Specific Aims:

Aim 1: Evaluate the feasibility of intermittent feeding in intensive care unit patients who are mechanically ventilated.

Aim 2: Evaluate the safety and patient tolerance of intermittent feeding in intensive care unit patients who are mechanically ventilated.

Aim 3: Determine efficacy of intermittent feeding in provision of required nutrition in mechanically ventilated intensive care unit patients.

Aim 4: Determine association of intermittent enteral feeding with glycemic control in mechanically ventilated intensive care unit patients.

With the advent of the feeding pump, default enteral nutrition schedules in many medical intensive care units has shifted from intermittent or bolus feeding to continuous feeds. Clinical studies suggest that each of these strategies of providing nutrition is safe for patients with no significant difference in glycemic control or adverse effects. There is also data to suggest that approximating a more physiologic nutrition schedule with periods of feeding and periods of fasting may optimize gastrointestinal and metabolic hormonal feedback loops thereby effecting outcomes such as gastrointestinal motility, protein synthesis, and glycemic control, among others. Circadian rhythm research supports a temporally restricted period of feeding as well. Furthermore, periods of scheduled fasting will allow for provision of care that is incompatible with enteral feeds, without interrupting administration of nutrition (for example, procedures or testing, incompatible medications, etc).

Aims 1 and 2 will clarify whether an intermittent enteral nutrition schedule is acceptable to ICU staff and patients. Aims 3 and 4 will test whether this enteral feeding schedule is effective in providing patients with required nutrition and acceptable glycemic control.

This pilot will set the stage for a randomized controlled trial further investigating superiority of intermittent feeding as compared with the current standard of continuous feeding.

Inclusion Criteria:

• Medical intensive care unit patients located in Yale-New Haven Hospital, York Street campus, North Pavilion 9 or 10.
• Hospitalized for less than or equal to 72 hours.
• Patients who are mechanically ventilated via endotracheal tube for at least 24 hours.
• Patients must have enteral access (nasogastric tube, orogastric tube).
• Team plans to initiate tube feeds.

Exclusion Criteria:

• Prior upper gastrointestinal surgery (including but not limited to gastric bypass surgery, gastric banding, complete or partial gastrectomy, Whipple procedure; cholecystectomy is acceptable).
• Chronic enteral nutrition (prior to current admission).
• History of significant esophageal dysmotility (history of GERD is acceptable).
• Unable to have head of bed elevated at least 30 degrees while intubated and being fed (this is standard protocol).
• Enteral access terminates post-pyloric (ie nasojejunal or jejunostomy tubes are to be excluded).
• Pre-existing percutaneous gastrostomy tube.
• History of small bowel obstruction or ileus on current admission.
• History of gastroparesis.
• Clinical care team is not planning to initiate enteral nutrition.
• At risk of refeeding syndrome.
• Pregnant patients.
• Patients receiving neuromuscular blockade.
• Patients with glycemic emergency (HHNK, DKA, severe hypoglycemia resulting in MICU admission).
• Patients otherwise excluded by the treating physician.