Respiratory Distress in Children

Question 1

Intro

Answer 1

Respiratory disease is the most common reason for acute hospital
admission in children,

Often call put out - The child has deteriorated significantly and usually requires
non-invasive or invasive ventilation and transfer to a paediatric ICU (PICU)

Question 2

Key points

Answer 2

1 Many paediatric emergencies result from
severe respiratory distress or
imminent respiratory failure.

2 Common causes of paediatric respiratory distress
include
bronchiolitis,
wheeze in the preschool child,
asthma
and pneumonia.

3 Less common causes
include interstitial lung disease,
pulmonary aspiration
and
problems associated with tracheostomies.

4 Signs of impending respiratory failure warrant
involvement of an anaesthetist and,
in most cases,
tracheal intubation and artificial ventilation.

5 Management of paediatric respiratory distress
requires meticulous preparation to avoid complications
during induction of anaesthesia, intubation and ventilation.

Question 3

Common causes of paediatric respiratory distress
include

Answer 3

Bronchoconstriction and wheezing

bronchiolitis,

asthma

and

pneumonia.

Interstitial lung disease,
pulmonary aspiration
and
problems associated with tracheostomies

Question 4

Bronchoconstriction and wheezing

Incidence and deaths 2016

Pathophys

Answer 4

1 in 11 children

12 deaths in uk 2016

Not fully understood:
variable airflow obstruction
and airway hyper-reactivity involved

Exacerbation
Infective + Non

viral infection

Question 5

Wheeze Rx Algorithim

Answer 5

(i) Oxygen

(method dependent on severity:
low-flow nasal cannulae,
Hudson face mask,
or high-flow nasal
cannulae)

(ii) Nebulised b2-agonists
with the addition of an inhaled
anticholinergic if response is poor

(iii) Corticosteroids
(i.v. route likely to be required in severe respiratory distress)

(iv) Magnesium sulphate, salbutamol, and aminophylline
(i.v. infusions as required)

Question 6

Signs of impending respiratory collapse

Answer 6

1 Exhaustion:
evidenced by listlessness or
decreased respiratory effort

2 Cyanosis

3 Impairment of consciousness

4 SpO2 <92% despite supplemental oxygen FIO2 0.6

5 Recurrent apnoea

6 Worsening hypercarbia

Question 7

Rx explained

Fastest?

Poor response to ventilation?

Does this fix problem?

NIV?

Answer 7

Of these treatments,

there is some evidence that magnesium sulphate works the fastest,
and it should, therefore, be
the first choice in patients requiring i.v. treatment

Where there is poor response,
artificial ventilation must be considered.

In the child in whom medical management is failing,
mechanical ventilation must be considered,

although it must be noted that this alone does not correct the underlying
problem, and these children can be very difficult to manage
after tracheal intubation

Non-invasive ventilation is used in
some centres. At present, there is no clear evidence of its
effectiveness in avoiding intubation.3

However, a 2016 Cochrane review concluded that there was also no evidence of harm

Question 8

Dx asthma

Answer 8

Because of the high incidence of wheezing syndromes in
those children aged <6 yrs, asthma is not ordinarily diagnosed
before this, when more common causes of wheezing include
bronchiolitis and ‘preschool wheeze’.

Question 9

Dx asthma

Answer 9

Because of the high incidence of wheezing syndromes in
those children aged <6 yrs, asthma is not ordinarily diagnosed
before this, when more common causes of wheezing include
bronchiolitis and ‘preschool wheeze’.

Question 10

Commonest disease 1st year life

Answer 10

Bronchiolitis is the most common disease of the lower respiratory
tract in the first year of life,

affecting approximately one in three infants.

Overall, 2-3% of cases require hospitalisation.6

It is most commonly caused by respiratory syncytial virus,
but other viruses are also implicated.
-Rhinovirus
- influenza

Question 10

Commonest disease 1st year life

affects what %

How many need hospital

Causes

Answer 10

Bronchiolitis is the most common disease of the lower respiratory
tract in the first year of life,

affecting approximately one in three infants.

