الفهرس Only 14 pages are availabe for public view
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Abstract
Background: Mechanical ventilation induces changes in lung volumes and intrathoracic pressures which are transmitted to the heart, great arteries and veins and therefore independently affect the key determinants of cardiovascular performance and consequently heart rate and myocardial contractility. New ventilatory modes as proportional assist ventilation with more patient synchrony may have better hemodynamic effects. Aim of the study: To evaluate the changes in hemodynamics, left ventricular and right ventricular function during different modes of mechanical ventilation. Patients and methods: 100 patients who received mechanical ventilation, when they they fulfilled all the criteria for a spontaneous breathing trial (improvement of the underlying cause of acute respiratory failure, body temperature <39{u00B0}C, hemoglobin level >7G/dl, PaO2>60 mmHg, FIO2<40%, positive end expiratory pressure (PEEP) under or equal to 8 cm H2O, respiratory rate less than 35 breathes/minute, systolic arterial pressure >90 mmHg and <160 mmHg without need for vasoactive drugs, no sedation and a stable neurological status) were recruited in the study. Thoracic electrical bioempedance and transthoracic echocardiography were used to assess hemodynamics, LV and RV functions at 4 phases which are PC-ACV just before starting SBT, 2 hours after SBT trial with PS 10, PEEP 5, 3rd phase after 2 hours on PAV mode with 20-30% assist, finally during spontaneous breathing after disconnection of mechanical ventilation. Results: There was no significant changes in systolic and diastolic blood pressure between the 4 phases. HR and RR were statistically significantly higher during spontaneous breathing