Volatiles Flashcards
What oxidative metabolites does hyperoxia cause
Hydrogen peroxide
Free radicals such as superoxide
Hydroxyl radicals
WHat is the process of damage in hyperoxia?
Endothelial neutrophil and macrophage recruitment, release of inflammatory mediators
-REductin in surfactant production, evolution of interstitial oedema and ARDS
-Impairment of diffusion and gas exchange, hypoxia and pulmonary fibrosis at 1 week
WHat are the avg times before normobaric oxygen therapy causes detectable changes in pulmonary function?
FiO2/time
1- 12 hours
0.8- 24 hours
0.6 36 hours
WHat can accelerate pathological changes from oxygen
Critical illness
Symptoms of oxygen toxicity?
Retrosternal discomfort, cough. dyspnoea, carinal irritation, ards
What can cause changes at ‘normal’ concentrations of inspired oxygen?
Mitomycin C
Bleomycin
What conditions can neonatal hypoxia cause/contribute to?
Retinopathy of prematurtiy
NEX
Bronchopulmonary dysplasia
ICH
WHat is the bert effect?
Describes the effect of hyperoxia on the CNS under hyperbaraic conditions
at 2 atm- paraesthesia, nausea, twitching,oflactory + gustatory disturbances
-ABove 2-3 atm, convulsions occur
WHat is the smith effect?
Similar but accelerated changes to the lungs in hyperbaric oxygen toxicity
At 2 atm, VC changes can occur in as little as 4 hours
What effects alveolar fractional concentration?
Alveolar ventilation, Fi and FRC> increased FA will be acheived by increasing alveolar ventilation and/or Fi
Why does a high FRC reduce the rate of rise of alveolar fractional concentration?
Provides a large resevoir, prolonging filling timeH
How is alveolar fractional concentration linked to onset/equilibrium time
Driving force for diffusion into the bloo so higer concs reduce the onset time
