Asthma Exacerbations and Therapeutic Positioning

Cite this article as:
Henry Goldstein. Asthma Exacerbations and Therapeutic Positioning, Don't Forget the Bubbles, 2014. Available at:
https://doi.org/10.31440/DFTB.5300

The idea: Sitting erect vs slouching or slumping improves airflow in moderate-severe exacerbations of asthma

A pale, breathless 7-year-old with a known history of asthma presents to your department. Oxygen saturations are hovering in the mid-’80s with marked tracheal tug, subcostal, substernal, intercostal and supraclavicular recessions in addition to accessory muscle usage. He’s moving air and there’s a widespread wheeze throughout the chest. This child has a moderate-severe exacerbation of asthma.

In addition to commencing standard management including O2, salbutamol, steroids, IV access for a VBG (and considering some MgSO4), you notice that he’s sliding down the bed and curling into a ball.

The Therapeutic Guidelines for Asthma Management recommend nursing the patient sitting upright, but this can be quite challenging, especially if the child keeps sliding down the bed.

Anecdotally, I’ve seen more than a dozen children in this setting whose SpO2 has improved in less than a minute after adequate re-positioning, in adjunct to standard management.

To ameliorate some of these challenges, it’s my practice to prop children in order to remain sitting upright. I was first taught some of these tips by Dr. Tom Hurley, Paediatrician on Queensland’s Sunshine Coast, and added a few of my own. I’ll describe my method for positioning a child upright (and getting them to stay there!) in the context of an exacerbation of asthma.

You will need:

  • To first initiate standard management for asthma!
  • A bed that sits up and has rails.
  • 3-5 pillows/rolled up blankets or twice as many towels, rolled up.

What to do:

  1. Tell the child and parent what you’re going to do, and why it’s helpful.
  2. Make sure you can see as much of the anterior chest as dignified and practical; one of the main benefits of this positioning is that you can better observe the child’s work of breathing from the end of the bed.
  3. Ramp up the head of the bed to being almost straight up; most beds will top out about 70 degrees, which will be sufficient.
  4. Lift the child so their back is to the bed and their bottom is at the crease in the bed.
  5. Place a blanket under their thighs as a wedge; this will stop them sliding down.
  6. Additionally, if your supply of towels is plentiful, you can make a number of rolls side by side to the foot of the bed. This means the child can push on them with their feet.

Postioning for asthma exacerbation - lateral view

  1. Next, we want to prevent the child from slumping to either side.
  2. Put up the rails and wedge the pillows next to the child’s torso, across the width of the bed. For smaller children, you can place the pillows flat, for larger kids you might need to place them on their edge. Either way, they shouldn’t be able to crumple off to one side if they get exhausted or fall asleep.

Postioning for asthma exacerbation - anterior view

  1. Additionally, if you still have spare pillows, you can position the pillows to stop the child’s head from rolling side to side.
  2. Now, crack on with the rest of this child’s management!

Although I’m a bit uncertain on the science behind all this benefit, we’re taught in medical school about “tripoding”;  most of us are familiar with the ‘tripod prayer’ seen in adults with exacerbations of COPD. It’s just a theory, but I suspect that once in bed, children don’t adequately tripod.

Firstly, they just don’t know how to position themselves, either because breathlessness is a new sensation or they’re too young. Secondly, kids simply don’t have the levers to adequately tripod against their surroundings. Thirdly, once in a large hospital bed, the surroundings are soft and squishy, reducing the efficacy of uncoordinated tripoding. Fourthly, the improved PEFR in the erect vs supine position is well demonstrated in a number of experiments done in the 1960s and 1980s (see references). Lastly, the V/Q mismatch that occurs in asthma might further benefit from an upright position.

In the spirit of #FOAMPed, I thought I’d float this out there and see if anyone has other methods of optimizing positioning for these patients.

