CHHS18/136

Canberra Hospital and Health ServicesClinical Guideline Pharmacological management of severe/critical exacerbation of asthma (infants, children and adolescents) Contents

Contents....................................................................................................................................1

Guideline Statement.................................................................................................................2

Scope........................................................................................................................................ 3

Section 1 – Classification of asthma severity............................................................................3

Section 2 – Intravenous Magnesium.........................................................................................5

Section 3 – Intravenous aminophylline.....................................................................................8

Section 4 – Intravenous Salbutamol........................................................................................10

Related Policies, Procedures, Guidelines and Legislation.......................................................12

References.............................................................................................................................. 12

Search Terms.......................................................................................................................... 12

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Guideline Statement

This document guides the use of intravenous (IV) magnesium, IV aminophylline and IV salbutamol in the management of an infant, child or adolescent at Canberra Hospital and Health Services (CHHS with a severe/critical exacerbation of asthma.

A severe/critical exacerbation of asthma is identified by: Agitation, confusion or drowsiness Moderate to severe increased work of breathing or exhaustion Unable to speak in sentences or at all Weak cry Sp02 <90% in room air (RA) Marked tachycardia or bradycardia Soft or absent breath sounds

It should be noted that this document reflects what is currently regarded as a safe and appropriate approach to care. However, as in any clinical situation there may be factors which cannot be covered by a single set of guidelines, this document should be used as a guide. It does not replace the need for the application of clinical judgment to each individual presentation.

BackgroundThis document has been developed to be used in conjunction with CHHS Clinical Guideline “Paediatrics: Infants and Children - Acute Management of Asthma Clinical Practice Guideline” which can be found on the Policy Register (http://inhealth/PPR/default.aspx).

Key ObjectiveThis clinical guideline is intended to guide the care of infants, children and adolescents with an acute/critical exacerbation of asthma at CHHS.

It is suggested that the decision to commence the use of IV magnesium, aminophylline or salbutamol in the asthmatic child is to be made by an Emergency Department (ED) Consultant or Paediatrician (ideally the Respiratory Paediatrician on call) who is familiar with the overall management of severe/critical asthma.

Alerts These children are to be cared for in a high dependency environment, with staffing

ratios and prescribed frequency of medical review to be discussed with the consultant medical officer and clinical nurse consultant.

The paediatric respiratory consultant on call may be contacted to discuss the management of paediatric patients with severe or critical exacerbation of asthma. Contact via CHHS switchboard on 02 6244 2222.

Consider contacting Newborn & paediatric Emergency Transport Service (NETS) for clinical advice/guidance. Telephone 1300 362 499.

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Ensure all relevant information regarding treatment and side effects is discussed with patient/parent/carer where possible to ensure informed consent as per Consent and Treatment policy

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Scope

This document applies to the following CHHS staff working within their scope of practice: medical officers registered nurses medical and nursing students under supervision.

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Section 1 – Classification of asthma severity

Initial Severity AssessmentTreat in the highest category in which any symptom occurs

Symptoms MildLikely to go home

ModeratePossibly be admitted

Severe and Life ThreateningWill be admitted or transferred

Oximetry in Air >94% 90-94% <90%Heart rate Close to normal range for

ageMild-Moderate Tachycardia for age

Marked Tachycardia - beware relative Bradycardia for age

(age appropriate)Ability to talk in:

Sentences or Long vigorous Cry

Phrases or Shortened Cry

Words / Weak Cry or Unable to Speak / Cry

Accessory Muscle Use None Mild to Moderate Moderate to SevereAltered Consciousness Alert

Age AppropriateEasily Engaged Age Appropriate

Be concerned if Agitated or Drowsy or Confused

Cyanosis in air None None Any Cyanosis is very concerning

TreatmentGet consultant help then Call NETS 1300 36 2500

Oxygen No To maintain SaO2 >94% To maintain SaO2 >94% Consider High flow Oxygen

Salbutamol 100 micrograms Metered Dose Inhaler(MDI) & Spacer

<6 years 6 x puffs stat≥6 years 12 x puffs statreview frequently and repeat when required

