12.12.12 Respiratory lectures

PE

• • Risk factors

    • Smoking

    • Overweight

    • Cancer

  • VQ scan

    • 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

    • RBBB

    • Right axis deviation

    • S1Q3T3

  • TTE

    • To look for cardiac signs of PE

      • Reduced output, RV strain

  • Thrombolysis

    • Via central line

    • Do on HDU

  • BTS don't recommend D-dimer if there is a high clinical suspicion of PE

  • Immediate management

    • Treatment-dose heparin

    • Oxygen

    • IV fluids

    • Look for a DVT

      • If there's evidence of DVT on ultrasound and clinical signs of PE, start treating

  • Long-term management

    • 3 - 6 months of anticoagulation

      • Target INR 2-3

    • Consider thrombophilia screen (off warfarin) if:

      • Recurrent PE

      • Less than 50

      • Family Hx

  • Indications for alteplase:

    • Massive PE

      • Collapse/hypotension

      • Unexplained hypoxia

      • Engorged neck veins

      • Gallop rhythm

    • Give 50mg bolus of alteplase

    • Must give 60 mins of CPR afterwards

PE risk factors

Pneumonia

• • Bronchoscopy

    • If not expectorating

    • Lobar collapse

  • Urinary antigens for some organisms

  • HAP

    • Gram -ves

    • Pseudomonas

    • Anaerobes

  • Metronidazole vs Anaerobes

  • Multiseptated effusions are hard to drain

Pneumothorax

• • Types

    • Primary

    • Secondary

    • Iatrogenic

    • Traumatic

  • Clinical features

    • Tension

    • Open

    • Closed

  • Risk factors

    • Smoking (12% of smokers!)

    • Underlying lung pathology

    • Tall

    • Age >60

  • Small/Large cutoff:

    • 2cm space between chest wall and pleural line, at the level of the hilum

  • Give oxygen

    • Gets into the pleural space, and is reabsorbed quicker than nitrogen

  • Check CT for secondary pathology, e.g. blebs that might have popped

  • Drains

    • Seldinger

    • Argyle

  • Recurrence

    • 54% risk within 4 years

    • Esp. if still smoking

  • Chest drain management

    • Check swinging

    • If still bubbling, can use 5 cm water pressure to suck air out

Asthma

• • Formoterol

    • Rapidly acting beta2 agonist; Also long-acting

  • Peak flow

    • 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%

  • MgSO4

    • Antagonises calcium release in smooth muscle

    • Can only use once

    • Causes muscle weakness / resp. failure

  • Aminophylline

    • 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%

    • PEFR >75%

    • < 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

COPD

• • Pathophysiology - Due to toxious stimuli

    • Elastin/connective tissue defect

      • Loss of elastic recoil

      • => Emphysema

    • Inflammation

      • Mucous plugging + airway defects

      • => Bronchitis

  • Admit to ICU if acidotic with pH <7.25

Anthonisen criteria

• • For antibiotic use in acute exacerbation of COPD

  • Need 2 out of 3 of:

    • Increased dyspnea

    • Increased sputum volume

    • Increased sputum purulence

Notes

• • 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