Duration of fluid fasting and choice of analgesic are modifiable factors for early postoperative delirium

A Special Authors Introduction

By Radtke et al

Postoperative delirium is a confusional state with alterations in attention and consciousness. It is a frequent and sometimes life threatening complication after surgical procedures and its prevalence is underestimated and its diagnosis is often missed. Besides an increase in health care costs, delirium also presents a psychological burden to the patient and its family.

Although the pathophysiology of delirium is not well understood, the concept of predisposing and precipitating factors introduced by Inouye and Charpentier is now widely accepted. The course of delirium can be influenced by the resolution of causative factors, though they are unclear or may not be easily identifiable. Therefore most therapeutic options for postoperative delirium are only symptom oriented; and the best approach remains prevention. However, in studies so far, pharmacological prophylaxis was not able to prevent the occurrence of delirium.

The task of the anaesthesiologist as the patient's advocate in the perioperative period is to prevent the occurrence of any avoidable harm. The Hippocratic Corpus already stated: "The physician must...have two special objects in view with regard to disease, namely, to do good or to do no harm" which may be shortened to: primum non nocere. Several data suggest that for example pain is a precipitating factor for delirium as are also potentially other surgical stressors.

In this observational, cohort study over 1000 patients undergoing surgery were screened for delirium in the postoperative anaesthesia care unit and on the first postoperative day on the ward using the Nursing Delirium Screening Scale. Besides known risk factors like age and site of surgery, potentially modifiable risk factors such as the duration of preoperative fluid fasting and intraoperative analgesia were identified in a multivariate analysis. Dehydration has been linked to impaired cognitive performance before, while more stable - not alpine - analgesia was able to influence the inflammatory response in other studies.

The authors conclude that changes in current practice designed to modify certain precipitating factors, such as better adherence to the fasting guideline may result in the prevention of delirium in a significant proportion of cases.

This article was published in European Journal of Anaesthesiology
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