Determination and validation of volume to be instilled for standardized intra-abdominal pressure measurement in dogs.

OBJECTIVES: The objectives of this study were to determine (1) most appropriate volume of saline to be infused into the bladder prior to intra-abdominal pressure (IAP) measurement, (2) to determine if a difference exists between IAP measurements before and after abdominal surgery, and (3) to assess the variability in IAP measurements associated with different saline volumes. DESIGN: Prospective study. SETTING: University teaching hospital. ANIMALS: Fifteen female research dogs, 7 undergoing ovariohysterectomy (OHE), and 8 undergoing laparoscopy. INTERVENTIONS: All dogs had urinary catheters placed and 4 consecutive IAP measurements measured using a different volume of instilled saline (0.25, 0.5, 1, and 2 mL/kg) at baseline. Measurements were repeated intraoperatively in laparoscopy dogs and postoperatively in OHE dogs. MEASUREMENTS AND MAIN RESULTS: For both groups of dogs, the volume infused into the bladder significantly affected IAP measurement. An instilled volume of 1 mL/kg of saline produced the best correlation (R(2) = 0.44, P = 0.04) between IAP measurement and laparoscopic insufflator pressure. The mean (±SD) preoperative IAP (cmH2 O) using 1 mL/kg instilled saline was 7.9 ± 1.4 and 9.6 ±1.9 for laparoscopy and OHE dogs, respectively. There was no difference in IAP before and after surgery in the dogs undergoing an OHE (P = 0.58). The volume of saline instilled into the bladder significantly affected the IAP (P = 0.0028). CONCLUSIONS: One milliliter per kilogram instilled saline is recommended for standardized IAP pressure measurement in dogs. IAP in clinically normal dogs was not affected by abdominal surgery.

Comparison of routine urinalysis and urine Gram stain for detection of bacteriuria in dogs.

OBJECTIVE: To determine the utility of performing urine Gram stain for detection of bacteriuria compared to routine urine sediment examination and bacterial aerobic urine culture. DESIGN: Prospective, observational study. SETTING: University teaching hospital. ANIMALS: Urine samples acquired via cystocentesis through convenience sampling from 103 dogs presenting to a tertiary referral institution. INTERVENTIONS: All samples underwent routine urinalysis, including sediment examination, as well as urine Gram stain and quantitative bacterial aerobic urine culture. MEASUREMENTS AND MAIN RESULTS: The urine Gram stain demonstrated improved sensitivity (96% versus 76%), specificity (100% versus 77%), positive predictive value (100% versus 83%), and negative predictive value (93% versus 69%) when identifying bacteriuria, compared to routine urine sediment examination. CONCLUSIONS: The urine Gram stain is highly sensitive and specific when detecting the presence of bacteria in canine urine samples. Gram staining should be considered when bacteriuria is highly suspected and requires rapid identification while bacterial culture is pending.