Download Conscious sedation in children

Conscious sedation in children
Michael Sury FRCA PhD
Matrix reference 2D06, 3A07, 3D00
Key points
Effective sedation
techniques are specific to
the procedure.
Conscious sedation in
children can be
time-consuming but may
save anaesthesia resources.
Most effective techniques
risk deep sedation,
sometimes after the
procedure is completed.
Sedation failure and
complications can be
prevented by careful patient
assessment.
Training of healthcare
practitioners is crucial to
minimizing patient harm or
distress.
This article summarizes the principles and
practice of effective conscious sedation techniques for common diagnostic and therapeutic
procedures in children. It does not cover
sedation for intensive care or anxiolytic
premedication before anaesthesia.
Given that a conscious patient can independently maintain a clear airway and adequate
breathing, conscious sedation is safe because
the patient remains conscious. Safety of any
sedation technique is dependent upon the
ability of practitioners to prevent or safely
manage deeper levels of sedation.
Definitions
Consciousness is a continuum in which levels can
be recognized. Levels of sedation have been
defined by the ASA and they are widely accepted
(Table 1). In addition, the term ‘conscious’ sedation has remained in the UK. It is similar to
‘moderate’ sedation except that the patient always
remains responsive to the spoken word; this definition is used most commonly in dentistry.
Conscious sedation
Conscious sedation is defined in Box 1.1 There
is a difference between ‘conscious’ and ‘moderate’ sedation, but the terms are close enough
to make it reasonable to consider them to be
equivalent in this article. Ideally, a conscious
sedation drug technique should have a margin
of safety wide enough to make loss of consciousness unlikely.
Michael Sury FRCA PhD
Consultant Paediatric Anaesthetist
Department of Anaesthesia
Great Ormond Street Hospital for
Children NHS Trust
40 Bernard Street
London WC1N 3JH
UK
and
Portex Department of Anaesthesia
Institute of Child Health
University College London
London WC1N 1EH
UK
Tel: þ44 207 829 8865
Fax: þ44 207 829 8866
E-mail: [email protected]
(for correspondence)
152
Box 1
Conscious sedation is defined as:
Drug-induced depression of consciousness,
similar to moderate sedation, except that
verbal contact is always maintained with the
patient.
Specialist sedation techniques
Recently, it has been acknowledged that conscious sedation can be achieved reliably using
techniques that have a reduced margin of
safety.2 These are specialist sedation techniques
and they risk causing unintended deep sedation
or anaesthesia. The incidence of associated
airway obstruction and inadequate spontaneous
ventilation may be dependent, in the main, on
skill and judgement.
Basic and advanced conscious sedation
in dentistry
In dentistry in the UK, conscious sedation techniques are of two types: basic and advanced
(formerly known as standard and alternative).2
Advanced techniques have a reduced margin
of safety and should only be used by a
specialist team.
Background
Demand for sedation in children
Many children undergoing minor procedures
need effective sedation, or anaesthesia, because
they are frightened, in pain, ill, or have behavioural problems. Some procedures are very
common and anaesthetists should know what
sedation techniques are effective and likely to be
used by other healthcare practitioners. In children
presenting for anaesthesia, occasionally, it may
be appropriate to use conscious sedation instead.
Sedation is specific to the procedure
Four common scenarios, listed in Table 2,
require specific sedation techniques.3 Other
procedures require sedation, but the principles
of the four common scenarios can usually be
applied appropriately.
Conscious sedation in children
can be time-consuming
Children who refuse to undergo a procedure
‘awake’ are difficult to sedate to the moderate
or conscious level. Conscious sedation requires
patience, skill, time, and in many circumstances
the child has to cooperate during the procedure.
Provided the sedation failure rate is sufficiently
small, the time investment may be worthwhile
and anaesthesia resources can be saved.
doi:10.1093/bjaceaccp/mks008
Advance Access publication 29 February, 2012
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Conscious sedation in children
Table 1 ASA levels of sedation
Sedation level
Response to stimulation
Associated airway, breathing
and cardiovascular effects
Minimal sedation
Awake and calm
Responds normally to verbal command
Cognitive function and coordination may be impaired
None
Moderate sedation
Sleepy but easily roused
Responds purposefully to verbal command or light tactile stimulation
Reflex withdrawal from a painful stimulus is not a purposeful response
Not appreciable
Airway is maintained
Spontaneous breathing is adequate
Cardiovascular function is usually maintained
Deep sedation
Asleep and not easily roused
Responds purposefully to repeated or painful stimulation.
