asthma_paed_severe

see also:

**oxygen**to maintain SaO2 > 92%- use high flow intranasal oxygen if needed

- contact senior staff ASAP and move patient to a resuscitation cubicle
**continuous salbutamol nebulisers**(0.5% undiluted) until infusions are commenced**nebulised ipratropium**20 minutely x 3 doses, added to salbutamol:- <20kg: 250 mcg nebule/dose
- >20kg: 500 mcg nebule/dose

- iv access x 2
- take bloods for FBE, U&E, lactate and serial venous blood gas as needed
- arterial blood gases are usually not needed but if intubated, then consider via arterial line

**methylprednisolone**1 mg/kg i.v. 6-hourly- alternatively, can use iv hydrocortisone 4mg/kg 4-6hrly

- portable CXR to exclude complications of asthma

- if in extremis, may need to intubate then start infusions
- if not a tertiary paediatric hospital, contact the tertiary hospital to arrange
**retrieval service**and transfer

- the following are as per RCH ICU 2008

- use 50ml obstetric salbutamol solution (1mg/ml) undiluted
- determine base infusion rate for 1mcg/kg/min = wt x 0.06 ml/hr
- for those over 40kg, calculate as if 40kg
^{1)} **load dose**is 5-10mcg/kg/min for 1 hour = 5-10 x the base infusion rate calculated above- many give a load dose of 5mcg/kg over 10min
^{2)}but this is nonsensical if they then advise initial maintenance infusion rate of 5mcg/kg/min, titrated to 1-10mcg/kg/min

**maintenance rate**is 1-2mcg/kg/min = 1-2 x the base infusion rate calculated above

- use in addition to iv salbutamol, if inadequate response to iv salbutamol or child is in extremis
- must be given in separate line to iv salbutamol (hence the 2nd iv access line)
- set up infusion by adding 25mg/kg aminophylline to 5% dextrose to make total of 50mls = 0.5mg/kg/ml
- if patient is NOT on aminophylline or theophylline then give a
**LOADING DOSE**:- 10mg/kg (max. 500mg) over 1 hour = 20ml/hr if weight < 50kg, otherwise 500mg/(0.5mg/kg x weight in kg) ml/hr

**maintenance aminophylline infusion:**- age 1-9 years:
- rate = 1.1mg/kg/hr = 2.2ml/hr if using 0.5mg/kg/ml infusion as above

- age 10 yrs and over:
- rate = 0.7mg/kg/hr = 1.4ml/hr if using 0.5mg/kg/ml infusion as above

- may be of benefit
**load dose infusion**50mg/kg of magnesium sulphate infused over 20min:- 0.1ml/kg of 50% magnesium sulphate diluted to 20ml with 0.9% saline and infuse at 1ml/min for 20min.

**maintenance infusion**:- 0.12mmol/kg/hr (to max. 8mmol/hr) = 0.06ml/kg/hr (max. 4ml/hr) of 50% solution (2mmol/ml)
- aim for target serum magnesium level of 1.5-2.5mM

- especially if poor response or becoming tired and rising PCO
_{2}: - experienced staff - consider calling anaesthetics to assist
- ensure equipment and medications checked and ready as per usual rapid sequence induction

- consider iv ketamine as induction agent as has bronchodilator properties
- neuromuscular relaxants at induction (eg. suxamethonium 1.5mg/kg)

- maintenance neuromuscular relaxants
- eg. vecuronium 0.1mg/kg every 30min or so

- maintenance sedation
- CXR post-intubation
- care with ventilation (see below)
- arterial line to monitor blood gases

- the prime aims are to ensure:
- maintenance of oxygenation SaO2 > 92%
- maintenance of near-normal pCO
_{2}levels 35-45 mmHg - minimise risk of iatrogenic pneumothorax
- minimise risk of iatrogenic air trapping and resultant impaired venous return which may result in hypotension and pulseless electrical activity (PEA)

- aim for prolonged expiratory phase and lower respiratory rate than normal (eg 8-12/min for adolescent)

asthma_paed_severe.txt · Last modified: 2020/01/07 13:47 (external edit)