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Equipment and monitoring
Published in Brian J Pollard, Gareth Kitchen, Handbook of Clinical Anaesthesia, 2017
Baha Al-Shaikh, Sarah Hodge, Sanjay Agrawal, Michele Pennimpede, Sindy Lee, Janine MA Thomas, John Coombes
APRV (Airway Pressure Release Ventilation). The ventilator cycles between two pressure levels (upper and lower pressure levels). Baseline airway pressure is the upper level, with pressure intermittently being released to allow removal of waste gases.
Pediatric ICU management
Published in David E. Wesson, Bindi Naik-Mathuria, Pediatric Trauma, 2017
Jason O. Robertson, Adam M. Vogel
Airway pressure release ventilation (APRV) can be thought of as delivering two different levels of CPAP, one “high” and one “low”, with a set release time. It maintains a high airway pressure for the majority of the cycle and periodically releases to a set PEEP to allow ventilation. Since a greater amount of time is spent in “inspiration,” it is a type of inverse ratio ventilation. APRV allows spontaneous breathing throughout the entire cycle and improves alveolar recruitment by increasing the mean airway pressure. As with any PC mode of ventilation, the patient remains at risk for injurious VTs or, conversely, ineffective ventilation if lung compliance changes. While there is not much data to advocate use of this mode over others in the pediatric population [47], there is some evidence that it may prevent the development of ARDS in high-risk adult trauma patients [48].
Inhalation Injury
Published in Stephen M. Cohn, Matthew O. Dolich, Kenji Inaba, Acute Care Surgery and Trauma, 2016
This is the rationale for the use of high-frequency percussive ventilation by means of the volumetric diffusive respiration (VDR-4®) ventilator (Percussionaire, Sandpoint, ID). This device is different from high-frequency jet or oscillation ventilators. It combines both subtidal, high-frequency (e.g., 400–1000 breaths per min) and tidal, low-frequency (e.g., 0–20 breaths per min) ventilations (Figure 34.1). With the VDR-4, gas exchange at lower peak and mean airway pressures occurs as a result of a variety of mechanisms, to include more turbulent flow and enhanced molecular diffusion [23,24]. Unique to the VDR-4, the high-frequency, flow-interrupted breaths effect dislodgement of debris and cause its retrograde expulsion out of the airways. For this reason, we partially deflate the endotracheal tube cuff (to a minimal leak level) and frequently suction the oropharynx, as plugs and secretions in II patients can be copious. Finally, VDR-4, like airway-pressure release ventilation (APRV, also known as bi-level ventilation) enables spontaneous ventilation throughout the inspiratory and expiratory phases. In most cases, this improves patient–ventilator synchrony, and as in APRV may have other beneficial effects on gas distribution and respiratory muscle strength. The main disadvantage of the VDR-4 is the extra training required of nurses and respiratory therapists in its operation.
A comprehensive review of the use and understanding of airway pressure release ventilation
Published in Expert Review of Respiratory Medicine, 2020
Airway pressure release ventilation (APRV) is a mode of ventilation that has been used since the 1980s, most commonly as a rescue approach for patients with ARDS and inadequate oxygenation [1]. The goal of APRV is to maximize and maintain lung recruitment while avoiding both overdistension and collapse, based on the open-lung concept [1–3]. Typically, not viewed as a primary ventilation mode, it is instead usually considered to be an alternative approach for patients who fail more traditional modes of conventional mechanical ventilation (CMV) in neonatal, pediatric, and adult populations. However, APRV’s use as a primary mode of ventilation has been gaining acceptance, particularly when applied early in the course of respiratory failure, as it may play a role in ARDS prevention [4–7] There continues to be a lack of consensus amongst critical care clinicians regarding its clinical indication and efficacy due to a dearth of consistent evidence. There is also wide variability in how APRV settings are established and titrated, leading to an inconsistent methodology that makes appropriate retrospective analysis problematic [8]. This review will discuss the history of APRV, ventilator approach, rationale for its use, recent studies pertaining to its use in adult and pediatric patients, and potential future directions.