Biomedical subjects

R Luzietti

Publications and source records attributed to R Luzietti.

8 recordsLinked to original sources

PubMed2002

Cerebral hemodynamics and fetal behavioral states.

OBJECTIVE: This study aimed to evaluate the hemodynamic patterns of the proximal (M1) and distal (M2) portions of the middle cerebral artery, during different fetal behavioral states. DESIGN: The study included 20 normal singleton pregnancies at between 36 and 40 weeks of gestation. After identification of the fetal behavioral state (FBS), flow velocity evaluation was performed on the proximal and distal segments of the middle cerebral artery during 'quiescence' (FBS-1F) and 'activity' (FBS-2F). RESULTS: A statistically significant decrease of pulsatility index, reflecting a decrease of impedance to flow values, was identified in both segments of the middle cerebral artery (MCA) during 'activity', with a more marked decrease in the MCA-M2 than in MCA-M1 (M1, P = 0.0028; M2, P = 0.00000085). The mean fetal heart rate during 'quiescence' was significantly lower than during 'activity' (P = 0.0047). However, there was no significant correlation between the pulsatility index of both segments of the middle cerebral artery and the fetal heart rate during different fetal behavioral states. CONCLUSIONS: The results of this study provide evidence of the influence of different fetal behavioral states on fetal cerebral hemodynamic patterns. We believe it is better to sample the proximal segment in clinical practice because it is less influenced by fetal behavioral state. This information should be considered when evaluating fetal cerebral hemodynamics.

Adult↗

PubMed2001

Monitoring of antepartum and intrapartum fetal hypoxemia: pathophysiological basis and available techniques.

The challenge of obstetric surveillance is to identify those fetuses whose physiological defence mechanisms are compromised, in order to be able to act before decompensation has occurred. During the antenatal period, the evaluation of fetal hemodynamic adaptation to hypoxemia and the assessment of its chronological evolution by Doppler technology are crucial. During the intrapartum period, the relative inaccessibility of the fetus and the complexity of the pathophysiology of fetal oxygenation make it difficult to obtain and interpret information on the fetal response to labor stress. Due to the limitations of cardiotocography, additional information is required for appropriate decision making during labor. Current evidence suggests that modern technology applied to fetal surveillance can provide useful additional information that can improve our capacity to interpret fetal reactions to labor events.

Adaptation, Physiological↗

PubMed2001

The ten commandments in multiple pregnancies.

Multiple pregnancy represents a challenge for obstetrics and also poses significant psychological, social and economic problems. The chances of a successful outcome may be improved by appropriate preventive, diagnostic and management strategies, by the availability of specific skills and experience and by a multidisciplinary approach. In this paper are indicated and discussed, on the basis of current evidences, what can be considered the ten "commandments" in terms of providing optimal care in multiple pregnancies. In particular in this review we focus on the following topics: psychological support and clinical counseling; diagnosis and characterization of chorionicity; management at referral centers; individualization of care; avoidance of most frequent complications; consideration of specific pathologies; evaluation of fetal anatomy; monitoring of fetuses; planning of time and mode of delivery; monitoring of the mother during postpartum.

Delivery, Obstetric↗

PubMed1999

European Community multi-Center Trial "Fetal ECG Analysis During Labor": ST plus CTG analysis.

This report form part of the European Community Multi-Center Trial "Fetal ECG Analysis during Labor". Aim of this prospective trial was to identify changes in the fetal ECG waveform with cases of verified fetal hypoxia. In this paper we also report on the use of a newly developed automatic system for identification of ST waveform changes (ST Log). All ECG were recorded with the STAN recorder (Neoventa Medical AB, Gothenburg, Sweden). The ECG information was not displayed during labor in order not to influence the clinical management. This report includes data from 320 cases and include six cases of fetal intrapartum hypoxia. Twenty seven cases showed changes in ST waveform. All five cases with the most marked ST change (a rise in T/QRS of > 0.10 units and lasting more then 10 minutes) had signs of ongoing intrapartum hypoxia. Six out of six cases with evidence of intrapartum asphyxia, showed ST changes. On the basis of our multi-center trial it appears that the combined analysis of CTG and ST waveform changes provides an accurate way to identify adverse events during labor. The work is continuing with a new STAN recorder developed by Neoventa Medical in Göteborg and currently being tested in a Swedish randomized, controlled multi-center trial.

Acid-Base Equilibrium↗

PubMed1997

European Community Multicentre Trial "Fetal ECG Analysis During Labour": the P-R interval.

