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Biomedical subjects

A Gasparetto

Publications and source records attributed to A Gasparetto.

At least 37 records · Page 2Linked to original sources
PubMed1997

Respiratory system mechanics in the early phase of acute respiratory failure due to severe kyphoscoliosis.

OBJECTIVE: To evaluate respiratory mechanics in the early phase of decompensation in a group of seven patients with severe kyphoscoliosis (KS) (Cobb angle > 90 degrees) requiring mechanical ventilatory support. DESIGN: Prospective clinical study with a control group. SETTING: General intensive care unit at University of Rome "La Sapienza". PATIENTS: Seven consecutive patients affected by severe KS in the early phase of acute decompensation and a control group of six ASA (American Society of Anesthesiology) 1 subjects who were mechanically ventilated during minor surgery. MEASUREMENTS AND RESULTS: Respiratory mechanics were evaluated during constant flow-controlled mechanical ventilation at zero end-expiratory pressure with the end-inspiratory and end-expiratory occlusion technique. In five patients who showed increased ohmic resistance (RRSmin), we evaluated the possibility of reversing this increase with a charge dose of 6 mg/kg doxophylline i.v. In four KS patients, in whom a reliable esophageal pressure was confirmed by a positive occlusion test, we separated respiratory system data into lung and chest wall component. All KS patients showed reduced values of respiratory compliance (CRS) and increased respiratory resistance (RRS). The average basal values of CRS were 36 +/- 10 vs 58 +/- 8.5 cmH2O in control patients; RRSmax was 20 +/- 3.1 vs. 4.5 +/- 1.2 cmH2O/1 per s; RRSmin 6.2 +/- 1.2 vs. 2 +/- 0.5 cmH2O/1 per s: delta RRS 14 +/- 2.6 cmH2O vs 2.4 +/- 0.7 cmH2O/1 per s. All KS patients showed low values of intrinsic positive end-expiratory pressure (PEEPi) (1.8 +/- 1.5 cmH2O). Separation of lung and chest-wall mechanics, performed only in four patients, showed a reduction in both lung (66.7 +/- 7.2 ml/cmH2O) and chest wall values (84 +/- 8.2 ml/cmH2O), while both RmaxL and RmaxCW were increased (16.6 +/- 2 and 2.8 +/- 0.4 cmH2O/1 per s, respectively). Infusion of doxophylline did not significantly change respiratory mechanics when evaluated 15, 30, and 45 min after the infusion. CONCLUSIONS: During acute decompensation, both lung and chest-wall compliance are severely reduced in KS patients: conversely, and, contrary to that in patients with chronic obstructive pulmonary disease, increases in airway resistance and PEEPi seem to play only a secondary role.

Airway Resistance↗
PubMed1997

Exogenous reactive oxygen species deplete the isolated rat heart of antioxidants.

The effects of reactive oxygen species (ROS) on myocardial antioxidants and on the activity of oxidative mitochondrial enzymes were investigated in the following groups of isolated, perfused rat hearts. I: After stabilization the hearts freeze clamped in liquid nitrogen (n = 7). II: Hearts frozen after stabilization and perfusion for 10 min with xanthine oxidase (XO) (25 U/l) and hypoxanthine (HX) (1 mM) as a ROS-producing system (n = 7). III: Like group II, but recovered for 30 min after perfusion with XO + HX (n = 9). IV: The hearts were perfused and freeze-clamped as in group III, but without XO + HX (n = 7). XO + HX reduced left ventricular developed pressure and coronary flow to approximately 50% of the baseline value. Myocardial content of hydrogen peroxide (H2O2) and malondialdehyde (MDA) increased at the end of XO + HX perfusion, indicating that generation of ROS and lipid peroxidation occurred. Levels of H2O2 and MDA normalized during recovery. Superoxide dismutase, reduced glutathione and alpha-tocopherol were all reduced after ROS-induced injury. ROS did not significantly influence the tissue content of coenzyme Q10 (neither total, oxidized, nor reduced), cytochrome c oxidase, and succinate cytochrome c reductase. The present findings indicate that the reduced contractile function was not correlated to reduced activity of the mitochondrial electron transport chain. ROS depleted the myocardium of antioxidants, leaving the heart more sensitive to the action of oxidative injury.

