708 Enteral Nutrition Initiation During Periods of Vasopressor Requirements and Elevated Lactate Levels

Abstract

Abstract Introduction Nutrition is a core component of care for the critically ill burn patient. The Society for Critical Care Medicine recommends initiating enteral nutrition (EN) within 4–6 hours of injury for burn patients, while simultaneously recommending waiting until hemodynamic stability is achieved for critical care patients. The goal of this analysis was to evaluate tolerance of EN during periods of different pressor requirements and lactate levels. Methods We performed a retrospective evaluation on all burn patients admitted to our intensive care unit in 2018 who received EN. This performance improvement project was approved by our regulatory compliance division. Lactate levels and vasopressor use just prior to EN initiation, the highest EN rates and gastric residual volumes during the 24 hours after initiation, and ischemic bowel and aspiration after EN initiation were recorded. Significance was accepted at p< 0.05. Results EN was initiated at 30 ± 20 hours after admission in 58 patients with the following characteristics: 47 ± 19 years old, 29 ± 24% TBSA burn, 13 mechanical ventilator days (IQR: 5–30), 15% mortality. The highest EN rate reached was 100 ± 49 mL/hr during the first 24 hours after initiation. Lactate levels were 1.9 mmol/L at the time of EN initiation (IQR: 1.6–2.4 mmol/L), with a maximum of 4.9 mmol/L. Lactate levels did not have a significant correlation with gastric residual volumes (p=0.532). Most (59%) patients did not have vasopressor requirements, but 21% required vasopressin only, 2% required norepinephrine only, and 19% required a combination of vasopressin and norepinephrine. Those who received norepinephrine received 3.3 ± 1.7 mcg/min, with a maximum of 7 mcg/min. There was a significant difference in gastric residual volumes between patients who had no vasopressor requirements compared to those who required vasopressors [13 mL (IQR: 0–200 mL) vs. 240 mL (IQR: 21–430 mL), p=0.014)]; however, the number of patients with gastric residual volumes over 500 mL was not significantly different (3% vs. 17%, p=0.149). When examining patients receiving vasopressin alone, there was a significant but weak correlation between vasopressin dose and gastric residual volumes (p=0.047, R2=0.339); however, when examining only patients receiving norepinephrine, there was no correlation between norepinephrine dose and gastric residual volumes (p=0.905, R2=0.002). There was 1 episode of aspiration and 1 episode of ischemic bowel, both of which occurred 3 days after EN initiation. EN was initiated without vasopressors running and lactate levels were normal in both cases. Conclusions The majority of patients tolerated EN initiation with vasopressor dosing of norepinephrine up to 7 mcg/min and lactate up to 4.9 mmol/L. Applicability of Research to Practice We found no indication for holding EN for lactate levels under 5 mmol/L and norepinephrine under 8 mcg/min.