Introduction PT. 2 Flashcards
An abnormal, undesirable harmful, or effect to the well-being that is indicated by some measurable endpoint.
ADVERSE EFFECT
Chromosomal breakage resulting in rearrangement of pieces of chromosomes.
Loss, addition or rearrangement of chromosomes.
CLASTOGENESIS
Chemical with molecular weights of less than 1000 and generally react with endogenous carrier molecules to become antigens before they exhibit immunogenicity.
HAPTENS
A well-known example of a hapten is urushiol, which is the toxin found in poison ivy.
Heritable changes in genetic material that are limited to the effects on the nucleic acid.
Vinca alkaloids; Bromine containing cmpds.
MUTAGENESIS
Toxicity associated with any chemical substance.
INTOXICATION
on purpose
A clinical toxicity secondary to accidental exposure.
POISONING
Not on purpose
An intentional exposure with intent of causing self-injury or death.
OVERDOSE
Are drugs that have almost exclusively harmful effects
POISON
This means that a chemical will produce injury to one kind of living matter without harming another form of life, even though the two may exist close together.
SELECTIVE TOXICITY
Study of malformations induced during development conception to birth
TERATOLOGY
Synonymous with harmful in regard to the effects of chemicals
Or it relates to poisonous or harmful effects on the body
TOXIC
Refers to toxic substances produce naturally
TOXIN
Log dose that can produce 50% mortality in a population
Dose that is required to kill half the members of a tested population after a specified test duration
LD50 OR MEDIAN LETHAL DOSE
The ability of a chemical agent to cause injury in a given situation or setting
HAZARD
It is defined as the expected frequency of the occurrence of an undesirable effect arising from exposure to a chemical or physical agent.
RISK
Amount of exposure to a given agent that is deemed safe for a period of time.
THRESHOLD LIMIT VALUE (TLV)
Suggests that there should be a dose or exposure level below which harmful or adverse effects are not seen in a population
THRESHOLD DOSE
Quantity of agent that can kill an organism
LETHAL/FATAL DOSE
Denotes the altered pharmacodynamics of a drug when given in toxic dosage, since normal receptors and effector’s mechanisms may be altered.
TOXICODYNAMICS
Applied to the pharmacokinetics of toxic doses of chemicals, since the toxic effects of an agent may alter normal mechanisms for absorption, metabolism or excretion of a foreign material
TOXICOKINETICS
Is defined as the apparent
volume into which a substance is distributed.
VOLUME OF DISTRIBUTION (VD)
REMEMBER
A drug with a high Vd has a propensity to leave the plasma and enter the extravascular compartments of the body, meaning that a higher dose of a drug is required to achieve a given plasma concentration. (High Vd-> More distribution to other tissue).
Conversely, a drug with a low Vd has a propensity to remain in the plasma meaning a lower dose of a drug is required to achieve a given plasma concentration. (Low Vd-> Less distribution to other tissue).
LARGE VD >5L/kg
- Antidepressants
- Antimalarials
- Narcotics
- Propranolol
- Antipsychotics
- Verapamil
LARGE VD >5L/kg
SMALL VD <5L/kg
- Salicylates
- Phenobarbital
- Lithium
- Valproic Acid
- Warfarin
- Phenytoin
SMALL VD <5L/kg
A measure of the volume of plasma that is cleared of drug per unit time.
CLEARANCE
- Zero order (have a rate constant and half-life that is independent of the reactants’ concentrations)
- First order (have rate constants that are affected by the concentration of the reactants)
Total clearance is the sum of clearances by excretion by the kidneys and metabolism by the liver.
NOTE: ABOUT CLEARANCE
In planning detoxification strategy, it is important to know the contribution of each organ to total clearance.
For example, if a drug is 95% cleared by liver metabolism and only 5% cleared by renal excretion, even a dramatic increase in urinary concentration of the poison will have little effect on overall elimination.
NOTES:
Initial approach to the poisoned patient should be essentially similar in every case, irrespective of the toxin ingested, just as the initial approach to the trauma patient is the same irrespective of the mechanism of injury.
Initial approach to the poisoned patient:
This approach, which can be termed as routine poison management, essentially includes the following aspects:
- Stabilization: ABC’s
- Clinical Evaluation: Px history, Physical examination
- Decontamination: Prevention of absorption
- Specific antidote
- Removal of absorbed toxin: Enhancing excretion
- Supportive therapy: Monitoring adverse effects
- Detoxification: Preventive education
In the initial evaluation of a toxic patient, it is a must to remember that the most common cause of airway obstruction in the unconscious patient is ______.
Passive obstruction by the tongue
AIRWAYS
For many patients, simple positioning in the ____ is sufficient to move the flaccid tongue out of the airway.
AIRWAY
Lateral decubitus position
Also, it should be cleared of ____ or any other obstruction and an oral airway.
The head tilt chin lift or neck lift with jaw thrust may be the first maneuver on the unconscious poisoned patient followed by ______.
AIRWAY
- vomitus
- endotracheal intubation.
A soft, flexible tube is passed through the nose and into the trachea using a “blind” technique.
