Comparing different studies is difficult

Editorial by Offringa and Paper p 235

EDITOR—The debate over giving crystalloids or colloids has been raging since the 19th century, when Cohnheim and Lichtheim found gastric mucosal oedema in patients who had been resuscitated with saline and Starling suggested that albumin could prevent oedema. 12The meta-analysis by Schierhout and Roberts, which does not support the continued use of colloids for volume replacement in critically ill patients, makes a useful contribution to this debate but does not settle it.3

A recent review by Hankeln and Beez comes to the opposite conclusion—that colloids are more effective than crystalloids for optimising physiological variables related to flow in critically ill patients and maintaining the delivery of oxygen to the tissues2; they say that this is related to the persistence of colloids in the circulating plasma volume, as opposed to their distribution throughout the total body water.4Although colloids are more expensive than crystalloids, their effect on the circulating volume lasts much longer. The real problem is the difficulty in comparing different studies, because of differences in case mix, resuscitation protocols, and volumes and types of fluids used and, therefore, in making firm conclusions about patient outcome.

In all cases of hypovolaemia the main priority is to restore the circulatory volume as quickly and efficiently as possible to prevent impairment of organs due to ischaemia and hypoxaemia.5 Maybe we will never have a definitive answer to this question, in which case many practitioners will continue to administer a judicious mix of both types of fluid according to their own experience.

Newer synthetic colloids should not be abandoned

EDITOR—In their meta-analysis of trials that compared colloids with crystalloids in critically ill patients Schierhout and Roberts found increased mortality in patients treated with colloids and concluded: “this systematic review does not support the continued use of …