Disruption of the normal gastrointestinal (GI) motility is a well-known consequence of major surgery. The pathophysiology behind this phenomenon is not fully understood but involves the autonomic nervous system as well as a systemic stress response to surgery. A number of factors interfere with GI motor activity, such as the direct manipulation of intestines during surgery and the use of opioid analgesia. Post-operative ileus (POI) refers to a delay in regaining GI motility beyond the anticipated normal duration of time. Signs and symptoms include nausea, vomiting, abdominal distention, the absence of flatus or stool in the preceding 24 hours, and/or an inability to tolerate oral intake. The incidence of POI in abdominal surgery is estimated to be approximately 10%-30%. Beyond increased patient discomfort and distress, the development of POI is associated with increased healthcare costs.

Coffee is a popular beverage: two thirds of Canadians are coffee drinkers, averaging approximately 3.2 cups per day. Coffee is composed of hundreds of chemicals, many with demonstrated pharmacologic effects. The most well-known of these compounds is caffeine, known to exert a stimulatory effect on the cardiovascular and nervous system. A recent systematic review of 7 randomized controlled trials (N=606 colorectal and gynecology surgical patients) determined that the consumption of coffee reduced the time of several measures of GI recovery, such as time to tolerance of food, without any increased rate of complications or adverse events although overall, the evidence was graded as low to moderate certainty, and further confirmatory studies are needed. In this trial, patients aged 18 years or higher who undergo laparoscopic or open abdominal surgery, with an estimated length of stay > 24 hours will be randomized to receive approximately one cup of either coffee, decaffeinated coffee, or warm water, three times daily. This trial will be conducted under the IMPACTS (Innovative, Multicentre, Patient-centred Approach to Clinical Trials in Surgery) program umbrella and will follow IMPACTS methodology. For the Vanguard trial, the aim is to determine the feasibility of conducting a definitive trial. Future outcomes of interest include: time to first flatus, time to first bowel movement, placement of an NG tube, length of stay in hospital, 30-day mortality, and 30-day postoperative complications.

Background/rationale: The development of POI is a common complication of surgery that is detrimental to patient well-being and ultimately leads to significant healthcare costs. Coffee is a popular drink among Canadians and appears to exert a positive effect on GI motility. This beverage may provide an inexpensive, easily administered and well-tolerated intervention to accelerate post-operative GI recovery, and thus reduce POI. The current literature, while promising, is insufficient and merits further investigation in the form of a high-quality randomized controlled trial.

Objectives: Before embarking on a definitive RCT, this pilot trial has five specific feasibility objectives:

1. To assess our ability to accrue patients using the IMPACTS Program platform, at multiple institutions, over the course of one year.
2. To assess our ability to adaptively randomize patients and deliver the randomized assignment using the IMPACTS Program platform, over the course of one year.
3. To assess our ability to collect complete data directly from participants (patients and clinicians) on time to first flatus and time to first bowel movement over the course of one year.
4. To examine our ability to carry out data linkages using the IMPACTS Program platform over the course of one year.
5. To estimate the change in time to first flatus to inform the sample size calculation for the definitive trial.

Study design: This is a multicentre, pragmatic, 3-arm parallel group Vanguard feasibility randomized controlled trial. Patients will be randomly assigned to consume coffee, decaffeinated coffee, or warm water. If feasibility is demonstrated during the pilot trial, we will plan to conduct a definitive trial. If there are only minimal changes to the protocol, we will include data from the pilot phase into the definitive trial analysis (i.e. a Vanguard design).

Inclusion Criteria:

• Age ≥ 18 years
• Planned elective laparoscopic or open abdominal surgery
• Patient is scheduled to remain in hospital for at least one night, post-operatively

Exclusion Criteria:

• Known intolerance to coffee or caffeine
• Unwilling to stop current caffeine consumption (coffee or tea) during trial