Page 956 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

908 SECTION | XIV Poisonous Plants

VetBooks.ir (20% solution), 4 mL/kg BW, strictly intravenously, and with the administration of lactated Ringer’s solution or
plasma expanders.
sodium nitrite (10% solution), 2 mL/kg BW, strictly
Cardiac activity can be aided by the application of
intravenously.
closed-chest cardiac massage for immediate cardiovascu-
lar support, but the administration of calcium gluconate,
SUPPORTIVE THERAPY
infused slowly intravenously, can stimulate cardiac activ-
Treatment of most cases of poisoning is largely supportive. ity in most instances. This agent is also a good nonspe-
The aim of the supportive measures is to preserve the vital cific treatment of many toxicities.
organ function until the poison is eliminated from the body Control of acid-base balance problems is primarily a
and the patient resumes normal physiological functions, matter of physiologically maintaining an animal in a
including control of body temperature, maintenance of car- homeostatic condition. The most common acid-base dis-
diopulmonary function and renal system, control of acid- turbance seen is metabolic acidosis, but alkalosis may
base status, alleviation of pain and control of CNS effects also occur in cases of poisoning. In correcting acidosis
with proper care for coma, seizures, hypotension, arrhyth- not of respiratory origin, sodium bicarbonate intrave-
mias, hypoxia, and acute renal failure. If seizures occur, nously is the drug of choice. Caution must be exercised
diazepam, phenobarbital or pentobarbital may be used; an with alkalinizing agents to avoid the induction of alkalo-
initial diazepam dose of 0.5 mg/kg BW i.v. may be sis. For initial therapy, it is usually sufficient to adminis-
repeated every 20 min up to three times. If diazepam is not ter 0.9% NaCl (physiologic saline) intravenously,
sufficiently effective in small animals, use pentobarbital at followed by oral administration of divided doses of
6 mg/kg BW i.v. or pentobarbital at 24 29 mg/kg BW i.v. ammonium chloride.
(Dalefield and Oehme, 2006). Body temperature should be Control of pain with a minimal dose of morphine or
monitored. Hypothermia can be controlled with a circulat- meperidine is used in animals. Management of CNS dis-
ing hot water blanket and by keeping the animal in a warm orders in cases of intoxication is complex. Therapy
and draft-free cage. Hyperthermia is treated with ice bags, depends on the presence of CNS depression or hyperac-
cold water baths, and enemas. It is vitally important that tivity. Either disorder can easily be reversed to the
the animal’s body temperature be constantly monitored to extreme by overzealous treatment. CNS depression can
prevent overcorrection. also be considered with respiratory depression because
Respiratory support requires an adequate patent air- the management of the two conditions is very similar.
way, using a cuffed endotracheal tube in an unconscious Although the intravenous administration of analeptic
animal or by performing a tracheostomy under local anes- agents, such as doxapram, is reported to be efficacious,
thesia. A respirator is of great value, or an anesthesia their actions are short-lived, and CNS depression returns
machine may be utilized with manual compression of the if the animal is not monitored continuously. Bemegride is
bag. Administer supplemental 100% oxygen. also occasionally used to stimulate the respiratory centers
It is more appropriate to insert an endotracheal tube in the medulla. Analeptics may also induce convulsions.
and provide positive pressure ventilation if needed. A Cases of CNS hyperactivity, including convulsions,
patient that is depressed sufficiently to require respiratory can be managed by the administration of CNS depressants
assistance must be continuously monitored. All uncon- or tranquilizers. Pentobarbital sodium, phenobarbital, phe-
scious or shock patients require intubation. nytoin, and primidone are the agents of choice for convul-
Be prepared to supply respiratory support. Although sions and hyperactivity; care must be taken, however,
analeptic agents such as doxapram used in respiratory because a respiratory depressing dose may be required to
depression may provide immediate support, the effect is alleviate all adverse signs. Inhalant anesthetics are excel-
transient and cannot be relied on to sustain a pet free lent for long-term management of CNS hyperactivity.
from poisoning. Doxapram 1 10 mg/kg BW intrave- Central acting skeletal muscle relaxants and minor tran-
nously may cause seizures if administered in overdoses quilizers (methocarbamol, glyceryl guaiacolate, and diaz-
(70 75 times the therapeutic dose in healthy animals) epam) are also used for convulsant intoxicants. The
(Dalefield and Oehme, 2006). animal should be placed in a quiet, dark room to reduce
Cardiovascular support requires the presence of ade- excitation due to auditory or visual stimuli.
quate circulating blood volume, cardiac function, tissue
perfusion, and acid-base balance. Blood volume and car-
diac activity are of most immediate concern. CONCLUDING REMARKS AND FUTURE
In the presence of hypovolemia due to loss of both DIRECTIONS
cells and volume, whole blood is needed. A sufficient
quantity of whole blood should be given to raise the Compared to North American and African flora,
packed volume to 75% of the animal’s estimated normal European flora have fewer dangerous species; however
level. Hypovolemia due to fluid loss alone can be treated the number of plant poisonings is considerable. Local