Biomedical subjects

Tommaso Fiore

Publications and source records attributed to Tommaso Fiore.

12 recordsLinked to original sources

PubMed2007

Use of N-terminal pro-brain natriuretic peptide to detect acute cardiac dysfunction during weaning failure in difficult-to-wean patients with chronic obstructive pulmonary disease.

OBJECTIVE: To evaluate the utility of serial measurements of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) to detect acute cardiac dysfunction during weaning failure in difficult to wean patients with chronic obstructive pulmonary disease. DESIGN: Prospective observational cohort study. SETTING: A 14-bed general intensive care unit in a university hospital. PATIENTS: Nineteen patients mechanically ventilated for chronic obstructive pulmonary disease exacerbation who were difficult to wean. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Cardiac and hemodynamic variables, arterial and central venous blood gas, breathing pattern, respiratory mechanics, indexes of oxygen cost of breathing, and plasma levels of NT-proBNP were measured and analyzed immediately before (baseline) and at the end of a spontaneous breathing trial. Eight of 19 patients (42%) were identified with acute cardiac dysfunction at the end of the weaning trial. Baseline NT-proBNP levels were significantly higher (median 5000, interquartile range 4218 pg/mL) in these patients than in patients without evidence of acute cardiac dysfunction (median 1705, interquartile range 3491 pg/mL). Plasma levels of NT-proBNP increased significantly at the end of the spontaneous breathing trial only in patients with acute cardiac dysfunction (median 12,733, interquartile range 16,456 pg/mL, p < .05). The elevation in NT-proBNP at the end of the weaning trial had a good diagnostic performance in detecting acute cardiac dysfunction, as estimated by area under the receiver operating characteristic curve analysis (area under the curve 0.909, se 0.077, 95% confidence interval 0.69-0.98; p < .0001, cutoff = 184.7 pg/mL). CONCLUSIONS: Serial measurements of NT-proBNP plasma levels provided a noninvasive manner to detect acute cardiac dysfunction during an unsuccessful weaning trial in difficult to wean patients with chronic obstructive pulmonary disease. The utility of this test as a complement of the standard clinical monitoring of the weaning trial deserves further investigation.

Acute Disease↗

PubMed2006

Jaundice in critical illness: promoting factors of a concealed reality.

OBJECTIVE: In critical illness, liver dysfunction (LD) is associated with a poor outcome independently of other organ dysfunctions. Since strategies to support liver function are not available, a timely and accurate identification of factors promoting LD may lead to prevention or attenuation of its consequences. The aim of this study was to assess risk factors for LD in critically ill patients. DESIGN: Prospective, observational study. SETTING: A multidisciplinary intensive care unit (ICU) of a university hospital. PATIENTS: All patients consecutively admitted over a 6-month period. INTERVENTION: None. MEASUREMENTS AND RESULTS: LD was defined as serum bilirubin levels >or=2 mg/dl and lasting for at least 48 h. Out of 283 patients, 141 matched inclusion criteria. Forty-four patients (31.2%) showed LD (LD group), while 97 (68.8%) were included in control group (C group). A binomial analysis showed that LD occurrence was associated with moderate (odds ratio [OR] 3.11; p=0.04) and severe shock (OR 3.46; p= 0.05), sepsis (OR 3.03; p=0.04), PEEP ventilation (OR 4.25; p=0.006), major surgery (OR 4.03; p=0.03), and gram-negative infections (OR 3.94; p=0.002). In stepwise multivariate analysis, the single independent predictive factors of LD resulted in severe shock (p=0.002), sepsis (p=0.03), PEEP ventilation (p=0.04), and major surgery (p=0.05). CONCLUSIONS: In critically ill patients jaundice is common, and severe shock states, sepsis, mechanical ventilation with PEEP and major surgery are critical risk factors for its onset. Since there is no specific treatment, prompt resuscitation, treatment of sepsis and meticulous supportive care will likely reduce its incidence and severity.

Aged↗

PubMed2006

Superior mesenteric artery blood flow modifications during off-pump coronary surgery.

