The time-course of thoracic volume changes (respiratory inductive plethysmograph) during relaxed expiration was studied in 11 intubated, paralysed, mechanically ventilated subjects. The semilog volume-time curves show that expiration is governed by two apparently separate mechanisms: one causes emptying of most of the expired volume (approximately 80%) with a time constant of 0.50 +/- 0.22 s fo...

IT IS WELL ESTABLISHED that vagally innervated mechanoreceptors in the lung influence respiratory frequency and the occurrence of spontaneous sighs (augmented breaths). Are these reflexes vitally important, or do they merely “fine tune” the respiratory pattern? The remarkable vitality and long-term survival of human patients and laboratory animals after denervation associated with lung transpla...

Respiratory-associated variations in stroke volume and pulse pressure are frequently used to predict the response to fluid administration. However, it has been demonstrated that low tidal volume ventilation may limit their use in patients with acute respiratory distress syndrome (ARDS). In this issue, a trial investigates the value of pulse pressure variation to predict fluid responsiveness in ...

Respiratory volume monitoring (RVM) has been developed to noninvasively measure minute ventilation (V̇E), tidal volume, and breathing frequency and to display real-time respiratory curves in nonintubated patients. Although RVM was originally developed for post-anesthesia and monitored anesthesia care, we describe 3 applications for this monitor in an otherwise austere setting at a missionary hos...

To understand the cardiovascular response to respiratory acidosis, we measured hemodynamics, left ventricular pressure, and left ventricular volume (three ultrasonic crystal pairs) during eucapnia and respiratory acidosis in 10 fentanyl-anesthetized open-chest dogs. Left ventricular contractility was assessed primarily by measuring the slope (Emax) and intercept (V0) of the left ventricular end...

Nutritional status deteriorates along with progression of emphysema, with the decline of body composition correlating with risk of disease-related events. Lung volume reduction surgery (LVRS), by improving respiratory function and recovering body composition, may influence long-term disease-related morbidity and mortality when compared to respiratory rehabilitation (RR). In this non-randomised ...

The effects of ten narcotic analgesics and three barbiturates have been investigated on respiratory rate, respiratory minute volume and blood Pco3 in the unanaesthetized rabbit. Both groups of drugs produced respiratory depression, and whilst the pattern of depression was similar for drugs of the same group, there were three main differences in the pattern of depression between the narcotic ana...

The effect of raising the airways resistance of 56 normal newborn babies by blocking alternate nostrils was studied by means of oesophageal intubation and the trunk plethysmograph. Increased resistance was associated with reduced respiratory rate and ventilation. A comparison was made of the response in different sleep states. In rapid eye movement (REM) sleep respiratory tidal volume decreased...

Introduction From literature we know that a cornerstone of the protective lung ventilation in Acute Respiratory Distress Syndrome (ARDS) patients [1] and during general anesthesia [2] is a low tidal volume. On the other hand, driving pressure seems to be the variable that best stratifies mortality risk [3]. Our hypothesis is that the combination of volume and pressure, that is the energy dissip...

Enhanced negative volume dependence of airway resistance is associated with bronchoconstriction in tracheostomized paralysed open-chest animals. Significant upper airways responses may be associated with bronchoconstriction and could thereby alter the pattern of volume dependence in spontaneously breathing subjects. The aim of the study was to test whether volume dependence of respiratory resis...