Application of electrical impedance tomography-guided PEEP titration in acute respiratory distress syndrome patients with intra-abdominal hypertension

doi:10.5847/wjem.j.1920-8642.2026.024

Abstract

Abstract:

BACKGROUND Individualized positive end-expiratory pressure (PEEP) titration is a crucial technique in mechanical ventilation therapy for acute respiratory distress syndrome (ARDS) patients with intra-abdominal hypertension (IAH). This study aimed to evaluate the effectiveness of electrical impedance tomography (EIT)-guided PEEP titration in this population.

METHODS: This prospective study enrolled 36 ARDS patients, including 22 patients with IAH and 14 without IAH. All the patients underwent EIT-guided PEEP titration at the intersection point between alveolar overdistension and collapse during a decremental PEEP trial. The changes in pulmonary ventilation distribution, respiratory mechanics and hemodynamics during the titration process were observed.

RESULTS: After EIT-guided PEEP titration was performed, the PEEP, peak inspiratory pressure and plateau pressure increased significantly (P<0.05). Furthermore, no significant differences were observed in respiratory system compliance, tidal volume, driving pressure, or the 4*DP+RR index between the two groups (P>0.05). The mechanical power increased in the non-IAH (NIAH) group after PEEP titration (P<0.05). Ventilation in gravity-dependent lung regions significantly increased (P<0.05), and the oxygenation index (PaO₂/FiO₂) improved significantly (P<0.05) in both groups. However, blood pressure, heart rate, respiratory rate, central venous pressure, and lactate levels did not significantly change. In the IAH group, the PaO₂/FiO₂ ratio improved less than that in the NIAH group did (P<0.05).

CONCLUSION: In our study, individualized PEEP titration guided by EIT improved oxygenation in ARDS patients with concomitant IAH without significantly affecting hemodynamics. The presence of IAH may limit the improvement of oxygenation during EIT-guided PEEP titration.

Key words: Acute respiratory distress syndrome, Positive end-expiratory pressure, Electrical impedance tomography, Intra-abdominal pressure

Hui Wen, Maiying Fan, Junliang Xiao, Zhiqun Liu, Xiaohua Liu, Shuzhen Mao, Xiaotong Han, Fengling Ning. Application of electrical impedance tomography-guided PEEP titration in acute respiratory distress syndrome patients with intra-abdominal hypertension[J]. World Journal of Emergency Medicine, 2026, 17(1): 70-75.

Figures/Tables 3

Figure 1.

Table 1.

Characteristics of the ARDS patients with and without IAH

Variables	Total (n=36)	IAH (n=22)	NIAH (n=14)	P-value
Demographics
Male sex, n (%)	25 (69.44)	15 (68.18)	10 (71.43)	0.837
Height, cm, mean±SD	167.08±7.77	167.82±8.63	165.93±6.33	0.485
Weight, kg, mean±SD	71.31±13.23	75.27±13.29	65.07±10.84	0.022*
Body mass index, kg/m², mean±SD	25.33±3.40	26.48±3.06	23.52±3.21	0.009**
APACHE II score, mean±SD	19.67±5.79	21.05±4.96	17.50±6.49	0.073
SOFA score, median (IQR)	8 (4, 23)	8.5 (7, 10)	7.0 (6.0, 8.3)	0.023*
IAP, mmHg, mean±SD	13.19±2.93	14.88±2.41	10.53±1.14	<0.01**
PiO₂/FiO₂, mmHg, mean±SD	161.15±61.38	151.69±65.16	176.01±53.81	0.252
Central venous pressure, median (IQR)	-	12.0 (10.8, 14.0)	10.0 (7.8, 11.0)	0.009**
ARDS origin, n (%)
Pulmonary	16 (44.44)	7 (31.82)	9 (64.29)	0.056
ARDS severity, n (%)
Mild	8 (22.22)	5 (22.73)	3 (21.43)	0.292
Moderate	21 (58.33)	11 (50.00)	10 (71.43)
Severe	7 (19.44)	6 (27.27)	1 (7.14)
Diagnosis, n (%)
Pyemia	20 (55.56)	14 (63.64)	6 (42.86)	0.221
Severe pneumonia	19 (52.78)	9 (40.91)	10 (71.43)	0.074
Severe acute pancreatitis	10 (27.78)	10 (45.45)	0 (0.00)	0.003**
Trauma	2 (5.56)	1 (4.55)	1 (7.14)	0.740
Other	2 (5.56)	1 (4.55)	1 (7.14)	0.740
Comorbidity, n (%)
Hypertension	16 (44.44)	10 (45.45)	6 (42.86)	0.878
Coronary disease	9 (25.00)	5 (22.73)	4 (28.57)	0.693
Diabetes mellitus	11 (30.56)	5 (22.73)	6 (42.86)	0.201
Chronic obstructive pulmonary disease	5 (13.89)	2 (9.09)	3 (21.43)	0.297
Hepatic insufficiency	7 (19.44)	7 (31.82)	0 (0.00)	0.019*
Renal insufficiency	10 (27.78)	9 (40.91)	1 (7.14)	0.027*
History of tumors	4 (11.11)	1 (4.55)	3 (21.43)	0.116
Recent surgical history	7 (19.44)	5 (22.73)	2 (14.29)	0.533
Treatment, n (%)
Glucocorticoid	8 (22.22)	5 (22.73)	3 (21.43)	0.927
Vasoactive drug	19 (52.78)	15 (68.18)	4 (28.57)	0.020*
Muscle relaxants	2 (5.56)	2 (9.09)	0 (0.00)	0.246
Outcome
28-day mortality, n (%)	12 (33.3)	10 (45.45)	2 (14.29)	0.053
Mechanical ventilation time, d, median (IQR)	10 (7, 16.75)	10 (7.8,17.3)	9 (6.8, 16.3)	0.591
ICU hospitalization, d, median (IQR)	14.5 (8, 21.5)	13.5 (8, 20.5)	15 (10.3, 26)	0.416
Hospitalization, d, median (IQR)	19 (13.25, 31.75)	18.5 (9.5, 34.5)	19.5 (14.8, 27.3)	0.770

Table 1.

