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Biomedical subjects

I Giovannini

Publications and source records attributed to I Giovannini.

At least 37 records · Page 2Linked to original sources
PubMed1996

Hepatic resections in normothermic ischemia.

BACKGROUND: Reduction of operative blood transfusions is a primary goal in resective surgery of the liver. Temporary vascular inflow occlusion is an effective method to decrease hemorrhage during hepatic resection. This study was performed to assess the impact of normothermic ischemia on intraoperative bleeding and outcome after hepatic resection. METHODS: Sixty-one hepatic resections were performed by using pedicle clamping alone or associated with total vascular exclusion of the liver. The mean duration of normothermic ischemia was 40 +/- 18 minutes (range, 7 to 98 minutes). Major resections were performed in 32 cases (52.5%). RESULTS: Operative mortality was nil. Major complications occurred in 11.5% of cases. Twenty-five patients (41%) received intraoperative blood transfusions; mean +/- SD of transfused blood units was 2.4 +/- 1.3. Twelve major resections (37.5%) did not require any transfusion. Postoperative changes in liver function test results were moderate and transient. CONCLUSIONS: The results of this study confirm the benefit of vascular occlusion techniques in reducing intraoperative bleeding and postoperative complications. The routine use of these techniques during hepatic resections, if applied properly and with the necessary precautions, is not associated with severe adverse effects on liver function.

Adolescent↗
PubMed1994

[The surgical risk of liver resections for neoplasms in the elderly patient].

For patients who are candidates for surgical resection of the liver, advanced age has, for many years, been considered to be a limiting factor or has precluded intervention. More recently, improvements in diagnostic, surgical and anaesthetic techniques and the increase in the average age of the population have gradually broadened the indications for hepatic resection in elderly patients. The factors for reappraisal of the surgical risk of liver resection in elderly patients are discussed here. Comparative data are also presented on the mortality, morbidity and post-operative changes in blood chemistry parameters in 90 patients who underwent hepatic resection: 33 patients over 65 years of age (group A) and 57 under 65 years (group B). In group A, compared to group B, mortality (3% versus 5%) and the percentage of patients with post-operative complications (27% versus 37%) were not significantly different. The incidence of post-operative complications correlated more closely with specific risk factors (elevated pre-operative "ASA score" from associated disease) than with age itself. Analysis of the regressions did not reveal important relationships between age and changes in the blood chemistry parameters. These results help to support the idea that advanced age alone is not now an absolute contra-indication to major liver resection.

Age Distribution↗
PubMed1994

[The choice of substrates in total parenteral nutrition].

This review contains a full outline on the choice of substrates in total parenteral nutrition (NPT). The basic properties of "conventional" substrates (glucose, long chain triglyceride-containing fat, common amino acid mixtures) are used to outline the general principles for NPT support in normal conditions and in stress (surgical and nonsurgical trauma, sepsis). Without taking into account factors which are not strictly metabolic (vascular access, local availability of products, costs), particular attention is then paid to "non-conventional" substrates and substrate mixtures, including some under study, with specific reference to properties and features which may motivate their choice.

Amino Acids↗
PubMed1993

Computational logic: a method for formal analysis of the ICU knowledge base.

The object of clinical computing is to support the making of clinical decisions. This takes place in an integrated context of care that involves processes of three different kinds: (1) the physiologic processes in the patient, (2) the processes of physiologic data as stored in, and moved within, a distributed computing system, and (3) the therapeutic and decision-making processes of the clinical staff. The clinical computing system is complex, and as we press it further to work as a partner in the complete care context, it tends to become unmanageably so. In this article, we try to suggest how one might begin using a formal mathematical theory, called 'computational logic,' to give theoretical analyses that might help one to understand the computing system and thereby to try to increase its ability to meet demands on it, and might help one to understand the care context as a whole. We examine the three levels, one at a time, looking for structural analogies between them, and trying to identify the ways that they are linked together. Computational logic provides us with a common set of notions for doing so.

