Respiratory Physiology Flashcards
Right Bronchial Tree
-more vertical/short, more chance of asperation pneumonia
Diffusion
-Co2 diffuses 4x faster than O2
-co2 sensitive to changes in ventilation
-o2 sensitive to changes in ventilation and diffusion
-need blood flow, air, close to capillary wall, sufficient o2
-takes 1/2 time RBC is in capillary to diffuse
CO2:
-Co2 (capillary) 46 + C02 (alveloi) 40 = co2 goes into alveoli
-Co2 (capillary) 40 + C02 (tissue) 46 = co2 goes into vein
O2:
-O2 (capillary) 40 + O2 (alveloi) 100 = O2 goes into capillary
-O2 (capillary) 100 + O2 (tissue) 40 = O2 goes into tissue
Hypercapnic
-increased Co2
-hypoventilation: increases Co2, lowers pH
>45 PaCo2
Hypoxemia
-decreased blood o2
<80% PaO2
Diaphram
-right sits higher
-tends to go upward with surgery and obesity
FRC
Functional residual capacity
-exhale and have residual air in lungs
Hypercompliant Lung
-stretches excessively without returning to normal during exhalation
-increased FRC, PaCo2, airway resistance
-Decreased PaO2, intrathoracic pressure
-COPD, Obstructive
Hypocompliant Lung
-does not expand or contrac correctly
-decreased VC and RV
-increased work and pressure
-restrictive, obesity, surgery
Tidal Volume
-500ml
-amount of air moved in and out in each breath
-decresed VC and RV
-increas
Inspiratory Reserve Volume
-3000ml
-max inspiration after normal inspiration
-decrease with restrictive
Expiratory Reserve Volume
-1100ml
-max one can expire after normal exhale
Residual Volume
-1200ml
-volume of air left in lungs after max exhale
-FRC-ERV=RV (cannot be measured)
Functional Residual Capacity
-volume of air in lungs after normal expiration
-RV + ERV
(cannot be measured)
-balances lung and chest wall forces
Inspiratory Capacity
-max volume one can inspire
-TV+ IRV
-decrease with restrictive
Vital Capacity
-max volume one can exchange in a respiratory cycle
-IRV+TV+ERV
-decrease with restrictive
Total Lung Capacity
-air in lungs during full inflation
-IRV+TV+ERV+RV
-RV+VC=TLC
(cannot be measured)
-decrease with restrictive, increase obstructive
FEV1
-forced expiratory volume in 1 sec
-80% of predicted/max
-based on age, gender, race, height
FVC
-forced vital capacity’-how much can you force out and in
FEV1/FVC
-percentage of vital capacity exhaled in 1 sec
->70% norm
Dynamic Airways Resistance
-increases as lung volumes dec
-forced exhalation increases resistance
Obstructive: longer exhale, more air out
Restrictive: faster exhale, less air out
Ventilation to Perfusion Ratio (V/Q)
-blood flow to alveoli must match ventilation or =hypoxemia
-changes with posture
-Norm: 0.8
Reduced: shunt, decreased ventilation to perfusion, blood shunted to other parts of the lung, vasoconstriction at arterioles to reduce BV, corrected with O2
Increased: dead space, increased ventilation to perfusion, vasodilation to increase BV, dead space
Control of Respiration
-increased CO2 increases ventilation and breathing drive
-Decreased O2 weakly stimulates (<60)
PaO2/Co2
-partial pressure of arterial O2 (80-100) /Co2 (35-45)
SaO2
-o2 sat of arterial hemoglobin (>90%)
HCO3-
Bicarbonate ion concentration (22-26)
pH
-<7.4 acidic
->7.5 alkaline
7.35-7.45
Hgb
-hemoglobin (12-16)
Hypocapnia
-Hyperventilation: raises pH, reduces Co2
-PaCo2 <35
Acid Base Regulation
-kidneys can extrete or retain HCO3 (slowly)
Increased Ecretion: low pH, metabolic acidosis
Decreased Extrcetion: high pH, metabolic alkalosis
-respiratory
Hyperventilation: raises pH, reduces Co2, respiratory alkalosis
Hypoventilation: increases Co2, lowers pH, respiratory acidosis
