TONIC Trial Will Test Early Nutrition After Emergency Abdominal Surgery

Key Takeaways

• TONIC is a multi-center, two-arm randomized controlled trial examining early nutritional support after emergency abdominal surgery.
• The study will compare parenteral nutrition started within 48 hours with standard nutritional management that may include supplements, nasoenteric feeding, or later parenteral nutrition.
• Investigators will measure complications through discharge, track broader outcomes through 30 and 90 days, and use an internal pilot to assess feasibility.

The TONIC trial has opened as a UK-wide randomized study that will enroll 898 adults after emergency abdominal surgery. It will include patients undergoing NELA-eligible urgent or emergency laparotomy or laparoscopy. The study will test whether starting parenteral nutrition early after surgery improves recovery compared with current nutritional management. Hospitals currently use different nutritional approaches, and the optimal strategy remains uncertain. TONIC aims to clarify when and how nutritional support should begin after emergency abdominal surgery.

TONIC, short for Timing Of Nutritional Intervention after emergency laparotomy/laparoscopy, is a multi-center, two-arm randomized controlled trial. It will run across 25 NHS hospitals in the UK and enroll adults undergoing NELA-eligible urgent or emergency laparotomy or laparoscopy. England and Wales see about 21,000 such operations each year, and 90-day mortality has plateaued near 9.6% since 2021. Many patients struggle to eat for several days after major abdominal surgery, and direct evidence in emergency surgical patients remains limited. The trial is intended to address that uncertainty in this population.

Patients assigned to the intervention arm will receive parenteral nutrition within 48 hours of surgery. The comparator is standard nutritional management, which may include oral supplements, nasoenteric feeding, or parenteral nutrition after 5 days unless clinically required earlier. Standard care reflects routine local practice rather than a single fixed pathway across sites. Existing guidance recognizes possible value in early intervention without defining a clear approach for this group. TONIC will compare these two nutritional strategies in emergency abdominal surgery.

The primary outcome is the rate and severity of complications up to hospital discharge. Secondary measures extend to complications at 30 and 90 days, including infectious events such as surgical site infection and pneumonia. The study will also track function, quality of life, readmissions, cost-effectiveness, and patient-reported recovery measures and satisfaction. Together, these outcomes cover inpatient recovery as well as the period after discharge.

An internal pilot will run across six sites during the first six months before the full rollout. Investigators will use that phase to assess feasibility, recruitment rates, intervention delivery, and data completeness. TONIC is described as one of the first and largest nutritional emergency surgery trials of its kind. Support will come from the Birmingham Clinical Trials Unit and the NIHR Health Technology Assessment Programme. The first phase will focus on feasibility and delivery, as no clinical outcome data are yet available.