Table 3.
Results of the in vitro examination of measurement agreement of IVP and ACM-IGP technique compared to a water column in a container model
| Paired measurements | IAP mean (mmHg) | Spearman correlation coefficient (r2) | WSACS method validation criteria | MAPE (SD) (%) | |||||
|---|---|---|---|---|---|---|---|---|---|
| Experimental arrangement | Bias (mmHg) | Precision (mmHg) | LOA (mmHg) | PE (%) | |||||
| Target values according to [1]a | – | ≥ 0.6b | ≤ │1│ | ≤ 2 | − 4 to + 4 | ≤ 25 | c | ||
| Setting 1: gastric tube (5 Ch.) | ACM-IGP vs. water column | 86 | 8.4 | 0.99 | 0.1 | 0.2 | − 0.3 to 0.5 | 5 | 6 (13) |
| Gastric tube (5 Ch.) vs. water column | 86 | 8.0 | 0.99 | 0.8 | 0.3 | 0.2 to 1.4 | 8 | 17 (21) | |
| ACM-IGP vs. gastric tube (5 Ch.) | 86 | 8.0 | 0.99 | 0.7 | 0.4 | − 0.1 to 1.5 | 10 | 13 (14) | |
| Setting 2: gastric tube (8 Ch.) | ACM-IGP vs. water column | 86 | 8.3 | 0.99 | 0.3 | 0.2 | − 0.1 to 0.7 | 5 | 8 (16) |
| Gastric tube (8 Ch.) vs. water column | 86 | 8.4 | 0.99 | 0.1 | 0.4 | − 0.7 to 0.9 | 10 | 9 (18) | |
| ACM-IGP vs. gastric tube (8 Ch.) | 86 | 8.2 | 0.99 | − 0.2 | 0.4 | − 1.0 to 0.6 | 10 | 9 (20) | |
| Setting 3: transurethral catheter (6 Ch.) | ACM-IGP vs. water column | 86 | 8.5 | 0.99 | − 0.1 | 0.5 | − 1.1 to 1.1 | 12 | 9 (13) |
| Transurethral catheter (6 Ch.) vs. water column | 86 | 8.0 | 0.99 | 0.9 | 0.5 | − 0.1 to 1.9 | 13 | 16 (0) | |
| ACM-IGP vs. transurethral catheter (6 Ch.) | 86 | 8.0 | 0.99 | 0.9 | 0.5 | − 0.1 to 1.9 | 13 | 15 (12) | |
| Setting 4: transurethral catheter (8 Ch.) | ACM-IGP vs. water column | 86 | 8.7 | 0.99 | − 0.6 | 0.2 | − 1.0 to − 0.2 | 5 | 14 (22) |
| Transurethral catheter (8 Ch.) vs. water column | 86 | 7.9 | 0.99 | 1.1 | 0.6 | − 0.1 to 2.3 | 15 | 19 (20) | |
| ACM-IGP vs. transurethral catheter (8 Ch.) | 86 | 8.2 | 0.99 | 1.7 | 0.6 | 0.5 to 2.9 | 15 | 27 (16) | |
| Overall | ACM-IGP vs. water column | 344 | 8.5 | 0.99 | − 0.1 | 0.5 | − 1.1 to 0.9 | 12 | 9 (17) |
| IVP (transurethral catheter + gastric tube) vs. water column | 344 | 8.1 | 0.98 | 0.7 | 0.6 | − 0.5 to 1.9 | 15 | 15 (20) | |
| ACM-IGP vs. IVP (transurethral catheter + gastric tube) | 344 | 8.1 | 0.97 | 0.8 | 0.8 | − 0.8 to 2.4 | 20 | 16 (17) | |
ACM-IGP air-capsule-based measurement of intra-gastric pressure, Ch. Charriére, IAP intra-abdominal pressure, IVP intra-vesical pressure, LOA limits of agreement, MAPE mean absolute percentage error, No number, PE percentage error, SD standard deviation, WSACS Abdominal Compartment Society (formerly: World Society of Abdominal Compartment Syndrome)
aTarget value specifications according to WSACS method validation criteria (bias + precision + LOA + PE) for the interchangeability of two IAP measurement methods [1]
bSpearman’s correlation coefficient (r2; target: r2 ≥ 0.6)
cMean absolute percentage error (%; MAPE [19]) were calculated in addition to recommended WSACS criteria [1]