Hypoxia Flashcards
What is hypoxia?
An oxygen deficency at tissue level, and if it persists you will see tisue necorsis
What is hypoxaemic or repsiratory hypoxia?
Poor oxygenation in lungs, low PO2 and low oxygen saturation
What is anaemic hypoxia?
Normal pO2 but insufficent Hb to carry O2 such as in the case of anemia and Co poisoning
What is stagnant or circulatory hypoxia?
Reduced delivery of O2 due to poor perfusion, could be global such as shock or local as in vascular disease
What is cytotoxic hypoxia?
The O2 delivery is adequate by the cells are iuable to use O2 such as in cyanide posioning
What level of O2 in the blood is considered to be hypoxia?
When the P2 saturationor os <90% or when the pO2 is 8kpa
What is type 1 respiratory failure?
When the pO2 of aterial blood low < 8KPa and the oxygen saturation <90% but the pCO2 os normal or low
What is type 2 respiratory failure?
The pO2 in aterial blood <8kPa, the lxygen saturation <90% and the pCP2 is high, above the normal range
What is vetilarotry failure and what kind of respiratory failure does it cause?
This causes type 2 respriatory failure and it is when you are unable to move sufficent ari in and out of the lung
What are the mechanisms that may cause type 1 respiratory failure
Poor diffusion across the alveolar membrane, and mismatching of ventitilation and perfusion
What are some of the key causes of ventiloatprt failure?
Mypoathy, MND. Severe obesity, kpyphsocilosis lung fibrosis and the late stages of COPD and a flail segment
What is a flail segment?
A segment os chest wall that is where multiple robs are fractured in two places and during inspiration the segment gets pulled inwards preveting adequate lung expanisopn
What are some of the acute effects of type 2 respiratory failure?
The pCO2 rises and the pO2 falls, the central chemroeceptros are stomualtes, and there is breathlessness where there is some compensation by the increase in ventilation rate but due to disease inable to completly correct defect, the high CO2 causes the respiratory acodpsis and the actuteq type 2 usually needs assisted ventilation
What are some of thie things that can cause difusion impairment across a membrane?
The thickness of the membrane may be increased due to lung firbsois and the avoalble surface area may be reduced due to empysema
Why does diffusion impariement cause type 1 repsiraptpry failure
The rate pf diffusion of oxygne is less than the rate of diffuson of carbon dioxode