 

Selected references

Haffejee, I E., Effect of supine posture on peak expiratory flow rates in asthma. Arch Dis Child 1988 63: 127-129

Moreno F, Lyons HA. Effect of body posture on lung volumes. J Appl Physiol. 1961 Jan;16:27-9. https://www.ncbi.nlm.nih.gov/pubmed/13772524

Asthma – medical management

Cite this article as:
Tessa Davis. Asthma – medical management, Don't Forget the Bubbles, 2013. Available at:
https://doi.org/10.31440/DFTB.2815

A 9 year old boy is rushed into ED with what is clearly a severe exacerbation of his asthma. His sats are 80%, his RR is 60-70 and he is not looking great. You can hear some air entry with a bit of wheeze. He clearly needs some good treatment and he needs it quickly. Which drugs you choose? 

Bronchiolitis

Cite this article as:
Henry Goldstein. Bronchiolitis, Don't Forget the Bubbles, 2013. Available at:
https://doi.org/10.31440/DFTB.3581

A 6-month-old child presents with cough and runny nose for 2 days with increased work of breathing.  She is working hard with moderate subcostal recession. Once you hear the cough, it can only mean one thing….the start of bronchiolitis season.

 

Bottom Line

  • Bronchiolitis is a common lower respiratory tract illness in children under 2 years.
  • The natural course of bronchiolitis lasts 7-10 days, with day 2-3 being the most severe.
  • Be aware of the risk factors for severe bronchiolitis.
  • If the clinical picture and course doesn’t ‘fit the script’, reconsider the diagnosis.
  • Consider a broad range of differential diagnoses in a child presenting with increased work of breathing and fever.
  • Be aware of the ‘overlap’ between bronchiolitis/viral-induced wheeze and asthma.

 

What is it?

Bronchiolitis is, as the name suggests, inflammation of the small bronchi and bronchioles. The clinical entity we know as bronchiolitis is the most common admission diagnosis in patients under 2, accounting for high morbidity in this population. More succinctly;

“A seasonal viral illness characterized by fever, nasal discharge, and dry, wheezy cough. On examination, there are fine inspiratory crackles and/or high-pitched expiratory wheeze.” – The University of Nottingham, in their 2009 Acute Breathing Difficulty Guideline.

It is most often caused by respiratory syncytial virus (50-80%), as well as parainfluenza (especially PIV3), human metapneumovirus, influenza, rhinoviruses, and adenovirus. In the words of my first general paediatric consultant:

“Bronchiolitis is a typical winter illness, which almost every child gets in their first two years of life. What matters is first, how old you are when you get it, and secondly, what kind of condition you’re in.”

 

What are the clinical features?

Several days of upper respiratory tract symptoms, including fever, rhinorrhoea, and coryza. These develop into a wheeze, tachypnea, increased work of breathing, moist cough, and fevers. The increased work of breathing often leads to decreased oral intake, with or without dehydration. In infants, poor feeding and apneas with or without cyanosis may be present.

Auscultation of the lungs may reveal a wheeze and transmitted upper airway sounds. A focal zone with decreased air entry or coarse crackles is more consistent with pneumonia.

It is well described that a typical course of bronchiolitis lasts 7-10 days, with night 2-3 being the most severe. In this respect, it is important to reconsider the diagnosis in any patient not ‘sticking to the script’, or deteriorating after initial improvement. A cough may last for up to four weeks.

 

Diagnosis

The diagnosis is primarily clinical. Clinical features of an area of the lung with decreased air entry or consistent focal crackles warrant a chest radiograph to exclude pneumonia. A chest radiograph infrequently adds to the clinical picture and is not routine.

Some clinicians will obtain a nasopharyngeal aspirate or flocculated swab for respiratory virus PCR. There is also a rapid antigen test, which is good for ruling in, rather than ruling out, a particular virus.

Although typing of the respiratory virus causing bronchiolitis may be helpful for bed management and nursing, it is unlikely to alter management.

This point remains controversial as knowledge of the causative organism may allow some prognostication regarding illness course and prevent unnecessary antibiotic usage. It does not rule out dual respiratory tract pathology, such as secondary bacterial infection.

In particular, there is merit to obtaining swabs in patients with risk factors for severe infection, thus:

 

Risk Factors for Severe Infection

  • Age <1 yo, especially less than 6 weeks
  • Congenital heart disease
  • Neurological conditions
  • Chronic respiratory illness
  • Pulmonary hypertension
  • Ex-premature infants
  • Inborn errors of metabolism
  • Trisomy 21
  • Cystic fibrosis
  • Immunodeficiency
  • A previous severe bronchiolitis illness requiring CPAP or PICU admission.