BACKGROUND: Patients undergoing cardiac surgery are at increased risk of gut hypoperfusion. During off-pump surgery, hemodynamic derangements at the time of heart displacement could reduce splanchnic perfusion, outweighing the beneficial effects of avoiding cardiopulmonary bypass. The purpose of this study is to assess, prospectively, blood flow modifications in the superior mesenteric artery during off-pump surgery using transesophageal echocardiography. METHODS: In 19 patients undergoing multivessel elective off-pump coronary revascularization, systemic hemodynamics and superior mesenteric flow were assessed. Blood flow in the superior mesenteric artery was evaluated with duplex ultrasound using a transesophageal echo probe. Measurements were made four times: T0 (baseline), T1 (left anterior descendent anastomosis), T2 (heart displacement to expose the inferolateral and inferior walls), and T3 (closed chest, at the end of surgery). RESULTS: Superior mesenteric blood flow significantly decreased at T2 (from 426.4 +/- 83.1 mL to 212.9 +/- 48.6 mL, p < 0.001), when also cardiac output was reduced. The percentage of the cardiac output directed toward the mesenteric arterial bed was also decreased at this time. At the end of surgery (T3), whereas cardiac output returned to the initial values, mesenteric flow was significantly increased compared with baseline, with a higher percentage of the systemic output flowing through the superior mesenteric artery. CONCLUSIONS: Hemodynamic changes during off-pump coronary surgery induce a significant mesenteric hypoperfusion followed by a hyperemic response at the end of surgery. Transesophageal echo-Doppler allows the intraoperative measurement of blood flow distribution to splanchnic viscera.

Aged↗

PubMed2006

A comparison between fenoldopam and low-dose dopamine in early renal dysfunction of critically ill patients.

OBJECTIVE: Fenoldopam mesylate is a selective dopamine-1 agonist, with no effect on dopamine-2 and alpha1 receptors, producing a selective renal vasodilation. This may favor the kidney oxygen supply/demand ratio and prevent acute renal failure. The aim of the study was to investigate if fenoldopam can provide greater benefit than low-dose dopamine in early renal dysfunction of critically ill patients. DESIGN: Prospective, multiple-center, randomized, controlled trial. SETTING: University and city hospital intensive care units. PATIENTS: One hundred adult critically ill patients with early renal dysfunction (intensive care unit stay<1 wk, hemodynamic stability, and urine output or=1.5 mg/dL and 10% of the baseline value at the end of infusion, compared with only 46% in dopamine group (chi-square=4.06, p=.04). Total urinary output during drug infusion was not significantly different between groups. After 1 day, urinary output was lower in group F compared with group D (p<.05). CONCLUSIONS: In critically ill patients, a continuous infusion of fenoldopam at 0.1 microg/kg/min does not cause any clinically significant hemodynamic impairment and improves renal function compared with renal dose dopamine. In the setting of acute early renal dysfunction, before severe renal failure has occurred, the attempt to reverse renal hypoperfusion with fenoldopam is more effective than with low-dose dopamine.

Acute Kidney Injury↗

PubMed2006

Acoustic effects of positive end-expiratory pressure on normal lung sounds in mechanically ventilated pigs.

Computerized lung sounds analysis offers a new technique to monitor regional ventilation during spontaneous breathing. The purpose of the present study was to assess the acoustic behaviour of the respiratory system in healthy pigs during mechanical ventilation when a positive end-expiratory pressure (PEEP) is applied. Lung sounds were recorded during mechanical ventilation and different PEEP levels of 0, 5, 10, 15 and 20 cm H(2)O were applied. The increase in end-expiratory lung volume (EELV) related to the PEEP application was also measured and the correlation between changes in EELV (DeltaEELV) and sound amplitude (DeltaA) was examined. The amplitude of normal lung sounds was reduced by application of PEEP >or=10 cm H(2)O (P<0.05). The increase in PEEP from 0 to 20 cm H(2)O reduced the acoustic energy of lung sounds recorded at ZEEP by 0.3 dB (PEEP 5), 2 dB (PEEP 10), 5 dB (PEEP 15) and 7 dB (PEEP 20), which corresponds to 1%, 6%, 14% and 21% in acoustic attenuation, respectively. The variations in DeltaA correlated with changes in lung volume (P<0.05) and with changes in compliance of the respiratory system (P<0.05), but were not correlated with changes of the resistance of respiratory system. The frequency analysis showed a downward shifting of the spectra at frequencies between 150 and 600 Hz for PEEP levels >or=10 cm H(2)O and frequencies between 75 and 600 Hz for PEEP levels >or=15 cm H(2)O. The application of increasing levels of PEEP reduced the amplitude and changed the spectral characteristics of normal lung sounds.