May be appreciable
May require assistance to maintain a patent airway
Spontaneous ventilation may be inadequate
Cardiovascular function is usually maintained
Table 2 Four different common sedation scenarios. *Ketamine sedation is unique
and described as dissociative. High-dose ketamine causes anaesthesia and airway
obstruction
Procedure
Example
Special issues
Painless imaging
Magnetic resonance
imaging
Painful procedures
Suture of laceration,
manipulation of a
fracture
Gastrointestinal
endoscopy
Gastroscopy and
colonoscopy
Dental procedures
Extractions
Immobility usually requires the
patient to be asleep and not
disturbed
Use local anaesthesia whenever
possible
Conscious sedation for cooperative
patients
Ketamine is an effective analgesic
and immobilizing sedative*
Conscious sedation for cooperative
patients
Colonoscopy is not usually painful
unless the colon is distended
Conscious sedation for cooperative
patients
Local anaesthesia is important
Delayed effects of opioids are
dangerous
Conservation
medicine doctors. The recent UK NICE guideline (number 112)3
recommends:
† that healthcare professionals using specialist sedation techniques need to be trained to administer sedation drugs safely, to
monitor the effects of the drug and to use equipment to maintain a patent airway and adequate respiration.
† A healthcare professional trained in delivering anaesthetic
agents is available to administer sevoflurane, propofol, or
opioids combined with ketamine.
Guidelines
Two UK guidelines are recent. The SIGN guideline concentrates
on safe moderate sedation techniques.4 NICE guideline 112 covers
all types of effective sedation, including specialist techniques and
recommends a framework of training to use them safely.3
General principles
Risk of unrecognized deep sedation
When a child will not cooperate, it is tempting to increase the
dose. In most techniques, for an individual child, it is not possible
to be certain what dose or doses can cause deep sedation. It is important therefore to always be prepared for deep sedation. Sedation
should only be undertaken where there are the facilities, equipment, and personnel to prevent or manage deep sedation. The pain
of some procedures may be brief and patients may be vulnerable
to delayed respiratory depressant effects of potent opioids.
Controversy
The type of drug that can be used safely by non-anaesthetists is
controversial. Where anaesthesia services are not available, ‘specialist’ drug techniques have been used by non-anaesthetists in
the UK. Ketamine, for example, is being used by emergency
The following principles of the ‘patient journey’ are fundamental
to the safe delivery of anaesthesia, and also sedation. They are
summarized to illustrate how conscious sedation can be delivered
effectively, safely, and appropriately.
Pre-sedation assessment
The psychological and developmental status will help to decide
whether a child is likely to cooperate with conscious sedation.
Conscious sedation is unlikely to be successful in infants and
small children. Likewise, anxious patients are probably unsuitable
unless they are motivated.
There are risk factors that may influence the choice of technique and the consenting process. In addition to understanding the
current medical and surgical problems, the sedationist should
assess the child’s growth, previous sedation or anaesthesia, and the
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Conscious sedation in children
drug history. The examination should identify any physical
abnormalities, particularly those of the airway.
example, i.v. access may not be necessary for nitrous oxide alone,
choral hydrate for painless imaging, or for i.m. ketamine.
Consent
The child and parents should be told what the procedure involves,
the proposed sedation, the alternatives to sedation, and the risks
and benefits. Written informed consent should be taken.
Fasting
Fasting is not needed for minimal sedation, sedation with nitrous
oxide alone, or conscious sedation using ‘wide margin of safety’
techniques. Fasting, as for anaesthesia, is recommended for any
conscious sedation technique in which verbal contact may be lost.
In an urgent situation with a child who is not fasted, the risks of
aspiration during the chosen sedation technique should be weighed
against the consequences of delay in the procedure.5
Psychological preparation
Much may be gained by spending time preparing a child psychologically. In any event, conscious sedation involves a degree of
assent and some explanation will be necessary. The explanation,
aided by written information, may cover the procedure, what the
child will experience, what they should do, and how they will
cope. The parents or carers can help reassure the child and may be
helpful during the procedure itself.
