Supplemental Oxygen & Mechanical Ventilation Flashcards
ABG - pros and cons
VBG- pros and cons
ABG
pros
- arterial stick –> pre-capillary thus you get a good oxygenation level reading (since its before it diffuses into the tissues) and gives a good idea about ventilation (since its pre-capillary)
cons
-need to aterial stick – which isnt consistenly avalible
VBG: venous
pros
- more readily avalible because the IV sight is already established
- a good “spot check” for ventilation status
cons
- it is post-capillary so its less reliable
- poor abilit to assess oxygenation status
- higher PCO2 and lower pH since its post-cap than the ABG
what is pulse ox? what is end-tidal CO2? what do they each measure?
pulse ox
- a good read of oxygenation ONLY
- uses spectophotometry tp measure SpO2 (92-100% normal)
EtCO2
- the partial pressure of CO2 exhaled in breaths
- attached to the end of a nasal canula or endotrachial airway
- normal = 35-45 mmHg (which is normal varterial CO2)
- good for assessing ventilation, sedation , resp. distress, etc.
what is hypoxic respiratory failure? what is hypercapnic? how are they different
Hypoxic Respiratory failure
- a problem with oxygen getting from the alveoli to the circulation –> lower airways issue of parynchma and alveoli
- pnumonia
- pulmonary edema
- ILD
- ARDS
- atelectasis
- COPD,Asthma
hypercapic respiratory failure
- a problem with not being able to get rid of CO2 –> airway obstruction, drop in ventilation
- - AMS
- drug intoxication
- neuromusc. disease
- rib fracture
- obestiy
- COPD
- scolosis
what is hypoxic respiratory failure? what is hypercapnic? how are they different
Hypoxic Respiratory failure
- a problem with oxygen getting from the alveoli to the circulation –> lower airways issue of parynchma and alveoli
- pnumonia
- pulmonary edema
- ILD
- ARDS
- atelectasis
- COPD,Asthma
- shunting causes hypoxia
hypercapic respiratory failure
- a problem with not being able to get rid of CO2 –> upper airway obstruction, drop in ventilation (unable to take big enough breath, exhale it out)
- - AMS
- drug intoxication
- neuromusc. disease
- rib fracture
- obestiy
- COPD
- scolosis
dead-space ventilation causes hypercapnia
what is hypoxic respiratory failure
- a PaO2 < 60 mmHg
- or an abnormal PaO2 to FiO2 ratio (P:F)
use suppl. O2 when
- signs of hypoxia
- SpO2 < 92%
- PaO2 < 60 mmHg
signs and symptoms of hypoxia? hypercapnia?
hypoxia
- anxiety, agitation, SOB
- increased work to breath and accessory muscle use
- cyanosis (seen ONLY in hypoxia)
- diphoresis
- tachypnea
hypercapnia
- somnolence, obtuned
- SOB
- increased work to breath OR decreased work
- fast or slow breath (tachy or bradypnea)
what are the two components you must consider when putting a pt. on a non-invasive o2 supplement?
FiO2: fraction of O2 (%) they are taking up
flow: (L/min) how fast the O2 is flowing into the pt.
- increase flow may help offload the pt. work of breathing
what are the two components you must consider when putting a pt. on a non-invasive o2 supplement?
FiO2: fraction of O2 (%) they are taking up
flow: (L/min) how fast the O2 is flowing into the pt.
- increase flow may help offload the pt. work of breathing
Nasal Cannula v. High-Flow NC
NC: can go up to 6L/min of O2
- you can only adjust the FLOW of the O2, cannot adjust the % FiO2
- the FiO2 will be 4% per L of air (added to the % in the normal air of 21%)
atmospheric FiO2 + 4%(flow in L/min) = amount of %
High-Flow NC: you can adjust FLOW and FiO2%!!
- up to 60L/min
- up to 100% FiO2
Venturi-Mask V Non-Rebreather
v Re-Breather
Home Oxygen Concentrator
Venturi Mask
- “air-entrainment” uses a jet force to adjust teh velocity and FiO2
- flow : 2-15L/min
- FiO2: 24-50%
Non-rebreather
- bag can fill to 100% FiO2 with one way valve so exhlaed air doesnt mix!!
- flow: up to 15L/min
- FiO2: 60=100%
Re-Breather
- mixes the exhaled and inhaled air in the bag
- dilution of the O2 concentration so not as high of a %
Oxygen Concentrator – the purse
- at home for taking air and purifing it to just oxygen outpt.
briefly describe the process of normal ventilation & how this is different from mechanical ventilation
normal ventilation — controlled by negative pressure breathing
- we create negative pressure in teh pleural space which causes the lungs to expand and draw air in — reliant on a shift in internal and external pressure
in mechanical ventilation – the pressure forces are driven by positive pressure breathing in that the force of air traveling in acutally forces the expansion of the lungs
both rely on….
1. oxygenation: providing adequate O2 for metabolism
2. ventliation: removal of Co2 from the blood and tissues
how do the following vent settings play a role in oxygenation or ventilation
PEEP
FiO2
TV
RR
oxygenation: getting O2 to the tissues –> get O2 to the pulm. interface
PEEP & FiO2 play here
PEEP: positive end expiratory pressure – the amoutn of pressure whih remains within the alveoli to keep them open after exhaliation
FiO2:the % of O2 that is delivered
ventilation: getting the CO2 out which relys on minute ventliation (vent. in 1 min)
TV & RR play here
TV x RR = MVe
Tv: amount of air which is taken in and out (how big)
RR: rate of breaths (how fast)
when is mechanial ventilation indicated? what pts.?
