2 respiratory support Flashcards
General methods / options for respiratory support?
- o2 therapy
- positive pressure ventilation
- humidification of inspired gases
- aerosol therapy
What is the primary indication for o2 therapy?
hypoxia
What are some conditions that may lead to hypoxia?
- inadequate inspired o2
- impaired pulmonary function
- ineffective o2 transport
- inc o2 demand [NOT met by normal o2 delivery]
What are objective measures to determining the need for o2 therapy in a patient?
And subjective signs?
- arterial blood gas (PaO2
What are some methods for o2 administration?
- face mask/flow by/nasal prongs
- baggie, e collar, hood
- o2 cage, chamber, tent
- intranasal catheter
- intratracheal catheter
- nasotracheal catheter
- endotracheal tube
- tracheostomy tube
When might an oxygen tent be employed?
- patient is sedated or depressed
- short term use
- often immediately post op
Some benefits to intranasal o2 supplementation?
a down side?
- have more control over % o2 animal is getting
- designed for more extended care
- more secure
- anchor tubes so more invasive
When inserting a intranasal tube, what is landmark on face of animal to measuring the length of the tube?
What is the basic procedure?
- medial canthus of the eye (or level of upper 4th pre molar)
- deaden area, measure tube, mark tube, puncture lateral canthus of nose with needle, put suture through needle, tie a square know, INSERT TUBE INTO VENTRAL MEATUS, thread straight, surgeon’s knot around top then secure suture to top of patient’s head
general procedure to intratracheal o2 supplementation?
- clip and prep neck
- caution to NOT introduce environmental pathogens
- puncture directly into trachea w/o filtration of nose first
B/c the filtration of the nose is lost with intratracheal o2 supplementation, what special consideration should be made?
flow rates slower than when tube goes into nose
also a softer catheter is used
when comparing intranasal vs intratracheal o2 administration, which yields more o2 delivery?
intratracheal
direct delivery into the trachea is same o2 flow rate but 1.5x more o2 reaches lungs - better effects
What is the main guideline for o2 administration?
- flow rates
- resultant FiO2 and PaO2
- the clinical patient’s physiological state may dictate higher or lower flow rates
What is the upper limit to PaO2 typically?
What situation is an exception?
- above 100 mmHg usually has limited benefit b/c SaO2 is 97%+ [Hb is saturated at this point}
- except in SIRS [patient needs all the help it can get and may rely on o2 dissolved in blood, whereas most patients only benefit from o2 on Hb]
Why is trachea delivery of o2 more efficient method?
- trachea serves as oxygen rich reservoir
- lower flow rates are more economical
Factors to influence choice btwn IN (nasal) or IT (tracheal) administration of o2?
- clipping and aseptic prep req for IT placement
- nasal trauma or dz may preclude use of IN tube
- upper airway obstruction must be INCOMPLETE to use IT o2 b/c obstruction may px escape of excessive IT flow
prolonged levels of what % o2 can lead to oxygen toxicity?
50-60%
How to monitor o2 therapy?
- clin signs: resp rate, character of resp, mucous mem color
- pulse oximetry
- arterial blood gas
describe function of pulse oximeter
- commonly used
- probe on tongue in anesthetized patient
- one side has diode that emits red and infrared light and other side has detector - light is sent through tissues and detected on the other side
What does the value from a pulse oximeter tell you?
- % of oxygenated Hb in Aa
- equal to SaO2 in arterial blood gas
Guidelines to weaning a patient off oxygen therapy:
- monitor clin signs
- monitor SpO2
- serial arterial blood gas
- trials off 02: re institute o2 administration as indicated and see if clin signs come back
