Biomedical subjects

Anna Cavallini

Publications and source records attributed to Anna Cavallini.

12 recordsLinked to original sources

PubMed2006

Defect distribution along single GaN nanowhiskers.

In this letter we report on spectral photoconductivity (PC) on different sections of single MBE-grown GaN nanowhiskers of diameters ranging on the order of 100 nm. The photoconductivity spectra show, besides the band-gap related transition, deep-levels corresponding to the yellow, green, and blue bands. A strong spatial localization of specific photocurrent peaks has been observed, indicating that the defects responsible for such transitions are distributed inhomogeneously along the column growth direction.

Electric Conductivity↗

PubMed2006

Impaired blood pressure increase in acute cardioembolic stroke.

BACKGROUND AND PURPOSE: Studies on the prognostic significance of blood pressure (BP) increases during the acute phase of ischemic stroke give contradictory results. The aim of this study was to evaluate BP response during the acute phase in different ischemic stroke subtypes, and to assess the prognostic value, considering long-term outcome, of different BP patterns recorded. METHODS: We included 110 ischemic stroke patients hospitalized within 6 h of the onset of symptoms. All the patients underwent 24-h monitoring on hospital admission and on day 7 after stroke. For statistical analysis the whole population was divided into cardioembolic (CE), atherothrombotic (AT) and lacunar (LAC) groups, according to TOAST (Trial of Org 10172 in Acute Stroke Treatment) criteria. RESULTS: In both the whole population and in all subgroups systolic and diastolic BP were higher at admission than during monitoring on day 7, the lowest values being recorded in the CE subgroup. CE stroke was significantly related to lower BP (systolic and diastolic) values (P = 0.01) during the acute phase and CE patients were characterized by poorer outcome. A history of diabetes was a predictor of higher systolic and diastolic BP on the first day of monitoring; higher systolic and diastolic BP values were related to a history of hypertension and with male gender, respectively. Predictors of death by 6-months were atrial fibrillation, age and history of hypertension (P < 0.05) while higher systolic BP in the acute phase seems to represent a protective factor. CONCLUSION: CE stroke shows a lack of BP response during the acute phase of ischemic stroke. This phenomenon is associated with a poor long-term outcome and seems not be related with cardiac co-morbidity.

Adult↗

PubMed2005

Cardiovascular risk calculators: understanding differences and realising economic implications.

In recent years, the concept of "global cardiovascular risk assessment" has grown in interest for its role in primary prevention of cardiovascular diseases. Interventions for reducing the risk of relapse for persons with cardiovascular past history are well agreed-on. But for persons without such a history, the risk of a first attack varies greatly and this variability implies a range in the intensity of interventions. In several countries, guidelines for general practitioners have been diffused about pharmaceutical prescriptions in the different risk classes. In particular, in Italy, a governmental drug management commission has established that Statins, the most used cholesterol lowering medicines, can be refunded by the National Healthcare System only if they are prescribed to hyper-cholesterol patients with a global risk greater than 20%. The question is: how to calculate the risk? We performed a review of both the web and the literature and we found a lot of different "risk calculators". By means of a simulation study, we showed that these tools, when used for the same person, may lead to very different results. We estimated the economic impact of using one or another calculator.

Aged↗

PubMed2004

Economic benefit from clinical practice guideline compliance in stroke patient management.

BACKGROUND AND PURPOSE: In a previous study we showed that compliance with evidence-based guidelines improves the health outcome of stroke patients in terms of both survival and residual disability. In this analysis, we shall investigate the impact of such guidelines on healthcare costs during the acute/sub-acute hospitalisation phase. METHOD: we considered the direct costs from the hospital's point of view, where funding is provided by the National Healthcare System. We did not consider production loss or intangible costs related to the decreased quality of life. Data was collected on both costs and guideline compliance prospectively, and the relationship between them was studied through a multivariate statistical model. RESULTS: Patients treated according to guidelines result in lower costs; on average they have a shorter length of stay in hospital (10.8 versus 12.9 days), leading to a significant difference in the consumption of hospital resources. On a level of statistical analysis, guideline compliance is a significant independent indicator of cost, together with the patient's initial disability and neurological deficit.

Aged↗

PubMed2004

Non-compliance with guidelines: motivations and consequences in a case study.

Guidelines are often based on a mixture of evidence-based and consensus-based recommendations. It is not straightforward that providing a series of "good" recommendations result in a guideline that is easily applicable, and it is not straightforward that acting according to such recommendations leads to an effective and efficient clinical practice. In this paper we summarize our experience in evaluating both the usability and the impact of a guideline for the acute/subacute stroke management. A computerised version of the guideline has been implemented and linked to the electronic patient record. We collected data on 386 patients. Our analysis highlighted a number of non-compliances. Some of them can be easily justified, while others depend only on physician resistance to behavioural changes and on cultural biases. From our results, health outcomes and costs are related to guideline compliance: a unit increase in the number of non-compliance results in a 7% increase of mortality at six months. Patients treated according to guidelines showed a 13% increase in treatment effectiveness at discharge, and an average cost of 2929 Euros vs 3694 Euros for the others.

