Timothy T Hamilton | PubMed Health

PubMed2005

Lung preservation solution substrate composition affects rat lung oxidative metabolism during hypothermic storage.

Lungs harvested for transplantation utilize oxygen after procurement. We investigated the effects of storage solution substrate composition on pulmonary oxidative metabolism and energetics during the preservation interval. Rat lungs were harvested and stored at 10 degrees C in low-potassium dextran (LPD) solution. Groups of lungs were preserved with preservation solution containing 5mM carbon-13 ((13)C) labeled glucose or increasing concentrations of (13)C labeled pyruvate. Additional groups of rat lungs were studied with dichloroacetate (DCA) added to the pyruvate-modified preservation solutions. Oxidative metabolism (measured by (13)C-enrichment of glutamate) and adenine nucleotide levels were quantified. Increasing preservation solution pyruvate concentration augmented glutamate (13)C-enrichment up to a concentration of 32mM pyruvate. DCA further stimulated oxidative metabolism only at lower concentrations of pyruvate (4 and 8mM). ATP and ADP were not different among groups, but AMP levels were higher in the glucose group. These data suggest that altering the substrate composition of the preservation solution influences lung metabolism during allograft preservation for transplantation.

Adenosine Triphosphate↗

PubMed2002

PulseCO: a less-invasive method to monitor cardiac output from arterial pressure after cardiac surgery.

BACKGROUND: Cardiac output is often monitored after cardiac operations with a pulmonary artery catheter. A new method has been introduced that measures cardiac output by lithium dilution (LiDCO) and uses these data to calibrate a system (PulseCO) that calculates cardiac output continuously from the energy of the arterial pressure waveform. It is unknown whether PulseCO measurements are valid early after cardiac surgery when changes in temperature and vascular tone or intermittent use of the arterial line for blood sampling may occur. This study assessed the reliability of cardiac output determinations by PulseCO in the first 8 hours after cardiac surgery. METHODS: After a one-time PulseCO calibration, cardiac output was measured in 20 patients who had undergone coronary artery bypass grafting at 0, 2, 4, 6, and 8 hours after arrival in the intensive care unit using (1) thermodilution through a pulmonary artery catheter (Thermo); (2) lithium dilution (LiDCO); and (3) PulseCO. Concordance correlations were calculated between methods, and differences were compared by Wilcoxon paired rank test and Bland-Altman analysis. RESULTS: Cardiac output ranged from 3.4 to 8.5 L/min. No significant differences were noted between measurements obtained by each technique at any time point. Concordance correlations and Bland-Altman analysis confirmed good agreement between PulseCO and Thermo determinations of cardiac output during the study interval. CONCLUSIONS: PulseCO measurements remain reliable without recalibration for at least 8 hours after cardiac surgery and may offer a less-invasive approach for early postoperative cardiac output monitoring.

Blood Pressure↗