Antonio Pesenti

Esophageal and transpulmonary pressure in the clinical setting: meaning, usefulness and perspectives

PurposeEsophageal pressure (Pes) is a minimally invasive advanced respiratory monitoring method with the potential to guide management of ventilation support and enhance specific diagnoses in acute respiratory failure patients. To date, the use of Pes in the clinical setting is limited, and it is often seen as a research tool only.MethodsThis is a review of the relevant technical, physiological and clinical details that support the clinical utility of Pes.ResultsAfter appropriately positioning of the esophageal balloon, Pes monitoring allows titration of controlled and assisted mechanical ventilation to achieve personalized protective settings and the desired level of patient effort from the acute phase through to weaning. Moreover, Pes monitoring permits accurate measurement of transmural vascular pressure and intrinsic positive end-expiratory pressure and facilitates detection of patient–ventilator asynchrony, thereby supporting specific diagnoses and interventions. Finally, some Pes-derived measures may also be obtained by monitoring electrical activity of the diaphragm.ConclusionsPes monitoring provides unique bedside measures for a better understanding of the pathophysiology of acute respiratory failure patients. Including Pes monitoring in the intensivist’s clinical armamentarium may enhance treatment to improve clinical outcomes.

Percutaneous bridge to heart transplantation by venoarterial ECMO and transaortic left ventricular venting.

We report a case in which life support for cardiogenic shock was achieved by a nonpulsatile venoarterial bypass, and left ventricular decompression was obtained by a catheter placed percutaneously through the aortic valve into the left ventricle. The blood drained from the left ventricle was pumped into the femoral artery. The normalization of left heart filling pressures allowed the resolution of pulmonary edema, and the patient underwent a successful heart transplantation following 7 days of mechanical cardiocirculatory support.

Control of fever by continuous, low-dose diclofenac sodium infusion in acute cerebral damage patients

Objectives: The aim of this study was to assess the efficacy and safety of low doses of diclofenac sodium (DCF) in attaining normothermia with minimal major side effects in patients with acute cerebral damage. The study was designed to verify the adequate, prolonged antipyretic action of DCF infusion, to quantify its haemodynamic and cerebral impact and to assess any negative effect on renal and liver function. Design: Retrospective, cohort study on prospectively collected data. Setting: Intensive care unit (ICU) of a university hospital. Patient population: Five patients with subarachnoid haemorrhage and seven severe head-trauma victims with febrile illness of various infectious origin. Interventions: Continuous i. v. infusion of a low dose (0.04 mg/kg/h) of DCF for 48 h. Measurements and results: Systemic and cerebral haemodynamic data were collected at 4 h intervals for 8 h before diclofenac infusion and 48 h after. Renal and liver functions were monitored. Normothermia, defined as external temperature < 37.5 degrees Celsius (°C), was achieved in all cases. Intracranial pressure was significantly lowered and mean arterial pressure was unaffected, so cerebral perfusion pressure rose after DCF. Hepatic and renal function were not altered in the 48 h post DCF. Mean urinary output was preserved at high flow and was not influenced by DCF. Conclusions: Continuous infusion of low-dose DCF attained normothermia without any major cerebral or systemic side effects. Renal and liver functions were unaffected. Once normothermia was achieved, intracranial and cerebral perfusion pressure improved.

Extracorporeal gas exchange

Purpose of reviewWe report on recent advances and achievements on the use of extracorporeal gas exchange for long-term application in the therapy of critically ill patients with various forms of respiratory failure. Recent findingsThe most important results regarding the use of extracorporeal gas exchange are expected from the Conventional Ventilatory Support vs. Extracorporeal Membrane Oxygenation for Severe Adult Respiratory Failure (CESAR) study, a randomized clinical trial assessing the effectiveness of extracorporeal lung assist in acute respiratory distress syndrome patients. Although not yet formally published, the results of this study, if confirmed, represent the first positive randomized clinical trial on adult extracorporeal membrane oxygenation application in acute respiratory distress syndrome patients. Other important results come from the clinical application of interventional lung assist, a pumpless arteriovenous extracorporeal technique, in different clinical conditions (acute respiratory distress syndrome, bridge to transplantation, asthma, and trauma). Among technical progress, of particular interest is the development of microfiber, microporous polymethylpentene membrane lungs, which offer low resistance to blood flow, high gas transfer capability, and high leak-proof performance. SummaryResults of recent clinical trials, widespread use of clinical applications, and technical progress are leading to reevaluation and extension of extracorporeal gas exchange in critically ill patients with respiratory failure of various forms. Further developments may come from low invasive techniques with high efficiency of CO2 removal from low blood flow.

