2,833 publications from this institution
3 and suggest an evidence-based algorithm, which essentially does not foresee supplemental parenteral nutrition (SPN) before days 5-7 after intensive care unit (ICU) admission, even in patients with contra-indication for enteral nutrition. 1 Furthermore, they state that SPN probably should be restricted to the most severely ill patients (possible long stayers), and in patients with malnutrition SPN
We collected all complete sets of measurements of cardiac index and oxygen-derived variables available in the recent literature (1975-1991; computerised Medline search) on critically ill patients with sepsis (n=21 studies), septic shock (n=20 studies) or severe heart failure (n=13 studies). For each study, the mean value for cardiac index, oxygen delivery (DO 2), oxygen uptake (VO 2), oxygen extraction ratio (O 2ER) and lactate concentration (when available) were analysed together with mortality rates. There was a significant relationship between VO 2 and DO 2 for the studies on patients with severe heart failure (r=0.79, p less than 0.001) or septic shock (r=0.55, p less than 0.01), but not in patients with sepsis (r=0.3, p=NS). As expected, O 2ER was higher in the studies in heart failure (31 to 50%) than in septic shock (25 to 45%) or sepsis (19 to 40%). When compared to the studies on patients with sepsis, the studies in septic shock included patients with lower DO 2 (481+/-89 vs 539+/-79 ml/min.M 2, p=0.032) and higher O 2ER (32.5+/-5.2 vs 27.8+/-5.0%, p less than 0.01) but similar VO 2 (143+/-29 vs 143+/-19 ml/min.M 2, p=NS). In a cardiac index/O 2ER diagram where a line of reference represents proportional changes in cardiac index and O 2ER from normal values at rest, all studies in heart failure fell below the line of reference. The majority of studies in sepsis (18/21) fell above the line of reference. Interestingly, only nine of the 20 studies in septic shock fell above this line. The review of the 14 studies in septic shock, in which O 2ER and blood lactate were reported, showed a direct relationship between these two variables (r=0.68, p less than 0.01), but no relationship between cardiac index and blood lactate (r=0.37, p=NS). This analysis suggests that patients with septic shock tend to have a lower cardiac index and higher O 2ER than septic patients who are haemodynamically stable. Furthermore, the positive relationship between O 2ER and lactate suggests that, despite the alterations in oxygen extraction capabilities in severe sepsis, mean O 2ER may be higher in the most severe cases of septic shock. This could reflect an attempt to maintain VO 2 when DO 2 is insufficient. The prevailing opinion that 0 2ER is a meaningless variable in septic shock needs to be reassessed.
info:eu-repo/semantics/published
The metabolic support of critically ill patients is a relatively new topic of active research and discussion, and surprisingly little is known about the effects of critical illness on metabolic physiology and activity. The metabolic changes seen in critical illness are highly complex, and how and when to treat them are only just beginning to be determined. Studies have demonstrated that the acute phase and the later phase of critical illness behave differently from a metabolic point of view for many organs, and while many of the alterations in metabolism seen during early critical illness may be appropriate and beneficial responses to cellular stress, whether this is true for all the metabolic alterations in all forms of critical illness is unclear. Currently we face more questions than answers, and further study is needed to elucidate the various components of the metabolic response to acute and chronic critical illness and to develop better techniques to assess and monitor these changes so that we can determine which therapeutic approaches should be used in what combinations and in which patients.
