Asthma and COPD Flashcards
Risk factors for severe/ fatal asthma:
Fulminant (sudden onset, <3hrs)
Intrinsic (ie. no known triggers, non-atopic)
Previous ICU/ intubation
>2 hospitalisations OR >3 ED visits in 12 months
>2 reliever canisters per month
Low SES
Poor compliance
Comorbid lung disease
Psychiatric disease
Clinical features of CRITICAL/ (impending respiratory arrest) asthma:
Confused/ agitated/ obtunded
Exhausted/ WOB reduced
Paradoxical breathing
‘Silent chest’
Sats < 90%, cyanosis
Hypercarbia, acidosis
–> CO2 should be LOW, not normal
Clinical features of mild/mod/sev/critical asthma:
SEVERE
- Sats < 90%
- FEV1/peak flow< 40% predicted
MODERATE
- Sats < 92%
- < 60% predicted
MILD
- Sats > 92%
- > 60% predicted
Differentials for acute asthma attack:
Anaphylaxis
Carcinoid
Scombroid
Upper airway obstruction
Foreign body
Vocal cord dysfunction
PTx
Pneumonia
ARDS/ pneumonitis / aspiration
COPD
PE
CCF (‘cardiac asthma)
Anxiety
Significance of pulsus paradoxus in acute asthma:
Differential in strength of pulse in inspiration (diminished) vs expiration
–> marker of increased intrathoracic/restrictive cardiac pressures
(or 25mmHg + difference with art line)
Present in mod/sev asthma. Gone again when periarrest.
Role of CXR in severe asthma:
Not routine unless:
Severe/ critical
Suspected:
-Barotrauma (PTx, pneumomed)
-LRTI
-DDx
ESTABLISHED medications in asthma Mx:
ESTABLISHED
1- OXYGEN
- Keep sats 92% and above
2-SALBUTAMOL (Beta-agonist)
MILD: (1dose)
- <6yo 6 puffs
>6yo 12 puffs
OR
- 1x 5mg neb
MOD (1 Burst dose)
- 6 or 12 puffs x3 in 60mins
OR
- 1x 5mg neb x3 in 60mins
SEV (Continuous dosing)
- Continuous burst MDI or neb
- If not moving air:
- IV 5microg/kg (max 250) bolus
—> 5microg/kg/ min (adult)
–> 1microg/kg/min (paed)
3-IPRATROPIUM (Anticholinergic)
MILD
- No role
MOD (1burst)
- Add
- <6yo 4 puffs, >60yo 8 puffs x3 in 60mins.
OR
- 250-500microg neb x3
SEV
- As above
- Max ONE burst. Antichol. Dries up secretions —> plugs.
4-STEROID
when any need for ongoing salbutamol post DC. IV not superior.
MILD/MOD
- PO Prednisolone 60mg (2mg/kg) stat, then (1mg/kg) for 2 days
SEV
- IV Hydrocort 200mg (4mg/kg) 6 hourly
OR
Methylpred 1mg/kg 6 hourly
NON-ESTABLISHED medications in asthma Mx:
MAGNESIUM (50%)
2g (or 50mg/kg) MgSO4 over 20mins. Repeat 30minutely or run central infusion.
- Aim Mg <4
AMINOPHYLLINE
2012 Cochrane found no benefit in adults
- IV 6-10mg/kg load –> infusion/Q6H dosing then titrated to serum level
ADRENALINE
Standard infusion
1-5microg/min and titrate
KETAMINE
Sub-dissociative dose
ie. 0.1-0.3mg IV Q10min
OR
0.1mg/kg/hr infusion
OTHER:
Inhalational anaesthetics
Heliox
Discharge requirements for asthma:
MILD, or rapidly responsive MOD
Salbutamol stretched to 3 hours
No O2 requirement
FEV1/peak flow >60% expected
No risk factors for severe/fatal
Oral intake
-Written action plan
-Inhaler technique observed
-2 days PO steroids if ongoing reliever requirement
-GP/paeds follow up within 24 hours
-Safety net advice
-Advice re smoke exposure/ immunisation
Intubation approach in asthma:
ONLY IF NECESSARY! High morbid/mortal. Try NIV first if can.
INDUCTION
Consider DSI with NIV
Preload with fluid
Allow passive expiration x1
If acidotic, gently bag through apnoeic period
Consider lignocaine preTx- no evidence
Ketamine + roc
VENTILATION
Obstructive strategy
Watch for dynamic hyperinflation
High risk barotrauma
Will require high PIPs
What might the ECG of a COPD patient show?
P mitrale
—> RA dilation
RVH/ RAD
Right heart strain
—> V1-3 STD, TWI
RBBB
How can O2 do harm in COPD?
1- Stops hypoxic resp drive (chronic retainer)
2- Vasodilation to dodgy alveoli —> worsens VQ mismatch
3- Haldane effect (when oxygenated, Hb offloads CO2 into blood)
Management of COPD exacerbations:
O2 to 88-92%
ANTICHOL
Ipratropium
500microg neb Q4-6H —> continuous
6 puffs, PRN
OR
Salbutamol
5mg neb, PRN
8-10 puffs MDI, 20-minutely PRN
(antichol/ SABA equally effective. Antichol lasts a bit longer and better tolerated. Combining them has no benefit)
AND
Prednisolone 30-60mg, for 5 days
Hydrocortisone 5mg/kg (adult 250mg) IV Q6H
IF INEFFECTIVE:
Augmentin 875/125g BD for 5 days
Doxy 100mg daily
As per CAP.
(Must cover H. Influenzae, M. catarrhalis)
IF FAILING 1 hour OPTIMAL MMX:
BiPap
Severe: as per asthma- try aminophylline, MgSo4
——————
Extras
Chest PT
Smoking cessation
Pneumococcus/ flu/ Hib vaccines
Need for home O2
Which COPD patients are prone to hypercarbic failure?
BLUE BLOATER:
- Fat, chronic productive cough
- Cor pulmonale, pulm HTN—> CCF, polycythaemia
- Loss of CO2 drive
—> O2 can cause retention
Don’t struggle. Silently get obtunded
PINK PUFFER:
- Working hard, tripodding
- Barrel chest, cachexic
- Bullae —> PTx
- Responsive to CO2, will compensate
Struggle, resp distress +
Role of AMINOPHYLLINE in asthma:
For use in children with severe asthma.
No evidence for use in adults, but can be tried