<6 years 6 x puffs≥6 years 12 x puffsGive 20 minutely x 3 then repeat as required

Severe – see page 10<6 years 6 x puffs≥6 years 12 x puffsGive 20 minutely x 3 with Ipratropium ReassessOR

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Initial Severity AssessmentTreat in the highest category in which any symptom occurs

Salbutamol NebulisedNot recommended Not recommended

Life Threatening - Continuous nebulised Salbutamol (5mg/mL undiluted) with Ipratropium(3 doses as below) until improvement Reassess

Ipratropium (Atrovent) 20 micrograms(3 doses always together with Salbutamol)

No Consider 20 minutely x 3<6 years - 4 puffs MDI≥6 years - 8 puffs MDI

Yes - 20 minutely x 3<6 years - 4 puffs MDI or 250mcg Neb Ipratropium≥6 years - 8 puffs MDI or 500mcg Neb Ipratropium

No or Poor response to Treatment

Check diagnosis and treat as per Moderate

Check diagnosis and treat as per Severe and Life Threatening

Immediate Senior Review-Consult PICU (via NETS if outside a children’s hospital)

If contemplating giving any of IV Salbutamol, IV Aminophylline or IV Magnesium Sulphate

Not applicable Not applicableIf no or poor response to Nebulised Salbutamol, contact senior help or PICU via (NETS 1300 36 2500) for discussion regarding retrieval

Systemic corticosteroidsConsider Oral Prednisone 1-2mg/ kg depending on history and response to treatment

Oral Prednisone 1-2mg/kg

Hydrocortisone IV 4mg/kg or Methylprednisone IV 1mg/kg

Investigations Nil (routine) required Nil routine requiredConsider Chest X-ray if focal signs

Consider Blood Gases, Chest X-ray and UEC

Observation & Review

Observations (HR, RR and O2 Sats) pre and post treatment – minimum hourly for 3 hours. MO review prior to discharge

Continuous observations (HR, RR and O2 Sats).Observations pre and post treatment –initially Q 30min then MO review within 1 hour

Continuous cardiorespiratory monitoring (HR, RR and O2 Sats) Regular medical review

Disposition Home if Salbutamol requirement>3 hourly See ‘Discharge Criteria’

Observe for 3 hours after last dose. If not suitable for discharge then – Admit or Transfer.Otherwise home.

Admit to Level 4 facility or above if improving or retrieve to Paediatric ICU (call NETS)

(from CHHS 15/134 Paediatrics – Acute Management of Asthma Clinical Practice Guideline)

Section 2 – Intravenous Magnesium

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It is expected that the decision to commence IV Magnesium be made in consultation with an ED Consultant or Paediatrician who will be familiar with the mechanism of action of the medication and any contra-indications.

Magnesium should be considered in a severe/critical exacerbation of asthma when maximum bronchodilator therapy has been used.

Nursing care considerations The child receiving intravenous magnesium should be cared for in a high dependency

setting Measure and record a full set of baseline observations and conduct a full respiratory

assessment on the patient before the infusion is commenced. These observations should be done half hourly during the loading dose, and hourly for the duration of the infusiono Baseline observations: respiratory rate, heart rate, temperature, blood pressure,

Sp02, oxygen requirement and work of breathing including recession, accessory muscle use, tracheal tug, head bob, nasal flare and grunting

o Full respiratory assessment: respiratory rate, work of breathing, chest auscultation assessing air entry and breath sounds

o Include central capillary refill, child’s colour and level of consciousness Continuous cardio-respiratory and oximetry is required Maintain an accurate fluid balance chart Obtain baseline venous blood gas, urea, creatinine and electrolytes including

magnesium. Further investigations may be done at the discretion of medical staff

Dose Dose should be based on Lean Body Weight (LBW) whenever the patient’s actual weight

is 20% more than their LBW. This is based on the percentile chart and the expectations of average growth.

