Lecture 19: Normal and Abnormal Pulmonary Physiology Flashcards
normal SpO2 and PaO2
SpO2 = 95-100%
PaO2 = 80-100 mmHg
SpO2 of 90% correlates with PaO2 of 60 mmHg (minimum O2 concentration to prevent ischemia)
what is the saturation of peripheral O2 (SpO2)
% of Hgb bound to O2
non-invasive measurement
measures how much O2 is being delivered to tissue
not as exact a measurement
what is partial pressure of O2 (PaO2)
partial pressure of dissolved O2 in arterial blood
requires arterial blood gas draw lab
reflective of the balance of O2 delivery and consumption
most accurate way to determine effectiveness of blood oxygen saturation
normal respiratory rate
12-18 breaths per min at rest (some references say 12-20)
regular rhythm and non-labored effort
tidal volume ~500mL
no audible sounds
Eupnea = normal breathing rate and pattern
normal pulmonary vital signs
SpO2 = 95-100%
PaO2 = 80-100 mmHg
Respiratory Rate = 12-18 bpm
what is B type natriuretic peptide (BNP), normal ranges, and indication
a cardiac biomarker
normal <100 pg/mL
released in response to ventricular stretch or worsening heart failure
normal Hemoglobin (Hgb), lab category, and indication
a CBC value
normal (g/dL):
M = 14-18
F = 12-16
Hgb transports O2
normal blood gas values and indications
pH = 7.35-7.45
PaO2 = 80-100 mmHg
PaCO2 = 35-45 mmHg
HCO3 = 22-26 mEq/L
all portions that control normal blood chemistry for optimal physiological function
normal SpO2 response to exercise
initial transient drop when exercise starts
increase in respiratory rate brings back SpO2 back to stable/normal levels with increasing work load
SpO2 may increase with long duration tasks as steady state is reached
respiratory rate normal response to exercise
gradual increase with increased workload
maintains a steady state with minimal change at steady state exercise
rapid rise after/if anaerobic threshold (VT2) is reached
normal lung volume response to exercise
increases linearly with work
tidal volume increases to meet the demands of exercise and can approach vital capacity volumes
physiological progression that happens with respiration during exercise
mm cell respiration increases; more O2 is used; increase in CO2
brain detects increase in CO2; CNS signals lungs to increase RR
increased RR and volume of each breath; increase in gas exchange occurs
CNS signals heart to increase HR so more blood is pumped to the lungs for gas exchange
increased O2 gets sent to the mm to balance supply and demand
increased CO2 removed from blood and blown off via increased RR
vital signs that are concerning with a pulmonary patient
SpO2 <90% at rest or acute change in O2 demand/device
RR <10 or >30 at rest or unable to maintain conversation
HR <50 or >120 at rest or an uncontrolled/new arrhythmia
BP >180/90, <90/60, or MAP <60
what could potentially cause hypoxemia/hypoxia in a pt
heart/lung disease
hypoventilation
infection
anemia
carbon monoxide poisoning
PE
V/Q mismatch
sleep apnea
airway obstruction
high altitude
what is hypoxemia vs hypoxia
hypoxemia = low blood O2 levels measured by SpO2 or PaO2 (blood)
hypoxia = under oxygenation of tissues that impair cellular metabolism (cellular)
symptoms of hypoxemia
HA
dyspnea
tachycardia
coughing
wheezing
confusing, AMS
cyanosis of fingers, lips
symptoms of hypoxia
restlessness
HA
confusion, AMS
tachycardia
anxiety
tachypnea
dyspnea
symptoms of SEVERE hypoxia
bradycardia
extreme restlessness
cyanosis
what is bradypnea
decreased RR
due to sleep, drugs, metabolic disorder, or CNA/ABI
what is tachypnea
increased RR
due to fever, anxiety, shock, exercise, or pathology
what is apnea
absence of breathing
due to death
what is hyperapnea
normal rate but deep respirations
due to emotional stress or diabetic ketoacidosis
what is cheyne-stokes breathing pattern
gradual increase and decrease in respirations with periods of apnea
due to increase in inter cranial pressure, brain stem injury
what is atonal breathing pattern
apnea with periods of inconsistent respirations
due to actively dying, sever CVA/ABI
what is a restrictive lung volume
decreased vital capacity (VC) and total lung capacity (TLC)
biggest limitations to functional endurance are decreased inspiratory reserve volume (IRV) and expiratory reserve volume (ERV)
what is obstructive lung volume
increased vital capacity (VC) and total lung capacity (TLC)
biggest limitations to functional endurance are increased expiratory reserve volume (ERV) and residual volume (RV)
abnormal SpO2 response to exercise
persistent or ongoing drop in O2 with increasing work load
increasing supplemental O2 delivery to maintain homeostasis
**important to know individual pt O2 goals before making clinical decision to top activity or reduce intensity
abnormal RR response to exercise
drop in respiratory rate with work
rapid increase in RR that does not match intensity of workload
use ability to maintain ongoing conversation as a measure of how close the pt is to VT2
basic principles of O2 delivery
supplementing hypoxemia with added O2 to keep SpO2 within safe limits
observe trends and amounts of supplemental O2
be able to maintain supplemental O2 for pt during mobility
awareness of PT role in ability to titrate/adjust O2
flow rate vs concentration of O2
flow rate = how fast air is being delivered, expressed in L/min
concentration = the FiO2 of O2, expressed as %
the higher the FiO2, the faster it needs to be delivered
what is FiO2
fraction of inspired oxygen
represents % of inhaled air that is O2
atmospheric air ~21% O2, so FiO2 is 21%
every 1 L/min above room air (RA) adds ~4% FiO2
FiO2 usually rounded down to 20% for ease
list the flow rate in L/min corresponding to FiO2%
0 L/min = 20%
1 L/min = 24%
2 L/min = 28%
3 L/min = 32%
4 L/min = 36%
5 L/min = 40%
6 L/min = 44%
describe a nasal cannula
delivers O2 1-6 L/min; “low flow”
does not require added humidification
can only change flow rate
describe a face mask O2 delivery
can deliver 6-12 L/min
does not require humidification
can only change flow rate
describe a high flow nasal cannula
can deliver 6-15 L/min for some types
requires humidification added since air is moving faster
inner lumen of cannula is patterned to direct high air flow to ensure it reaches pt
describe heated high flow nasal cannula
up to 60 L/min and 100% FiO2
heated humidification helps protect airways and keep secretions thin
describe a venturi mask
can provide up to 60% FiO2
adapter sets flow based on set FiO2
can only titrate FiO2
describe a non-rebreather
1-15 L/min
mask covers nose and mouth to deliver very high O2 concentration
one way valves allow escape of exhaled CO2 to allow pure O2 on next inhalation
