Gastric lavage only be done in those patients who arrive within 1 to hours after taking highly toxic pesticide. However there are special concerns too in giving those patients who are agitated non-compliant or non-intubated drowsy , unconscious patients , in these there is major risk of complications including death. Once a decision to carry out a lavage is made, at least 300ml of water or normal saline should b given after aspirating the stomach contents through a nasogastric tube. Care should be taken to avoid larger volumes of fluid as it may push the poison into the small bowel. Ethencity should be checked by measuring the amount of fluid taken off to ensure that fluid is not left in the stomach.
At the end of the lavage a dose of activated charcoal can b left which would b not harmful.
Loading with atropine and IV fluids
?????????????????????????????????? Give atropine 1.8'3 mg (three to five 0.6 mg vials) rapidly IV into a fast-flowing IV drip.
when clinical presentation is not clear, administer atropine 0.6'1 mg. A marked increase in heart rate (more than 20'25 beats/min) and flushing of the skin will suggest that there is no significant cholinergic poisoning and there us no need to give further atropine .
Give 500'1000 ml (10'20 ml/kg) of normal saline over 10'20 min.
After three to five minutes of giving atropine air entry should be checked on chest auscultation, heart rate, and blood pressure.
When all the parameters remain within normal range, the patient has received enough atropine and is 'atropinised' but ifeven after 3'5 min of atropine dose a consistent improvement does not seen across the three parameters, then dose of atropine should be doubled, and continued to doubled every time till there is no response
Atropinise the patient as quickly as possible.
Atropine treatment after atropinization
Atropine infusion should be considered by giving 10'20% of the total amount of atropine that was required to load the patient every hour, after patient became atropinised (adequate aeration of lungs, heart rate [more than 80 beats/min] and blood pressure [more than 80 mmHg systolic with good urine output], dry skin, and pupils no longer pinpoint).
Observation of the patient
Three parameters should be monitored every 15 min to see whether the atropine infusion dose is adequate or not.
Once effect of atropine is lost with symptoms ofrecurrence of bronchospasm or bradycardia, dose of atropine bolus should be given and atropine infusion rate should be increased till they disappear.
Once the parameters become settled, Observe the patient at least hourly for the first 6 hours to check that the atropine infusion rate is sufficient and that there are no signs of atropine toxicity.
As the parameters settled and required dose of atropine decrease, observation for recurrence of cholinergic features can be done less frequently (every 2'3 hours).
Excess dose of atropine causes side effects like agitation, confusion, urinary retention, hyperthermia, bowel ileus and tachycardia
So atropine infusion should be stoped.
Monitoring should be done again after 30 min to see whether the features of toxicity have settled.
If still not settled , continue to monitor every 30 min or so.
When they settled, atropine should be restarted at 70'80% of the previous dose
.Place a towel soaked with water over the patient's chest and place in a fan's airflow. Cold water and soaked towels can also be placed at points of maximum heat loss (for example axillae, groins)because hyperthermia is one of the serious complication of atropine in hot and humid wards
Start Diazepam 10 mg given by slow IV push as it decreases the agitation, repeated as necessary in an adult, up to 30'40 mg per 24 hours.
Tying a non-sedated agitated patient to the bed is associated with complications, including death. Excessive body heat is generated when these patients forces or struggles against their bonds, this also result in hyperthermic cardiac arrest.
Oximes and other therapies
The Elephant Formulary '' 2003-06 Susan K. Mikota DVM and Donald C. Plumb, Pharm.D. Published by Elephant Care International - www.elephantcare.org Elephant specific information, if available, is in blue.
Chemistry - A quaternary ammonium oxime cholinesterase reactivator, pralidoxime chloride occurs as a white to pale yellow, crystalline powder with a pKa of 7.8-8. It is freely soluble in water. It is commercially available in injection and has a pH of 3.5-4.5 after its reconstitution. The other name of Pralidoxime is 2-PAM Chloride , or 2-Pyridine Aldoxime Methochloride .
Storage/Stability/Compatibility ' It should be stored at room temperature until unless otherwise instructed by the manufacturer.. After reconstituting with sterile water for injection, the solution should be used within a few hours. Sterile water which contains preservatives should not be used for reconstituting..
Pharmacology - Certain organophosphates inactivate the cholinesterase by phosphorylation. Pralidoxime reactivates cholinesterase Via nucleophilic attack, the drug removes and binds the offending phosphoryl group attached to the enzyme and is then excreted.
Uses/Indications - Pralidoxime is used , often in combination with atropine and as supportive therapy in the treatment of organophosphate poisoning..
Pharmacokinetics - Pralidoxime are now no longer available in oral form in the United States as it is only marginally absorbed through oral route. It is distributed primarily throughout the extracellular water. Its penetration to CNS is not in significant quantities because of its quaternary ammonium structure, but recent studies and clinical responses have led some to question
this. Pralidoxime is thought to be metabolized in the liver and excreted as both metabolite(s) and unchanged drug in the urine.
Contraindications/Precautions/Reproductive Safety - Pralidoxime is contraindicated in patients hypersensitive to it. In carbamate poisoing it is not recommended because it is rapidly reversible after its inhibition, but controversy exists regarding this issue.
In patients those receiving anticholinesterase agents it should be used causiously as it may precipitate a symptoms like myasthenic crisis in mysthania gravis patients. In renal impairment dose should be used and used cautiously..
Adverse Effects/Warnings - Pralidoxime generally is safe and free of significant adverse effect in usual dosag however rapid IV injection can cause tachycardia, muscle rigidity, transient neuromuscular blockade, and laryngospasm.
For effectiveness Pralidoxime must be given within 24 hours of exposure , but some benefits may occur, particularly in large exposures, if given within 36-48 hours.
Overdosage/Acute Toxicity - The acute LD50 of pralidoxime in dogs is 190 mg/kg and, at high dosages, exhibits symptoms of its own anticholinesterase activity. Symptoms which shows toxicity included are muscle weakness, ataxia, vomiting, hyperventilation, seizures, respiratory arrest and death.
Drug Interactions - Anticholinesterases can potentiate the action of barbiturates; use with caution. Cimetidine can potentiate organophosphates actions by slowing down its metabolism.
Use of succinylcholine, theoph...
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