Chapter 22 - Complications of inhalation anesthesia Flashcards
What effect does a decrease in body temperature have on the oxygen hemoglobin dissociation curve in anesthetized adult horses?
Shifts to left.
List two interventions for preventing hypothermia in anesthetized horses that are mentioned in the text.
Insulated padding
External heat sources
How much does the minimal alveolar concentration (MAC) decrease per degree Celsius drop in body temperature?
5%–8%
Why shivering postoperative may be observed?
Shivering during recovery
is commonly observed, and while there are likely other factors
causing this, hypothermia may contribute.
Why shivering is not desirable in the recovery?
Shivering can serve
to warm the patient but also increases oxygen consumption,
which may not be desirable.
What metabolic state, although rare, can be fatal in horses exposed to inhalation anesthetics?
Hyperthermia
What treatment is recommended for malignant hyperthermia, though it is challenging to administer?
Disconnect from machine
support with oxygen
ventilation
aactive cooling
Dantrolene sodium
What is the normal heart rate range in resting adult horses?
28–44 bpm
What heart rhythm condition is considered normal in athletic horses if it disappears during exercise?
Second-degree atrioventricular block
At what heart rate during inhalation anesthesia in adult horses is concern typically expressed?
Below 18–20 bpm
Which class of drugs potentiates bradyarrhythmias in horses during anesthesia?
α2-adrenoceptor agonists
In neonatal foals, what is primarily dependent on heart rate?
Cardiac output
Why are anticholinergics (such as atropine or hyoscine) not routinely used to treat bradycardia in horses?
Concern of ileus
What treatment should be considered if bradycardia is accompanied by hypotension and rhythm abnormalities?
anticholinergics (atropine)
Which anticholinergic has a more sustained effect on heart rate in horses, atropine or hyoscine?
Atropine
Which anticholinergic had longer-lasting effects on gastrointestinal motility, potentially causing colic?
Atropine
Which drug demonstrated improvement in cardiovascular variables when administered prior to xylazine?
Glycopyrrolate
What should be discontinued when using anticholinergics during anesthesia to avoid cardiac dysrhythmias?
Sympathomimetic drugs
Name two sympathomimetic drugs that may be used to treat bradycardia in horses.
Dobutamine
Ephedrine
Which electrolyte imbalance associated with hyperkalemic periodic paralysis warrants immediate treatment?
Hyperkalemia
What two treatments are used for hyperkalemia in horses with urinary tract obstruction or bladder rupture?
Intravenous calcium
Sodium bicarbonate
What nonspecific treatment can be administered for ventricular tachycardia during equine anesthesia?
Intravenous lidocaine
What condition may cause tachyarrhythmias in anesthetized, medically compromised horses?
Noxious stimulation
Which rhythm disturbance in anesthetized horses may compromise cardiovascular function depending on the ventricular rate?
Atrial fibrillation