Table 2.

Comparison of respiratory mechanics, gas exchange, and hemodynamic changes in two groups before and after titration

Variables	IAH group pairs		P-value	NIAH group pairs		P-value	Change value before and after PEEP titration		P-value
Variables	After PEEP titration	Before PEEP titration	P-value	After PEEP titration	Before PEEP titration	P-value	IAH group	NIAH group	P-value
Respiratory mechanics parameters
PEEP, cmH₂O	12.5 (10.0, 15.0)	10.0 (6.0, 10.5)	<0.01**	12.0 (8.8, 14.0)	7.0 (5.0, 8.5)	<0.01**	3.45±3.10	4.14±2.11	0.471
Tidal volume, mL	447.59±88.76	433.09±62.36	0.354	419.93±68.35	417.79±58.03	0.851	14.50±71.80	2.14±41.98	0.564
PIP, cmH₂O	29.0 (24.0, 33.3)	26.5 (19.0, 32.8)	0.015*	28.5 (24.0, 34.5)	24.0 (19.8, 29.3)	0.047*	2.55±4.52	3.86±6.37	0.475
Pplat, cmH₂O	22.67 (20.9, 26.7)	20.5 (18.0, 22.9)	0.002**	21.15 (18.3, 27.0)	18.04 (16.5, 20.0)	0.008**	2.95±3.86	3.24±3.85	0.827
DP, cmH₂O	10.86±2.30	11.07±2.68	0.652	10.93±1.99	12.02±2.48	0.131	-0.21±2.15	-1.08±2.52	0.273
RR, breaths/min	19.55±3.78	21.36±3.82	0.047*	20.00±4.71	19.93±5.06	0.947	-1.82±4.03	0.07±3.91	0.175
Cstat, mL/cmH₂O	39.5 (34.8, 47.0)	37.5 (31.5, 51.3)	0.653	37.0 (34.5, 43.5)	38.5 (30.5, 42.3)	0.385	0.17±10.37	1.86±7.73	0.606
MP, J/min	18.93 (14.3, 23.9)	20.71 (13.2, 24.7)	0.394	17.78 (13.8, 23.4)	14.49 (11.4, 17.8)	0.024*	-1.14±6.15	-3.82±5.60	0.197
4DP+RR	62.99±9.60	65.64±10.40	0.168	63.72±9.35	67.99±12.10	0.114	-2.66±8.72	-4.27±9.42	0.604
Gas exchange parameters
P/F	183.54±75.11	126.58±29.19	0.008**	254.37±106.75	115.74±26.70	0.001**	56.96±91.80	138.62±121.79	0.028*
SpO₂, %	96.07±3.63	96.09±3.15	0.986	97.29±2.73	94.86±6.98	0.226	1 (0.0, 2.3)	0 (-1.3, 1.3)	0.074
pH	7.36±0.07	7.38±0.10	0.335	7.43±0.07	7.40±0.08	0.051	-0.01±0.06	0.03±0.04	0.052
PaO₂, mmHg	92.00±22.34	80.05±20.18	0.019*	108.93±36.71	88.36±26.12	0.044*	11.95±21.96	20.57±34.60	0.366
PaCO₂, mmHg	43.14±9.53	41.82±11.49	0.397	40.93±9.67	43.43±8.93	0.094	1.32±7.15	-2.50±5.17	0.093
Regional pulmonary ventilation (%)
ROI1	14.82±5.04	17.32±5.16	<0.01**	11.36±3.30	15.93±4.38	0.002**	-2.50±2.84	-4.57±4.47	0.097
ROI2	49.82±8.05	53.95±9.22	0.034*	45.50±10.65	53.00±7.98	0.003**	-4.14±7.84	-7.50±7.77	0.217
ROI3	29.27±9.62	24.00±9.85	0.006**	32.93±10.10	23.86±9.97	0.001**	5.27±8.15	9.07±7.52	0.170
ROI4	6.09±3.62	4.68±2.61	0.003**	10.29±6.33	7.64±3.25	0.029*	1.41±1.74	2.64±4.03	0.295
δEEVI	-	-	-	-	-	-	0.66±0.37	0.43±0.47	1.488
Circulating hemodynamic parameters
MAP, cmH₂O	86.48±15.30	84.65±13.19	0.305	85.50±11.56	86.19±11.01	0.827	1.83±10.22	-0.69±11.62	0.498
HR, beats/min	103.00±19.54	100.41±19.05	0.397	95.57±25.93	93.79±23.50	0.593	2.59±14.04	1.79±12.18	0.861
CVP, cmH₂O	12.5 (10.0, 14.0)	12.0 (10.8, 14.0)	0.412	9.5 (8.0, 12.0)	10.0 (7.8, 11.0)	0.775	0.5 (-1.5, 2.0)	0 (-1.0, 2.0)	0.882
Lactate, mmol/L	1.3 (1.0, 2.0)	1.3 (0.9, 2.4)	0.204	1.2 (0.9, 1.9)	1.2 (0.9, 1.6)	0.626	-0.15 (-0.3, 0.5)	-0.1 (-0.5, 0.2)	0.580

Table 2.

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