Iohexol gastrointestinal transit times in cockatiels under sedation with intranasal midazolam by computed radiography

Abstract

This study used contrast radiography to evaluate gastrointestinal transit times in cockatiels (Nymphicus hollandicus) and investigated the sedative effects of intranasal midazolam in this species and its usefulness in facilitating the manual restraint required for radiographic studies. Twelve healthy adult cockatiels received intranasal midazolam at dose of 2 mg/kg, and iohexol at 15 ml/kg by crop gavage. Radiographic images were obtained before contrast administration, 3 minutes after and then each 10 minutes for 90 minutes. Sedation quality of the bird was evaluated during the radiographic study and assessed according to an adapted visual sedation scale. Three minutes after iohexol administration, the cervical oesophagus and the crop were filled in all birds. At the same time, the contrast medium reached the thoracic oesophagus, proventriculus, isthmus and ventriculus in most birds. In all cockatiels, median (range) transit times were 3 (3-10) minutes for proventriculus and ventriculus, 10 (10-40) minutes for small intestine and 45 (30-70) minutes for large intestine. The overall gastrointestinal transit time was 50 (30-90) minutes.Crop remained filled with iohexol throughout the study, while oesophagus and isthmus presented a pattern of contrast progression different from the other gastrointestinal segments. According to the visual sedation scale, cockatiels presented a moderate to intense muscular relaxation, and intranasal midazolam seems to be an appropriate sedation protocol for radiographic study. All cockatiels remained healthy after the study and presented clear and watery stools at least 12 hours after, due to gastrointestinal emptying.