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GI Decontamination

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					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
   Get it out
   Hold it there
   Push it down
                    Principle
Primum Non Nocere
   First, do no harm
No one strategy can treat all situations
   Good and bad
Benefit Vs Risk consideration
           2 Main Questions
Need of GI decontamination
   Yes or No
Choice of decontamination method(s)
   Induced vomiting
   GL
   AC/MDAC
   Cathartics
   WBI
   Surgical
              More questions
Try to answer
   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
   What is it?
   Dose
   Time of ingestion
   Co-ingestion
   Charcoal binding property
              Considerations
Patient factors
   Age/Size
   Spontaneous vomiting
   Clinical status now
   Co-morbid conditions


Physician and institution factors
   Experience and resources
   Attend this program or not !
               Oversea Data
TESS 2002
   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


   8% exposure had GI decontamination
   ~34% patient went to hospital had GI contamination
               Local Data (1)
UCH AED patients
   2000-2004
   ~ 1800 cases
      28% AC
      2.6% GL
      0.1% Induced vomiting
      0.2 % WBI


   ~30% had GI decontamination
               Local Data (2)
Multi-AED patients
   6 AEDs
   1/1/01-30/6/01
   ~ 1500 cases
      35% AC
      7% GL
      0% WBI
      0.1% Induced vomiting


   ~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
   When it work?
      Usually within 30 minutes, lasting 20 minutes to 2 hours
      Average episodes of emesis is 3
   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
   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:
   ~ 30% recovery
   Wide variation
              Gastric Lavage


                      . . .orogastric lavage




This refers to. . .
How to do it?
              Gastric Lavage
Complications
   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                                Obtunded, uncooperative




   1                   2                        3                         4

ipecac                                      Lavage
                    AC                                                   AC
 + AC                                       + AC
214 pts            262 pts                   72 pts                    44 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
   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
   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
         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
   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
       Including those present within 1 hour of overdose
        & manifest severe toxicity



Problem
   Excluded patients that ingested non charcoal binding drugs
                Overall Data
Not necessary in mild/moderate poisoning
In severe poisoning
   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
   Not clearly defined unfortunately
Benefit Vs Risk consideration in each case
Lower threshold in
   Intubated cases
   Ineffective alternative treatment
   Really sick and “dying”
               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”
   Increase the amount of pores and surface area
Mechanisms
   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
   Enterohepatic removal
   Enteroenteric removal
Slightly more effective than emesis or lavage
in human volunteers and poisoned animals
   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
   “1 g/kg”
   Optimal ratio: “10:1 ratio”
   50 g in adult
Multiple doses
   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:
   Prevent ongoing absorption
   Continue to enhance elimination
Indications
   Large overdoses
   Delayed dissolution (bezoars, masses)
   Prolonged release (SR preparations)
   Good evidence in carbamazepine, dapsone,
    phenobarbital, quinine, theophylline, “digitalis”
           Activated Charcoal
Contraindications
   Absent gut motility or perforation
   Caustic ingestion
   Loss of protective airway reflexes
Complications
   Aspiration pneumonitis
   Constipation
   Diarrhea
   Intestinal obstruction
               Cathartics
Increase gastrointestinal movement
Generally not found beneficial
Multiple-dose cathartics can cause life-
threatening 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
   Iron, lithium and other metals
Body packers and stuffers
Sustained release products
                          WBI
Dose
   300-500 cc/hr in children
   1-2 L/hr in adults, until effluent in clear
   PRN R/T
Contraindications
   Bowel obstruction or ileus
   Haemodynamically instability
       Whole Bowel Irrigation
Complications
   WBI can displace drug from charcoal
   Labor intensive, and very messy
   Bloating
   Vomiting
       Liberal use of antiemetics
   May affect ventilation in vulnerable patient
Surgical removal
                   Summary
GI decontamination should be considered in
   Life-threatening presentations
   Large amount of toxic ingestions
   Unstudied scenarios
GI decontamination is probably unnecessary in
   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

				
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