Pulse oximetry can be used to measure the arterial oxygen saturation of hemoglobin (SpO2) and pulse rate of a patient. Measurement of these characteristics is generally accomplished by use of a non-invasive electro-optical sensor which scatters red and infrared lights through an arterially perfused portion of the patient's tissue. The sensor then detects the differential amounts of red and infrared light that are photoelectrically absorbed by the tissue. Stated otherwise, the sensor detects the amount of red and infrared light that passes through the patient's tissue. The differential amounts absorbed are then used to calculate SpO2.
Pulse oximetry is commonly used as a monitoring device in emergency departments, intensive care units, observational units, and operating rooms. Most pulse oximeter probes are designed for prolonged and continuous monitoring of a patient's SpO2 and pulse rate. These probes are generally shaped as a clip for a finger or toe.
Congenital heart disease (CHD) affects 8 per 1,000 newborns and is one of the most common and serious types of birth defects. If diagnosed early, CHD can be managed with palliation or successful surgical repair for the majority of CHD-affected newborns. However, a missed or delayed diagnosis can be life threatening or result in long-term morbidities for CHD-affected newborns. Current clinical practice for detecting CHD in newborns relies on a clinician performing a physical examination before the child's discharge from the nursery. However, a significant number of newborns with CHD are missed by physical examination.
In recent years, health care professionals have found pulse oximetry an important screening tool to aid clinical examination for detecting some severe forms of CHD. In a 2007 survey of 1,086 pediatric cardiologists, the majority of respondents supported a mandate for universal screening by pulse oximetry before newborn discharge. In 2009, the American Heart Association and American Academy of Pediatrics jointly issued a scientific statement recommending routine pulse oximetry screening on the foot of asymptomatic newborns after 24 hours of life, but before hospital discharge. In 2011, the Secretary of Health and Human Services approved the addition of screening newborns for critical CHD by pulse oximetry to the Recommended Uniform Screening Panel.
The most commonly used pulse oximetry sensors require attachment to the fingers or toes of a patient by some sort of clip. For adults and older children, clip-type pulse oximetry sensors are typically not a problem. The fingers and toes of a newborn, however, are much too small for the clip-type pulse oximetry sensors that are commonly used on older children and adults to fit properly. Conventional approaches to fitting a clip-type pulse oximetry sensor on a newborn's finger/toe or hand/foot includes securing the sensor in place with adhesives or Velcro. Sensors secured with adhesives or Velcro, however, are generally single-use and therefore add substantial expenses to the universal screening of all newborns at hospital discharge. Moreover, securing pulse oximetry sensors on newborns in such a manner takes a considerable amount of time, which adds difficulty to the bigger picture of screening a large number of newborns. Furthermore, sensors that are secured to newborns with adhesives or Velcro are prone to motion artifacts and signal interferences from ambient light, both of which are unwanted in newborn screenings given that accurate and reliable results are needed to diagnose CHD-affected newborns.