Resp Flashcards
name 4 obstructive lung diseases
Asthma
COPD
Bronchiectasis
Bronchiolitis obliterans
name 7 restrictive lung diseases
Pulmonary fibrosis
Asbestosis
Sarcoidosis
Acute respiratory distress syndrome
Kyphoscoliosis e.g. ankylosing spondylitis
Neuromuscular disorders
Severe obesity
What does FEV represent
how much air you force out in one second
What does FVC represent
how much air you can exhale in a single breathe, kinda like air capacity of the lungs
how is FEV/FVC changed in restrictive disease
> 75 i.e. normal or increased
how is FEV/FVC changed in obstructive disease
<75
how is FEV changed in restrictive disease
reduced
how is FVC changed in restrictive disease
significantly reduced
how is FEV changed in obstructive disease
significantly reduced
how is FVC changed in obstructive disease
normal
3 systems involved in Granulomatosis with polyangiitis
ENT
resp
kidney
what is the most common organism isolated in patients with bronchiectasis?
Haemophilus influenzae (most common)
Pseudomonas aeruginosa
Klebsiella spp.
Streptococcus pneumoniae
what is the prognosis for sarcoidosis?
The majority of patients with sarcoidosis get better without treatment
Most only require symptomatic treatment in the form of nonsteroidal anti-inflammatory drugs
what is the diagnostic test for asthma in adults and children?
FeNO test and spirometry with reversibility
when should BiPAP be started in COPD [4]
COPD with respiratory acidosis pH 7.25-7.35
type II respiratory failure
cardiogenic pulmonary oedema unresponsive to CPAP
weaning from tracheal intubation
admission criteria for acute asthma [5]
- life threatening asthma
- previous near fatal asthma attack
- severe asthma that fails to respond to initial medical treatment
- severe asthma in a pregnant woman
- an attack occurring despite already using oral corticosteroid and presentation at night
which type of lung cancer is most common?
adenocarcinomas
seen in smokers
which lung cancer has the worst prognosis?
small cell lung cancer
which lung cancer is characterised by cavitating lesions?
squamous cell carinoma
which lung cancer can have Lambert-Eaton syndrome as a paraneoplastic feature?
how will this present?
small cell lung cancer
muscle weakness
how often should asthma treatment be stepped down?
How much should the steroid component be reduced?
every 3 months or so
When reducing the dose of inhaled steroids the BTS advise us to do this by 25-50% at a time.
which resp infection in common in alcoholics as well as diabetics ?
klebsiella
what is the colour of the sputum in klebsiella infection?
red currant jelly
what conditions is Klebsiella associated with?
lung abscess
empyema
skin feature of sarcoidosis [2]
lupus pernio
erythema nodosum
what is the first line treatment of stable COPD
SABA/SAMA
After first line treatment for COPD and the pt remains breathless, what is given to someone who has NO asthmatic features?
LABA + LAMA added
switch out the SAMA to SABA at this point
After first line treatment for COPD and the pt remains breathless, what is given to someone who has asthmatic features?
What if they are still breathless despite these additions?
LABA + ICS
offer triple therapy LABA + LAMA + ICS
examples of LABA
Serevent (salmeterol)
Foradil (formoterol)
Striverdi (olodaterol)
examples of SABA
Salbutamol - e.g. Ventolin.
Terbutaline - e.g. Bricanyl
examples of LAMA
tiotropium
aclidinium
umeclidinium
glycopyrrolate (also called glycopyrronium)
examples of SAMA [2]
ipratropium bromide
oxitropium bromide
when is treatment for sarcoidosis indicated?
what is a treatment option
involvement of organs like the eye or skin, heart, kidneys etc
steroids
patients with chest x-ray stage 2 or 3 disease who are symptomatic. Patients with asymptomatic and stable stage 2 or 3 disease who have only mildly abnormal lung function do not require treatment
hypercalcaemia
eye, heart or neuro involvement
OLD
what should be done in primary pneumothorax if the air rim is < 2cm and not SOB
discharge, consider aspiration
OLD
what should be done in primary pneumothorax if air rim is >2cm or SOB
chest drain
OLD
what should be done in secondary pneumothorax is air rim is <2 cm
if between 1-2cm attempt aspiration
OLD
what should be done in secondary pneumothorax if air rim is > 2cm and/or they are SOB
chest drain
OLD
what should be done in secondary pneumothorax if air rim <1 cm
oxygen and admit for monitoring for 24 hours
what intervention may be considered in recurrent/persistent pneumothorax?