Common scenarios
Painless imaging
Conscious sedation, in which the child is rousable by verbal
command, is unlikely to be successful if the child will not assent
to lie still. If the child is anxious, and an anxiolytic is effective,
short scans are possible. Usually, however, children fall into two
groups: those who can be persuaded to lie still without any sedation and those who need sedation deeper than conscious sedation.
In the second group, the sedation technique will only be successful
if the child sleeps. It is a mute point as to whether a sleeping child
can be roused or not because it is counter-productive to attempt to
rouse a child before or during a scan. For this reason, the techniques described here for painless imaging are probably not conscious sedation. Nevertheless, they are included because they may
be moderate and their margin of safety is wide. The term ‘safe
sleep’ has been used for these techniques because the incidence of
airway obstruction is rare—although it is described in large case
series. In the author’s hospital, a list of contraindications to
sedation has been helpful in selecting children in whom anaesthesia is the safer option (Table 3).
Table 3 Common contraindications to sedation
Personnel and training
Airway problems
Healthcare professionals involved should understand and be competent in the technique being used. This should include the
pharmacology, applied physiology, patient assessment, monitoring,
and care in recovery. They must be able to recognize and manage
any complications (see UK Nice guideline 112 for further
details).3 Practitioners should have trained assistants.
Apnoeic spells
High intracranial pressure
Clinical environment and monitoring
Epilepsy
Monitoring is not considered necessary for nitrous oxide alone.
For other moderate or conscious sedation techniques, the minimum
standard or monitoring is with continuous oxygen saturation and
heart rate by pulse oximetry. For specialist conscious sedation
techniques, ECG, arterial pressure, and capnography may be
needed and should be available. Sedation management and monitoring should be documented. After the procedure, monitoring
should continue until there is no risk of further reduced level
of consciousness. Any nausea, vomiting, and pain should be
adequately managed before discharge.
I.V. access
I.V. access may be difficult in children and, whenever delivery of i.v.
drugs and fluids are unnecessary, or not likely, it may be omitted. For
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Respiratory disease
Risk of pulmonary aspiration
of gastric contents
Severe metabolic, liver, or
renal disease
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Actual or potential airway obstruction, e.g. snoring or
stridor, blocked nose, small mandible, large tongue
Related to:
Brain damage
Drug treatment
SpO2 ,94% in air
Respiratory failure (high respiratory rate, oxygen
treatment)
Inability to cough or cry
Drowsiness
Headache
Vomiting
Convulsions requiring rectal diazepam within the
last 24 h
Rectal diazepam used more frequently than once in
2 weeks
Seizure related to sedation
Resuscitation within the last month
Major neurological or neuromuscular disease
associated with, e.g. apnoeic spells or hypotonia
Intracranial hypertension
Convulsions with cyanosis more frequent than once
per day
Convulsion ,4 h before sedation
Failure to regain full consciousness and mobility
after a recent convulsion
Abdominal distension
Appreciable volumes draining from NG tube
vomiting
Requiring i.v. fluids or dextrose
Jaundice or abdominal distension
Requiring peritoneal or haemodialysis
Conscious sedation in children
Two common sedation techniques are recommended:3
† Chloral hydrate for children under 15 kg. This oral drug,
given in doses up to 100 mg kg21 (maximum dose 1 g),
usually causes sleep within 10 min that lasts for 1 h. Its
effect is variable, however, sometimes taking 60 min to sleep
onset. I.V. cannulation is not necessary for oral sedation; it
may be necessary for contrast media administration.
† Midazolam. There is little published evidence of the efficacy
of this drug in this scenario yet it remains in common use.
I.V. doses should be titrated to effect. Starting and increment
doses are 25 –50 mg kg21. The BNFc maximum recommended doses are 6, 10, and 7.5 mg for children aged 1
month–6 yr, 6–12, and 12 –18 yr, respectively.6
If these are not suitable or effective deep sedation or anaesthesia
with propofol or sevoflurane is necessary. Dexmedetomidine,
given i.v. in high doses, is also effective at achieving moderate
sedation for imaging;7 it is not available in the UK.
