Norepinephrine can be useful for the treatment of right ventricular failure combined with acute pulmonary hypertension and systemic hypotension. A case report.

A 48-year-old woman who underwent emergency cardiac surgery for removal of a thrombus partially occluding the mitral valve, developed pulmonary hypertension right ventricular failure and systemic hypotension, in the immediate postoperative period, a clinical condition not well controlled by high doses of epinephrine and dobutamine. The addition of a continuous infusion of norepinephrine in incremental dosages, caused the rise in cardiac index accompanied before by the reduction in the pulmonary pressure and the stability in the systemic pressure, than by the further reduction in the pulmonary pressure and the increase in the systemic pressure. The conclusion is drawn that norepinephrine is useful in the treatment of right ventricular failure which follows a condition of acute pulmonary hypertension, because the improvement of cardiac performance established without adverse effects on the pulmonary pressures whose values on the contrary progressively declined.

Effects on respiratory function of the head-down position and the complete covering of the face by drapes during insertion of the monitoring catheters in the cardiosurgical patient.

BACKGROUND: We evaluated the effect on the respiratory gas exchange of the 30 degrees head-down position and the complete covering of the face by sterile drapes. These are used to cannulate the internal jugular vein and position the pulmonary artery catheter in the cardiosurgical patient. During the two manoeuvres, 20 coronary patients and 10 patients with end-stage heart disease were supplied with oxygen (FiO2 =0.4) by a Venturi mask, while 20 coronary patients breathed room air. The arterial blood samples to measure oxygen (PaO2) and carbon dioxide (PaCO2) tension and oxygen saturation (SaO2) were analysed by a blood gas system. RESULTS: The contemporary application of the head-down position and the drapes over the face significantly increased PaO2 and SaO2 in all the patientssupplied with oxygen. Without the head-down position, leaving the drapes over the face, did not significantly change the two parameters in the coronary patients supplied with oxygen, but induced a significant increase in PaO2 and SaO2 in the patients with end-stage heart disease. In the coronary patients that were breathing room air, PaO2 and SaO2 were stable throughout the study. CONCLUSIONS: We conclude that the 30 degrees head-down position and the complete covering of the face by drapes does not interfere with respiratory gas exchange and can be safely performed in coronary patients supplied with oxygen or breathing room air and in patients with end-stage heart disease supplied with oxygen (FiO2 of 0.4).

Prevention of acute renal failure in major vascular surgery.

The aim of this study was to analyse the main problems which involve renal function in major vascular surgery and can lead to postoperative acute renal failure. The factors responsible for renal damage in this surgical branch are at first analysed, then followed by the physiological changes which characterize the renal injury, the techniques employed to detect and monitor them and finally the therapeutic tools available to prevent acute renal failure. The most significant data of personal experience on the use of nifedipine and low-dose dopamine during abdominal aortic surgery are then presented. It is concluded that: a) an ischemic attack is the main cause of acute renal failure in mayor vascular surgery; b) prevention of ischemic renal damage is far superior to treatment; c) the optimal management of the cardiovascular function by means of the invasive hemodynamic monitoring, is the main tool to protect the kidneys and prevent acute renal failure; d) the pharmacological protection by diuretics and low-dose dopamine is of minor importance and anyway subordinate to the maintenance of adequate hemodynamics, as well as for calcium antagonist whose employment however seems to protect the kidneys better against an ischemic attack.

Comparison of intravenous nifedipine and sodium nitroprusside for treatment of acute hypertension after cardiac surgery.

BACKGROUND: The present study was designed to compare the hemodynamic effects of nifedipine and sodium nitroprusside, intravenously administered to control acute systemic hypertension in the immediate postoperative period after open heart surgery. METHODS: The study was carried out on 16 patients who developed acute systemic hypertension, defined as mean systemic arterial pressure (MAP) values above 90 mmHg, within the first hour after ICU admission, which followed cardiac surgery for valvular and coronary disease. After control measurements during the hypertensive status, each patient was treated by alternating infusions of sodium nitroprusside and nifedipine in order to obtain MAP values of about 80 mmHg with each administration. All patients had preoperative left ventricular ejection fraction above 45%. RESULTS: Nifedipine produced a superior and significant increase in cardiac index (CI) (+28%) and stroke volume index (SVI) (+30%), and a greater decrease in systemic vascular resistance index (SVRI) (-39%), when compared with sodium nitroprusside [CI (+5%), SVI (no change), SVRI (-27%)]. On the contrary the right and left ventricular filling pressures were reduced significantly by sodium nitroprusside [pulmonary capillary wedge pressure (-30%), central venous pressure (-20%)], while nifedipine induced small and not significant changes in the preload values. No ECG changes suggesting ischemic myocardial events were observed in any patient. CONCLUSIONS: On the basis of these results it has been concluded that nifedipine affects primarily the arteriolar resistance vessels without significant changes in venous tone, which is on the contrary markedly reduced by sodium nitroprusside. The better improvement in cardiac index and stroke volume index obtained with the administration of nifedipine, makes this drug a good alternative to sodium nitroprusside for treatment of acute hypertension after cardiac surgery in patients with a good preoperative left ventricular function.

