Comparison of intraosseous pentobarbital administration and thoracic compression for euthanasia of anesthetized sparrows (Passer domesticus) and starlings (Sturnus vulgaris)

Abstract

OBJECTIVE To compare intraosseous pentobarbital treatment (IPT) and thoracic compression (TC) on time to circulatory arrest and an isoelectric electroencephalogram (EEG) in anesthetized passerine birds. ANIMALS 30 wild-caught adult birds (17 house sparrows [Passer domesticus] and 13 European starlings [Sturnus vulgaris]). PROCEDURES Birds were assigned to receive IPT or TC (n = 6/species/group). Birds were anesthetized, and carotid arterial pulses were monitored by Doppler methodology. Five subdermal braided-wire electrodes were used for EEG. Anesthetic depth was adjusted until a continuous EEG pattern was maintained, then euthanasia was performed. Times from initiation of euthanasia to cessation of carotid pulse and irreversible isoelectric EEG (indicators of death) were measured. Data (medians and first to third quartiles) were summarized and compared between groups within species. Necropsies were performed for all birds included in experiments and for another 6 birds euthanized under anesthesia by TC (4 sparrows and 1 starling) or IPT (1 sparrow). RESULTS Median time to isoelectric EEG did not differ significantly between treatment groups for sparrows (19.0 and 6.0 seconds for TC and IPT, respectively) or starlings (88.5 and 77.5 seconds for TC and IPT, respectively). Median times to cessation of pulse were significantly shorter for TC than for IPT in sparrows (0.0 vs 18.5 seconds) and starlings (9.5 vs 151.0 seconds). On necropsy, most (14/17) birds that underwent TC had grossly visible coelomic, pericardial, or perihepatic hemorrhage. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that TC might be an efficient euthanasia method for small birds. Digital pressure directly over the heart during TC obstructed venous return, causing rapid circulatory arrest, with rupture of the atria or vena cava in several birds. The authors propose that cardiac compression is a more accurate description than TC for this procedure.

Retrospective evaluation of cardiopulmonary arrest and resuscitation in hospitalized birds: 41 cases (2006–2019)

“…Additionally, because of their small size and delicate tissues, trauma can result from the compressions themselves. In a recent study that looked at the use of thoracic compressions in birds as a way to facilitate euthanasia, postmortem examination of 14 of 17 birds euthanized by this method had grossly visible internal hemorrhage 11 . The birds used in the study were of small size (sparrows and starlings), making it unclear if patient size impacts the degree of potential damage incurred versus the benefit of the compressions.…”

A proof‐of‐concept study evaluating cardiac compression techniques for cardiopulmonary resuscitation in laying hens (Gallus gallus)

“…8,9 The primary aim of the current study was to evaluate the effect of 3 different cardiac compression techniques, SC, SC with interposed caudal coelomic compressions (ICCC), and lateral compressions (LC), on directly measured arterial pressures and gross postmortem findings after compressions. [10][11][12] Because CPR research is uncommonly performed in chickens, additional information was also collected that could serve for future experimental studies. Specific, secondary, exploratory aims were to qualitatively assess the effect of IV epinephrine on arterial pressures during cardiac compressions and to evaluate the effectiveness of transthoracic defibrillation after cardiac compressions.…”

“…The primary aim of the current study was to evaluate the effect of 3 different cardiac compression techniques, SC, SC with interposed caudal coelomic compressions (ICCC), and lateral compressions (LC), on directly measured arterial pressures and gross postmortem findings after compressions 10–12 …”