The effect of caffeine on postoperative urinary retention after joint replacement surgery

Review of data on complications following joint replacement surgery revealed that urinary retention is a potential cause of increased morbidity. Repeat catheterizations, urinary tract infections, and possible infection of the prosthetic joint can result in a prolonged hospital length of stay. This study examined the effect of warm caffeinated coffee on a patient's ability to spontaneously void after indwelling catheter removal and the correlation between bladder volume and the ability to void spontaneously.

This was a randomized, controlled, pilot study of subjects who underwent unilateral total knee arthroplasty or total hip arthroplasty. The indwelling catheter was removed postoperative day 1. If unable to void within 3 hours, participants were randomized into a control group and an intervention group. At scheduled intervals, the control group consumed 8 oz of warm water and the intervention group consumed 8 oz of caffeinated coffee.

Thirty subjects were randomized; 14 were randomized to the water group and 16 to the caffeine group. Twenty-four subjects spontaneously voided after ingestion of fluid and six required straight catheterization. Of these six, five of the subjects had ingested water and one subject had ingested coffee. For those who spontaneously voided, there was not a significant difference between the caffeine group and the water group. There was a significant difference between caffeine ingestion and the volume of the void.

Findings from this study suggest that ingestion of caffeine after removal of an indwelling urinary catheter in the postoperative patient may increase the amount of voiding volumes initially, therefore avoiding the need for straight catheterization. To accurately assess this, extending the study into postoperative day 2 would allow us to evaluate whether lower voiding volumes lead to the need for catheterization.