Animals↗
PubMed1997

Comparative evaluation of the cardiorespiratory effects of assist control ventilation vs pressure support ventilation in patients following orthotopic liver transplantation.

OBJECTIVE: 1) To compare the haemodynamic tolerance of ACV and PSV in patients mechanically ventilated after orthotopic liver transplantation; 2) to compare patients comfort during ACV and PSV. DESIGN: Prospective randomized cross-over study. SETTING: General ICU of the University of Rome "La Sapienza". PATIENTS: Eighteen patients admitted in ICU after orthotopic liver transplantation. MEASUREMENT AND RESULTS: Haemodynamic, oxygen transport and blood gas data were compared during an ACV and PSV trial (30'). A statistically significant decrease of mean pulmonary and systemic arterial pressure, PCOP, LVSWI, occurred during the PSV trial. PaO2 and DO2I decreased during PSV, but were still in supranormal range; 16 out of 18 patients described PSV as more comfortable. CONCLUSIONS: ACV and PSV provided a comparable haemodynamic tolerance in our patients, although during PSV the PaO2 was slightly decreased, probably due to decreased mean airway pressure (from 9.3 +/- 1.2 cmH2O during ACV to 6.6 +/- 1 cmH2O during PSV). PSV can be considered as a good alternative to the standard weaning techniques following orthotopic liver transplantation.

Adult↗
PubMed1996

Hemodynamic and metabolic effects of transjugular intrahepatic portosystemic shunt (TIPS) during anesthesia for orthotopic liver transplantation.

Recently, the transjugular intrahepatic portosystemic shunt (TIPS) has been advocated as a safe bridge to orthotopic liver transplantation (OLT). We retrospectively studied 53 consecutive cirrhotic patients who underwent OLT: 27 patients with TIPS were compared to 26 controls. Hemodynamic and oxyphoretic data (Fick method) were collected during six phases of OLT. There were no significant differences in demographic data and Child-Pugh class, nor in surgical time and blood product requirements before the anhepatic phase between TIPS patients and controls. In the TIPS group, we observed a marked hyperdynamic profile with a lower systemic vascular resistance index, higher cardiac index, and depressed oxygen consumption before native liver removal. During the same period, the TIPS group developed a greater acidosis and was treated with a larger amount of NaHCO3. Following the anhepatic phase, no differences between the two groups were detected. All transplantations were successful, and no complications related to TIPS were observed. These results seem to be the consequence of a reduced liver function reserve with a direct hemodynamic effect due to the TIPS.

Acidosis↗
PubMed1996

Early and late onset bacteremia have different risk factors in trauma patients.

