critical care medicine
Airway and Respiratory Devices
Bag Valve Mask Devices
Bag-valve-mask devices consist of a self-inflating bag (resuscitator bag) with a nonrebreathing valve mechanism and a soft mask that conforms to the tissues of the face; when connected to an oxygen supply, they deliver from 60 to 100% inspired oxygen (see also How To Do Bag-Valve-Mask (BVM) Ventilation ). In the hands of experienced health care professionals, a bag-valve-mask device provides adequate temporary ventilation in many situations, allowing time to systematically achieve definitive airway control. However, if bag-valve-mask ventilation is used for Bag-valve-mask devices do not maintain airway patency, so patients with soft-tissue relaxation require careful positioning and manual maneuvers (see figuresand), as well as additional devices to keep the airway open. A: The head is flat on the stretcher; the airway is constricted. B: The ear and sternal notch are aligned, with the face parallel to the ceiling, opening the airway. Adapted from Levitan RM, Kinkle WC: The Airway Cam Pocket Guide to Intubation, ed. 2. Wayne (PA), Airway Cam Technologies, 2007. An How To Insert an Oropharyngeal Airway or a Absolute contraindications for placement of a nasopharyngeal airway include significant mid-face injuries with suspected cribriform plate (basilar skull) fracture. Relative contraindications include abnormalities in nasal anatomy (eg, significant nasal trauma, large polyps, recent nasal surgery) that could make passing a nasopharyngeal airway difficult. The most common way to determine the proper size of oropharyngeal airway is to use an airway that is the same length as the distance between the corner of the patient’s mouth and the angle of the jaw. Resuscitator bags are also used with artificial airways, including endotracheal tubes and supraglottic and pharyngeal airways. Pediatric bags have a pressure relief valve that limits peak airway pressures (usually to 35 to 45 cm water); practitioners must monitor the valve setting to avoid inadvertent hyperventilation. The relief valve can be shut off if necessary to provide sufficient pressure. 