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Biomedical subjects

L Gattinoni

Publications and source records attributed to L Gattinoni.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1980

Hemodynamics and renal function during low frequency positive pressure ventilation with extracorporeal CO2 removal. A comparison with continuous positive pressure ventilation.

Six lambs were anesthetized and connected venovenous mode to a Membrane Lung for Extracorporeal CO2 removal. The animals underwent several hours periods of continuous positive pressure ventilation (CPPV), at 5 cmH2O positive end expiratory pressure (PEEP), alternated with several hours periods of low frequency positive pressure ventilation (5 cmH2O PEEP, 2 b.p.m.) with extracorporeal CO2 removal (LFPPV-ECCO2R). During LFPPV-ECCO2R compared with CPPV, cardiac output increased by 26%, pulmonary vascular resistances and systemic vascular resistances decreased by 28% and 22% respectively. The renal function improved significantly during LFPPV-ECCO2R compared with CPPV, i.e. urinary flow, creatinine clearance and osmolar clearance increased by 50%, 37% and 52% respectively. In these experiments LFPPV-ECCO2R, a form of completely artificial ventilation, seems to prevent hemodynamic and renal complications of CPPV.

Animals↗
PubMed1979

Acid-base equilibrium in the blood of sheep.

The acid-base equilibrium in the blood of sheep is different from that of human blood mainly because of a lower concentration of 2,3-DPG. A nomogram relating pH, pCO2, total CO2 content and base excess has been developed.

Acid-Base Equilibrium↗
PubMed1979

Hemodynamic, mechanical and renal effects during "apneic oxygenation" with extracorporeal carbon dioxide removal, at different levels of intrapulmonary pressure in lambs.

It has been shown that apneic oxygenation can be safely performed for many days when metabolic carbon dioxide is removed by an extracorporeal membrane lung, and 100% oxygen is supplied directly into the trachea to keep the intrapulmonary pressure at 5 cm. H2O. The study was designed to find "best intrapulmonary pressure (IP)", analogous to "best PEEP" during continuous positive pressure ventilation. In the present study we have shown that when IP was progressively raised from 5cm H2O to 20 cm H2O the PaO2 rose significantly due to progressive decrease in QVA/Q. A linear positive correlation was found between CO and QVA/Q. There was a negative correlation between QVA/Q and FRC. Total static lung compliance and FRC increased significantly at 15--20 cm H2O IP. There was no significant change in urinary flow, urea and creatinine clearances. We conclude that in apneic oxygenation a more "optimal IP" is attained at an IP pressure of 20 cm H2O than at 5 cm H2O.

Animals↗
PubMed1978

Oxygen affinity in the blood of sheep.

The oxygen affinity in the blood of adult Dorset sheep with HbB was studied by determining several oxygen equilibrium curves under different conditions of pH and PCO2 by a method that allowed strict control of pH, PCO2, and HCO3- concentration over the entire curve. Nomograms and equations were derived that allowed the estimation of the oxygen saturation in a sample of blood in the range 0 to 100%, either from pH, PCO2 and PO2, or from PO2 and known P50. The advantage of this approach is that no assumptions about the shape of the oxygen equilibrium curve need be made (i.e. the Hill parameter, n, is not required to be constant), since the entire curve was measured.

Animals↗
PubMed1978

Control of intermittent positive pressure breathing (IPPB) by extracorporeal removal of carbon dioxide.

Five lambs were anaesthetized, paralysed, mechanically ventilated and connected to a membrane "lung" to permit removal of carbon dioxide. When part of the carbon dioxide was removed in this manner, the tidal volume was decreased to keep PaCO2 constant. For example, when 70% of carbon dioxide was removed by the membrane lung, total ventilation was reduced by 50%, peak inspiratory pressure was decreased by 45%, and PaO2 was kept constant by increasing the inspired oxygen fraction from 0.21 to 0.27%. The removal of carbon dioxide by a membrane during positive pressure breathing could decrease barotrauma, particularly in poorly compliant lungs. Technically, the extracorporeal removal of carbon dioxide is relatively simple procedure.

Animals↗
PubMed1978

An alternative to breathing.

