O2 Transport Flashcards
Define Cooperative Binding
Hb affinity for O2 increases as its saturation increases
what alters PO2?
pH
temperature change
PCO2
2,3 DPG
what shift of the curve increases O2 unloading?
right shift (bohr effect)
what shift of the curve decreases O2 unloading?
Left
why is there a big drop in pressure as O2 enters the body
O2 gets diluted because of the exchange of O2 coming in and out of body
Blood perfusing the lungs is….
gravity dependent
bases are better perfused than apices
explain starling effect
amount of blood returned to the heart (preload) determines the amount ejected
what are some threats to O2 transport in regards to control of breathing?
altered CNS afferent Input
impaired efferent pathways
pharmacological and substance-abuse depression
what are some threats to O2 transport in regards to airways?
aspiration
obstruction secondary to airway edema, bronchospasm or mucus
inhaled foreign bodies
what are some threats to O2 transport in regards to airways ?
ineffective breathing pattern
ineffective airway clearance
chest wall abnormalities
impaired lung fluid balance and acute lung injury
what are some threats to O2 transport in regards to blood?
bleeding abnormalities low hematocrit secondary to GI bleed anemia thrombocytopenia disseminated intravascular coagulation thromboemboli
what are some threats to O2 transport in regards to gas exchange?
intrapulmonary shunt pulmonary edema V/Q mismatch diffusion defects alveolar collapse atelectasis body position
what are some threats to O2 transport in regards to respiratory muscles?
weakness fatigue neuromuscular disease upper abdominal surgery intestinal obstruction
what are some threats to O2 transport in regards to heart?
decreased venous return and CO conduction defects mechanical defects abnormal distension and myocardial wall compliance abnormal afterload
what are some threats to O2 transport in regards to systemic Hemodynamics?
blood pressure
volume deficit
volume excess
what are some threats to O2 transport in regards to tissue perfusion ?
impaired CO
atherosclerosis
thromboembolism
low O2 content in the blood
does the respiratory system limit exercise?
not in healthy untrained (over built)
in highly trained athletes it may limit because it does not adapt
how is EIAH characterized?
decrease in PaO2 and an increase in alveolar-to-arterial O2 difference
what could possibly cause EIAH?
inadequate hyper ventilatory compensation
ventilation/perfusion mismatching
arterio-venous shunting
pulmonary diffusion limitation
respiratory muscle fatigue and steal of skeletal muscle blood flow
define alveolar hypoventilation
alveolar ventilation below the rate metabolically required to maintain blood gases at normal levels
PaCo2>35mmhg
define extra pulmonary shut
deoxygenated blood returning from exercising muscles bypasses the lungs completely
define intrapulmonary shunt
deoxygenated blood that passes through the lungs but does not participate in gas exchange mixes with arterial blood and dilutes it
what are the 2 major determinants for alveolar capillary diffusion during exercise?
decreased transit time of RBC in the pulmonary capillary
increased distance for diffusion
what is the diffusion limitation functions of the Blood-gas barrier
must be able to perform pulmonary gas diffusion (thin walls)
but be able to withstand high capillary wall stresses with exercise so must be strong
