t of a single recruitment maneuver after an apnea test for the diagnosis of brain death’ by Paries and colleagues [1]. Th e ‘ideal’ apnea test (AT) should permit an increase in PaCO2 (partial pressure of carbon dioxide in arterial blood) but prevent a detrimental decrease in PaO2 (partial pressure of oxygen in arterial blood). We agree that a recruitment maneuver (RM) after the AT can improve o...

We investigated this hypothesis that arterial CO2 pressure (PaCO2) drives ventilation (V . E) with a time delay during recovery from short impulse-like exercise (10 s) with work load of 200 watts. V . E and end tidal CO2 pressure (PETCO2) were measured continuously during rest, warming up, exercise and recovery periods. PaCO2 was predicted (PaCO2 pre) from PETCO2 and tidal volume (VT). PETCO2 a...

We have compared the differences between end-tidal PE'CO2 and arterial PaCO2 carbon dioxide partial pressures during general anaesthesia using either a cuffed oropharyngeal airway (COPA) or a tracheal tube (TT) in spontaneously breathing adult patients. After induction of anaesthesia, a COPA was inserted in 20 patients who were allowed to breathe spontaneously. When steady state was reached, PE...

This study to evaluate the relationship between end-tidal carbon dioxide pressure (ETCO2) and arterial partial pressure of carbon dioxide (PaCO2) included 35 patients between the ages of 18 and 65 years, ASA grade 1 and 2, who had elective craniotomies. Measurements of PaCO2 and ETCO2 were taken simultaneously: 1) 10 minutes after induction of general anaesthesia, 2) after cranium opening prior...

Objects: The purpose of this study was to observe a correlation between PETCO2 and PaCO2 in intubated neonates under intermittent mandatory ventilation with spontaneous breathing. Material and methods: A total of 55 paired PETCO2 measured by mainstream capnometry and PaCO2 values were obtained from 4 intubated neonates in our neonatal intensive care units at Nagano Children’s Hospital, Nagano, ...

Nocturnal oxygen desaturation during the sleep is very frequent in patients affected by chronic obstructive pulmonary disease (COPD). Hypoventilation, rather than sleeping apnea, is commonly considered as the most relevant factor in the onset of nocturnal oxygen desaturation. On this topic, the Authors have carried on a study on the nocturnal hypoxemia in 70 hospitalized COPD patients with a me...

We have studied 14 female patients undergoing elective laparoscopy under general anaesthesia with peritoneal insufflation of carbon dioxide in order to examine changes in physiological deadspace (VDphys), arterial to end-tidal carbon dioxide partial pressure difference (PaCO2-PE' CO2) and PaCO2. VCO2 increased after insufflation of carbon dioxide with a mean (SD) maximum increase of 32 (28)% co...

BACKGROUND Physiological dead space (VD/VT) represents the fraction of ventilation not participating in gas exchange. In patients with acute respiratory distress syndrome (ARDS), VD/VT has prognostic value and can be used to guide ventilator settings. However, VD/VT is rarely calculated in clinical practice, because its measurement is perceived as challenging. Recently, a novel technique to cal...

Introduction Physiology of Carbon Dioxide PACO2 PaCO2 The Concept of Dead Space Measurement of Dead Space Bohr Enghoff Langley Alveolar Ejection Volume Causes of Elevated Dead Space in Mechanically Ventilated Patients Pulmonary Embolism COPD ARDS Effects of Mechanical Ventilation on Dead Space Effect of VT Effect of PEEP Effect of Inspiratory Flow Waveforms and End-Inspiratory Pause Prone Posit...

Background: Ventilator management for children with hypoxemic respiratory failure may benefit from ventilator protocols, which rely on blood gases. Accurate non-invasive estimates for pH or PaCO2 could allow frequent ventilator changes to optimize lung protective ventilation strategies. If these models are highly accurate, they can facilitate the development of closed-loop ventilator systems. W...