17 Mar

Effects of Injection Site on the Accuracy of Thermal Washout: Methods and Materials (7)

Five milliliters of 5 percent dextrose solution in iced water was injected into RA or RV, and the temperature change was analyzed by cardiac output (CO) computer (AH611V, NihonKohden, Tokyo, Japan). The temperature of the injectate in iced water was monitored with a thermistor and used for calculation of CO by the computer. Duplicate or triplicate paired injection in the RA and RV were repeated irrespective of respiratory cycle, and four or six values were obtained at a time. Variation of the measurement in each patient was evaluated using the coefficient of variation, which was obtained by dividing the standard deviation by the mean value and multiplying by 100. antibiotic levaquin
The Model Heart: Different combinations of mechanically preset EFs (0.4, 0.44, and 0.62), stroke frequencies (60 and 100 strokes/ min), and injection sites (inflow circuit, chamber, and inflow circuit via the Swan-Ganz catheter) were examined (Table 1). The EFs and the stroke rate were preset at 0.4 or 0.62, and 60 stroke/min, respectively (preset stroke volume and CO were 60 ml or 93 ml, and 3.6 L/min or 5.6 L/min, respectively) and 10 ml of iced water was injected directly into the chamber or the inflow tract under each condition.

Table 1—Experimental Protocol in the Model Heart

Mechanically Determined Pump Conditions Injection Site of Cold Water
EF Stroke Frequency
0.4 60 RA (direct injection)RV (direct injection)RA through Swan-Ganz catheter RA (direct injection)
0.62 60 RV (direct injection)RA through Swan-Ganz catheter
0.44 100 RA (direct injection) RV (direct injection)

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