Pulmonary Disorders lecture Flashcards
Functions of the lungs
- filtration by hair, mucus, cilia
- warm air to 37 deg. C
- humidify air to 100% saturation
- metabolism
Functions of the lungs:
-what do the lungs metabolize
- Histamine production
- converts angiostensin 1–> angiostenstin 2 (vasoconstrict)
- surfactant production
Thorax and Ribs function
rigid to protect & flexible to expand with inhalation
Lungs apex location
rises above clavicle
-risk for pneumothorax
Trachea anatomy
- anterior view
- posterior view
1) cartilage rings
2) smooth muscle
Conducting airways functions
- passageway to respiratory regions of lung
- NO AIR EXCHANGE
- hinders foreign material into gas exchange
respiratory airways
- type I epithelial cells
- 90% of space
- role in GAS EXHANGE
respiratory airways
-type II epithelial cells
produce, store, and secrete surfactant (reduces surface tension)
mechanics of breathing:
-what does 80% of WOB
diaphragm
mechanics of breathing:
-what muscles aid in WOB
- intercostal
- abdominal
- accessory muscles
Mechanics of breathing:
-where does the medulla send impulses to?
-the diaphragm via the phrenic nerve
Mechanics of breathing:
- where is the phrenic nerve located in the body?
- why is this important to know?
- C3-C5
- trauma to these areas cause severe respiratory problems
Mechanics of breathing:
-Compliance def.
the lungs ability to expand and ease of lung inflation
the more compliant, easier to bring air in
Mechanics of breathing:
- compliance in ARDS pts
decreased compliance
Mechanics of breathing:
-compliance in COPD pts
Increased compliance BUT cannot let air back out
-barrel chested (decr. elastic recoil)
How does the body prevent lungs from collapsing?
INTRAPLEURAL pressure found in the pleural space between the lungs is a negative pressure that acts as a vaccum
What happens if interapleural pressure and external (outside) pressure are equal?
pneumothorax
Physical law that describes how alveoli stay open?
LePlace’s law
What part of the body creates the negative pressure in the intrapleural space?
the lymphatic system
Mechanics of breathing:
- alveolar pressure during inspiration
the diaphragm pulls the lungs down creating NEGATIVE Pressure
Mechanics of breathing:
- alveolar pressure during expiration
POSITIVE pressure
atelectasis
complete or partial collapse of lungs
total lung volume
5500-6000 ml
Tidal volume
amount of air inhaled and exhaled with each breath
Inspiratory reserve volume
volume of air that can be inspired beyond tidal volume
Expiratory reserve volume
volume of air that can be expired by force after end of tidal expiration
residual volume
volume of air remaining in the lungs after a forceful expiration
Functional residual capacity (FRC)
air reserve (1000 ml)
why is intake of O2 important
- for metabolism
- to remove CO2
External respiration
gas exchange in alveolar-capillary membrane in the lungs
Internal respiration
diffusion of gases in and out of the cells at the tissue level
Diffusion
O2 and CO2 move from high concentration to low concentration
which is more diffusible in plasma? CO2 or O2
CO2
- O2 needs the help of hgb
Ventilation (V) & Perfusion (Q) should be what ratio at capillary membrane
equally matched- 1:1
V/Q
-shunt
perfusion (Q) in excess of ventilation (V)
- V
what dz causes shunts
- pneumonia
- mucus plug
- bad airflow but good blood flow
V/Q
-dead space
ventilation in excess of perfusion
- V>Q
- this is a HIGH ratio
what dz causes dead space
cardiogenic shock
* good airflow but bad blood flow
Two methods of oxygen transport
1) dissolved in plasma (PaO2)
2) chemically bound to hgb (SaO2)
Oxyhemoglobin Dissociation Curve
relationship between dissolved oxygen and hgb-bound oxygen
CRITICAL ZONE of oxy-hgb dissociation curve
when PO2
Oxy-Hgb Dissociation Curve:
- strength of bond in lungs
strong bond so that hgb can pick up O2 more easily in the lungs
Oxy-Hgb Dissociation Curve:
- strength of bond in tissues
weak bond so that hgb will let go of O2 and allow it to diffuse into the tissue
Oxy-Hgb Dissociation Curve:
-association between O2 saturation levels and P02 levels
after 80% O2 saturation, the P02 levels begin to fall below the critical zone
-this is why it is important to keep O2 sats >90%
Oxy-Hgb Dissociation Curve:
- what causes a shift to the LEFT
- High pH
- low PCO2
- low temp
- ALKALOSIS
Oxy-Hgb Dissociation Curve:
- what causes a shift to the RIGHT
- Low pH
- High PCO2
- high temp
- ACIDOSIS
Oxy-Hgb Dissociation Curve:
- Shift to the left patho
higher O2 saturation for any PaO2 & INCREASED hgb affinity
Oxy-Hgb Dissociation Curve:
-shift to the right patho
lower O2 saturation for any PaO2 and DECREASED hgb affinity
Control of breathing:
-what do the Pons & Medulla control ?
