Feasibility and Safety of an Ileus Management Protocol for Postoperative Ileus
Phase: NA
Conditions: Ileus Postoperative, Nasogastric Tube
Sponsor: University of Lausanne Hospitals

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 Feasibility and safety of an Ileus Management Protocol for postoperative ileus  
NCT ID not yet assigned  
Date: July, 15 th 2025 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Feasibility and safety of an Ileus Management Protocol for postoperative ileus 
Maria Teresa Torres˚1, Dimitri Chappalley˚1, Gabriel Heierli1, Nicolas Dupasquier1, 
David Fuks1, Dieter Hahnloser1, Martin Hübner1, Fabian Grass1 
1Department of Visceral Surgery, University Hospital Lausanne (CHUV), University of Lausanne 
(UNIL), Lausanne, Switzerland 
˚shared first authorship 
 
Correspondence to: 
Fabian Grass 
Department of Visceral Surgery 
University Hospital CHUV 
Rue du Bugnon 46 
1011 Lausanne , Switzerland 
Phone:  
+41 21 314 24 00 
Fax:  
+41 21 314 24 11 
E-mail : 
fabian.grass@chuv.ch 
 
Short title:  
 
Algorithm for postoperative ileus 
 
 
 
 
 
 
 
 
 
 
 
 
 
Abbreviation: 
 
POI –  postoperative ileus, NGT – nasogastric tube, ERP – 
Enhanced recovery pathway, I-MAP: Ileus MAnagement Protocol, LOS: Length of 
stay, WSC: Water soluble contrast 
 
No conflict of interest or funding source to declare. 
 

3 
 
Abstract 
Background 
Postoperative ileus (POI) remains one of the most frequent complications after 
gastrointestinal surgery with only limited options for prevention and treatment. 
Management of POI shows wide variation due to limited evidence. The aim was to 
establish a standardized treatment algorithm for POI and to study its feasibility and 
safety. 
Methods 
The core team developed a comprehensive and pragmatic treatment algorithm to 
standardize management of POI (POI algorithm). This pathway was then studied in a 
single-center prospective cohort study including consecutive patients developing POI 
and requiring nasogastric tube (NGT) insertion after abdominal surgery. Primary 
outcome measure was compliance with the pathway.  
Results 
In 9 months, 60 patients with POI were screened for eligibility and 47 were included 
in the trial. 40 patients were treated according to the protocol (compliance 85%) and 
39/40 (98%) were successfully treated conservatively. Median NGT time was 2 (IQR 
2-3) days, and 3 patients required NGT reinsertion (10%) after prior removal. Median 
hospital stay was 12 (IQR 8-16) days and 13.1 (IQR 5.5-15) days after surgery and 
insertion of NGT, respectively. One bronchoaspiration was documented in this 
prospective cohort.  
Conclusions 
The suggested POI algorithm proved to be feasible and safe. Its superiority 
compared with best physician’s choice needs to be confirmed through a multicenter 
randomized trial.  

4 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
This study has been registered by the Research Ethics Commission on human 
beings of the Canton de Vaud (CER-VD) (2022-01420) 
Key words: postoperative ileus, gastrointestinal surgery, hospital stay, treatment 
algorithm  
 

5 
 
Introduction 
Postoperative ileus (POI) affects between 10-20 % of patients after gastrointestinal 
surgery and is associated with an overall increase in morbidity, hospital stay and costs 
(1,2). Multiple definitions exist and only recently, some consensus has been reached 
to come to a common language (3–5). So far, preventive measures have not 
convincely reduced POI and even enhanced recovery pathways (ERP) could not 
reduce the incidence but only advance resolution of POI (6). The treatment of POI 
underlies wide variation and the evidence for the management of the nasogastric tube 
(NGT) is very limited with regards to indication for insertion, duration, safe removal, 
and clamping trials (7,8). Therefore, treatment of POI is delivered in most hospitals 
case-by-case upon discretion of the treating physician. This lack of standardization for 
management of one of the most frequent complications in gastrointestinal surgery is 
concerning, especially given that standardization in itself has been shown to improve 
outcomes even in fields with limited evidence (9,10). 
The aim of this feasibility study was therefore to elaborate a standardized treatment 
algorithm for POI and to test its feasibility and safety in a prospective cohort of patients. 