Dose: 50mg/kg of magnesium

Note: There are two brands of Magnesium Sulphate IV solution stocked at the Canberra Hospital and Health Services - 49.3% (2.47g/5mL) ampoules and 50% (5g/10mL) vials. Both products are known as ‘50%’ and both products are considered to provide 2mmol/mL of Magnesium ions.

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How to administer intravenous Magnesium SulphateThe 500mg/mL (2mmol/mL) solution must be diluted to 200mg/mL (0.8mmol/mL) or weaker before infusing.To make a 200mg/mL solution –Dilute 5ml of magnesium sulphate 50% (500mg/mL) to 12.5mL with sodium chloride 0.9%Dilute 10mL of magnesium sulphate 50% (500mg/mL) to 25mL with sodium chloride 0.9%Dilute 20mL of magnesium sulphate 50% (500mg/mL) to 50mL with sodium chloride 0.9%

Dose should be based on Lean Body Weight (LBW) whenever the patient’ actual weight is 20% more than their LBW. This is based on the percentile chart and the expectations of average growth.

Loading DoseAdminister over 20 minutes

50mg/kg (0.1mL/kg of 50% magnesium sulphate 500mg/mL solution)= 50mg/kg (0.25mL/kg) of 200mg/mL diluted solution

Example 15kg child = 50mg/kg x 15kg = 750mg= 50mg/kg (0.25mL/kg of 200mg/mL diluted solution) x 15kg

= 3.75mL of 200mg/mL (750mg)Infuse 750mg (3.75mL of 200mg/mL) over 20 minutes (ie at 11.25mL/hr for 20 minutes)

Example 38kg child = 50mg/kg x 38kg = 1900mg= 50mg/kg (0.25mL/kg of 200mg/mL diluted solution) x 38kg

= 9.5mL of 200mg/mL diluted solution (1900mg)Infuse 9.5mL over 20 minutes (ie at 28.5mL/hr for 20 minutes)

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Maintenance DoseInfusion

30mg/kg/hr (0.06mL/kg/hr of 50% magnesium sulphate 500mg/mL solution) =30mg/kg/hr (0.15mL/kg/hr of 200mg/mL magnesium sulphate diluted solution)

Example 15kg child = 30mg/kg/hr x 15kg = 450mg/hr= 30mg/kg/hr (0.15mL/kg/hr of 200mg/mL diluted solution) =450mg/hr

= 2.25mL/hour using 200mg/mL diluted solution

Example 38kg child = 30mg/kg/hr x 38kg =1140mg/hr= 30mg/kg/hr (0.15mL/kg/hr of 200mg/mL diluted solution) =1140mg/hr

= 5.7mL/hour using 200mg/mL diluted solution

WARNING: Rapid infusion may cause hypotension

Dosage and administration guidelines Magnesium and aminophylline are incompatible and must be given via separate IV lines Prescriptions for magnesium must be written on an Intravenous Fluid Orders chart Infusions should be prepared and administered in a timely manner. During business

hours, the Pharmacy Department IV Room will prepare magnesium infusion solutions, however to avoid delays in administration, solutions may be prepared in clinical areas.

Magnesium infusions MUST be run using medication safety infusion pumps. Using the Critical Care Drug Library select Magnesium Sulphate (not Maternity

Magnesium) and pump will require mmol/ml

Side effects of magnesium include: Nausea and vomiting Hypotension Respiratory depression Cardiac arrhythmias CNS depression Muscle weakness Blurred or double vision Muscle paralysis

Practice points IV Magnesium may be administered via peripheral or central access. Ensure adequate dilution as per table above Check IV site regularly to avoid extravasation Incompatible with aminophylline

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Section 3 – Intravenous aminophylline

It is expected that the decision to commence IV aminophylline be made in consultation with an ED Consultant or Paediatrician who will be familiar with the mechanism of action of the medication and any contra-indications.

Aminophylline is a bronchodilator, used in children with severe/critical asthma, receiving maximised treatment with inhaled bronchodilators. It is a drug with a narrow therapeutic range and requires careful dosing, administration and monitoring as side effects can occur even at therapeutic levels. Aminophylline is the intravenous form of theophylline. 1 mg of aminophylline = 0.8mg of theophylline.

