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Biomedical subjects

A Bernardini

Publications and source records attributed to A Bernardini.

At least 19 recordsLinked to original sources
PubMed2005

Effect of tidal volume and respiratory rate on the power of breathing calculation.

BACKGROUND: The power of breathing (PoB) is used to estimate the mechanical workload of the respiratory system. Aim of this study was to investigate the effect of different tidal volume-respiratory rate combinations on the PoB when the elastic load is constant. In order to assure strict control of the experimental conditions, the PoB was calculated on an airway pressure-volume curve in mechanically ventilated patients. METHODS: Ten patients received three different tidal volume-respiratory rate combinations while minute ventilation was constant. Respiratory mechanics, PoB and its elastic and resistive components were calculated. Alternative methods to estimate the elastic workload were assessed: elastic work of breathing per litre per minute, elastic workload index (the square root of elastic work of breathing multiplied by respiratory rate) and elastic double product of the respiratory system (the elastic pressure multiplied by respiratory rate). RESULTS: Despite constant elastance and minute ventilation, the elastic PoB showed an increment greater than 200% from the lower to the greater tidal volume, accounting for approximately 80% of the whole PoB increment. On the contrary, elastic work of breathing per litre per minute, elastic workload index and elastic double product did not change. CONCLUSION: Changes in breathing pattern markedly affect the PoB despite constant mechanical load. Other indexes could assess the elastic workload without tidal volume dependence. Power of breathing use should be avoided to compare different mechanical loads or efficiencies of the respiratory muscles when tidal volume is variable.

Aged↗
PubMed2004

Effect of breathing pattern on the pressure-time product calculation.

BACKGROUND: The pressure-time product (PTP) is often used to compare conditions with different breathing patterns. Being the pressure-time product calculated with pressures changes over a minute, mechanical load and inspiration time per minute should be its main determinants. The aim of this study was to investigate if the method of PTP computation is affected by the breathing pattern when mechanical load and inspiratory time per minute are constant. METHODS: Respiratory mechanics and the PTP developed by the ventilator were calculated in 10 mechanically ventilated patients at three different respiratory rate/tidal volume combinations, provided that minute ventilation and inspiratory time per minute were constant. RESULTS: The static elastance did not change at different tidal volumes. Despite the constant elastic load over a minute, the elastic PTP showed an increment greater than 200% from the higher to the lower respiratory rate, responsible for approximately 80% of the whole PTP increment. On the contrary a 'corrected' elastic PTP (calculated using the square root of the elastic pressure-time area), the elastic double product of the respiratory system and the mean elastic pressure per minute, did not significantly change. CONCLUSIONS: Changes in breathing pattern markedly affected the PTP independently by the mechanical load and the inspiratory time per minute. In these conditions it could not correctly estimate the metabolic cost of breathing. The use of a 'corrected' PTP, the mean inspiratory pressure per minute or the double product of the respiratory system, could overcome this limitation.

Aged↗
PubMed2003

Resistive load of laryngeal mask airway and ProSeal laryngeal mask airway in mechanically ventilated patients.

BACKGROUND: The ProSeal Laryngeal Mask Airway (PLMA) ventilation tube is narrower and shorter than the standard Laryngeal Mask Airway (LMA) and is without the vertical bars at the end of the tube. In this randomized, crossover study, PLMA and LMA resistances were compared. METHODS: Respiratory mechanics was calculated in 26 anesthetized, mechanically ventilated patients with both LMA and PLMA. The laryngeal mask positioning was fiberoptically evaluated. Differences in the respiratory mechanics of the LMA and the PLMA were attributed to the differences between the laryngeal masks. RESULTS: In the total study population the airway resistance was 1.5 +/- 2.6 hPa.l-1.s-1 (P = 0.005) higher with the PLMA than with the LMA. During the PLMA use, the peak expiratory flow reduced by 0.02 +/- 0.05 l min-1 (P = 0.046), the expiratory resistance increased by 0.6 +/- 1.3 hPa.l-1.s-1 (P = 0.022), and the time constant of respiratory system lengthened by 0.09 +/- 0.18 s (P = 0.023). These differences doubled when the LMA was better positioned than the PLMA, whereas they disappeared when the PLMA was positioned better than the LMA. CONCLUSIONS: The standard LMA offers a lower resistive load than the PLMA. Moreover, the fitting between the laryngeal masks and the larynx, as fiberoptically evaluated, plays a major role in determining the resistive properties of these devices.

Adult↗
PubMed2003

Comparison of the standard laryngeal mask airway and the ProSeal laryngeal mask airway in obese patients.

