The heavily debated topic of “should we check residuals or should not?” A lot of institutions have implemented checking residuals into nursing policy. Initially, monitoring of gastric residual was recommended to help prevent ventilator-associated pneumonia (VAP) and for the evaluation of feeding intolerance. The theory behind checking residuals is based on the assumption that a full stomach predisposes ventilated patients to aspiration and VAP. Based on this, experts initially suggested checking residuals, typically every 4-6 hours, for the large quantities of feed and gastric content. However, no studies have shown that increased gastric volume increases VAP risk, ICU-acquired infections, or aspiration.
Tube feeding intolerance has a wide definition, but most commonly is defined as high gastric residual, increased abdominal size/distention, discomfort or emesis. There is a wide range in what was considered as high residual, anywhere from 100-500 cc, showing no clear consensus on what number to use. A recent survey took a look at the frequency of tube feeding intolerance and mechanically ventilated patients. It noted that intolerance is more common with those who are mechanically ventilated and increases with the number of ventilated days and ICU LOS. Intolerance was also noted to be associated with decreased nutritional delivery and worse clinical outcomes.
What is a VAP?
We won’t dive into too much detail here, but VAP is considered hospital-acquired pneumonia that has occurred 48 hours after a patient has been intubated. VAP can be suspected when a patient develops a new infiltrate on CXR, increased ventilator settings, increased tracheal secretions, leukocytosis, new fever, and clinical judgment of the LIP.
The stomach is ultimately a reservoir, and this reservoir allows slow emptying into the small bowel. The slow emptying of the stomach occurs at 5-15 cc and is designed to help with absorption in the gut. We must remember that endogenous and exogenous factors go into the gastric volume (food, water, medications, bile, etc.). During any given meal, the stomach can expand upwards of 1,000 cc. After 1,000 cc, pressure can increase, causing distention and discomfort. Complete emptying after a meal can occur around 3-4 hours. During a fasting state, the stomach can secrete upwards of 500-1,500 cc of bile and content alone, and in a fed state upwards of 2,500 cc. This is a lot of mixed secretions and bile content that the body needs that can be contributing to our “high residuals.”
Show them the studies?
The REGANE study compared the effects of increasing gastric residual volume and receiving an adequate amount of nutrition. Montejo et al. studied 329 mechanically ventilated patients using a diet volume ratio (diet received/diet prescribed) and compared this to GI complications, VAP, days on mechanical ventilator, and ICU length of stay. Results were that there were no essential differences in a residual limit of 500 cc vs. 200 cc. In addition, the higher limit of 500 cc was not associated with an increase in GI complications, VAP, mechanically ventilated days, and ICU LOS.
The CRICS group study took whether VAP had a higher association with higher residual gastric volume. This study was a randomized multicenter trial in nine French ICUs that enrolled 449 patients. Two groups in this study were no monitoring of gastric residual vs. routine (Q. 4hr with a cut off of 250 cc) checks in patients receiving mechanical ventilation. Outcomes that they measured were patients with at least one VAP episode. Reignier et al. showed no significant difference between study groups in mechanically ventilated days, ICU LOS, ICU acquired infections, or mortality rates.
The newest American Society of parenteral and enteral nutrition (ASPEN) guidelines recommend NOT using gastric residual volumes as a part of routine care for those patients receiving enteral nutrition in the ICU. This is due to the fact that frequent checking of gastric residuals can lead to a hold on enteral nutrition related to “high residuals”. This causes patients to not reach their caloric goals, thereby a possible worsening in outcomes for your patient. In summary patients who do not get their total caloric needs show worse outcomes.
If there are clinical signs of intolerance such as abdominal distention, constipation, and/or pain, the bedside warrior can ask for further evaluation. This evaluation includes KUB or CT scan, and maybe the addition of prokinetic medications and a bowel regimen to help with emptying.
Some studies have looked at early enteral/parenteral nutrition vs. delayed nutritional intake. What we have found is that early administration of nutrition reduced mortality and pneumonia compared to delayed administration. In addition, critical care medicine released a meta-analysis in 2018 that showed improvement in clinical outcomes when early nutrition was established. Improvements are related to preserved gut integrity, leading to fewer infections, fewer organ failures, and a reduction in sepsis occurrences. Preventing any number of these complications can only help improve survival and reduce hospital length of stay.
- High gastric residuals are the most common reason enteral feeding goals are not met. 80% of noted high residuals are isolated events.
- We do not need to be checking residuals.
- Especially do not check the residual on small-bore feeding tubes (i.e., Corpak)
- There is no association noted with ICU-acquired infections and high gastric residuals.
- Early nutritional support reduces patient mortality and LOS. And, unmet caloric needs lead to poorer outcomes.
- If clinical signs of intolerance (constipation, distention, discomfort, etc.) exist, advocate further evaluation.
- Make sure the patient has a bowel regimen and limit opioids that could be causing constipation.
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- Heyland DK, Ortiz A, Stoppe C, et al. Incidence, Risk Factors, and Clinical Consequence of Enteral Feeding Intolerance in the Mechanically Ventilated Critically Ill: An Analysis of a Multicenter, Multiyear Database. Crit Care Med. 2021;49(1):49-59. doi:10.1097/CCM.000000000000471
- Koenig SM, Truwit JD. Ventilator-associated pneumonia: diagnosis, treatment, and prevention. Clin Microbiol Rev. 2006;19(4):637-657. doi:10.1128/CMR.00051-05
- McClave SA, Lukan JK, Stefater JA, et al. Poor validity of residual volumes as a marker for risk of aspiration in critically ill patients. Crit Care Med. 2005;33(2):324-330. doi:10.1097/01.ccm.0000153413.46627.3a
- McClave SA, Taylor BE, Martindale RG, et al. Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) [published correction appears in JPEN J Parenter Enteral Nutr. 2016 Nov;40(8):1200]. JPEN J Parenter Enteral Nutr. 2016;40(2):159-211. doi:10.1177/0148607115621863
- Montejo JC, Miñambres E, Bordejé L, et al. Gastric residual volume during enteral nutrition in ICU patients: the REGANE study. Intensive Care Med. 2010;36(8):1386-1393. doi:10.1007/s00134-010-1856-y
- Poulard F, Dimet J, Martin-Lefevre L, et al. Impact of not measuring residual gastric volume in mechanically ventilated patients receiving early enteral feeding: a prospective before-after study. JPEN J Parenter Enteral Nutr. 2010;34(2):125-130. doi:10.1177/0148607109344745
- Pu H, Doig GS, Heighes PT, Allingstrup MJ. Early Enteral Nutrition Reduces Mortality and Improves Other Key Outcomes in Patients With Major Burn Injury: A Meta-Analysis of Randomized Controlled Trials. Crit Care Med. 2018;46(12):2036-2042. doi:10.1097/CCM.0000000000003445
- Reignier J, Mercier E, Le Gouge A, et al. Effect of not monitoring residual gastric volume on risk of ventilator-associated pneumonia in adults receiving mechanical ventilation and early enteral feeding: a randomized controlled trial. JAMA. 2013;309(3):249-256. doi:10.1001/jama.2012.196377
- Yasuda H, Kondo N, Yamamoto R, et al. monitoring of gastric residual volume during enteral nutrition. Cochrane Database Syst Rev. 2019;2019(5):CD013335. Published 2019 May 14. doi:10.1002/14651858.CD013335