Management of Acute Poisoning

1. Management of Acute Poisoning

2. Principles of Management Among important toxicological principles that are applied in evaluating the poisoned individual are • Exposure and aspects related to reducing absorption • Dose response considerations • Target tissue and systemic effects • Chemical interactions • Chemical antagonism as a management approach • Acute versus Chronic effects

3. General Management 1) Supportive Care (to sustain the vital signs) • A Airway Clearance • B Breathing maintenance • C Circulation enhancement • D Decontamination 2) Treat the patients depressed mental status 3) Rule out or treat hypoglycemia

4. 4) Obtain history of the exposure • What substance was exposed • How much was consumed or exposed • Route of ingestion or exposure • Time since exposure 5) Identify Signs and symptoms of poisoning Breathing rate, heart rate, dilation of pupil, Fits, injuries or diseases associated to the symptoms 6) Neurologic Examination Slurred speech, imbalancement, tremors unconsciousness, seizures, confusion, headache

5. Toxicology Lab Tests • Advantages • Can confirm the poisoning agent • Predict anticipated toxic effects or severity of exposure • Confirm the diagnosis • Help in guiding therapy • Limitations • All chemical agents cannot be possibly screened • These are usually time consuming and cannot be provided as soon as treatment starts • The results may not apply to the diagnosis of all patients alike

6. Skin Decontamination • Is performed when percutaneous absorption of a substance may result in systemic toxicity or when the toxic substance may produce local toxic effects e.g. burns caused by acid • Clothing should be removed and skin should be irrigated by sufficient quantities of Water • Neutralization should not be attempted. This will only cause more pain to the patient and worsen the poisoning

7. Gastric Decontamination • It involves removal or ingestant from the gastrointestinal system and maybe carried out by the following • Emesis • Should not be attempted in Children or Depressed patients • Should not be attempted with Acid or Hydrocarbon poisonings • Should not be attempted with substances with an extremely rapid onset of action • Usually done by Ipecac syrup in a hospital, emesis starts in 30 minutes and lasts 2 hours and produces 3 episodes of emesis

8. Gastric Lavage • It is employed in patients who have consumed life threatening amounts of a drug within 1-2 hours • Used in patients who are not alert or not recommended with emesis • Lavage is performed after an endotracheal tube secures the airways • After aspiration of the gastric contents 250-300mL of water or saline is instilled and then aspirated • The sequence is repeated until the liquid returning becomes clear

9. Activated Charcoal • Adsorbs almost all commonly ingested chemicals and medicines and usually administered to overdose patients within 30minutes to 2 hours • It greatly reduces oral absorption of nearly all pharmaceuticals but should not be given if a patient is already vomiting

10. Whole Bowel Irrigation • It has been shown to be effective where activated charcoal lacks efficacy • Usually a cathartic solution like Poly ethyl glycol (PEG) is given orally through a nasogastric tube (1-2L/hr) until rectal affluent is clear • Administration of a cathartic agent may help in removal of toxins from the gastrointestinal tract and reduce absorption • Sorbitol (70%) is the most preferred cathartic agent Cathartics

11. Urinary Decontamination • Forced Diuresis and urinary pH manipulation • Maybe used to enhance elimination of substances whose route of elimination is primarily renal and those that show little protein binding • Acid Diuresis by Sodium bicarbonate : • promotes ionization of weak acids thereby preventing their reabsorption in the kidneys e.g barbiturates • Alkaline Diuresis by Ascorbic Acid : • Promotes elimination of weak bases e.gquinolones

12. Blood Decontamination • Heamodialysis • For chemicals already absorbed into the blood and in severe cases of intoxication heamodialysis is recommended • Substances removed by heamodialysis generally are water soluble and have a small volume of distribution so are not protein bound

13. Heamoperfusion • It is a technique where anticoagulated blood is passed through a column containing activated charcoal or resin particles. • this is more rapid than heamodialysis but it does not correct fluid or electrolyte abnormalities as in case of hemodialysis

14. Reducing Toxicity by Antidotes • An antidote can simply be defined as a clinical treatment using a chemical to counteract the effects of another • The ultimate goal is to reduce toxicity by interacting with the toxicant in ways that • Directly inhibit its effect through modification of its chemical properties • Inhibit its effect by altering its physical properties • Reduce effects at its sites of action • Facilitate its elimination

15. Common Antidotes

16. Summary • Rapid assessment of patient with management • Consider need for clinical chemistry • Whether it is possible to limit further absorption or attempt its elimination • Considering antidotes • Considering further advice and information