Background: A concentrated fat emulsion (Intralipid 30%) with a phospholipid/triglyceride ratio of 0.04 was tested for clinical tolerance and metabolic effects in the short-term parenteral nutrition of septic and trauma critically ill patients and compared with Intralipid 20% (phospholipid/triglyceride ratio of 0.06).

Methods: This was a prospective, randomized, multicenter study in the intensive care units in 10 university hospitals, including 90 adult patients in 2 groups: 55 septic and 35 trauma patients. Patients in each group were randomly divided into 2 subgroups according to the fat emulsions administered (1.4 g/kg per day) as part of the calories for at least 6 days of continuous total parenteral nutrition (TPN). One subgroup was treated with 30% long-chain triglycerides (phospholipid/ triglyceride ratio: 0.04) and the other with 20% long-chain triglycerides (phospholipid/triglyceride ratio: 0.06). The parenteral nutrition formula was isocaloric and isonitrogenous with 0.25 g of nitrogen/kg per day and 40% of the nonprotein calories as fat. Clinical tolerance was assessed during the study. At baseline and after 3 and 6 days of TPN, the following biochemical parameters were measured: prealbumin, retinol-binding protein, serum albumin, hematologic, hepatic and renal function variables, triglycerides, phospholipids, total and free cholesterol, nonesterified cholesterol, nonesterified fatty acids, and lipoproteins.

Results: At baseline, no differences in age, gender, severity of the condition [Acute Physiology and Chronic Health Evaluation (APACHE II) score], or clinical chemistry were found between the subgroups. The levels of plasma proteins studied and the renal, hematologic, or hepatic function variables did not vary during the study period. Total cholesterol increased significantly, owing to esterified cholesterol, with 20% long-chain triglyceride in septic patients (baseline: 2.1 +/- 0.8 mmol/L, day 6: 2.8 +/- 0.6 mmol/L, p = .026). In septic patients receiving 20% long-chain triglycerides, plasma triglycerides had a similar behavior (baseline: 1.4 +/- 0.6 mmol/L, day 3: 2.2 +/- 0.8 mmol/L, p < .05). The very-low-density lipoprotein content of cholesterol, triglycerides, and phospholipids showed a tendency to decrease in septic patients treated with 30% long-chain triglycerides (NS). None of the emulsions induced the synthesis of lipoprotein X.

Conclusions: Our results indicate that while both fat emulsions used in the TPN of critically ill patients are clinically safe, the 30% long-chain triglyceride fat emulsion with a phospholipid/triglyceride ratio of 0.04 causes fewer lipid metabolic disturbances.