Balanced crystalloids vs 0.9% saline for adult patients undergoing non-renal surgery: A meta-analysis

Fluid maintenance and resuscitation is an important strategy during major surgeries. There has been a debate on the choice of crystalloids over the past decades. 0.9% saline (normal saline) is more likely to cause hyperchloremic acidosis when compared to balanced crystalloids with low chloride content. Meta-analyses comparing these two kinds of crystalloids have been performed in renal transplantations. We aim to compare the safety of balanced crystalloids to normal saline among adult patients undergoing non-renal surgery.

Relevant articles were searched through PubMed, Embase and the Cochrane Library. Nine randomized controlled trials (including 871 participants) comparing balanced crystalloids to normal saline on adult patients undergoing non-renal surgery were finally included. Possible effects were calculated using meta-analysis.

Patients in the normal saline group had significantly lower postoperative pH (MD: 0.05; 95% CI: 0.04-0.06; p < .001; I² = 82%) and base excess (MD: 2.04; 95% CI: 1.44-2.65; p < .001; I² = 87%). The postoperative serum chloride level was significantly higher in the normal saline group (MD: -4.79; 95% CI: -8.13∼-1.45; p = .005; I² = 95%).

Comparing to normal saline, balanced crystalloids are more beneficial in keeping postoperative electrolytes and acid-base balance among adult patients undergoing non-renal surgery. Future researches should pay more attention to meaningful clinical outcomes concerning the safety of balanced crystalloids and normal saline.