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Tolerability and Safety of Enteral Nutrition in Critically Ill Patients Receiving Intravenous Vasopressor Therapy
Study Question: Is the provision of enteral nutrition safe in critically ill patients who require hemodynamic support with vasopressor therapy?
Study Description: This was a single-center, retrospective study of all adult ICU patients from January to December, 2011. Inclusion criteria included concomitant receipt of “tube-feeding volume” enteral nutrition (EN) and use of at least one IV vasopressor (dopamine, epinephrine, norepinephrine, phenylephrine, or vasopressin). Tolerability was also evaluated based on the specific vasopressor used and equivalent norepinephrine doses established in previously published literature. The primary study outcome was tolerance of EN, defined as the composite of gastric residuals ≥ 300 mL, emesis, positive finding on KUB or abdominal CT scan, and bowel ischemia or perforation.
Results: A total of 259 unique patients (346 episodes) were included in the final analysis. Among all episodes, overall EN tolerance was observed in 74.9% of cases. The median duration of overlap was shorter in patients who tolerated EN (26 vs. 65 hours; p = 0.0002). Patients who tolerated EN also were less likely to experience a rise in serum lactate compared to those who did not tolerate EN (25.5% vs. 46.0%, p = 0.0003). Tolerability based on the specific vasopressor used was also reported. Patients were more likely to tolerate EN if they were not prescribed vasopressin (77.9% vs. 58.9%; p = 0.0027) or dopamine (77.6% vs. 63.8%; p = 0.018). Patients who tolerated EN received a lower maximum norepinephrine equivalent dose compared with those who did not (12.5 vs. 19.4 mcg/min; p = 0.0009)
Conclusion(s): EN is relatively well tolerated in patients who received vasopressors. Tolerability was less likely in patients who received higher doses of vasopressors and in those who received either dopamine or vasopressin.
Perspective: This is a relevant study that seeks to answer a clinically relevant dilemma. Previous literature on the topic has been limited by small sample sizes and lack of patient diversity (primarily consisting of cardiac surgery patients). Current guideline recommendations from A.S.P.E.N. and SCCM only provide weak recommendations pertaining to the practice of providing patients with EN while on vasopressors, noting that it would be appropriate to hold EN in patients receiving “high-dose” catecholamine agents. However, the guidelines and data do not well define “high-dose” or which specific agents may pose greater harm. The current population was a diverse group consisting of medical, cardiac surgery, neuroscience, surgical/trauma, coronary, burn, and transplant patients, and the study found that EN was generally well tolerated in most patients. The study provided some elucidation of a dose-relationship and whether they are differences between specific vasopressors. Limitations associated with retrospective studies apply.