In the intact rat kidney, bicarbonate reabsorption in the early proximal tubule (EP) is strongly dependent on delivery. Independent of delivery, metabolic acidosis stimulates EP bicarbonate reabsorption. In this study, we investigated whether systemic pH changes induced by acute or chronic respiratory acid-base disorders also affect EP HCO3- reabsorption, independent of delivery (FLHCO3, filter...

In a study of the cerebral consequences of cardiopulmonary bypass (CPB), we have assessed cerebral blood flow (CBF) by intra-arterial Xenon 133 clearance, utilising a Novocerebrograph 10a, before, during and immediately following CPB. All patients (n = 51), under the care of a single surgical team underwent elective coronary revascularisation using a standardised anaesthetic and surgical protoc...

BACKGROUND Arterial carbon dioxide tension (PaCO2), oxygen tension (PaO2), and mean arterial pressure (MAP) are modifiable factors that affect cerebral blood flow (CBF), cerebral oxygen delivery, and potentially the course of brain injury after cardiac arrest. No evidence regarding optimal treatment targets exists. METHODS The Carbon dioxide, Oxygen, and Mean arterial pressure After Cardiac A...

BACKGROUND Central sleep apnea frequently occurs in patients with heart failure. Because it is not practical to perform sleep studies on all patients, readily available laboratory tests that predict sleep apnea would be clinically useful. Arterial PCO2 has a profound influence on breathing during sleep: When it decreases below a certain threshold, apnea occurs. OBJECTIVE To study the value of...

31 Hyperthermia during prolonged exercise leads to hyperventilation, which can reduce 32 arterial CO2 pressure (PaCO2) and, in turn, cerebral blood flow (CBF) and thermoregulatory 33 response. We investigated 1) whether humans can voluntarily suppress hyperthermic 34 hyperventilation during prolonged exercise and 2) the effects of voluntary breathing control on 35 PaCO2, CBF, sweating and skin ...

The aims were to examine the gas exchange and arterial blood gas abnormalities among patients with scoliosis, and the correlation of these abnormalities with age and severity of deformity. Means among 51 patients were as follows: age 25.4 +/- 17.5 yr, angle of scoliosis 80.2 +/- 29.9 (SD), vital capacity 1.94 +/- 0.91 (SD) (i.e. 60.6 +/- 19.2% of predicted), PaO2 85.8 +/- 12.0 (SD), PaCO2 42.4 ...

We hypothesized that reductions in arterial PCO2 (PaCO2) below the apnea threshold play a key role in the pathogenesis of idiopathic central sleep apnea syndrome (ICSAS). If so, we reasoned that raising PaCO2 would abolish apneas in these patients. Accordingly, patients with ICSAS were studied overnight on four occasions during which the fraction of end-tidal CO2 and transcutaneous PCO2 were me...

Radiometer Blood Micro-system 2 was used in studies designed to, (a) compare the mean blood gas and acid-base values of 38 normal horses and 20 horses with chronic obstructive pulmonary disease (COPD), (b) determine the means and standard deviations of blood gas and acid-base values of Thoroughbred horses in training, and (c) investigate the relationships between clinical data, blood gas values...

Thirty six small hydrogen sensitive electrodes were inserted into the brains of 6 cats to evaluate the local vascular response to change in PaCO2, of cortex, subcortical white matter, and caudate nucleus. Repeated measurements (617) of local cerebral blood flow (ICBF) were performed over a period of 12 weeks. Within a PaCO2 range from 19 to 96 mmHg the local response of CBF was linear in most o...