Which of the following are factors that affect the measurement of GRVs?

• A. Body position; Type of feeding tube; Location of the tip of the feeding tube
• B. Time of day; Patient age; Diet
• C. Room temperature; Hydration status; Medication timing
• D. Type of feeding formula; Patient religion; Room color

Answer: (A)

Gastric residual volume measurements are highly sensitive to how the tube is placed and how the aspiration is performed. Body position changes how easily gastric contents drain toward the tip of the tube, so different positions can yield different residual volumes. The type of feeding tube matters because tubes differ in design, lumens, and sideholes, which affects how effectively you can aspirate contents. The exact location of the tip is crucial: if the tip sits in the stomach, you’re measuring true gastric residuals; if it’s in the duodenum or beyond, aspirated volumes won’t reflect gastric contents and the measurement becomes unreliable.

Choices like time of day, patient age, and diet don’t directly alter the measurement technique or tube placement, though they can influence digestion or tolerance overall. Similarly, room temperature, hydration, medication timing, feeding formula type, or other factors may affect physiology but not the fundamental accuracy of GRV measurement via aspiration from the stomach.