Interventions for protecting renal function in the perioperative period.
BACKGROUND
A number of methods have been used to try to protect kidney function in patients undergoing surgery. These include the administration of dopamine, diuretics, calcium channel blockers, angiotensin converting enzyme inhibitors and hydration fluids.


OBJECTIVE
For this review, we selected randomized controlled trials, which employed different methods to protect renal function during the perioperative period. In examining these trials, we looked at outcomes such as renal failure and mortality, as well as changes in the renal function tests, including urine output, creatinine clearance, free water clearance, fractional excretion of sodium and renal plasma flow.


METHODS
We searched the Cochrane Central register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2004), MEDLINE (1966 to 2004) and EMBASE (1988 to 2004) and hand searched six journals (British Journal of Anaesthesia; Anesthesia and Analgesia; Anesthesiology; Annals of Surgery; Journal of Thoracic and Cardiovascular Surgery and Journal of Vascular Surgery).


METHODS
We selected all randomized controlled trials in adult population undergoing surgery where a treatment measure was used for the purpose of renal protection in the perioperative period.


METHODS
We selected 37 studies for inclusion in this review. As well as analysis of the data from all the studies, we also performed subgroup analysis for type of interventions, types of surgical procedures and those with pre-existing renal dysfunction. We undertook sensitivity analysis on studies with high methodological quality.


RESULTS
The review included data from 37 studies, comprising a total of 1227 patients. Of these, 658 received some form of treatment and 569 acted as controls. The interventions were mostly employing different pharmaceutical agents such as dopamine, diuretics, calcium channel blockers. ACE inhibitors or selected hydration fluids. The results indicated that certain interventions showed some benefits, but all the results suffered from significant heterogeneity. Hence we can draw no conclusions about the effectiveness of these interventions in protecting the kidneys during surgery.


CONCLUSIONS
There is no reliable evidence from available literature to suggest that interventions during surgery can protect the kidneys from damage. However, there is a need for more studies of high methodological quality. One particular area for further studies may be on patients with pre-existing renal dysfunction undergoing surgery.
Zacharias
M
M
Anaesthesia & Intensive Care, Dunedin Hospital, Great King Street, Dunedin, Otago, New Zealand. mathew.zacharias@stonebow.otago.ac.nz
Gilmore
I C S
IC
Herbison
G P
GP
Sivalingam
P
P
Walker
R J
RJ
D003404:Creatinine / Q000652:urine; D006801:Humans; D011183:Postoperative Complications / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D051437:Renal Insufficiency / Q000517:prevention & control*; D013514:Surgical Procedures, Operative / Q000009:adverse effects*; D014556:Urine
D003404:Creatinine