video assisted thoracoscopic surgery (VATS)
causes of bihilar lymphadenopathy [5]
TB
sarcoidosis
lymphoma/malignancy
pneumoconiosis
fungi e.g. coccidiodomycoses, histoplasmosis
what is the criteria for discharge for an acute asthma attack
P- PEF >75%
S- stable on discharge medication for 12-24 hours
I- inhaler technique is checked
treatment of HACE
descent and dexamethasone
medication for the prevention of HACE
acetozolamide
treatment of HAPE [3]
descent
nifedipine, dexamethasone, acetazolamide, phosphodiesterase type V inhibitors*
oxygen if available
relative contraindications for chest drain [4]
INR>1.3
platelets <75
pulmonary bullae
pleural adhesions
what are some contraindications to lung cancer surgery [6]
- stage IIIb or IV (i.e. metastases present)
- FEV1 < 1.5 litres is considered a general cut-off point*
- malignant pleural effusion
- tumour near hilum
- vocal cord paralysis
- SVC obstruction
what is the home treatment for someone who is having recurrent exacerbations of COPD
home antibiotics and prednisolone
abx only to be taken when there is purulent sputum produced
before starting prophylactic azithromycin for COPD, what baseline tests must be done? [2]
- ECG for prolonged QT
- liver function
what is a complication of rapid pleural effusion drainage?
how can this be prevented?
re-expansion pulmonary oedema
request an urgent chest x-ray
avoided by clamping the drain regularly in the event of rapid fluid output i.e. drain output should not exceed 1L of fluid over a short period of time (less than 6 hours)
what systems can sarcoidosis effect?
eyes
skin
facial nerve
parotid
this is a multi system disease
what guides the use of abx in acute bronchitis
CRP
20-100 –> delayed abx
>100 –> immediate abx
difference between acute bronchitis and pneumonia [3]
- normal X-ray
- no sputum sometimes
- sore throat
treatment of acute bronchitis
doxycycline for 5 days
CI: children and pregnancy
what are the paraneoplastic syndromes of small cell lung cancer
Cushing’s syndrome and SIADH
what are the paraneoplastic syndromes of squamous cell lung cancers
PTHrp and HPOA
Acute asthma escalation:
1.
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2.
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3.
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4.
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5.
6. Aminophylline/ IV salbutamol
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamolAcute asthma escalation:
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6.
Acute asthma escalation:
1. Oxygen
2. Salbutamol nebulisers
3. Ipratropium bromide nebulisers
4. Hydrocortisone IV OR Oral Prednisolone
5. Magnesium Sulfate IV
6. Aminophylline/ IV salbutamol
two vaccines offered in COPD patients
Annual influenza + one-off pneumococcal
4 features of Kartagner’s syndrome
- dextrocardia or complete situs inversus
- bronchiectasis
- recurrent sinusitis
- subfertility (secondary to diminished sperm motility and defective ciliary action in the fallopian tubes)
who is LTOT offered to
LTOT should be offered to patients with a pO2 of < 7.3 kPa or to those with a pO2 of 7.3 - 8 kPa and one of the following:
secondary polycythaemia
nocturnal hypoxaemia
peripheral oedema
pulmonary hypertension
After smoking cessation, long-term oxygen therapy (LTOT) is one of the few interventions that has been shown to improve survival in COPD.
what are considered high risk characteristics in someone with symptomatic pneumothorax needing chest drain [6]
haemodynamic compromise (suggesting a tension pneumothorax)
significant hypoxia
bilateral pneumothorax
underlying lung disease
≥ 50 years of age with significant smoking history
haemothorax
- SABA
- SABA + ICS
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
7.