Painful procedures
In emergency departments and in hospital wards, some painful
procedures can be managed using conscious sedation. Wound care
and manipulation of fractures are common examples. Minimal sedation can be achieved with:
† Nitrous oxide. In a maximum concentration of 50% in
oxygen, it should be ‘self-administered’ by the patient.
† Midazolam (oral or intranasal). Oral midazolam (0.5 mg
kg21) is an effective anxiolytic within 30 min. Nasal midazolam (0.2 mg kg21) has an onset as fast as the i.v. route; nasal
drops are painful, atomized midazolam is much less so. The
buccal route is also useful.
Such techniques require patient cooperation. In all cases, a local
anaesthetic should be used if possible. Other non-sedative analgesics are important also for pain control after the procedure. When
these are not effective, more potent drugs are needed. Two techniques are recommended:3
† Ketamine. The sedative effect is unique and called ‘dissociative’; children are immobile, calm, unreactive to pain yet their
eyes may remain open. The state does not fit easily into the
ASA levels, nevertheless ketamine is not considered to be
conscious sedation. Airway and breathing reflexes are usually
maintained but expect a low incidence of laryngospasm
caused by airway secretions. Recovery is usual within 90 min.
Recommended doses are either 2 mg kg21 i.v. (give additional doses of 1 mg kg21 if necessary) or 5–10 mg kg21 i.m.8
† Midazolam (i.v.) with or without fentanyl (i.v.) can be used
to achieve moderate sedation. The doses of both drugs should
be titrated carefully and will depend on the degree of pain; a
starting dose of midazolam is 25 –50 mg kg21. The effect of
fentanyl may outlast the pain so that once the procedure is
over, the fentanyl may cause respiratory depression. A starting
dose of fentanyl is 0.25–0.5 mg kg21.
Of the two techniques above, ketamine is more reliable. Even
though it causes sedation deeper than the ‘moderate’ level, it has
less respiratory effects, requires less judgement, and less intervention than a combination of midazolam and fentanyl.9 When either
of these techniques is unsuitable, a specialist technique or anaesthesia should be used.
Dental procedures
The mouth shuts during sleep and therefore, provided a mouth
prop is not used, an open mouth is evidence of consciousness
during sedation. The pain of dental treatment is notoriously severe
and therefore the use of local anaesthesia is important. Once local
anaesthesia has been injected and is working, requirements for
sedation may be much less.
In the UK, dental conscious sedation is divided into basic and
advanced (formerly standard and alternative).3 Standard conscious
sedation requires the cooperation of the child and involves one of
the two techniques given below.
† Nitrous oxide is administered via a nasal mask in concentrations up to 70%.
† Midazolam, titrated i.v. is recommended for anxious adolescent children and young people. A starting dose is
25 –50 mg kg21.
Both of these techniques have an excellent success and safety record.
If these sedation techniques are not suitable or sufficient, either
an advanced sedation technique or anaesthesia should be considered. Specialist teams are available in some parts of the UK. The
specialist techniques themselves involve the use of combinations
of potent drugs and there may be a risk, depending on the drugs
and their doses, of unintended deep sedation.
Endoscopy
Some adults can swallow an endoscope or accept the indignity and
discomfort of colonoscopy without any sedation. Colonoscopy is
uncomfortable but not usually painful except when the colon is
stretched, often during biopsy of the terminal ileum. Children,
however, almost always require sedation and many prefer anaesthesia. Propofol sedation or anaesthesia, without tracheal intubation,
is being used widely but, almost certainly the level of sedation is
not conscious. Nevertheless, endoscopy is possible under conscious
sedation in many children using i.v. midazolam and an opioid is
sometimes necessary. Both drugs should be titrated carefully. In
summary, two techniques are recommended:3
† Midazolam i.v. for upper gastrointestinal endoscopy. A starting dose is 25 –50 mg kg21.
† Midazolam combined with fentanyl (or equivalent opioid,
both i.v.) for lower gastrointestinal endoscopy. A starting dose
of fentanyl is 0.25 –0.5 mg kg21.
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Common pitfalls
occur in a recovery area, and staff must be ready to detect and
respond.
The following may be helpful to prevent patient harm.
