Comparison of Bladder Pressure Versus Regional Intestinal Tissue Oxygenation in Infants (BPvsNIRS)

The goal of this clinical trial is to learn more about intestinal regional oxygen saturation measurements made with near-infrared spectroscopy and bladder pressure measurements in infants without risk of intraabdominal hypertension. The main question it aims to answer is if - in comparison to bladder pressure - the regional intestinal oxygen saturation measured with near-infrared spectroscopy is stable in the muscle-relaxed, intubated patients and the awake and non-sedated patient. In case of participation the bladder pressure and the regional intestinal oxygen saturation (measured with near-infrared spectroscopy) will each be measured once intraoperatively and once postoperatively. Patients included in this study will be undergoing an operation which necessitates muscle-relaxation, as well as an indwelling urinary catheter during the operation and for a short-time thereafter for other reasons than this study.

Comparison of regional intestinal oxygen saturation (measured with near infrared-spectroscopy) and indirect intraabdominal pressure measurement (bladder pressure) in muscle-relaxed, sedated patients compared to awake, non-sedated patients.

Our primary endpoint is the regional intestinal oxygen saturation (rSpO2) measurement (average of 5 measurements taken every 30 seconds within 2 minutes) in muscle-relaxed, intubated patients

Our primary endpoint is the regional intestinal oxygen saturation (rSpO2) measurements (average of 5 measurements taken every 30 seconds within 2 minutes) in awake, non-sedated patients

Bladder pressure measurements measured under two different circumstances: once muscle-relaxed, intubated patients (i.e. under ideal circumstances for these measurements) and once in awake, non-sedated patients (less ideal circumstances).

taken once intraoperatively within the first 10 minutes after anaesthesia induction and once postoperatively within the first three postoperative days

Inclusion Criteria: Prepped and consented for laparoscopic pyeloplasty or minimal PSARP with perineal or vestibular fistula or lateral thoracotomy for the correction of esophageal atresia Age of 12 months old or less at operation Legal custodian gives consent Exclusion Criteria: Anterior abdominal wall thickness greater than 12 mm measured on preoperative MRI imaging if available Patients planned for additional intestinal surgeries or non-standard pyeloplasty, e.g. pyeloplasty with nephrostoma Patients planned for laparoscopic pyeloplasty whose intraoperative urine sample shows pathological results Patients with esophageal atresia who experience pulmonary decompensation and need urgent surgery for fistula clipping