Changes of serum magnesium ions in open heart surgery.

The changes of magnesium in the serum were studied in 20 patients undergoing cardiac valve substitution procedures in extracorporeal circulation. The serum magnesium ions were determined before the onset of the anesthesia, at the beginning and at the end of the extracorporeal circulation, at the end of surgery and during the first post-operative day. A slight magnesium ion deficiency was observed even in the initial serum levels, probably due to the pre-operative diuretic therapy. The hypomagnesemia observed during the bypass was related to haemodilution and urinary losses. A limited increase in magnesemia, probably caused by the diffusion of the ion towards the vascular compartment, was observed at the end of the extracorporeal circulation. A new decrease was found during the post-operative stage, perhaps caused by the action of diuretics, which were administered.

Magnesium metabolism in open-heart surgery.

The levels of magnesium in serum, urine and erythrocytes were studied in 22 patients undergoing cardiac surgery for valvular prosthesis. Magnesium values were correlated with serum albumin and non-esterified fatty acids (NEFA). Data were collected before anesthesia, 10 min after sternotomy, heparinization and declamping of the aorta and in the 1st postoperative day. A slight decrease in magnesemia was observed before extracorporeal circulation (ECC) and was mainly due to haemodilution. The correlation of magnesium with NEFA was significant only after heparinization. The use of the St Thomas solution as cardioplegia fully corrected the hypomagnesemia previously reported during ECC as well as in the 1st postoperative day. A moderate hypermagnesemia was observed at the end of ECC, but no patient reached dangerous levels of serum magnesium. Urinary losses increased during and after ECC. Red blood cell magnesium showed a slight increase before ECC, followed by a significant reduction at the end of ECC.

Nutrition in acute renal failure.

The nutritional value of regimes enriched with branched chain amino acids has been evaluated in 22 adult patients suffering from acute post-traumatic renal failure. The study was carried out for 12 days. The following data were recorded and compared daily: nitrogen balance, daily blood urea nitrogen (BUN), BUN/creatinine ratio, and plasma albumin levels. Also after 6 days of dialysis and nutritional support, the plasma medium molecular weight compounds (uremic toxins) were studied. It was concluded that: (a) the combined use of parenteral and oral nutrition appears most adequate in this type of patient; (b) the nitrogen intake should provide an essential amino acid/total nitrogen ratio of greater than or equal to 4 and a branched chain essential amino acid ratio of greater than or equal to 0.5; and (c) caution is still necessary in interpreting analyses of middle molecular weight compounds in this type of patient.

Haemodynamic and metabolic effects of surface rewarming after coronary revascularization.

Cardiac surgery is often associated with a postoperative increase in the patient's metabolic rate; surface rewarming has been suggested to decrease the energy expenditure by preventing hypothermia. Thirty patients, undergoing coronary revascularization, were randomly divided into two groups; after surgery group A was rewarmed by a new device that acts by both conduction and convection, while group B was just covered with cotton blankets. Blood, oesophagus and skin (thigh and foot) temperatures were recorded on admission to the intensive care unit (ICU) and 30, 60, 90, 180, 270, and 450 min later. Haemodynamic parameters, oxygen delivery, calculated oxygen consumption, and plasma lactate concentration were assessed as well. Group A warmed up quicker than group B as far as the skin was concerned while the core temperature was unaffected. Group A was also characterized by lower cardiac indices and oxygen consumption. As the occurrence of a dependence of oxygen consumption on delivery could be reasonably ruled out in warmed patients because blood lactate levels were lower than in the controls, we conclude that surface rewarming might have some positive effect in decreasing metabolic demand after cardiac surgery even if the patient's core temperature is little affected. The inhibition of skin temperature receptors could possibly explain this finding.

Red blood cell energy metabolism during cardiopulmonary bypass.

BACKGROUND: During cardiopulmonary bypass (CPB) an intracellular ATP deficit could theoretically play a role in changes of erythrocyte shape and deformability caused by mechanical trauma. We therefore studied erythrocyte energy metabolism in 12 patients undergoing normothermic CPB for myocardial revascularization. METHODS: Blood samples were collected prior to and 45 minutes after CPB beginning and analyzed for erythrocyte ATP, ADP, and AMP and their metabolites, erythrocyte NAD and NADP, plasma and whole blood lactate (Lact(p) and Lact(b) respectively), and whole blood pyruvate (Pyr(b)). RESULTS: Values were expressed as mean +/- standard deviation or median (lower and higher quartiles) on the ground of a test for normality. During CPB erythrocyte nucleotides and their metabolites did not change significantly (ATP: 60.2+/-12.1 vs. 68.3+/-13.0; ADP: 12.2+/-3.6 vs. 12.0+/-3.1; AMP: 0.43+/-24 vs. 0.44+/-0.26; adenosine: 0.063 (0.034-0.203) vs. 0.77 (0.032-0.221); inosine: 0.064 (0.023-0.072) vs. 0.075 (0.025-0.111); hypoxanthine: 0.330+/-0.272 vs. 0.367+/-0.223; xanthine: 0.193+/-0.090 vs. 0.220+/-0.095; NAD: 3.149+/-0.743 vs. 3.358+/-0.851; values in microM/mM packed red blood cell hemoglobin) while NADP increased (2.110+/-0.390 vs. 2.433+/-0.288 microM/mM packed red blood cell hemoglobin; p<0.05). Ringer lactate, with which the extracorporeal circuit was primed, caused Lact(p) to increase (1.87+/-0.81 vs. 3.27+/-1.15 mM/l; p<0.01). Some lactate entered erythrocytes since Lact(p)/Lact(b) ratio did not change (1.09+/-0.25 vs. 1.07+/-0.23) and some was transformed into pyruvate since Pyr(b) increased [62.9 (30.3-73.3) vs. 100.5 (61.0-146.9) microM/l; p<0.01]. Lact(b)/Pyr(b) ratio did not change significantly [22.6 (16.1-40.5) vs. 27.9 (17.5-35.2)] so that NAD/NADH ratio and, consequently, the rate of glycolysis were unlikely to change too. CONCLUSIONS: Erythrocyte energy metabolism is not affected by CPB, at least during the period of time taken into account in this study.