[Circulatory instability in potential donor organ patients in a state of brain death. Investigation of predictive factors]. / Instabilità circolatoria nei pazienti in stato di morte cerebrale potenziali donatori d'organo. Ricerca di fattori predittivi.

OBJECTIVE: To assess the factors influencing and predicting the degree of circulatory impairment of the brain-dead cardiac donors (BDCD). DESIGN: Retrospective study. SETTING: General ICU of a 1400 bed High Specialty Regional Hospital. PATIENTS: 53 patients undergoing brain death (BD) assessment as suitable cardiac-donors. INTERVENTIONS: Fluids were given up to a central venous pressure (CVP) > 5 mmHg and adrenergic drugs in a sequential manner trying to keep the systolic blood pressure > 90 mmHg. METHODS: Every hour during the time of BD assessment were recorded: invasive blood pressure (BP), CVP, fluid balance, the demographic data, the dosage of adrenergic drugs, the cause of admission, the time from admission to ICU to BD, the report of an echocardiogram. The patients were divided into 4 classes according to the dosage of the adrenergic drugs required to achieve the pressure-goal. The 4 classes were compared for the above mentioned parameters. RESULTS: No differences were found among the 4 groups. CONCLUSIONS: In BDCD the degree of circulatory instability and vasopressor needs cannot be anticipated by the parameters examined. This could be due partly to the relative homogeneity of these patients, since they underwent a clinical selection and similar interventions, partly to a possibly inadequate standard of monitoring. Anyway the unique hemodynamic situation after BD is probably not very affected by the previous events. Further studies are necessary to explain the variability of the circulatory instability and to assess its effects on the quality of the transplanted organs.

Effects on renal function of a continuous infusion of nifedipine during cardiopulmonary bypass.

OBJECTIVES: To evaluate the effects on renal function of continuously administered nifedipine during cardiopulmonary bypass (CPB) in patients undergoing cardiac surgery. DESIGN: The study was prospective, randomized, and controlled. SETTING: The study was performed in the Department of Anesthesia and intensive care unit of a regional hospital in Italy. PARTICIPANTS: Thirty-four patients scheduled for elective coronary artery surgery; all patients had preoperative renal and hemodynamic function within normal limits. INTERVENTIONS: The patients were randomly divided into two equal groups: nifedipine and control. Twenty patients were included in the study: 10 patients in the nifedipine group (group A) and 10 patients in the control group (group B). In group A, nifedipine was continuously administered during CPB at an infusion rate ranging from 0.24 to 0.59 micrograms/kg/min to maintain the mean systemic arterial pressure (MAP) between 60 and 70 mmHg. In group B, increases of MAP above 70 mmHg were treated with IV boluses of urapidil (5 mg). MEASUREMENTS AND MAIN RESULTS: Renal function was studied using creatinine clearance (CRCL), determined before, during, and after the operation, and the glomerular filtration rate (GFR) was measured the day before and after the operation by plasma and urine clearance of 51-chromium edetic acid (51Cr-EDTA). Hemodynamic monitoring was performed using a pulmonary artery catheter. In comparison with preoperative determinations, CRCL and GFR values increased significantly after CPB (p < 0.001) and after the operation (p < 0.01) in the patients treated with nifedipine, whereas the two parameters showed a small and not significant reduction at the same times in the control patients. Hemodynamic function was well maintained in all patients throughout the study. CONCLUSIONS: It is concluded that, besides the maintenance of adequate hemodynamics, a continuous infusion of nifedipine during CPB can be an additional therapeutic tool to protect renal function in cardiac surgical patients.

Nifedipine can preserve renal function in patients undergoing aortic surgery with infrarenal crossclamping.

Sixteen patients diagnosed with an aneurysm of abdominal aorta or Leriche disease underwent elective aortic surgery involving crossclamping of infrarenal aorta (ICC). These patients were randomized into two equal groups and 8 patients were infused with nifedipine starting from the isolation of aorta until the end of surgery (group A) while another 8 patients were infused with low-dose dopamine (group B) over the same surgical course. Plasma endothelin (ET) was measured before the induction of anesthesia, at the beginning and at the end of the clamp period and at the end of the operation. Intraoperatively, creatinine clearance and urinary excretion of PGE2, 6-keto PGF1 alpha and TxB2 were also determined before, during and after aortic crossclamping. Preoperative GFR as well as preinduction cardiac index (CI) and pulmonary capillary wedge pressure (PCWP) of the two groups did not differ. During cross-clamping plasma ET rose significantly in both groups. However, after clamp removal, plasma ET decreased in group A while it remained elevated in group B. Urinary excretion of TxB2, PGE2 and 6-keto PGF1 alpha increased during clamp in both groups, but the ratio of PGE2 + 6-keto PGF1 alpha/TxB2 during and after clamp was significantly higher in group A than in B. Postclamp creatinine clearance decreased in group B, and increased in group A; postoperative value of GFR was unchanged in group A and decreased significantly in group B. In conclusion, infusion of nifedipine, in contrast to dopamine, prevented the decrease of GFR in patients undergoing aortic surgery. This effect could be mediated by a nifedipine modulation of ET vascular synthesis and/or a preferential renal synthesis of vasodilating prostanoids.

