Objective – To establish a reference interval for intra-abdominal pressure (IAP) measured by urinary bladder catheterization in normal cats and determine if IAP is affected by observer variation, volume of saline instillation before measurement, or subject variables of gender, positioning, body condition score, and sedation.
Design – Prospective experimental study.
Setting – Private referral center.
Animals – Twenty healthy adult cats.
Interventions – Sedation with butorphanol, midazolam, and propofol for catheterization of the urinary bladder and measurement of IAP.
Measurements and Main Results – A 5-Fr red rubber urinary catheter was placed under sedation, and IAP was determined using a water manometer with the cats in right lateral and sternal recumbency. Three readings were taken in each position by 2 observers. The cats were allowed to recover with the urinary catheter in place, and IAP was measured in each cat while they were awake in right lateral and sternal recumbency.
Conclusions – In this population of clinically healthy cats, median (interquartile range) IAP taken over all measurements was 7.00 cm H2O (5.23–8.83 cm H2O). There was no statistical difference between observers or subject gender. Factors associated with a statistically significant increase in IAP were right lateral compared with sternal recumbency (P=0.002), being awake compared with sedated (P<0.001), having a higher body condition score (P=0.01 and 0.001), instillation of a higher volume of saline into the bladder for measurement (P<0.001), and struggling during awake measurements (P<0.001).