If carbon dioxide is removed by an extracorporeal membrane lung ventilated with room air, the natural lung can be used for oxygen transport alone; we have demonstrated this in lambs by maintaining lungs "inflated" with 100 percent oxygen at constant pressure and removing all carbon dioxide through the membrane lung. This process is a variant of "apneic oxygenation" without its disadvantages, because the arterial pH, PCO2, and PO2 all remain normal. No nitrogen washout is needed. These studies were carried out in five lambs anesthetized and paralyzed for 24 hours. For carbon dioxide removal, blood from the subclavin artery was pumped through an extracorporeal membrane lung and was returned into the external jugular vein. For oxygen delivery, the lungs were inflated through a tracheostomy tube with 100 percent oxygen to a pressure of 5 cm. H2O. There was no significant change in arterial blood PO2 after perfusion had begun or at the end of the perfusion 24 hours later. The arterial PCO2 remained steady, and there was no change in acid-base balance. The functional residual capacity (FRC) and static lung compliance remained unchanged. The total dead space was 10 to 15 ml. All animals recovered and survived in good health. At equilibrium, alveolar nitrogen partial pressure was always equal to the partial pressure of nitrogen in the ventilating gas of the membrane lung and was the sole determining factor in controlling alveolar oxygen concentration. Direct measurement of pulmonary gas showed alveolar gas at the level of the carina.

Animals↗
PubMed1977

Control of breathing using an extracorporeal membrane lung.

Various amounts of carbon dioxide were removed through an extracorporeal membrane lung in spontaneously breathing lambs. The decrease in alveolar ventilation was proportional to the fraction of total carbon dioxide removed by the membrane lung. When extracorporeal CO2 removal approximated CO2 production (VCO2), alveolar ventilation almost ceased. Pulmonary ventilation can be controlled by extracorporeal carbon dioxide removal.

Animals↗
PubMed1976

[The significance of hemogasanalysis in acute myocardial infarction: hemodynamic and respiratory correlations (author's transl)].

Hemodynamic and hemogasanalytic comparative study was performed in 46 patients admitted to our Coronary Care Unit because of myocardial infarction. The values of pH; PO2; PCO2; HbaO2; HbvO2; SBP; CVP; PAP; WP; Q; and CI were recorded simultaneously in every patient one or more times during the first 72 hours of the disease. The patients were divided into four classes according to the severity of hemodynamic impairment. Statistical analysis of the obtained results was then performed. In all patients more or less severe hypoxemia was found, but it was not statistically related to the severity of hemodynamic impairment. Instead, the values of PvO2 and HbvO2 showed a very significant correlation with Q and CI. Moreover, in 11 patients the venous admixture (QVA/Q) was measured several times in order to study the cause of the arterial hypoxemia thoroughly. It showed a very significant direct correlation with Q and CI. The interpretation of this phenomenon is then discussed and it is suggested that, in such patients, an increase of cardiac output causes an increased flow through poorly ventilated areas.

Aged↗
PubMed1975

Hemoglobin oxygen affinty in patients with low-output heart failure and cardiogenic shock after acute myocardial infaraction.

The aim of this study was to determine the oxigen affinity actually present in vivo in blood from patients with acute myocardial infarction. Patients with uncomplicated acute myocardial infarction had normal value of P50 in vivo (partial pressure of oxygen at which 50 percent of the hemoglobin is saturated with oxygen at fixed levels of pHand PC02 present in vivo). Also the values of P50 in vivo of blood from patients with low cardiac output with mild or severe heart failured did not differ from the normal mean. This was the consequence of an increase of 2, 3-diphosphoglycerate levels (which reduces the oxygen affinity of hemoglobin) and of the immediate effect of alkalosis (Bohr effect). By contrast, the values of P50 in vivo were significantly increased in patients with cardiogenic shock. This could be ascribed to the state of acute acidiosis present in these patients. In these conditions the changes in the values of P50 in vivo play an important role in the oxygen delivery to the tissues. However, high values of P50 do not enhance oxygen delivery when a severe arterial hypoxemia (P02 smaller than 40-45 mm Hg) is also present.

Acid-Base Equilibrium↗