[The thermodilution determination of right ventricular volumes and ejection fraction in the critical patient. Volumetric vs pressure measurement assessment]. / Determinazione mediante termodiluizione dei volumi e della frazione di eiezione del ventricolo destro nel paziente critico. Valutazione volumetrica vs pressumetrica.

The widespread use of hemodynamic investigation techniques, allowed a better understanding of the right ventricle (RV) pathophysiology and led to progressive reevaluation of its role. A modification of the classical Swan-Ganz catheter, made possible the measurement of the ejection fraction (EF) and of the end-systolic and end-diastolic volumes of RV just by the simple application of the thermodilution technique. In this paper, we first refreshed the basic theoretical principles of the technique and then presented our preliminary results of one-year experience in ICU. A non-homogeneous group of 36 critically ill patients (septic shock 17, COPD 13 and ARDS 6) was studied. Specifically we found that neither the data of central venous pressure nor those of RV end diastolic pressure, were able to estimate the real preload, i.e. RV end diastolic volume (r = 0.01 and r = 0.03 respectively with "p" not significant). We compared the data of RV EF with that of the end systolic pressure/volume (P/V) ratio in a group of patients before and during the administration of dobutamine to evaluate their sensitivity to identify changes of contractility. The results obtained support the superiority of RV end systolic P/V ratio over RV EF to detect variations of contractile status. We conclude that the use of the thermodilution technique to measure the volumes of RV, allows a real evaluation of the preload. At the same time it avoids all the problems associated with the measurement of transmural pressure and with the changes produced by shifting of intrapleural pressure. Finally the end systolic volume may be combined with the pressure data to estimate the contractile status and, in our experience, this parameter has proved more sensitive than EF in order to detect changes of contractility of the right ventricle.

[Continuous monitoring of mixed venous oxygen saturation during mechanical circulatory support of the left ventricle in heart surgery patients. Pathophysiologic principles and personal experience]. / Monitoraggio continuo della saturazione venosa mista durante assistenza circolatoria meccanica del ventricolo sinistro, nel paziente cardiochirurgico. Presupposti fisiopathologici ed esperienza clinica personale.

The clinical use of mechanical supports for cardiocirculatory function assistance has permitted to treat a higher number of low output syndromes insensitive to pharmacological therapy. One of the most important problems arising during mechanical circulatory assistance, is the ability to know if the performance of the artificial device is adequate to match metabolic tissues demands. Continuous monitoring of mixed venous O2 saturation (MSvO2) has been proposed as the most complete and reliable tool to verify this correlation. The Authors analyse the problems connected with this kind of monitoring during left ventricular assistance with centrifugal pump in cardiosurgical patients and present 6 cases taken from their clinical experience.

[Peridural anesthesia and narcosis with propofol in thoracic surgery]. / Anestesia peridurale e narcosi con propofol in chirurgia toracica.

Twelve patients undergoing elective thoracic surgery because of lung cancer, have been studied. The anesthetic management included: continuous epidural anesthesia with bupivacaine (T6-T7), continuous infusion of propofol and vecuronium, mechanical ventilation with an oxygen/air mixture. We evaluated the perioperative analgesia and the cardiovascular side effects of two groups of patients differing for the position (supine or lateral) selected to administer the local anesthetic. We also analysed the most important characteristics of the recovery from anesthesia (degree of analgesia and consciousness, respiratory function and cooperation with physiotherapeutic manoeuvres). The authors conclude that, although the number of patients studied is limited, there are no significant differences between the two groups for intraoperative analgesia and hemodynamic imbalance; the anesthetic technique employed is a reliable alternative to classic balanced anesthesia, because seems to reply very well to the mayor purposes of thoracic surgery. Moreover it makes the operative room free from pollution caused by volatile anesthetics.

[Antibioticotherapy based on statistics in intensive therapy]. / Antibioticoterapia su base statistica in terapia intensiva.

The authors present the epidemiological data concerning nosocomial infections in their Intensive Care Unit, and discuss an antibiotic strategy statistically oriented by these data. In their experience, treatment based on statistical criteria, brought to a reduction in antibiotic consumption with particular regard to broad-spectrum antibiotics, and to a decrease in individual budget.