Failure to assess the patient
Oxygen treatment
Identification of factors that inhibit success or reduce safety should
help prevent unnecessary distress or harm. Published lists of
common contraindications should be used to help guide the decision about whether anaesthesia is best.
Desaturation may indicate sedation deeper than the conscious
level. Oxygen treatment may be necessary but is much less important than maintaining patent airway and effective breathing.
Capnography should detect problems sufficiently early to prevent
oxygen desaturation.
Failure to choose the sedation technique appropriate
for the procedure
Paradoxical excitement
Painful protracted procedures in anxious, young, and unprepared
children are unlikely to be successful using conscious sedation. A
technique that can be converted to deeper sedation is appropriate,
provided it can be managed safely.
Inadequate training and resources
The performance of healthcare practitioners is the vital factor that
minimizes patient complications and distress. Training courses,
either within local organizations or by specialist colleges and
associations, are being developed in the UK.
Unrecognized deep sedation
Deep sedation from 50% nitrous oxide alone in an otherwise
normal healthy patient is extremely rare. Anxiolysis with i.v. midazolam is similarly safe. For all other sedation drugs, the pharmacokinetic and pharmacodynamic characteristics vary and therefore
most techniques have an incidence of unintended deep sedation.
The risk is dose-dependent. Sedation drugs that have a ‘wide
margin of safety’ are generally not short acting and therefore deep
sedation, should it occur, may be prolonged. The following two
principles are important:
† careful titration,
† not exceeding agreed dose limits.
Maximum dose limits, in practice, will depend upon the procedure
and patient characteristics and should be agreed locally or by specialist groups. The BNFc provides advice.6 Flumazenil (10 mg
kg21) and naloxone (100 mg kg21) may be necessary for the reversal of deep sedation and respiratory depression effects of midazolam and opioids.
Deep sedation after the procedure
The pain of a procedure helps to prevent deep sedation and oppose
the respiratory depression effects of opioids. Once the pain subsides, either because local anaesthesia has become effective or that
the procedure is shorter than the effective length of action of the
opioid, respiratory depression is possible. This problem could
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Some children are distressed by sedation and increasing doses may
not help. Midazolam can cause excitement which may be reversed
by flumazenil. Ketamine can cause distressing hallucinations.
Sedation by these techniques may need to be abandoned.
Declaration of interest
None declared.
References
1. Royal College of Anaesthetists and Royal College of Radiologists.
Sedation and Anaesthesia in Radiology. Report of a joint working party,
London, 1992
2. The Royal College of Anaesthetists and the Faculty of Dental Surgery of
the Royal College of Surgeons. Standards for Conscious Sedation in
Dentistry: Alternative Techniques. A Report from the Standing Committee
on Sedation for Dentistry. Available from http://www.rcoa.ac.uk/docs/
SCSDAT.pdf, 2007
3. National Institute for Clinical Excellence. Sedation for diagnostic and
therapeutic procedures in children and young people. Available from
http://guidance.nice.org.uk/CG112, 2010
4. Scottish Intercollegiate GN. SIGN guideline 58: safe sedation of children
undergoing diagnostic and therapeutic procedures. Paediatr Anaesth 2008;
18: 11–2
5. Green SM, Roback MG, Miner JR, Burton JH, Krauss B. Fasting and
emergency department procedural sedation and analgesia: a consensusbased clinical practice advisory. Ann Emerg Med 2007; 49: 454–61
6. Royal Pharmaceutical Society of Great Britain. British National Formulary
for Children. London: British National Formulary Publications, Royal
Pharmaceutical Society of Great Britain, 2011
7. Mason KP. Sedation trends in the 21st century: the transition to dexmedetomidine for radiological imaging studies. Paediatr Anaesth 2010; 20:
265–72
8. The College of Emergency Medicine. Guideline for Ketamine Sedation in
Emergency Departments. London: The College of Emergency Medicine,
2011
9. Kennedy RM, Porter FL, Miller JP, Jaffe DM. Comparison of fentanyl/midazolam with ketamine/midazolam for pediatric orthopedic emergencies.
Pediatrics 1998; 102(4 Pt 1): 956– 63
Please see multiple choice questions 33 –36.
Continuing Education in Anaesthesia, Critical Care & Pain j Volume 12 Number 3 2012