Biomedical subjects
Publications and source records attributed to L S Pablo.
These two drugs, etomidate and Telazol, have different pharmacological properties. The good properties of these drugs should be employed in specific patients and procedures to be performed (Table 3). There is no ideal injectable agent available yet for clinical practice. This in itself makes practice quite interesting because of the continuous process of rationalizing and determining the best drug for a specific condition and patient.
Acid-base balance is a general term for the way in which the body maintains a relatively constant pH despite continuous production of metabolic end products and is fundamental to physiologic homeostasis. Disease states of animals lead to irregularities of body fluid, electrolyte, and acid-base balance. With the advent of less expensive, accurate, as well as portable blood gas and electrolyte analyzers, acid-base assessment has become a standard of care in veterinary medicine. It is important that the veterinary practitioner understand acid-base pathophysiology to assure successful treatment of these disease states. The purpose of this article is to provide a simple and concise description of traditional and modern acid-base data interpretation and assist the practitioner with application of these methods.
OBJECTIVE: To determine the median effective dose (ED50) of propofol required for induction of anesthesia in goats and the frequency of myoclonic activity and apnea associated with propofol administration. DESIGN: Clinical trial. ANIMALS: 28 healthy mature goats. PROCEDURE: ED50 was determined by use of the up-and-down method. The first goat was given 4 mg of propofol/kg (1.8 mg/lb) of body weight, i.v. Dose was increased by 25% for the next goat if endotracheal intubation was not possible and decreased by 20% if it was. For each subsequent goat, dose was determined on the basis of response of the previous goat. The ED50 was calculated by use of probit analysis. Induction time, frequency and duration of apnea, frequency of myoclonus, and other adverse effects were recorded. RESULTS: ED50 was determined to be 5.1 mg/kg (2.3 mg/lb). Mean (+/- SD) induction time was 23.2 +/- 4.7 seconds. Apnea was observed in 27 of 28 goats; mean (+/- SD) duration of apnea was 72.9 +/- 38.3 seconds. dose did not correlate without duration of apnea. Myoclonic activity was observed in 16 of 28 goats; frequency of myoclonus was not associated with dose. Cyanosis, regurgitation, and signs of pain during injection were not observed. CLINICAL IMPLICATIONS: Administration of propofol at 5.1 mg/kg (2.3 mg/lb), i.v., should permit endotracheal intubation in half of unpremedicated, healthy, mature goats. Myoclonus and apnea were associated with propofol administration.
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OBJECTIVE: Sedative, cardiorespiratory, and analgesic effects of intramuscular administration of medetomidine (40 micrograms/kg of body weight)-glycopyrrolate (0.01 mg/kg) and medetomidine (10 micrograms/kg)-butorphanol (0.2 mg/kg)-glycopyrrolate (0.01 mg/kg) combinations were compared. Additional evaluations were done on reversal of medetomidine, using atipamezole (200 micrograms/kg. IV), after 90 minutes of medetomidine-induced sedation. DESIGN: Crossover study, with each dog receiving each drug combination at 1-week intervals. ANIMALS: Six 2-year-old English hound-type dogs. PROCEDURE: Arterial blood pressure, ECG, respiratory rate, tidal volume, minute volume, arterial blood gas tensions, and serum biochemical variables were measured before, during, and after sedation. Analgesia was evaluated by needle prick on the skin and tail clamp. RESULTS: Heart rate decreased significantly from 100 beats/min to < 40 beats/min within 3 minutes of injection of medetomidine and medetomidine and butorphanol (MB). Mean arterial blood pressure in both groups were maintained above 100 mm of Hg throughout the recording period. There was no significant difference between medetomidine and MB in respiratory rate, tidal volume, and minute ventilation. Hypoxemia (PaO2 < 60 mm of Hg) was observed at 10 and 20 minutes in 2 dogs given MB. Atipamezole administration in the dogs given medetomidine significantly increased PaO2, and returned the values to baseline. Needle prick analgesia duration was longer in the medetomidine (80 +/- 7.7 minutes) than MB (56.0 +/- 19.2 minutes) group. Tail pinch analgesia was variable in both groups. Duration of lateral recumbency was longer after medetomidine (90 +/- 0 minutes) than MB (73.5 +/- 19.0 minutes). CONCLUSION: Medetomidine and MB were effective combination for mildly invasive procedures. CLINICAL RELEVANCE: MB induced a shorter period of analgesia and recumbency than did medetomidine.
