Synchronizing Gait with Cardiac Cycle Phase Alters Heart Rate Response during Running.

Unlabelled: Timing foot strike to occur in synchrony with cardiac diastole may reduce left ventricular afterload and promote coronary and skeletal muscle perfusion.

Purpose: This study aimed to assess heart rate (HR) and metabolic responses to running when foot strikes are timed to occur exclusively during 1) the systolic phase of the cardiac cycle or 2) the diastolic phase.

Methods: Ten elite male distance runners performed a testing session on a treadmill at 4.

Pulse oximetry saturation patterns detect repetitive reductions in airflow.

Objective: Postoperative patients exhibiting signs or symptoms of obstructive sleep apnea (OSA) have been identified to be at increased risk for respiratory compromise. One of the key markers associated with OSA is repetitive reductions in airflow (RRiA). A real-time pulse oximeter saturation pattern recognition algorithm (OxiMax SPD™ intended for adult in-hospital use only) designed to detect specific signatures in the SpO(2) trend associated with RRiA may provide caregivers early indication of its presence so they can treat the patient appropriately.

Accuracy of methemoglobin detection by pulse CO-oximetry during hypoxia.

Background: Methemoglobin in the blood cannot be detected by conventional pulse oximetry, although it can bias the oximeter's estimate (Spo2) of the true arterial functional oxygen saturation (Sao2). A recently introduced "Pulse CO-Oximeter" (Masimo Rainbow SET(R) Radical-7 Pulse CO-Oximeter, Masimo Corp., Irvine, CA) is intended to additionally monitor noninvasively the fractional carboxyhemoglobin and methemoglobin content in blood.

The light-tissue interaction of pulse oximetry.

The underlying science of pulse oximetry is based on a simple manipulation of the Lambert-Beer law, which describes the attenuation of light traveling through a mixture of absorbers. Signals from detected red and infrared light that has traveled through blood-perfused tissues are used to estimate the underlying arterial hemoglobin oxygen saturation. However, light scatters in tissue and influences some of the simplifications made in determining this relationship.

Forehead pulse oximetry: Headband use helps alleviate false low readings likely related to venous pulsation artifact.

Background: This study investigated whether a tensioning headband that applies up to 20 mmHg pressure over a forehead pulse oximetry sensor could improve arterial hemoglobin oxygen saturation reading accuracy in presence of venous pooling and pulsations at the forehead site.

Methods: Healthy volunteers were studied breathing room air in supine and various levels of negative incline (Trendelenburg position) using the forehead sensor with the headband adjusted to its maximum and minimum recommended pressure limits. Saturation readings obtained from the forehead sensor with the subjects supine and the headband in place were used as a baseline to compare the effects of negative incline on reading accuracy when using and not using the headband.