Post on 31-Dec-2015
description
Drug OverdoseDRUG OVERDOSEManagement Principles and
Decontamination
HistorySpeak 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
InvestigationABG
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
TreatmentComa 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 EvidencePosition 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 IISchedule 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