quiz 1 Flashcards
DO2
what it is and equation
- oxygen delivery
2. arterial oxygen content * cardiac output
VO2
what it is and equation
- oxygen consumption
2. (arterial oxygen content - venous oxygen content)* cardiac output
OER
what it is and equation
- oxygen extraction ratio
2. oxygen consumption (VO2)/ oxygen delivery (DO2)
definition of O2 convection
movement of O2 from alveoli to tissue capillaries
definition of O2 diffusion
movement of O2 from capillaries to mitochondria
O2 convection is determined by: (3)
- [Hb]
- O2 saturation
- CO
O2 diffusion is determined by: (4)
- metabolic rate
- vascular resistance
- capillary recruitment
- tissue O2 consumption and extraction
at rest DO2 is __x times the metabolic demand in a healthy individual
4x
VO2 can increase up to __x fold in response to exercise in a healthy individual
20x
CO (def and equation)
- volume of blood being pumped out of L or R ventricle
2. stroke vol * heart rate
CO can increase up to __x fold in response to exercise demand in a healthy individual
5x
define preload
muscle fiber length of ventricle before systolic ejection
define afterload
resistance to the ejection of blood during ventricular systole
define O2 debt (2)
- recovery O2 consumption
2. difference btwn O2 demand and VO2
how does O2 demand change from rest to peak activity level?
increases
how is O2 demand altered in a patient at rest in health vs. illness
a sick patient has increased O2 demand due to increased work of breathing, work of the heart, pain, increased body temp or healing process
what is the difference between VO2 max and VO2 peak?
VO2 peak is the O2 consumption of an individual when performing max effort doing a specific exercise. VO2 max is the theoretical value of all systems working together maximally => more muscles working - VO2 peak gets closer to VO2 max
what is a good measure of anaerobic metabolism in a pt with multiorgan failure? why?
Serum lactates because tissue anaerobic metabolism and the development of lactic acidosis are associated with the critical level of VO2
why is it important to limit undue metabolic demand in a critically ill pt?
in a critically ill pt O2 is being used for basic metabolic needs and may not be able to be accessed by tissues that need it
what are 3 primary components in assessing the acute exercise response?
- establishing a baseline for pre-existing conditions
- determining the responses, both objective and (3) subjective during the onset, steady state phase, cool down and recovery
