Page 1734 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 124: Toxicology in Adults 1203

elimination. Information provided by regional poison control centers
TABLE 124-18 Drugs Commonly Included in Urine Toxicology Screens 50
(Available in 2-3 Hours) (Continued) may be more accurate than advice provided by local EDs. The national
toll-free emergency phone number is 1-800-222-1222.
Propranolol
Propoxyphene DETOXIFICATION
Pseudoephedrine
Pyrilamine ■ GASTRIC EMPTYING
Quinine Historically gastric emptying has been attempted by gastric lavage (GL)
Strychnine or syrup of ipecac. There is no role for ipecac in the hospital setting as
it has no proven efficacy, it is associated with multiple risks, and it can
Temazepam
delay or decrease the effectiveness of other methods of decontamina-
Terpin hydrate tion. In the out-of-hospital setting, the recommended use of ipecac has
Trazodone been narrowed to an incredibly select patient population that meets the
following requirements: ipecac is not contraindicated (eg, the ingested
Triamterene
substance is not a corrosive, the substance will not cause altered mental
Trimethoprim status); the ingestion poses a sincere life threat; there is no alternative
Trimethobenzamide therapy available; the patient will not be able to reach a hospital in under
1 hour; ipecac can be given within 90 minutes of ingestion; and it will
Trimipramine
not adversely impact definitive therapy. 51,52
Tripelennamine GL can be attempted in the management of select ingestions. Like the
use of ipecac, risk-benefit analysis casts doubt as to the appropriateness
of GL in many situations. The risks associated with GL (including aspi-
Toxicologic screening of blood is generally not additive to compre- ration, arrhythmias, and stomach perforation) preclude its use in most
hensive urine testing, although rarely blood analysis is useful in acute patients. The indication for GL is recent ingestion (under 60 minutes) of
cases when the drug or toxin is not yet detectable in urine (particularly a highly toxic substance for which there is no reliable alternative therapy
49
in anuric or oliguric patients). Quantitative blood analysis of suspected (such as antidote). GL should not be performed when the toxin is no
53
drugs can be useful for diagnostic and therapeutic reasons, particularly longer expected to be present in the stomach. Examples include patients
in overdoses involving alcohols, acetaminophen, and salicylates. And a who have vomited extensively prior to admission, patients who present
strong argument can be made for checking acetaminophen and salicy- several hours after ingesting an agent that does not decrease gut motility
late levels in all cases of suspected intoxication given the subtle manifes- (eg, anticholinergics, opioids), and patients who have taken agents that
tations of early poisoning and the importance of targeted therapy. are readily absorbed from the gastrointestinal tract (eg, alcohols). In
cases of ingestion of a caustic liquid-like kerosene or its derivatives, GL
POISON CONTROL CENTERS should be avoided because of the risk of aspiration-induced lung injury.
To minimize risk, experienced personnel should perform GL lavage
Poison control centers provide 24-hour emergency and technical in a facility where resources are available to manage complications.
information by telephone to anyone concerned with drug overdose Nonintubated patients must be alert and have adequate pharyngeal and
or toxic ingestion. These centers are staffed by nurses, pharmacists, laryngeal protective reflexes. In semicomatose patients, GL should be
pharmacologists, and physicians trained in clinical toxicology. They performed after intubation. Intubation for the sole purpose of GL is
provide information regarding substance identification, drug interac- reasonable only if there is a high likelihood that a highly lethal agent
tions, adverse drug reactions, and management of poisoned patients. remains in the stomach.
These centers maintain current references and information about toxins Prior to inserting a large-bore orogastric tube (Ewald tube), the
and drugs specific to certain areas, including information about street mouth should be inspected for foreign material and equipment should
drug activity. be readied for suctioning. Large gastric tubes (37F-40F) are necessary to
Poison control center consultation is strongly advised to help deter- facilitate removal of gastric debris. Once the tube has been passed with
mine appropriate laboratory testing, patient disposition, and treatment, the help of patient swallowing, proper position is confirmed by aspirat-
including the need for a specific antidote or method to enhance drug ing acidic stomach contents and auscultating the left upper abdominal
quadrant during insufflation of air. Stomach contents should be retained
for analysis. In the adult patient, lavage is performed by instilling 200-mL
aliquots of warmed tap water or normal saline until there is clearing of
TABLE 124-19 Drugs/Toxins Not Commonly Included in Toxicology Screens
aspirated fluid. In children, normal saline is preferred, because tap water
Antiarrhythmic agents has been associated with severe hyponatremia. In adults, tap water is
53
Bromide preferred over normal saline because it avoids unnecessary salt loading,
Cyanide and neither irrigant significantly alters blood cell concentrations or elec-
trolyte concentrations. After clearing, the Ewald tube may be replaced
54
Digitalis
by a nasogastric tube for intermittent suctioning and/or administration
Ethylene glycol of activated charcoal.
Hypoglycemic agents ■
Lithium ACTIVATED CHARCOAL
Charcoal is a by-product of the combustion of various organic com-
Lysergic acid diethylamide (LSD)
pounds such as wood, coconut parts, bone, sucrose, rice, and starch. It
Methanol is activated by removing materials previously absorbed by a process that
Monoamine oxidase inhibitors involves steam heating and chemical treatment, thereby increasing the
Serotonin reuptake inhibitors surface area available for absorption. The result is a powerful nonspe-
cific adsorbent that binds intraluminal drugs and interferes with their
Theophylline
absorption. 55

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