Continuous on-line glucose measurement by microdialysis in a central vein. A pilot study

Abstract

IntroductionTight glucose control in the ICU has been proven difficult with an increased risk for hypoglycaemic episodes. Also the variability of glucose may have an impact on morbidity. An accurate and feasible on-line/continuous measurement is therefore desired. In this study a central vein catheter with a microdialysis membrane in combination with an on-line analyzer for continuous monitoring of circulating glucose and lactate by the central route was tested.MethodsA total of 10 patients scheduled for major upper abdominal surgery were included in this observational prospective study at a university hospital. The patients received an extra central venous catheter with a microdialysis membrane placed in the right jugular vein. Continuous microdialysis measurement proceeded for 20 hours and on-line values were recorded every minute. Reference arterial plasma glucose and blood lactate samples were collected every hour.ResultsMean microdialysis-glucose during measurements was 9.8 ± 2.4mmol/l.No statistical difference in the readings was seen using a single calibration compared to eighth hour calibration (P =0.09; t-test). There was a close agreement between the continuous reading and the reference plasma glucose values with an absolute difference of 0.6+0.8mmol, or 6.8+9.3% and measurements showed high correlation to plasma readings (r = 0.92). Thelimit of agreement was 23.0%(1.94 mmol/l) compared to arterial plasma values with a line of equality close to zero.However, in a Clarke-Error Grid 93.3% of the values are in the A-area,and the remaining part in the B-area.Mean microdialysis-lactate was 1.3 ± 1.1mmol/l. The measurements showed high correlation to the blood readings (r = 0.93).ConclusionContinuous on-line microdialysis glucose measurement in a central vein is a potential useful technique for continuous glucose monitoring in critically ill patients, but more improvements and testingare needed.

Ex-vivo glucose sensors using micro-dialysis: importance of on-line recovery rate determination by multi-analyte infrared spectrometry

“…4 For intensive care units, different approaches have been chosen, using either subcutaneously implanted microdialysis catheters, intravascularly inserted probes or extracorporeal microdialysis with continuously sampled and heparinised whole blood, from which dialysates have been obtained. [5][6][7][8][9][10][11] The latter microdialysis technique, as described in detail by Feichtner et al,7 has also been used by us in combination with infrared spectroscopy for ex-vivo glucose quantification. 12,13 Recently, an overview for continuous glucose monitoring (CGM) systems, based on electrochemical sensing as utilised in needle-type sensors directly implanted and micro-dialysis based systems for interstitial fluid or intravascular application with ex-vivo detection, has been given by Lucarelli et al 14 .…”

Hiperglicemia por sepsis: del mecanismo a la clínica

“…Se recomienda el análisis de sangre arterial o venosa por sobre la muestra de sangre capilar debido a que las lecturas de los glucómetros capilares son inexactas en estos pacientes; sin embargo, si no se disponen de métodos de monitorización continua, siguen siendo de gran utilidad evitando retrasos en la toma de decisiones 47 . En la última década se han desarrollado nuevas técnicas de medición seriada de glicemia, tales como monitorización subcutánea continua 48 y medición online a través de un catéter venoso central con membrana de micro diálisis 49 . Esta última tiene la particularidad de no ser influida por la perfusión tisular y tendría especial importancia en la prevención de la variabilidad de los eventos de hipo-e hiperglicemia.…”

Assessment and treatment of hyperglycemia in critically ill patients

“…(38) This potentially useful technique still needs further studies to prove its utility in clinical practice.…”