Drug Overdose
Download
Report
Transcript Drug Overdose
Drug
Overdose
DRUG OVERDOSE
Management Principles and
Decontamination
History
Speak to:
patient
relatives
ambulance officers
Ask
what drug was ingested
when
how much
Examination
LOC GCS
uniformly used
developed for prognosticating head injuries
verbal and pain response most useful in
DSPs
• AVPU
Vital signs
Temp/PR/BP/RR/SpO2
Examination
Mini-Neuro
Pupil size and reaction
Reflexes
Gross assessment of muscle tone
Chest/CVS as appropriate but low yield
BS may be in anticholinergic toxidrome
Investigation
BSL
mandatory if LOC
ECG
always done
findings very specific
QRS complex
indicative of Na+ channel blockade if
prolonged
Investigation
Normal QRS is < 100 ms
QT interval
<420 ms male <440 children <450 female
may be prolonged in certain poisonings
neuroleptics esp. thioridazine
QT or QTc ?
Standardises QT to a rate of 60 bpm
only useful if heart rate <70 or >50
Investigation
Concentrations are useful if suggestion of
poisoning with
salicylates
paracetamol
lithium
valproate
theophylline
No use as a screening tool
Investigation
ABG
Useful in assessing ventilatory status
Useful if ingestion can cause metabolic upset:
(VBG)
salicylate
metformin
OR
if patient needs serum or urinary
alkalinisation
Investigation
Miscellaneous:
CXR if aspiration suspected
CT brain if story not c/w clinical findings
CK if unconscious for some time
K+ in digoxin poisoning
Close
attention to ABC and
supportive care is all that is
required to manage MOST drug
overdoses
GCS/vital signs/mini neuro and
ECG are only tests/investigations
likely to alter management with
a few notable exceptions
Treatment
May be specific antidote
NAC in paracetamol poisoning
May be general/empiric
decontamination
coma cocktail
generous IV fluid replacement
Treatment
Coma cocktail
Dextrose/Thiamine/Naloxone/Flumazenil
Problems
hypoglycaemia can be assessed with BM
stix
Naloxone can precipitate acute
withdrawal
Flumazenil may complicate further
seizure management
Decontamination
When should patient be decontaminated?
risk of morbidity and/or mortality associated
with ingestion
What type of decontamination should be
used?
Depends on clinical circumstances and other
treatment options
Decontamination
Syrup of Ipecac
Gastric lavage
Activated charcoal
• multi dose
• with cathartic
Whole bowel irrigation
Where is the Evidence ?
Based on
Animal studies
Volunteer studies
clinical studies
Difficulty due to
serious ingestions excluded
conflicting results
Where is the Evidence
Position statements released in 1997 by
AACT and EAPCCT
“Overall the mortality from acute poisoning is
less than 1 % and the challenge for
clinicians is to identify promptly those who
are at most risk of developing serious
complications and who might potentially
benefit, therefore, from gastrointestinal
decontamination.”
Syrup of Ipecac
Plant extract previously abused by bullimics
needs to be given EARLY
induces vomiting by gastric and central
mechanism
Contraindicated in
unprotected airway
corrosive
very little evidence for or against
possible role in the home for children
Gastric lavage
No studies demonstate efficacy even < 60
min.s
Studies exclude serious poisonings
Contraindicated:
dodgy airway reflexes
corrosives
hydrocarbon
Gastric lavage
May increase risk of aspiration
May lead to pharyngeal injury
alleged to increase absorption in some cases
Has lead to significant return of ingestants
up to 12 hours post ingestion(salicylates)
Indication
Serious life threatening poisoning with
well protected airway
(level IV evidence)
Activated charcoal
Will adsorb many toxins in GI tract BUT:
• Alcohols
• Li+, Fe 2+ (probably all alkali metals)
Ratio should be 10:1 AC:toxin
Evidence from volunteer studies that
absorption will be if < 60 min.s
Little to suggest benefits outcome clinically
or absorption post 60 min.s
DO NOT GIVE ROUTINELY
Activated charcoal
Beware the unprotected airway or aspiration
risk
dose is 50g adult, 1g/kg in a child
Cathartics
Alleged to increase bowel transit time of
toxin
Evidence only from animal and volunteer
studies
Unlikely to benefit
Multi dose activated charcoal
Works by
• GI dialysis
• drugs with significant enterohepatic circulation
examples:
•
•
•
•
theophylline
anticonvulsants
salicylates
digoxin
Multi dose activated charcoal
Good, though indirect evidence of effect in
digoxin poisoning
50g q 6 hrly OR by NG infusion if intubated
up to 1g/kg suggested for serious
theophylline poisonings
Justifies “late” instigation of charcoal
Whole bowel irrigation
Used for
SR/EC preparations
when charcoal is ineffective
No controlled clinical studies to back up use
physically speeds up transit through GI tract
single dose charcoal given prior to starting
Whole bowel irrigation
PEG ELS (“go-lytely”) is used does not
cause significant water/electrolyte
disturbance
frequently causes vomiting, requires NGT
airway must be protected
ileus is CI but has been reversed with
neostigmine
dose is 15-20 mls/kg/hr
endpoint is clear rectal effluent, median
time to achieve this is 6 hours
Duty of Care
Ingestion of an overdose renders a patient
incompetent
If requires hospitalisation for physical
effects of drug overdose
• keep under duty of care
If no medical issues and attempts to leave
Schedule II
Take home messages
History, focused exam and a few tests,
supportive care +/- period of observation is
appropriate management for most DSPs
Ipecac is never used, gastric lavage
occasionally
Charcoal is only given if likely to benefit
Patients receiving decontamination must
have airway protection