When should nutritional support start in post-operative mechanically ventilated patients?

From the Guidelines

Nutritional support in post-operative mechanically ventilated patients should ideally begin within 24 hours after surgery, as early enteral nutrition is preferred when possible, to minimize negative protein balance and maintain muscle, immune, and cognitive function. This approach is supported by the most recent guidelines, such as the ESPEN practical guideline: clinical nutrition in surgery 1, which emphasizes the importance of early oral feeding and avoidance of underfeeding during the postoperative course.

When initiating nutritional support, it is essential to ensure the patient has adequate hemodynamic stability, acceptable electrolyte levels, and controlled glycemia (blood glucose <180 mg/dL) 1. The goal is to provide 25-30 kcal/kg/day and 1.2-2.0 g/kg/day of protein, with enteral feeding or a combination of enteral and supplementary parenteral feeding being the first choice 1.

Key considerations include:

• Early enteral nutrition is especially relevant for surgical patients at nutritional risk, such as those undergoing upper gastrointestinal surgery 1
• Patients with severe trauma, obvious undernutrition, or inadequate oral intake for more than 10 days may benefit from early post-operative total feeding (TF) 1
• Regular reassessment of nutritional status and adjustment of feeding protocols based on tolerance and metabolic changes is crucial for optimal outcomes 1

In patients who cannot meet their caloric requirements within 7-10 days orally or enterally, postoperative parenteral nutrition is recommended, with a full range of vitamins and trace elements supplemented on a daily basis 1. By prioritizing early nutritional support, clinicians can help preserve lean body mass, support wound healing, reduce infection risk, and maintain gut barrier function, ultimately improving morbidity, mortality, and quality of life outcomes in post-operative mechanically ventilated patients.

From the Research

Timing of Nutritional Support in Post-Operative Mechanically Ventilated Patients

• The initiation of nutritional support in post-operative mechanically ventilated patients is crucial for their recovery and outcomes 2, 3.
• Early enteral nutrition has been shown to decrease complications and hospital length of stay, and improve the prognosis at discharge 2.
• A study published in 2015 found that the use of an enteral nutrition protocol led to earlier initiation of feedings and more complete nutrition in mechanically ventilated patients 3.
• The protocol resulted in 83.3% of patients receiving enteral nutrition within 24-48 hours of intubation, compared to 54.5% in the preintervention group 3.

Factors Influencing Nutritional Support

• The route of nutrition delivery can impact the adequacy of protein and energy intake in critically ill adults following liberation from mechanical ventilation 4.
• A study published in 2021 found that patients who consumed an oral diet as the sole nutrition source had lower median amounts of protein and energy consumed compared to those prescribed by dietitians 4.
• Barriers to eating, such as poor appetite, early satiety, and taste changes, can also impact nutritional intake in post-ICU patients 4.
• Erythromycin has been shown to facilitate early enteral nutrition in mechanically ventilated patients by promoting gastric emptying 5.

Recommendations for Nutritional Support

• Enteral nutrition should be initiated early in mechanically ventilated patients, ideally within 24-48 hours of intubation 2, 3.
• The use of an enteral nutrition protocol can help ensure that patients receive adequate nutrition and minimize complications 3.
• The route of nutrition delivery should be carefully considered, and strategies to enhance nutrition intake should be implemented, especially in patients who are transitioning to an oral diet 4.