Fluids, Electrolytes, Acid-Base Disorders, and Nutrition Support
iv.
Biochemical evidence for EFAD (the “classic definition” is an increased triene/tetraene
[eicosatrienoic acid/arachidonic acid] ratio greater than 0.2) occurs in 30%, 66%, 83%,
and 100% of patients after 1, 2, 3, and 4 weeks of fat-free “full-calorie, continuous” PN
poor wound healing) usually do not occur until about 2 weeks after biochemical evidence
in adults. Therefore, in most adults, the earliest appearance of EFAD is after about 3 weeks
of fat-free full-calorie continuous PN. Because the investigators initiated ILE soon after the
biochemical appearance of EFAD, only 2 of 32 patients developed clinical evidence suggestive
of EFAD. EFAD can occur much sooner for infants and children. Patients with obesity
receiving hypocaloric high-protein therapy can maintain normal plasma fatty acid profiles for
up to 5 weeks (J Nutr Biochem 1994;5:243-7). Cyclic PN has been suggested to mobilize lipid
from endogenous depots, but conclusive data are lacking and cyclic PN should be avoided in
critically ill patients, as previously discussed.
Serum triglyceride concentration should be monitored at least weekly and more often for those
with proven or suspected impaired triglyceride clearance (consider temporarily withholding
lipid emulsion when serum triglyceride approaches or exceeds 400 mg/dL) (Nutr Clin Pract
2020;35:769-82).
vi.
Predisposing conditions that may result in impaired clearance of triglycerides:
| (a) | Excessive lipid intake (propofol and clevidipine are 2 drugs commonly used in the ICU |
|---|
setting that contain lipids within their preparation. Propofol is a 10% emulsion containing
1.1 kcal/mL, and clevidipine is a 20% emulsion containing 2 kcal/mL)
| (b) | Acute pancreatitis |
|---|---|
| (c) | Uncontrolled diabetes |
| (d) | Liver failure |
| (e) | Kidney failure (decreased lipoprotein lipase activity, carnitine deficiency with long-term |
hemodialysis patients)
| (f) | End-stage sepsis (multisystem organ failure) |
|---|---|
| (g) | History of hyperlipidemia |
| (h) | Obesity |
| (i) | HIV (occurred even before current antiretroviral therapy) (Am J Med 1989;86:27-31) |
| (j) | Pregnancy |
| (k) | Small-for-gestational-age neonates (carnitine synthesis is maturational-dependent) |
Electrolyte requirements (see the Fluids and Electrolytes section)
When initiating nutrition, particularly in patients with prolonged malnutrition and at
high nutrition risk, the occurrence of profound electrolyte abnormalities (hypokalemia,
hypomagnesemia, and hypophosphatemia) typically reflects refeeding syndrome. To prevent
refeeding syndrome, consider initiating nutrition at hypocaloric doses and titrating toward goal
over 1 to 3 days. If a patient experiences refeeding syndrome, recommendations are to slow the
rate of feeding and aggressively replete electrolytes according to guideline recommendations.
Vitamins
One full dose of multiple vitamins for infusion (i.e., 10 mL/day) should be included in every
bag of PN with few exceptions.
ii.
Conservative supplementation doses (i.e., higher than basal needs to replace losses) of certain
vitamins may be safely added to most PN admixtures (e.g. thiamine or folic acid).
iii.
Repletion doses of vitamins (i.e., to correct a known deficiency) should be provided separately
from the PN admixture because of numerous possible interactions affecting compatibility and
stability of the admixture (JPEN J Parenter Enteral Nutr 2022;46:273-99).
Trace minerals