Figure 4: A composite graph of urine flow and volume with NIRS parameters in a 72-year-old man with obstructive lower urinary tract symptoms. He had a trabeculated bladder on cystoscopic exam and increased bladder wall thickness on ultrasound. Following permission to void (P) total hemoglobin (tHb) falls; there is a drop in oxygenated hemoglobin (O2Hb) associated with a rise beginning in deoxygenated hemoglobin (HHb). Following uroflow start (S), this rising (positive) trend in HHb continues while O2Hb and tHb continue to fall until urine flow is decreasing. This implies an imbalance in oxygen supply and demand, which begins on initiation of voiding and continues beyond Qmax.