OBJECTIVE: The aim of this study was to identify risk factors and to describe epidemiological patterns for early-(EOB) and late-onset bacteremias (LOB) after trauma. DESIGN: A prospective study conducted on 141 consecutive trauma patients. SETTING: A general intensive care unit (ICU) of a university hospital. PATIENTS: All multiple trauma patients admitted to our general intensive care unit (ICU) from December 1990 to May 1992 were prospectively enrolled in the study. The following information was collected for each patient and recorded in a computer database: demography, severity of trauma according to the Abbreviated Injury Scale (AIS), severity of coma according to the Glasgow Coma Scale (GCS), presence of pneumothorax, pulmonary contusion, rib fractures, hemothorax, and abdominal trauma, use of mechanical ventilation, and placement of central venous catheters. Bacteremias were defined as EOB when onset occurred within 96 h after trauma, and as LOB when appearing after 96 h from trauma. RESULTS: Thirty-seven patients developed bacteremia during their ICU stay (26%): 11 (29.7%) EOB and 26 (70.3%) LOB. Gram-positive cocci were isolated more frequently in EOB than in LOB (chi 2 = 4.1, P = 0.04). The risk of EOB was significantly increased by the presence of pulmonary contusion [relative risk (RR) 15.0; confidence interval (CI) 1.99-113.25], pneumonia before the onset of bacteremia (RR 3.56; CI 1.17-10.69), AIS score greater than 32 and an abdominal injury score greater than 9 (RR 3.11; CI 1.02-9.49), while intravascular catheters and mechanical ventilation did not represent risk factors for EOB. LOB had a very different pattern and their risk was significantly increased by exposure to intravascular catheters (RR 4.96; CI 1.23-19.94) and to mechanical ventilation lasting more than 7 days (RR 3.6; CI 1.6-8.1). CONCLUSIONS: Scoring with the AIS of the abdominal and thoracic trauma at admission to the ICU appears a useful tool for identifying trauma patients at increased risk of EOB. A rigorous policy of catheter placement and maintenance as a means of reducing late bacteremias in trauma patients is essential.

Abdominal Injuries↗
PubMed1996

O2 consumption-O2 delivery relationship and arteriolar resistance in the forearm of critically ill patients measured by near infrared spectroscopy.

Eight patients with severe sepsis, four with septic shock, and eight without sepsis were studied to investigate whether skeletal muscle influences the whole body O2 consumption (VO2)-O2 delivery relationship and hemodynamics. A forearm VO2-O2 delivery dependency was observed only in nonseptic patients, in whom no whole body VO2-O2 delivery dependency appeared. No forearm VO2-O2 delivery relationship was observed in septic and shock patients, in whom whole body VO2-O2 delivery dependency was found. In shock patients the lack of forearm VO2-O2 delivery dependency was associated with low forearm arteriolar resistance (FAR) even at a relatively low forearm blood flow (FBF). Neither a relationship between forearm VO2 and whole body VO2 nor between FAR and SVR was found in any groups of patients. Septic shock was associated with low FAR that was not affected by the FBF decrease, indicating that in this condition, hemodynamics could be influenced by skeletal muscle resistance.

Aged↗
PubMed1996

Bioavailability of a controlled release formulation of ursodeoxycholic acid in man.

Several controlled release formulations of ursodeoxycholic acid (UDCA) are currently available. However, none of these results in an optimal bioavailability of the active ingredient as a function of the absorption windows for bile acids found at the gastroduodenal level. Nonsaturated passive absorption of bile acids occurs at these sites, while absorption in the rest of the intestinal tract is less consistent as it is limited by the presence of carriers. These considerations led to the development of an original delayed-release formulation of UDCA using the bioadhesive technique. This allows a longer residence time at the appropriate sites and hence a higher passive absorption of UDCA. The results of this pharmacokinetic study, which compared the new formulation with a traditional pH-dependent sequential release formulation, demonstrated that the new formulation had a greater area under the curve (AUC) during a 24 h period, when compared with that of the reference drug, reaching statistically significant values (p < 0.01) within the first 12 h.

Adolescent↗
PubMed1995

Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease.

