16 Nov 09
Posted in Glucose control, Monitoring at 4:00 by Laci
By I Meynaar, M van Spreuwel, P Tangkau, L Dawson, S Visser, L Rijks, T Vlieland
Crit Care Med 2009; 37:2691-2696
To evaluate the accuracy of the AccuChek Inform point-of-care glucose measurement device as compared with central laboratory glucose measurement.
Design
Prospective, observational study.
Setting
A ten-bed mixed closed format intensive care unit in a 500-bed general hospital. The unit has a computerized insulin protocol aiming for 81 to 135 mg/dL.
Patients
All intensive care unit patients were eligible.
Interventions
None.
Measurements and main results
Paired samples (AccuChek glucose in whole blood calibrated to give whole blood results and central laboratory glucose in serum) were taken simultaneously. In 32 critically ill patients, we obtained the following information: mean ± standard deviation age 71.6 ± 11.9 yrs; mean Acute Physiology and Chronic Health Evaluation II score at admission 17.8 ± 6.7; 239 paired samples were taken from arterial catheters. Mean AccuChek whole blood glucose was 126 ± 36 mg/dL (7.0 ± 2.0 mmol/L); mean central laboratory serum glucose was 137 ± 38 mg/dL (7.6 ± 2.1 mmol/L). Mean difference was 11 mg/dL (0.61 mmol/L) (8%) (95% Confidence Interval = 9-13 mg/dL, p < .001). ISO 15197 guideline requires 95% of point-of-care measurements to be within 15 mg/dL margins with reference <75 mg/dL or within 20% if reference is higher. In total, 216 (90.4%) of AccuChek measurements were within ISO 15197 margins. Because AccuChek was calibrated to give whole blood results, we calculated a correction factor of 1.086 from the two mean values to correct whole blood AccuChek into serum-like results. This is almost the same as the correction factor of 1.080 given by Roche Diagnostics. By multiplying AccuChek whole blood results with 1.086, 225 (94.1%) of results were within the ISO 15197 margins. Hematocrit did not influence AccuChek results in the 0.20 to 0.44 range. Beyond this range, there were not enough data to draw conclusions.
Conclusions
In critically ill patients, the accuracy of AccuChek glucose measurement calibrated to give serum-like results with blood samples derived from arterial catheters is acceptable but falls short by about 1% of complying with the ISO 15197 guideline.
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03 Nov 09
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.
Methods
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.
Results
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%).
Conclusions
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.
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27 Oct 09
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.
Methods
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.
Results
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).
Conclusions
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.
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02 Sep 09
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.
Methods
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.
Results
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.
Conclusions
This study showed that the NICOM and Vigileo devices have similar monitoring capabilities in post-operative cardiac surgery patients.
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