Figure 3: A composite graph of UDS and NIRS parameters in a 64-year-old man with LUTS associated with BOO. Following permission to void (P), an increase in total hemoglobin (tHb) occurs due to a rise in oxygenated hemoglobin (O2Hb). Following uroflow start (S), a marked decrease in O2Hb occurs reflected by a comparable fall in tHb; this trend is evident up to Qmax, and towards the end of voiding O2Hb rises with a corresponding increase in tHb. This implies a decrease in the provision of oxygenated blood to the detrusor during the first two thirds of the voiding cycle.