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GI Decontamination. YC Chan. Poisoning Management. 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.
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GI Decontamination YC Chan
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 • 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. . .
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 + AC Lavage + 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 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 • Problem • Excluded patients that ingested non charcoal binding drugs • 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
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
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