Overall, 2-3% of cases require hospitalisation.6

It is most commonly caused by respiratory syncytial virus,
but other viruses are also implicated.
-Rhinovirus
- influenza

Question 11

Pathophysiology bronchiolitis

Answer 11

Infection of the epithelial cells
of the small airways causes inflammation,
mucous production,
and sloughing of necrotic epithelial cells leading

to obstruction of the small airways with resulting
hyperinflation,
atelectasis,
and wheeze

Question 12

Bronchiolitis
Presentation

Answer 12

Presentation is with
coryzal symptoms followed
by tachypnoea,
cough, crackles or wheeze;

apnoea is more common in babies less than 6 weeks old.

The prognosis is
good and mortality is rare.

Question 13

Risk factors for severe Bronchiolitis

Answer 13

Risk factors for severe illness are prematurity

(especially those babies born at <32 weeks gestational age),

bronchopulmonary dysplasia,

congenital heart disease,

neuromuscular diseases,

immunodeficiency,

and age <3 months

Question 14

Bronchiolitis Rx

Answer 14

1. The initial treatment is suctioning the nostrils,
2. supplemental oxygen if SpO2 persistently is less than 92%,
3. and nasogastric (NG) feeding
   (which will be stopped in cases of severe respiratory distress).
4. Chest physiotherapy,
   nebulisers,
   antibiotics,
   and steroids

are not included in the
current guidelines because of a lack of evidence

However, in
the context of progressive deterioration, these measures may
be considered to avoid invasive ventilation.

5. CPAP should be commenced if there are signs of impending respiratory failure

Some units use high-flow oxygen therapy (HFOT)
via nasal cannulae instead of CPAP.

A recent multicentre trial comparing conventional nasal oxygen therapy with HFOT showed that treatment failure requiring escalation of care
occurred less frequently in the HFOT group (12% vs 23%)

Question 15

‘preschool wheeze’
Descrbies

what age
% continuie to wheeze?

Admission?
Rx
Try?

Answer 15

The term ‘preschool wheeze’ is used to describe several
clinical syndromes, some of which are overlapping.

Most cases are transient with only 15% continuing to wheeze
after 6 yrs of age.

The vast majority of these episodes are managed at
home or in primary care,

but children may present with this
history before surgery,

so awareness of the condition is important.

If a child is unwell enough with preschool wheeze
to be admitted to a hospital,

treatment includes
supplemental oxygen,
inhaled bronchodilators and
oral corticosteroids.

In cases with poor response, the following can be considered,
but have equivocal or no evidence of efficacy:
inhaled corticosteroids,
leukotriene antagonists,
antihistamines and i.v. bronchodilators

Question 16

Pneumonia

Incidence

Prevelance by age group

How present

Rx

Improbement

What concern lack improvement / persistent fever

Answer 16

The incidence of pneumonia in children is 14.4 per 10,000.

It affects all age groups,
and can be bacterial,
viral, or mixed.

In those children aged <2 yrs,

the ratio of viral:bacterial causes is 50:50,

whereas in older children bacterial pneumonia becomes more common,

with pneumococcus being the most common organism.

Patients present with a history and signs
indicating respiratory distress and fever.

Treatment is supportive with supplemental oxygen
and appropriate antimicrobials.

Improvement is usually rapid,

Question 16

What concern lack improvement or persistent fever

how often occur

What organism cause complication or likely picu

Prognosis
Where does it rank cause paed mortality

how compare w/ meningitis in high income

Answer 16

and a lack of improvement
within 48 h
or
persistent fever >38C

should prompt a reassessment for complications,

such as lung abscesses,
pleural effusion,
empyema -

which occur in 1% of cases overall,
but in 40% of cases admitted to a hospital.

Infection with
group A streptococcus
and
Staphylococcus aureus
is most likely to progress to these
complications or require admission to PICU.

The prognosis is generally very
good in high-income countries,
but it should be noted that
pneumonia is the leading infectious cause of paediatric mortality worldwide;

in high-income countries, pneumonia kills
3,000 children per year compared with meningitis,
which kills 640 children per year

Question 17

Chronic aspiration

Causes

Undx - consequence

NM disease/

Rx

Answer 17

Chronic aspiration is a
frequent underlying cause of recurrent pneumonia
and can be difficult to diagnose.

