One subject was exposed for six days to increasing levels of CO2, rising at a constant rate from 0.03 to 3.0% CO2 within a 15-h period followed by 9 h of air breathing. To assess acid-base parameters, arterialized capillary blood was taken from a finger twice daily (at 8 a.m. and 11 p.m.) at times corresponding to the beginning and end of the intermittent exposure to CO2. Venous blood samples w...

BACKGROUND There is little information concerning the carbon dioxide-related effects on respiratory mechanics in anesthetized, paralyzed subjects; however, hypocapnia or hypercapnia is often permitted in patients with severe brain injury or acute respiratory distress syndrome. Therefore, the carbon dioxide dependence of respiratory mechanics in healthy anesthetized, paralyzed subjects was inves...

Ear lobe blood pHa, PaCo2, PaO2, and O2 saturation (SaO2) were measured in healthy Caucasians and Sherpas at 3400 m (Namche Bazaar, Nepal, n = 4/5), 5050 m (Pyramid Laboratory, Lobuche, Nepal, n = 20/5) and 6450 m (Camp II of Mt Everest, n = 11/7). In the investigated altitude range, pHa increased progressively with altitude from 7.463 +/- 0.005 (mean +/- SE) to 7.496 +/- 0.006 in Caucasians wh...

The effects of intermittent negative pressure ventilation have been studied in 20 patients with chronic obstructive pulmonary disease during an exacerbation of their disease. Measurements of arterial blood gas tensions and maximal inspiratory pressure (MIP) were performed before and after six hours of negative pressure ventilation or standard treatment (control day) given in random order on two...

BACKGROUND There are no controlled trials of the use of different modes of nasal intermittent positive pressure ventilation (NIPPV) in patients with exacerbations of chronic obstructive pulmonary disease (COPD). This study describes the effect on blood gas tensions of four different modes of nasal ventilation. METHODS Twelve patients with acute exacerbations of COPD were studied (mean (SD) FE...

STUDY OBJECTIVE to assess the accuracy of nasal capnography for the monitoring of ventilation in extubated morbidly obese patients, following bariatric surgery. DESIGN prospective descriptive study. SETTING Post-anesthesia care unit. PATIENTS 25 consecutive morbidly obese patients admitted to the PACU after open bariatric surgery. INTERVENTION Patients had a nasal cannula designed to ad...

In order to examine the role of respiratory oscillation of PaCO2 (CO2 oscillation) in the control of respiration, we performed veno-venous bypass using a membrane lung in 10 anesthetized paralyzed dogs, where the dog was put on fixed mechanical ventilation so that we could keep average PaCO2 and PaO2 constant by adjusting FICO2 and FIO2 during CO2 loading/unloading. By venous CO2 loading/unload...

Regional cerebral blood flow was simultaneously determined using the stable xenon computed tomographic and the radioactive microsphere techniques over a wide range of blood flow rates (less than 10-greater than 300 ml/100 g/min) in 12 baboons under conditions of normocapnia, hypocapnia, and hypercapnia. A total of 31 pairs of determinations were made. After anesthetic and surgical preparation o...