12.12.12 Respiratory lectures
Less radiation than CTPA
Takes 2-3 days to request + do
Only gives high, intermediate and low probabilities
Can only do if CXR is normal
Can do just the V bit if pregnant/radiation concern
RV strain pattern
Right axis deviation
To look for cardiac signs of PE
Reduced output, RV strain
Via central line
Do on HDU
BTS don't recommend D-dimer if there is a high clinical suspicion of PE
Look for a DVT
If there's evidence of DVT on ultrasound and clinical signs of PE, start treating
3 - 6 months of anticoagulation
Target INR 2-3
Consider thrombophilia screen (off warfarin) if:
Less than 50
Indications for alteplase:
Engorged neck veins
Give 50mg bolus of alteplase
Must give 60 mins of CPR afterwards
PE risk factors
Risk factors for venous thromboembolism
Major risk factors: relative risk of 5-20
Major abdominal/pelvic surgery
or hip/knee replacement
(risk lower if prophylaxis used).
Postoperative intensive care.
Lower limb problems:
Varicose veins - previous
varicose vein surgery;
superficial thrombophlebitis; varicose veins per se are not a risk factor.
Previous proven VTE:
Intravenous (IV) drug use
(could be major or
minor risk factor:
no data on relative risk).
Spinal cord injury.
Central venous lines.
Minor risk factors: relative risk of 2-4
Congenital heart disease.
Congestive cardiac failure.
Pregnancy (but see major risk factors for late pregnancy and puerperium).
Combined oral contraceptive.
Hormone replacement therapy.
Consider this in cases of PE aged <40 years, recurrent VTE or positive family history.
Paroxysmal nocturnal haemoglobinuria.
Chronic obstructive pumonary disease
Long-distance sedentary travel.
Other chronic diseases: inflammatory bowel disease, Behçet's disease.
If not expectorating
Urinary antigens for some organisms
Metronidazole vs Anaerobes
Multiseptated effusions are hard to drain
Smoking (12% of smokers!)
Underlying lung pathology
2cm space between chest wall and pleural line, at the level of the hilum
Gets into the pleural space, and is reabsorbed quicker than nitrogen
Check CT for secondary pathology, e.g. blebs that might have popped
54% risk within 4 years
Esp. if still smoking
Chest drain management
If still bubbling, can use 5 cm water pressure to suck air out
Rapidly acting beta2 agonist; Also long-acting
Measures upper/large airway function
=> Good for asthma, but not for COPD (affects medium + small airways)
Do a blood gas in acute asthma only if sats < 92%
Antagonises calcium release in smooth muscle
Can only use once
Causes muscle weakness / resp. failure
Xanthine derivative (c.f. tea when you have a cold)
Phosphodiesterase inhibitor and adenosine receptor antagonist
Some central mechanisms too
LTRAs have no proven benefit in acute asthma
Role for heliox?
No role for antibiotics in acute asthma - Exacerbation is usually viral
Asthma discharge criteria
Diurnal peak flow variation <25%
< 4 hourly nebs
Back on usual meds
Follow-up plan in place
With GP within 48hrs
Hospital within a month
Follow up for a year
Pathophysiology - Due to toxious stimuli
Elastin/connective tissue defect
Loss of elastic recoil
Mucous plugging + airway defects
Admit to ICU if acidotic with pH <7.25
For antibiotic use in acute exacerbation of COPD
Need 2 out of 3 of:
Increased sputum volume
Increased sputum purulence
Resp. failure is pO2 < 8 kPa
Must use LMWH to anticoagulate if pregnant, not warfarin
CTPA => 14% increased risk of breast cancer
Systemic inflammation => Cachexia
Doxapram = Centrally acting respiratory stimulant
No use in COPD
Used in drug overdose etc
pH kills patients, not CO2