A periodic increase in blood pressure (BP) occurs during apneic episodes in patients with obstructive sleep apnea (OSA). Several factors including hypoxemia and an increase in heart rate (HR) were reported to be responsible for this increased BP. To examine the contribution of these two factors in increasing BP, 35 healthy male subjects (mean age±SD= 23.64±3.80) were studied in three experi...

The emperor penguin (Aptenodytes forsteri) thrives in the Antarctic underwater environment, diving to depths greater than 500 m and for durations longer than 23 min. To examine mechanisms underlying the exceptional diving ability of this species and further describe blood oxygen (O2) transport and depletion while diving, we characterized the O2-hemoglobin (Hb) dissociation curve of the emperor ...

PURPOSE OF REVIEW Continuous wave near infrared spectroscopy (CW NIRS) provides non-invasive technology to measure relative changes in oxy- and deoxy-haemoglobin in a dynamic environment. This allows determination of local skeletal muscle O2 saturation, muscle oxygen consumption ([Formula: see text]) and blood flow. This article provides a brief overview of the use of CW NIRS to measure exercis...

BACKGROUND Exercise capacity as measured by peak oxygen uptake (Vo2) is similarly impaired in patients with heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). However, characterization of how each component of Vo2 changes in response to incremental exercise in HFpEF versus HFrEF has not been previously defined. We hypothesized that a...

PURPOSE This study compared the effect of supplemental oxygen (O2) on pediatric patients' apnea status and oxyhemoglobin saturation during: 1) conscious sedation for dental procedures and 2) the recovery period following sedation. METHODS Fourteen child patients (mean age 42 months) sedated with 50 mg/Kg chloral hydrate, 25 mg hydroxyzine pamoate, and 1.5 mg/Kg meperidine were treated for two...

BACKGROUND: The present study was undertaken to examine the feasibility of venous oxygen measurements in the inferior vena cava (IVC) via a catheter through the umbilical vein. This may serve as a proxy for mixed venous oxygenation and the complications of right atrial cannulation can be avoided at the same time. It has the added advantage of not being affected by atrial right-left shunting. RE...

The aim of the study was to investigate hypoxaemia in chronic obstructive pulmonary disease patients during a commercial flight. The effect of a commercial flight, lasting 5 h 40 min, on arterial blood gas levels and symptoms in 18 chronic obstructive pulmonary disease patients with a pre-flight percutaneous oxygen saturation of 94% and self-reported ability to walk 50 m without severe dyspnoea...

This study aimed to investigate the effect of periodic breathing (PB) at high altitude on sleep structure and arterial oxygen saturation (Sa,O2). Five healthy subjects underwent polysomnographic studies at sea level, and during the first and the fourth week of sojourn at 5,050 m. Their breathing pattern, sleep architecture and Sa,O2 were analysed. PB was detected in the high-altitude studies du...

To identify patients with respiratory disease, who may be at risk of developing respiratory distress during commercial air travel, a hypoxia inhalation test (HIT) can be performed. This paper reports our experience of using such a test combined with an interpretation algorithm in a routine respiratory function laboratory. Twenty-eight patients were studied. Baseline oxygen saturation (Sa,O2) wa...

Exposure of conscious animals to environmental heat stress increases portal venous radical content. The nature of the observed heat stress-inducible radical molecules suggests that hyperthermia produces cellular hypoxic stress in liver and intestine. To investigate this hypothesis, conscious rats bearing in-dwelling portal venous and femoral artery catheters were exposed to normothermic or hype...