Robert R. Paddleford

Alpha2 Agonists and Antagonists

This article discusses the use of the alpha 2 agonists in the dog and cat. A review of alpha 2 adrenoceptor activity is presented. The alpha 2 agonists xylazine and medetomidine are discussed. The physiological effects, clinical uses, and precautions and contradictions for each drug are presented. The use of the alpha 2 antagonists, yohimbine and atipamezole, are also discussed.

Advantages and guidelines for mask induction.

Inhalational agents with low blood/gas solubilities (halothane, isoflurane, and nitrous oxide) are preferred for mask induction. A gradual step up in the vaporizer concentration is the recommended induction method because it is generally smoother and safer than the crash induction technique.

Anesthesia and Analgesia in Dogs, Cats, and Ferrets

Publisher Summary Customizing anesthetic techniques to be used for each research model or protocol is possible through the application of this information from the accumulation of clinical experience with dogs, cats, and ferrets as domestic pets. The state or condition referred to as anesthesia, or particularly general anesthesia, includes the component conditions of unconsciousness, amnesia, lack of sensation to potentially noxious stimuli, and muscle relaxation. The characteristics of each of these constituent components of general anesthesia are affected by the choice of anesthetics and anesthetic techniques. Anesthetic protocols should include consideration of sedation; pharmacological restraint (occasionally appropriate as an alternative to general anesthesia); induction and maintenance of general anesthesia; perioperative physiological management or support; anesthetic monitoring and plans for responding to anticipated physiological changes; and, in chronic studies, the recovery from anesthesia and postoperative care. The safety that often has been associated with inhalant, as opposed to injectable anesthetics, is largely due to the provision of supplemental oxygen as the carrier gas for the volatile anesthetics. Endotracheal intubation and administration of supplementary oxygen can easily be incorporated into injectable anesthetic techniques and can add substantial safety. If anesthesia is deep enough to allow for placement of an endotracheal tube, then the animal is no longer able to protect its airway from the aspiration of regurgitated or foreign material. Although not all anesthetized animals will require supplementary oxygen administration, most animals should be considered for this level of support during anesthesia and surgery.

MANAGEMENT OF GERIATRIC PATIENTS : A COMMON OCCURRENCE

The anesthetic and perioperative care of geriatric animals requires increased vigilance and support. The margin of acceptable physiological variation is probably more narrow than in younger patients. Underlying disease, which is often subclinical, influences metabolism and recovery from anesthetics and also predisposes the patients to adverse outcome. Limited respiratory and cardiovascular reserve diminishes the ability of many older patients to meet the challenges of anesthesia and surgery or other stressful medical procedures. The psychological, as well as physiological, stress of hospitalization is increased in many geriatric patients.