The presence of certain risk factors can help identify a surgical patient who is more likely to have a retained sponge or instrument after surgery. A patient with one or more of these risk factors should be more closely monitored for signs that may be due to a retained surgical item. The authors are from Brigham and Women's Hospital and the Harvard School of Public Health.

Risk factors:

(1) operation performed as an emergency procedure

(2) unexpected change in the operation

(3) high body mass index (BMI)


Additional factors:

(4) failure to count sponges and instruments



Risk Ratio

95% CI

p Value

emergency surgery


2.4 – 31.9

< 0.001

unexpected change


1.4 – 12.4


high BMI (obesity)

1.1 per unit increment

1.0 – 1.2


counts performed


0.03 – 13.9


from Table 3, page 234



• Doing a count of sponges and instruments did not prevent errors, but failure to do a count was associated with errors. According to Table 2, almost half of the cases with retained items had a count performed that was considered correct (30 out 54).

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