Measurement of energy expenditure in acute stage of cerebrovascular diseases

Daily systemic energy expenditure in the acute phase of aneurysmal subarachnoid hemorrhage

Background: Patients with subarachnoid hemorrhage often have impaired consciousness and cannot regulate nutritional intakes themselves. Previous studies have demonstrated elevated energy expenditure in the acute phase, but it is not known whether the energy demand is constant during the first week after onset of the disease. In this study, we performed daily measurements of energy expenditure with indirect calorimetry during the first 7 days after aneurysmal subarachnoid hemorrhage in mechanically ventilated patients.Methods: Metabolic measurements were performed daily with indirect calorimetry in 26 patients with aneurysmal subarachnoid hemorrhage. All patients were intubated and mechanically ventilated. The measured value was compared to the predicted values from the Harris-Benedict equation and the Penn State University 1998 equation. Urinary nitrogen excretion was measured daily.Results: There was a significant increase in energy expenditure during days 2-3 compared to days 5-6. The Harris-Benedict equation underestimated metabolic demand. The Penn State 1998 equation was closer to the measured values, but still underestimated caloric need. Urinary nitrogen excretion increased throughout the first week from initially low values.Conclusions: There is a dynamic course in energy expenditure in patients with aneurysmal subarachnoid hemorrhage, with increasing metabolic demand during the first week of the disease. Indirect calorimetry could be used more often to help provide an adequate amount of energy.

Increased Resting Energy Expenditure after Endovascular Coiling for Subarachnoid Hemorrhage

BACKGROUND

Appropriate nutritional care from the acute stage is essential for improved functional outcomes and reduced mortality in patients with subarachnoid hemorrhage (SAH). Although endovascular coiling is increasingly being used as an alternative to neurosurgical clipping and craniotomy for ruptured aneurysms, the resting energy expenditure (REE) of patients treated with this new technique has not been systemically evaluated.

METHODS

We measured REE values by indirect calorimetry in 12 SAH patients treated with endovascular coiling. We averaged the REE measurements obtained on days 1 and 7 after endovascular coiling, and then we statistically compared the mean REE values with those in 30 patients with acute cerebral infarction (ACI) by the Wilcoxon rank-sum test (P <.05). Next, we calculated the ratio of measured REE values to the values estimated using the Harris-Benedict equation to adjust for demographic differences in sex, weight, height, and age between the groups.

RESULTS

The ratios were significantly higher in SAH patients (median value, 1.12; interquartile range, 1.05-1.23) than in ACI patients (median value, 1.02; interquartile range, .97-1.09).

CONCLUSIONS

Because endovascular coiling is less invasive than neurosurgical clipping, the observed increase in REE was attributed to metabolic changes after SAH. To provide optimal nutritional care to SAH patients from the acute stage, clinicians should be aware of this change in REE.

End-tidal carbon dioxide as a measure of stress response to clustered nursing interventions in neurologic patients

BACKGROUND

Guidelines recommend rest periods between nursing interventions for patients with a neurologic diagnosis but do not specify a safe number of interventions.

OBJECTIVES

To examine the physiological stress response to clustered nursing interventions in neurologic patients receiving mechanical ventilation.

METHODS

Prospective, comparative, descriptive design to examine effects of clustered interventions (≥6 interventions in a single nursing interaction) versus nonclustered interventions on patients' stress. Stress response was defined as a 10% change in end-tidal carbon dioxide from before the interaction to (1) 5 and 10 minutes after the start of the interaction, (2) at the end of the interaction, and (3) 15 minutes after the interaction.

RESULTS

The mean percent change in end-tidal carbon dioxide at 5 minutes differed significantly between patients with clustered interventions and patients with nonclustered interventions (6.7% vs -0.2%; P = .001). Patients with clustered interventions were significantly more likely than patients with low clustering to exhibit a stress response at 5 minutes (24.3% vs 0%; P = .01).

CONCLUSIONS

Neurologic patients receiving mechanical ventilation who experienced 6 or more clustered nursing interventions showed a higher mean change in end-tidal carbon dioxide than did patients who received fewer than 6 clustered interventions. These findings suggest that providing fewer interventions during 1 nursing interaction may minimize induced stress in neurologic patients receiving mechanical ventilation.

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.