Nursing care considerations The child receiving intravenous aminophylline should be cared for in a high dependency

setting Measure and record a full set of baseline observations and conduct a full respiratory

assessment on the patient before the infusion is commenced. These observations should be done half hourly during the loading dose, and hourly for the duration of the infusiono Baseline observations: respiratory rate, heart rate, temperature, blood pressure,

Sp02, oxygen requirement and work of breathing including recession, accessory muscle use, tracheal tug, head bob, nasal flare and grunting

o Full respiratory assessment: respiratory rate, work of breathing, chest auscultation assessing air entry and breath sounds

o Include central capillary refill, child’s colour and level of consciousness Continuous cardio-respiratory and oximetry is required Maintain an accurate fluid balance chart Obtain baseline venous blood gas, urea, creatinine and electrolytes. Further

investigations may be done at the discretion of medical staff

Dosing informationDose should be based on Lean Body Weight (LBW) whenever the patient’s actual weight is 20% more than their LBW. This is based on the percentile chart and the expectations of average growth. Reduce dose in patients with hepatic impairment.

Loading Dosage For patients already on maintenance theophylline therapy – discuss drug interactions with

pharmacist so that dose adjustments (“Modified Loading Dose”) may be calculated.

Loading dose for patients not already on maintenance theophylline therapy:

Children aged 12months to 16 years 10 mg/kg (maximum 500mg) Infants aged 1-12 months 5mg/kg

Dilute to 1mg/mL (or weaker) using sodium chloride 0.9% or 5% dextrose

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Administer over 1 hour

WARNING: Rapid infusion of aminophylline can cause dangerous Central Nervous System (CNS) and cardiovascular effects such as bradycardia and severe hypotension.

Aminophylline administration information Aminophylline and magnesium are incompatible and must be given via separate IV lines Prescriptions for aminophylline must be written on an Intravenous Fluid Order chart Infusions should be prepared and administered in a timely manner. During business

hours, the Pharmacy Department IV Room will prepare aminophylline infusion solutions, however to avoid delays in administration, solutions may be prepared in clinical areas

All aminophylline infusions should be run using medication safety infusion pumps. The BBraun infusion pumps have ‘Aminophylline Loading Dose’ and ’Aminophylline Maintenance Dose’ options.

Side effects of aminophylline include:Common: Nausea and vomiting. This should not usually lead to discontinuation of therapy Sinus tachycardia

Rare: Other dysrhythmias are rare unless there is concurrent hypokalaemia (salbutamol

administration can exacerbate hypokalaemia) Seizures are rare with therapeutic levels

Therapeutic Drug Monitoring Patients may require therapeutic drug monitoring (TDM) whilst being treated with

intravenous aminophylline as the pharmacokinetics of theophylline are very variable. Discuss with the pharmacist

Should TDM be necessary, target serum theophylline concentration is 10-20mg/L (55 to 110 micromol/L); this provides optimum bronchodilation with minimal adverse effects

A bolus correction dose (over 1 hour) of 0.6mg/kg LBW aminophylline is expected to raise the plasma theophylline level by 1mg/L (5.5 micromol/L)

Serum potassium levels may decrease during aminophylline infusion Tobacco and marijuana smoking and alcohol consumption increase the body’s clearance

(decrease levels) of theophylline. Higher doses may be required in these patients. Aminophylline interacts with many drugs (e.g. antibiotics, anticonvulsants) and levels

can be affected. Monitor levels or consult pharmacy for advice on dose adjustments

Practice points Aminophylline is available in 25mg/mL, 10mL ampoules. Do not use if crystals are

present; protect ampoules from light only during storage. Aminophylline is basic (pH ~9) so to prevent extravasations ensure adequate dilution

and check IV site hourly.

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Section 4 – Intravenous Salbutamol

It is expected that the decision to commence IV Salbutamol be made in consultation with an ED Consultant or Paediatrician who will be familiar with the mechanism of action of the medication and any contra-indications.

