Preliminary results on the validation of a novel method for measuring intra-abdominal pressure and gastric residual volume

Introduction

This study will look at the validation of a novel method combining measurement of gastric residual volume (GRV) and estimation of intra-abdominal pressure (IAP) via intragastric pressure (IGP).

Methods

In total 88 paired IAP and GRV measurements were performed in the HOB position in 23 mechanically ventilated ICU patients. The IAP was estimated by the height of the urine column via the bladder (that is, IBP) using the FoleyManometer (Holtech Medical, Charlottenlund, Denmark) and via the stomach (that is, IGP) with the new device (Gastro PV; Holtech Medical). The GRV was measured with the new device (GRVprototype) and via the classic method (GRVclassic). The male-to-female ratio was 2:1, age 62.3 ± 18.8 (range 22 to 86), BMI 25.3 ± 6.2 (16.6 to 40.4), APACHE II score 21.3 ± 4.1 (13 to 30), SAPS II score 50.7 ± 13.2 (17 to 83), and SOFA score 10.1 ± 2.8 (6 to 17). The number of measurements in each patient was four (except one patient with five, one patient with one and one patient with two measurements). Statistical analysis was done with SPSS-13 software, values are expressed as mean ± SD or median (and range).

Results

The mean IBP was 11.3 ± 4 and mean IGP was 11.7 ± 3.9. Correlation between the IBP and IGP was significant but moderate (R² = 0.37). Analysis according to Bland and Altman showed a bias and precision of 0.5 and 3 mmHg, respectively; however, the limits of agreement were large and ranged from -5.4 to 6.4 mmHg. The median GRVprototype was 100 ml (0 to 1,050) and median GRVclassic was also 100 ml (0 to 1,250). Correlation between the two methods was excellent (R² = 0.89). Analysis according to Bland and Altman showed a bias and precision of -1.3 and 59.2 ml, respectively, and the limits of agreement ranged from -117 to 114 mmHg. The median drainage time and return times were 3.1 minutes (0.5 to 15) and 2 minutes (0 to 21) for GRVprototype compared with 2 minutes (0.1 to 9) and 1 minute (0 to 8) for GRVclassic.

Conclusions

The preliminary results of an ongoing multicentre pilot study show that the gastro PV is a good alternative to the standard method for measuring GRV. Because the nurse can perform other tasks during drainage and return of the GRV, and the fact that the system remains closed during measurement, this could be a major step forward in standardisation of GRV measurement. Furthermore it allows screening for intra-abdominal hypertension via IGP estimation.