6 
 
Materials and Methods  
Study Design 
This is a single-center prospective cohort study aiming to assess feasibility and 
safety of a standardized treatment algorithm for POI (I-MAP: Figure 1). The study 
was approved by the Research Ethics Commission on human beings of the Canton 
de Vaud (CER-VD) (2023-00759). The study adhered to the ethical principles of the 
Declaration of Helsinki and the principles and procedures for integrity in scientific 
research involving human beings (STROBE statement, Table S1). All participants 
provided general consent (11). 
Participants  
Eligible were consecutive adult patients who underwent abdominal surgery and 
developed post-operative ileus within 30 days. Exclusion criteria were preoperative 
bowel obstruction, anastomotic leak, prophylactic nasogastric tube (NGT) placement, 
pregnancy, and lack of general consent. 
Intervention 
The treatment algorithm was elaborated by the study group based on the available 
evidence, clinical judgement and practical considerations [Figure 1]. The 
implementation of the algorithm was carried out in collaboration with a 
multidisciplinary team of experts within our institution composed of surgeons, clinical 
nurses and nurse practitioners, and pharmacists. It was first presented during an 
educational symposium to the entire divisional medical staff in March 2023, and 
subsequently to nursing heads and staff during dedicated sessions in May 2023. 
Adaptations were then discussed among stakeholders until final agreement. Pocket 
cards summarizing the algorithm were printed and distributed to each caregiver 
(residents and nurses) in the visceral surgery department. 

7 
 
Postoperative ileus (POI) was defined as insertion of a nasogastric tube (NGT) at any 
time after surgery due to symptoms such as persistent nausea, vomiting, abdominal 
distension, or inability to tolerate oral intake. This objective definition was chosen as 
a hard endpoint to reflect clinical practice and to reduce interobserver variability 
(3,12). Resolution of POI was defined as tolerance of the institutional refeeding policy 
(light diet within 24 hours after NGT removal, normal diet thereafter). 
Management decisions were mainly based on NGT output over the last 12 hours 
assessed at 8 a.m., coinciding with shift changes of the nursing team. Depending on 
NGT output, Water Solution Contrast (WSC) was applied through the NGT as 
therapeutic and diagnostic management tool with re-assessment of patients 4 hours 
after administration (NGT clamp test). If WSC was not tolerated, a CT-scan or x-Ray 
was performed. The decision to perform a CT scan or x-Ray was made by the 
operating surgeon based on clinical presentation and lab results. A CT scan was the 
preferred modality when small bowel obstruction was suspected. Neostigmine® as a 
prokinetic medication was administered only after small bowel obstruction was ruled 
out (13,14). The WSC used at our institution was TELEBRIX® gastro sol (Guerbet 
AG, Zürich, CH), containing ioxitalamic acid 300 mg/ml. ROBINUL Neostigmine® sol 
inj (Sintetica SA, Ticino, CH) containing Neostigmine metilsulfate (2.5 mg) diluted in 
500 mL NaCl 0.9% was injected over 5 hours. It was administered on the ward 
without need for cardiac monitoring in patients without relative contraindications 
(including bronchospasm, bradycardia, hypertension, congestive heart failure, 
thyrotoxicosis, epilepsy, warranting cardiac monitoring in the intermediate care unit) 
after careful patient, followed by clinical monitoring at one-hour intervals. 
 
 

8 
 
Outcomes/study endpoints 
The primary endpoint for the present study was the feasibility of the I-MAP algorithm, 
measured by the ratio of patients treated according to the algorithm to the total 
number of eligible POI patients during the study period. A protocol adherence rate of 
85% was defined as minimal threshold to demonstrate feasibility (15). Feasibility of 
the I-MAP protocol was assessed on a patient level and defined as adherence to all 
key steps of the algorithm. Deviations were systematically recorded and categorized 
as either major (omission of WSC, failure to clamp NGT, premature administration of 
neostigmine) or minor (delays not affecting treatment flow, variations based on 
patient fragility or surgeon discretion). Only patients with major deviations were 
considered non-adherent. Minor deviations were tolerated if the overall treatment 
sequence remained consistent within the protocol’s intent. The rate of adherence was 
calculated as the proportion of patients who followed the algorithm without major 
deviation. In addition, the most frequently deviated algorithm components were 
recorded to identify areas requiring refinement. 
Secondary outcomes included NGT reinsertion, total time with NGT, length of stay 
(LOS), conservative treatment failure, and complications such as pneumonia, 
bronchoaspiration and other adverse events related to POI. 
Data synthesis and analysis 
Categorical variables were expressed as frequencies and percentages, and 
continuous variables as median (range) and mean (±SD). Data analysis was 
performed using Microsoft Excel 365, (Microsoft Corporation, Redmond, WA, USA 
Software Group, Chicago, IL, USA).  