There are many potential causes,
including
undiagnosed tracheooesophageal fistula,
laryngeal cleft,
craniofacial abnormalities,
gastro-oesophageal reflux disease,
and neuromuscular diseases (including bulbar palsy).

If undiagnosed or untreated,
recurrent pneumonia will lead to chronic lung disease (CLD)

with the development of bronchiectasis
and progressive respiratory failure.

Chronic aspiration is the leading cause of
death in children with neuromuscular disease.

Treatment is supportive during acute episodes of infection
with supplemental oxygen and appropriate,
targeted antimicrobials.

Prevention of recurrent episodes relies on identifying the
underlying cause and correcting it where possible.11

Question 18

Sepsis

Answer 18

It should be remembered that respiratory distress can be a
sign of non-respiratory sepsis. In addition, children presenting with decompensated congenital heart disease are likely to
be in respiratory distress. Therefore, a thorough assessment
of all systems in all children is vital.

Question 19

Chronic lung disease

Answer 19

Chronic lung disease

Children’s interstitial lung disease (chILD)
describes a widely varied and poorly understood
group of chronic respiratory disorders in children,
with an incidence in the region of 0.36 per 100,000.

It represents a group of diseases with varying
pathophysiologies that are beyond the scope of this article.

The patterns of the disease can be either obstructive or
restrictive, or both, depending on the cause,
and all may be complicated by superimposed infection.

Morbidity and mortality are high with an overall mortality of 30%
for which the development of pulmonary hypertension
is an independent risk factor.12

Chronic lung disease of prematurity, previously
termed bronchopulmonary dysplasia,

is the most common chILD diagnosis,
affecting 20% of neonates born at <30 weeks
gestational age with birth weight <1.5 kg.

With improved survival of babies born at the limits of viability with extremely
low birth weights, children with CLD present frequently to a
hospital with respiratory difficulty, which may result from
infection or chronic aspiration.13

Question 19

Chronic lung disease

Answer 19

Chronic lung disease

Children’s interstitial lung disease (chILD)
describes a widely varied and poorly understood
group of chronic respiratory disorders in children,
with an incidence in the region of 0.36 per 100,000.

It represents a group of diseases with varying
pathophysiologies that are beyond the scope of this article.

The patterns of the disease can be either obstructive or
restrictive, or both, depending on the cause,
and all may be complicated by superimposed infection.

Morbidity and mortality are high with an overall mortality of 30%
for which the development of pulmonary hypertension
is an independent risk factor.12

Chronic lung disease of prematurity, previously
termed bronchopulmonary dysplasia,

is the most common chILD diagnosis,
affecting 20% of neonates born at <30 weeks
gestational age with birth weight <1.5 kg.

With improved survival of babies born at the limits of viability with extremely
low birth weights, children with CLD present frequently to a
hospital with respiratory difficulty, which may result from
infection or chronic aspiration.13

Question 20

Patients with a tracheostomy

Answer 20

Patients with a tracheostomy

Tracheostomy is being performed
increasingly in children,
with an ever-increasing number of patients being cared for at
home.

Indications for tracheostomy are wide ranging and
include
neuromuscular disease;
respiratory disease;
congenital malformations of airway,
lungs, or heart;
craniofacial syndromes;
and acquired subglottic stenosis.14

It follows that we can expect to see an
increasing number of paediatric patients with a
tracheostomy presenting in respiratory distress
to emergency departments.

Perhaps more importantly in the
case of patients with a tracheostomy,
it must be remembered that this may
be caused by airway obstruction
or tracheostomy problems,

such as a large leak, as opposed to, or as well
as, primary lung pathology.

It has been reported that 43% of
patients will have a serious complication
with their tracheostomy, and mortality related
to tracheostomy complications
is 0.7%.

Question 21

Emergency management of paediatric
respiratory distress: when, who, and how to
intubate

Answer 21

There are no evidence-based guidelines on the optimal
timing of tracheal intubation in cases of respiratory distress.

The general approach to the assessment and
management of a child in respiratory distress
will be discussed in the following paragraphs and boxes, followed by
disease-specific alterations to this approach that may be
considered

Question 22

Emergency management of paediatric
respiratory distress: when, who, and how to
intubate

Answer 22

There are no evidence-based guidelines on the optimal
timing of tracheal intubation in cases of respiratory distress.

