To compare the accuracy of an integrated fiberoptic monitoring system using transpulmonary thermo-dye dilution technique to measure blood volume (BV) with standard method using chromium-51-tagged erythrocytes in septic shock.Design:
Prospective blinded animal laboratory study.Setting:
University department of anesthesiology.Subjects:
Thirty-five anesthetized and mechanically ventilated pigs (21.4 ± 2.2 kg) were investigated over a period of 6 hrs.Interventions:
Septic shock was induced with fecal peritonitis (0.75 g · kg−1 per body weight autologous feces). A central venous catheter was used for injection of the indicator dyes.Measurements and Main Results:
BV was measured by detecting indocyanine green using a 4-Fr aortic catheter with an integrated fiberoptic and thermistor connected to a computer system for calculation of transpulmonary indicator dilution BV (BVTPID). 51Cr-tagged erythrocytes were used as standard method of BV measurement (BV-51Cr). Hemodynamic treatment scheme was aimed at maintenance of a central venous pressure of 12 mm Hg. Data were analyzed using Bland-Altman analyses. One hundred and five data pairs of simultaneous BV measurements were yielded during hemodynamic stability with a mean BVTPID of 64.2 ± 17.8 mL · kg−1. Mean BV-51Cr was 83.1 ± 17.0 mL · kg−1. Linear regression equation was BVTPID = 0.58 × BV-51Cr + 15.8 (r = .56, p < .01). Mean bias was 18.9 mL · kg−1 (95% confidence interval, 15.7–22.1 mL · kg−1), with limits of agreement of −13.9 to 51.7 mL · kg−1.Conclusions:
Transpulmonary indicator dilution for blood volume measurement agrees moderately with standard method using 51Cr-tagged erythrocytes in porcine septic shock.