9 
 
Results 
Patients 
Between June 15, 2023 and March 1, 2024, 60 patients with POI were screened for 
eligibility and 47 were included in the trial [Figure 2]. Out of the initially 60 screened 
patients, six refused study consent, five met an exclusion criterion as they were 
monitored in the intensive care unit, one had a maintained NGT at the end of surgery 
and one presented with a state of delirium impeding study participation. The 
remaining 47 patients constituted the final study cohort. 
Patient characteristics and surgical details of the study cohort are summarized in 
Table 1. POI occurred a median of 3 (IQR 2-3) days after surgery. 
Primary outcome 
In total, 40 out of 47 were treated per protocol (compliance rate 85%) and 39/40 
(98%) were successfully treated conservatively [Figure 2]. One patient required re-
operated for adhesive small bowel obstruction.  
Reasons for protocol deviation were: administration of WSC was intentionally 
delayed by the senior surgeon (n=3); neostigmine was voluntarily initiated as a first 
place treatment by the senior surgeon (n=2); NGT was not clamped before removal 
despite 300-1000 ml of drainage (n=1) related to a medical error; delay of several 
days before WSC administration for safety reasons in a fragile patient upon clinical 
judgment by a senior surgeon (n=1). 
Secondary outcomes  
NGTs were inserted on at a median of postoperative day (POD) 3 (range 1-17), with 
drainage of a median of 640 ml (range 0-2200ml) of gastric content after insertion. 
The median time of NGT drainage was 2 days (range 0-12).  

10 
 
Three patients required NGT reinsertion on days 0, 3, and 16 after initial removal. 
The first patient on day 0 because of an evisceration, the second on day 3 due to 
adhesive small bowel obstruction, the third on day 16 due to bilioma leading to 
recurrent paralytic ileus. None of them required reoperation, while one experienced 
bronchoaspiration before NGT reinsertion, and one developed pneumonia without 
signs of bronchoaspiration 4 days after NGT reinsertion. Three patients received 
neostigmine, allowing NGT removal the day after administration, with no drug-related 
side effects. Two patients needed surgery during POI treatment, one for evisceration 
(POD 6) and one for small bowel obstruction due to an epiploic adherence 
(misdiagnosed POI, POD 7).  
The median length of stay in the hospital from the index operation was 12 days (IQR 
8-16), however, this included the waiting time until transfer to a rehabilitation facility. 
The median length of stay from the onset of POI until discharge was 9 days (IQR 5-
12).  
Out of the 47 patients included in the study, the protocol was not followed in 7 
patients (15%). Among them, 3 were in the ICU, where it was challenging to apply 
the protocol for logistic reasons. In 2 cases, neostigmine was immediately 
administered according to requests of the senior surgeon to bypass the protocol. The 
remaining 2 patients were transferred to the ward with a postoperative NGT in place. 
 

