Oxygenation Flashcards
Define pulse oximetry
- Transcutaneous measurement of light wavelengths to calculate arterial oxygen saturation
- Oxygenated and deoxy blood have differing absorption of light spectra
Define capnography
- Monitoring of CO2 levels via nasal cannula (normal is 35-37 mm Hg)
- Frequently used during moderate sedation
Proper size of nasopharyngeal airway?
Tip of nose to tragus of ear
Proper size of oropharyngeal airway?
Corner of mouth to angle of mandible
When is a nasal cannula indicated?
Mild hypoxia (91-94%) (delivers 1-6 L/min)
When is a non-rebreather mask indicated?
Moderate hypoxia (86-91%) (delivers up to 15 L/min)
Advantages of non-rebreather mask
Able to deliver high volume of O2 without risk of rebreathing patient’s own CO2
When is a Venturi mask indicated?
COPD patients
PO2 86-91%
Advantages of Venturi mask
Able to fix a concentration of oxygen
What is non-invasive ventilation?
- BiPAP and CPAP
- Pressurized oxygen delivery devices which provide support in early respiratory failure
Describe BiPAP
- Cycles b/w a targeted peak inspiratory pressure and a lower expiratory pressure
- Ventilation varies with patient effort
Indications for BiPAP
COPD, asthma, CF, PNA, sleep apnea
Describe CPAP
Delivers a static airway pressure maintained throughout inspiratory and expiratory cycle
Indications for CPAP
Same as BiPAP but PREFERRED for CHF and sleep apnea
Describe intubation
Placement of endotracheal tube orally for direct ventilation
Define rapid sequence intubation (RSI)
Intubation including sedation and paralysis
Indications for intubation
- Inability of pt to protect own airway
- Failure to oxygenate
- High potential for deterioration
- Pt/staff safety
MC meds used in intubation
- Etomidate (sedative)
- Succinylcholine (paralytic)
Describe hyperbaric oxygen therapy
Administration of 100% oxygen under pressure, usually 2.5x higher than normal atmospheric pressure
Purpose of hyperbaric oxygen therapy
- Blood can be hyperoxygenated by dissolving O2 within the plasma
- O2 carried to areas where circulation is diminished/blocked
What readings are WNL for pulse oximetry?
95-100% (with a good waveform)
Uses of nasopharyngeal airway
- Diminished gag
- Trismus
- Oral injuries
- Intoxication
When is an oropharyngeal airway used?
Spontaneous breathing but no gag
What does an oropharyngeal airway do?
- Holds tongue off posterior pharyngeal wall
- Provides opening for air/suction
What is applied after insertion of oropharyngeal airway?
O2 mask
Advantages of nasal cannula
- Talk, eat, drink w/o removing cannula
- Mouth breathing is possible w/o affecting function
Disadvantages of nasal cannula
Irritation to nasal mucosa both by dry oxygen and physical abrasion (causing epistaxis or rhinitis)
What does a non-rebreather mask contain?
Oxygen reservoir with one way CO2 valve
Disadvantages of non-rebreather mask
- Claustrophobia
- Difficulty speaking/eating
Adverse effects of non-invasive ventilation
- Anxiety (pt may strain and increase work of breathing)
- Decreased CO (d/t increased intrathoracic pressure)
- Barotrauma
- Gastric distention
Importance of pre-procedure passive oxygenation?
Extends duration of safe apnea via de-nitrogenating the residual capacity of the lungs (which maximizes O2 storage within the lungs)
Define safe apnea
Time until a patient reaches a saturation level of 88-90%
How should a pt be positioned for pre-procedure passive oxygenation?
External auditory meatus on same horizontal plane as sternal notch (approx 20 degrees from horizontal)
(OR reverse Trendelenburg)
