Hormone metabolism in the pulmonary circulation.

We measured hormonal levels in blood samples from pulmonary and radial arteries in 117 patients undergoing aorto-coronary by-pass surgery with the aim of investigating the role of the pulmonary vessel endothelium in hormone metabolism. Insulin and glucagon concentrations were significantly higher in pulmonary artery blood with respect to radial artery blood (73 +/- 65 vs. 65 +/- 47 pmol/l, p < 0.005, and 80 +/- 49 vs. 73 +/- 51 ng/l, p < 0.01, respectively), while no difference was found for growth hormone, prolactin, C peptide, insulin-like growth factor I, follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, parathyroid hormone, thyroglobulin, triiodothyronine, thyroxine, free triiodothyronine, and free thyroxine. Moreover, prolactin concentrations were more than twice the normal levels, this being an effect of propafol and the opiate fentanyl used for the general anesthesia. Assuming that the arteriovenous differences observed are a marker of peptide hormone degradation, our study has demonstrated that with similar kinetics insulin and glucagon secreted into portal circulation and escaping from hepatic extraction undergo further homeostatic removal of about 9-10 % in the pulmonary circulation before entering the general circulation.

[Weaning in cardiopulmonary bypass patients with compromised cardiac function. Comparison of enoximone and dopamine]. / Weaning dal bypass cardiopolmonare di pazienti coronaropatici a funzionalità cardiaca compromessa. Confronto tra enoximone e dopamina.

OBJECTIVE: Evaluate the effects of enoximone and dopamine in patients with impaired left ventricular function after cardiopulmonary bypass (CPB). DESIGN: Prospective study on a consecutive series of patients subdivided into two groups: enoximone (Group E) and dopamine (Group D). SETTING: Policlinico Umberto I, University La Sapienza of Rome. PATIENTS AND METHODS: Thirty patients undergoing elective myocardial revascularization. Before weaning from CPB the patients received inotropic drugs as follows: Group E: enoximone: bolus: 1 mg/kg in 10 min, and continuous infusion of 5 mcg/kg/min; Gruppo D: dopamine: continuous infusion of 5 mcg/kg/min. Hemodynamic measurements were made using a Swan-Ganz catheter inserted before the induction of anaesthesia. RESULTS: Enoximone has proved to be effective in decreasing pre-load and after-load of both right and left ventricle by a positive lusitropic effect and a reduction of systolic stress, thereby increasing the cardiac index. In group D patients maintenance of cardiac output has been demonstrated to be dependent on a chronotropic effect. As a consequence in group D the increase in rate-pressure product has reached potentially dangerous values, reflecting a marked increase in myocardial oxygen consumption. On the contrary in Group E the increase in rate-pressure product has been much more limited. Finally both drugs have proven effective, since all patients have been easily weaned from CPB. CONCLUSIONS: Enoximone is a useful and easily-handled drug to facilitate weaning from CPB of patients with preoperative impaired ventricular function.

[Intramuscular and oral clonidine in premedication of the heart surgery patient: hemodynamic effects and interaction with high-dose fentanyl induction]. / Clonidina i.m. e per os nella premedicazione del paziente cardiochirurgico: effetti emodinamici ed interazioni con alti dosaggi induttivi di fentanyl.

OBJECTIVE: The aim of the study was to evaluate the efficacy of oral and i.m. clonidine as premedication in reducing the requirements of fentanyl for induction and to analyze its effects on the hemodynamics of patients with ischemic heart disease. SETTING: University Hospital. MATERIALS AND METHODS: The authors considered 30 patients (27 male and 3 female) undergoing CABG. Patients were premedicated 60-90 min before induction of anesthesia and were randomly distributed in three groups: Group A: oral diazepam 0.1 mg x kg -1; Group B: oral diazepam 0.1 mg x k-1 + oral clonidine 5 micrograms x kg-1; Group C: oral oral diazepam 0.1 mg kg-1 + i.m. clonidine 4 micrograms x kg-1. Induction of anesthesia was realized with fentanyl at speed of 500 mcg x min-1 until loss of consciousness was reached (no answer to three consecutive questions). MEASUREMENT: Hemodynamic data were recorded at TO(baseline), T1(induction of anesthesia), T2(3 min after intubation), T3(3 min. after skin incision). Results were analyzed by utilizing the average comparison Student "t" test and paired "t" test. A value of p < 0.05 was regarded as statistically significant. MAIN RESULTS: In groups B and C the inductive dose of fentanyl was much lower (p < 0.001) compared to control group (B = 19.23 +/- 3.57 micrograms x kg-1; C = 19.92 +/- 4.15 micrograms x kg-1; A = 28.39 +/- 6.4 micrograms x kg-1). This difference remained statistically significant (p < 0.001) also at T2 and T3 (T1: A = 42.79 +/- 3.21 mcg x kg-1; B = 29.07 +/- 6.18 micrograms x kg-1; C = 29.84 +/- 5.46 micrograms x kg-1; T2: A = 57.28 +/- 5.32 micrograms x kg-1; B = 43.22 +/- 3.87 micrograms x kg-1; C = 43.48 +/- 4.25 micrograms x kg-1). Considering the hemodynamic data, we report the heart rate in group B increased at T2 (p < 0.01), and systolic artery pressure raised in groups A (p < 0.05) and C (p < 0.01) at T2. Compared to baseline cardiac index showed a decrement at T3 in all groups of patients (p < 0.05). Systemic vascular resistance increased in all groups at T3 compared to baseline (p < 0.05). CONCLUSIONS: Clonidine proved to be useful to reduce narcotic requirements and to provide hemodynamic stability.