Perioperative nutrition is still a surgical orphan: results of a Swiss-Austrian survey.

Background/Objectives:There is strong evidence for the beneficial effects of perioperative nutrition in patients undergoing major surgery. We aimed to evaluate implementation of current guidelines in Switzerland and Austria.Subjects/Methods:A survey was conducted in 173 Swiss and Austrian surgical departments. We inquired about nutritional screening, perioperative nutrition and estimated clinical significance.Results:The overall response rate was 55%, having 69% (54/78) responders in Switzerland and 44% (42/95) in Austria. Most centres were aware of reduced complications (80%) and shorter hospital stay (59%). However, only 20% of them implemented routine nutritional screening. Non-compliance was because of financial (49%) and logistic restrictions (33%). Screening was mainly performed in the outpatient's clinic (52%) or during admission (54%). The nutritional risk score was applied by 14% only; instead, various clinical (78%) and laboratory parameters (56%) were used. Indication for perioperative nutrition was based on preoperative screening in 49%. Although 23% used preoperative nutrition, 68% applied nutritional support pre- and postoperatively. Preoperative nutritional treatment ranged from 3 days (33%), to 5 (31%) and even 7 days (20%).Conclusions:Although malnutrition is a well-recognised risk factor for poor post-operative outcome, surgeons remain reluctant to implement routine screening and nutritional support according to evidence-based guidelines.

Perioperative nutrition is still a surgical orphan

Objective: To assess if screening programs and treatment of preoperative malnutrition have been implemented into surgical practice to decrease morbidity. There is strong evidence that postoperative morbidity can be minimized by early identifying and treating patients at nutritional risk before major surgery.The validated nutritional risk score (NRS) is recommended by the European Society of Parenteral and Enteral Nutrition for nutritional screening. It remains unclear whether routine preoperative nutritional assessment and perioperative nutrition is widely implemented.Methods: A survey was conducted in 173 Swiss and Austrian surgical departments. Implementation of nutritional screening, perioperative nutrition, and estimated impact on clinical outcome were assessed. Non-responders were repeatedly contacted by the authors.Results: The overall response rate was 55%, whereby 69% (54/78) of Swiss and 44% (42/95) of Austrian centers responded. Despite 80% and 59% of the responding centers are aware of a reduced complication rate and shortened hospital stay, respectively, only 20% of them implemented routine nutritional screening. Financial (49%) and logistic restrictions (33%) are the predominant reasons against the routine clinical use. Screening is mainly performed either in the outpatient's clinic (52%) or during admission (54%). The NRS is only used by 14%. Instead, various clinical (78%), e.g. BMI and laboratory findings (56%), e.g. albumine, are used. Indication for perioperative nutrition is based on preoperative screening in 49%.While 23% use preoperative nutrition, 68% apply nutritional support pre- and postoperatively. Preoperative nutritional treatment ranged from three days (33%), to five days (31%) and even seven days (20%).Conclusion: Despite malnutrition is well recognized as major risk factor for increased postoperative morbidity, the majority of surgeons are reluctant to implement routine screening and nutritional support. If nutritional assessment is performed, local institutional screening parameters are still preferred. It remains difficult to overcome traditions, and to change surgeon's mind.

Problems of allometric scaling analysis: examples from mammalian reproductive biology.

Biological scaling analyses employing the widely used bivariate allometric model are beset by at least four interacting problems: (1) choice of an appropriate best-fit line with due attention to the influence of outliers; (2) objective recognition of divergent subsets in the data (allometric grades); (3) potential restrictions on statistical independence resulting from phylogenetic inertia; and (4) the need for extreme caution in inferring causation from correlation. A new non-parametric line-fitting technique has been developed that eliminates requirements for normality of distribution, greatly reduces the influence of outliers and permits objective recognition of grade shifts in substantial datasets. This technique is applied in scaling analyses of mammalian gestation periods and of neonatal body mass in primates. These analyses feed into a re-examination, conducted with partial correlation analysis, of the maternal energy hypothesis relating to mammalian brain evolution, which suggests links between body size and brain size in neonates and adults, gestation period and basal metabolic rate. Much has been made of the potential problem of phylogenetic inertia as a confounding factor in scaling analyses. However, this problem may be less severe than suspected earlier because nested analyses of variance conducted on residual variation (rather than on raw values) reveals that there is considerable variance at low taxonomic levels. In fact, limited divergence in body size between closely related species is one of the prime examples of phylogenetic inertia. One common approach to eliminating perceived problems of phylogenetic inertia in allometric analyses has been calculation of 'independent contrast values'. It is demonstrated that the reasoning behind this approach is flawed in several ways. Calculation of contrast values for closely related species of similar body size is, in fact, highly questionable, particularly when there are major deviations from the best-fit line for the scaling relationship under scrutiny.