Control of Respiratory Drive and Effort in Extracorporeal Membrane Oxygenation Patients Recovering from Severe Acute Respiratory Distress Syndrome

Background:The amount of extracorporeal carbon dioxide removal may influence respiratory drive in acute respiratory distress syndrome (ARDS) patients undergoing extracorporeal membrane oxygenation (ECMO). The authors evaluated the effects of different levels of extracorporeal carbon dioxide removal in patients recovering from severe ARDS undergoing pressure support ventilation (PSV) and neurally adjusted ventilatory assist (NAVA). Methods:The authors conducted a prospective, randomized, crossover study on eight spontaneously breathing ARDS patients undergoing venovenous ECMO since 28 ± 20 days. To modulate carbon dioxide extraction, ECMO gas flow (GF) was decreased from baseline resting protective conditions (i.e., GF100%, set to obtain pressure generated in the first 100 ms of inspiration against an occluded airway less than 2 cm H2O, respiratory rate less than or equal to 25 bpm, tidal volume less than 6 ml/kg, and peak airway pressure less than 25 cm H2O) to GF50%-GF25%-GF0% during both PSV and NAVA (random order for ventilation mode). Continuous recordings of airway pressure and flow and esophageal pressure were obtained and analyzed during all study phases. Results:At higher levels of extracorporeal carbon dioxide extraction, pressure generated in the first 100 ms of inspiration against an occluded airway decreased from 2.8 ± 2.7 cm H2O (PSV, GF0%) and 3.0 ± 2.1 cm H2O (NAVA, GF0%) to 0.9 ± 0.5 cm H2O (PSV, GF100%) and 1.0 ± 0.8 cm H2O (NAVA, GF100%; P < 0.001) and patients’ inspiratory muscle pressure passed from 8.5 ± 6.3 and 6.5 ± 5.5 cm H2O to 4.5 ± 3.1 and 4.2 ± 3.7 cm H2O (P < 0.001). In time, decreased inspiratory drive and effort determined by higher carbon dioxide extraction led to reduction of tidal volume from 6.6 ± 0.9 and 7.5 ± 1.2 ml/kg to 4.9 ± 0.8 and 5.3 ± 1.3 ml/kg (P < 0.001) and of peak airway pressure from 21 ± 3 and 25 ± 4 cm H2O to 21 ± 3 and 21 ± 5 cm H2O (P < 0.001). Finally, transpulmonary pressure linearly decreased when the amount of carbon dioxide extracted by ECMO increased (R2 = 0.823, P < 0.001). Conclusions:In patients recovering from ARDS undergoing ECMO, the amount of carbon dioxide removed by the artificial lung may influence spontaneous breathing. The effects of carbon dioxide removal on spontaneous breathing during the earlier acute phases of ARDS remain to be elucidated.

A new approach to the prevention and treatment of acute pulmonary insufficiency.

Apneic oxygenation with extracorporeal removal of metabolically produced carbon dioxide, or its variants, is a powerful tool to markedly reduce spontaneous breathing, or mechanical pulmonary ventilation, and yet maintain normal arterial blood gases. We believe this environment of reduced pulmonary ventilation is the key to the prevention, and to the cure of acute pulmonary disorders in the neonate, and the adult. A recent report of a controlled study in the use of membrane lungs in adult respiratory distress syndrome (ARDS) has shown no difference between conventional pulmonary ventilator care, and when such a treatment was augmented by extracorporeal membrane lung (ML) blood gas exchange (Hill et al 1978): the latter group of patients lived a few days longer, but they too ultimately died. The treatment of ARDS at present carries a high risk of mortality. The variety of conditions that leads to ARDS shows no unique bacterial, viral, or toxic components. Indeed, aside from chest X-ray findings, severe ARDS is solely defined by highly abnormal blood gas values. Except for a diffuse involvement in ARDS, there is no suggestion that such a lesion alone, confined to one lung or one lobe of the lung, is not compatible with an uneventful hospital course, and hence routine survival. The question of optimal condition for the healing of the lungs is one that up to now has been synonymous with optimum blood gas values, obtainable irrespective The International Journal Of Artificial Organs I Vol. 3 no. 2, 1980 J p.p. 86-93 :r by Wichtig Editor. srt. 1980

Simple estimate of the true right to left shunt (Qs/Qt) at maintenance F1O2 by Sulphur Hexafluoride retention

AbstractDifferentiating 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; λ=6.10−3 ml ml−1 760 mmHg−1) to identify the true shunt (VA/Q<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/P

Angiotensin-(1-7) improves oxygenation, while reducing cellular infiltrate and fibrosis in experimental Acute Respiratory Distress Syndrome

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