A simple method for Emax trend evaluation: in vitro and in vivo results.

The aim of this study is the evaluation of end systolic ventricular elastance trend (as a measure of heart contractility) by hemodynamic variables available in intensive care units or during heart surgery: heart rate, cardiac output, left atrial, mean and diastolic arterial pressure. Its basic assumption is the description of ejection as the interaction between variable left ventricular and arterial compliances (reciprocal of the corresponding elastances) connected in parallel. As pressure is the same in each compliance at systole beginning and ending, ventricular elastance can be estimated by assuming that energy variation is the same on both compliances. The algorithm has been tested on a numerical simulator of the circulatory system and on six sheep at basal conditions and during drug infusion. Correlation function in numerical simulation, between true and computed ventricular elastance (range 0.45 divided by 5 mm Hg-cm(-3)), yields 0.985. In vivo comparison between computed ventricular elastance trend and ventricular dp/dt trend yields a correlation function ranging between 0.87 and 0.99. The result of the algorithm cannot be assumed to be Emax value. However, it can be considered a contractility index as it closely follows any change in dp/dt. It can be computed by simple calculations and needs no variables other than those usually measured in intensive care . It allows the extrapolation of useful information for evaluating the trend in heart contractility and for setting up a control strategy for mechanical or pharmacological assistance during heart recovery.

Cardiopulmonary bypass in pregnancy.

The cardiopathic patient can sustain acute heart failure during pregnancy. In such cases, if open heart operation is necessary to save the patient's life, the fetus could be seriously compromised after exposure to cardiopulmonary bypass. From 1958 to 1992, 69 reports of cardiac operations during pregnancy with the aid of cardiopulmonary bypass have been published. Maternal mortality was 2.9%. Embryofetal mortality was 20.2%. Examining only the last 40 patients, maternal and embryofetal mortality were 0.0% and 12.5%, respectively. Embryofetal mortality was 24.0% when hypothermia was used, compared with 0.0% while operating in normothermia. Maternal mortality did not change. The use of hypothermia during cardiopulmonary bypass provoked uterine contractions in several patients. Hypothermia decreases O2 exchange through the placenta. Pump flow and mean arterial pressure during cardiopulmonary bypass seem to be the most important parameters that influence fetal oxygenation. We speculate that cardiac operation is not a contraindication to pregnancy prolongation.

"Mold-like" calcification of the left atrium and of the pulmonary veins. Total endoatriectomy in a patient undergoing mitral valve replacement.

Mold-like left atrial calcification is a rare aspect of rheumatic mitral valvular disease. Its interest lies in the difficulty of surgical technique during interventions for valvular substitution. This is a case report in which the total excision of the calcified mold by a wide endoatriectomy was necessary in order to substitute the stenotic mitral valve.

[Routine clinical use of a new disposable bubble oxygenator: a comparative study (author's transl)]. / Impiego clinico rutinario di un nuovo ossigenatore a bolle monouso. Una valutazione comparativa.

The new bubble Oxybel oxygenator (Bellco Laboratories) has been used for routine clinical perfusions in this Institution. A comparison has been made between two groups of 51 patients each, one group perfused with on Oxybel oxygenator (OXY) and the other with the Harvey H 1000 oxygenator (H-H). Among these patients a wide range of acquired and congenital cardiac lesions have been encountered. Both series were comparable for patients' age, sex distribution, body weight, procedures performed, perfusion time and preoperative values of hematocrit, serum creatinine, platelet count, plasma hemoglobin. The gas/blood flow ratio was 2.09 +/- 0.07 (+/- SE) for the H-H oxygenator and 1.38 +/- 0.06 for the OXY series (P < 0.001). Serum-creatinine 24-hrs postoperative values (mg/100 ml) were 1.58 +/- 0.17 for the H-H and 1.30 +/- 0.06 for the OXY series (NS); 48-hrs postoperative values were 1.28 +/- 0.11 for the H-H and 1.20 +/- 0.11 for the OXY (NS). The 60 minutes postoperative platelet count was 127.9 +/- 7 X 10(3) for the H-H and 120.9 +/- 6 X 10(3) for the OXY series (NS). Fourtyeight-hrs postoperative platelet count was 153.0 +/- 5 X 10(3) for the H-H and 151.8 +/- 6 X 10(3) for the OXY series (NS). Postoperative plasma hemoglobin values (mg/100 ml) were 91.55 +/- 7.18 for H-H and 117 +/- 17.8 for the OXY series (NS). Total postoperative bleeding was 1037.9 +/- 94 ml in the H-H and 1056.7 +/- 98.9 ml in the OXY series (NS). The more favorable gas/blood flow ratio observed with the Oxybel oxygenator did not affect clinical and haematologic results. These were comparable in both series.