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Biomedical subjects

A Pesenti

Publications and source records attributed to A Pesenti.

At least 109 records · Page 6Linked to original sources
PubMed1983

Venous admixture (Qva/Q) and true shunt (Qs/Qt) in ARF patients: effects of PEEP at constant FIO2.

Venous admixture (Qva/Q) in ARF patients is due to both true right to left shunt (Qs/Qt: perfusion of truly unventilated areas) and to maldistribution [Qva-Qs)/Qt: effects of unevenness of ventilation/perfusion ratio). Using the retention rate of sulphur hexafluoride we determined the effects of PEEP on Qs/Qt and (Qva-Qs)/Qt at a constant FIO2 for each patient (0.57 +/- 0.19 SD, range 0.4-0.95). Eleven patients with ARF (treated either by CPPV or CPAP) were studied on 16 occasions. Each measurement was repeated at two levels of PEEP, 5 cm H2O below and 5 cm H2O above the patient's clinically determined PEEP level. The increase in PEEP resulted in: - a decrease in Qva/Q (from 0.37 +/- 0.13 to 0.27 +/- 0.12, p less than 0.01); - a parallel decrease in Qs/Qt (from 0.29 +/- 0.16 to 0.22 +/- 0.14, p less than 0.01); there was a positive correlation between Qva/Q and Qs/Qt changes (r = 0.53, p less than 0.05). No significant variation was demonstrated in (Qva-Qs)/Qt (from 0.074 +/- 0.045 to 0.054 +/- 0.048). On the other hand there was a negative correlation between the fraction of Qva/Q due to the maldistribution and FIO2: (Qva-Qs)/Qva = 0.75-0.86 FIO2 (r = 0.74, p less than 0.01). We conclude that: PEEP decreased Qva/Q mainly through changes in Qs/Qt but did not have a definite effect on (Qva-Qs)/Qt. Maldistribution was responsible for a significant portion of Qva/Q in those ARF patients tolerating a relatively low FIO2 (0.4-0.6).

Acute Disease↗
PubMed1983

Management of the antenatal preterm fetal lung in the prevention of respiratory distress syndrome in lambs.

We have explored change in pulmonary compliance before, and after, repeated deep insufflation of the lungs to a pressure of 35 cm H2O, in 130-days gestation fetal lambs delivered by cesarean section, and while still connected to the intact umbilical cord and the ewe. As a group, all 15 out of 28 fetal lambs that had a rise in total compliance to above 0.2 ml (cm H2O)-1 kg-1 after the first inflation, tolerated 24 h of mechanical ventilation with excellent health and good lung function; only 3 animals out of 13 that showed no similar initial rise in compliance after the first inflation, ultimately survived. We believe the first deep insufflation is an important therapeutic intervention and a useful index to rapidly assess chance of survival in a high-risk fetal lamb population.

Animals↗
PubMed1982

Prevention of hyaline membrane disease in premature lambs by apneic oxygenation and extracorporeal carbon dioxide removal.

Hyaline membrane disease is found only in lungs where pulmonary ventilation has been established, i.e. after birth. We delivered eleven fetal lambs of a gestational age of 128-130 days but instead kept their lungs in total apnea and inflated to constant pressure, while removing all metabolically produced carbon dioxide with an extracorporeal membrane lung. Oxygen was provided by the membrane lung, and by apneic oxygenation through the natural lungs. Hence, arterial blood gases remained always normal, without any pulmonary ventilation. After 6-66 h the lungs had sufficiently cleared to allow normal mechanical pulmonary ventilation in 10 our of 11 lambs so treated. In a control group treated with mechanical ventilation alone, five of seven lambs died within the first 24 h of severe hyaline membrane disease.

Animals↗
PubMed1982

Simple estimate of the true right to left shunt (Qs/Qt) at maintenance F1O2 by sulphur hexafluoride retention.

Differentiating Qs/Qt over Qva/Q (as measured by the standard O2 content formula) appears to be of great interest in applying and evaluating different therapeutic approaches. The estimation of Qs/Qt by 100% O2 breathing may alter "per se" the lung condition and is unsatisfactory. We used Sulphur Hexafluoride (SF6; lambda = 6.10(-3) ml ml-1 760 mmHg-1) to identify the true shunt (VA/Q less than 0.05) at maintenance F1O2. A simple and rapid determination of SF6 retention is performed by ECD gas chromatography from contemporaneous arterial and mixed venous blood samples, taken during i.v. infusion of an SF6 containing solution. QS/Qt estimate is then given by the ratio: PaSF6/PvSF6. It is not necessary to know the absolute gas partial pressures or concentration, hence absolute gas calibrations are not required. This method is suggested as feasible and satisfactory for clinical use, allowing the determination of QS/Qt at the maintenance F1O2.

Fluorides↗
PubMed1981

Effect of PGI2 infusion during long term extracorporeal circulation with membrane lung in sheep.

PGI2 plus very low dose of heparin was infused in 6 lambs connected for long term extracorporeal circulation with a membrane lung. Hemodynamic and hemostasis parameters were compared to those of a control group treated only with standard doses of heparin. PGI2 efficacy in inhibiting platelet aggregation and platelet fall was confirmed. A small platelet release, measured as antiheparin activity, was observed during all the by-pass, but did not influence platelet capacity of recovering when PGI2 effect dissolved. Heparin needed resulted less than a quarter of the quantity used for the control group. In our experimental conditions the hemodynamic changes were mainly limited to a decrease in diastolic blood pressure.

Animals↗
PubMed1981

[Wilkie's syndrome: etiopathogenetic, clinical and therapeutic aspects of some cases we have seen].

The Authors hold that for the onset of the clinical manifestations of the Wilchie's syndrome the contemporary appearance of 2 causes is necessary: the first is an anatomical variance of the organs comprising that particular anatomical location and the second being a pathological alteration taking place in one or more of these set organs. Moreover they suggest appropriate surgical procedure art at removing both causes that produced the disease.

Duodenal Obstruction↗
PubMed1980

Treatment of acute respiratory failure with low-frequency positive-pressure ventilation and extracorporeal removal of CO2.

Terminal respiratory failure was reversed in three patients with a combination of extra-corporeal CO2 removal through a membrane lung and oxygen diffusion into the diseased lungs between mechanical breaths induced at a frequency of 2-3/min. The technique seems to prevent the pulmonary barotrauma and extrapulmonary derangements caused by conventional mechanical ventilation.

Acute Disease↗