Page 620 - ACCCN's Critical Care Nursing

Emergency Presentations 597

raises the level of suspicion of a poisoning, especially if MANAGEMENT: PREVENTING
there is no history of previous signs or symptoms that TOXIN ABSORPTION
suggest another cause. If a patient presents with a history Initial and ongoing care of a victim follows three
of poisoning, the benefits and risks of treatment should principles: 104
be considered and therapy given if there is any doubt. 105,107
1. preventing further absorption of the toxin
Suspected Toxin 2. enhancing elimination of absorbed toxin from the
body
Rescue personnel, family or friends should bring any con-
tainer, plant product or suspected toxin with the patient 3. preventing complications by providing symptom-
to the hospital, as long as the substance presents no risk atic or specific treatments, including psychiatric
of contamination to the person retrieving it. If multiple management.
plants are growing together, a sample of each should be Ingested poisons are best removed while still in the upper
included. A child’s play area should be inspected for pos- gastrointestinal tract when possible. Emesis and gastric
sible sources of toxins. 107,108 lavage were utilised in the past to empty the stomach,
although a significant body of evidence now suggests that
Time of Poisoning these approaches are relatively ineffective and effective-
ness decreases rapidly after 1 hour. 107,108,110 Both the
History includes time of exposure, onset of symptoms
and time since treatment began. If the toxin was ingested, patient and substance should be evaluated for appropri-
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determine the time since the last meal or alcohol con- ateness of gastric emptying. The patient’s consciousness
sumption. Alcohol is the most common drug taken with level, gag reflex and ability to vomit while protecting the
other intentional self-poisonings, can potentiate a range airway from aspiration is considered. Any central nervous
of medication effects and increase the incidence of vomit- system depressants are capable of obtunding the protec-
ing and potential aspiration. 108,110,112 Poisonings in chil- tive gag or cough reflex. If the ingested substance has a
dren tend to occur most often just prior to mealtimes, rapid onset of action (e.g. benzodiazepines), it is safer to
when they are hungry. Adults may take substances late in avoid emetics because of the risk of a sudden fall in the
the evening, fall asleep and be found several hours later. 104 level of consciousness.

Physical Assessment Ingested Poisons
Evaluate the substance ingested to determine whether
A thorough assessment may provide clues with an uncon-
scious, uncooperative or suspicious presentation. Assess gastric emptying is appropriate. Physical properties of a
for respiratory effort, skin colour, pupil size and reactivity, drug may make it more responsive to a particular type of
reflexes and general status. Auscultation of the lung fields, gastric emptying. For example, tricyclic antidepressants
the apical pulse and bowel sounds provide a baseline for tend to reenter the stomach acid after absorption into the
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further assessment and clues to current problems. Check serum. Also consider the effects of substances on tissue.
the blood pressure as often as necessary to determine Corrosives, such as acids, alkalis and iron supplements,
cardiovascular stability. Percuss the thorax and abdomen produce irritation and tissue breakdown when in contact
to detect accumulations of fluid or air. 108,111 Needle marks, with the skin or mucous membranes. Recognition is
pill fragments, uneaten leaves or berries, or drug para- important, as therapy may cause further injury. Emesis
phernalia assist in a diagnosis. 108,111 The presence of pres- could be contraindicated, and a lavage tube may trauma-
sure areas on the skin may indicate how long the patient tise injured tissue. Waiting for emesis also causes further
has been unresponsive. Any odours are important to delay in definitive treatment. Other substances have
note; an oily-garlicky smell may be due to pesticides; natural emetic qualities if taken in sufficient doses (e.g.
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other odours may indicate chronic medical disorders (e.g. hand soaps and liquid soap detergents).
fruity odour with diabetic ketoacidosis) or neglect of per- Evaluate other substances on an individual basis. Most
sonal hygiene. 112 petroleum distillates (e.g. furniture polish, cleaning
fluids) present a greater hazard for chemical pneumonitis
Diagnostics than a systemic intoxication. Even very small amounts
114
Toxicology screens include analysis of serum and urine can quickly disperse over the lung surface if accidentally
to determine the presence and amount of a substance. introduced into the trachea. Avoid emesis or lavage when
114
Laboratory levels are helpful but are considered in rela- the chance of aspiration is high. There are situations,
tion to the nature of the substance and its rate of metabo- however, when the amount, character or additional
lism. Certain substances are sequestered in fatty tissues chemicals present make it necessary to remove the
or bound to serum proteins, and may be present with ingested substance from the stomach.
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a misleadingly low serum level. Serum electrolytes, Therapy can be based on the reported amount taken or
non-electrolytes, osmolality, arterial blood gases and time since ingestion. Time since ingestion is important to
urine electrolytes are used to determine a patient’s overall rule out the benefit of therapy, as the stomach tends to
status or response to therapy. Continuous cardiac moni- empty its contents after 1 hour unless the ingested sub-
toring supplemented with a 12-lead ECG or invasive stance slows gastric motility (e.g. narcotics slow peristalsis
monitoring devices may be required to guide symptom- and may be found in the stomach several hours after
atic care. 107,108,110 ingestion). A patient may also under-report the dosage
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