Artificial Intelligence↗
PubMed1993

Calculation of venoarterial CO2 concentration difference.

Quantitative relationships in CO2 transport and exchange processes were combined for use as the basic components of an original mathematical model for the calculation of venoarterial blood CO2 concentration difference (v-aDCO2). This is calculated as the sum of the increment in CO2 concentration (CCO2) related to the increase in CO2 tension (delta P) from arterial to venous value at constant O2 saturation (delta CCO2/delta P) and of the increment in CO2 concentration related to the decrease in O2 saturation (delta S) from arterial to venous value at constant CO2 tension (delta CCO2/delta S). The newly developed relationships correlated well with the experimental data from which they were derived (r2 = 0.94-0.99). The results provided by the model compared remarkably well with the results of previously published measurements (r2 = 0.96-0.99). This new model allows one to overcome some of the limitations implicit in previously available methods and provides a useful tool for the assessment and monitoring of hemodynamic, metabolic, and O2-CO2 exchange patterns in whole body and regional vascular beds.

Arteries↗
PubMed1990

Probability and the patient state space.

This paper describes work to develop a model-based system to support clinical decision-making. In previous articles, we have developed (from 695 measurement sets obtained from 148 patients) a physiologic state classification based on a set of 11 cardiovascular and metabolic measurements. There is an R or reference state, for stable ICU patients. Patients under (operative, traumatic, or compensated septic) stress, or with (septic or hepatic) metabolic, respiratory, or cardiac insufficiency are in the A, B, C, or D states, respectively. We wished to make the state easier to measure and eventually available continuously, automatically, and noninvasively, as well as reflecting a wider group of bodily systems. The 5 centers define a 4 dimensional affine subspace, designated the cardiovascular state space. Using eigenvector analysis, we have found four new derived physiologic variables CV1, CV2, CV3, and CV4 that span the state space. We have fit sets of linear regression equations that allow the patient's position in the state space, and therefore his state, to be determined from more easily obtainable sets of measurements. Further, we selected 1966 measurement sets from 512 patients at two hospitals. We used the data from 250 of these patients to define 13 prototypical types, namely survivors and deaths from various combinations of sepsis, cardiogenic decompensation, cirrhosis, and pneumonitis, following trauma or general surgery. For any future patient, the statistical theory of Bayesian inference allows one to infer back from the measurements observed to the probability of his being of any of these types and of surviving or dying. We used this method to predict the outcome of the other 262 patients, prospectively. Statistically, the predictions of survival or death were not significantly different from the actual. For individual patients, the method predicts a clinical course that closely follows the actual episodes in their history. These results confirm and explain the validity of the concept of the patient state and make the state easier to compute. The patient state and the probability plot together help to stage, select, and evaluate therapy. They do not replace the clinician's judgement, but rather are tools that help the clinician to exercise judgement.

Adult↗
PubMed1990

Relationship of plasma cholesterol level to doses of branch-chain amino acids in sepsis.

Plasma cholesterol levels, plasma lactate, and total body RQ were measured in septic patients undergoing total parenteral nutrition (TPN) with glucose, fat, and two different branch-chain amino acid admixtures (49% BCAA and 16% BCAA). Mean plasma cholesterol for all measurements (2.61 +/- 0.94 [SD] mmol/L) was lower than normal; however, it was higher with 49% BCAA than with 16% BCAA (2.94 +/- 0.95 vs. 2.27 +/- 0.81 mmol/L, p less than .001) for comparable loads of glucose, fat, and total amino acids. Plasma lactate and RQ were lower with 49% BCAA than with 16% BCAA (p less than .001 for both). Cholesterol was directly related to the absolute dose of BCAA (p less than .001), was unrelated to the dose of non-BCAA, and was inversely related to lactate (p less than .001). These results suggest that BCAA ketoacids contribute to cholesterol synthesis in sepsis, as well as being an oxidative source. The data also suggest that the reduction in alanine in BCAA-enriched amino-acid TPN assists in the lowering of plasma lactate secondary to abnormal septic glucose metabolism.

