ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
-
Comparative Study
Validation of a novel ultrasound dilution method to measure cardiac output during hemodialysis.
A method to measure cardiac output (CO) based on ultrasound velocity dilution during hemodialysis was validated in an animal model against direct measurement using a transit time technique and a calibrated pump. In two anesthetized pigs, a 20 mm transit time ultrasound flow probe was placed on the ascending aorta to measure CO, and the right femoral artery and vein were cannulated for hemodialysis access. The dual sensor HD01 Hemodialysis Monitor was positioned on the arterial and venous tubing lines for measurement of cardiac output by ultrasound velocity dilution (COUD) by intravenous injections of 10-20 ml isotonic saline at 37 degrees C. ⋯ The COUD (n = 9) was compared with cardiac output as measured by pump flow (COP). A linear relationship was observed between COUD and COT (COUD) = 0.948 x COT + 0.086 L/min, r = 0.95), and between COUD and COP (COUD = 1.06 x COP-0.327 L/min, r = 0.99). Thus, cardiac output measured by ultrasound velocity dilution during hemodialysis is in good agreement with well established, but invasive, transit time and pump standards.
-
The authors analyzed factors that may influence the outcome of adult patients with respiratory failure who were treated with ECMO. Between December 1990 and July 1995, the authors used ECMO to support 33 patients (age range, 17-56 years) with respiratory failure from adult respiratory distress syndrome (ARDS; n = 9), primary graft failure after lung transplantation (n = 16), late graft failure after lung transplantation (n = 5), and miscellaneous reasons (n = 3). Twenty (61%) patients were successfully weaned from ECMO, and 13 (39%) survived to hospital discharge. ⋯ Compared with the nonsurvivors, survivors had higher PF ratios (PaO2/FIO2; 104 +/- 33 vs 81 +/- 8, p = 0.43) before ECMO was initiated, although the differences were not significant. Among the patients who received ECMO for primary graft failure, 75% were weaned from ECMO, and 56% survived to discharge. ECMO is beneficial for adult patients with respiratory failure, especially those with primary graft failure after lung transplantation.
-
Comparative Study
Determinants of clinical results of mechanical circulatory support for ventricular failure after cardiotomy.
To clarify determinants of clinical results of circulatory support for ventricular failure after cardiotomy, we examined 53 patients (33 men and 20 women) who underwent circulatory support for post operative heart failure from 1984 to October 1995. Their ages ranged from 22 to 74 years (mean, 51 years). In 53 patients, 32 had valvular, 19 had ischemic, and 2 had congenital heart disease. ⋯ Peri-operative variables before and during circulatory support were analyzed multivariately by logistic regression analysis. Selected independent determinants (odds ratio) of significant difference (p < .05) were type of support (7.547) for non weaning and pre support cardiogenic shock (17.246), and type of support (8.780) and support duration (1.487) for mortality. These results suggest that early application before profound shock and appropriate selection of type of support might be key factors in successful circulatory support for ventricular failure occurring after cardiotomy.
-
Comparative Study
Validation of a new method to measure cardiac output during extracorporeal detoxification.
Cardiac output was measured in 11 patients during extra-corporeal detoxification after open heart surgery. All patients were mechanically ventilated and had pulmonary artery catheters for cardiac output (COT) measured by thermodilution. A sensor on the arterial side of the extracorporeal circulation measured flow and sound velocity transients. ⋯ The regression equation was COUD = 1.09 x COT-0.32 (r = 0.97, n = 31). These data suggest agreement between the ultrasound dilution technique and thermodilution. Ultrasound dilution is preferable in patients undergoing extracorporeal detoxification when pulmonary artery catheterization is not required or dangerous.
-
Comparative Study
Hemodialysis access flow measurement. Comparison of ultrasound dilution and duplex ultrasonography.
Decreased hemodialysis access flow is associated with an increased risk of access thrombosis. Duplex ultrasonography can measure access flow and select a subset of patients at increased risk for access failure. With in-line techniques (ultrasound dilution), access flow can be measured during hemodialysis. ⋯ Regression analysis revealed a linear relationship between the two techniques described by the equation QAT = 246.14 + 0.8104(QAS) (correlation coefficient of 0.83; p < 0.0001). Measurement of hemodialysis access flow by ultrasound dilution was essentially equivalent to that obtained by duplex ultrasound. Additional studies are needed to determine if regular in-line flow measurements can predict and prevent future access thrombosis and decreased the cost of access management.