Braden Score as an Alternative to the NNIS Risk Index in Orthopaedic Surgery

Background: The NNIS risk index is appropriate for comparison of data for most procedures and superior to the use of no risk adjustment. However, for some procedures, studies of alternative risk indexes are needed to better stratify patients. The Braden Score has been used in hospitals as a predictor of a patient developing a pressure sore so that those judged to be at risk can receive preventive care. This tool systematically evaluates patient risk for pressure sore development based on six categories: sensory perception, moisture, activity, mobility, nutrition and friction and shear. In Northern Ireland surgical site infection (SSI) surveillance is performed on all orthopaedic procedures. Objective: We decided to stratify orthopaedic procedures using the Braden Score and compare both the numbers and SSI rates stratified by NNIS-risk index.^1,2 Methods: SSI surveillance commenced in Northern Ireland in 2003. Data was collected by clinical staff with support and co-ordination provided by infection prevention and control teams. SSIs were detected during initial hospital stay and on readmission. We incorporated the 6 elements of the Braden Score into the routine surveillance of orthopaedic surgery. They were recorded on the day of surgery. Each element scores from 1 to 4, with the exception of friction and shear, which is scored from 1 to 3. The final score—obtained by totalling the scores from the six subscales—ranges from 6 to 23. Scores were grouped: 17-23 = no risk, 15-16 = low risk, 13-14 = moderate risk, 12 or less = high risk. Results: There were 194 SSIs recorded in 8099 orthopaedic procedures between September 2001 and July 2009. Table indicates the proportion of patients undergoing orthopaedic procedures by risk index and the proportion of patients within the Braden Score groups, also shown are SSI rates by risk index category and SSI rates by Braden Score groups. Table: Risk index, Braden score and SSI rate in 8099 orthopaedic procedures

	No. of patients	% of patients	SSI rate
NNIS Risk index
0	4372	54.0	1.67
1	3507	43.3	3.02
2	210	2.6	6.19
3	10	0.1	20.00
Braden Score group
No risk (17 – 23)	4461	55.1	0.41
Low risk (15 – 16)	1697	21.0	1.03
Moderate risk (13 – 14)	1295	16.0	1.48
High risk (12 or less)	646	8.0	3.45

Conclusions: Most patients undergoing orthopaedic procedures had a NNIS risk index spread across categories 0 and 1. In contrast, the same patients were spread across all categories of the Braden Score. The Braden Score may be used as an altenative to the NNIS risk index in orthopaedics. In addition, elements of the Braden Score are potentially modifiable. By identifying high-risk patients it may be possible to effectively plan, implement, and monitor a preventive programme for SSIs.

1. Bergstrom N, Braden B, et al. Using a research-based assessment scale in clinical practice. Nurs Clin N Am. 1995; 30 (3): 539-551.

2. Culver et al. Surgical wound infection rates by wound class, operative procedure and patient risk index. Am J Med 1991; 91(Suppl B): 3B -152S-157S.