NASOTRACHEAL
The tube is passed through the mouth into the trachea under “direct” vision
OROTRACHEAL
DISADVANTAGES
● Perforation of the nasal mucosa, with epistaxis (nose bleed)
● Patient must be breathing spontaneously.
● Anatomically more difficult in infants because of anterior epiglottis.
ADVANTAGES
● May be performed in a conscious patient without requiring paralysis.
● Once placed, it is better tolerated than orotracheal tube.
NASOTRACHEAL
DISADVANTAGES
● frequently requires neuromuscular paralysis, creating risk of fatal respiratory arrest if intubation is unsuccessful
● requires neck manipulation, which may cause spinal cord injury after neck trauma
ADVANTAGES
● performed under direct vision, making accidental esophageal intubation unlikely
● insignificant risk of bleeding
● patient need not be breathing spontaneously
● higher success rate than that with nasotracheal route
OROTRACHEAL
The major cause of morbidity of poisoned and drugged patient is _______ difficulties
BREATHING
NOTES
Patients may have one or more of the following complications:
* Ventilatory failure,
* Hypoxia (low O2 level), or
* Bronchospasm
BREATHING
Breathing should be assessed by?
- Observation and
- Oximetry and, if in doubt,
- By measuring arterial blood gases (ABG)
Patients with respiratory insufficiency should be ____ and ____
intubated; mechanically ventilated
Administer supplemental oxygen as indicated based on arterial PO2. Intubation and assisted ventilation may be required.
If carbon monoxide poisoning is suspected, give 100% oxygen.
MANAGEMENT
Correct hypoxia
Obtain frequent sputum samples and initiate appropriate antibiotic therapy when there is little evidence of infection.
MANAGEMENT
Treat Pneumonia
There is no basis for prophylactic antibiotic treatment of aspiration- or _____.
MANAGEMENT
chemical-induced pneumonia
Although some physicians recommend _____ for chemical-induced pneumonia, there is little evidence of their benefit.
MANAGEMENT
corticosteroids
It may result from the following:
* Direct irritant injury from inhaled gases or pulmonary aspiration of petroleum distillates or stomach contents.
* Pharmacologic effects of toxins e.g. organophosphate or carbamate insecticides or beta-adrenergic blockers.
* Hypersensitivity or allergic reactions
Bronchospasm
Treatment of Bronchospasm
- Administer supplemental oxygen.
- Remove the patient from the source of exposure to any irritant gas or other offending agent.
- Immediately discontinue any beta-blocker treatment.
- Administer bronchodilators: Aerosolized ß2 stimulant (eg, albuterol 2.5 in nebulizer)
If this is not effective, and particularly for beta blocker induced wheezing, give _____, ___ mg/kg IV over ___ minutes.
This* is referring to Tx of Bronchospasm
aminophylline; 6; 30
For patients with bronchospasm and bronchorrhea caused by organophosphate or other anticholinesterase poisoning, give _____
atropine
The circulation should be assessed by continuous monitoring of the following:
- pulse rate,
- blood pressure,
- urinary output, and
- evaluation of peripheral perfusion
An intravenous line should be placed and blood drawn for _________ and other routine determinations.
serum glucose
___________ in the toxic patient must be addressed as quickly as possible in order to avoid the sequelae of shock
Hypotension
A fluid challenge of 100-200 mL of a crystalloid solution (10-20 mL/kg in pediatrics) is often given at this time while urine output is monitored (0.5-1 mL/kg/hour).
If the patient’s mental status is altered or if hypotension exists, four essentials are administered.
Thiamine, Oxygen, Naloxone, & Glucose
T-O-N-G
This can be especially effective in Px with limited glycogen stores (e.g. neonates and patients w/ cirrhosis)
Drugs to be utilized in toxic Px with altered mental status
25-50g of dextrose IV to reverse the effects of drug-induced hypoglycemia (adult) 1mL/kg and diluted 1:1 (child)
Extravasation into the extremity of this hyperosmolar solution can cause VOLKMANN’S contractures
Prevent WERNICKE’s encephalopathy
Drugs to be utilized in toxic Px with altered mental status
50-100mg of IV thiamine
a water soluble vitamin with low toxicity; rare anaphylactoid reactions have been reported
Specific opioid antagonist without any agonist properties
Drugs to be utilized in toxic Px with altered mental status
Initial dosage of Naloxone
Useful for carbon monoxide, hydrogen, sulfide, and asphyxiants
Drugs to be utilized in toxic Px with altered mental status
Oxygen, utilized in 100% concentration
While oxygen is antidotal for carbon monoxide intoxication, the only relative toxic contraindication is in paraquat intoxication (in that it can promote pulmonary fibrosis).
______ are due to intentional suicidal overdose by an adolescent or adult.
Acute poisoning
Childhood deaths due to ________ of a drug or toxic household product.
accidental ingestion
REMEMBER
Careful management of:
* Respiratory failure
* Hypotension
* Seizure
* Thermoregulatory disturbances
… will result in an improved survival of patients who reach the hospital alive