 

Around 50% of children with severe infections have none of the above risk factors.

Children at risk of severe infection and mild symptoms should be admitted and observed.

As noted earlier, the course of the illness is that night 2-3 is usually the most severe, thus any child presenting earlier will potentially worsen, sometimes quite rapidly.

 

How do we manage it?

Management is supportive, with rehydration and fluid maintenance whilst unable to feed and respiratory support as required. If the child is unlikely to deteriorate and does not require inpatient observation or additional support, they can often be managed in the outpatient setting. It’s essential to provide clear safety-net advice for when to return to ED as well as strongly encouraging an early GP review.

 

Admit for observation

Infants <6/52 and patients with the risks for severe infection above are at risk of apnoeas, so cardiorespiratory monitoring is indicated. Oxygen saturation monitoring is indicated in all children. Keep a close eye on work of breathing and hydration as these can change as the illness progresses.

 

What level of oxygen saturation is acceptable?

There are differing opinions regarding target oxygen saturation in patients with bronchiolitis. Most would agree on a target somewhere between ≥94% and ≥92%. But which?

Consider the oxygen-haemoglobin dissociation curve:

 

 

Conditions that push the curve to the right (higher PO2 to maintain SaO2 and curve has a steeper gradient), are decreasing pH, increasing temperature.

Thus, in a febrile, acidotic child the curve is pushed to the right, requiring a higher PO2 to maintain the same level of saturation and thus increasing the likelihood of desaturations. In these children, aiming for an SaO2 of 94% would be reasonable. Local guidelines may have differing suggestions.

 

Respiratory support

Oxygen delivery can be via nasal cannulae, or if bronchiolitis severe by high-flow humidified oxygen via nasal prongs.  High-flow provides continuous positive airway pressure (CPAP) and aims to avoid intubation.

Flow rates of 2l/kg/min provide a PEEP of 4-8cm, improving the functional residual capacity.

In life-threatening cases, sedation, intubation and ventilation may be necessary and should be done with PICU and senior support. In regional and rural settings, it’s important to be aware of local limitations and consider early transfer to a tertiary centre for deteriorating, high-risk patients. For the care of such patients, make early contact with your regional Paediatric Emergency Transfer Services.

 

Hydration

Children with acute illness are susceptible to SIADH and hyponatremia. Thus, it’s important that whilst supporting the increased insensible losses and decreased intake as a result of respiratory distress we don’t over hydrate the patient. Around 2/3 maintenance for an infant not tolerating oral intake is sufficient to both hydrate and reduce the likelihood of SIADH. Most paediatric departments would use 0.9% saline and 5% dextrose.

In mild cases of bronchiolitis, small, frequent feeds may provide sufficient hydration. As respiratory distress increases, nasogastric feeds (continuous vs bolus) may be required. For a child with severe bronchiolitis, on high-flow nasal prongs or moderately dehydrated, intravenous therapy is indicated.

 

Other Therapies

Antibiotics are not indicated for bronchiolitis, nor is there a benefit in the use of steroids, nebulized adrenaline, or bronchodilators. Additionally, there is no benefit in physiotherapy or macrolide antibiotics.

Although salbutamol does not alter the clinical course of bronchiolitis, in the case of a strong family history of atopic disease or asthma it would not be unreasonable to trial a course of salbutamol, particularly in the child >6 yo who is presenting with a wheeze.

It’s important to assess the child pre- and post-salbutamol for both subjective and objective clinical response. This may also have some utility in differentiating between viral bronchitis and a viral-induced wheeze. Again, this is a controversial sub-topic with evolving evidence.

Bronchiolitis has a broad range of differential diagnoses; it is important to consider these, particularly if the patient is not responding as expected to your initial management, or if there are features of the history or examination of an alternative diagnosis.

 

What’s the differential?