Acoustics↗

PubMed2005

Cerebro-pulmonary interactions during the application of low levels of positive end-expiratory pressure.

OBJECTIVE: In patients with severe brain injury and acute lung injury the use of positive end-expiratory pressure (PEEP) is limited by conflicting results on its effect on intracranial pressure. We hypothesised that the occurrence of alveolar hyperinflation during the application of PEEP would lead to an increase in PaCO(2) responsible for a rise in intracranial pressure. DESIGN: Prospective interventional study. SETTING: Intensive Care Unit of University Hospitals. PATIENTS AND PARTICIPANTS: Twelve severely brain-injured patients with acute lung injury and intracranial pressure higher than applied PEEP. INTERVENTIONS: 5 and 10 cmH(2)O of PEEP was randomly applied. MEASUREMENTS AND RESULTS: In all patients intracranial pressure, flow velocity by transcranial Doppler of middle cerebral artery, and jugular oxygen saturation were recorded. Static volume-pressure curves of the respiratory system were obtained, recruited volume and elastance calculated to classify patients as recruiters and non-recruiters. In recruiters (= 6 patients), elastance decreased (P<0.01) and PaO(2) increased (P<0.005), while in non-recruiters (= 6 patients) elastance and PaCO(2) significantly increased (P<0.001). Intracranial pressure, Doppler flow velocity, and jugular saturation remained constant in recruiters but significantly increased (P<0.0001) in non-recruiters. A significant correlation was found between changes in intracranial pressure and elastance (r(2) = 0.8 P<0.0001) and between changes in PaCO(2) and intracranial pressure (P<0.001, r(2) = 0.4) and elastance (P<0.001, r(2) = 0.4), respectively. CONCLUSIONS: When PEEP induced alveolar hyperinflation leading to a significant increase in PaCO(2), intracranial pressure significantly increased, whereas when PEEP caused alveolar recruitment intracranial pressure did not change.

Adult↗

PubMed2005

Effects of high versus low positive end-expiratory pressures in acute respiratory distress syndrome.

A recent study by the Acute Respiratory Distress Syndrome Network compared the traditional lower end-expiratory pressure strategy with a higher end-expiratory pressure strategy in patients with the acute respiratory distress syndrome ventilated with low tidal volumes. Clinical outcomes were similar whether lower or higher positive end-expiratory pressure (PEEP) levels were used. We applied both the lower (9 +/- 2 cm H2O) and higher (16 +/- 1 cm H2O) PEEP strategy in 19 patients. In nine recruiters, the higher end-expiratory pressure strategy resulted in significant alveolar recruitment (587 +/- 158 ml), improvement in arterial oxygen partial pressure/inspired oxygen fraction ratio (from 150 +/- 36 to 396 +/- 138), and reduction in static lung elastance (from 23 +/- 3 to 20 +/- 2 cm H2O/L). In 10 nonrecruiters, alveolar recruitment was minimal, oxygenation did not improve, and static lung elastance significantly increased (from 26 +/- 5 to 28 +/- 6 cm H2O/L). The increase in oxygenation, the reduction in static lung elastance, and the shape of the volume-pressure curve during the lower PEEP strategy were independently associated with alveolar recruitment. In conclusion, the protocol proposed by the Acute Respiratory Distress Syndrome Network, lacking solid physiologic basis, frequently fails to induce alveolar recruitment and may increase the risk of alveolar overinflation.

Adult↗

PubMed2005

Hemodynamics in off-pump surgery: normal versus compromised preoperative left ventricular function.

