Abstract 1098 Poster Session IV, Tuesday, 5/4 (poster 239)

Introduction: Gastric tonometry is a validated minimally invasive method for the estimation of gastric intramucosal pH (pHi). Data in the paediatric population are very limited. Concern about intestinal ischaemia in premature infants influences their clinical management and the timing of introduction of enteral feeds.

Aims: To evaluate the technique of gastric tonometry in a population of VLBW infants. To compare pHi with concurrent measurements of acid-base status, lactate and mesenteric doppler blood flow velocity.

Subjects: Fourteen infants <1500g (9M,5F) median birthweight 930g (range 527 - 1365), gestation 26.5 weeks (range 24.4 - 30.0) and CRIB score 6.0 (range 1 - 14).

Methods: A nasogastric tonometry catheter (size 5F) was inserted. pHi, lactate and doppler flow velocity were measured at 3,12,24 and 48 hours and then daily.

Results: Data (mean ± SD) for the first 48 hours are summarised below. (Table)

Table 1 No caption
Full size table

Intramucosal pH significantly correlated with arterial pH, r2=0.7, p=0.005. Within individual babies a widened gap between arterial and intramucosal pH was associated with clinically significant events. No significant correlations were found between pHi and time averaged peak velocity (TAPV) in the celiac (CA) and superior mesenteric (SMA) arteries or between pHi and lactate levels.

Conclusion: While this technique requires further validation prior to its use diagnostically, we speculate that pHi may be a better indicator of intestinal mucosal perfusion than doppler blood flow velocity measurements and may prove useful in identifying babies with disordered intestinal perfusion in whom early enteral feeding is contraindicated.