Ways of Gastrointestinal Decontamination After Poisoning!

 GASTROINTESTINAL DECONTAMINATION AFTER POISONING

GI-decontamination can be achieved by the administration of:

1. Activated Charcoal
2. Gastric Lavage
3. Ipecac-induced Emesis
4. Whole-Bowel Irrigation

Indication for GI-decontamination:

• Ingestion of a known toxic dose
• Ingestion of an unknown dose of a known toxic substance
• Ingestion of a substance of known toxicity

*For all methods of GI-decontamination, the value of the procedure diminishes with time. Some investigators now question the usefulness of gastric lavage, or ipecac-induced emesis more than 1 hr after ingestion.*

*In general, activated charcoal is the most useful agent for preventing absorption of ingested toxic substance. Other methods may be considered if the ingested substance is not adsorbed by activated charcoal or if circumstances do not permit its prompt administration. *

1.Activated Charcoal:

• Activated charcoal is a non-specific absorbent that binds unabsorbed toxins within the GIT. 
• Activated charcoal is not effective for absorbing strong acids and alkalis, cyanide, methanol, ethylene glycol, iron or lithium.

Administration:

1. Activated charcoal is administered orally or by gastric tube in doses that range from 30-120g.
2. Activated charcoal is commercially supplied as slurry in water or a concentrated solution of sorbitol. The water-based products are preferred because the large amount of sorbitol that accompanies a typical dose of activated charcoal can result in excessive sorbitol-induced catharsis, producing fluid and electrolyte imbalance. Gentle encouragement may be needed to make the children swallow the charcoal. Having the child to take the liquid through a drinking straw from an opaque container is sometimes helpful.
3. Activated charcoal administration is commonly followed by the administration of cathartic (e.g., sorbitol, magnesium citrate, or magnesium sulfate) to hasten the elimination of the activated charcoal-toxin complex. There is no evidence to support the cathartic use.
4. Alert the patient that charcoal will cause the stools to turn black.
5. Repeat the oral doses of activated charcoal (such as 25g every 2hr.) have been used to enhance the elimination of some drugs, most notably Carbamazepine, Dapsone, Phenobarbital, Quinine, or Theophylline. Multiple doses activated charcoal s suitable only for patients with Active bowel sounds. Co-administration of a cathartic is not recommended during multiple doses activated charcoal therapy.

2.Gastric Lavage:

• Gastric lavage can be used to remove toxic substances poorly adsorbed by activated charcoal. Lavage is contraindicated for patient's wo have ingested corrosives or aliphatic hydrocarbons (gasoline) and for patients at risk for Esophageal or gastric perforation due to underlying medical conditions (e.g., esophageal varices).

Administration:

1. If the patients gag reflex is weak or absent, the airway must be protected by the use of Cuffed-endotracheal tube.
2. The largest possible orogastric tube should be used (26-28 F for children and 34-42 F for adults): the larger the tube diameter, the more efficient the lavage. The tube should be introduced through the mouth with the aid of a water-soluble lubricant. Nasogastric passage is not recommended.
3. Gastric lavage may be done with water., but a solution such as 0.45% NaCl may be used to minimize the risk of dilutional hyponatremia, especially in children. Aliquots up to 100mL in children and 200mL in adults in adults in adults are introduced through the tube and the removed (by gravity or suction-assisted drainage). The lavage should be continued for several cycles after the returning fluid is clear. Warming the lavage fluid reduces the risk of hypothermia.

3.Induction of Emesis:

• Do not induce emesis if the patient is experiencing or is at the risk of CNS depression, seizures, or at the loss of gag reflux, or if the patient has ingested a caustic substance or a hydrocarbon with high aspiration potential such as gasoline.

Administration:

1. Induce emesis only with syrup of ipecac. Salt, water, mustard water, or other home remedies or gagging have no place in the management of the poisoned patient. These techniques are ineffective and can be dangerous.
2. The usual initial dose of syrup of ipecac is 30mL in persons older than 12 years; 15mL in children 1-12 years old; and 10mL in children between the age of 6 months to 1 year.
3. Give the patient the additional water to drink: 125-250mL in children; 250-500mL in adults. Activated charcoal should not be given until after ipecac-induced emesis has occurred.
4. Emesis usually occurs within 15-20 minutes. If 30 minutes have passed without emesis, administer an additional dose of syrup of ipecac and more water.
5. Have the patient vomit into the bowl or other container so that the vomitus can be inspected for the presence of the ingested toxin.

4.WholeBowel Irrigation:

• Whole-bowel irrigation with an orally administered polyethylene glycol electrolyte solution is commonly used before bowel procedures.
• It has drawn attention as an alternative to other methods of GI decontamination in the management of acute poisoning. 
• Results of studies are promising, and the technique may have value in cases of ingestion of iron, enteric-coated or sustained-release products, foreign products, and drug-smuggling packets.
• Instillation rates have ranged from 500mL/hr. in children to 2L/hr. in adults.
• Typically, 4-6 L of fluid is administered.
• The endpoint is clearing of the rectal effluent.

Contraindication: to the whole-bowel irrigation are present vomiting, adynamic ileus, bowel obstruction or perforation, and GI hemorrhage.