pulse oximetry measures the relative concentration of arterial oxygenated hemoglobin and reduced hemoglobin. this paper presents the design of a pulse oximeter, which measures the presence of a third substance, carboxyhemoglobin (hbco), by unfiltered leds at 660 nm, 810 nm, and 940 nm. background information is given on the theory of pulse oximetry. theoretical approximations and calculations w...

Pulse oximetry is based on a relatively new concept, using the pulsatile variations in optical density of tissues in the red and infrared wavelengths to compute arterial oxygen saturation without need for calibration. The method was invented in 1972 by Takuo Aoyagi, a bioengineer, while he was working on an ear densitometer for recording dye dilution curves. Susumu Nakajima, a surgeon, and his ...

Pulse oximetry has become a standard of care in anesthetic, pediatric and neonatal practice (l,2). It measures the per cent saturation of hemoglobin based upon the Beer Lambart's spectrophotometric principle of differential absorption of red and infrared light waves (660 nm and 940 nm, respectively) by the oxyhemoglobin and reduced hemoglobin(3). Pulse oximetry has been recently adopted for con...

The introduction of the OxiMax® Pulse Oximetry System brought Nellcor’s fifth-generation pulse oximetry technology to market and marked a fundamental shift in one of the design tenets of pulse oximeters. In the first four generations of Nellcor® pulse oximetry, beginning with the N-100 Pulse Oximeter introduced in the early 1980s, we focused attention on the hardware and software algorithms tha...

The deployment of fingerprint sensors is increasingly becoming common and has now gained high user acceptance. However, fingerprint sensors are susceptible to spoofing using artificial materials or in worst case to the dismembered fingers. Fake/gummy fingerprints have shown to fool most commercial fingerprint systems. This paper proposes a new method of anti-spoofing using reliable liveness det...

A new system for measuring the oxygen saturation of blood within tissue has been developed, for a variety of patient monitoring applications. A particular unmet need is in the central nervous system, and this project aims to devise a means for measuring blood oxygen saturation in the brain tissue of patients recovering from neurosurgery or head injury. Coupling light sources and a photodetector...

BACKGROUND Lower extremity arterial disease (LEAD) is common and underdiagnosed in patients with diabetes mellitus and is associated with higher total mortality. METHODS We compared the accuracy of pulse oximetry, the ankle-brachial index (ABI), and the combination of the two to diagnose LEAD in consecutive outpatients with type 2 diabetes who had no symptoms of LEAD, in a primary care settin...

We report a case of rheumatic heart disease with severe mitral stenosis having cyanosis and low oxygen saturation on pulse oximetry. The findings of clinical examination and low values on pulse oximetry were inconsistent with the findings of normal partial pressure of oxygen and oxygen saturation on arterial blood gas analysis, leading to diagnostic dilemma. In such clinical scenario, the anest...

The causes of hypoxaemia in children include the commonest causes of childhood illness: pneumonia and other acute respiratory infections, and neonatal illness, particularly sepsis, low birthweight, birth asphyxia and aspiration syndromes. The systematic use of pulse oximetry to monitor and treat children in resource-poor developing countries, when coupled with a reliable oxygen supply, improves...