To the Editor:—

While intraoperative oliguria in not a reliable predictor of postoperative renal dysfunction, vigilant effort is made by the anesthesiologist to keep the patient's urine output at an acceptable level. The total absence of urine in the collection bag suggests either a mechanical obstruction or extreme renal hypoperfusion and subsequent lack of glomerular filtration. We describe an “epidemic” of intraoperative anuria due to defective Foley catheters.

A 45-yr-old patient presented for sigmoid colectomy. Prior to the abdominal incision, the operating room nurse placed a Foley catheter (Foley tray; Bard Medical, Covington, GA). Three hours later, the patient was anuric despite receiving 3 l of lactated Ringer's solution. The surgeon examined the exposed bladder and reported that it was “empty.” Furosemide, 5 mg intravenously, was given in an unsuccessful attempt to promote a diuresis. After completion of surgery, we attempted to irrigate the Foley catheter but without success. The catheter was replaced, resulting in the brisk return of copious urine.Examination of the original Foley catheter revealed a manufacturer's defect: absence of the end hole (fig. 1).

Fig. 1. Two Foley catheters: the top catheter is normal, and the lower catheter is defective, with lack of an orifice.

Fig. 1. Two Foley catheters: the top catheter is normal, and the lower catheter is defective, with lack of an orifice.

An 85-yr-old woman underwent coronary artery bypass surgery with aortic valve replacement. A Foley catheter was placed (CRITICORE Foley tray; Bard Medical) following induction of anesthesia. The lack of urine draining into the catheter prompted a call to the urology service. After establishing correct placement (transabdominal palpation of inflation and deflation of the Foley catheter balloon), irrigation was attempted without success. The catheter was then replaced. The replaced Foley catheter was examined and found to be lacking an orifice (same defect as depicted in fig. 1).

While intraoperative oliguria is indicative of renal hypoperfusion, anuria suggests the possibility of either catheter occlusion or the detachment of the tubing from the collection bag. Irrigation of the Foley catheter always should be the first step in the evaluation of the anuric patient. In these two cases, it was not possible to irrigate the bladder due to a lack of communication between the catheter lumen and the patient's bladder. As the first patient voided immediately prior to his arrival in the operating room, the initial lack of return of urine into the Foley collection bag, even with suprapubic compression, was not surprising. Since anesthesiologists rely on urine output as an indicator of renal perfusion, confirming proper placement and function of the catheter by demonstrating the flow of urine should be a routine procedure prior to the beginning of surgery.