Ultrasound-Guided Cystocentesis in Dogs and Cats - Epidemiological Study of Risk Factors and Complications
Authors: Muehlbauer Eloisa , Saldanha André Ferreira , Ueno Gil Elaine Mayume , Sombrio Marina Silvestre , Ribeiro Sales Bianca , Duque Juan Carlos Moreno , Rodrigues Froes Tilde 
Published: December 2024

Background: Cystocentesis is a percutaneous aspiration of urine directly from the urinary bladder. It is a routine procedure in veterinary medicine for laboratory urine evaluation and bladder decompression in dogs and cats. Although considered simple and causing minimal discomfort, it remains invasive with potential risks of complications. These complications include bladder rupture leading to abdominal contamination and peritonitis, as well as aortic and vena cava laceration, abdominal wall injuries, seizures, and syncope. There is a scarcity of epidemiological studies assessing risk factors and associated complications and, in this context, we aimed in this study to correlate risk factors with the main complications of ultrasound-guided cystocentesis in dogs and cats.Materials, Methods & Results: It was a prospective and multicentric study involving 410 animals (267 dogs and 143 cats) with clinical indications for cystocentesis. The animals were positioned in dorsal recumbency and restrained by either owner, technical staff, or both. Temperament (calm/docile or agitated/difficult to restrain), along with various data such as species, breed, weight, age, sex, needle length, number of attempts, volume of urine collected, ultrasound findings, and any complications during the procedure, were recorded. Animals were categorized into 2 groups, group with complications (GCI) and group without complications (GSI). Of these, 31 animals (8%) experienced complications after ultrasound-guided urine collection. Compared to agitated animals, there was an 86% reduction in the likelihood of complications in animals classified as calm and easy to handle. Repeated urine collection attempts increased the chance of complications by 110%, even in calm individuals, and each additional millimeter of needle length used for puncture increased the possibility of complications by 30%. Agitated animals restrained by their owner had a 71% chance of complications compared to 7% when they were restrained by the technical staff.Discussion: The data reveals a low probability of complications (8%) during cystocentesis, but it is crucial to consider the risk factors for each patient, as catastrophic outcomes can occur. Interestingly, older animals had a 14% lower likelihood of complications, likely due to increased adaptability and calmness. Proper restraint by a specialized team significantly reduced complication risks, even for agitated animals, which is a noteworthy finding not previously reported. Repeated attempts at urine collection increased complication risks, as did using longer needles, which could damage tissues and puncture vessels near the bladder. In this study, data regarding bladder filling was not included, potentially impacting the results and procedure difficulty. The absence of behavioral assessment scales to measure agitation or anxiety resulted in subjective assessments, lacking standardization. Ultrasound guidance during cystocentesis is valuable to minimize risks and should be considered. While the probability of complications is low, owners should be informed of potential risks, and sedation may be necessary for very agitated or uncooperative animals. In conclusion, ultrasound-guided cystocentesis resulted in complications in approximately 8% of cases. These complications can be significant, such as puncturing large vessels and rupturing the urinary bladder.Keywords: cystocentesis, ultrasound, canine, feline, complication, epidemiology.