-AUTOMATIC ventilation
Control of breathing:
- what does the Cerebral cortex control?
VOLUNTARY ventilation
Central Chemoreceptors:
- where are they located
ventral surface of the medulla
Central Chemoreceptors:
-what do they react to?
changes in H+ ion concentration and directly driven by PaCO2
Central chemoreceptors:
- what happens when H+ ions increase
Ventilation increases
Central chemoreceptors:
- what happens when H+ ions decrease
Ventilation decreases
Central chemoreceptors:
-What is the most potent stimulus for breathing?
CO2
How does CO2 cross the BBB?
conversion of CO2 with H+ allows it to cross
where are peripheral cehmoreceptors located?
above and below the aortic arch
1) CENTRAL: what drives breathing?
2) PERIPHERAL: what drives breathing?
1) CO2
2) low O2
Why is it bad to give a COPD patient high levels of O2?
Their body is used to high levels of CO2. the low levels of O2 are the only mechanism that drives them to breath
* if high O2 is given to them, it may depress their breathing mechanisms
Hypoxemia
inadequate levels of oxygen in the blood
normal PaO2 levels in adults younger than 60
80-`100
normal PaO2 levels in adults older than 60
80 - # of years over 60 =
- age 66
80-6= 74 PaO2 ok!
Causes of hypoxemia
- hypoventilation
- Shunt (unventilated): blood reaches but no air
- ventilation/perfusion inequalities: underventilation most common cause
causes of hypoxia
- low O2 in tissues
- hypoxemia
- abnormal hgb
- low CO
- Low BP
- toxic substances
Body systems response to hypoxia
- tachycardia
- tachypnea, SOB
- decr. U.O : vasoconstrict
- restless, confusion
- ABGs
Hypoxic pulmonary vasoconstriction (HPV)
when there is low O2 in the lungs, re-routes blood to adequate oxygenated alveoli to reduce the shunt
S/S of ACUTE hypoxia
- pulmonary edema
- Cor pulmonale: R heart failure d/t pulmonary HTN
- COPD only cure is O2
Complications of oxygen therapy
- dehydration and cracking of mucosa
* use humidified air
Oxygen toxicity
breathing >50% for more than 24 hours causes severe gas exchange impairment with cough, dyspnea, and chest pain
how many liters of air given via Nasal Canula
1-6 liters
FiO2's: RA NC 1 L 2L 3L 4L 5L 6L
.21 .24 .28 .32 .36 .40 .44
simple oxygen mask
- components
- liters of air
- covers mouth a nose
- vents for exhale
- 5-8 L @ 40-60%
non-rebreathing mask
short term therapy for acutely ill
- 90-100 FiO2
- valves open for inhalation and close exhalation
- pt can only inhale fresh O2
high flow devices
- the O2 amount remains constant despite changes in ventilatory volume of the patient
- filters out the upper airway & fills it with O2
Normal values:
pH
7.35-745
PaCO2
35-45
HCO3
22-26
PaO2
80-100
SaO2
> 90
How are VOLATILE acids excreted?
as a gas
How are NON-VOLATILE acids excreted?
by the kidneys
-ex) lactic acid/keto acids
Regulation of Plasma pH:
-chemical buffers
- carbonic acid/bicard system: kidneys
- phosphate system
- proteinate system-most abundant b.c proteins in body
- responds in seconds
Regulation of Plasma pH:
- respiratory regulation
thru PaCO2 manipulation
*takes minutes
Regulation of Plasma pH:
-renal regulation
thru HCO3 elimination or conservation
*takes hours or days
Respiratory Alkalosis
- cause
- compensation
- Low PCO2
- d.t hyperventilation
- kidneys will excrete bicarb and keep H+
Metabolic Alkalosis
- cause
- compensation
- High HCO3
- d.t vomiting, diarrhea, NG suction, decr ventilation
- kidneys keep H+ and excrete bicarb
Respiratory Acidosis
- cause
- compensation
- High PCO2
- hypoventilation, mucus plug, obstruction
- kidneys excrete H+ and retain bicrarb
Metabolic Acidosis
- cause
- cpmpenstation
- Low HCO3
- d.t diarrhea, diabetic ketoacidosis, sepsis, low BP
- CO2 eliminated, kidneys excrete H+ and retain bicarb
S/S metabolic acidosis
pain, restless, chest pain, palpapitations, ALOC
-coma, low BP, tachycardia
Treatment of Metabolic acidosis
- fluids
- insulin
- dialysis
- vasopressors
- IV BICARB NOT A CURE
Potassium effect:
1) Acidosis
2) Alkalosis
1) hyperkalemia
2) hypolkalemia
Anion gap
difference between unmeasured cations and unmeasured anions
Anion Gap formula
Na- (Cl+Bicarb) = 8-16 mEq/L
what does an anion gap show?
severity of METABOLIC ACIDOSIS
anion gap >16 means?
renal failure or DKA
anion gap normal with acidosis means?
diarrhea
