Oxygen Delivery Devices PDF

‫كلية بالد الرافدين الجامعة‬ ‫قسم التخدير‬ ‫المرحلة الثالثة‬ ‫‪anesthetic equipment‬‬ ‫‪oxygen delivery devices‬‬ ‫تقنيات اجهزة التخدير‬ ‫اعداد‪ :‬م‪.‬م‪.‬عمار حوم‬ Oxygen delivery devices Currently, a variety of delivery devices are used. These devices differ in their ab...

‫كلية بالد الرافدين الجامعة‬ ‫قسم التخدير‬ ‫المرحلة الثالثة‬ ‫‪anesthetic equipment‬‬ ‫‪oxygen delivery devices‬‬ ‫تقنيات اجهزة التخدير‬ ‫اعداد‪ :‬م‪.‬م‪.‬عمار حوم‬ Oxygen delivery devices Currently, a variety of delivery devices are used. These devices differ in their ability to deliver a set fractional inspired oxygen concentration (FiO2). The delivery devices can be divided into variable and fixed performance devices. The former devices deliver a fluctuating FiO2, whereas the new devices deliver a more constant and predictable FiO2.  Variable performance masks (medium concentration; MC) These masks are used to deliver Oxygen-enriched air to the patient. They are also called low-flow delivery devices. They are widely used in the hospital because of greater patient comfort, low Cost, simplicity and the ability to manipulate the FiO2 without changing the device for the same patient. These systems have a limited reservoir capacity, SO in order to function appropriately, the patient must inhale some ambient air to meet the inspiratory demands. The FiO2 is determined by the oxygen flow rate, the size of the Oxygen reservoir and the respiratory pattern. Variable performance face mask Components: 1. The plastic body of the mask with side holes on both sides. 2.A port connected to an oxygen supply. 3. Elastic band(s) to fix the mask to the patient's face. Problems in practice and safety features These devices are used only when delivering a fixed oxygen concentration is not critical. Patients whose ventilation is dependent on a hypoxic drive must not receive Oxygen from a variable performance mask. Nasal cannula Nasal cannula are ideal for patients on long-term oxygen therapy. A flow rate of 24 L/min delivers an FiO2 of 0.28-0.36 respectively. Higher flow rates are uncomfortable. Components 1. Two prongs which protrude about 1 cm into the nose. 2.These are held in place by an adjustable head strap. Nasal cannula Mechanism of action 1.There is entrainment of ambient air through the nostrils. The nasopharynx acts as a reservoir. 2. The Fi02 achieved is proportional to: a) the flow rate of oxygen b) the patient's tidal volume, inspiratory flow and respiratory rate. c) the volume of the nasopharynx. 3. Mouth breathing causes inspiratory air flow. This produces a Venturi effect in the posterior pharynx entraining oxygen from the nose. 4 There is increased patient compliance with nasal cannula Compared to facial oxygen masks. The patient is able to speak, eat and drink. Problems in practice and safety features The cannula and the dry gas flow cause trauma and irritation to the nasal mucosa. They are not appropriate in patients with blocked nasal passages. Nasal catheters Nasal catheters comprise a single lumen catheter, which is lodged into the anterior naris (nostril) by a foam collar. Oxygen flows of 2-3 L/min can be used. The catheter can be secured to the patient's face by using tape. It should not be used when a nasal mucosal tear is suspected because of the risk of surgical emphysema. Nasal catheter Open Oxygen delivery systems These are designed to offer the maximum comfort to patients while delivering variable FiO2 concentrations. They fit around the patient's head like head phones, so making minimal physical contact. Such systems are suitable for both nasal and mouth breathing patients. They may be more suitable for patients on long-term oxygen therapy. A wide range of fresh Oxygen flows can be used, so delivering a variable performance. As with the other devices of this kind, similar factors will affect its performance. Open oxygen delivery Fixed performance devices VENTURI MASK These masks are fixed performance devices (sometimes called high-air- flow Oxygen enrichment, or (HAFOE). Components 1. The plastic body of the mask with holes on both sides. 2. The proximal end of the mask consists of a Venturi device, The Venturi devices are colour- coded and marked with the recommended oxygen flow rate to provide the desired oxygen concentration. 3. Alternatively, a calibrated variable Venturi device can be used to deliver the desired Fi02. VENTURI MASK Mechanism of action 1. As the flow of oxygen passes through the constriction, a negative pressure is created. This causes the ambient air to be entrained and mixed with the Oxygen flow. The FiO2 is dependent on the degree of air entrainment. Less entrainment ensures a higher FiO2 is delivered. This can be achieved by using smaller entrainment apertures or bigger windows to entrain ambient air. The smaller the orifice is, the greater the negative pressure generated, so the more ambient air entrained, the lower the Fi02. The oxygen concentration can be 0.24, 0.28, 0.31, 0.35, 0.4 or 0.6. Problems in practice and safety features 1. These masks are recommended when a fixed oxygen concentration is desired in patients whose ventilation is dependent on their hypoxic drive, such as those with chronic obstructive pulmonary disease. However, caution should be exercised as it has been shown that the average FiO2 delivered in such masks is up to 5% above the expected value. 2. The Venturi mask with its Venturi device and the oxygen delivery tubing is often not well tolerated by patients because it is noisy and bulky. Anesthetic breathing systems are other examples of the fixed performance devices. Thank you