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS+ LABA + (LTRA)
- SABA +/- LTRA + MART
- SABA +/- LTRA + medium-dose ICS MART
- SABA +/- LTRA + high-dose ICS/LAMA/theophylline
management for lung abscess not responding to IV abx
CT guided percutaneous drainage
protein in exudative effusion
> 30 g/L
protein in transudative effusion
<30 g/L
management of pleural effusion
diagnostic aspiration followed by chest drain
Lights criteria for exudative effusion
pleural fluid protein divided by serum protein >0.5
pleural fluid LDH divided by serum LDH >0.6
pleural fluid LDH more than two-thirds the upper limits of normal serum LDH
causes of upper zone fibrosis
Coal workers’ pneumoconiosis
Histiocytosis X,
Ankylosing Spondylitis,
Radiation,
TB
Sarcoidosis/Silicosis
medicines that cause lower zone fibrosis [6]
busulfan
bleomycin lung toxicity
nitrofurantoin
hydralazine
methotrexate
amiodarone
first line treatment for HAP
co-amoxiclav or doxycycline
if severe: Tazocin
percussion note in pneumonia
dull
percussion note in pleural effusion
stony dull
percussion note in pneumothorax
hyper-resonant
vocal fremitus in pneumonia
increased
vocal fremitus in pleural effusion
reduced
vocal fremitus in pneumothorax
reduced
causes of tracheal deviation towards affected side [2]
pneumothorax/lung collapse
pneumonectomy
where are bronchial breath sounds heard
over the trachea
where are vesicular breath sounds heard
best heard posterior lung bases
what does Veil sign indicate
left UPPER lobe collapse e.g. in malignancy
what does Sail sign indicate
left LOWER lobe collapse
what does Thymus sail sign indicate
normal, seen in neonatal CXR
symptoms and signs of lung abscess [4]
- foul smelling sputum
- occurs over weeks
- systemic: night sweats
- dull percussion
investigation of lung abscess [2]
chest x-ray
sputum and blood culture
what do lung abscesses occur secondary to most of the time
aspiration pneumonia
typically polymicrobial
monomicrobial causes include:
Staphylococcus aureus
Klebsiella pneumonia
Pseudomonas aeruginosa
DVT prophylaxis in air travel
if medium- high risk–> anti embolism stockings
NO role for aspirin
gold standard for diagnosis of COPD
spirometry
prophylactic treatment of COPD exacerbation
azithromycin
FEV1% in mild COPD
> 80%
FEV1% in moderate COPD
50-79%
FEV1% in severe COPD
30-49%
FEV1% in very severe COPD
<30%
FEV1/FVC in asthma
< 70% i.e. obstructive
FeNO in asthma diagnosis
> =40 ppb
BDR in asthma
> =12% in variability and >200ml increase in volume after SABA administration
peak flow variability in asthma
> 20%
which severities of asthma need admission
acute severe with no response
life threatening and near fatal
what happens to the ABG in near fatal asthma
raised pCO2
when should a patient be reviewed after discharge due to asthma attack
48 hours
PEF in moderate asthma
50-75%
PEF in acute severe asthma
33-50%
PEF in life threatening asthma
<33%
treatment of pneumonia due to legionella
erythromycin/clarithromycin + rifampicin
treatment of pneumonia due to staph
flucloxacillin
which organism tends to cause pneumonia in those with pre-existing lung disease
H. influenzae
which organism causes cavitating lesions on CXR and is associated with a recent viral infection
staph aureus
C-
U- Urea >7mmol/L
R- RR >30
B- BP <90 sys <60 dia
65 yo +
C- Confusion
U- Urea >7mmol/L
R- RR >30
B- BP <90 sys <60 dia
65 yo +
C- Confusion
U-
R- RR >30
B- BP <90 sys <60 dia
65 yo +
C- Confusion
U- Urea >7mmol/L
R- RR >30
B- BP <90 sys <60 dia
65 yo +
C- Confusion
U- Urea >7mmol/L
R-
B- BP <90 sys <60 dia
65 yo +
C- Confusion
U- Urea >7mmol/L
R- RR >30
B- BP <90 sys <60 dia
65 yo +
C- Confusion
U- Urea >7mmol/L
R- RR >30
B-
65 yo +
C- Confusion
U- Urea >7mmol/L
R- RR >30
B- BP <90 sys <60 dia
65 yo +
C- Confusion
U- Urea >7mmol/L
R- RR >30
B- BP <90 sys <60 dia
age?
