Continuous Intra-Gastral Monitoring of Intra-Abdominal Pressure in Critically ill Children – A Validation Study

DOI: https://doi.org/10.21203/rs.3.rs-124366/v1

Abstract

Background: In critically ill children, detection of intra-abdominal hypertension (IAH, >10mmHg) and abdominal compartment syndrome (ACS, =IAH + organ dysfunction) is paramount and usually monitored through intra-vesical pressures (IVP) as current standard. IVP however carries important disadvantages, being time-consuming, discontinuous, with infection risk through observer-dependent manipulation, and ill-defined for catheter sizes. Therefore, we sought to validate air-capsule-based measurement of intra-gastric pressure (ACM-IGP).

Methods: We prospectively compared ACM-IGP with IVP both in-vivo and in-vitro (water-column), according to Abdominal-Compartment-Society validation criteria. We controlled for patient age, admission diagnosis, gastric filling/propulsive medication, respiratory status, sedation levels and transurethral catheters, all influencing intra-abdominal pressure (IAP).

Results: In tertiary care PICU setting, finally, n=97 children were enrolled (median age, 1.3 years [range, 0 days -17 years], LOS-PICU 8.0 [1-332] days, PRISM-III-Score 13 [0-35]). In n=2.770 measurements pairs, median IAP was 6.7 [0.9 -23.0] mmHg. n=38 (39%) children suffered from IAH>10mmHg, n=4 from ACS. In-vitro against water-column, ACM-IGP correlated perfectly (r² 0.99, mean bias -0.1±0.5 mmHg, limits-of-agreement (LOA) -1.1/+0.9, percentage error [PE] 12%) as compared with IVP (r² 0.98, bias +0.7±0.6 mmHg, LOA -0.5/+1.9, PE 15%). With larger IVP catheters at higher pressure levels, IVP underestimated pressures against water-column. In-vivo, agreement between either technique was strong (r² 0.95, bias 0.3±0.8 mmHg, LOA -1.3/+1.9mmHg, PE 23%). No impact of predefined control variables on measurement agreement was observed.

Conclusions: In a large PICU population with high IAH prevalence, ACM-IGP agreed favourably with IVP. More wide-spread usage of ACM-IGP may improve detection rates of ACS in critically ill children.

Trial registration:

WHO-ICTRP-No. DRKS00006556 (German Clinical Trial Register). Registeres 12th September 2014, URL: https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00006556

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Tables

Table 1

Patient demographics

Parameter

Number (%) or

Median (range)

Enrolled patients

97 (100%)

Female

38 (39%)

Age (years)

1.3 (0.0 − 17.0)

Age category

•neonates

•infants

•toddlers

•school children

•adolescents

12 (12%)

29 (29%)

26 (27%)

16 (17%)

14 (14%)

BMI (kg/m²)

15.6 (8.9–33.0)

Length of stay at PICU (days)

8 (1–332)

Admission diagnoses

•cardiac and post-cardiac surgery

•paediatric surgical

•neurosurgical

•traumatological

•non-surgical (internal):

opulmonology

ooncologic

oinfectious (sepsis)

46 (47%)

26 (27%)

9 (9%)

8 (8%)

3 (3%)

3 (3%)

2 (2%)

PRISM-III-score (first day of enrolment)

13.0 (0.0–35.0)

Prevalence of IAH overall

•IAH grade I (10–12 mmHg)

•IAH grade II (13–15 mmHg)

•IAH grade III (≥ 16 mmHg)

38 (39%)

27 (28%)

9 (9%)

2 (2%)

Prevalence of ACS

4 (4%)

Mortality

8 (8%)

Abbreviations: BMI – body mass index; PICU – Pediatric Intensive Care Unit; PRISM-III-score – paediatric risk of mortality score III [12]; IAH – intra-abdominal hypertension; ACS: Abdominal Compartment Syndrome
 
Table 2

Results of primary and secondary analyses for in-vivo measurement agreement of IVP and ACM-IGP methods in 97 paediatric patients
 

Paired measurements per patient

[median (range)]

IAP

[median (range)]

Spearman correlation coefficient

(r2)

WSACS method validation criteria

MAPE

(SD)

[%]

ACM-IGP

[mmHg]

IVP

[mmHg]

No of patients/ measure pairs

Bias

[mmHg]

Precision

[mmHg]

LOA

[mmHg]

PE

[%]

Target values*

-

-

-

≥ 0.6**

> 20 subjects

≤│1│

≤ 2

-4 to + 4

≤ 25

***

Primary analysis

1

6.8

(1.8–20.3)

6.0

(2.0–19.0)

0.95

97 / 97

0.3

0.8

-1.3 to + 1.9

23

10 (11)

Secondary analysis

21

(1–132)

6.8

(0.9–23.0)

6.0

(1.0–20.0)

0.82

97 / 2770

0.3

1.2

-2.1 to + 2.7

34

14 (16)

Abbrev.: 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)
 
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 Measure-ments

IAP

mean [mmHg]

Spearman Correlation coefficient (r2)

WSACS method validattion criteria

MAPE

(SD)

[%]

Experimental arrangement:

  

Bias [mmHg]

Precision [mmHg]

LOA

[mmHg]

PE

[%]

Target values according to [1]*

-

  

≥ 0.6**

≤│1│

≤ 2

-4 to + 4

≤ 25

***

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)

Abbrev.: 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)