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Biomedical subjects

M Borelli

Publications and source records attributed to M Borelli.

At least 19 recordsLinked to original sources
PubMed2000

Hemodynamic and gas exchange response to inhaled nitric oxide and prone positioning in acute respiratory distress syndrome patients.

OBJECTIVE: To analyze the single effect and the interaction of prone position and inhaled nitric oxide (iNO) on lung function and hemodynamic variables. DESIGN: 2 x 2 factorial trial. SETTING: Department of intensive care medicine at a university hospital. PATIENTS: Fourteen patients on volume-controlled mechanical ventilation for acute respiratory distress syndrome (ARDS). INTERVENTION: Four experimental conditions, each one characterized by the patient's position (supine or prone) with iNO or without iNO. MEASUREMENTS AND RESULTS: Hemodynamic and gas exchange data were collected for each experimental condition. PaO2 was increased both by positioning (p < .01) and iNO (p < .01); iNO caused also a reduction in venous admixture (p < .01), pulmonary artery pressure (p < .01), and pulmonary vascular resistance index (p < .05). We could not demonstrate any significant interaction between the two treatments. The average effect of prone positioning was the same both with and without iNO, whereas the average effect of iNO was the same in both the prone and the supine position. CONCLUSION: In the studied acute respiratory distress syndrome patients the average effects of iNO and positioning on oxygenation were additive and no interaction could be shown. A strategy including both treatments could warrant the best improvement in oxygenation, and should take into account the individual response to each treatment and the possible combination of the two.

Administration, Inhalation↗
PubMed1998

Effects of continuous negative extrathoracic pressure versus positive end-expiratory pressure in acute lung injury patients.

OBJECTIVE: To compare the effects of continuous negative extrathoracic pressure (CNEP) and positive end-expiratory pressure (PEEP) at the same level of transpulmonary pressure. DESIGN: Prospective analysis. SETTING: Medical intensive care unit of a university hospital. PATIENTS: Nine consecutive acute lung injury patients. Patients with cardiac failure and patients with chronic lung disease were excluded from the investigation. INTERVENTIONS: The patients were sedated and paralyzed while receiving mechanical ventilation and were studied in three different conditions: a) using a PEEP of 0 cm H2O (zero end-expiratory pressure); b) using a PEEP of 15 cm H2O; c) using CNEP. CNEP was applied to the thorax and the upper abdomen and its level was chosen to obtain a transpulmonary pressure similar to the one observed at a PEEP of 15 cm H2O. All patients had an arterial catheter, a pulmonary artery catheter, and a thermistor-tip fiberoptic catheter for thermo-dye-dilution in the femoral artery. These catheters were connected to an integrated monitoring system. We also placed an esophageal catheter in each patient to detect esophageal pressure. MEASUREMENTS AND MAIN RESULTS: For each step, we assessed the hemodynamic variations by measuring intravascular pressures (via a pulmonary artery catheter), transmural pressures (computed by subtracting esophageal pressure from intravascular pressure), and blood volumes (derived from the technique of double indicator). The application of CNEP of -20+/-0.7 cm H2O produced a venous admixture and PaO2/FO2 improvement similar to that obtained with a PEEP of 15 cm H2O. This procedure is associated with a higher cardiac index (5.5+/-1.5 vs. 4.6+/-1.2 L/min/m2; p < .05) coupled with lower central venous pressure, pulmonary artery occlusion pressure, and higher transmural pressures and blood volume parameters. CONCLUSIONS: In acute lung injury patients, a CNEP of -20 cm H2O has the capability to obtain transpulmonary pressure and lung function improvement similar to a PEEP of 15 cm H2O. CNEP differs from the positive pressure by increasing the venous return and the preload of the heart, and has no negative effects on cardiac performance.

APACHE↗
PubMed1996

Relief of hypoxemia contributes to a reduction in cardiac index related to the use of positive end-expiratory pressure.