The general approach to the assessment and
management of a child in respiratory distress
will be discussed in the following paragraphs and boxes, followed by
disease-specific alterations to this approach that may be
considered

Question 23

Assessment

Answer 23

Assessment

Assessment should be largely clinical,
as the signs of impending respiratory failure
or severe respiratory distress should be identifiable
without the need for blood gas analysis,

and should prompt an intervention either non-invasive
or invasive ventilation.

Beware of children with myopathy,
as they are unable to demonstrate signs of
increased work of breathing.

Box 1 details the signs of impending respiratory
collapse

Question 24

Assessment

Answer 24

Assessment

Assessment should be largely clinical,
as the signs of impending respiratory failure
or severe respiratory distress should be identifiable
without the need for blood gas analysis,

and should prompt an intervention either non-invasive
or invasive ventilation.

Beware of children with myopathy,
as they are unable to demonstrate signs of
increased work of breathing.

Box 1 details the signs of impending respiratory
collapse

Question 25

Signs of impending respiratory collapse

Answer 25

Signs of impending respiratory collapse
Exhaustion: evidenced by listlessness or decreased
respiratory effort
Cyanosis
Impairment of consciousness
SpO2 <92% despite supplemental oxygen FIO2 0.6
Recurrent apnoea
Worsening hypercarbia

Question 26

General approach

Answer 26

Conduct of the intubation must be determined on a case-by case basis,

looking at the cause of respiratory distress,
predicted airway difficulty,
equipment and available personnel,
and risk of aspiration.

Monitoring, including end-tidal carbon
dioxide (CO2), should be prepared in advance.

Thought must be given to the most
appropriate person to lead the induction
and intubation, and senior help is called where necessary.

Emergency drugs should be prepared in advance in the correct
dose for the patient,
and these drugs include
atropine and
suxamethonium with the addition of
adrenaline (epinephrine) if the patient is haemodynamically compromised.

Prepare a 10-20 ml kg i.v. fluid bolus in advance.

Induction of anaesthesia in an unstable child
almost always mandates having secured i.v. access,
but intraosseous access should not
be overlooked if i.v. access fails.

Question 27

Drugs for induction

Answer 27

Consideration should be given to the correct drug for induction of anaesthesia. Ketamine confers the benefits of
bronchodilatation and relative cardiovascular stability over
propofol, the dose of which must be reduced in the haemodynamically compromised or septic child. Thiopental can
cause bronchoconstriction and so is a poor choice in a child
with obstructive respiratory disease. Inhalation induction
with sevoflurane is an option if scavenging is available; sevoflurane also results in bronchodilatation. Neuromuscular
block will provide optimal intubating conditions in most
cases: rocuronium, suxamethonium, or atracurium is used.
The choice of agent can be based on familiarity of the operator. However, it should be noted that atracurium can precipitate histamine release and may therefore worsen
bronchoconstriction. Similarly, the addition of fentanyl will
help provide optimal intubating conditions.

Question 28

Blades and tubes

Sizes for Tubes

Depth

Answer 28

Straight laryngoscope blades are generally used in babies
up to 6 months and curved blades thereafter.

Sizes for cuffed TT:
>3 kg up to 1 yr: start with size 3.0 mm

1-2 yrs: start with size 3.5 mm

> 2 yrs: (age/4) +3.5 mm

___________________________________

Size for uncuffed TT:
<1 yr: 1 kg: size 2.5 mm

2 kg: size 3.0 mm

> 1 yr (age/4)+4 mm

Depth:
(Age/2)+12 cm

Tip of ETT should lie at mid-trachea

Question 28

Blades and tubes

Sizes for Tubes

Depth

Answer 28

Straight laryngoscope blades are generally used in babies
up to 6 months and curved blades thereafter.

Sizes for cuffed TT:
>3 kg up to 1 yr: start with size 3.0 mm

1-2 yrs: start with size 3.5 mm

> 2 yrs: (age/4) +3.5 mm

___________________________________

Size for uncuffed TT:
<1 yr: 1 kg: size 2.5 mm

2 kg: size 3.0 mm

> 1 yr (age/4)+4 mm

Depth:
(Age/2)+12 cm

Tip of ETT should lie at mid-trachea

Question 29

Cuff ETT?

