Carotid Doppler microembolic signals in patients one year after heart valve surgery.

Doppler ultrasound has been used to detect microemboli during and after cardiopulmonary bypass (CPB). The aim of the present study was to examine the frequency of microembolic signals (MES) in patients one year after heart valve replacement, to look for possible risk factors associated with MES and for any correlation with cerebral events. One hundred patients, 69 male and 31 female, mean age 66.

Comparison of bubble release from various types of oxygenators. An in vivo investigation.

The present study compares the creation of free gas bubbles in five different bubble oxygenators and one membrane oxygenator, by use of Doppler ultrasound technique. The study was carried out on groups of male patients undergoing coronary artery bypass surgery. The results show that the bubble oxygenators produce a considerable amount of free gas bubbles, with variances based on type.

Gas bubble detection in fluid lines by means of pulsed Doppler ultrasound.

A pulsed Doppler instrument running at 1.5 MHz resonance frequency was used for detection of microbubbles within a recirculating fluid line. Glass beads of nominal 200 microns were injected to get a statistical calibration level of the set-up.

Comparison of bubble release from various types of oxygenators.

A comparative study of microbubble release from various types of oxygenators was performed using ultrasonic Doppler techniques. Bubble count versus amplitude histograms were calculated to derive the statistical distribution of the relative microbubble sizes. To compare the different oxygenators with respect to differences in microbubble releases, several key parameters as, temperature, liquid flow rate, gas to flow relationship, liquid level within the oxygenator, were altered one at a time to indicate different and oxygenator related sensitivities with respect to variations of the key parameters.

Assessment of prosthetic mitral valve pressure gradients by means of ultrasound Doppler technique and on-line spectral analysis.

The blood speed through prosthetic mitral valves was determined using ultrasound Doppler techniques combined with on-line spectral analysis. Spectral analysis was particularly suitable for maximum velocity estimation due to its superior ability in discriminating between Doppler signals and white background noise. From a simplified Bernoulli equation the corresponding transprosthetic pressure drop was calculated and estimates were compared against pressure gradients obtained by conventional intracardiac catheterization.

The value of activated coagulation time in monitoring heparin therapy during extracorporeal circulation.

The anticoagulant effect of heparin was studied in 20 patients undergoing aortocoronary bypass surgery. The protamine dose necessary to reverse heparin after extracorporeal circulation (ECC) was assessed in ten patients from individual heparin dose-response curves (HDR group). The other ten patients received protamine according to a routine protocol (control group).

Haemodynamic changes with the administration of nitrous oxide during coronary artery surgery.

Haemodynamic responses to 50% nitrous oxide in oxygen during coronary artery surgery were investigated in 10 patients. Morphine, diazepam and pancuronium were given intravenously as both induction and maintenance anaesthesia. A significant decrease was seen in heart rate, arterial pressure, pulmonary artery pressure, heart rate-systolic arterial pressure product, peripheral vascular resistance, left ventricular end-diastolic pressure, dP/dT of the left ventricle and resistance as measured in the graft to the left anterior descending coronary artery (LAD).

Cyst of seminal vesicle associated with ipsilateral renal agenesis. A report on four cases.

Four cases of seminal vesicle cyst associated with agenesis of the ipsilateral kidney are presented. The literature and the embryologic development of this rare anomaly are briefly surveyed.