BACKGROUND: The ProSeal laryngeal mask airway (PLMA) may have advantages over the laryngeal mask airway (LMA) in obese patients. We tested this hypothesis in a clinical setting. METHODS: Sixty obese patients (BMI >30) were randomized to receive mechanical ventilation (tidal volume 7 ml kg(-1), PEEP 10 cm H(2)O), through either the PLMA or the LMA. A gastric tube was used in all patients. Cuff pressure was set at 60 cm H(2)O and increased progressively until excessive leak occurred. The incidence of sore throat was assessed at recovery and after 1 week. RESULTS: The mean leak fraction was 6.1 (SD 2.9)% with the LMA and 6.4 (3.5)% with the PLMA (P=0.721). With the PLMA, with no sign of ventilation problems, the drainage tube was not patent in three patients. The cuff pressure was >100 cm H(2)O in 38% of the LMA group and 7% of the PLMA group (P=0.05). The incidence of sore throat was similar in both groups and it was similarly scored in the recovery room and 1 week after surgery. CONCLUSIONS: Both the PLMA and the LMA can be used for mechanical ventilation of obese patients. The patency of the PLMA drainage tube needs to be checked constantly even when an optimal airtight seal is present. In obese patients the LMA requires a greater cuff pressure than the PLMA, but sore throat is not related to the cuff pressure. Sore throat assessment in the recovery room appears as reliable as assessment later.

Adult↗
PubMed2002

Impact of laryngeal mask airway and tracheal tube on pulmonary function during the early postoperative period.

BACKGROUND: The tracheal tube (TT) produces reversible bronchoconstriction and increases pulmonary airway resistance compared to the laryngeal mask airway (LMA). The possible persistence of this effect in the postoperative period has not been studied. The aim of this study was to compare the early postoperative pulmonary function in healthy patients undergoing minor surgical procedures with the LMA or with the TT. METHODS: Sixty patients scheduled for saphenous vein stripping under general anaesthesia were randomised to receive the LMA or the TT. Before anaesthesia and 20 min after LMA or TT removal, pulse oxymetry values (SpO(2)) were recorded and patients performed forced spirometry in the supine position. RESULTS: Preoperative pulmonary function was normal in both groups. There were no differences between groups in the preoperative respiratory function test and SpO(2). Following surgery SpO(2), forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and peak expiratory flow (PEF) decreased in both groups. The FEV1/FVC did not change in either of the groups. In the TT group, compared to patients using the LMA, there was a greater relative decrease of SpO(2) (2.7 +/- 2.7% vs. 1.3 +/- 2.2%, P=0.017), FEV1 (17.6 +/- 12.2% vs. 8 +/- 17.4%, P=0.008), FVC (15.8 +/- 12.4% vs. 9 +/- 13.4%, P=0.023) and PEF (20.6% +/- 15.3% vs. 8.1 +/- 33.3%, P=0.033). CONCLUSIONS: This study demonstrates greater early postoperative respiratory restrictive syndrome and lower arterial oxygen saturation following tracheal intubation compared to LMA use in patients without respiratory disease.

Blood Gas Analysis↗
PubMed2002

[Computerized modification of Fukuda test].

OBJECTIVES: To study a new method to apply to Fukuda test in order to overcome the interpretational difficulty associated with a subjective evaluation of the exam. MATERIALS AND METHODS: During the exam, the patient wears a specially-designed headpiece, with a band at the back fitted with a sensor accommodating both a gyroscope and a bi-axial accelerometer. When asked to step in place, he does so in the Romberg position, eyes closed, successively rotating his head to the right and to the left. RESULTS: On analyzing the data obtained through the laterality variable (right/left oscillation) and time variable, it resulted that the difference between the averages referring to the laterality variable of right-handed and left-handed subjects was statistically significant (P = 0.001), while the difference between the averages of the time variable was not. CONCLUSIONS: To be able to propose an evaluation of the clinical validity of the test, further research must be carried out on pathological subjects, thus verifying the applicability of the method to the full.

Adolescent↗
PubMed2001

Pressure controlled versus volume controlled ventilation with laryngeal mask airway.

