Transcript GI Decontamination

GI Decontamination
YC Chan
Poisoning Management
Specific Treatment
Antidote
Decontamination
Supportive Management
Exposure Prevention
Basic Concept
Inside of the gut is outside of our body
3 Ways
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Get it out
Hold it there
Push it down
Principle
Primum Non Nocere
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First, do no harm
No one strategy can treat all situations
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Good and bad
Benefit Vs Risk consideration
2 Main Questions
Need of GI decontamination
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Yes or No
Choice of decontamination method(s)
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Induced vomiting
GL
AC/MDAC
Cathartics
WBI
Surgical
More questions
Try to answer
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Is the ingestion potential lethal?
Is there any thing left in the GI tract now?
Is getting out the thing from GI tract do good to the
patient clinically?
Risks or potential complications of your choice of GI
decontaminations
Alternative management available?
Considerations
“Poison” factors
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What is it?
Dose
Time of ingestion
Co-ingestion
Charcoal binding property
Considerations
Patient factors
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Age/Size
Spontaneous vomiting
Clinical status now
Co-morbid conditions
Physician and institution factors
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Experience and resources
Attend this program or not !
Oversea Data
TESS 2002
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2,380,028 exposure
22% hospital management
GI decontamination
6% (28%) AC
1% (4.5%) GL
0.5% (? 2.3%) Induced vomiting
0.1% (0.05%) WBI
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8% exposure had GI decontamination
~34% patient went to hospital had GI contamination
Local Data (1)
UCH AED patients
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2000-2004
~ 1800 cases
28% AC
2.6% GL
0.1% Induced vomiting
0.2 % WBI
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~30% had GI decontamination
Local Data (2)
Multi-AED patients
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6 AEDs
1/1/01-30/6/01
~ 1500 cases
35% AC
7% GL
0% WBI
0.1% Induced vomiting
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~40% had GI decontamination
From the data
~ 1/3 of “poison” exposed AED patients had GI
decontamination
Most just had AC
GL less likely
WBI/Induced vomiting rare
It is just a fact !
Don’t know whether it is good or bad for patient
outcome!
Methods of GI decontamination
Induced Vomiting
GL
AC/MDAC
Cathartics
WBI
Surgical
Induced Vomiting
Induced Vomiting
Syrup of Ipecac
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When it work?
Usually within 30 minutes, lasting 20 minutes to 2 hours
Average episodes of emesis is 3
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How much can we get it out?
Vary from 6-89%
Average ~ 25-30%
No better or worse than spontaneous vomiting or GL
Syrup of Ipecac
Dose
Contraindications
Complications
OUT !
Really no place for Ipecac?
Situation I will consider ipecac
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Pediatric
Lethal or serious morbidity
No expected vomiting or CNS toxicity shortly
Not amenable to GL or AC
Better than WBI
Gastric Lavage
Only removes toxins that fit through holes
In human volunteers and poisoned animals:
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~ 30% recovery
Wide variation
Gastric Lavage
. . .orogastric lavage
This refers to. . .
How to do it?
Gastric Lavage
Complications
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Mild respiratory depression
Increased vagal tone
Aspiration
Esophageal trauma
Airway trauma
Gastric trauma
Is Gastric Emptying necessary?
Before 1985
Many patients with overdoses were either administered
ipecac or gastric lavage
Kulig (1985)
630
592 drug OD patients, odd vs even days
Alert
1
ipecac
+ AC
214 pts
Obtunded, uncooperative
2
3
4
AC
Lavage
+ AC
AC
72 pts
44 pts
262 pts
Kulig K, Bar-Or D, Cantril SV, et al: Management of acutely poisoned patients
without gastric emptying. Ann Emerg Med 14:562-567, 1985
Results
Overall
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No difference in admissions and clinical course
Subgroup analysis
Conclusions
Satisfactory clinical outcome can be achieved
in OD patients w/o routine gastric emptying
Gastric lavage
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Questionable value if ingestion > 1hour
AC + supportive are sufficient in most cases
Problems
7 critical patient deliberately removed and was
given GL +AC
38 excluded due to deviation of the protocol
Artificial scoring system
Small no of sick patients
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Moderate 87
Severe 44
Only 1 death in the series
Merigian et al (1990)
10/86-3/88
808 patients
Even days
Odd days
Asymptomatic
AC (220)
Nothing (231)
Symptomatic
GE + AC (163)
AC (194)
Merigian KS et al. Prospective Evaluation of Gastric Emptying in the Self-Poisoned
Patient. Am J Emerg Med 1990;8:479-483
Results
No clinical differences in the observation groups
Significantly higher aspiration (8 vs 0) in GE +
AC Vs AC alone groups
Conclusions
GE is unnecessary for asymptomatic OD pts and
has limited clinical benefit in the routine
management of symptomatic patients
Problem – exclusion criteria
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APAP >140 mg/kg, lithium, MAOI’s, metals,
mushrooms, digoxin, toxic alcohols, and SR preps
Pond (1995)
Replicated the Kulig study w/ 876 patients
No differences between groups in all outcome
Clinical deterioration
Length of hospital stay
Complications
Mortality
80% power to detect 21-33% difference
80% power to detect 2x difference in the
severe pts
Pond SM, Lewis-Driver DJ, Williams GM, et al: Gastric emptying in acute
overdose: A prospective randomized controlled trial.