Pneumonia or other pulmonary infections, including mycoplasma and pertussis – listen for focal crackles or signs, productive cough or radiological features of pneumonia. These patients will usually have a fever, in addition to cough and tachypnoea. Consider viral, bacterial, chlamydial or mycoplasma pneumonia. This is a common alternative diagnosis for bronchiolitis.

Recurrent viral-triggered wheezing – another common alternative diagnosis, viral-triggered wheeze may present quite similarly. Features in the history that might point you towards a viral-induced wheeze, is that of an antecedent URTI which had resolved, followed by wheeze and work of breathing a few days later, with or without fever. Differentiating between RSV bronchiolitis and a viral-induced wheeze can be particularly challenging.

Meningitis – most consultants can describe a patient who presents during a “bronchiolitis epidemic” who has meningitis. Always consider this differential diagnosis. Although it’s had to find case reports in the medical literature, unfortunately, the lay press has many examples of this.

Foreign body aspiration – characterized by rapid onset and failure of initial management. May have a low-grade fever. Have a high index of suspicion.

Croup – usually stridor rather than a wheeze, and with a similar gamut of causative organisms. Laryngotracheobronchitis can present with a wheeze in a child with bronchitic disease.

Aspiration pneumonia – consider more strongly in children with poor airway protection, including spastic cerebral palsy, or in any child having seizures or convulsions.

Gastro-oesophageal reflux – up to 40-50% of infants with GORD present with wheeze or respiratory symptoms. There is also an association with chronic cough.

Asthma – an acute exacerbation is less likely to have fevers, and will often have a personal history of atopy or allergy, or a family history of asthma. It would be rare to diagnose a child under two with asthma at a first presentation to the hospital with a wheeze.

Chronic pulmonary disease – chronic neonatal lung disease or prematurity predisposes the child to respiratory infections.

A mediastinal mass – there are multiple case reports of mediastinal masses presenting with a wheeze and respiratory distress.

Tracheoesophageal fistula – late-presentation of H-type tracheoesophageal fistula may present as coughing, abdominal distension, and recurrent chest infections. Sundar’s well described 1975 case series can be found here.

Congenital heart disease and heart failure – to be considered in any neonate presenting with increased work of breathing, with or without apneas. These patients will look unwell, with a constellation of symptoms including disproportionate tachycardia, poor perfusion with or without cyanosis, weak femoral pulses & murmurs.

Vascular ring, congenital lobar emphysema or a bronchogenic cyst  – may also present in neonates with a “bronchiolitis-sounding” history.

 

Selected references

Coffin. S,E., Bronchiolitis: In-Patient Focus, Pediatric Clinics of North America – Volume 52, Issue 4 (August 2005).

Grimes, A. All That Wheezes… HOSPITAL PEDIATRICS Vol. 2 No. 1 January 1, 2012 pp. 47 -50

Zorc, JJ & Breese Hall, C. Bronchiolitis: Recent Evidence on Diagnosis and Management. Pediatrics. Vol. 125 No. 2 February 1, 2010  pp. 342 -349 (doi: 10.1542/peds.2009-2092).

Marlais M, Evans J, Abrahamson E. Arch Dis Child 2011;96:648-652 doi:10.1136/adc.2010.201079 Clinical predictors of admission in infants with acute bronchiolitis.

Royal Children’s Hospital, Melbourne. Clinical practice guidelines : Bronchiolitis.

Paediatric Grand Rounds – Acute Viral Bronchiolitis in Children by Dr Nitin Kapur, Respiratory Paediatrican. Lecture on 5th June 2013 @ Royal Children’s Hospital, Herston QLD. Slides.

Fitzgerald, D.A. & Kilham, H.A., Bronchiolitis: assessment and evidence based management. MJA 2004; 180(8): 399-404.

Lakhanpaul M, Armon K, Eccleston P, et al. An Evidence Based Guideline for the Management of Children Presenting With Acute Breathing Difficulty. Nottingham, United Kingdom: University of Nottingham; 2002. 

Louie, M C & Bradin, S. Foreign Body Ingestion and Aspiration Pediatrics in Review August 2009; 30:295-301.

Sheikh S, Allen E, Shell R, Hruschak J, Iram D, Castile R, McCoy K. Chronic aspiration without gastroesophageal reflux as a cause of chronicrespiratory symptoms in neurologically normal infants. Chest. 2001 Oct;120(4):1190-5. PMID: 11591559.