11 
 
Discussion 
This pragmatic POI pathway proved to be feasible and safe in our institutional 
practice and can be used in clinical practice to standardize patient care. Clinical 
superiority, compared to case-by-case decisions, needs to be confirmed through 
multicenter RCTs. 
Standardized care pathways help to simplify clinical decision making, timely launch 
therapeutic strategies and, ultimately, to improve and expedite patient care (16). 
Postoperative ileus is one of the most common complications after abdominal 
surgery and lacks standardized management. Our institutional algorithm is an 
attempt to facilitate decision-making for medical and nursing staff. This is of particular 
importance in academic hospitals with regular turnover of junior staff. The proposed 
algorithm was based on a comprehensive review of current literature and guidelines, 
also considering institutional experience and logistic feasibility in our center (17). A 
recent meta-analysis revealed limited evidence concerning pharmacological 
prevention and therapy of POI, while emphasizing the importance of opioid sparing 
concepts, reduction of sympathetic hyperactivity and laxatives into multimodal 
perioperative approaches (18). Longstanding ERP experience with focus on 
preventive measures including early mobilization, stringent fluid management and 
early resumption of an oral diet to mitigate the inflammatory stress response and 
promote bowel recovery are integral part of perioperative care in our center (19–21). 
Pharmacological attempts to treat POI within ERPs include alvimopan, neostigmine, 
lidocaine and  other prokinetics(22). Alvimopan has demonstrated its efficacy in 
enhancing gastrointestinal recovery following bowel resection surgeries and is 
approved for use in the United States (23). However, despite its clinical benefits, it 
remains unavailable in the European Union due to regulatory and market constraints. 

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Conversely, Neostigmine has shown promising results in small-scale studies, but 
broader validation is lacking. While WSCA appears to be beneficial in enhanced care 
pathways, it is unlikely to provide a direct therapeutic benefit and should rather be 
considered a supportive element in postoperative protocols than an active 
pharmacological agent (24). 
 Definitions of POI remain inconsistent across studies, despite efforts to standardize 
(7). A systematic review of randomized controlled trials revealed close to 800 
different outcomes and 73 measures related to POI with a wide heterogeneity of 
definitions (25). While POI relates to “prolonged POI” in most studies, it should be 
distinguished from the “obligatory POI” referring to the physiological ileus that follows 
all GI surgeries to a certain extent. A nested methodological study protocol to assess 
gastrointestinal recovery in cases of POI and small bowel obstruction was initiated in 
2019 (26). A core outcome set with focus on patient reported outcomes (PROMs) 
was established recently through a consensus meeting (27). The aim was to provide 
a universal framework to evaluate the effectiveness of clinical interventions to reduce 
POI, ultimately helping to facilitate informed decision-making. 
Our protocol focused on an easily reproducible and pragmatic decision framework, 
mainly focusing on drainage volumes to initiate further actions. Water-soluble 
contrast (WSC, gastrografin) was integral part of the algorithm and timely launched, 
mainly for its therapeutic purpose through a hyperosmolar effect to counteract gut 
wall edema (28). As a distinctive feature, our protocol suggested repeated WSC 
administration every morning at fixed hours depending on drainage thresholds until 
POI resolution, with imaging studies 4 to 8 hours after administration, mainly to 
exclude an obstructive ileus component. Neostigmine as a parasympathomimetic 
drug enhancing smooth muscle tone was used as a second line treatment due to the 

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beneficial effect on bowel recovery revealed in a recent systematic review (28). This 
medication needs to be embedded in an opioid-sparing analgesia strategy for the 
best possible results. Patients were advised to report abdominal cramps during the 5-
hour administration, and particular caution was warranted in patients with preexisting 
pneumopathy, given the low risk of pulmonary bronchospasm, edema and respiratory 
failure (30). An x-Ray after WSC administration (to confirm WSC advancement to the 
colon) or CT-scan at the surgeon’s discretion was mandatory before neostigmine 
administration to rule out a mechanical obstructive component needing surgical 
management. The limited use of this drug in our study—administered to only three 
patients—along with the need for precautions such as avoiding use in elderly patients 
and monitoring those with cardiopulmonary conditions, reflects a cautious approach. 
This hesitance suggests that a more systematic application may require further 
protocol refinement.  
Our proposed algorithm incorporated simple measures launched according to 
predefined NGT drainage cut-offs assessed at periodic intervals, allowing for periodic 
decision-making involving the entire care team. Feasibility of our algorithm was 
confirmed through high adherence to the protocol (85%), facilitated by involvement of 
all caregivers. Taken together, the algorithm has proven its utility for our clinical 
practice. 
The algorithms’ safety has also been demonstrated, considering pulmonary 
complications and bronchoaspiration, frequent POI-related events, occurred rarely in 
the present cohort (31). Surgery required in two patients for evisceration and small 
bowel obstruction was potentially related to or misdiagnosed as POI.  
Future research should focus on validating this algorithm in larger, multi-center 
studies to further establish its efficacy and generalizability. Additionally, ongoing 