BACKGROUND: In patients with acute exacerbations of chronic obstructive pulmonary disease, noninvasive ventilation may be used in an attempt to avoid endotracheal intubation and complications associated with mechanical ventilation. METHODS: We conducted a prospective, randomized study comparing noninvasive pressure-support ventilation delivered through a face mask with standard treatment in patients admitted to five intensive care units over a 15-month period. RESULTS: A total of 85 patients were recruited from a larger group of 275 patients with chronic obstructive pulmonary disease admitted to the intensive care units in the same period. A total of 42 were randomly assigned to standard therapy and 43 to noninvasive ventilation. The two groups had similar clinical characteristics on admission to the hospital. The use of noninvasive ventilation significantly reduced the need for endotracheal intubation (which was dictated by objective criteria): 11 of 43 patients (26 percent) in the noninvasive-ventilation group were intubated, as compared with 31 of 42 (74 percent) in the standard-treatment group (P < 0.001). In addition, the frequency of complications was significantly lower in the noninvasive-ventilation group (16 percent vs. 48 percent, P = 0.001), and the mean (+/- SD) hospital stay was significantly shorter for patients receiving noninvasive ventilation (23 +/- 17 days vs. 35 +/- 33 days, P = 0.005). The in-hospital mortality rate was also significantly reduced with noninvasive ventilation (4 of 43 patients, or 9 percent, in the noninvasive-ventilation group died in the hospital, as compared with 12 of 42, or 29 percent, in the standard-treatment group; P = 0.02). CONCLUSIONS: In selected patients with acute exacerbations of chronic obstructive pulmonary disease, noninvasive ventilation can reduce the need for endotracheal intubation, the length of the hospital stay, and the in-hospital mortality rate.

Acute Disease↗
PubMed1995

Paralysis has no effect on chest wall and respiratory system mechanics of mechanically ventilated, sedated patients.

OBJECTIVE: To evaluate the separate effects of sedation and paralysis on chest wall and respiratory system mechanics of mechanically ventilated, critically ill patients. SETTING: ICU of the University "La Sapienza" Hospital, Rome. PATIENTS AND PARTICIPANTS: 13 critically ill patients were enrolled in this study. All were affected by disease involving both lungs and chest wall mechanics (ARDS in 4 patients, closed chest trauma without flail chest in 4 patients, cardiogenic pulmonary oedema with fluidic overload in 5 patients). MEASUREMENTS AND RESULTS: Respiratory system and chest wall mechanics were evaluated during constant flow controlled mechanical ventilation in basal conditions (i.e. with the patients under apnoic sedation) and after paralysis with pancuronium bromide. In details, we simultaneously recorded airflow, tracheal pressure, esophageal pressure and tidal volume; with the end-inspiratory and end-expiratory airway occlusion technique we could evaluate respiratory system and chest wall elastance and resistances. Lung mechanics was evaluated by subtracting chest wall from respiratory system data. All data obtained in basal conditions (with the patients sedated with thiopental or propofol) and after muscle paralysis were compared using the Student's t test for paired data. The administration of pancuronium bromide to sedated patients induced a complete muscle paralysis without producing significant modification both to the viscoelastic and to the resistive parameters of chest wall and respiratory system. CONCLUSIONS: This study demonstrates the lack of additive effects of muscle paralysis in mechanically ventilated, sedated patients. Also in view of the possible side effects of muscle paralysis, our results question the usefulness of generalized administration of neuromuscular blocking drugs in mechanically ventilated patients.

Adult↗
PubMed1995

Antioxidant activity of silybin in vivo during long-term iron overload in rats.

BACKGROUND & AIMS: Hepatic iron toxicity may be mediated by free radical species and lipid peroxidation of biological membranes. The antioxidant property of silybin, a main constituent of natural flavonoids, was investigated in vivo during experimental iron overload. METHODS: Rats were fed a 2.5% carbonyl-iron diet and 100 mg.kg body wt-1.day-1 silybin for 4 months and were assayed for accumulation of hepatic lipid peroxidation by-products by immunocytochemistry, mitochondrial energy-dependent functions, and mitochondrial malondialdehyde content. RESULTS: Iron overload caused a dramatic accumulation of malondialdehyde-protein adducts into iron-filled periportal hepatocytes that was decreased appreciably by silybin treatment. The same beneficial effect of silybin was found on the iron-induced accumulation of malondialdehyde in mitochondria. As to the liver functional efficiency, mitochondrial energy wasting and tissue adenosine triphosphate depletion induced by iron overload were successfully counteracted by silybin. CONCLUSIONS: Oral administration of silybin protects against iron-induced hepatic toxicity in vivo. This effect seems to be caused by the prominent antioxidant activity of this compound.

