RESPIRATORY

ResponseDaytime symptoms >=2days/week
Need reliever >2 days/week
Limitation on activities
Any symptoms during night or on walking
>=3 presentations to ED in 1 month
Prior ICU admission
Poor social situation/health literacy/concordance/compliance

ResponseThink Patient factors, disease factors, social factors
Medication plan (steroid/inhaler weening plan)
Medication/scrips and ensure able to buy medications
Preventer
Inhaler + spacer technique education
Discharge instructions (medications/asthma plan/follow up/return to ED)
Follow up with GP/Resp physician
Interpreter for above if NESB

ResponseInability to talk in full sentences
O2 saturations <90%, PaO2 <60
PaCO2 >45
Use of accessory muscles, tracheal tug
Pulsus paridoxus >15 mm.Hg
Quiet chest
Unable to lay supine
Cyanosis, sweating
Confusion, decreased LOC
Bradycardia +/- hypotension herald arrest

ResponseConsciousness - agitated or drowsy
Marked increased work of breathing
Silent chest
Inability to talk
Tachypnoea
Tachycardia
Hypotension
hypoxia

ResponseOxygen via mask to keep sats >92%
Salbutamol back to back nebs <6 = 2.5mg, >6=5-10 mg
Ipratropium q20 mins for 1 hr (<6 250 mics, >6 500 mics)
Steroid IV - Hydrocortisone 4mg/kg
IV magnesium (50 mg/kg or adult 10 mmol)
Salbutamol 250 mics IV followed by 5-10 mics/kg/min infusion
Aminophyline 10 mg/kg loading dose
Bipap 10/5,
Adrenaline 300 mics IM or infusion

Response250 mics stat >> 5-10 mics/kg/min

Indication: Critical/severe asthma where inhaled B-agonist cannot be effectively delivered (eg: Ventilated patients).
Poor evidence to support IV (in addition or replacement) vs inhaled beta agonists.
Efficacy in paediatric population unclear due to lack of good trials

Adverse
Increased autonomic adverse effects (compared to inhaled)
Increased HR
Hypokalaemia
Lactic acidosis

ResponseIndications: Severe asthma (no benefit in mild/moderate asthma)
Reduces need for admission and improves some lung function parameters in patients with severe asthma who have not responded sufficiently to usual treatments
Paeds - evidence weak. May reduce admission in mod-severe asthma

Adverse
CNS depression/Depressed tendon reflexes
Muscle weakness
Flushing
Depressed cardiac function
Respiratory depression

ResponsePros:
Extrinsic PEEP decreased WOB by helping overcome auto-peep
Extrensic IPAP may increase tidal volume by decreasing the work done against airway resistance
Shorter inspiratory times may increase tidal volumes without causing an extra dynamic hyperinflation
NIV may prevent intubation in a select group of patients
Decreases work of breathing

Cons:
May delay intubation. Have intubation equipment ready in case NIV fails
Inappropriate setting may increase the effort of breathing
Increased positive airway pressure increased risk or pneumothorax/barotrauma
Addition of extrinsic PEEP which is higher than intrinsic PEEP will exacerbate dynamic hyperinflation
NIV makes it more difficult to clear secretions if there is a strong infective component.

Evidence
BIPAP is mode of choice
Few small studies using NIV in asthma patients show promising results
Large cochrane review suggests large randomised control trial required

ResponseKeep upright until last moment
Preoxygenate (bipap or 15L/min NRBM)
High flow oxygen via nasal cannula 15L/min
Continuous salbutamol nebs 10-15mg/h
N/S 1L IV bolus

ResponseTidal volume 6 mL/kg (max 8)- lung protective ventilation, reduce barotrauma
RR 10 - (may need to reduce as low as 6) - reduce gas trapping, permissive hypercapnia
I:E ratio 1:3-1:4 (severe 1:5) - reduce gas trapping, allow adequate time for expiration
FiO2 - titrate to spO2>92%
PEEP - controversial, 0-5 cm.H2O
Limits - Peak inspiratory pressure <35, Plateau pressure <20 cm.H2O

ResponseDynamic hyperinflation (air trapping)
Tension pneumothorax
Induction drugs >> hypotension
Anaphylaxis
Myocardial depression
Hypovolaemia
DOPES… I have left in resp as asthma specific

ResponseDisconnect from ventilator, allow prolonged exhalation
IV fluid bolus 10-20 mL/kg
Rule out tension PTx - Clinical/US/CXR or needle/finger thoracostomy