ObjectiveTo evaluate the accuracy and reliability of noninvasive continuous finger blood pressure measurement in critically ill patients.DesignProspective data collection.SettingEmergency department in a 2,000-bed hospital.PatientsThirty-nine patients admitted to the emergency department requiring invasive arterial blood pressure monitoring were enrolled to the study protocol.InterventionsContinuous noninvasive blood pressure measurement was performed on the middle phalanx of the second and third finger, using a test instrument which provides continuous arterial waveform display with the use of a finger cuff. Invasive mean arterial blood pressure measurement was done by cannulation of the radial artery and direct transduction of the systemic arterial pressure waveform.Measurements and Main Results3 mins.Conclusions3 mins were noted. Concerning the considerable risk for arterial cannulation, our preliminary data demonstrate that the test instrument (PORTAPRES Registered Trademark, TNO Biomedical Instrumentation Research Unit; The Netherlands) is an advance in noninvasive monitoring of critically ill patients and may be useful in most emergency clinical settings.(Crit Care Med 1996; 24:1684-1689)