Computerized energy balance and complications in critically ill patients: an observational study

Early nutrition support in critical care: a European perspective

PURPOSE OF REVIEW

Today, early nutrition support is considered standard care in most ICUs. The recommended method is the enteral route, although there is only minor evidence for this. Often inadequate delivery of energy and a cumulative energy deficit are implied. The purpose of this paper is to evaluate the indication for early enteral nutrition or immunonutrition and to discuss the application of additional parenteral nutrition.

RECENT FINDINGS

The indication for early enteral nutrition is also supported by guidelines for enteral nutrition recently published by the European Society for Clinical Nutrition and Metabolism. Some more recent results strengthen the indication for a special formula in acute respiratory distress syndrome and septic patients. A recent metaanalysis has shown that parenteral nutrition is superior to delayed enteral nutrition. Additional parenteral nutrition thus seems to be the way to avoid cumulative energy deficit associated with insufficient or no enteral nutrition.

SUMMARY

Early enteral nutrition is recommended for critically ill patients, with special formulas indicated in specific subgroups of patients. If enteral nutrition is insufficient or fails, parenteral nutrition should be instituted, respecting the often reduced demand for exogenous substrates in critically ill patients.

The effects of sedation on gastric emptying and intra-gastric meal distribution in critical illness

OBJECTIVE

To evaluate the effects of sedation with morphine and midazolam (M&M) versus propofol on gastric emptying in critically ill patients.

DESIGN

Descriptive study.

SETTING

Mixed medical and surgical intensive care unit.

PATIENTS

Thirty-six unselected, mechanically ventilated, critically ill patients.

INTERVENTIONS

Gastric scintigraphic data were analysed retrospectively according to whether patients were receiving M&M (n=20; 14M, 6F) or propofol (n=16; 7M, 9F). Measurements were performed over 4 h after administration of 100 ml of Ensure, labelled with 20 MBq Tc99m.

MEASUREMENTS AND RESULTS

Gastric half-emptying time (t1/2) and total and regional (proximal and distal stomach) meal retention (%) were assessed. The median t1/2 of patients receiving M&M (153 (IQR: 72-434) min) was significantly longer than that of patients receiving propofol (58 (34-166) min, p=0.02). Total gastric retention was greater in patients receiving M&M compared to those receiving propofol (p<0.01). Proximal (p=0.02) but not distal (p=0.80) gastric retention was greater in patients who received M&M. Patients who received M&M were more likely to have >or=5% meal retention at 240 min than those treated with propofol (95% (19/20) vs. 56% (9/16); p=0.01). Changes in blood glucose concentrations during the study were similar in the two groups.

CONCLUSIONS

In critical illness, patients receiving M&M for sedation are more likely to have slow gastric emptying, and proximal meal retention than those receiving propofol. The apparent beneficial effects of propofol-based sedation need confirmation by a prospective randomised controlled study.

Controversies in the determination of energy requirements

To avoid any negative outcomes associated with under- or overfeeding it is essential to estimate nutrient requirements before commencing nutrition support. The energy requirements of an individual vary with current and past nutritional status, clinical condition, physical activity and the goals and likely duration of treatment. The evidence-base for prediction methods in current use, however, is poor and the equations are thus open to misinterpretation. In addition, most methods require an accurate measurement of current weight, which is problematic in some clinical situations. The estimation of energy requirements is so challenging in some conditions, e.g. critical illness, obesity and liver disease, that it is recommended that expenditure be measured on an individual basis by indirect calorimetry. Not only is this technique relatively expensive, but in the clinical setting there are several obstacles that may complicate, and thus affect the accuracy of, any such measurements. A review of relevant disease-specific literature may assist in the determination of energy requirements for some patient groups, but the energy requirements for a number of clinical conditions have yet to be established. Regardless of the method used, estimated energy requirements should be interpreted with care and only used as a starting point. Practitioners should regularly review the patient and reassess requirements to take account of any major changes in clinical condition, nutritional status, activity level and goals of treatment. There is a need for large randomised controlled trials that compare the effects of different levels of feeding on clinical outcomes in different disease states and care settings.

Hypocaloric feeding: pros and cons

PURPOSE OF REVIEW

Since the 1980s, hypocaloric feeding has been regularly proposed in the critically ill, although there is no clear definition available, nor evidence-based strategy to support it. We aim to define hypocaloric feeding based on indirect calorimetric data and to discuss patient-relevant clinical outcomes resulting from hypocaloric feeding.

