Monitoring gastric residuals in ICU patients: Does it prevent ventilator-associated pneumonia?

One discussion this week involved monitoring gastric residuals in ICU patients.

Reference: Reignier J, et al. Effect of not monitoring residual gastric volume on risk of ventilator-assisted pneumonia in adults receiving mechanical ventilation and early enteral feeding: a randomized control trial. JAMA. 2013 Jan 16;309(3):249-56. doi: 10.1001/jama.2012.196377.

TRIAL REGISTRATION: Identifier: NCT01137487.

Summary: Monitoring of residual gastric volume is recommended to prevent ventilator-associated pneumonia (VAP) in patients receiving early enteral nutrition. However, studies have challenged the reliability and effectiveness of this measure.

DESIGN, SETTING, AND PATIENTS: Randomized, noninferiority, open-label, multicenter trial conducted from May 2010 through March 2011 in adults requiring invasive mechanical ventilation for more than 2 days and given enteral nutrition within 36 hours after intubation at 9 French intensive care units (ICUs); 452 patients were randomized and 449 included in the intention-to-treat analysis (3 withdrew initial consent).

INTERVENTION: Absence of residual gastric volume monitoring. Intolerance to enteral nutrition was based only on regurgitation and vomiting in the intervention group and based on residual gastric volume greater than 250 mL at any of the 6 hourly measurements and regurgitation or vomiting in the control group.

RESULTS: In the intention-to-treat population, VAP occurred in 38 of 227 patients (16.7%) in the intervention group and in 35 of 222 patients (15.8%) in the control group (difference, 0.9%; 90% CI, -4.8% to 6.7%). There were no significant between-group differences in other ICU-acquired infections, mechanical ventilation duration, ICU stay length, or mortality rates. The proportion of patients receiving 100% of their calorie goal was higher in the intervention group (odds ratio, 1.77; 90% CI, 1.25-2.51; P = .008). Similar results were obtained in the per-protocol population.

CONCLUSION AND RELEVANCE: Among adults requiring mechanical ventilation and receiving early enteral nutrition, the absence of gastric volume monitoring was not inferior to routine residual gastric volume monitoring in terms of development of VAP.

The authors further conclude that “eliminating residual gastric volume monitoring from standard care may have beneficial effects. First, in the present study, absence of residual gastric volume monitoring was associated with improved enteral nutrition delivery. High residual gastric volume values often lead to enteral nutrition discontinuation, which in turn causes underfeeding with increases in morbidity and mortality rates. We found no difference in mortality rates. However, our enteral nutrition protocol was more aggressive than previously reported protocols: enteral nutrition was started at the rate required to meet the calorie target and was stopped gradually in the event of intolerance. Moreover, enteral nutrition solution lost by vomiting, being discarded, or both was not measured, thus resulting in potential overestimation of delivered calories. These factors may have attenuated any mortality difference related to differences in delivered enteral nutrition volume” (p.255).

Metabolic effects of octreotide

One discussion this week involved the effects of octreotide.

Reference: Octreotide: a drug often used in the critical care setting but not well understood. Chest. 2013 Dec;144(6):1937-1945. doi:10.1378/chest.13-0382.

Summary: While a majority of octreotide is metabolized by the liver, 30-35% of octreotide acetate is excreted in the urine. Thus, octreotide accumulates in patients with moderate to severe renal or hepatic insufficiency.

Compared with SST-14, it exhibits 45-fold more potent inhibition of growth hormone, 11-fold more of glucagon, and 1.3-fold more insulin secretion.



Octreotide inhibits insulin secretion in the following ways (p.1943):

  • Binds to SSTR-5 present on pancreatic B islet cells, inhibiting the formation of cAMP and reducing influx of calcium into the cytoplasm, thus preventing insulin secretion.
  • Inhibition of direct phosphorylation of specific proteins required for secretion of insulin-containing vesicles.

Additional reading:  Adabala M, et al. Severe hyperkalaemia resulting from octreotide use in a haemodioalysis patient. Nephrology, Dialysis, Transplantation. 2010 Oct;25(10):3439-3442. doi:10.1093/ndt/gfq381.