For years I have been trotting around the world telling everyone that NaCl 0.9% is evil, because each litre delivers 50mmol of HCL and chloride is nephrotoxic. This belief has come from a series of studies in volunteers (reduced GFR, reduced splanchnic perfusion, reduced cortical blood flow) and observations (increased contrast nephropathy with NaCl versus NaHCO3. I suggested that the CHEST trial failed to prove that HES was dangerous because the control fluid was saline. But where was the real proof of nephrotoxicity.
Here it is in JAMA (click here).
A group in Melbourne, Australia, performed a sequential patient cohort study during 2 time periods: in phase 1 any IV fluid could be used; in phase 2 (the following year), chloride rich fluids were unavailable, so balanced salt solutions only could be prescribed.
Chloride administration fell considerably: from 694 to 496 mmol/patient from the control period to the intervention period. Patients in the chloride rich period had significantly worse renal outcomes: the mean serum creatinine level increase while in the ICU was 22.6 μmol/L (95% CI, 17.5-27.7 μmol/L) vs 14.8 μmol/L (95% CI, 9.8-19.9 μmol/L) (P = .03), the incidence of injury and failure class of RIFLE-defined AKI was 14% (95% CI, 11%-16%; n = 105) vs 8.4% (95% CI, 6.4%-10%; n = 65) (P <.001), and the use of RRT was 10% (95% CI, 8.1%-12%; n = 78) vs 6.3% (95% CI, 4.6%-8.1%; n = 49) (P = .005). In other words – patients given balanced chloride fluids had a 3.7% reduction in the risk of needing dialysis (NNT <30). As you would expect, there was no difference in mortality figures.
The accompanying editorial can be read here.
Saline (in HES) also impairs platelet function more than balanced salt (in HES)- at least in some measures of platelet function. Another reason not to give saline.
British Journal of Anaesthesia 109 (4): 572–7 (2012)
Advance Access publication 11 July 2012 . doi:10.1093/bja/aes229