STUDY OBJECTIVE: To quantify the impact on peak airway pressure of pressure-controlled and volume-controlled ventilation during Laryngeal Mask Airway (LMA) use. DESIGN: Prospective, crossover clinical study. SETTING: University-affiliated hospital. PATIENTS: 32 ASA physical status I and II patients undergoing general anesthesia with the LMA. INTERVENTIONS: Patients were ventilated for three minutes both with pressure-controlled and volume-controlled ventilation, provided that tidal volume (V(T) ) and inspiratory time (It) were constant. MEASUREMENTS AND MAIN RESULTS: The monitored parameters were electrocardiography, arterial blood pressure, pulse oximetry, capnography, neuromuscular transmission, airway pressure and flow, and concentration of ventilated vapors and gases. The actually delivered V(T) was similar with both types of ventilation (volume-controlled = 0.67 +/- 0.13 lt, pressure-controlled = 0.67 +/- 0.14 lt; p = 0.688). Peak airway pressure was lower during pressure-controlled ventilation (14.6 +/- 3.5 cmH(2)O) than during volume-controlled ventilation (16 +/- 4 cmH(2)O) (p < 0.001). Furthermore, we noted that the higher the airway pressure with volume-controlled ventilation, the greater was the reduction in airway pressure during pressure-controlled ventilation. CONCLUSIONS: Pressure-controlled rather than volume-controlled ventilation can improve the effectiveness of mechanical ventilation in patients with high airway pressure.

Adult↗
PubMed1995

[Metabolic tolerance of isradipine. Evaluation after three months of therapy].

The aim of the present study was to evaluate efficacy on blood pressure values and metabolic tolerability of Isradipine, which was given to 15 mild hypertensive non diabetic subjects (average age 63.8 +/- 10.9 years), at the dosage of 5 mg once a day. Plasma lipids concentrations and oral glucose tolerance test (OGGT) with plasma insulin assay were carrid out before, after one and three months of therapy. The statistical analysis was done using the Student's t test for paired data. Isradipine showed a good efficacy on lowering high blood pressure. In no patients the drug induced impaired glucose tolerance. Isradipine had contrasting, but not statistically significant effects on lipid concentrations, namely, decrease of triglycerides, increased of any form of cholesterol (total, HDL, LDL), apoproteins and lipoprotein(a).

Aged↗
PubMed1986

Vitamin E deficiency alters the in vivo Rb+ discrimination of rat brain cortical cells.

The in vivo Rb+ uptake and release of rat brain cortical cells of 11-months-old rats fed with a vitamin E deficient diet was investigated. The animals were treated with a daily dose of 30 mg RbCl/100 g body weight for 14 days. After discontinuation of the RbCl treatment the animals were killed at intervals of 2, 4, 9 and 15 days, respectively. The intracellular Rb+ and K+ contents were analyzed by energy dispersive X-ray microanalysis, whereas concentrations of these two ions were determined by atomic absorbtion spectrophotometry in the serum and cerebrospinal fluid. Vitamin E deficient rats accumulate more Rb+ than age-matched normally fed animals at any time taken into account. Rb+-discrimination ratios calculated on the basis of Rb+ and K+ contents of both, cortical cell cytoplasm and cerebrospinal fluid, are higher in vitamin E deficient rats than in the controls (+20%), which supports the view that the enhanced membrane lipid peroxidation induced by vitamin E deficiency impairs the passive membrane permeability for Rb+ (and K+).

Aging↗
PubMed1984

Complement and its fractions (C3-C4) pattern in subjects with neoplasia.

The total complement (CH50) and its fractions C3 and C4 have been assayed for up to two years after surgery in subjects with breast, gastric and colon-rectum carcinomas. In all three types of pathology a constant pattern has been observed. Before surgery the CH50 stayed below the normal range but was increased following surgery. After a month it was again within the normal range and subsequently, according to the clinical evolution of the disease, it remained normal in those patients without relapse or any apparent metastasis, whereas in those patients who displayed metastasis and/or approached the terminal phase it fell below the normal range. The C3 fraction followed the CH50 pattern whereas the C4 did not show any variation correlated with the stages of the disease.

Breast Neoplasms↗
PubMed1982

In vitro lymphocyte sensitivity test to methisoprinol in different pathological conditions.

The present paper describes an in vitro study with Methisoprinol, carried out by means of various lymphocyte sensitivity tests in different pathological conditions. Methisoprinol does not exert any effect--neither on responsiveness nor on lymphocyte function--in healthy subjects, while in subjects with immunodepressive pathology the drug is capable of increasing these parameters either alone (rosettes) or in conjunction with mitogens (rosetting) at doses between 50 and 100 micrograms/ml.

Brain Neoplasms↗
PubMed1982

Effect of immunization against human chorionic gonadotropin (hCG) on transplantation of Yoshida ascitic tumour.

The human chorionic gonadotropin (hCG) is considered a marker of DNA derepression on neoplastic cells. The human chorionic gonadotropin antibodies (anti-hCG antibody) inhibit the growth of yoshida tumour cells in preimmunized recipient rats. A close relationship between the anti-hCG antibodies and tumour cell transplantation has been observed. This relationship and further experimental implications are briefly discussed.

Animals↗