Saglani, S., et al. Investigation of young children with severe recurrent wheeze: any clinical benefit? Eur Respir J 2006 27:29-35; doi:10.1183/09031936.06.00030605. 

Sheikh S, Stephen T, Howell L, Eid N. Gastroesophageal reflux in infants with wheezing. Pediatr Pulmonol. 1999 Sep;28(3):181-6. PMID: 10495334.

National Asthma Council Australia. Asthma Management Handbook 2006. Melbourne, 2006.

Heinz, P. & Dunne, J. Wheeze and mediastinal mass: A challenging patient. Emergency Medicine Vol 16(3)241-243, June 2004. DOI: 10.1111/j.1742-6723.2004.00573.

Sundar, B., Guiney, E.J. & O’Donnell, E. Congenital H-type tracheo-oesophageal fistula. Arch. Dis. Ch. 1975 (50)862. 

Hsu, D. & Pearson G., Heart Failure in Children. Part I: History, Etiology, and Pathophysiology. Circ Heart Fail 2009;2;63-70; DOI: 10.1161/CIRCHEARTFAILURE.108.820217.

Phelan, E., Ryan, S. & Rowley, H. Vascular rings and slings: interesting vascular anomalies. The Journal of Laryngology & Otology (2011), 125, 1158–1163.

Are nebulisers or spacers better for managing acute asthma?

Cite this article as:
Tessa Davis. Are nebulisers or spacers better for managing acute asthma?, Don't Forget the Bubbles, 2013. Available at:
https://doi.org/10.31440/DFTB.3278

This Cochrane review was published this week and here’s my summary.

This review looks at the question:

Which is better for the delivery of salbutamol in acute asthma – spacers or nebulisers?

The full version can be read here.

 

Why is this review useful?

It’s useful because, in my experience, different hospitals have different practices with regards to the initial management of asthma in PED. In my previous hospital we gave 3 back-to-back salbutamol nebulisers (2.5mg or 5mg depending on the age/size). In my current hospital we give 3 x 20 minutely salbutamol inhalers.

 

What type of patients were included?

The studies included children being managed in ED, or in the community, wih acute asthma.

People with life-threatening asthma were excluded.

 

How many patients were included?

This review looked at 39 studies which included 1897 children.  The review also looked at the evidence in adults.

 

What were the outcomes?

Primary outcomes: admission to hospital; duration of inpatient hospital stay.

Secondary outcomes: time in ED; change in respiratory rate; blood gases; pulse rate; tremor; symptom score; lung function; use of steroids; relapse rates.

 

What were the findings for these outcomes in ED?

There was no significant benefit in using nebulisers rather than spacers to deliver beta agonists to prevent hospital admission. And, the time spent in ED was significantly shorter (mean 33 mins) with spacers.

Pulse rate after treatment was significantly lower in children who received treatment via a spacer and development of tremor was more common in children who received nebulised treatment.

There was no difference in lung function or oxygen saturation.

 

Other points to note…

The authors acknowledge the uncertainty of choosing the correct dose.  The studies generally rely on titrating the treatment to the response of the patient and repeating doses as necessary.  This is good advice for real life.

The type of spacer did not affect the outcome.

The studies compared inhalers to separate nebulisers (not continuous). In practice, many hospitals use continuous nebulisers which is thought to be more effective than separate nebuliserss as it avoids rebound bronchoconstriction.

 

Main Conclusion

“Metered-dose inhalers with a spacer can perform at least as well as nebulisation in delivering beta-agonists in children with acute asthma”

Salbutamol has systemic side effects – tremor and increased pulse rate were more common when using nebulisers.

 

Intubation

Cite this article as:
Marc Anders. Intubation, Don't Forget the Bubbles, 2013. Available at:
https://doi.org/10.31440/DFTB.3880

Indication:

  • to secure the airway: severe airway obstruction/inadequate protective reflexes (coma or prolonged seizures)
  • to facilitate ventilation: hypoxaemic and/or hypercarbic respiratory failure

Intubation should NOT be attempted by the inexperienced if more skilled personnel are available. Two doctors always present if possible!