C- Confusion
U- Urea >7mmol/L
R- RR >30
B- BP <90 sys <60 dia
65 yo +
which organism cause HAP within 48 hours to 4 days usually in hospital
strep pneumo
which organism causes HAP beyond 4 days of hospital admission
enterobacteria mainly
staph aureus
pseudomonas
treatment of severe HAP
piptazobactam (tazocin)
treatment of Klebsiella pneumonia
cephalosporin
treatment of pseudomonas pneumonia
piptazobactam
gold standard for diagnosis of TB
sputum culture
takes 1-3 w
NAAT will take 24-48 hours
which test for TB does NOT cross react with BCG vaccine
IGRA
3 side effects of rifampicin
1) orange secretions
2) raised ALT/AST
3) enzyme inducer
3 side effects of isoniazid
1) hepatotoxic
2) peripheral neuropathy (therefore give pyridoxine)
3) enzyme inhibitor
side effect of pyrazinamide
hepatoxicity
side effect of ethambutol
visual disturbance:optic neuritis
how long are each of the TB treatment drugs given for
describe the regime
R- 6m
I- 6m
P- 2m
E- 2m
RIPE for 2 months followed by R and I for a further 4 months
treatment of MDR TB
rifampicin and isoniazid
treatment of XDR TB
rifampicin, isoniazid, fluoroquinolone and injectable
key investigations in pleural effusion
CXR, USS guided pleural aspiration with chest drain
EBUS
investigation for hypersensitivity pneumonitis
bronchoalveolar lavage shows increased cellularity
Conditions that cause lower zone lung fibrosis [3]
asbestosis
idiopathic pulmonary fibrosis
rheum: RA, SLE, Sjorgrens, CREST
lung sounds in idiopathy pulmonary fibrosis
fine end-inspiratory creps
TCLO in idiopathic pulmonary fibrosis
low
spirometry image in IPF
restrictive
diagnostic imaging for IPF
HR-CT
management of IPF
cons: physio; rehab; stop smoking
med: LTOT, anti-tussives
treatment of ABPA
PO glucocorticoids
diagnostic test for cystic fibrosis
chloride sweat test >60
1st line mucolytic therapy for cystic fibrosis
dornase alfa
prophylactic abx in cystic fibrosis
flucloxacillin and azithromycin
nutritional management of cystic fibrosis [3]
high calorie
high fat
fat soluble vitamins
what percentage of lung cancers are non-small and small
85% non small
15% small
which lung cancers affect central airways
small cell and squamous cell
which lung cancers affects peripheral airways
adenocarcinoma and large cell carcinoma
key investigations for lung cancer [3]
CXR
CT, PET for staging
bronchoscopy + EBUS with biopsy
which drugs reduce the risk of COPD exacerbations in patients with severe COPD and a history of frequent COPD exacerbations
Oral PDE-4 inhibitors such as roflumilast
how does the chest drain swing during inspiration and expiration when treating pneumothorax
Rises in inspiration, falls in expiration
what is Peabody sign
found in patients with a deep vein thrombosis (DVT) and a positive test indicated by calf muscle spasm occurring on elevation and foot extension of the affected leg
what type of shock does a tension pneumothorax cause
obstructive
how are pneumothorax patients managed according to 2023 guidelines
depending on whether they are symptomatic or not, regardless of pneumothorax size
the BTS define minimal symptoms as ‘no significant pain or breathlessness and no physiological compromise’
if minimal symptoms: conservative care, regardless of pneumothorax siz
if symptomatic: assess for high-risk characteristics
how do you treat a symptomatic pneumothorax with no high risk characteristics if it is safe to intervene
conservative care
ambulatory device
needle aspiration
how should patients with primary and secondary pneumothorax be monitored (conservative care)
patients with a primary spontaneous pneumothorax that is managed conservatively should be reviewed every 2-4 days as an outpatient
patients with a secondary spontaneous pneumothorax that is managed conservatively should be monitored as an inpatient
if stable, follow-up in the outpatients department in 2-4 weeks
what is used in ambulatory care of pneumothorax
an example of an ambulatory device is the Rocket® Pleural Vent™
it includes an 8FG catheter mounted on an 18G needle and a pigtail catheter to minimize the risk of occlusion
ambulatory devices typically have a one-way valve and vent to prevent air and fluid return to the pleural space while allowing for controlled escape of air and drainage of fluid
many devices also have an indication diaphragm that signals when the catheter tip enters the pleural space and continues to fluctuate with respiration, aiding in the assessment of pneumothorax resolution
when may patients fly after a pneumothorax
may travel 2 weeks after successful drainage if there is no residual air.