Adult↗
PubMed1989

Noninvasive surveillance of allografted kidneys by ultrasonic duplex scanning.

Over a one-year period 1,000 duplex Doppler evaluations were performed in 70 patients submitted to kidney transplantation for end-stage renal failure. Duplex monitoring was performed to evaluate transplant status from hemodynamic patterns of the graft arteries. A duplex scanner with a 3.75 MHz sector transducer was used; pulsed Doppler was utilized to detect blood flow velocities in the main renal, segmental, interlobar and arcuate arteries. Arterial signals were quantified through a pulsatility index (PI). Three cases of acute rejection (AR), 9 cases of chronic rejection (CR), 2 cases of cyclosporine nephrotoxicity (Csa Tox), and 4 cases of acute tubular necrosis (ATN) were recognized and biopsy proved. At each arterial site PI values of normally functioning allografts were lower than 1.5; AR patients showed PI values ranging from 1.7 to 3.1, promptly lowered by immunosuppressive treatment. CR patients had a spectrum of PI from 0.5 to 3.1. Patients with Csa Tox and ATN showed in all the explored sites normal arterial signals and thus normal PI values. PI variations reflect even slight blood flow reductions due to immunologically mediated increases in intrarenal arterial resistances. Duplex sonography of allografted kidneys shows great diagnostic attitudes in the noninvasive characterization of transplant malfunction.

Adult↗
PubMed1988

Calorimetric response to amino acid infusion in sepsis and critical illness.

The effect of the infusion of mixed amino acids with glucose and fat on metabolic rate (MR) in sepsis (S) and in nonseptic trauma (NS) was investigated. The results demonstrated that diet-induced thermogenesis (specific dynamic action) controlled in S and in NS 25% and 18% of the MR variability, respectively (r2 = .25 and .18, p less than .01 for both). Also, diet-induced thermogenesis represented a quantitatively relevant portion of the total MR. There was a larger thermogenic effect of amino acids in S with respect to NS (22.3 vs. 5.7 cal/mg N, p less than .01) with a concomitantly increased thermogenic effect of fat. The results suggest the importance of recognizing the thermogenic effect of administered nutrients as an important determinant of MR during calorimetric measurements. The finding of an enhanced thermogenic effect of amino acids and fat in S also implies the need for more complete investigations of the impact of these substrates in modifying oxidative and energy metabolism in S.

Adult↗
PubMed1988

A simple method for rapid estimate of pulmonary venous admixture.

Data from 2,298 measurements of pulmonary venous admixture (QS/QT) performed in 733 patients were analyzed and processed in order to develop a method for rapid and reliable estimation of QS/QT by a simplified approach. Formulae and charts were obtained, which are easily suitable for use in all settings, and permit estimation of QS/QT with an 85%-93% control of its variability (r2 = 0.85-0.93, p less than 0.0001) simply on the basis of the measured arterial and central venous O2 tensions or saturations.

Adolescent↗
PubMed1987

[Comparison of ultrasound and radiology in the intraoperative diagnosis of nephrolithiasis].

Both intraoperative ultrasonography and radiology were utilized as a surgical aid while operating on 53 patients with renal lithiasis. A thorough comparison was made between the two imaging techniques: intraoperative US showed higher levels of sensitivity and accuracy, while specificity was maximal in intraoperative radiology. Intraoperative US proved to be a versatile and safe diagnostic procedure--as well as easy and quick to perform--whose accuracy in localizing stones as well as residual fragments appeared to be extremely high. Intraoperative US assistance during surgical procedures for renal lithiasis proves thus to be of the utmost importance in urologic practice.

Evaluation Studies as Topic↗