The use of a semidosed system (the Magill attachment) for positive pressure breathing was investigated. Various patterns of ventilation were used and their effects assessed by serial measurement of the arterial carbon dioxide. It was found that this could be kept within limits comparable to those found during normal sleep using a flow of fresh gases as low as 5 l./min. This result was most easi...

BACKGROUND Despite constant fluctuations in cardiac preload caused by the effects of respiration and changes in posture on venous return to the heart, arterial blood pressure remains remarkably constant. The effects of instantaneous lung volume (ILV) and variations of central venous pressure (CVP) on blood pressure (BP) were studied by use of frequency domain techniques to quantify the contribu...

Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopneas alternate with periods of hyperventilation, producing a waxing and waning pattern of tidal volume. This review focuses on the causes and consequences of Cheyne-Stokes respiration in patients with congestive heart failure, in whom the prevalence is strikingly high and ranges from 30% to 50%. Several f...

The use of sidestream infrared and paramagnetic clinical gas analyzers is widespread in anesthesiology and respiratory medicine. For most clinical applications, these instruments are entirely satisfactory. However, their ability to measure breath-by-breath volumetric gas fluxes, as required for measurement of airway dead space, oxygen uptake, and so on, is usually inferior to that of the mass s...

In conclusion, we believe the intermittent function of the Nellcor N-100 pulse oximeter noted during positive pressure ventilation associated with hypovolaemia in neonates and small children represents an important clinical observation which can help guide intraoperative fluid management. Anaesthetists should use this and other clinical signs to provide appropriate fluid administration, since t...

BACKGROUND Previous research has shown a reduction in blood pressure (BP) immediately after the practice of alternate nostril yoga breathing (ANYB) in normal healthy male volunteers and in hypertensive patients of both sexes. The BP during ANYB has not been recorded. MATERIAL/METHODS Participants were 26 male volunteers (group mean age ±SD, 23.8±3.5 years). We assessed (1) heart rate variabil...

Blood is a vital source for delivering oxygen and nutrients to trillions of cells in the body; this makes the function of the cardiovascular system essential to our existence. In the last few years, research interests were directed to exploring its behaviour under different types of stresses, i.e. mental and physical. In this study, we propose a closed-loop model built around the cardiovascular...

Transcutaneous partial oxygen tension (tc pO2) and skin blood flow (via heat clearance) were measured noninvasively in 22 male subjects who performed stress-inducing tasks (i.e. hand-grip exercise, cold pressor test, breath holding, hyperventilation and mirror-tracing). An analysis of variance and covariance was conducted for tc pO2, heat clearance, heart rate, respiration rate, finger pulse vo...

In rabbits which were initially conscious or lightly anaesthetized with pentobarbitone, ketamine respectively increased or did not change arterial pressure, whereas in mechanically ventilated animals there was prolonged depression of both pressure and pregangkioinic sympathetic activity. Although respiratory rate slowed during spontaneous ventilation, blood-gas changes were not responsible for ...