Adenosine Triphosphate↗
PubMed1995

Control of post anaesthetic shivering with nefopam hydrochloride in mildly hypothermic patients after neurosurgery.

Postoperative shivering may be prevented by maintaining normothermia intraoperatively or it may be treated using specific drugs. The aim of this study was to compare the efficacy of nefopam hydrochloride (nefopam) to that of clonidine and meperidine in patients undergoing elective neurosurgical procedures. Three groups of patients were included in the study. Patients in group A (60) received i.v., at random, 20 mg of nefopam, 50 mg of meperidine or 150 micrograms of clonidine in the immediate postoperative period. The incidence of shivering and the time at which shivering ceased were noted, along with central temperature and main haemodynamic changes. Group B (20) received i.v., at random, either 10 mg of nefopam or saline before awakening from anaesthesia. The effects of nefopam on central temperature, oxygen consumption (Vo2), carbon dioxide production (VcO2), basal metabolic rate (BMR) and energy expenditure (EE) were investigated. Group C (10) received i.v. 20 mg of nefopam during surgery: cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP) and electroencephalogram (EEG) were monitored. In group A nefopam stopped shivering in 95% of patients when compared to meperidine and clonidine, which were effective in 32% and 40% of patients respectively. In group B, only 10% of patients receiving nefopam had postoperative shivering, Vo2, VcO2 and EE were significantly lower in patients treated with nefopam than those in the control group. No changes in CSFP, CPP or EEG were observed in group C. In conclusion, nefopam seems to be more effective than clonidine or meperidine in quickly suppressing shivering, without producing significant adverse reactions.

Adult↗
PubMed1995

High IL-6 serum levels are associated with septic shock and mortality in septic patients with severe leukopenia due to hematological malignancies.

The serum levels of immunoreactive interleukin-6 (IL-6) and tumor necrosis factor (TNF) were analyzed in 14 leukopenic patients with documented sepsis, at 60 min (T0), 24 h (T1), and one week (T3) after the onset of sepsis syndrome. Sera from 10 leukopenic patients without sepsis (controls) were also tested. All septic patients had high IL-6 levels at T0. These levels persisted only in the seven patients who died of septic shock, presenting a 30-fold increase (p<0.001) as compared to the survivors and the controls. At T3, 7 survivors had recovered from sepsis and showed low IL-6 serum levels. The TNF serum concentration always <30 pg/ml in both the subjects and in the controls. The C-reactive protein (CRP) and clinical parameters appeared to be less specifically associated with shock and mortality than IL-6.

Adult↗
PubMed1995

[Anesthesia in experimental single-lung transplantation: hemodynamic and respiratory changes during prostaglandin E1 and nitroglycerin infusion].

INTRODUCTION: The haemodynamic and oxyforetic modifications induced by continuous infusion (c.i.) of Prostaglandin E1 (PGE1) and Nitroglycerin (NG) during experimental lung transplantation have been studied. METHODS: Twenty lung transplants have been performed on pigs (Landrace). Haemodynamic monitoring consisted of ECG, femoral cannulation for arterial pressure and Swan Ganz catheter. Continuous infusion of drugs started during pneumonectomy. Data have been collected in phase 1: after the induction of anaesthesia; in phase 2: 30 min after the start of pulmonary vasodilation in one lung ventilation with left pulmonary artery clamped; in phase 3: 30 min after lung revascularization; in phase 4: at the end of the surgery. The animals have been divided in two groups. Group A consisted of 10 cases treated with 50 ng/kg/min in phase 2 and 25 ng/kg/min in phase 3 and 4 of PGE1; group B consisted of 10 cases treated with 1 ncg/kg/min in phase 2 and 0.5 ncg/kg/min in phase 3 and 4 of NG. RESULTS: In phase 2 and 4 PA, RVSWI, PRVI increased in group B more than in group A (p < 0.05); in phase 3 PA, PAWP increased in group B more than in group A (p < 0.05). DISCUSSION: In our experience PGE1 has shown to be a stronger pulmonary vasodilator than NG. PGE1 can be considered the drug of choice for pulmonary vasodilation in experimental single lung transplantation, even if more investigations are needed for reaching the real goal of this procedure.

