critical care concepts Flashcards
(58 cards)
1
Q
What is the function of ventilation?
A
gas distribution into & out of the pulmonary airways
2
Q
What is the function of pulmonary perfusion?
A
blood flow from the rt side of the heart, through the pulmonary circulation & into the lt side of the heart
3
Q
What is diffusion?
A
gas movement from an area of greater to lesser concentration through semipermeable membrane
4
Q
What is ventilation?
A
- gas distribution in & out of the airways
- assesses the status of CO2
5
Q
How is blood oxygenated?
A
through perfusion
6
Q
What is the perfusion rate of the body?
A
The alveoli receive O2 at ~ 4L/min and the capillaries supply blood at ~ 5L/min
- this makes the V/Q ratio 4:5 or .8 (NOT a 1:1 ratio)
- This is only an average because the VQ ratio varies based on the body position & regions of the lung
7
Q
What happens when alveoli are less compliant?
A
we dont get as good of ventilation at the top of our lungs
8
Q
What is shunting?
A
- problem with decreased ventilation
- alveoli perfused but not ventilated
- allows deoxygenated blood to go into the left side of the heart & into the body
9
Q
What can cause shunting?
A
- congenital issues
- airway obstruction
- ARDS (acute resp distress syndrome)
- pneumonia
- atelectasis
- pulmonary edema
10
Q
What is dead space?
A
- problem is decreased perfusion (think trachea)
- when there is NOT enough or is a problem with blood in the lung becoming oxygenated
11
Q
What can cause dead space?
A
- pulmonary embolism
- pulmonary infarction
12
Q
What is a silent unit (silent lung)?
A
- problem with ventilation & perfusion
- there is shunting & dead space
13
Q
What can cause silent lung?
A
- ARDS (acute respiratory distress syndrome)
- pneumothorax
14
Q
What is hypoxemia?
A
Low arterial oxygen tension (in the blood)
- adversely affects every tissue in the body
supply & demand mismatch
- poor perfusion such as in ischemia
- decreased arterial oxygen, such as anemia
15
Q
How do tissues tolerate hypoxemia?
A
- skeletal muscle can recover after 30 minutes of hypoxemia
- brain cells can tolerate 4-6 min
- must provide oxygen until cause can be reversed
16
Q
What does hypoxemia cause?
A
- depletion of ATP
- acidosis
- damage to cells from noxious stimuli (ie. poison)
- abnormal calcium from noxious stimuli → calcium is supposed to go in the cell & come right back out → if it stays in the cell it will cause problems (this can happen when the cells are damaged)
- inflammatory response
17
Q
What is FiO2?
A
fraction of inspired oxygen (%); what is inhaled
- Room air is 21%
18
Q
What is PaCO2?
A
The partial pressure of CO2 in arterial blood
- it is used to assess the adequacy of ventilation
19
Q
What is PaO2?
A
The partial pressure of oxygen in arterial blood
- it is used to assess the adequacy of oxygenation
20
Q
What is SaO2?
A
arterial oxygen saturation measured from blood speciment (an ABG)
21
Q
What is SpO2?
A
arterial oxygenation saturation measured via pulse oximetry
22
Q
What is hypercapnia?
A
increased amounts of carbon dioxide in the blood
23
Q
What is hypoxia?
A
low oxygen level at the tissues
24
Q
What is tidal volume?
A
The amount of gas moving in & out of the lungs with each breath, measured in milliliters (6-10 mL/kg)
25
What is minute ventilation?
total amount of gas moving in & out of the lungs per min
- it is (volume) calculated by multiplying the tidal volume by RR, measured in liters per min
26
What is peak inspiratory flow rate (PIFR)?
The fastest flow rate of air during inspiration measured in liters per second
- gives us an idea of muscle function
27
What do artificial airways do?
- Establish an airway
- protect the airway
- facilitate mechanical ventilation
28
What are the kinds of artificial airways?
- oropharyngeal airway
- nasopharyngeal airway
- endotracheal tube
- Tracheostomy
29
What are airway adjuncts?
airway adjuncts → used to open the airway; when you are not ready to intubate yet
- oral airway → used to keep the tongue from closing off the airway; for patients with thicker necks
30
how is oxygen therapy delivered?
- all oxygen is 100% oxygen
- the amount a pt recieces depends on the delivery system
- when someone has decreased perfusion → need MORE oxygen
- when someone has decreased ventilation → need more FLOW (more pressure to get CO2 out)
31
How is FiO2 changed based on oxygen flow rates?
one liter of O2 provides 4% above RA & add 4% for each L/min
room air: .21 or 21%
32
What is low flow oxygen delivery?
- systems are specific devices that do NOT provide the pts entire ventilatory requirements
- Room air is entrained with the oxygen, thereby diluting the FiO2
- used in stable patients because not reliable in the delivery of oxygen
33
What causes variability in the oxygen delivery when using low flow oxygen delivery?
oxygen mixes with room air & the concentration of oxygen that can be delivered by nasal cannula varies
- pts RR
- tidal volume
- oxygen flow rate
- extent of mouth breathing
34
When can a face mask be used?
temporary use → b/c there is not ventilation control; we get room air
- can be used in a situation when you need quick oxygen (NOT long term use)
- about 40-50% FiO2
35
What does high flow oxygen do?
