ENGAGING SURGEONS AND ANAESTHETISTS IN AKI: CAN ASA GRADE BE USED AS A PREDICTOR OF AKI?
Weerakkody S1, Hutchins D1, Taylor R1, Parry R2
Department of Anaesthesia1 and Department of Renal Medicine2, Royal Cornwall Hospital
BACKGROUND: Post operative Acute Kidney Injury (AKI) is associated with increased hospital and long term mortality.1 A significant proportion of these patients go on to develop chronic kidney disease and cardiovascular complications.2 Preoperative risk factors have been implicated with an increased risk of AKI.3,4 ASA (American Society of Anaesthesiologists) grade I-V is a reproducible perioperative risk stratification tool which is in common usage worldwide by both anaesthetists and surgeons. We assess if ASA grade could be used as a risk assessment tool to aid prediction of AKI.
METHODS: An audit of 100 consecutive patients having major abdominal surgery over a 6 month period (September 2010 and January 2011).
There were 107 patients: age range 16-89 years (mean 63); Sex: 29 female, 78 male.
25 (23.4%) patients developed AKI; AKI1 5 (4.7%), AKI2 11(10.3%), AKI3 9 (8.4%)
AKI and ASA grade:
AKI patients and Age group: Age<50 3/27 (11.1%), 51-60 0/4, 61-70 10/35 (28.5%), 71-80 7/28 (25%), >80 5/13 (38.4%)
AKI and MAP: Average MAP in the AKI group was 67mmHg compared to 82.7mmHg in the non-AKI group.
Type of surgery: Laparoscopic vs open: Of 107 patients 28 were laparoscopic (3 (10.7%) developed any stage AKI), 79 patients were open procedures ( 24 (30.4%) developed AKI).
Elective vs emergency: 58 cases were elective, of these 9 (15.5%) developed AKI; 45 cases were classed as emergency, of these 16 patients (32.7%) developed AKI.
Nephrotoxic drugs: 18 patients of 25 who developed any stage AKI, were prescribed regular nephrotoxic drugs.
ASA grade was strongly correlated with incidence of AKI (Spearman’s Rank correlation coefficient 83%).
A large proportion of general surgical patients developed AKI post operatively. A striking observation was the almost linear relationship observed between ASA grade and incidence of AKI.
Using ASA grade may be useful in helping to predict which patients may go onto develop AKI and has the advantage that it is common usage by both surgical and anaesthetic teams. Further work is required to ascertain if this relationship is reproducible in larger samples.
1. Ostermann et al. Critical Care 2008; 12:R144 2. Coca S et al. Am J Kidney D June 2009 Long-term Risk of Mortality and Other Adverse Outcomes After Acute Kidney Injury: A Systematic Review and Meta- analysist 3. Kheterpal et al Anaesthesiology March 2009 Acute Kidney Injury Risk Index for Patients Undergoing General Surgery SetVolume 110 - Issue 3 - pp 505-515 4.Acute Kidney Injury Network (AKIN) www.akinet.org/50>