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1088 Defibrillation, Electrical

When the administration is complete, Pearls • Concentrated (>3%) hydrogen peroxide can
the orogastric tube must be occluded • Emetics are usually most effective within potentially cause severe bloody gastroenteritis
VetBooks.ir Postprocedure cases, emesis may be effective even after • On average, dogs vomit 3-4 times from
2-3 hours after the exposure, but in some
when removing it to reduce the risk of
and air embolism.
aspiration.
hydrogen peroxide and apomorphine, and
that time frame. Substances that coalesce
• After emesis, withhold food and water for to form bezoars (e.g., chocolate or chewable 48%-52% of the ingested toxicant is recov-
ered in the vomitus.
medications) or time-released medications
several hours (or longer if clinically indi- may be appropriately addressed with emesis ○ Duration of emesis in dogs is 42 and
cated), and monitor for signs of aspiration. induced > 3 hours after ingestion. 29 minutes after onset with hydrogen
Fluid therapy as indicated for dehydration • Xylazine is an effective emetic in 42% peroxide and apomorphine, respectively.
and serum electrolyte disturbances of cats. Dexmedetomidine may be more ○ Persistent mild nausea, hypersalivation,
• After gastric lavage, monitor body tem- effective at the labeled dosage (40 mcg/kg and lethargy occur in 3% and 14% of dogs
perature and for signs of aspiration. Fluid IM), with vomiting expected within 2-3 given hydrogen peroxide or apomorphine,
therapy as indicated for dehydration and minutes of IM administration. The drug respectively. Administration of gastropro-
serum electrolyte disturbances can be reversed with atipamezole immedi- tectants should be considered.
• After activated charcoal administration, ately after vomiting so sedation does not • Apomorphine is poorly effective as an emetic
monitor serum sodium (for hypernatremia) persist. in cats.
and for signs of aspiration. • Some dogs will drink 3% hydrogen peroxide
voluntarily when it is mixed with a small SUGGESTED READING
Alternatives and Their amount (5 mL, 1 teaspoon) of ice cream, DeClementi C: Prevention and treatment of poison-
Relative Merits peanut butter, chicken broth, or milk/ ing. In Gupta RC, editor: Veterinary toxicology:
Because decontamination procedures are not yogurt. This may be especially helpful for basic and clinical principles, ed 2, London, 2012,
without risks, the clinician must decide in recent ingestions by patients that are still Academic Press, pp 1361-1368.
each case if the possible clinical outcome of asymptomatic and at home. AUTHOR: Camille DeClementi, VMD, DABT, DABVT
an exposure to a toxicant warrants performing • Expired hydrogen peroxide may not effec- EDITORS: Leah A. Cohn, DVM, PhD, DACVIM; Tina
the procedure. tively induce emesis. Wismer, DVM, MS, DABVT, DABT

Defibrillation, Electrical Bonus Material
Online

Difficulty level: ♦♦ • Defibrillator, monophasic or biphasic ventricular fibrillation results in a 10%
• Defibrillation gel decreased rate of hospital discharge.
Overview and Goal • Electrical outlet • Poor body contact with paddles/gel
Administration of a controlled electrical shock • Use of the wrong gel; ultrasound gel is not
to a fibrillating heart depolarizes the heart Anticipated Time an appropriate option because it does not
muscle, places the myocytes into a transient 1-10 minutes have effective conduction.
refractory period, and stops the uncoordinated
muscle activity. Restoration of a normal sinus Preparation: Important Procedure
rhythm or asystole is the desired outcome. Checkpoints • CPR is underway according to RECOVER
• CPR has begun guidelines (p. 1077).
Indications • ECG demonstrates ventricular fibrillation • Ventricular fibrillation is noted on ECG.
• Ventricular fibrillation ○ Patternless electrical activity with rapid ○ If fibrillation has been present for < 4
• Pulseless ventricular tachycardia undulations that may be coarse or fine minutes, immediately defibrillate.
○ No synchronized activity/QRS complexes ○ If ventricular fibrillation is suspected
Contraindications seen to have been ongoing for > 4 minutes,
• Any rhythm other than ventricular fibrillation perform a 2-minute cycle of CPR before
or pulseless ventricular tachycardia Possible Complications and the defibrillation attempt.
○ Coarse or fine fibrillation may be present. Common Errors to Avoid • Defibrillation gel is applied to both
○ Patients with a fibrillation rhythm who • Inadvertent shock delivered to bystanders in paddles.
are unconscious and do not have palpable direct or indirect contact with the patient. • Energy requirement is determined/chosen.
pulses This can have dangerous consequences and For external defibrillation, use
○ The electrocardiographic (ECG) rhythm lead to cardiac arrest. ○ Biphasic defibrillator (preferred) 2-4 J/kg
should be checked in more than one lead • Burn to patient’s body wall or damage to ○ Monophasic defibrillator 4-6 J/kg
because fine fibrillation may be difficult cardiac myocytes • Patient is rotated into dorsal recumbency
to see in some leads. • Fire (foam or Plexiglas cradle ideal), and the
• An inability to electrically isolate the patient ○ Oxygen should be disconnected from the paddles are firmly placed directly over the
from its surroundings patient before shock delivery. heart on opposite sides of the chest.
○ Alcohol should not be used on ECG leads • The person discharging the shock must
Equipment, Anesthesia or elsewhere on patient. determine that no one is in contact with the
• ECG monitor • Delayed defibrillation patient, table, or any fluids/gels contacting
• Equipment necessary for cardiopulmonary ○ The likelihood of a successful defibril- the patient or table.
resuscitation (CPR) (e.g., endotracheal [ET] lation decreases rapidly with persistent ○ After confirming this, a statement of ALL
tube, drugs, monitoring devices [p. 1077]) fibrillation. In people, every minute of CLEAR should be made.

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