Answer 29

A cuffed TT is preferable to an uncuffed TT
particularly in disease states with high resistance,

such as asthma, where high ventilatory pressures will need to be
delivered over a prolonged period. Cuff pressure must be
monitored.
The practice of cutting the TT runs the risk of the
tube being too short,
requiring reintubation in a critically ill child.

Question 30

With regard to rapid sequence induction (RSI)

Answer 30

With regard to rapid sequence induction (RSI) in this setting,

it must be remembered that the priority is supporting

oxygenation and haemodynamic stability
whilst securing the airway.

The incidence of aspiration in paediatric practice is
extremely low.

Some would argue an RSI increases the risks
of haemodynamic instability, hypoxia and awareness.
Risk assessment must be performed on a case-by-case basis,
but some would argue that RSI has no place in paediatric practice.18

Question 31

Pre O2

Desat time?

Answer 31

Preoxygenation of the lungs is invaluable if it can be achieved.

It may be most appropriate to continue the mode of
delivery of oxygen currently in place in settled children, as

disturbing them with a tight-fitting face mask may cause
distress and increased work of breathing and oxygen demand.

In view of the potential inability to preoxygenate,
increased oxygen consumption,
and closing capacity in small children,
the length of apnoea time tolerated before desaturation is low

Oxygenation must remain the priority, and most would
advocate continued gentle mask ventilation whilst waiting for
adequate neuromuscular block regardless of fasting status.18

In adult practice, the introduction of transnasal humidified
rapid-insufflation ventilatory exchange (THRIVE) using highflow nasal cannulae during apnoea has allowed a significant
increase in apnoea times before oxygen desaturation. THRIVE
is beginning to be used in paediatric practice with promising
results in case reports, and so is an option to prolong apnoea
time in carefully selected paediatric patients if equipment is
available.

Question 31

Pre O2

Desat time?

Answer 31

Preoxygenation of the lungs is invaluable if it can be achieved.

It may be most appropriate to continue the mode of
delivery of oxygen currently in place in settled children, as

disturbing them with a tight-fitting face mask may cause
distress and increased work of breathing and oxygen demand.

In view of the potential inability to preoxygenate,
increased oxygen consumption,
and closing capacity in small children,
the length of apnoea time tolerated before desaturation is low

Oxygenation must remain the priority, and most would
advocate continued gentle mask ventilation whilst waiting for
adequate neuromuscular block regardless of fasting status.18

In adult practice, the introduction of transnasal humidified
rapid-insufflation ventilatory exchange (THRIVE) using highflow nasal cannulae during apnoea has allowed a significant
increase in apnoea times before oxygen desaturation. THRIVE
is beginning to be used in paediatric practice with promising
results in case reports, and so is an option to prolong apnoea
time in carefully selected paediatric patients if equipment is
available.

Question 32

Post-intubation care

Answer 32

The specific details of care after intubation are determined on
a case-by-case basis, but the following points must be
considered:

(i) Sedation and neuromuscular block:
midazolam and morphine are commonly used in combination with
either vecuronium or atracurium.
Fentanyl and ketamine are suitable alternatives.

Propofol is avoided in some centres,
except in short-term sedation, because of
the risk of propofol-related infusion syndrome.
The evidence for this is inconclusive
20; local guidelines should be followed.

(ii) NG tube insertion to
relieve gastric insufflation and
consequently reduce airway pressures

(iii) Chest X-ray: to check the position of the TT;
exclude endobronchial intubation or an inadequately advanced
TT that may migrate out during transfers;
to rule out pneumothorax,
which is a particular risk in bronchoconstriction
requiring invasive ventilation

(iv) Ventilation strategy:
there is a much smaller evidence
base for specific ventilation strategies
compared with adults,

but the trend is towards a ‘lung-protective’
strategy with the aim of achieving adequate
gas exchange at the lowest possible
pressures and volumes to
avoid alveolar trauma secondary to stretching.