14 
 
education and engagement of healthcare providers and patients will be crucial in 
maintaining high compliance rates and optimizing postoperative outcomes. 
Several limitations of the present study need to be addressed. The study was 
powered to assess feasibility without a control group. A former institutional series 
focusing on POI occurrence however demonstrated a lack of standardization, a 
slightly longer LOS and WSC use in only 35% of cases (32). The LOS in the present 
study may also be overestimated due to logistic drawbacks (delayed transfer to 
rehabilitation facilities). Hence, conclusions regarding clinical efficacy are not 
possible at this stage. The underlying treatment algorithm was based on limited 
available evidence also including logistic considerations and subjective clinical 
judgment of the core team. Lengths of stay were long, also due to important delays 
related to patients awaiting transfer to rehabilitation facilities. Detailed functional 
recovery parameters including resumption of an oral diet were not assessed in the 
setting of this study. These metrics are presently assessed in the setting of an 
institutional prospective observational protocol (project Recovery (CER-VD 2024-
00706)). Finally, despite appearing safe and feasible in our practice, the next step to 
assess the protocol consists of an in-depth comparative evaluation. 
In conclusion, the proposed standardized treatment algorithm for POI can be safely 
used in clinical routine and may, due to its simplicity, also work in other hospitals and 
settings. Further assessment of clinical impact and potential refinements will require 
prospective multi-center evaluation with specific focus on time to ileus resolution, 
NGT reinsertion, total length of hospital stay, and patient satisfaction. 
 

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Acknowledgments 
The authors kindly thank Sandrine Geinoz, Magali Gaiani, and Allain Emilie for their 
valuable help in data acquisition. 
 
Statement of Authorship 
Study conception and design: DC, DH, FG, MH 
Acquisition of data: DC, GH, ND, MTT 
Analysis and interpretation of data: DC, GH, MH, FG 
Drafting of manuscript: MTT, DC, FG 
Critical revision of manuscript: all authors 
Maria Teresa Torres and Chappalley Dimitri share first authorship 
 
All authors have no conflict of interest to declare. 

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TABLE 1 Baseline characteristics 
Item  
Number of patients, n 
47 
Age (years), median (range) 
67 
(28-92) 
Gender (female), n (%) 
20 
(42) 
Comorbidities 
N=47 
Diabetes, n (%) 
2 
(4) 
Active smoker, n (%) 
11 
(23) 
Alcohol abuse, n (%) 
2 
(4) 
ASA classification (<3), n (%) 
23 
(49) 
Cardiopathy, n (%) 
10 
(21) 
COPD, n (%) 
1 
(2) 
Cirrhosis, n (%) 
2 
(4) 
BMI (kg/m2), median (range) 
24.4 (15.7-37.2) 
Surgical specifics 
N=47 % 
Cancer Surgery, n (%) 
21 
(45) 
Emergency Surgery, n (%) 
15 
(30) 
Surgical duration (min), median (range) 
168 
192.5 (59 – 
600) 
Laparotomy, n (%) 
32 
(68) 
MIS, n (%) 
15 
(32) 
Contamination class 
Clean or clean-contamined, n (%) 
36 
(77) 
Contamined, n (%) 
11 
(23) 
Type of colorectal surgery 
N=47  
Left colectomy 
10 
(21) 
Right colectomy 
10 
(21) 
Rectal resection 
6 
(14) 
Small bowel resection  
8 
(18) 

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Appendectomy 
3 
(6) 
Other colorectal 
3 
(6) 
Other type of surgery 
N=47  
- Debulking without colorectal resection 
3 
(6) 
- HPB 
1 
(2) 
- Hernia surgery 
2 
(4) 
- Nephrectomy 
1 
(2) 
 
Table 1: ASA – American Society of Anaesthesiologist score, COPD – chronic obstructive pulmonary 
disease, BMI – body mass index, MIS – minimally invasive surgery, HPB – hepatobiliary and 
pancreatic surgery 
 
 
 