OBJECTIVE: Off-pump coronary surgery (OPCABG), avoiding cardiopulmonary bypass and cardioplegic arrest, seems to be a better choice in patients with poor baseline cardiac function. Since cardiocirculatory collapse could be induced by heart displacement in this group of patients at high risk, a greater pathophysiologic understanding of the hemodynamic derangements occurring in such patients is needed. METHODS: Twenty-eight elective OPCABG patients were evaluated for hemodynamic changes induced by heart displacement, using arterial thermodilution to measure cardiac output and global end-diastolic volume. Hemodynamic parameters were recorded: at baseline; during proper exposure and stabilization of each vessel; and at the end of surgery. Patients were divided into two groups, according to baseline ejection fraction (EF): group A (EF>30%; N=16), group B (EF< or =30%; N=12). RESULTS: Heart displacement induced a significant drop in the cardiac and stroke index, with a lesser decrease of mean arterial pressure because of raised systemic vascular resistance. Preload, measured as global end diastolic volume, significantly decreased in group A, while it remained unchanged or increased in group B. Linear regression between the preload index and left ventricular stroke work was significant only in group A. CONCLUSIONS: Patients with poor baseline cardiac function can well tolerate OPCABG. However, the pathophysiologic modifications underlying the hemodynamic changes are different compared to those in patients with good preoperative cardiac performance.

Aged↗

PubMed2005

Brief hypoxia before normoxic reperfusion (postconditioning) protects the heart against ischemia-reperfusion injury by preventing mitochondria peroxyde production and glutathione depletion.

Several recent works have shown that a brief ischemia applied during the onset of reperfusion (postconditioning) is cardioprotective in different animal models and that the early minutes of reperfusion are critical to its cardioprotection. This effect has been related to prevention of oxidative stress, but mechanisms have not been clearly demonstrated. The present study tested the hypothesis that mitochondria play a central role in peroxide production and oxidative stress during reperfusion and are responsible for the protective effect of postconditioning. Isolated perfused rat hearts were subjected to complete global ischemia for 45 min and reperfused for 40 min. Normoxic group was reperfused with a Krebs-Henseleit solution with the preischemic pO2 level (600 mmHg); in the "hypoxic group," normoxic reperfusion was preceded by 3 min with 150 mmHg pO2. Reperfusion was stopped at 3 and 40 min. The rate of hydroperoxide production, GSH, GSSG, and carbonyl protein levels were measured in mitochondria at 3 min and at the end of reperfusion. GSH and GSSG were also measured in tissue. Hemodinamic function was monitored during the experiment. LVEDp increased and LVDp decreased in the normoxic group but not in the hypoxic group. The rate of mitochondrial peroxide production was higher in normoxic than in the hypoxic group 3 min after reperfusion and at its conclusion. Accordingly, GSH was oxidized in normoxic but not in hypoxic hearts. Mitochondria carbonyl proteins were significantly higher in normoxic than in the hypoxic group at the end of reperfusion. In this model, 1) hypoxic reperfusion at the onset of reperfusion reduces myocardial injury; 2) the major rate of mitochondrial peroxide production is 3 min after the onset of reperfusion; 3) cardioprotection of postconditioning correlates with reduced mitochondria peroxide production and prevention of GSH oxidation.

Animals↗

PubMed2004

Transesophageal echocardiography for diagnosis of traumatic aortic injury: an appraisal of the evidence.

BACKGROUND: An overview of the validity of transesophageal echocardiography (TEE) in patients suspected to have traumatic aortic injury (TAI). METHODS: Computerized bibliographic search of trials from 1994 to 2002 evaluating the use of TEE to confirm the diagnosis of TAI. Seven relevant studies out of 204 were identified, involving 758 patients. The accuracy of TEE was analyzed by constructing summary receiver-operating characteristic (sROC) curves and computing areas under the sROC curve. RESULTS: No prospective randomized trial was found. Although accuracy varied greatly, summary ROC curve found that TEE enjoyed a high diagnostic performance. Some study characteristics can affect accuracy. CONCLUSIONS: Our findings seems to indicate that TEE is a valuable tool for diagnosing TAI, and its use as first-line evaluation of such patients can be supported; however, given the lack of randomized trials, no standard of care can be drawn from the present overview: future studies should look at this problem more carefully, and should be methodologically rigorous.