Question 33

Ventilation

Therefore, the following general principles are advised:

Answer 33

(a) Tidal volumes of 5e7 ml kg1

(b) Plateau pressure of <30 cmH2O

(c) Peak inspiratory pressures of <35 cmH2O

(d) PEEP 5-7 cmH2O

(e) I:E ratio of 1:2 in most cases
(see section ‘Bronchoconstriction’ for further information on this)

(f) SpO2 >91-92%
(with the exception of patients with pulmonary hypertension
and brain injury in whom SpO2 should be kept >94%)

(g) Ventilatory frequency dependent on age of patient and
balance between avoiding barotrauma, yet achieving an
adequate minute ventilation

(h) Regular chest physiotherapy and suctioning

(i) Transfer of patient to PICU:
if this involves interhospital
transfer, this would be done by a local specialist retrieval
service who should be contacted early to facilitate
planning.

Question 34

Bronchoconstriction

Answer 34

The aforementioned general approach may need to be modified
in patients with asthma or other pathologies,

in which bronchoconstriction can occur,
including bronchiolitis,
preschool wheeze and chILD.

Ketamine should be considered as an i.v. induction agent
because of its direct effects causing bronchodilation.

However, it should be remembered that ketamine
may also increase respiratory secretion load, and
therefore, treatment with an anticholinergic may be useful
(e.g. atropine 20 mg k , maximum 600 mg,
or glycopyrrolate
4-8 m kg , maximum 200 mg in <12 yrs and 400 mg in >12 yrs).

A cuffed TT is essential in these diseases because of the
need for high airway pressures to achieve oxygenation and
ventilation.16

Question 35

Ventilation in Asthma

Problems

How can this be detected

What can this problem lead to

Answer 35

High airway resistance and therefore slow
expiratory flow can lead to incomplete exhalation,

which increases the end-expiratory volume
and leads to the development of intrinsic PEEP.

Intrinsic PEEP can be identified using
an end-expiratory breath-hold manoeuvre on the ventilator.

The value at which the pressure settles is the intrinsic PEEP.

The addition of further extrinsic PEEP
set on the ventilator to this,
with an expiratory time that is too short,
can lead to breath stacking
and further expansion of the alveoli
leading to
volutrauma,
CO2 retention
and pneumothorax.

Question 35

Ventilation in Asthma

Problems

How can this be detected

What can this problem lead to

Answer 35

High airway resistance and therefore slow
expiratory flow can lead to incomplete exhalation,

which increases the end-expiratory volume
and leads to the development of intrinsic PEEP.

Intrinsic PEEP can be identified using
an end-expiratory breath-hold manoeuvre on the ventilator.

The value at which the pressure settles is the intrinsic PEEP.

The addition of further extrinsic PEEP
set on the ventilator to this,
with an expiratory time that is too short,
can lead to breath stacking
and further expansion of the alveoli
leading to
volutrauma,
CO2 retention
and pneumothorax.

Question 36

The recommended principles for
ventilation of a patient with bronchoconstriction
are a

Answer 36

The recommended principles for
ventilation of a patient with bronchoconstriction
are a

1. low ventilatory frequency,
2. extended expiratory time to
   allow for complete expiration
   (observe for cessation of flow
   on the flow/volume loop before inspiration
   and set I:E ratio accordingly),
3. and a low extrinsic PEEP
   that does not exceed intrinsic PEEP.22

In the authors’ local PICU, a value of 60% of the
intrinsic PEEP is commonly used as a starting point.

4. Neuromuscular blocking agents are almost
   invariably required to achieve adequate oxygenation and
   ventilation.
5. The aforementioned ventilator settings may not allow for
   the removal of enough CO2 to maintain normocapnia.
6. Permissive hypercapnia allows oxygenation whilst reducing
   the risk of ventilator-associated lung injury
   caused by excessive pressure or
   volumes needed to maintain normocapnia.

There is no firm consensus on how low to allow the pH to go,
but a range of pH 7.15-7.3 was recently recommended by a
panel of experts.

