Assessing the bladder wall thickness using Point Of Care Ultrasound (POCUS), and its correlation with colony forming units in urine culture samples of critically ill patients with suspected Catheter Associated Urinary Tract Infection (CAUTI)

Indwelling catheters are used routinely in the Intensive Care Units (ICUs), usually for frequent and accurate monitoring of urinary output, which is indispensable for proper fluid balance in any critically ill patient. Approximately 15-25% of hospitalized patients, and 98% of ICU pts use a urinary catheter during their stay, and the majority of these patients are catheterized for 2-7 days. But one of the integral problem to urinary catheterization is urinary tract infection (UTI), which is the most common nosocomial infection worldwide and accounts for almost 30–40% of all healthcare associated infections. Eighty percent of UTIs are attributable to indwelling urinary catheter use. In severe cases, these infections may lead to bacteremia, urosepsis, and even mortality. In addition to pain and discomfort, CAUTIs cause prolongation of hospital stay by 1-4 extra days and increased use of antibiotics, with consequent development of resistant microbial strains. Now, diagnosing CAUTI in a critically ill patient is a Hercules task, as the patient, most of the times, is not capable of saying up the symptoms (like suprapubic tenderness), and the diagnostic modalities available to us takes time to diagnose CAUTI (Urine C/S, the accuracy of which also depends on how well the sample of urine has been taken out). As everyone knows, how time is crucial in diagnosing infection and sepsis, and each minute delay in initiating antimicrobial therapy increases mortality and morbidity by a great extent. Hence, timely and prompt diagnosis to CAUTI, though is challenging for any intensivist, but is the need of the hour. Now, we all have a portable USG machine in our ICU, accessible easily to us, which can be used bedside in real time. USG has been used extensively by urologists and radiologists, on OPD and mobile patients, to calculate post void retained urine volume, detrusor muscle thickness and bladder wall thickness in patients with overactive bladder and BPH, also in cystitis, bladder stones, congenital deformities of bladder and tumors. But bedside USG has never been used in critically ill patients for evaluation of bladder wall thickness in screening and diagnosing CAUTI in ICU. In ultrasonography of urinary bladder to measure BWT we use 3.5MHz curvilinear transducer. Transducer placed slightly above the symphysis pubis and BWT measurement obtained from the anterior bladder wall in both longitudinal and transverse planes. The bladder region will be first delineated precisely. From this delineated bladder region the bladder wall thickness will be calculated as the distance between the outer and inner surfaces of the bladder. Multiple measurements of the BWT for each participants will be taken and the average value for each participants will be used. With this background, we have proceeded with an aim to access serial ultrasonography in catheterized critically ill patients as a tool to correlate urinary bladder wall thickness (BWT) and urinary tract infection (CAUTI).