Total parenteral nutrition in the critically ill patient

Context.-Nutritional support has become a standard of care for hospitalized patients, but whether total parenteral nutrition (TPN) affects morbidity a nd mortality is unclear. Objective.-To examine the relationship between TPN and complication and mor tality rates in critically ill patients. Data Sources.-Computerized search of published research on MEDLINE from 198 0 to 1998, personal files, and review of relevant reference lists. Study Selection.-We reviewed 210 titles, abstracts, and papers. Primary stu dies were included if they were randomized clinical trials of critically il l or surgical patients that evaluated the effect of TPN (compared with stan dard care) on complication and mortality rates. We excluded studies compari ng TPN with enteral nutrition. Data Extraction.-Relevant data were abstracted on the methodology and outco mes of primary studies. Data were abstracted in duplicate, independently. Data Synthesis.-There were 26 randomized trials of 2211 patients comparing the use of TPN with standard care (usual oral diet plus intravenous dextros e) in surgical and critically ill patients. When the results of these trial s were aggregated, TPN had no effect on mortality (risk ratio [RR], 1.03; 9 5% confidence interval [CI], 0.81-1.31). Patients who received TPN tended t o have a lower complication rate, but this result was not statistically sig nificant (RR, 0.84; 95% CI, 0.64-1.09), We examined several a priori hypoth eses and found that studies including only malnourished patients were assoc iated with lower complication rates but no difference in mortality when com pared with studies of nonmalnourished patients, Studies published since 198 9 and studies with a higher methods score showed no treatment effect, while studies published in 1988 or before and studies with a lower methods score demonstrated a significant treatment effect. Complication rates were lower in studies that did not use lipids; however, there was no difference in mo rtality rates between studies that did not use lipids and those studies tha t did, Studies limited to critically ill patients demonstrated a significan t increase in complication and mortality rates compared with studies of sur gical patients. Conclusions.-Total parenteral nutrition does not influence the overall mort ality rate of surgical or critically ill patients. It may reduce the compli cation rate, especially in malnourished patients, but study results are inf luenced by patient population, use of lipids, methodological quality, and y ear of publication.