We recently developed continuous negative pressure therapy with irrigation (NPI) and successfully applied it to an infected digit with a narrow wound. With this technique, however, the dressing circumferentially wraps the digit or hand, and the pressure that the digit or hand receives and the influence on peripheral circulation are unclear. In this report, we evaluated the external pressure that a digit and hand received during NPI in vitro. Under circumferential NPI dressing, the skin perfusion pressure (SPP) of the peripheral portion was measured. Pressure was maintained at 1.3 mm Hg, and suction pressure ranged from -50 to -200 mm Hg. The pressure that a digit or hand receives during NPI is much lower than that at which tissue may be damaged (40-50 mm Hg). The SPP of the peripheral portion was much higher than 40 mm Hg, which is the pressure at which wound healing may be predicted. In clinical cases, NPI has been useful for wound bed preparation.