Anesthetic management of pheochromocytoma in a long term hemodialysed patient.

The anesthetic management of a hemodialyzed patient with a dopamine producing pheochromocytoma is described. A 56-years old man underwent surgical procedure the day after hemodialysis. Prior to intervention adrenal cortex hormones were normal as well as other endocrine variables (T3-T4-TSH-cortisol-ACTH-parathyroid hormone); epinephrine and norepinephrine, were in a normal range while dopamine was elevated (185 pg/ml). Preoperatively the patient was alpha-blocked with oral phenoxybenzamine (20 mg/day). A balanced anesthesia was performed (isoflurane and fentanyl). Plasma catecholamines were determined. During the induction of anesthesia and before tracheal intubation phentolamine and labetalol were injected till 3.4 mg and 50 mg total dose respectively. During surgical manipulation a nitroglycerin infusion was started (1.5 gamma/kg/min) and after tumor resection dopamine was given till 15 gamma/kg/min. Hormonal values increased in presence of unchanged hemodynamic parameters, likely due to alpha and/or beta blockade. In this case report our problem was especially fluid replacement after tumor resection, because of renal failure. On the basis of CVP and PCWP values, fluid treatment and dopamine infusion allowed to achieve an adequate preload. A sufficient level of analgesia and an efficient alpha blockade may assure hemodynamic stability also in a so compromised patient status.

National character does not reflect mean personality trait levels in 49 cultures.

Most people hold beliefs about personality characteristics typical of members of their own and others' cultures. These perceptions of national character may be generalizations from personal experience, stereotypes with a "kernel of truth," or inaccurate stereotypes. We obtained national character ratings of 3989 people from 49 cultures and compared them with the average personality scores of culture members assessed by observer ratings and self-reports. National character ratings were reliable but did not converge with assessed traits. Perceptions of national character thus appear to be unfounded stereotypes that may serve the function of maintaining a national identity.

[Changes in intraerythrocyte electrolytes in open-heart cardiosurgical interventions]. / Variazioni degli elettroliti intraeritrocitari negli interventi cardiochirgici a cuore aperto.

The changes of erythrocyte Na, K, C1, and Mg during open-heart surgery were studied in 10 patients undergoing aorto-coronary bypass and in 10 patients undergoing valvular replacement and chronically treated with digitalis and diuretics. The results showed: initial Mg levels lower in both groups of patients than in 10 healthy subjects utilized as controls (p less than .01); higher initial Na levels in patients treated with digitalis and diuretics than in controls (p less than .001); no electrolyte change during extracorporeal circulation; significantly increased Na values at the end of surgery and in the 1st postoperative day, that were probably caused by erythrocyte damage during CPB. The increase was observed following the CPB because of the slow rate of erythrocyte Na changes.

Erythrocyte electrolyte abnormalities.

In contrast to lymphocytes and skeletal muscle cells, erythrocyte electrolytes may be easily determined. In this study Na, K, and Mg concentrations in plasma and erythrocytes of 100 consecutive ICU patients were compared to evaluate their potential clinical usefulness. The predictive indices of electrolyte changes in plasma vs. those in erythrocytes were low for all of the electrolytes studied. The erythrocyte Mg assessment was particularly useful for the high frequency of abnormalities observed, because it was less affected than plasma Mg by such transitory clinical states as hemodilution or lipolysis. The erythrocyte K was less frequently altered; no patient with a high K deficit was studied, excluding one patient with Crohn's disease. Finally, abnormally high erythrocyte Na levels correlated closely with some pathologic status, in particular respiratory failure.

Compartmental analysis of lidocaine kinetics during extracorporeal circulation.

