Effect of solute temperature in the measurement of cardiac output in children using the thermodilution technique

Objectives The primary aim of this study was to compare thermodilution (TD) cardiac index (TDCi) measured by injecting cold saline (C-TDCi) to saline at room temperature (R-TDCi). The secondary aim was to assess the change in body temperature with cold saline injections in children. Design This is a prospective, case control study. Setting Cardiac catheterization lab at Le Bonheur Children's Hospital, Memphis, Tennessee. Patients Eighty-six children ≤18 years of age that underwent cardiac catheterization between April 2013 and April 2015, excluding patients with admixing lesions, on inotropic support and with ejection fraction < 30%. Interventions A TD catheter in the main pulmonary artery was used to measure cardiac output (CO). Each patient received manual injections of saline at room temperature followed by cold saline to calculate the CO. Outcome Measures CO by C-TDCi, R-TDCi, and Fick-Ci were compared using four different statistical methods. Results R-TDCi and Fick-Ci had a strong linear correlation (rho = 0.91 and 0.77, respectively; P  2 years (P > 0.05). Conclusions Cardiac indexes determined by Fick, C-TDCi, and R-TDCi were equivalent in children. Saline at room temperature can be used as an alternative to cold saline to avoid potential drop in body temperature of these patients.