causes of transudative pleural effusion
heart failure (most common transudate cause)
hypoalbuminaemia
liver disease
nephrotic syndrome
malabsorption
hypothyroidism
Meigs’ syndrome
causes of exudative pleural effusion
infection
pneumonia (most common exudate cause),
tuberculosis
subphrenic abscess
connective tissue disease
rheumatoid arthritis
systemic lupus erythematosus
neoplasia
lung cancer
mesothelioma
metastases
pancreatitis
pulmonary embolism
Dressler’s syndrome
yellow nail syndrome
2 history features in allergic bronchopulmonary
key investigations
history of bronchiectasis and eosinophilia.
eosinophilia
flitting CXR changes
positive radioallergosorbent (RAST) test to Aspergillus
positive IgG precipitins (not as positive as in aspergilloma)
raised IgE
treatment of allergic bronchopulmonary aspergillosis
oral glucocorticoids
itraconazole 2nd line
lung features of Alpha 1 antitrypsin def
panacinar emphysema of the lower lobes
investigations for Alpha 1 antitrypsin def
A1AT concentrations
spirometry: obstructive picture
management of Alpha 1 antitrypsin def
no smoking
supportive: bronchodilators, physiotherapy
intravenous alpha1-antitrypsin protein concentrates
surgery: lung volume reduction surgery, lung transplantation
management of atelectasis
positioning the patient upright
chest physiotherapy: breathing exercises
respiratory causes of clubbing
lung cancer
pyogenic conditions: cystic fibrosis, bronchiectasis, abscess, empyema
tuberculosis
asbestosis, mesothelioma
fibrosing alveolitis
causes of respiratory acidosis
COPD
decompensation in other respiratory conditions e.g. life-threatening asthma / pulmonary oedema
neuromuscular disease
obesity hypoventilation syndrome
sedative drugs: benzodiazepines, opiate overdose
causes of respiratory alkalosis
anxiety leading to hyperventilation
pulmonary embolism
salicylate poisoning*
CNS disorders: stroke, subarachnoid haemorrhage, encephalitis
altitude
pregnancy
Predisposing factors to OSA
consequences
obesity
macroglossia: acromegaly, hypothyroidism, amyloidosis
large tonsils
Marfan’s syndrome
daytime somnolence
compensated respiratory acidosis
hypertension
management of OSA
weight loss
continuous positive airway pressure (CPAP) is first line for moderate or severe OSAHS
intra-oral devices (e.g. mandibular advancement) may be used if CPAP is not tolerated or for patients with mild OSAHS where there is no daytime sleepiness
the DVLA should be informed if OSAHS is causing excessive daytime sleepiness
features of Granulomatosis with polyangitis
Upper respiratory tract: epistaxis, sinusitis, nasal crusting
Lower respiratory tract: dyspnoea, haemoptysis
Glomerulonephritis
Saddle-shape nose deformity
extra heart sound in pulmonary oedema
S3
what can be offered for smoking cessation [3]
nicotine replacement therapy (NRT), varenicline or bupropion
MoA of vareniciline
nicotinic receptor partial agonist
contraindicated in pregnancy and breast feeding
MoA of bupriopion
CI?
norepinephrine and dopamine reuptake inhibitor, and nicotinic antagonist
CI: epilepsy, pregnancy and breast feeding
most common cause of occupational asthma
isocyanates
include spray painting and foam moulding using adhesive
what is total gas transfer (TLCO)
overall measure of gas transfer for the lungs from the alveoli into the capillaries and reflects how much oxygen is taken up into the red cells.
what is transfer coefficient KCO
TLCO divided by the alveolar volume, which makes it a measure of how efficient gas exchange is in relation to the alveolar-capillary surface to volume ratio.
causes of raised TLCO
asthma
pulmonary haemorrhage (e.g. granulomatosis with polyangiitis, Goodpasture’s)
left-to-right cardiac shunts
polycythaemia
hyperkinetic states
male gender, exercise
causes of lower TLCO
pulmonary fibrosis
pneumonia
pulmonary emboli
pulmonary oedema
emphysema
anaemia
low cardiac output
how does KCO change with age, What conditions can increase it
KCO increases with age
pneumonectomy/lobectomy
scoliosis/kyphosis
neuromuscular weakness
ankylosis of costovertebral joints e.g. ankylosing spondylitis
investigation for OSA
sleep studies (polysomnography)
Epworth Sleepiness Scale - questionnaire completed by patient +/- partner
Multiple Sleep Latency Test (MSLT) - measures the time to fall asleep in a dark room (using EEG criteria)
when should LTOT be started
2 measurement so pO2 < 7.3