['Mechanical ventilation of intensive care patients results in inspiratory muscle weakness. Inspiratory muscle training may be useful, but no studies have specifically described the physiological response to training.', 'Is inspiratory muscle training with a threshold device safe in selected ventilator-dependent patients? Does inspiratory muscle strength increase with high-intensity inspiratory muscle training in ventilator-dependent patients?', 'Prospective cohort study of 10 medically stable ventilator-dependent adult patients.', 'Tertiary adult intensive care unit.', 'Inspiratory muscle training 5-6 days per week with a threshold device attached to the tracheostomy without supplemental oxygen.', 'Physiological response to training (heart rate, mean arterial pressure, oxygen saturation and respiratory rate), adverse events, training pressures.', "No adverse events were recorded in 195 sessions studied. For each patient's second training session, no significant changes in heart rate (Mean Difference 1.3 bpm, 95% CI -2.7 to 5.3), mean arterial pressure (Mean Difference -0.9 mmHg, 95% CI -6.4 to 4.6), respiratory rate (Mean Difference 1.2 bpm, 95% CI -1.1 to 3.5 bpm) or oxygen saturation (Mean Difference 1.2%, 95% CI -0.6 to 3.0) were detected Training pressures increased significantly (Mean Difference 18.6 cmH(2)O, 95% CI 11.8-25.3)."] Is specific inspiratory muscle training safe in selected patients who are ventilator-dependent : a case series?