An improved pulse oximeter provides for simultaneous, noninvasive oxygen status
and photoplethysmograph measurements at both single and multiple sites. In particular,
this multiple-site, multiple-parameter pulse oximeter, or "stereo pulse oximeter"
simultaneously measures both arterial and venous oxygen saturation at any specific
site and generates a corresponding plethysmograph waveform. A corresponding computation
of arterial minus venous oxygen saturation is particularly advantageous for oxygen
therapy management. An active pulse-inducing mechanism having a scattering-limited
drive generates a consistent pulsatile venous signal utilized for the venous blood
measurements. The stereo pulse oximeter also measures arterial oxygen saturation
and plethysmograph shape parameters across multiple sites. A corresponding calculation
of delta arterial saturation and comparison of plethysmograph shape parameters
between multiple sites is particularly advantageous for the detection and management
of persistent pulmonary hypertension in neonates (PPHN), a patent ductus arteriosis
(PDA), and aortic coarctation.
