Atropine was given i.v. to 35 spontaneously breathing healthy adults anaesthetized with enflurane to determine if it would reduce PaCO2 by improving gas exchange. Five minutes after administration of atropine, PaCO2 decreased from mean 7.18 to 6.65 kPa (-7%), while mean VE increased from 4.8 to 6.1 litre min-1 (+27%). These changes were maintained 15 min later in the 20 patients studied at that...

Introduction Both hypoand hypercapnia can be deleterious to brain injured patients. Due to the variability of CO2 production and elimination and to the unpredictable effects of ventilator settings changes, strict arterial CO2 partial pressure (PaCO2) control is difficult to obtain. Conceivably, using expired (end-tidal) CO2 as the input signal of closed-loop ventilation (Intellivent-ASV) should...

We studied 15 patients undergoing cardiac surgery involving hypothermic cardiopulmonary bypass (CPB). Cerebral arteriovenous difference in oxygen content (AVDO2) was significantly less during CPB and for up to 18 h after operation compared with pre-CPB values (P < 0.05). There were no significant changes in mean jugular bulb oxyhaemoglobin saturation (SjvO2), cerebral arteriovenous difference i...

Ventilatory responses to CO2 during rest and exercise were studied in 10 marathon runners and 14 untrained subjects by the rebreathing method. The average responses of the untrained subjects and athletes at rest as meausred by the slope of VE-PACO2 curves were 1.86 and 1.12 liters/min-mmHg, the difference being statistically significant (p less than 0.05). During exercise the slope of VE-PACO2 ...

Definition of Respiratory Failure using PaO2 alone is confounded when patients are commenced on oxygen therapy prior to arterial blood gas (ABG) measurement. Furthermore, classification of Respiratory Failure as Type 1 or Type 2 using PaCO2 alone can give an inaccurate account of events as both types can co-exist. 100 consecutive presentations of acute respiratory distress were assessed initial...

The purpose of the present study was to determine the effect on breathing in the awake state of carotid body denervation (CBD) over 1-2 wk after denervation. Studies were completed on adult goats repeatedly before and 1) for 15 days after bilateral CBD (n = 8), 2) for 7 days after unilateral CBD (n = 5), and 3) for 15 days after sham CBD (n = 3). Absence of ventilatory stimulation when NaCN was...

Hyperventilation to extremely low arterial carbon dioxide tension (PaCO2) has been used in the management of persistent pulmonary hypertension in newborn infants. With progressive hypocarbia, cerebral vasoconstriction occurs, raising the concern that extreme hypocarbia may result in cerebral oxygen deprivation. Therefore, I evaluated regulation of the cerebral circulation during acute hypocarbi...

To the Editor:—Metabolic alkalemia is the most common acid–base disturbance among patients in the hospital. Because the disorder is associated with high mortality and morbidity, its prompt diagnosis and treatment is feasible. The expected physiologic compensation for a primary increase in serum bicarbonate concentration ([HCO3 ]), i.e., metabolic alkalosis, is hypoventilation that increases par...

We reviewed the literature on human cerebral circulation and oxygen metabolism, as measured by positron emission tomography (PET), with respect to normal values and of regulation of cerebral circulation. A multicenter study in Japan showed that between-center variations in cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic ra...

background: acute methanol poisoning is one of the most important chemical poisoning due to drinking of illegal and handmade alcoholic beverages in iran. the aim of this study was to evaluate clinical and biochemical parameters as prognostic factor in acute methanol poisoning. methods: a retrospective study was performed on acute methanol poisoning cases admitted to the loghman hakim hospital p...