7. However, it should be noted that patients
   with intracerebral pathology, severe pulmonary hypertension,
   and significant ventricular dysfunction are not
   appropriate candidates for this technique

Question 37

The recommended principles for
ventilation of a patient with bronchoconstriction
are a

Answer 37

The recommended principles for
ventilation of a patient with bronchoconstriction
are a

1. low ventilatory frequency,
2. extended expiratory time to
   allow for complete expiration
   (observe for cessation of flow
   on the flow/volume loop before inspiration
   and set I:E ratio accordingly),
3. and a low extrinsic PEEP
   that does not exceed intrinsic PEEP.22

In the authors’ local PICU, a value of 60% of the
intrinsic PEEP is commonly used as a starting point.

4. Neuromuscular blocking agents are almost
   invariably required to achieve adequate oxygenation and
   ventilation.
5. The aforementioned ventilator settings may not allow for
   the removal of enough CO2 to maintain normocapnia.
6. Permissive hypercapnia allows oxygenation whilst reducing
   the risk of ventilator-associated lung injury
   caused by excessive pressure or
   volumes needed to maintain normocapnia.

There is no firm consensus on how low to allow the pH to go,
but a range of pH 7.15-7.3 was recently recommended by a
panel of experts.

7. However, it should be noted that patients
   with intracerebral pathology, severe pulmonary hypertension,
   and significant ventricular dysfunction are not
   appropriate candidates for this technique

Question 38

Ventilating patients with bronchoconstriction - deterioration

Answer 38

Pneumothorax must be considered if there is any deterioration

in gas exchange or cardiovascular function.

The incidence of pneumothorax in patients with asthma requiring
mechanical ventilation is approximately 1-3%.

Pharmacological therapy with i.v. bronchodilators
(salbutamol or aminophylline)
to treat bronchoconstriction must continue,

as without it ventilation will deteriorate.

In patients whose lungs are difficult to ventilate adequately,
sevoflurane can be considered if scavenging is available.3

Question 38

Ventilating patients with bronchoconstriction - deterioration

Answer 38

Pneumothorax must be considered if there is any deterioration

in gas exchange or cardiovascular function.

The incidence of pneumothorax in patients with asthma requiring
mechanical ventilation is approximately 1-3%.

Pharmacological therapy with i.v. bronchodilators
(salbutamol or aminophylline)
to treat bronchoconstriction must continue,

as without it ventilation will deteriorate.

In patients whose lungs are difficult to ventilate adequately,
sevoflurane can be considered if scavenging is available.3

Question 39

Pneumonia and sepsis

Answer 39

The conduct of induction of anaesthesia, tracheal intubation,
and mechanical ventilation should be largely the same in
patients with pneumonia.

However, it should be noted that, if
there are signs of sepsis,

the dose of induction agent will need
to be reduced to prevent a precipitant decrease in arterial blood pressure.

Moreover, if there are already signs of circulatory compromise,
ensure adequate volume resuscitation,
calculate and prepare inotropic agents and vasopressors,
and consider starting these before induction of anaesthesia.

Postintubation care in cases of pneumonia will need to include
regular suctioning and chest physiotherapy.

Question 40

Patients with a tracheostomy in respiratory distress

Answer 40

The initial assessment of a patient with a tracheostomy in
respiratory distress must include a thorough assessment of
the patency of the tracheostomy.

The UK National Tracheostomy Safety Project has outlined an emergency algorithm for this purpose (Fig. 1).

After confirmation of the tracheostomy’s patency,
if the patient requires positive pressure ventilation,

then it may be necessary to upsize or
change the tracheostomy tube to a cuffed tube to facilitate this.

The management of patients with respiratory distress
is otherwise largely
similar to those patients without tracheostomy.

It should be remembered that they often have a complex medical background, and therefore, the threshold for ventilatory support
may be different to the child who is previously fit.

Further discussion of this is outside the scope of this article.

Question 41

Additional strategies to improve gas exchange

Answer 41

In the event of failure of oxygenation
despite best-practice ventilation,
several other strategies may be considered.

The evidence base for all is small,
although research is ongoing.

A survey conducted in 2013 showed that,
despite a lack of strong evidence,
the following techniques are considered and used in
many centres across North America and Europe, and they are
therefore relevant to current PICU practice.