Assessment:

  • how urgent is the intubation?
  • anatomical abnormality, which would suggest difficult intubation?
  • any evidence of airway obstruction?
  • cardiovascular status – any hypovolaemia/hypotension?
  • is the patient fasted?

 Preparation equipment:

  • intubation drugs
  • volume replacement (10ml/kg NaCl 0.9%)
  • ETT (size = age/4 + 4 – for uncuffed ETT for cuffed ETT size = age/4 + 3.5), one size above and one size below calculated ETT
  • styllete, gum elastic bougie
  • laryngoscope with blade (check light bulb and battery)
  • Magill’s forceps
  • face mask
  • Guedel and nasopharyngeal airways
  • self inflating bag and anaesthetic circuit
  • suction equipment: Yankauer’s sucker and suction catheters
  • connector, cuff inflating syringe, tape
  • CO2 detector

Procedure:

  • monitor cardiovascular and respiratory status (ECG, SpO2, BP non-invasive/invasive)
  • explain to patient/parents
  • empty stomach if nasogastic tube is in situ
  • position patient: neutral position in neonates, young children – sniffing position in older children, adolescents
  • preoxygenation for minimum two minutes
  • consider atropine 20 mcg/kg IV
  • give analgesic agent
  • give sedative agent
  • apply gentle pressure to the cricoid
  • check for bag and mask ventilation possible with appropriate visual inflation/deflation and chest wall movement
  • give paralysis agent
  • continue bag and mask ventilation, while continuing to apply gentle cricoid pressure, except in circumstances where bag and mask ventilation is contraindicated (see rapid sequence induction)
  • intubate orally, release cricoid pressure
  • check ETT position: chest wall rise, auscultation and CO2 detector
  • once patient stabilised and appropriate ventilation, consider to change to a nasal ETT
  • once ETT position confirmed, tape ETT
  • insert nasogastric tube, empty stomach
  • CXR to confirm position of ETT and nasogastic tube
  • consider ongoing analgesia and sedation
  • document event

Intubation drugs:

see analgesia and sedation in PICU

Analgesia Sedation Paralysis
cardiovascular stable, no airway obstruction > 1 year

Fentanyl1 – 2mcg/kg

or

Morphine

100mcg/kg

Propofol1 – 2.5mg/kg Vecuronium 0.1mg/kg
cardiovascular stable, with airway obstruction > 1 year

Fentanyl1mcg/kg

or

Morphine

100mcg/kg

Ketamine1 – 2mg/kg Vecuronium 0.1mg/kg
cardiovascular stable, no airway obstruction < 1year

Fentanyl1 – 2mcg/kg

or

Morphine

100mcg/kg

Midazolam50 -100mcg/kg Vecuronium 0.1mg/kg
cardiovascular stable, with airway obstruction < 1 year Always seek senior assistance!Consider induction with volatile anaesthetic!
cardiovascular unstable, any age

Fentanyl1 – 2mcg/kg

or

Morphine

100mcg/kg

Vecuronium0.1mg/kg
rapid sequence induction

Fentanyl1 – 2mcg/kg

or

Morphine

100mcg/kg

Midazolam50 -100mcg/kg Rocuronium1mg/kg
patients with raised ICP

Fentanyl1 – 2mcg/kg

or

Morphine

100mcg/kg

Thiopentone2 – 7mg/kg Rocuronium1mg/kg
anticipated difficult airway Always seek senior assistance!Consider induction with volatile anaesthetic!

 


Unexpected difficult intubation:

  • call for help!
  • restart bag and mask ventilation with gentle cricoid pressure
  • optimise patient position
  • consider bougie or stylete
  • consider different laryngoscope blade

Cannot ventilate – cannot intubate:

  • call for help!
  • consider reposition of head
  • jaw thrust
  • insert Guedel/nasopharyngeal airway
  • use both hands to hold mask
  • release cricoid pressure
  • consider laryngeal mask (LMA)

    All Marc’s PICU cardiology FOAM can be found on PICU Doctor and can be downloaded as a handy app for free on iPhone or AndroidA list of contributors can be seen here.