- hypoxic respiratory failure and supp. O2 is not helping
- hyercarbic respiratory failure (need help exhaling the Co2)
- too much work of breathing
- inability to protect the airway
- severe shock
- severe acidosis
- respiratory muscle fatigue
- secretiosn cause airway issue
when is non-invasive postive pressure ventilation indicated? CPAP and BiPAP
benefits?
- pt. awake enough to tolerate
- pt. agitated to tolerate
- ability to protect airway
- clincial trajectory pointing where they would need invasive vent?
- ideally: want to put those who look like they could clincially miprove in 24-72 hours to be put on these machines (quick turn around)
–pulmonary edema
copd exacerbation
astham exacerbation
benefits
- avoid trauma in upper airway
- decrease infection risk
- reduced need for sedation
- potential short stay
when is CPAP used? how does it work? settings on the machine?
what about BiPAP??
Continuous Positive Airway Pressure
- continuous pressure to open the upper airway and recruit more alveoli to participate in gas exchange
- settings : FiO2 ( up to 100%) and EPAP(like PEEP) the pressure
- USED FOR HYPOXIA!!!!!
bilvel postive pressure (biPap)
- USED FOR HYPERCAPNIA and breathing work load to decrease
- creates a pressure gradiant between two pressures
- increases tidal volume and increases ventliation therefore to increased the removal of CO2
- has inspiratory flow then assists in the expiratory phase
- settigs: EPAP and IPAPA & FiO2%
when is CPAP used? how does it work? settings on the machine?
what about BiPAP??
Continuous Positive Airway Pressure
- continuous pressure to open the upper airway and recruit more alveoli to participate in gas exchange
- settings : FiO2 ( up to 100%) and EPAP(like PEEP) the pressure
- USED FOR HYPOXIA!!!!!
bilvel postive pressure (biPap)
- USED FOR HYPERCAPNIA and breathing work load to decrease
- creates a pressure gradiant between two pressures
- increases tidal volume and increases ventliation therefore to increased the removal of CO2
- has inspiratory flow then assists in the expiratory phase
- settigs: EPAP and IPAPA & FiO2%
what to consider when deciding to intubate
- failutre to maintain airway or protect airway
- failure to achieve desired goals witht eh current respiratory support of teh pt.
- illness expected to worsen within next 24-48 hours
two basic mechanial vent. modes
assist control and pressure support
assist control: the machine is deciding the rate, rhythm and what types of breath they are taking
- the PEEP, RR and FiO2 will be set
- NON-SPONTANEOUS breathing
pressure support: SPONTANEOUS ventliation
- the pt. decides how often and what type of breath is going (via brain) and then the vent. will assist this
- alwasy set a PEEP FiO2 and pressure support level
AC/VC vs. AC/PC ventialtion modes
AC/VC: Volume control
- the VOLUME is set by the machine –> which then impacts the pressure that is forced into the pt. (dependent variable)
- TV, RR, PEEP & FiO2 are set
- can control the TV/RR to completely control the MVe
- we dont control the pressure –> cane lead to barotrauma
AC/PC: pressure control
- we set the PRESSURE in the machine –> when then impacts the volume of the breathing (dependent)
- set RR, IPAP, EPAP, FiO2
- we can control the pressure (reduce barotrauma)
- the TV will vary based on pt. and we have less contorl as to MVe
what is pressure SUPPORT ventilation? when is it used
pressure Support vent:
- pt. triggers the inspiration – the vent kicks in and assists with the breath by influx pressure
- contorl PS, PEEP, FiO2
- PS titrated to pts. RR and work of breathing
- ** use to help wean pts. on vents**
- use for those who are only vented for airway protection – their lungs are fine and their acid lvels are fine
what is SIMV vent?
synchronied intermittenet mandatory vent
- a combo of pressure and volume support breathing
- sets a vent pressure to breathe
- but if the pt. breathes it will just support the volume of the breath – influ the volume without forcing the pressure
define the following terms & how they are used in mechanical vent settings
- Tidal volume
- Peak airway pressure
- plateau pressure
- PEEP (total PEEP and auto-PEEP)
- inspratory-experiatory ratio (I:E ratio)
tidal volume: amount of air going in and out –> on a vent we want to have lung protecting ventilatio – aim for 6-8cc/kg of boydweight
peak airway pressure: the maximum pressure the airways sees during a respiration cycle
plateua pressure: the maximum amount of pressure the alveoli will see during a ventilation cycle
total PEEP: the pressure the alveoli will see at the end of expiration (what remains in the alveoli)
auto-PEEP: “stacking” of peep pressures becuase the pt. is not fully exhaling the pressures will continuoulsly increase
I:E ratio: normal breathing is 1:2 but if theres a problem with auto-PEEP can change that to allow a longer expiration to ensure air is being released
what do you need to consider when weaning someone from a vent?
- is the FiO2 requirement improving? ( they should need less than 50% FiO2)
- is the underlying disease process improving
- are we able to ween off of a high PEEP
- are we able to ween of sedation enough for the pt. to have a respiratory drive
what do we check for prior to extubation
- underlying disease process improving
- spontaneous breathing trial: we have very minial intubation settings assisting the breath (low pressue) for 20 mins to see how they do
- –> calculate the ^ with a Rapid-Shallow Breathing Index < 105 indicates a successful intubation
RSBI: RR(f)/TV
- check mental status (awake alaert and following commands)
- airway secure and safe
- secretion management