RECENT FINDINGS

Overfeeding and underfeeding both have proven deleterious effects and should be avoided, which requires determination of the patient's total energy requirement. Indirect calorimetry appears as the only precise method to determine such requirements in clinical settings. We define hypocaloric feeding as the delivery of 0.5-0.9 times the resting energy expenditure, isocaloric feeding as 1.1-1.3 times the resting energy expenditure, whereas hypercaloric feeding delivers more than 1.5 times the resting energy expenditure. Whether the patients are lean or obese, all the available predictive equations of energy requirements are grossly inaccurate in more than 30% of cases.

SUMMARY

There is growing evidence that negative energy balances are associated with poor intensive-care-unit and hospital outcome. Using an evidence-based approach, hypocaloric feeding in the critically ill cannot be supported either. Whether the cutoff of tolerance for introducing feeding is 24 h or more is not yet defined and still awaits a prospective trial.

Is it now time to promote mixed enteral and parenteral nutrition for the critically ill patient?

BACKGROUND

Intensive care outcome measured by morbidity and mortality is altered in the severely malnourished ICU patient, and nutritional support of the critically ill is accepted as a standard of care. Current recommendations suggest starting enteral feeding as soon as possible whenever the gastrointestinal tract is functioning. The disadvantage of enteral support is that inadequate energy and protein intake can occur. The present commentary focuses on some recent findings regarding the nutritional support of critically ill patients and proposes to promote mixed nutrition support by enteral nutrition (EN), and by parenteral nutrition (PN) whenever EN is insufficient.

RECENT FINDINGS

An increasing nutrition deficit during a long ICU stay is associated with increased morbidity (increased infection rate or impaired wound healing). Evidence shows that EN can result in underfeeding and that nutrition goals are reached only after 5-7 days. Contrary to former beliefs, recent meta-analyses of studies in the ICU showed that PN is not related to excess mortality but may even be associated with improved survival.

CONCLUSIONS

Optimising the increased substrate requirement for the critically ill by initiating timely nutrition support and ensuring tight glycaemic control with insulin is now considered central for improved intensive care outcomes. Supplemental PN combined with EN could be an effective alternative to achieve 100% of energy and protein targets at day 4, when EN alone fails to achieve goals greater than 60% by day 3. Whether such combined nutrition support provides additional benefit on overall outcome has to be ascertained in further studies.

Comparison of metabolic monitors in critically ill, ventilated patients

OBJECTIVE

We compared the Deltatrac II, the M-COVX, and the Evita 4 metabolic monitoring devices under clinical conditions.

METHODS

A prospective simultaneous clinical comparison was performed in a general intensive care department of a tertiary university hospital in 43 ventilated, critically ill patients. The monitors were compared simultaneously. After 30 min of steady state, oxygen consumption per unit time, carbon dioxide consumption per unit time, resting energy expenditure, and respiratory quotient were recorded for the Deltatrac II; the same parameters in addition to end-tidal carbon dioxide and fraction of inspired oxygen were recorded for the M-COVX; and carbon dioxide consumption per unit time, end-tidal carbon dioxide, and fraction of inspired oxygen were recorded for the Evita 4. Pulmonary gas-exchange measurements from the Deltatrac II and resting energy expenditure and respiratory quotient from the M-COVX were obtained after 30 min. The other parameters were calculated from the last five measurements obtained at the end of the study period.

RESULTS

A good correlation was found between oxygen consumption per unit time and resting energy expenditure as obtained from the Deltatrac II and the M-COVX (r = 0.76 and 0.75, respectively; P < 0.001), but the correlation was lower between carbon dioxide consumption per unit time as obtained from the Deltatrac II and the M-COVX or Evita 4 (r = 0.67 and 0.48, respectively). Agreement between the different methods did not reach clinical acceptability, exceeding a 20% difference using the Bland-Altman statistical methods.

CONCLUSION

Poor agreement was found between the Deltatrac II and M-COVX or Evita 4 metabolic monitors, despite a good correlation between measurements, leading to the conclusion that the M-COVX and Evita 4 provide less accurate measurements of metabolic gas exchange in stable ventilated patients. These devices can be used for daily nutritional assessment and continuous monitoring, but the Deltatrac II remains the method of choice for metabolic measurement.

[An immunohistochemical study of various breast tissues using CA15-3 (MAb 115D8 and MAb DF3)]

A CA15-3 RIA KIT, composed with two different monoclonal antibodies (115D 8 and DF 3), has been seen to react with the sera of breast cancer patients. Although the subclass of both antibodies is different, the antigen that reacted with them seems to be same, with a range from 300-450 kd. To reveal the reacting pattern of both antibodies, an immunohistochemical study was performed involving various breast tissues. In general, normal and benign breast tumors exhibited an apical stain by 115D8 and an apical and focal cytosol stain by DF 3. Breast carcinomas displayed not only an apical stain but a strong cytosol stain. However, the staining patterns showed little difference.