The aim of this study was to measure the effects of extracorporeal circulation (ECC) on lidocaine disposition and to determine if therapeutic concentrations were achieved during ECC. Anesthesia was obtained by administration of fentanyl (50 microg/kg plus 0.3 microg/kg/min) and pancuronium bromide (0.1 mg/kg) along with controlled ventilation (10 mL/kg, PaCO2, 30 to 34 mmHg). Lidocaine was administered to ten patients in bolus doses of 2 mg/kg at the time of endotracheal intubation and during ECC at aortic declamping. Samples were collected at 20 and 40 seconds, and at 1, 3, 5, 10, 15, 20, 25, and 30 minutes after drug administration. Blood sampling was arterial during anesthesia induction and from the oxygenator during ECC. Blood levels of lidocaine were determined by the immunofluorescence method. The kinetic studies of lidocaine showed increases in plasma volume and in the volume of the peripheral compartment, along with decreased volume in the compartment of well-perfused tissues during ECC. The fraction of the dose of lidocaine administered during ECC behaved accordingly, showing a decrease in the quantity of drug in the well-perfused tissues, and an increase in the other two compartments when compared to values before ECC. The doses administered gave plasma concentrations of 1.55 microg/mL, which are considered therapeutic. Thus, it is not recommended to increase the lidocaine dosage during ECC.

Evaluation of stress-related hormones after surgery by laparoscopy or laparotomy.

STUDY OBJECTIVE: To evaluate the stress hormone response after pelvic surgery performed by laparoscopy versus laparotomy. DESIGN: Prospective study. SETTING: A tertiary care university hospital. PATIENTS: Ten women were scheduled to undergo laparoscopic surgery and 10 laparotomy for either tubal disease or endometriosis. INTERVENTIONS: Surgical procedures were performed by laparoscopy or laparotomy for stage III-IV endometriosis, pelvic adhesions, or distal tubal occlusion. The following hormones were measured before the induction of anesthesia in the ward, 60 minutes after the beginning of surgery, at the end of surgery after extubation, and 2 hours and 6 hours after the end of the operation: norepinephrine (NE), epinephrine (E), dopamine (D), adrenocorticotropic hormone (ACTH), cortisol, prolactin (PRL), and GH. MEASUREMENTS AND MAIN RESULTS: The mean duration of surgery was not significantly different between the two groups. Surgery-related adrenergic activation (E, NE, D) appears more pronounced in the laparotomy group (p<0.005) during surgery and in the postoperative period. More elevated values for laparotomy were observed also for the other stress hormones (ACTH, cortisol, PRL, GH), even though statistical significance was not always reached. CONCLUSIONS: Compared with laparotomy, activation of stress-related factors during laparoscopy seems to be less intense and of shorter duration.

Pulsatile normothermic cardiopulmonary bypass and plasma catecholamine levels.

The aim of the study was to assess plasma catecholamine levels in patients undergoing myocardial revascularization and relate them to pulsatile (P) and nonpulsatile (NP) normothermic cardiopulmonary bypass (CPB). Twenty-eight patients were randomly assigned to different CPB management: 15 patients were assigned to group 'P', 13 patients to group 'NP'. During normothermic extracorporeal circulation, group 'P' received pulsatile perfusion, while group 'NP' received nonpulsatile perfusion. Levels of epinephrine and norepinephrine were evaluated during the operation and in the intensive care unit (ICU), at seven time points. Haemodynamic assessment was performed at four time points in the same period. Demographic and surgical data were collected, and the postoperative course was analysed. Epinephrine levels were markedly increased during CPB in both groups, while norepinephrine increased more in group NP in comparison with group P. No significant difference was found in fluid administration, transfusion, drugs usage, or postoperative complications. Normothermic pulsatile CPB seems to achieve reduced levels of norepinephrine. A clinical beneficial effect of this finding was not demonstrated during the study.

Paroxystic hypertension in a long-term hemodialyzed patient. Successful adrenalectomy for a dopamine-producing pheochromocytoma.

Pheochromocytoma (Pheo) is an uncommon neoplasm producing blood pressure troubles and it may be undiagnosed in chronic dialyzed patients in whom hypertension is a common finding. The symptoms in Pheo syndrome depends on the prevalent catecholamine released, the most common being epinephrine (E) and norepinephrine (NE). Recently, a particular clinical picture has been described for dopamine (DA)-producing Pheos, in whom a normo-hypotensive status is more often observed. The authors report a case of mainly dopamine-producing Pheo in a long-term dialyzed patient, successfully treated with adrenalectomy. The main steps in diagnosis and preoperative management are described and debated also in view of the particular background produced by the end-stage renal failure. The common imaging techniques adopted for adrenal medullary neoplasms (US, CT, MIBG scintiscan) confirmed to be decisive for diagnosis; HPLC assay of plasma catecholamines is the only biochemical test available in these patients although its significance is questionable due to the poor knowledge of catecholamine metabolism in chronic renal failure. The clinical findings observed in this case seem in disagreement with those already reported in DA producing Pheos. Pheo in hemodialyzed patients is a rare event and it may be hidden by other more common causes of hypertension. However, more awareness from the medical staff allows to diagnose the neoplasm correctly by the currently available methods and to plan a safe surgical therapy also in high-risk patients.