OBJECTIVE: We have investigated the role that improvement in arterial oxygenation has, consequent on positive end-expiratory pressure (PEEP), in the reduction of cardiac index (CI) determined by applying PEEP. DESIGN: 2 x 2 factorial trial. SETTING: Department of intensive care medicine at a university hospital. PATIENTS: 13 patients on mechanical ventilation for acute lung injury. INTERVENTIONS: Four experimental conditions, each one characterized by one level of PEEP and one level of PaO2: LOLP = Low PaO2 (approximately 50 mmHg) Low PEEP (approximately 1 cmH2O) LOHP = Low PaO2 (approximately 50 mm Hg) High PEEP (approximately 10 cmH2O) HOLP = High PaO2 (approximately 80 mmHg) Low PEEP (approximately 1 cmH2O) HOHP = High PaO2 (approximately 80 mmHg) High PEEP (approximately 10 cmH2O) MEASUREMENTS AND RESULTS: Hemodynamic and gas exchange data were collected for each experimental condition. CI showed a 13% decline from LOLP (7.0 +/- 1.71/min per m2) to HOHP (6.1 +/- 1.31/min per m2). Both the direct effect of PEEP on the CI (LOLP + HOLP vs LOHP + HOHP, p < 0.01) and the indirect effect related to the improvement in oxygenation (LOLP + LOHP vs HOLP + HOHP, p < 0.01) contributed to the reduction in CI. CONCLUSIONS: In evaluating CI changes induced by PEEP we should take into account the indirect effect of arterial oxygenation upon CI. This should be considered, at least in part, as a physiological adjustment rather than as impaired cardiovascular performance.

Adult↗
PubMed1990

Long-term cardiopulmonary bypass by peripheral cannulation in a model of total heart failure. The decompression of the left heart through a percutaneous helical spring positioned within the lumen of the tricuspid and pulmonary artery valves.

We performed long-term closed-chest cardiopulmonary bypass in an animal model of total heart failure (induced ventricular fibrillation). The extracorporeal system included a venous reservoir, a roller pump, a membrane lung, and a blood pulsator system. We cannulated the right external jugular vein for venous drainage and the right subclavian artery for arterial return. To decompress the left heart we passed by percutaneous cannulation a special helical spring mounted on a Swan-Ganz catheter (Baxter Edwards Divisions, Irvine, Calif.) and positioned it to rest within the pulmonary artery and tricuspid valves, which rendered them partly incompetent. After induced ventricular fibrillation, blood flow was raised to keep the central venous pressure at baseline values. The lungs were ventilated with 5% carbon dioxide in room air. During bypass, mean pulmonary artery pressure was 10.0 +/- 1.7 mm Hg, mean wedge pressure 11.9 +/- 1.8 mm Hg, and mean blood pressure 95.2 +/- 5.6 mm Hg. After 2 days (four animals) and 3 days (two animals) the hearts were defibrillated. There was immediate ejection from both sides of the heart. All sheep were weaned from bypass within 29 +/- 11 minutes and their lungs were ventilated with room air within 42 +/- 34 minutes. At autopsy hearts and lungs grossly appeared normal. We conclude that the percutaneous helical spring resting within right heart valves provided excellent decompression throughout the study, with full recovery of heart and lung function on defibrillation.

Animals↗
PubMed1988

Severe acute respiratory failure managed with continuous positive airway pressure and partial extracorporeal carbon dioxide removal by an artificial membrane lung. A controlled, randomized animal study.

Using an animal model of acute respiratory failure (ARF), we evaluated two treatments: conventional mechanical pulmonary ventilation (MV) and continuous positive airway pressure (CPAP) with extracorporeal removal of CO2 by an artificial membrane lung. We developed a model of "mild" ARF and a model of "severe" ARF after ventilating healthy sheep at a peak inspiratory pressure of 50 cm H2O for various lengths of time. Sheep from either injury models were randomly assigned to one of the above treatment groups. All 16 sheep from the model with "severe" ARF died, with progressive deterioration in pulmonary function and multiorgan failure irrespective of the treatment. Of 11 sheep from the model with "mild" ARF treated by MV, only three survived, whereas all 11 sheep from the model with "mild" ARF treated with CPAP and extracorporeal removal of CO2 responded well, and nine sheep ultimately recovered. We conclude that CPAP with extracorporeal removal of CO2 provided a better environment for the recovery in our model with "mild" ARF than the conventional arrangement centered on MV alone. Our studies also suggest that lung injury can progress (i.e., model with "severe" ARF) to where neither of the two treatments can succeed.

