Fasting guidelines in different countries

Insulin resistance: a marker of surgical stress

Elective surgery causes a marked, transient reduction in insulin sensitivity. The degree of the reduction is related to the magnitude of the operation. The type and duration of surgery performed, perioperative blood loss, and also the degree of postoperative insulin resistance have significant influences on the length of hospital stay. A novel approach to minimize insulin resistance after surgery is being presented and suggests that simply pretreating the elective surgical patient with sufficient amounts of carbohydrates instead of fasting can significantly reduce postoperative insulin resistance. It is not clear which mediators are the most important for the development of insulin resistance after surgery. Nevertheless, marked insulin resistance can develop after elective surgery without concomitant elevations in cortisol, catecholamines or glucagon. The main sites for insulin resistance seem to be extrahepatic tissues, probably skeletal muscle, where preliminary data suggest that the glucose transporting system is involved.

Changing preoperative fasting policies. Impact of a national consensus

BACKGROUND

Liberalisation of preoperative fasting rules has been discussed and recommended in the anaesthesia literature in recent years. In Norway, a national consensus on this issue was reached in 1993. The aim of the present study was to investigate whether a national consensus on fasting recommendations led to a change in fasting policies in Norwegian anaesthesia departments.

METHODS

A questionnaire on preoperative fasting routines was sent to all Norwegian anaesthesia departments in 1993 and repeated in 1996.

RESULTS

Written local guidelines for preoperative fasting were present in 85% of the institutions in both surveys. Of the hospitals, 69% had changed their local guidelines after the national consensus. In 1996 more hospitals allowed less than 6 h fasting for clear liquids in children (93% versus 71% in 1993; P < 0.005). A similar tendency was noted in adults (79% versus 63% in 1993; P = 0.1). In contradiction to the national guidelines, 31% of the departments reported that they allowed less than 6 h fasting after a light breakfast in the morning of surgery in 1996. The corresponding number for 1993 was 21% (ns).

CONCLUSION

The new, consensus-based national fasting guidelines have been associated with a change towards more liberal fasting policies in Norwegian departments of anaesthesia. However, as not all local changes were supported by the national consensus, other sources of information were used when local policies were decided.

Perioperative oral nutrition

Much attention has been paid to perioperative intravenous nutrition and postoperative enteral nutrition but the literature concerning perioperative oral nutrition is sparse. This review will draw attention to new ideas about preoperative feeding instead of overnight fasting, it will show that immediate postoperative oral nutrition is tolerated in significant amounts, that liquid supplements may be given routinely after elective surgery, and that it is worth giving dietary advice to malnourished patients on discharge from hospital.