21 
 
Figure 1 
I-MAP protocol 
 
I-MAP – Ileus management protocol, POI – postoperative ileus, NGT – nasogastric tube, WSC – 
water-soluble contrast, CT – computed tomography 
 
 

22 
 
Figure 2 
Management of POI 
 
POI – postoperative ileus, NGT – nasogastric tube 
 
 
 
 
 
 
 
 
 
 
 

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TABLE S1    STROBE Statement—Checklist of items that should be included in reports of cohort studies 
1 
 
Item 
No. 
Recommendation 
Page  
No. 
Relevant text from manuscript 
Title and abstract 
1 
(a) Indicate the study’s design with a commonly used term in the title or the abstract 
1,2 
 
(b) Provide in the abstract an informative and balanced summary of what was done and what 
was found 
2 
 
Introduction 
 
Background/rationale 
2 
Explain the scientific background and rationale for the investigation being reported 
4 
 
Objectives 
3 
State specific objectives, including any prespecified hypotheses 
4 
 
Methods 
 
Study design 
4 
Present key elements of study design early in the paper 
5-6 
 
Setting 
5 
Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, 
follow-up, and data collection 
5-6 
 
Participants 
6 
(a) Cohort study—Give the eligibility criteria, and the sources and methods of selection of 
participants. Describe methods of follow-up 
5-6 
 
Variables 
7 
Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. 
Give diagnostic criteria, if applicable 
- 
 
Data sources/ 
measurement 
8* 
 For each variable of interest, give sources of data and details of methods of assessment 
(measurement). Describe comparability of assessment methods if there is more than one group 
6 
 
Bias 
9 
Describe any efforts to address potential sources of bias 
- 
 

24 
 
Study size 
10 
Explain how the study size was arrived at 
5 
 
Quantitative 
variables 
11 
Explain how quantitative variables were handled in the analyses. If applicable, describe which 
groupings were chosen and why 
6 
 
Statistical methods 
12 
(a) Describe all statistical methods, including those used to control for confounding 
6 
 
 
 
(b) Describe any methods used to examine subgroups and interactions 
- 
 
 
 
(c) Explain how missing data were addressed 
6 
 
 
 
(d) Cohort study—If applicable, explain how loss to follow-up was addressed 
- 
 
 
 
(e) Describe any sensitivity analyses 
- 
 
Results 
Participants 
13* 
(a) Report numbers of individuals at each stage of study—eg numbers potentially eligible, 
examined for eligibility, confirmed eligible, included in the study, completing follow-up, and 
analysed 
8 
 
(b) Give reasons for non-participation at each stage 
8 
 
(c) Consider use of a flow diagram 
8 
 
Descriptive data 
14* 
(a) Give characteristics of study participants (eg demographic, clinical, social) and information 
on exposures and potential confounders 
8 
 
(b) Indicate number of participants with missing data for each variable of interest 
8 
 
(c) Cohort study—Summarise follow-up time (eg, average and total amount) 
8 
 
Outcome dats 
15* 
Cohort study—Report numbers of outcome events or summary measures over time 
8-9 
 

25 
 
Main results 
16 
(a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their 
precision (eg, 95% confidence interval). Make clear which confounders were adjusted for and 
why they were included 
8-9 
 
(b) Report category boundaries when continuous variables were categorized 
8-9 
 
(c) If relevant, consider translating estimates of relative risk into absolute risk for a meaningful 
time period 
- 
 
Report other analyses done—eg analyses of subgroups and interactions, and sensitivity analyses 
8-9 
 
Discussion 
Key results 
18 
Summarise key results with reference to study objectives 
10-11-12 
 
Limitations 
19 
Discuss limitations of the study, taking into account sources of potential bias or imprecision. Discuss 
both direction and magnitude of any potential bias 
12-13 
 
Interpretation 
20 
Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of 
analyses, results from similar studies, and other relevant evidence 
10-11-12-13 
 
Generalisability 
21 
Discuss the generalisability (external validity) of the study results 
- 
 
Other information 
 
Funding 
22 
Give the source of funding and the role of the funders for the present study and, if applicable, for the 
original study on which the present article is based 
 
 
 
2 
Table S1: STROBES Checklist 
3 
 
4