B6- Examining Respiratory System II Flashcards
What is pulse oximeter put on finger estimating
Estimates saturation of peripheral oxygen (Spo2). (Estimation of aretial Sao2)
How does it use absorbance
Uses difference in absorbance of infrared and red light by deoxygenated venous and oxygenated arterial to determine Spo2
What saturation indicates normal oxygen saturation using pulse oximetry
90%
What would affect the readings
Circulation to hand, nailvarnish, co poisoning, skin pigmentstion affects readings
What is better accurate measure
Arterial blood gas analysis abga
Does pulse oxometry indicate levels of co and co2
No whcih is an issue as significant
What would happen if no hb eg in antarctic ice fish
Lack of aaturation of oxygen
Does blood have more cpascity to carty o2 or co2
Co2 but much lower at around 40 compared to 100mmhg because tight regulatio
What is added to blood in agba and why
Heparin to dtop coagulation of blood sample
How is blood drawn
Aneribically to block changes in gases
What does agba measure
Ph, pao2,paco2, hco3 bicarbonate levels all in arrterial blood
What should ph be and what would cause increqse or decrease leading to cell death
7.35-45. If lower emans more co2 if higher more hco (alkalosis)
What are normal paco2 from agba unless hypo/hypervent
35-50 mmhg
What do low levels or high lrvels of hco indicate
Low means metabolic issue
High means its a compensatort effect eg in chronic diseases
What is normal pao2 in agba
75-105mmhg (venous is 60)
What is an acid base and buffer
Acid is a proton donator
Base is proton acceptor
Buffer reversibly binds protons/h ions = resistance to ph change
How much co2 is dissolved in blood freely
10%
30% of co2 are in carbamino compounds with proteins. Give an example
Carbaminohaemogoblin (co2Hb)
What happens to the rest of co2 (60%)
Teacts with water eg in rbc via carbonic anhydrase and produces carbonic acid which is dissociated to h and hco
What protein acts as a buffer by binding H through 38 hidtidine residues
Haemoglobin
What type of haemoglobin bunds H only
Reduced (oxyfen would displace it)
Other than the hb buffer. What else allows buffering in acid response/coping wirh co2
H+ can be removed by distal tubule cells in kidney and hco can be released
Why is co2 exchnage out of lungs important
Reduces lecels of carbonic acid restoring ph
Which arrucle discusses ph refulstion in co2 increase by chemorecetors
Nattie 1999
What did nattie 1999 find
Peripheral chemo csrotid body glomus cels have a ph snesitice k channel which closes in reduced during metabolic acidosis causinf depolarisation and gkuramate release allowing hyperventilating
Which article discusses carrying of co2
Arthurs et al 2005
Why when carbonic acid dissociates to hco in rbc is hco removed and how (arhturs 2005)
Removed by cl exhcnage so cell doesnt rupture
What does co2 bind to to form carbamino compounds (arthurs)
The uncharged amino group on proteins eg haemoglobin
Which part of the 38 histidines acts as a base when hhb forms in reduced haemoglobin
Imidazole
What forms if H is increased too much eg due to haldene effect
Co2 whixh is rhen removed forn lungs
What does reducing co2 from lungs reduce
Hco and h lecels
How many ml/min of co2 is exhaled
200ml/min from lungs = cope with co2
What is acute tespiratory acidosis
Increased co2 (no change in hco)
This is due to hypoventilation or v/q mismatch.
What diseases xause this hypoventilation
Neuromuscular diseases, obstrcutivr diseases eg asthma or copd
What increases in chronic resp acidosis
Both co2 but compensatory effect causes also increased hco
Does chronic reap acidosis have same causes ie neuromusc, obstructive, v/q mismatch
Yes as hypovent causes increased co2 and so does v/q
Does eenal compensatory effect inly occur in chronic acidosis
Yes
What is respiratory alkalosis and give where it can occur
Increase in ph and low co2 due to hyperventilation ef during stress or in altitude
What can happen if respiratory alkalosis is prolonged
Renal compensation
Which articel discusses respiratort alkalosis
Alan et al 2020
What did alan et al 2020 say about renal comp in resp alkalosis
Found refuced hco reabsoprtion by distal and also refuced ammonihm which gathers if too kuch h is exceeted, meaning h is beint retained to stop alkalosis
How can diabetes cause mrtwbolic acidosis (not to do eith co2 levels)
Ketogenesis
How can renal failure cause metabolic scidosis
If too much hco is excreted
Which response occurs in metabolic scidosis (nattie 1999)
Rhe peripheral carotid reaponse of hyperventilation to reduce ph via co2
What 2 things is metabolic alkalosis caused by
Increased hco ef if ingested alkaline substance, or reduced H eg cia vomiting
Respiration evetnually compensates for metabolic alkalosis. How
Hypogentilstion to increase co2 and redcue ph
Ehcih artucle discusses alternstive increase of hco other than ingesting alkaline substajces
Emmett 2020
Which organ otrhet than kidney can increase hco snd how (emmett 2020)
Stomach increase hco via secretion of hcl to counteract hcl gastic acid
Which ion is needed to be reabsorbed at proximal tubule in order to traffic hco out via reabsoroption too causing m alaklosis (emmett 2020)
Na vis the na hco cotransporter
Which diseases/meds increqae na reabsorption therefore HCO reabsorption
Aldosterone
Or mineralocorticoid excess syndrome
How does resp alkalosis drcrease in co2 (hypervent) have effect on prrson eg at high altitude (alan 2020)
Seizures, dizziness rtc due to lsck of cerebral flow
How di you stand for radiology (taken at full inspiration)
Erect and anterooosterior
Loss of lung markings/loss of signal is caused by what if 1 or both lungs
If 1 lung means could be pneumothorax where air gets to pleura of a lung
If borh irs likely emphysema air increases
If there is hazy patches on 1 or both lyngs what is it
If 1 its usually infection
If both its likely fiboriss /ards/resitrcivie
Dense shadowing/whiteness on xray is callef what
Consolidation
What can cause consolidation
Fluid build up or collapse of lung
What can cause consolidwtion and collapsed lung
Obstruction eg food in trachea or carcinoma or mycus blocking oxygen in lung
What does no wherzing with asthma indicate
Collapsed lung
What happens to the outer tissue of lungs in consolidation other than fluid filled or collapsed
Can be hardened or thickened eg fibrosis
What 2 patterns of fibrosis haziness is rhete
Net like / reticular or nodular
What does honeycomb pattern in advanced fubrosis cause on xray
Circular translucencies where there is permanent loss of tissue
What is rhe opacification sround the tranlucent honeycomb
Deposits
Which scan gives better tissue scanning of finrosis patients
Ct scan
What is high attenuation eg seen in fubrosus
Loss of intesnitity heroygh medium due ti fluid, thickness of mass or tissue ie same as consolidation
What are ground glass opacities xaused by (opacification is shadowing)
Increased thickening of interstitium by interstitial diseases like fibrosis, or air sspace diseases
Caused by increwsed mucus, pus, ifnlammation, oedema, fibrosis in alvroli
What does loss of attenuation shadowing indicate
Loss of lung tossue = translucent
Other rhan honeycombinng whag kther examples of loe attentuation are there / transucency
Cysts
Bronchiectasis
Emphysema
What is traction bronchiectasis with low attentuation
Irreversible dilation due to fibrosis
What are nodules of opacitity/densitity indication of
Infections, dusts or metastases
Which scan indicates through a radioactivr drug can indicate activr cells eg metastatic cells
Pet scans
What is a pulmonary ct angiogram
Ehere a contrast dye is injected to cisualise the pulmonary arteries and indicate pulmonary embolisms