The aim of the European Community Multicentre Trial on Fetal ECG Analysis During Labour was to collect a clinical database of electrocardiograms on which the different patterns of ST waveform and time interval changes, so far identified, could be studied. The aim of this paper was to study the PR-RR relationship and the P wave patterns during normal labour. One thousand three hundred fifty accelerations and 350 decelerations were analysed in 618 labours, all with normal fetal outcome. All ECGs were recorded with the STAN recorder and linked to a PC system for data acquisition and analysis. A positive relationship between P-R and R-R intervals was identified in all reactive fetal heart rate traces. A P-R shortening was identified also with all decelerations of more than 40 bpm from the baseline, resulting in a negative PR-RR relationship. Experimental works have described a P-R shortening concurrent with the maximal R-R lengthening during acutely induced hypoxemia in fetal lambs. In our study normal cord acid-base status indicated that the majority of bradycardia episodes recorded were not related to acute hypoxemia: PR-RR relationship changes seem therefore to indicate an intact physiological fetal heart adaptive response to rapid change in the environment of either hypoxemic or haemodynamic origin. A negative PR-RR relationship by itself seems to be nothing more than an indicator of decelerations during labour and seems unable to discriminate between decelerations of different origin. Finally the P wave was no longer detectable during decelerations of more than 800 msec: in this situation the P-R interval can not be reliably measured.

Electrocardiography↗

PubMed1994

The fetal electrocardiogram: ST waveform analysis during labour.

Intrapartum fetal surveillance is still under debate, despite 30 years of clinical experience and numerous clinical trials. Waveform analysis of the fetal electrocardiogram has emerged not as an alternative to cardiotochography but as a support tool to allow more accurate interpretation of intrapartum events. During hypoxia, the healthy fetus is utilizing a series of defense mechanisms. Among these, the increase in sympathetic activity, with an increase in circulating adrenaline, activates the myocardium with an increase in workload (the product of cardiac output, myocardium contractility and blood pressure). If there is an imbalance between myocardial oxygen supply and consumption, determined by the workload, then anaerobic metabolism, with a breakdown of myocardial glycogen stores starts and high T waves emerges. ST depression with negative T waves has recently been observed during hypoxia experiments in experimentally growth retarded guinea pigs whilst their normally grown littermates showed ST elevation. These findings have stimulated the development of a dedicated fetal ECG monitor - STAN - incorporating both standard CTG and ST waveform analysis. The STAN concept has now been taken through the process of recognized validation including several prospective studies and a large randomized trial in Plymouth of 2400 high risk, term deliveries. The T/QRS ratio is only one parameter to be used - equally important is to identify the occurrence of ST depression with biphasic negative T waves and to interrelate the CTG and the ST waveform as outlined in the clinical guidelines (table I). This table contains the clinical experience gained over many years and has formed the basis for the first randomized controlled trial comparing ST waveform + CTG with CTG only. Obviously, when the T/QRS ratio is used as the only component of such a scheme, confusion emerges. The analysis should also contain cases with significant intrapartum hypoxia. Recent findings indicate that only when cord artery pH falls below 7.0 and when there is substantial metabolic acidemia is there a significant risk of intrapartum asphyxia. Metabolic acidemia should be estimated from base deficit in the extracellular fluid and the combination of cord artery and vein data should allow for a more accurate assessment of intrapartum events, including the assessment of the duration of hypoxia. The Plymouth trial has tested the hypothesis that the combination of ST wave form and CTG analysis compared with CTG analysis only would reduce operative interventions for fetal distress without placing the fetus at a risk.(ABSTRACT TRUNCATED AT 400 WORDS)

Electrocardiography↗

PubMed1992

Neonatal complications and risk of intraventricular-periventricular hemorrhage.

We have prospectively studied 117 premature infants < or = 1500 gm (VLBW) to assess the relationship between maternal, obstetric, fetal and newborn complications and the grade of periventricular-intraventricular hemorrhage (PVH-IVH). PVH-IVH was documented by cranial ultrasonography in 41% of surviving neonates. 83% of infants with PVH-IVH grade I-II survived as compared to the 39% of infants with PVH-IVH grade III-IV (p < .001). Maternal and obstetric complications were not associated with PVH-IVH (NS). Newborn respiratory complications (p < .004) and major infections (p < .02) are independent variables associated with PVH-IVH. Immaturity at delivery, metabolic acidosis, respiratory distress syndrome and recurrent apnea are important mechanisms of cerebral injury contributing to severity of PVH-IVH.

Acid-Base Equilibrium↗

PubMed1987

Prevalence of brain atrophy in liver cirrhosis patients with chronic persistent encephalopathy. Evaluation by computed tomography.

Brain computerized axial tomography scans were performed in 18 consecutive liver cirrhosis patients with chronic persistent encephalopathy (8 alcoholic and 10 nonalcoholic) in order to evaluate the incidence of brain atrophy in this pathological condition. Fifteen patients of similar age with liver cirrhosis of Child's class B but with acute episodic hepatic encephalopathy were studied in parallel. Brain atrophy was detected in 87.5% of alcoholic and in 50% of nonalcoholic liver cirrhosis patients with chronic persistent encephalopathy, whereas the patients with acute episodic encephalopathy were normal. The high frequency of brain atrophy in alcoholic patients with chronic encephalopathy can be attributed at least in part to the toxic effect of alcohol. The presence of brain atrophy in nonalcoholic liver cirrhosis patients with chronic persistent encephalopathy seems to indicate that the chronic exposure to toxins which are involved in the pathogenesis of hepatic encephalopathy leads to neuronal alterations which develop mainly in the cortex and which can be demonstrated by in vivo imaging only in a long-lasting state of coma. Moreover, alcohol and toxins causing hepatic encephalopathy seem to potentiate each other in inducing brain atrophy.

Adult↗