Oxygen Transport Flashcards
What is Methemoglobin?
When Fe atoms are oxidized from the ferrous to ferric state so MetHgb cannot release O2.
What are some causes and signs of methemoglobin?
Caused by nitrite poisoning; blood appears brownish and patients skin looks blue/grey.
What level of reduced hemoglobin is required to produce cyanosis?
5gm/dL (50gm/L)
What is DO2?
The amount of oxygen delivered to peripheral tissue each minute.
What is DO2 controlled by?
Qt (cardiac output), Hb concentration, Hb saturation, and dissolved oxygen, in that order.
What are some factors that increase C(a-v)O2?
Decreased cardiac output, periods of increased oxygen consumption (exercise, seizures, shivering, hyperthermia).
What are some factors that decrease C(a-v)O2?
Increased cardiac output (decreased transit time), skeletal muscle relaxants (pavulon, curare), peripheral shunting, some poisons, hypothermia.
Define oxygen consumption (VO2)
The amount of oxygen absorbed across the lung in the process of pulmonary gas exchange (external respiration) is exactly equal tot he amount of oxygen consumed by peripheral tissue during metabolism (internal respiration).
What is the oxygen extraction ratio?
The amount of oxygen extracted by tissues divided by amount of oxygen delivered.
What is a normal oxygen extraction ratio?
0.25 or 25%
