Role of Nutrition Support in Adult Cardiac Surgery

A Consensus Statement From an International Multidisciplinary Expert Group on Nutrition in Cardiac Surgery

Christian Stoppe; Andreas Goetzenich; Glenn Whitman; Rika Ohkuma; Trish Brown; Roupen Hatzakorzian; Arnold Kristof; Patrick Meybohm; Jefferey Mechanick; Adam Evans; Daniel Yeh; Bernard McDonald; Michael Chourdakis; Philip Jones; Richard Barton; Ravi Tripathi; Gunnar Elke; Oliver Liakopoulos; Ravi Agarwala; Vladimir Lomivorotov; Ekaterina Nesterova; Gernot Marx; Carina Benstoem; Margot Lemieux; Daren K. Heyland

Disclosures

Crit Care. 2017;21(131) 

In This Article

Optimal Time Point for Perioperative Nutrition Therapy in Cardiac Surgery Patients

Determining the ideal time to start feeding in relation to cardiac surgery represents a crucial factor for nutritional support to be effective. Until now, only a few studies have addressed this question. In regards to timing, the following time windows may be of particular relevance:

  • Preoperative: at least 2–7 days before surgery

  • Early preoperative: ≤24 hours before surgery

  • Early postoperative: ≤24 hours after ICU admission

  • Postoperative: >24 hours after ICU admission

One challenging aspect facing perioperative nutritional support is the fact that over half the patients having cardiac surgery are admitted as outpatients on the day of surgery, creating a significant challenge to preoperative nutritional risk assessment and timely intervention. If a beneficial role for a preoperative approach is determined, clinicians will need to overcome this challenge and consider an outpatient approach to optimize the nutritional status prior to admission. In the meantime, the best assessment and treatment window for now is immediately after surgery or soon after arrival at the ICU. Due to the limited evidence on the preoperative or early postoperative identification of these patients, current practice currently only allows practitioners to initiate the nutrition therapy on an individualized patient-tailored consideration.

Enteral vs Parenteral Nutrition in Cardiac Surgery Patients

Considering international guidelines, there is a strong consensus and most experts will report that EN is always preferred to PN. Following cardiac surgery, critically ill patients are frequently on vasopressor treatment because of an inflammatory response syndrome, vasoplegia, and/or postoperative low output syndrome due to myocardial stunning. The need for vasopressor support further results in marked changes in energy expenditure and frequent intolerance to oral feeding, leading to significant energy/protein deficits and increased risk of malnutrition. Although proven safe,[28] EN is often thought to be contraindicated and considered as harmful especially in hemodynamically unstable patients on large doses of inotropes and/or vasopressors, leading to a widespread use of PN in clinical practice. Berger et al. were among the first to provide evidence from a small cohort on the feasibility and safety of early nutrition support in patients after cardiac surgery. Using a well-established paracetamol absorption test, the investigators demonstrated that hypocaloric EN was feasible in such patients with altered hemodynamic status.[28] Kahlid et al. demonstrated in a large scale, multi-center, observational study that mechanically ventilated, vasopressor-dependent patients (mixed population) had a significant survival advantage when EN feeding was started within the first 48 hours after ICU admission, compared to those receiving EN feeding later than 48 hours.[29] Furthermore, in a subgroup analysis, they demonstrated that the sickest patients (on multiple vasopressors compared to those on one vasopressor only) had a more pronounced survival advantage. In addition, nutrition support was demonstrated to be feasible in patients with extracorporeal life support systems (ECLS). All patients on ECLS (in venovenous or venoarterial mode) were fed using existing protocols that emphasize early EN in preference over PN or delayed EN.[30] Notably, the use of paralysis and sedation did not affect feeding tolerance regarding the time to reach goal rate, incidence of intolerance in the first 5 days, or time until first observed bowel motion. In contrast, actual guidelines recommend withholding EN nutrition in hemodynamically unstable patients, though this is primarily based on preclinical and observational studies.[31] The rationale behind this is that the hemodynamic failure may compromise the splanchnic blood flow, causing intestinal ischemia,[32] which is associated with high mortality.[33,34]

Given the current evidence, vasopressor use per se is not a contraindication to EN. In hemodynamically unstable critically ill or cardiac surgery patients, there is at least some evidence that early EN is absorbed and metabolized without any harmful effect on systemic measurements of oxygenation and perfusion and supportive evidence from a large-scale observational study that this translates into an advantage in terms of mortality.[28] Therefore, early EN may be beneficial in patients after initial resuscitation from critical organ failure. Future well-designed studies are needed for an adequate assessment of this important question.

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