Med J Aust 163:345-349, 1995
Pond Study - Conclusions
GE + AC provided no benefit over AC alone
Gastric emptying can be omitted in treatment
of adult OD pts
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Including those present within 1 hour of overdose
& manifest severe toxicity
Problem
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Excluded patients that ingested non charcoal binding drugs
Overall Data
Not necessary in mild/moderate poisoning
In severe poisoning
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Inadequate no. of the sickest patients studied, who
would most likely benefit from gastric emptying
Just because a benefit wasn’t shown after one hour,
doesn’t mean that doesn’t exist !
My bottom line
GL did help certain poisoned patients
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Not clearly defined unfortunately
Benefit Vs Risk consideration in each case
Lower threshold in
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Intubated cases
Ineffective alternative treatment
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Really sick and “dying”
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Charcoal
History: used for 200 years
In 1930, French pharmacist Touery took 15
gm of charcoal mixed with a lethal dose of
strychnine in front of his colleagues, without
any toxicity
Activated Charcoal
“Activation”
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Increase the amount of pores and surface area
Mechanisms
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Non-covalent bonding, adsorption via ion-ion, dipole,
van der Waal’s forces
Does not effectively bind to hydrocarbons or metals
(i.e. iron, lithium), charged small molecules
Activated Charcoal
Adsorbs many toxins in vitro
Prevents absorption in vivo
Enhances elimination
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Enterohepatic removal
Enteroenteric removal
Slightly more effective than emesis or lavage
in human volunteers and poisoned animals
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Easier to use
Enterohepatic & Enteroenteric
Removal
Oral activated charcoal decreased serum t1/2 of iv
theophylline significantly
Berlinger WG et al. Enhancement of theophylline clearance by oral activated charcoal.
Clin Pharma Ther 1983. 33(3):351-4
Activated Charcoal
Single dose
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“1 g/kg”
Optimal ratio: “10:1 ratio”
50 g in adult
Multiple doses
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1-2 g/kg as a loading dose
0.5 – 1 g/kg every 2 - 4 hours for
3 – 4 doses
Only first dose with sorbitol !
Multiple Dose Activated Charcoal
Theory:
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Prevent ongoing absorption
Continue to enhance elimination
Indications
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Large overdoses
Delayed dissolution (bezoars, masses)
Prolonged release (SR preparations)
Good evidence in carbamazepine, dapsone,
phenobarbital, quinine, theophylline, “digitalis”
Activated Charcoal
Contraindications
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Absent gut motility or perforation
Caustic ingestion
Loss of protective airway reflexes
Complications
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Aspiration pneumonitis
Constipation
Diarrhea
Intestinal obstruction
Cathartics
Increase gastrointestinal movement
Generally not found beneficial
Multiple-dose cathartics can cause lifethreatening fluid and electrolyte problems
Okay with first dose of AC in adult
Whole Bowel Irrigation
WBI with PEG clearly decreases GI transit time.
Not associated with any clinically significant fluid or
electrolyte alterations
Human volunteers and poisoned animals absorb less toxin
Possible WBI Uses
Toxin not absorbed by charcoal
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Iron, lithium and other metals
Body packers and stuffers
Sustained release products
WBI
Dose
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300-500 cc/hr in children
1-2 L/hr in adults, until effluent in clear
PRN R/T
Contraindications
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Bowel obstruction or ileus
Haemodynamically instability
Whole Bowel Irrigation
Complications
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WBI can displace drug from charcoal
Labor intensive, and very messy
Bloating
Vomiting
Liberal use of antiemetics
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May affect ventilation in vulnerable patient
Surgical removal
Summary
GI decontamination should be considered in
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Life-threatening presentations
Large amount of toxic ingestions
Unstudied scenarios
GI decontamination is probably unnecessary in
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Delayed presentations and minimal symptoms
Small quantities of toxic substances
Large quantities of non-toxic substances
Prior significant emesis
Summary
AC is simple & safe, sufficient in most cases
GL only in serious poisoing and “reasonably” early
MDAC, WBI & rarely necessary
Cathritic – only in 1st dose with AC
Induced vomiting – fade out
Always consider the risk/benefit
ratio before performing a
decontamination procedure
Primum Non Nocere
Thank you !
Dinner time now