Intra-Abdominal Hypertension in Neonatal Intensive Care Patients

An increasingly common cause of Multiple Organ Dysfunction Syndrome (MODS) is mechanical injury/ischemia caused by elevated pressures within the abdominal cavity. This phenomenon has been termed intra-abdominal hypertension (IAH) with the final pathway of multiple organ dysfunction and failure termed abdominal compartment syndrome (ACS). In the neonate, IAH is known to accompany omphalocele, gastroschisis and diaphragmatic hernia repair. IAH has also been found to cause a need for neonatal extra corporeal membrane oxygenation (ECMO) and/or a subsequent failure of ECMO treatment.

While abdominal compartment syndrome is the final physiologic and clinically apparent expression of severe elevations of intra-abdominal pressure, earlier in the course of this process, significant organ dysfunction occurs at a sub-clinical level. If mild to moderately elevated abdominal pressure can be detected early, it may allow clinicians to intervene early and reverse the process, preventing progression to ACS and possibly reducing morbidity and mortality.

To date no study has investigated the correlation between bladder pressure (a surrogate measure of IAP) in neonates who may or may not have ACS. Thus, the ranges of normal and elevated IAP are not determined. There is suggestion from pediatric ICU patients that the threshold for IAH in children is less than that in adults. Likewise, the threshold for IAH in neonates may be expected to be even lower, but this remains to be determined.

In this study, IAP (via bladder pressure measurements) will be measured with a commercially available and FDA approved system which utilizes an electronic pressure transducer, tubing, and any bedside patient monitor with pressure measurement inputs. These types of monitors are standard in the NICU. The pressure transducer is attached to the bladder catheter via a two-way valve, allowing urine drainage in-between taking bladder pressure measurements. A small amount of sterile saline is infused into the bladder in order to make the IAP measurement. While there is an indwelling urinary catheter, bladder pressure measurements will be taken every 2-4 hours.

Inclusion criteria

• Any NICU patient is eligible for enrollment in this study if his/her medical condition has required the placement of a bladder catheter for urine drainage and who does not meet any of the following Exclusion Criteria.

Exclusion criteria

• Bladder trauma
• History of recent bladder surgery
• Neurogenic bladder