Aorta↗

PubMed2003

Estimating respiratory system compliance during mechanical ventilation using artificial neural networks.

UNLABELLED: In this study we evaluated whether a technology based on artificial neural networks (ANN) could estimate the static compliance (C(RS)) of the respiratory system, even in the absence of an end-inspiratory pause, during continuous mechanical ventilation. A porcine model of acute lung injury was used to provide recordings of different respiratory mechanics conditions. Each recording consisted of 10 or more consecutive breaths in volume-controlled mechanical ventilation, followed by a breath having an end-inspiratory pause used to calculate C(RS) according to the interrupter technique (IT). The volume-pressure loop of the breath immediately preceding the one with pause was given to the ANN for the training, together with the C(RS) separately calculated by the IT. The prospective phase consisted of giving only the loops to the trained ANN and comparing the results yielded by it to the compliance separately calculated by the investigators. Determination of measurement agreement between ANN and IT methods showed an error of -0.67 +/- 1.52 mL/cm H(2)O (bias +/- SD). We could conclude that ANN, during volume-controlled mechanical ventilation, can extract C(RS) without needing to stop inspiratory flow. IMPLICATIONS: We studied the application of artificial neural networks (ANN) to the estimation of respiratory compliance during mechanical ventilation. The study was performed on an animal model of acute lung injury, testing the performance of ANN in both healthy and diseased conditions of the lung.

Air Pressure↗

PubMed2002

Immediate versus delayed endovascular treatment of post-traumatic aortic pseudoaneurysms and type B dissections: retrospective analysis and premises to the upcoming European trial.

BACKGROUND: Stent grafting has been reported as a viable therapeutic option for the delayed treatment of traumatic rupture of the aortic isthmus as well as reconstruction of thoracic aortic dissections. We tested the hypothesis of whether immediate endovascular management offers clinical and pathological advantages over a delayed approach in patients with post-traumatic aortic pseudoaneurysms (PAPs) and Stanford type-B dissections (TBDs). METHODS: Thirty-one consecutive patients who were admitted with diagnosis of either PAP (n=10; 33.4+/-8.7 years) or TBD (n=21; 58.2+/-8.4 years) were respectively divided into 2 groups according to the timing of diagnosis and endovascular treatment after the traumatic or pathologic event: immediate ([lteq]2 weeks; PAP=6 and TBD=7) and delayed (>2 weeks; PAP=4 and TBD=14). Excluder-Gore (11 in PAP and 8 in TBD) and Talent-Medtronic (1 in PAP and 7 in TBD) endovascular stent grafts were deployed. Follow-up was performed at 3 months, 6 months, and 1 year and based on laboratory tests; chest angio-computed tomography scans of chest, abdomen, and pelvis; and transesophageal echocardiography. RESULTS: The endovascular procedure proved uneventful in all PAP patients who underwent either immediate or delayed treatment. In 1 PAP patient with delayed treatment, surgical removal of the pseudoaneurysm was still necessary because of further compression of the airway stem. All immediately treated TBD patients were also successful. However, in 8 of 13 TBD patients with delayed treatment (61.5%), a stent graft deployment was not possible because of complicated progression of the false lumen and multiple intimal entry tears: 1 patient benefited by fenestrations of the false lumen and 7 patients underwent medical therapy. One patient (8.3%) died because of retrograde dissection involving the aortic arch. All patients treated with endovascular stent grafts were discharged within 5 days. CONCLUSIONS: An immediate endovascular management of PAP and TBD patients offers important advantages such as avoidance of high-risk surgical procedures and postoperative complications with short hospital stay. Moreover, it has been observed that an immediate endovascular treatment allows a safe management of all patients with complete healing of the aortic wall and regression of the pseudoaneurysm in the PAP group and thrombosis of the false lumen in TBD patients.

Adult↗