High-frequency oscillatory ventilation (HFOV) was recently
recommended as an alternative strategy in a consensus paper
from the Pediatric Acute Lung Injury Consensus Conference in
patients with plateau pressures greater than 28 cmH2O.

It should be noted that, although there is some evidence that
supports a reduction in time on ventilator in paediatric patients,
there is none to support a mortality benefit

Inhaled nitric oxide has been used in neonatal practice for
many years,
but there is as yet no evidence to support a
mortality benefit in paediatric practice.

The mechanism of action is thought to be an improvement of oxygenation via
pulmonary vasodilation and improved ventilation/perfusion mismatch.

A recent study showed a quicker time to cessation
of mechanical ventilation and avoidance of other interventions,
such as HFOV and extracorporeal membrane
oxygenation (ECMO),
when hypoxia had responded to inhaled
nitric oxide

Question 41

Additional strategies to improve gas exchange

Answer 41

In the event of failure of oxygenation
despite best-practice ventilation,
several other strategies may be considered.

The evidence base for all is small,
although research is ongoing.

A survey conducted in 2013 showed that,
despite a lack of strong evidence,
the following techniques are considered and used in
many centres across North America and Europe, and they are
therefore relevant to current PICU practice.

High-frequency oscillatory ventilation (HFOV) was recently
recommended as an alternative strategy in a consensus paper
from the Pediatric Acute Lung Injury Consensus Conference in
patients with plateau pressures greater than 28 cmH2O.

It should be noted that, although there is some evidence that
supports a reduction in time on ventilator in paediatric patients,
there is none to support a mortality benefit

Inhaled nitric oxide has been used in neonatal practice for
many years,
but there is as yet no evidence to support a
mortality benefit in paediatric practice.

The mechanism of action is thought to be an improvement of oxygenation via
pulmonary vasodilation and improved ventilation/perfusion mismatch.

A recent study showed a quicker time to cessation
of mechanical ventilation and avoidance of other interventions,
such as HFOV and extracorporeal membrane
oxygenation (ECMO),
when hypoxia had responded to inhaled
nitric oxide

Question 42

Other strategies for hypoxia

prone

Answer 42

Prone positioning is one option that can be considered. It
has been shown to decrease mortality in adult patients with
acute respiratory distress syndrome,
but this is yet to be shown in paediatrics.

The mechanism of action is thought to

be recruitment of previously collapsed dorsal (dependent)
areas of lung and subsequent improvement in ventilation/ perfusion matching.26

Before using this technique, the potential haemodynamic effects
of the prone position,
potentially catastrophic loss of a secured airway, and any predicted
difficulty in securing the airway whilst maintaining oxygenation must all be considered.

Question 43

ECMO

Answer 43

Extracorporeal membrane oxygenation is considered in
cases where there is borderline or inadequate gas exchange
with high risk of ventilator-induced lung injury
(mean airway pressure >20-25 cmH20)
and continued severe respiratory failure
(PaO2:FIO2 ratio <60-80 or oxygen index >40)

despite less invasive therapies, such as those therapies mentioned
previously.

It has been shown to confer a survival advantage
in neonates with respiratory failure,
and remains an option in paediatric respiratory failure.

Presently, there is no evidence
of a survival benefit, and a recent small paired cohort study
confirmed this and highlighted the need for further research
into the benefits of ECMO, which remains an expensive and
invasive treatment option

Question 44

Conclusions

Answer 44

Respiratory distress is a common reason to alert the paediatric emergency response team or request input from
anaesthetists in the hospital setting.

This article has examined some of the more common causes of respiratory
distress (bronchiolitis, preschool wheeze and asthma) along
with rare, but commonly limiting illnesses, such as chILD.

It
should be remembered that respiratory distress can also
have extrapulmonary causes,
such as sepsis (with a source
other than pulmonary) and heart disease.

Management by
the anaesthetist requires meticulous and methodical planning of induction, intubation and ventilation to avoid complications thereof.

Senior help is always advised when
dealing with these patients. Patients with tracheostomies in
respiratory distress represent a special group in whom a
careful assessment of tracheostomy patency is the key, in
addition to the standard general approach, to paediatric
respiratory distress.

Question 45

trachy algorithm kids

Answer 45