Cardiopulmonary effects of butorphanol in sevoflurane‐anesthetized guineafowl (Numida meleagris)

ObjectiveTo evaluate the cardiopulmonary changes induced by intravenous butorphanol administration in guineafowl anesthetized with sevoflurane.Study designProspective experimental trial.AnimalsEight adult guineafowl (Numida meleagris) weighing 1.61 ± 0.49 kg were used for the study.MethodsBirds were anesthetized with sevoflurane and allowed to breathe spontaneously. After endotracheal intubation, end-tidal sevoflurane was adjusted to 1.0 individual sevoflurane MAC that was previously determined in triplicate using a standard bracketing technique. The brachial artery was catheterized for direct pressure measurement and blood sampling. Heart rate and rhythm were monitored by electrocardiography and respiratory rate was recorded. Baseline data were recorded 30 minutes after induction. Then, end-tidal sevoflurane was adjusted to 0.8 individual MAC and after 15 minutes physiologic variables were measured again. Subsequently, butorphanol (4 mg kg^?1) was administered intravenously over 10 seconds and physiologic responses were recorded at 1, 5, 10, 15, 20, 30 and 45 minutes after administration.ResultsButorphanol administration was associated with arrhythmias in all birds, including second-degree atrioventricular block, sinus arrest, ventricular and supraventricular tachycardia and ventricular premature complexes. Heart rate and arterial blood pressures decreased significantly 1 minute after butorphanol administration. Two birds developed severe hypotension, apnea and ventricular fibrillation 5 minutes after administration, and one died.Conclusions and clinical relevanceThe butorphanol dose (4 mg kg^?1) that produces clinically relevant sevoflurane MAC reduction in guineafowl caused severe adverse cardiopulmonary effects in two birds and was considered unsafe under the conditions used in this study.     

Energetic Charged-Particle Phenomena in the Jovian Magnetosphere: First Results from the Ulysses COSPIN Collaboration

The Ulysses spacecraft made the first exploration of the region of Jupiter's magnetosphere at high Jovigraphic latitudes ( approximately 37 degrees south) on the dusk side and reached higher magnetic latitudes ( approximately 49 degrees north) on the day side than any previous mission to Jupiter. The cosmic and solar particle investigations (COSPIN) instrumentation achieved a remarkably well integrated set of observations of energetic charged particles in the energy ranges of approximately 1 to 170 megaelectron volts for electrons and 0.3 to 20 megaelectron volts for protons and heavier nuclei. The new findings include (i) an apparent polar cap region in the northern hemisphere in which energetic charged particles following Jovian magnetic field lines may have direct access to the interplanetary medium, (ii) high-energy electron bursts (rise times approximately 17 megaelectron volts) on the dusk side that are apparently associated with field-aligned currents and radio burst emissions, (iii) persistence of the global 10-hour relativistic electron "clock" phenomenon throughout Jupiter's magnetosphere, (iv) on the basis of charged-particle measurements, apparent dragging of magnetic field lines at large radii in the dusk sector toward the tail, and (v) consistent outflow of megaelectron volt electrons and large-scale departures from corotation for nucleons.     

Effect of pre-medication on gastroduodenoscopy in isoflurane-anesthetized cats

The pre‐medicant chosen may influence the ease with which gastroduodenoscopy (GD) is performed. The purpose of this study was to evaluate the relative ease of GD in cats under ketamine and isoflurane anesthesia after IM injection of hydromorphone (H, 0.1 mg kg^?1), hydromorphone plus glycopyrrolate (HG, 0.1 mg kg^?1 (H), 0.01 mg kg^?1 (G)), medetomidine (M, 0.03 mg kg^?1), or butorphanol (B, 0.4 mg kg^?1). Eight cats were assigned randomly to receive each treatment in a cross‐over design with at least 7 days between treatments. Twenty minutes after pre‐medication, medetomidine produced greater (p = 0.001) sedation than the other treatments when assessed, using a subjective ordinal scale. The cats were injected with ketamine (10 mg kg^?1 IM), orotracheally intubated, connected to a pediatric circle breathing system, and allowed to spontaneously breathe isoflurane in oxygen. Once end‐tidal isoflurane concentration was stable at 1.4% for 15 minutes, endoscopy was started. A single endoscopist (REG), who was unaware of the treatment used, performed all endoscopies. The endoscopist scored the difficulty of endoscopy subjectively (0–3). The significance of differences between treatments was evaluated using Friedman's test. Time for entering the stomach was 9.4 (4.7–15.9) (median (minimum–maximum)), 6.6 (5.2–11.7), 8.4 (6.3–16.5), and 7.7 (5.1–14.7) seconds and for entering the duodenum from the stomach was 20.5 (13.8–40.9), 18.2 (10.3–39.8), 20.2 (16.2–119.5), and 22.2 (11.8–83.8) seconds for H, HG, M, and B treatments, respectively. There were no significant differences in the time for, or difficulty of, endoscopy. We conclude that any of these drugs can be used satisfactorily at the doses and combinations tested to pre‐medicate cats prior to general anesthesia for GD.