Costs and Cost Analysis↗

PubMed2003

Role of monitoring in management of acute ischemic stroke patients.

BACKGROUND AND PURPOSE: Although several studies have demonstrated the effectiveness of specialist Stroke Unit (SU) care of stroke patients, there is still disagreement over how these units are best organized. We sought to clarify the role of continuous monitoring of physiological parameters in acute ischemic stroke. METHODS: We conducted a prospective study of 268 first-ever ischemic stroke patients admitted to our Cerebrovascular Department and allocated, according to the availability of beds, to the SU or Cerebrovascular Unit (CU). Statistical analysis compared mortality and outcome at discharge, medical and neurological complications, and length of hospitalization in the 2 care settings. RESULTS: Two hundred sixty-eight patients were enrolled. A good outcome at discharge, observed in 114 SU patients (85%) and 78 CU patients (58%) (odds ratio, 2.63; 95% CI, 1.4 to 4.8; P<0.02), was found, on multivariate analysis, to be significantly related to type of care (SU versus CU). A significantly greater proportion of SU patients showed adverse changes in monitored parameters, which required acute medical treatment (SU: 64%; CU: 19%; P<0.0001). The mean duration of these complications was significantly shorter in the SU patients (SU: 1.0 day; CU: 2.4 days; P<0.02), and the outcome in patients experiencing complications covered by the monitoring protocol was significantly better in the SU (66%) than in the CU (35%) group (P<0.0001). CONCLUSIONS: Admission of acute stroke patients to a monitoring SU may positively influence their outcome at discharge. Confirmation of our findings in larger trials will indicate the need for a revision of the minimum requirements of SUs, with the addition of monitoring as a new requirement.

Acute Disease↗

PubMed2003

Cardiovascular risk calculators: understanding differences and realising economic implications.

In recent years, the concept of "global cardiovascular risk assessment" has grown in interest for its role in primary prevention of cerebro-cardiovascular diseases. Interventions for reducing the risk of relapse for persons with past history of these diseases are well agreed-on. On the contrary, the risk status of persons without such a history varies greatly, and this variability implies a range in the intensity of interventions. In several countries, guidelines for general practitioners have been diffused about pharmaceutical prescriptions in presence of various risk degrees. In particular, in Italy, a governmental drug management commission has established that statins, the most used cholesterol lowering medicines, can be refunded by the National Healthcare System only if prescribed to hyper-cholesterol patients with a global risk greater than 20%. The question is: how to calculate the risk? We performed a review of both the web and the literature and we found a lot of different "risk calculators". By means of a simulation study, we showed that these tools, when applied to the same person, may lead to very different results. We estimated the economic impact of using one or another calculator.

Algorithms↗

PubMed2003

Web-based data and knowledge sharing between stroke units and general practitioners.

We describe a telemedicine application for emergency management in Stroke Units, where prompt decisions must be taken, often knowing neither the clinical history nor the stroke symptoms onset modality. We have designed and implemented an Information and Communication Technology architecture for the situation in which a general practitioner is called for a suspected stroke and provides for the admission to a Stroke Unit. By means of a palmtop and a wireless Internet connection, he can send to the Stroke Unit the demographic data, the list of the patient's problems, current and/or recent therapies, and a guideline-based stroke-specific form with the objective examination results. In this way, the Stroke Unit team is alerted and informed before the patient arrival, and can manage the urgency at the best. The proposal involved 20 general practitioners and one Stroke Unit in the Lombardia Region, Italy.

Computer Systems↗

PubMed2002

Guideline compliance improves stroke outcome: a preliminary study in 4 districts in the Italian region of Lombardia.

