The recovery of transit after surgery is an important parameter in postoperative evaluation. It generally reflects simple postoperative outcomes and allows the patient to return home.

The quality of gas recovery after surgery has not been studied to our knowledge, but it is not uncommon for an operated patient to emit some gas considered as a recovery of transit when it is ultimately a false transit preceding a postoperative ileus. Furthermore, intestinal gases and their composition reflect the intestinal microbiota. This microbiota has been shown to be predictive of the appearance of an operative complication. As the analysis of this microbiota cannot be carried out routinely, it is important to be able to use a reflection of this microbiota in routine practice and to correlate it with the surgical outcomes. Intestinal gas therefore seems to be the tool of choice.

The main objective is to evaluate the association between the appearance of an operative complication and the resumption of gas transit qualified according to its quantity and quality.

The secondary objectives are to compare the quantity and quality of gases pre- and post-operatively and to define a predictive score for surgical complications, based on the number and quality of post-surgical gases.

Data regarding gas transit are collected by the patient in a questionnaire the two days before the surgery and until the patient leaves hospital (or until day 15 post-operative if the patient is still hospitalized).

Data regarding possible complications ((defined according to Dindo-Clavien as any deviation from the expected postoperative outcomes within 90 days following surgery) are collected throughout the hospital stay (day 0 : surgery to day 15 post-operatively), during the post-operative consultation (day 30) and during a telephone call to the patient (day 90).

The expected results are to highlight a correlation between the quality/quantity of gases and post-operative outcomes. A predictive score for complications could then be proposed and validated during this study.

Inclusion Criteria:

• Patients ≥18 years old
• Indication for open or laparoscopic abdominal surgery
• Whose expected length of stay is ≥ 2 days

Non Inclusion Criteria:

• Patients requiring a stomy on the initial surgery
• Need for immediate postoperative intensive care
• Emergency surgery
• Patient not knowing how to read or write
• Poor understanding of the French language
• Person deprived of liberty by judicial or administrative decision
• Person subject to psychiatric care under duress
• Person subject to a legal protection measure
• Person unable to express consent
• Person objecting to participating in research

Exclusion Criteria:

-Immediate post-operative intensive care

The patients will be included in the hospital they will be operated on