Biomedical subjects
Publications and source records attributed to D B Brunson.
The decreased adaptability normally associated with aging animals is described. Anesthetic evaluation and management of these alterations can be successfully completed if wide variations in organ functions are not required of the patient by the surgeon or anesthetist.
Anesthetic management of the pleasure horse consists of the appropriate selection and administration of pre-anesthetic medications including anticholinergics, tranquilizers and narcotics followed by appropriate techniques of anesthetic induction. The anesthetic induction must vary somewhat for the pleasure horse practice since many of the procedures are completed on farms and ranches. As a result the inducing of anesthesia will frequently be with the same agent which will be used to maintain anesthesia. Noticeably will be the reduction and duration of anesthesia and surgical time. The induction of anesthesia will predominately be with ultra-short barbiturates alone or in combination with muscle relaxants or combinations of tranquilizers and dissociative anesthetics. Supplemental injections of intravenous agents or halothane, methoxyflurane or enflurane may be used to maintain anesthesia. Recoveries can be expected to vary according to the duration of anesthesia and the selection of agents that have been used. Anesthetic complications predominately consist of cardiopulmonary responses and those associated with recovery.
Anesthetic management of the pediatric patient is a challenge which can give rise to a most rewarding anesthetic management if one takes into consideration the normal physiological function of the pediatric patient. One should choose the appropriate medications which may safely be administered to an animal of this age. Control of anesthesia through the use of appropriate anesthetic equipment and the use of appropriate monitoring will aid safe management. The selection of adjunct medications can achieve control of complications and aid ultimate uncomplicated recovery.
Dogs given parenteral anticholinergic drugs have been thought to be at risk for development or exacerbation of elevated intraocular pressure (IOP). In a randomized, blinded, placebo-controlled study, we evaluated the effect of intramuscular glycopyrrolate (0.01 mg/kg) on pupil diameter and IOP in unanesthetized normal dogs. Treatment with glycopyrrolate did not change pupil diameter or IOP from baseline, nor were there differences between glycopyrrolate and saline-treated (control) dogs. In addition, the authors retrospectively reviewed the medical records of 2,828 dogs undergoing general anesthesia between April 1987 and September 1990 to determine if there was an association between parenteral anticholinergic medication and postanesthetic elevation in IOP. The authors also determined the frequency of bradycardia requiring anticholinergic therapy during anesthesia in dogs with glaucoma. Of the 2,828 cases reviewed, the records of 46 dogs coded for glaucoma were examined in detail. The 46 dogs underwent 62 episodes of anesthesia, with 23 episodes including exposure to an anticholinergic drug. An increase in IOP from preanesthetic to postanesthetic measurement occurred in three dogs. One of these dogs received anticholinergic medication for bradycardia during anesthesia. The postanesthetic elevation in IOP in this dog was probably not drug related. Preanesthetic anticholinergic administration did not affect the incidence of anticholinergic administration for bradycardia during the anesthetic episode. Anticholinergic therapy during anesthesia was more frequent when the preanesthetic medication included an opiate drug. These studies do not indicate an association between parenteral anticholinergic administration and elevations in IOP.
The use of butorphanol as an analgesic in a psittacine species was evaluated by determining its isoflurane-sparing effects. The Effective Dose 50 (ED50) of isoflurane was determined using a bracketing technique based on the purposeful movement elicited by pressure applied to a digit with a hemostat. The ED50 of isoflurane for 11 cockatoos (four greater sulfur crested, three lesser sulfur crested, and four citron crested) was determined to be 1.44 +/- 0.07%. After the administration of 1 mg/kg of butorphanol tartrate intramuscularly (IM), the ED50 was significantly (P < .05) decreased to 1.08 +/- 0.05%. Physiological variables that changed significantly included decreases in heart rate, tidal volume (Vt), inspiratory (Ti) and expiratory times (Te), and an increase in respiratory rate. No complications resulted because of these changes. Based on the results, butorphanol produces an isoflurane-sparing effect in cockatoos and has the potential to be a useful analgesic in psittacines.