BACKGROUND AND PURPOSE: Guidelines for medical practice in stroke have been proposed in different countries, but their impact on stroke outcome has not been verified to date. The aim of this study was to evaluate the impact of the American Heart Association guidelines for acute stroke and for transient ischemic attack on first-ever stroke patients. METHODS: Three hundred eighty-six first-ever ischemic stroke patients were admitted to the study. Those observed within 6 hours from stroke onset were eligible for the acute clinical phase of the study, while all were admitted to the early clinical phase. The follow-up lasted 6 months. Primary end points were survival and the effectiveness of treatment on disability, measured as the proportion of potential improvement in the Barthel Index score achieved during treatment. A rating of noncompliance with the guideline recommendations was calculated for each patient, and its association with the end points was investigated. The Kaplan-Meier method and log-rank test were used to estimate and compare survival curves between groups; Cox proportional hazards model and logistic regression were used to identify risk factors for mortality; and correlation tests and regression analysis were used to evaluate the influence of guideline compliance on disability. Both univariate and multivariate statistical analyses were performed. RESULTS: Survival and treatment effectiveness were directly correlated with guideline compliance. The relative risk of death for patients with a noncompliance rating > or =5 was 2.26 with respect to patients with a noncompliance rating <5 (95% CI, 1.51 to 4.67; P<0.0007). In this latter group, at 6 months we detected a 15% decrease in mortality (95% CI, 9.1% to 17.5%). Treatment effectiveness showed a Spearman's rank correlation with the noncompliance rating of -0.3 (P<0.001). At discharge we observed a 13% increase in treatment effectiveness, while no significant differences were detectable at 3 and 6 months. These associations were confirmed by the multivariate analysis, in which we included, together with the noncompliance rating, all the variables previously identified as independent predictors of mortality and disability. CONCLUSIONS: This study demonstrates an association between adherence to guidelines and stroke outcome, and it can be viewed as a study that prepares the way for a randomized controlled trial in this area. It also emphasizes the need to develop personnel and structures devoted to stroke care because an evidence-based clinical approach could significantly reduce the risk of death.

Aged↗

PubMedDate not supplied

Visual acuity in the first two years of life in healthy term newborns: an experience with the teller acuity cards.

Teller Acuity Cards are a new "preferential looking" procedure for the evaluation of visual acuity in newborns and infants. We used this test to assess, longitudinally, visual acuity in 60 healthy term newborns followed up from birth to two years of age. In order to have a set of comparison parameters for use in studies of newborns at risk of developing visual system impairment, the relative maturational curve was plotted. The acuity values of our sample are in line with those reported by other authors in the literature and they represent the first set of such data referring to a group of healthy term newborns in Italy. This paper provides a visual acuity curve for the first two years of life obtained from healthy term newborns, a curve which could prove useful for reference when this technique is used on newborns at risk of developing neurological and especially visual problems.

Child, Preschool↗

PubMedDate not supplied

Cerebral haemodynamic response to acute intracranial hypertension induced by head-down tilt.

The aim of this study was to evaluate, in a context of general inhibition of the sympathetic nervous system, the cerebral haemodynamic response to -30 degrees head-down tilt (HDT), a manoeuvre that produces an increase in intracranial arterial pressure. Nineteen healthy subjects were studied according to the following protocol: 10 min lying in supine position, 10 min HDT, 10 min recovery. Inhibition of the sympathetic system was confirmed by the decrease in heart rate (-3.6 bpm) and arterial blood pressure (-5.9 mmHg, p<0.05) in the late phase of the test. Blood velocity and blood pusatility index initially increased (+3.2 cm s(-1) and +9% respectively, p<0.01) then returned towards baseline before the end of HDT, while the cerebrovascular resistance index (=arterial blood pressure/blood velocity) dropped significantly and remained below control level (-7%, p<0.01) throughout the test. The changes in both these indices were opposite to those reported in several sympathetic activation tests, such as the handgrip and cold pressor tests. Conversely, arterial pressure at cranial level increased during HDT (as it also does during sympathetic activation tests), due to the development of a hydrostatic pressure gradient between heart and brain levels. Therefore, the effects observed on the pulsatility and resistance indices are not secondary to the increase in intracranial arterial pressure. It is suggested that the changes in these cerebrovascular indices are mediated by a reduction of sympathetic tone that presumably involves the cerebral as well as the peripheral vascular bed.

Adaptation, Physiological↗

PubMedDate not supplied

A questionnaire on sleep behaviour in the first years of life: preliminary results from a normative sample.

The authors developed a questionnaire in Italian for investigating sleep problems in infants and toddlers. Applying the questionnaire, they conducted an exploratory investigation into the sleep behaviour of a sample of normal children during their first three years of life in order to gather preliminary data regarding the ease of use of the instrument. The questionnaire and the results of its first application (in an Italian sample of 50 healthy children aged 10-39 months) are presented. The results provide interesting information on the sleep behaviour of the young children in our sample and prompt reflections in relation to the instrument employed. The sleep behaviour questionnaire emerged, above all, as easy to use and readily comprehensible to those participating in this research study. Furthermore, it provided parents with an opportunity to reflect upon their child and his/her rhythms (in particular sleep-wake rhythms) and upon their own ability to manage these rhythms. This instrument seems, on the basis of these preliminary data, to allow the tracing of a well-defined and complete picture of the sleep behaviour of the healthy child in the first years of life.

Adult↗