Ryles Tube Feeding Dose Determination
Initial Feeding Rate
Start continuous nasogastric tube feeding at 10-20 mL/hour using a standard 1 kcal/mL formula, then advance by 10-20 mL increments every 8-12 hours based on tolerance. 1, 2
Age-Based Starting Protocols
For pediatric patients, use weight-based calculations 1:
- Infants (0-1 year): Start at 10-20 mL/h or 1-2 mL/kg/h, advance by 5-10 mL every 8 hours, targeting 21-54 mL/h or 6 mL/kg/h 1
- Children (1-6 years): Start at 20-30 mL/h or 2-3 mL/kg/h, advance by 10-15 mL every 8 hours, targeting 71-92 mL/h or 4-5 mL/kg/h 1
- Adolescents (6-14 years): Start at 30-40 mL/h or 1 mL/kg/h, advance by 15-20 mL every 8 hours, targeting 108-130 mL/h or 3-4 mL/kg/h 1
- Adults (>14 years): Start at 50 mL/h or 0.5-1 mL/kg/h, advance by 25 mL every 8 hours, targeting 125 mL/h 1
Adult Target Calculations
Calculate total daily energy needs at 25-30 kcal/kg ideal body weight per day, with protein requirements of 1.2-1.6 g/kg/day depending on nutritional status. 2
- For a 70 kg patient, this translates to 1750-2100 kcal/day and 84-112 g protein/day 2
- Using standard 1 kcal/mL formula, the goal rate would be approximately 73-88 mL/hour for continuous feeding 2
- The minimum safe threshold is 1500 kcal/day (approximately 63 mL/hour continuous) to ensure adequate micronutrient provision 3
Critical Advancement Guidelines
The time to reach target intake typically requires 5-7 days due to limited intestinal tolerance—do not rush advancement. 1, 2
Monitoring During Advancement
- Check gastric residual volumes every 4 hours initially; if exceeding 200 mL, hold advancement and reassess 1, 2
- Assess for feeding intolerance signs: abdominal distension, nausea, vomiting, diarrhea 1, 2
- Position patient at ≥30° elevation during feeding and for 30 minutes after to minimize aspiration risk 3, 2
Special Populations
Malnourished Patients
In severely malnourished patients, start at the lower end of the range (10 mL/hour) and advance more cautiously to prevent refeeding syndrome. 2
- Monitor plasma phosphate daily; a 30% drop indicates refeeding syndrome requiring feed rate reduction and high-dose thiamine 4
- These patients may require 7-10 days to reach target rates 1
Post-Surgical Patients
Initiate feeding within 24 hours after major surgery at 10-20 mL/hour. 1
- Early feeding (within 24 hours) reduces infections and shortens hospital stay 1
- Starter regimens using diluted feeds are unnecessary and risk infection 1
Patients with Normal Recent Intake
In patients who have maintained reasonable nutritional intake in the last week, starter regimens are unnecessary—begin at 20 mL/hour and advance more rapidly. 1
Formula Selection
Use standard whole protein formulas (1 kcal/mL) for most patients; specialized formulas are rarely superior. 1
- Standard formulas can be administered via fine bore (5-8 French gauge) nasogastric tubes 1
- High-energy formulas (1.5 kcal/mL) should be reserved for patients unable to tolerate full volumes or requiring fluid restriction 4
- Kitchen-made blenderized diets are not recommended due to infection risk and tube clogging 1
Common Pitfalls to Avoid
- Never dilute commercial formulas—this increases infection risk and creates osmolality problems 1
- Do not delay feeding initiation—delayed nutritional support increases complications, prolongs hospital stay, and increases mortality 2
- Avoid overfeeding in the acute phase—match energy to expenditure only after day 4-7, not immediately 4
- Do not use weighted nasogastric tubes—there is no evidence they improve placement or position maintenance 1
Position Verification
Check nasogastric tube position using pH testing (<5.5 indicates gastric placement) prior to every use; x-ray confirmation is not routinely required for NG tubes. 1