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lose monitoring of the peripheral circulation is critical for the management of intensive care unit (ICU) patients, including particularly those who have just had open-heart surgery. Although peripheral temperature monitoring of the extremities is a simple method to diagnose peripheral circulatory disturbance, it does not provide a quantitative assessment. The systemic vascular resistance (SVR) index (SVRI) is an objective and standard measure of the peripheral circulation, but calculation of SVRI requires the determination of cardiac output (CO; in L/min) through invasive examination or the use of sophisticated equipment. CO is estimated non-invasively from oxygen uptake during exercise, 1 but the calculation of SVR needs central venous pressure (CVP: in mmHg) or mean right atrial pressure measurements. 2 Therefore, the development of a quantitative method to evaluate peripheral circulatory disturbance non-invasively is important.Resistive index (RI) is a parameter that not only indicates the absolute value of blood flow velocity but also reflects changes in Doppler waveforms. In the urology field, RI is used in the evaluation of the severity of impaired blood circulation following renal transplantation and progressive nephropathy. However, RI has mainly been used for evaluating blood flow to a target organ, but not for hemodynamics. In patients with extreme hemodynamics, including those who have had open-heart surgery and following an emergency, it is very important to know the impairment of the peripheral circulation; therefore, if RI could be used simply to quantify systemic blood vessel resistance, it could be an important parameter for circulation control, based on a different perspective from that of cardiac output and oxygen saturation of mixed-venous blood. Here, we measured RI in the upper extremity arteries, examined the most effective point of measurement, and determined whether this technique allows for the quantitative evaluation of peripheral circulatory disturbance. Methods Measurements of RIAt each measurement point, a 7.5 MHz probe was positioned on the measurement surface and a target artery (simulated peripheral artery in vitro) was imaged in B mode. A site with the minimum ultrasonic incidence angle was selected in the artery on display and pulsed Doppler ultrasonography was conducted. The systolic maximum velocity (Vmax) and diastolic minimum velocity (Vmin) of the pulsed Doppler waveforms were determined and Background To explore an alternative to the systemic vascular resistance index (SVRI) for monitoring peripheral circulation in patients in the intensive care unit (ICU), the resistive index (RI) in the upper extremity arteries was measured by using surface Doppler ultrasound. Methods and ResultsThe correlation between RI and vascular resistance was assessed in vitro using a vessel phantom in a Donovan-type mock circulation system. In addition, 15 ICU patients who had undergone open-heart surgery were studied. Mean arterial pressure, central venous pressure and cardiac output were measu...

Radial artery (RA) harvesting for coronary artery bypass may lead to ischemia of the digits if the collateral hand circulation is inadequate. 1 Although Allen's test is a subjective method with a high possibility of false negative and positive results, it is the most commonly used screening method to evaluate the adequacy of collateral hand circulation before RA harvesting for coronary artery bypass grafting. 2,3 To develop more objective methods than Allen's test, we studied hand circulation with RA compression using a 7.5 MHz color Doppler study and monitoring of pressure in the digits.Methods and results. The subjects were 10 healthy surgical residents in whom Allen's test yielded negative results (9 men and 1 woman, aged 25 to 39 years). The Doppler signals of the RA in the anatomic snuff-box were measured with RA compression in the color Doppler mode of a 7.5 MHz echocardiographic system (PLF-703NT, Sonolayer SSA-260A, Toshiba, Tokyo, Japan). The probe was placed next to the snuff-box. The insonation angle was corrected to less than 15°to visualize the optimal Doppler flow. Digital artery systolic pressure with RA compression was measured with a commercially available blood pressure monitor (HEM-808 F, Omron Co, Tokyo, Japan). The Wilcoxon signed-rank test was used for the statistical analysis. Color Doppler study revealed that the direction of the flow was backward in all hands with RA compression. Thus the Doppler signals away

Percutaneous cardiopulmonary support (PCPS) has come to be applied for cardiopulmonary resuscitation and in the management of severe respiratory failure as well as severe heart failure. We investigated cerebral tissue oxygen saturation during PCPS in a canine model of respiratory failure using near-infrared spectroscopy. Animals were mechanically ventilated with 10% oxygen to make a respiratory failure model. Perfusion with PCPS was performed via the left femoral artery and switched to that via the right axillary artery. Cerebral tissue oxygen saturation was 54.2 +/- 3.4% during PCPS via the femoral artery and was 82.3 +/- 4.6% during PCPS via the axillary artery (p = 0.001). Hepatic tissue oxygen saturation was not significantly different. LV dP/dt max increased significantly after switching to the axillary blood supply (p = 0.001). Conventional PCPS may not have the capability of supporting cerebral circulation under severe respiratory failure without organic heart disease.

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