- systems are specifc devices that deliver the pts entire ventilatory demand, meeting or exceeding the pts peak inspiratory flow rate (PIFR), thereby providing an accurate FiO2
** can control ventilatory components**
36
What are the kinds of high flow oxygen delivery?
- CPAP
- BiPAP
- high flow NC
- ventilators
- non-rebreather mask
37
What is BIPAP?
** bilevel positive pressure oxygen delivery system**
- "pushes" air into the lungs
38
How can BIPAP be delivered & what are the side effects?
can be delivered by mask or cannula
- can be uncomfortable
- drying
- bloating
- eye irritation → almost looks like pink eye; need to incorporate proper eye hygiene to help prevent irritation
39
What does high flow NC help with?
can warm (to 37C) & humidify gas
- decreases airway inflammation
- maintain mucociliary function
- improve mucous clearance
- reduces caloric expenditure in acute respiratory failure
- better complicance than BiPAP or regular NC
- better O2 delivery
- some PEEP like characteristics → positive pressure
- decreased wash out & lowers CO2
40
What is a HFNC associated with?
- decreased RR
- decreased work of breathing
- better oxygenation than oxygen delivery by face mask
41
Who can HFNC be used for?
can be used in patients of all ages and with a variety of conditions, including premature infants with respiratory distress syndrome, infants with bronchiolitis, & adults with hypoxemic respiratory failure
42
How much oxygen can a non-rebreather mask give?
can deliver up to FiO2 95%
** as close to 100% oxygen as we can give**
43
What should you know about non-rebreather masks?
can also use N/C
- Highest O2 delivered on spontaneous breathing
- must assess the bag for deflation → should NEVER be completely deflated; this would indicate a problem with the rebreather
- it may decrease a little with inspiration but should be inflated → increase the dlow
- must be at 15L on the flow meter
44
What is pulse oximetry?
- used to measure the percentage of O2 saturation
-only measures perfusion
- does not measure ventilation → cannot solely rely on oxygen saturation to ensure the pt is properly ventilating/perfusing
45
What is the relationship between pulse ox & PaCO2?
- when pulse ox is 100% → correlates to a PaO2 of 100 as well
** NOT a linear curve** → Pulse ox reading may still look okay, but the patient’s PaO2 will drop more
46
What is needed to perform an intubation?
- laryngoscope → two types of blades: Macintosh or miller blades
- ETT & stylet → stylet provides stability & then is removed when tube is inserted
- bag valve mask (ambu bag)
47
What is the role of the nurse during intubation?
- explain to the pt what is happening → do NOT say "just relax"
- administer sedation → assess after sedation is given
- listen for bilateral breath sounds
- be certain chest x-ray is done
- maintain cuff volume
- maintain tube patency
- proper oral care
- aspiration precautions
48
What is propofol?
-sedative
- crosses BBB
- takes effect in 40 sec → lasts 6 minutes
- no analgesia → no pain relief
- can be used for longterm sedation → cardioversions; peds cases
49
What is etomidate?
- sedative
- safe for those with ICP; hypotension
- no analgesic effect → no pain relief
- rapid onset
50
What should we know about using benzos as sedatives for intubation?
- Midazolam can last 15-30 minutes
- romazicon → antidote to reverse all benzos
- can be combined with fentanyl
51
What is ketamine?
- used mostly in kids
- maintain respiratory drive
- sedation, analgesia, & amnesia
- can be combined with propofol
52
What does fenanyl due during intubation?
provides pain relief
53
What is dexmedetomidine (precedex)?
- sedation with preserved muscle tone & resp effort, spontaneous movement & easy arousal; allows the pt to obey simple instructions
- if we are concerned about neuro changes we do NOT have to think that the sedation is causing it
- given as infusion
- usually well tolerated but can cause → hypotension & bradycardia
54
What is ETCO2 monitoring (capnography)?
end tidal CO2 monitoring
- provides valuable information on CO2 clearance (typically 2-5mm lower than CO2)
ventilation:
- used to assess ETT placement → chest x-ray is gold standard
- early signs of compromise
- ventilatory status
- CPR → or if the pt is coding
55
When is pneumonia considered ventilator acquired pneumonia?
considered after pt has been intubated for 48-72 hrs
56
What nursing interventions help prevent ventilator acquired pneumonia?
**hand hygiene**
- HOB elevated 30-45 degrees
- suctioning secretions in the oral cavity
- Drain water collecting in the tubing
- mouth/oral care regularly
- sedation vacation
- daily assessment of readiness for extubation
peptic ulcer prophylaxis
- DVT prophylaxis
57
Who is a tracheostomy for?
Those requiring prolonged ventilatory care have 50-60% mortality in 1 year → begin discussion around day 30
**Evidence is NOT clear on who benefits best**
- high likelihood for survival
- neurologic injury seems to do better with trach
decision for trach depends on each person
58
Where do pts on chronic mechanical ventilation usually reside?
discharging pt on ventilators → long-term care → home care