Acute Disease↗
PubMed1987

ECMO revisited.

Explore the source record for details and available documents.

Humans↗
PubMed1985

Mean airway pressure vs. positive end-expiratory pressure during mechanical ventilation.

To investigate the effects of both positive end-expiratory pressure (PEEP) and mean airway pressure (Paw) on gas exchange, we used lung lavage to induce severe respiratory insufficiency in six lambs. The animals were then mechanically ventilated at constant tidal volume, respiratory rate, and inspired O2 fraction. PEEP levels were varied -5, +5 and +10 cm H2O around the pressure (Pflex) corresponding to a major change in slope of the inspiratory limb of the respiratory volume-pressure curve. In each animal the effects of the three PEEP levels were studied at two Paw levels, differing by 5 cm H2O. Increasing Paw significantly improved PaO2 and reduced venous admixture. A 5-cm H2O PEEP increase from +5 to +10 did not affect oxygenation; however, oxygenation was significantly better when PEEP was greater than Pflex. Both PaCO2 and anatomic dead space were higher at higher PEEP, and decreased with increasing Paw. Hence, Paw was a major determinant of oxygenation, although a PEEP greater than Pflex appeared necessary to optimize oxygenation at a constant Paw.

Analysis of Variance↗
PubMed1978

Pelvic neurilemmoma.

A rare case of benign pelvic neurilemmoma with bladder infiltration and ureteral obstruction is presented. This neurally originated tumor may occur anywhere in the body, but involvement of the urinary tract is rare. Management depends upon location and other clinical findings, and in this case, since complete removal was impossible, urinary derivation was employed as a palliative treatment.

Female↗
PubMedDate not supplied

Long-term closed chest partial and total cardiopulmonary bypass by peripheral cannulation for severe right and/or left ventricular failure, including ventricular fibrillation. The use of a percutaneous spring in the pulmonary artery position to decompress the left heart.

The authors report that total cardiopulmonary bypass (CPBP) for severe heart failure can be safely maintained for several days through peripheral cannulation alone. In two healthy sheep under general anesthesia, the authors cannulated the right external jugular vein and the right subclavian artery. A special spring was attached to a 7F Swan-Ganz catheter and positioned at the level of the pulmonary artery (PA) valve, rendering it partially incompetent. The extracorporeal circuit included a venous reservoir, a roller pump, a membrane lung, and a blood pulsator set at 25 beats/min. Ventricular fibrillation was induced with 110 VAC. Extracorporeal blood flow was raised to 100-120 ml/kg min. Mechanical pulmonary ventilation was changed to 5% CO2 in room air. During bypass, the wedge pressure (WP) averaged 9-13 mmHg, PA pressure 7-13 mmHg, and central venous pressure 1-9 mmHg. After 38 and 48 hr respectively the hearts were defibrillated with DC shock. There was total heart failure with no ejection from right or left. We continued with TCPBP. The right heart recovered after 1 and 3 hr respectively. After 7 and 5 hr, respectively, there was some aortic ejection. By 11 and 4 hr, respectively, the sheep were off bypass and on room air, with return to baseline cardiac function. Throughout the recovery the WP averaged 4-8 mmHg. At autopsy, all hearts were soft and normal in appearance. Histologic examination of the lungs and the heart was unremarkable. The authors conclude that the PA spring readily decompressed the LV. Ventilating lungs with 5% CO2 in air during CPBP sustained excellent lung function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