Should we perform decompressive laparotomy during severe acute pancreatitis with intra-abdominal hypertension below 25 mmHg: Only the gut knows

Abstract

We suggest that during severe acute pancreatitis (SAP) with intra-abdominal hypertension, practitioners should consider decompressive laparotomy, even with intra-abdominal pressure (IAP) below 25 mmHg. Indeed, in this setting, non-occlusive mesenteric ischemia (NOMI) may occur even with IAP below this cutoff and lead to transmural necrosis if abdominal perfusion pressure is not promptly restored. We report our experience of 18 critically ill patients with SAP having undergone decompressive laparotomy of which one third had NOMI while IAP was mostly below 25 mmHg.

Key Words: Acute pancreatitis, Abdominal compartment syndrome, Decompressive laparotomy, Mesenteric ischemia, Intra-abdominal pressure, Abdominal perfusion pressure

Core Tip: In a recent review, Nasa et al discussed the optimal timing for decompressive laparotomy during severe acute pancreatitis. In line with the authors, we think that practitioners should not only focus on intra-abdominal pressure (IAP) levels to consider laparotomy but should also consider the gut viability. Indeed, intra-abdominal hypertension may decrease bowel perfusion pressure and precipitate non-occlusive mesenteric ischemia even with IAP below 25 mmHg. The objective of decompressive laparotomy is to restore mesenteric blood flow and prevent from transmural necrosis from occurring.

TO THE EDITOR

We have read with great interest the review recently published by Nasa et al[1] in which they focused on decompressive laparotomy for abdominal compartment syndrome following severe acute pancreatitis (SAP). In this review, included studies reported patients with intra-abdominal pressure (IAP) > 25 mmHg at the time of laparotomy. The authors concluded that in the absence of strong evidence, surgical decompression may be considered in patients with increasing IAP and/or with progressive cardio-respiratory compromise when medical management fails. They also suggested that the development of irreversible visceral ischemia could explain the poor prognosis of these patients and that the optimal cutoff of IAP is not strongly established.

We agree with Nasa et al[1] that considering visceral ischemia is the cornerstone of the decision of performing decompressive laparotomy among these patients. Indeed, based upon our clinical experience, we suggest that decompressive laparotomy should be considered even among patients with IAP below 25 mmHg in whom non-occlusive mesenteric ischemia (NOMI) is highly suspected. We would like to report here our experience of laparotomy in patients with SAP and abdominal hypertension in which NOMI with irreversible bowel ischemia was found one third of the time.

Between January 2006 and March 2022, 18 patients (median age 60, 89% males) with SAP and intra-abdominal hypertension (IAH) (i.e., IAP > 12 mmHg) underwent exclusive decompressive laparotomy in our intensive care unit (ICU) (Table 1). Decision of surgery was guided by both worsening organ failures and IAH. However, IAP above 25 mmHg was not mandatory. At the time of surgery, median SOFA and IAP were 10 (9-12), and 20 (17-24) mmHg, respectively. For 6 out of 18 patients, initial macroscopic examination of the colon and small bowel during surgery showed acute mesenteric ischemia with transmural bowel necrosis. In all of them, mesenteric ischemia was non-occlusive. Lesions were localized in the colon for two patients and were diffused (colon and ileum/jejunum) for 4 patients (Table 1). Among these 6 patients, median IAP before surgery was 20 mmHg, and 5 out of 6 had IAP below 25 mmHg. Four out of six patients with transmural necrosis underwent resection. For 2 patients, the surgeon has considered that the resection was futile because of extensive transmural bowel necrosis. Four of the six patients with transmural necrosis died. Among the five patients with IAP below 25 mmHg, three died.

Table 1 Patients characteristics.

Characteristics	Population	Ischemia	No ischemia
	n = 18	n = 6	n = 12
Baseline characteristics
Age (yr)	60 [43; 67]	59 [54; 60]	60 [39; 70]
Male sex	16/18 (89%)	5/6 (83%)	11/12 (92%)
BMI (kg/m2)	31.7 [29.8; 35.7]	35.3 [32.2; 37.2]	30.6 [29.3; 32.1]
CTSI score	6 [4; 8]	7 [6; 9]	6 [4; 8]
SOFA score at ICU admission	7 [4; 11]	8 [6; 13]	7 [4; 10]
Severity at the time of laparotomy
IAP (mmHg)	20 [17; 24]	20 [18; 22]	21 [18; 25]
pH	7.26 [7.07; 7.30]	7.06 [6.93; 7.24]	7.27 [7.19; 7.32]
Lactate (mmol/L)	3.6 [2.9; 7.4]	10.4 [4.4; 15.0]	3.3 [2.8; 3.8]
SOFA	10 [9; 12]	14 [12; 17]	9 [8; 11]
PaO2/FIO2	174 [108; 227]	122 [108; 174]	206 [106; 258]
Norepinephrine dose (µg/kg/min)	0.71 [0.42; 0.88]	1.04 [0.50; 1.39]	0,63 [0.45; 0.72]
Non occlusive mesenteric ischemia
Transmural necrosis	6/18 (33%)	6	0
NOMI location
Localised-colon		2/6
Diffuse- Ileum/jejunum + colon		4/6
Surgical resection		4/6
Surgical abstention for futility		2/6
Outcome
28-d mortality	6/18 (33%)	4/6 (66%)	2/12 (17%)
1-yr mortality	10/18 (56%)	4/6 (66%)	6/12 (50%)
ICU length of stay (d)	24 [8; 45]	5 [2; 11]	44 [20; 67]
Hospital length of stay (d)	40 [10; 58]	6 [3; 29]	51 [30; 116]

Data are median [IQR] or n (%). BMI: Body mass index; CTSI: Computed tomography severity score; SOFA: Sequential organ failure assessment; IAP: Intra-abdominal pressure; NOMI: Non occlusive mesenteric ischemia; ICU: Intensive care unit.

In the setting of SAP, NOMI may be secondary to both circulatory shocks related to hypovolemia, and IAH. This results in decreased abdominal perfusion pressure (i.e., difference between mean arterial pressure and IAP) and decreased bowel perfusion pressure[2]. Indeed, the gut is particularly sensitive to ischemia, as mesenteric blood flow decreases as soon as IAP is above 10 mmHg[3].

A key point is that NOMI is a dynamic process. At the early phase, restoration of mesenteric blood flow may result in bowel recovery. In case of prolonged low abdominal perfusion pressure, transmural necrosis occurs, resulting in poor prognosis. A prolonged time with IAH, even if below 25 mmHg, may be deleterious.

In line with Nasa et al[1] and based on our experience, we suggest that during SAP with IAH, practitioners should consider decompressive laparotomy, even with IAP below 25 mmHg, when NOMI is clinically suspected. In this setting, NOMI may occur even with an IAP level lower than 25 mmHg, and waiting for such a cutoff before considering decompressive laparotomy may lead to delayed treatment and worse prognosis.