Nursing care considerations The child receiving intravenous salbutamol should be cared for in a high dependency

setting Measure and record a full set of baseline observations and conduct a full respiratory

assessment on the patient before the infusion is commenced. These observations should be done half hourly during the loading dose, and hourly for the duration of the infusiono Baseline observations: respiratory rate, heart rate, temperature, blood pressure,

Sp02, oxygen requirement and work of breathing including recession, accessory muscle use, tracheal tug, head bob, nasal flare and grunting

o Full respiratory assessment: respiratory rate, work of breathing, chest auscultation assessing air entry and breath sounds

o Include central capillary refill, child’s colour and level of consciousness Continuous cardio-respiratory and oximetry is required Maintain an accurate fluid balance chart Obtain baseline venous blood gas, urea, creatinine and electrolytes Further investigations may be done at the discretion of medical staff

Administration GuidelinesDO NOT DILUTE.

Ventolin Obstetric is safe to use UNDILUTED - undiluted use in the treatment of paediatric asthma allows for better fluid balance in the patient.

Prescriptions for salbutamol infusion must be written on an Intravenous Fluid Order chart

Infusions should be prepared and administered in a timely manner. During business hours, the Pharmacy Department IV Room will prepare salbutamol infusion solutions, however to avoid delays in administration, solutions may be prepared in clinical areas

All salbutamol infusions should be run using medication safety infusion pumps. The BBraun infusion pumps have ‘Salbutamol Loading Dose’ and ’Salbutamol Maintenance Dose’ options.

Salbutamol Dose: Loading: 5 mcg/kg/min for one hour Maintenance: 1-2 mcg/kg/min (maximum dose of 10microg/kg/min)

Weaning IV salbutamol infusionsDoc Number Version Issued Review Date Area Responsible PageCHHS18/136 1 27/04/2018 01/03/2021 WY&C -

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Care must be taken when increasing or decreasing infusion rates. IV salbutamol has a half-life of 4-6 hours & serum levels can take many hours to stabilise following a change in infusion rates. Observe the patient closely in this phase

Infusion rate should be reduced slowly as per medical orders & the patient monitored for up to 12 hours

If the child remains stable on the reduced dose the infusion may be ceased If the child’s condition deteriorates, the patient must be reviewed by the paediatric

resident and the Paediatrician notified. IV salbutamol infusion may need to be recommenced at the child’s previous dose ordered on the medication chart

Side effects of IV salbutamol include fine muscle tremor tachyarrhythmia hypokalaemia restlessness sweating headache and dizziness hyperglycaemia fluid overload

Management and response to side effects should be guided by the senior medical staff in consultation with the Paediatrician.

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Related Policies, Procedures, Guidelines and Legislation

PoliciesMedication Handling Policy

ProceduresVital Signs & Early Warning Scores

Guidelines Paediatrics: Infants and Children - Acute Management of Asthma

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References

1. National Asthma Council Australia. Australian Asthma Handbook, Version 1.3. National Asthma Council Australia, Melbourne, 2017. Website. Available from: http://www.asthmahandbook.org.au

2. Royal Children's Hospital, Melbourne, Australia, Clinical Practice Guideline on Asthma Acute, [Internet, last updated May 2015; cited 8 December 2017], Available from: https://www.rch.org.au/clinicalguide/guideline_index/Asthma_acute/

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Search Terms

Asthma, Respiratory, Magnesium, Aminophylline, Theophylline, Ventolin, Salbutamol

Disclaimer: This document has been developed by ACT Health, Canberra Hospital and Health Services specifically for its own use. Use of this document and any reliance on the information contained therein by any third party is at his or her own risk and Health Directorate assumes no responsibility whatsoever.

Policy Team ONLY to complete the following:Date Amended Section Amended Divisional Approval Final Approval 21/02/2018 Complete Review Liz Chatham, ED WY&C CHHS Policy Committee

This document supersedes the following: Document Number Document NameCHHS14/023 Paediatrics – Asthma – Pharmacological Management of Severe/Critical

Exacerbation of Asthma

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