European journal of anaesthesiology
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Biphasic Positive Airway Pressure (BIPAP) can be described as pressure controlled ventilation in a system allowing unrestricted spontaneous breathing at any moment of the ventilatory cycle. It can also be described as a Continuous Positive Airway Pressure (CPAP) system with a time-cycled change of the applied CPAP level. As with a pressure controlled, time-cycled mode, the duration of each phase (T(high), T(low)) as well as the corresponding pressure levels (P(high), P(low)) can be adjusted independently. ⋯ Furthermore, spontaneous breathing of the patient does not necessitate any switching of the mode of ventilation. The transition from controlled to augmented ventilation is smooth. BIPAP enables the therapist to let the patient breathe freely even under the most invasive ventilation conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
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Inspiratory pressure support is a mode of partial ventilatory support which can be defined as patient-initiated, pressure-targeted and patient-interrupted. Addition of pressure support to a spontaneously breathing patient results in a reduction of respiratory rate and an increase in tidal volume. It corrects arterial blood gas abnormalities resulting from rapid shallow breathing and reduces the work of breathing. ⋯ Since it is not volume-targeted, variation in delivered ventilation may occur in unstable patients or in patients with fluctuations in respiratory drive. Clinical advantages have been found using pressure support during the process of weaning from mechanical ventilation in patients with prolonged difficulty in tolerating discontinuation from mechanical ventilation. Lastly, it can be delivered via a face-mask to avoid the need for endotracheal intubation in patients with hypercapnic respiratory failure.
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Editorial Historical Article
Mechanical ventilation in acute respiratory failure.
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Dynamic hyperinflation, also called intrinsic PEEP (PEEPi,) occurs particularly when high tidal volumes or high respiratory rates are used during mechanical ventilation, although the phenomenon does occur at normal tidal volumes. It is not identified using existing monitoring such as the airway pressure but can be identified by occlusion of the expiratory port before the onset of the next positive pressure breath. Many factors contribute to PEEPi which has unfavourable effects on respiratory muscle activity. ⋯ Fine tuning of positive pressure ventilation, using low tidal volumes, short inspiratory times and adequate inspired oxygen are required. External PEEP, up to but not exceeding PEEPi, may be advisable. PEEP may be used therapeutically to improve gas exchange by inverse ratio ventilation or high frequency jet ventilation.