We evaluated combinations of telazol, ketamine, and xylazine (TKX), telazol and xylazine (TX), telazol, xylazine, and xylazine (T2X), and ketamine and xylazine (KX) for chemical restraint and anesthesia induction in swine. Forty healthy mixed-breed pigs were randomly assigned to the four treatment groups with 10 pigs in each group. For TKX, TX, and T2X combinations, anesthetics were premixed by adding xylazine and ketamine, sterile water and xylazine, or xylazine alone directly into the telazol vial. For KX, anesthetic agents were drawn up separately, then mixed in the same syringe immediately before injection. All anesthetics were given as a single intramuscular injection. All four anesthetic combinations induced a rapid onset of sternal recumbency within 1.55 +/- 0.5 min and lateral recumbency within 2.27 +/- 0.6 min in pigs after intramuscular injection. There was no significant difference among treatments in these regards. The T2X combination induced a significantly longer duration of analgesia than did either TKX, TX, or KX. The T2X combination also induced a significantly longer duration of tolerance for endotracheal intubation and duration of lateral recumbency. Heart and respiratory rates were not significantly different among the four treatment groups. Vomiting was not observed in any of the treated pigs throughout the procedure. Recovery quality and duration from time of drug administration to recovery of pig walking unassisted were similar in three treatment groups but was shorter in KX-treated pigs. We concluded that all four anesthetic combinations were suitable for chemical restraint but that only TKX, TX, and T2X were suitable for anesthesia induction in pigs.(ABSTRACT TRUNCATED AT 250 WORDS)
The median effective dosage (ED50) of propofol for induction of anesthesia was determined in 25 dogs premedicated with acepromazine, 0.05 mg/kg of body weight, and in 35 unpremedicated dogs. The ED50 was found to be 2.2 mg/kg in premedicated dogs and was 3.8 mg/kg in unpremedicated dogs. The mean +/- SD total dosage of propofol required to induce anesthesia in premedicated animals was 2.8 +/- 0.5 mg/kg and was 4.7 +/- 1.3 mg/kg in unpremedicated animals. Signs of excitement were observed in 5 of the unpremedicated dogs, but in none of those that were premedicated.
Total strangulation obstruction of the caudal part of the jejunum was induced in 3 groups (each of 3 ponies) for 2, 4, and 6 hours. Coagulation tests which included blood platelet counts, prothrombin time, activated partial thromboplastin time, activated coagulation time, plasma fibrinogen level, and fibrin/fibrinogen degradation products assay were performed at specified time intervals for 1 week or until death of the experimental ponies. Another 3 ponies (sham-operated) were similarly treated, except that intestinal strangulation obstruction (ISO) was not induced. Necropsy was done on ponies that were euthanatized 9 days after the sampling period and on 2 ponies that died. Six hours of ISO resulted in severe ischemic damage to the intestines, characterized by hemorrhagic infarction, with or without perforation, in ponies that died, and total loss of mucosa with moderate to severe fibrosis of the intestinal wall in the surviving pony of this group. This damage was associated with significant coagulopathies, notably prolonged prothrombin time and activated partial thromboplastin time, decreased blood platelets count, and the presence of high levels of fibrin/fibrinogen degradation products (40 micrograms/ml). These laboratory findings are indicative of disseminated intravascular coagulation. In contrast, the jejunal segments of the ponies subjected to 2 and 4 hours of ISO were viable as revealed by histopathologic examination. There were no significant changes found in their coagulation profiles.(ABSTRACT TRUNCATED AT 250 WORDS)
Morphine (0.1 mg/kg) diluted with 0.9% saline to a volume of 0.13 mL/kg was administered into the epidural space at the lumbosacral junction in 10 halothane-anesthetized goats immediately before discontinuation of halothane. The same volume of 0.9% saline was given to control group of eight anesthetized goats. Both groups had undergone an orthopedic procedure that replaced the anterior cruciate ligament with a patellar tendon autograft. The appearance and unprovoked behavior of goats in the morphine group were significantly different (p < .05) from the saline groups. The goats in the morphine group were more sedate and struggled less during recovery. Epidural morphine did not produce respiratory depression or bloat during a 9 hour observation period. Heart rate, respiratory rate, and blood pressure (mean, systolic, and diastolic) of the morphine group did not differ from those of the control group.
The effects of intravenously administered atropine (0.2 mg/kg) and glycopyrrolate (0.01 mg/kg) on heart rate were studied in 10 conscious mature goats. In a drug cross-over fashion, either atropine, glycopyrrolate, or 0.9% saline solution was administered using the same volume (0.05 mL/kg). Atropine and glycopyrrolate caused a significant increase in heart rate (P < .05), whereas saline solution (0.09%) did not. The mean percent changes in heart rate from baseline were similar for atropine and glycopyrrolate up to 14 minutes after administration. Thereafter, glycopyrrolate had a significantly greater mean change in heart rate than atropine, ie, up to 29 minutes (P < .05). Within the atropine group, the mean percentage changes in heart rate became significantly lower compared with the initial increase (1 minute) starting at 11 minutes. For the glycopyrrolate group, the mean percent changes became significantly lower starting at 27 minutes. Glycopyrrolate and atropine had a mean percentage change in heart rate of greater than 1.0%, up to 31 and 22 minutes, respectively. At the doses used, glycopyrrolate had longer duration of action than atropine but the magnitude of increase was similar.