Preparation, premedication, and surveillance

The endoscopic literature published during the past year has once again con firmed that there is significant variation from country to country regardin g whether or not patients wish to receive conscious sedation during endosco py (and particularly colonoscopy) - and there may even be variation from on e endoscopic unit to another within the same country Particular attention h as been given to attempts to identify "ideal" candidates for conscious seda tion, and to the importance of providing patients with information before t he procedure. It has been shown that patients who receive detailed informat ion about a medical procedure beforehand are able to benefit from this. The role of benzodiazepines, particularly midazolam, was investigated in studi es emphasizing that the dosage should be kept to the minimum that is compat ible with patient comfort and successful performance of the procedure. Ther e have been few publications comparing propofol with midazolam. As expected , in view of the known pharmacological properties of the two drugs, the qua lity of sedation was better and the recovery time was shorter in patients w ho were treated with propofol. However, important questions are still open regarding the narrow therapeutic range of propofol and the methods by which it is administered (by endoscopists or by anesthesiologists). An important aspect of sedation procedures is the prevention of hypoxia and cardiopulmo nary complications. Recent endoscopic reports have added little further inf ormation concerning the well-known risk of oxygen desaturation during consc ious sedation. Performing endoscopy in unsedated patients reduces, but does not eliminate, the risk of hypoxia. Among the various risk factors, it has been found that chronic respiratory failure and coronary heart disease are factors predictive of severe desaturation and relevant electrocardiographi c changes. The use of electronic monitoring techniques with pulse oximetry is recommended as a standard procedure during digestive endoscopy; however, it has been observed that when supplemental oxygen is administered, pulse oximetry no longer reflects normal ventilatory function and does not detect episodes of severe CO2 retention. Transcutaneous measurement of PCO2 there fore seems more reliable as a means of assessing hypoventilation. Several p apers have proposed "ideal formulas" for bowel preparation for endoscopic p rocedures. Various regimens have been proposed as alternatives to polyethyl ene glycol electrolyte lavage solution (PEG-ELS) and sodium phosphate compo unds, with different results. On the whole, there is still little informati on regarding the best and most cost-effective method of bowel cleansing for colonoscopy and flexible sigmoidoscopy.