Page 57 - Critical Care Nursing Demystified

42 CRITICAL CARE NURSING DeMYSTIFIED

TABLE 2–5 O Delivery Devices and Percentages of O Delivered
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Device O Delivery Percentages
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Nasal cannula (nc) Use at 2 L per minute gives flow rate of 28%.
Simple mask Use at 6–12 L per minute gives 35%–50%.
Venturiʼs mask Use at 15 L per minute gives 24%–50%.
Partial rebreather Use at 6–10 L per minute gives 40%–60%.
Nonrebreather Provides concentrations from 60% to 90%.

1. Nasal cannula
These are two short, hollow prongs delivering direct oxygen into the nos-
trils. The prongs attach to tubing that connects to an oxygen source, a
humidifier, and a flow meter. Benefits of this type of delivery system in-
clude a comfortable, convenient method of O delivery in concentrations
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up to 44%. The equipment is less expensive, allows for patient activity/
mobility, and is a practical system for long-term use. Disadvantages in-
clude the inability to deliver oxygen concentrations over 44%; it cannot
be used if the patient has nasal problems; and a liter flow greater than 6 Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
L will not increase the FiO and can dry out the nasal passages.
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NURSING ALERT

Monitor equipment daily. Evaluate for pressure sores over ears and cheek areas. Pad-
ding can be applied to reduce friction in these areas. A water-soluble lubricant can
be used to prevent nasal irritation. Avoid kinking or twisting of the tubes, which will

impede the flow of oxygen.

2. Simple face mask
This mask fits over the nose and mouth and is held in place by an elastic
around the head. The mask is attached to O tubing, a humidifier, and a
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flow meter. Benefits include the delivery of higher O concentrations as
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compared to the nasal cannula. The system does not tend to dry out the
mucous membranes of the nose and mouth. Disadvantages include a con-
fining mask may increase anxiety in some patients and can cause facial
irritation if applied too tightly. It is difficult to talk and be understood and
the airway must be protected in case emesis occurs. The simple face mask
is contraindicated for patients with long-term CO retention. CO retainers
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breathe in response to a low O level. Flooding the patient’s respiratory
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