.9 minutes faster with NICOM (P < 0.05 both systems vs. PAC-CCO, NS). Amplitude of changes was not significantly different than thermodilution. Finally, the sensitivity and specificity for predicting significant CO changes were 0.91 and 0.95 respectively for the NICOM and 0.86 and 0.92 respectively for the Vigileo.

This study showed that the NICOM and Vigileo devices have similar monitoring capabilities in post-operative cardiac surgery patients.

18 Apr 09

Gastric tonometry versus cardiac index as resuscitation goals in septic shock: a multicenter, randomized, controlled trial

Posted in Monitoring, Sepsis at 8:00 by Laci

By F Palizas, A Dubin, T Regueira, A Bruhn, E Knobel, S Lazzeri, N Baredes and G Hernandez

Critical Care 2009, 13:R44

The goals for septic shock resuscitation remain controversial. Despite the normalization of systemic hemodynamic variables, tissue hypoperfusion can still persist. Indeed, lactate or oxygen venous saturation may be difficult to interpret. Our hypothesis was that a gastric intramucosal pH-guided resuscitation protocol might improve the outcome of septic shock compared to a standard approach aimed at normalizing systemic parameters such as cardiac index (CI).

130 septic shock patients were randomized to two different resuscitation goals: CI greater than or equal to 3.0 L/min/m2 (CI group: 66 patients) or intramucosal pH (pHi) greater than or equal to 7.32 (pHi group: 64 patients). After correcting basic physiologic parameters, additional resuscitation consisting in more fluids and dobutamine was started if specific goals for each group had not been reached. Several clinical data were registered at baseline and during evolution. Hemodynamic data and pHi values were registered every 6 hours during the protocol. Primary end-point was 28 days mortality.

Both groups were comparable at baseline. The most frequent sources of infection were abdominal sepsis and pneumonia. Twenty-eight day mortality (30.3 vs. 28.1%), peak Therapeutic Intervention Scoring System scores (32.6 +/- 6.5 vs. 33.2 +/- 4.7) and ICU length of stay (12.6 +/- 8.2 vs. 16 +/- 12.4 days) were comparable. A higher proportion of patients exhibited values below the specific target at baseline in the pHi group compared to the CI group (50% vs. 10.9%; P < 0.001). Of 32 patients with a pHi < 7.32 at baseline, only 7 (22%) normalized this parameter after resuscitation. Areas under the receiver operator characteristic curves to predict mortality at baseline, and at 24 and 48 hours were 0.55, 0.61, and 0.47, and 0.70, 0.90, and 0.75, for CI and pHi, respectively.

Our study failed to demonstrate any survival benefit of using pHi compared to CI as resuscitation goal in septic shock patients. Nevertheless, a normalization of pHi within 24 hours of resuscitation is a strong signal of therapeutic success and in contrast, a persistent low pHi despite treatment is associated with a very bad prognosis in septic shock patients.

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