Alprostadil↗
PubMed1994

A new device to remove obstruction from endotracheal tubes during mechanical ventilation in critically ill patients.

OBJECTIVE: To evaluate the efficiency of a new device developed to remove obstructions from endotracheal tubes (ETT) in mechanically ventilated patients. DESIGN: Open study in mechanically ventilated sedated and paralyzed ICU patients. SETTING: General ICU and Laboratory of Respiratory Mechanics of the University of Rome "La Sapienza". PATIENTS: 8 consecutive unselected mechanically ventilated, critically ill patients in which a partial obstruction of ETT was suspected on the basis of an increase of the peak inspiratory pressure (> 20%) plus the difficult introduction of a standard suction catheter. INTERVENTIONS: Obstructions to ETT were removed with an experimental "obstruction remover" (OR) MEASUREMENTS: "In vivo" ETT airflow resistance (0.25; 0.5; 0.75; 11/s) was evaluated before and after use of the OR; the work of breathing necessary to overcome ETT resistance (WOBett) was also evaluated before and after OR use. RESULTS: The use of OR significantly reduced in all patients the ETT "in vivo" resistance (From 5.5 +/- 2.3 to 2.9 +/- 0.5 cmH2O/l/s at 0.25 l/s, p < 0.05; from 9 +/- 2.4 to 3.8 +/- 0.8 cmH2O/l/s at 0.5 l/s; from 12.2 +/- 3.5 to 5.7 +/- 1.2 cmH2O/l/s at 0.75 l/s; from 16.9 +/- 6 to 9.3 +/- 3.8 cmH2O/l/s at 1 l/s, p < 0.01 respectively). Also the WOBett was significantly reduced after use of the OR (from 0.66 +/- 0.19 to 0.34 +/- 0.08 J/l; p < 0.05). CONCLUSION: this experimental device can be safely and successfully used to remove obstructions from the ETT lumen, without suspending mechanical ventilation, reducing the need for rapid ETT substitution in emergency and life-threatening situations.

Adult↗
PubMed1994

Evaluation of respiratory system resistance in mechanically ventilated patients: the role of the endotracheal tube.

OBJECTIVE: To investigate the role played by the endotracheal tube (ETT) in the correct evaluation of respiratory system mechanics with the end inflation occlusion method during constant flow controlled mechanical ventilation. SETTING: General ICU, university of Rome "La Sapienza". PATIENTS: 12 consecutive patients undergoing controlled mechanical ventilation. METHODS: We compared the values of minimal resistance of the respiratory system (i.e. airway resistance) (RRS min) obtained: i) subtracting the theoretical value of ETT resistance from the difference between P max and P1, measured on airway pressure tracings obtained from the distal end of the ETT; ii) directly measuring airway pressure 2 cm below the ETT, thus automatically excluding ETT resistance from the data. RESULTS. The values of RRS min obtained by measuring airway pressure below the ETT were significantly lower than those obtained by measuring airway pressure at the distal end of the ETT and subtracting the theoretical ETT resistance (4.5 +/- 2.8 versus 2.5 +/- 1.6 cm H2O/l/s, p < 0.01). CONCLUSION: When precise measurements of ohmic resistances are required in mechanically ventilated patients, the measurements must be obtained from airways pressure data obtained at tracheal level. The "in vivo" positioning of ETT significantly increases the airflow resistance of the ETT.

Acute Disease↗