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This study compares the correlation between two methods for the determination of cardiac output-the pulmonary arterial thermodilution technique using the Swan-Ganz catheter and the femoral arterial thermodilution technique using a pulse contour analysis computer (PiCCO) catheter. We performed a prospective animal study using 16 immature Maryland pigs weighing 9 to 16 kg. A 5.5- or 7.5-Fr Swan-Ganz catheter was introduced into the femoral or jugular vein, and a 4- or 5-Fr arterial PiCCO catheter was introduced into the femoral artery. In each animal, we made measurements of cardiac output at 30-minute intervals, simultaneously by pulmonary arterial thermodilution and femoral arterial thermodilution, before, during, and after hemodiafiltration carried out via different venous catheters, recording a total of 78 measurements. The mean Swan-Ganz cardiac output was 2.22 +/- 0.94 L/min, and mean PiCCO cardiac output was 1.94 +/- 0.80 L/min (no significant difference). The mean difference (bias) of differences (limits of agreement) was 0.2812. The differences between the methods increased with higher cardiac output, but the percentage differences in relation to cardiac output remained stable. Good correlation was found between the two methods: single-measure intraclass correlation was 0.8892 (95% confidence interval, 0.54-0.95). There were no differences between the 5.5- and 7.5-FR Swan-Ganz catheters or between the 4- and 5-Fr PiCCO catheters. Femoral arterial thermodilution cardiac output measurements correlated well with pulmonary arterial thermodilution cardiac output measurements in a pediatric animal model.

Intrathoracic and intracardiac volume values obtained by arterial thermodilution are lower than those considered normal in the adult, whereas the extravascular lung water is higher. These values must be taken into account when the PiCCO method is used in small children.

Background Therapeutic drug monitoring (TDM) of adalimumab (ADA) in inflammatory bowel diseases (IBDs) has gained increased attention since several studies showed a correlation between drug levels and mucosal healing. The limitations of routine usage of enzyme-linked immunoabsorbent assay (ELISA) kits for measuring serum ADA concentrations have prompted the development of rapid methods, such as Quantum Blue (QB). We evaluated the interchangeability and agreement between the QB method and two established ELISA kits, Promonitor (PM) and Lisa-Tracker (LT). Methods Fifty samples from patients with IBD were included. Quantitative analysis was performed using the ANOVA test for repeated measures, Deming regression and the Bland-Altman plot. Clinical implications were evaluated by concordance in classifying patients into therapeutic windows according to the proposed cut-off levels for subtherapeutic (either <5 or <7.5 μg/mL) and supratherapeutic (>12 μg/mL) ranges. Results Statistical differences were detected between the QB method and the two ELISA kits, with QB overestimating ADA serum values compared to them. A lack of interchangeability was observed between methods, with greater differences as ADA levels increased. An analysis of a sub-set of samples with ADA values below 9 μg/mL (n = 25) showed that QB fulfilled the criteria to be interchangeable with the LT assay. Concordance for patient classification into ADA therapeutic windows was better for QB vs. LT than for QB vs. PM, with high agreement (>75%) for subtherapeutic levels among the three methods. Conclusions Although quantitative differences existed between the rapid method and ELISA kits that hampered their interchangeability, the agreement for identifying patients with subtherapeutic values of ADA was high.