Specimens of Conger conger (L.) were exposed to environmental hypercapnia in a closed recirculating seawater system. Arterial plasma pH, Pco2 and bicarbonate concentration, as well as the net transfer of bicarbonate and ammonia between fish and ambient seawater, were monitored for 30 h of hypercapnia. The initial hypercapnia-induced reduction of arterial pH by about 0 4 pH units was restored to...

BACKGROUND Multiple studies have shown that cerebral tissue oxygen saturation (Sct(O(2))) is decreased after phenylephrine treatment. We hypothesized that the negative impact of phenylephrine administration on Sct(O(2)) is affected by arterial blood carbon dioxide partial pressure (Pa(CO(2))) because CO(2) is a powerful modulator of cerebrovascular tone. METHODS In 14 anaesthetized healthy pa...

Calibrated MRI techniques use the changes in cerebral blood flow (CBF) and blood oxygenation level-dependent (BOLD) signal evoked by a respiratory manipulation to extrapolate the total BOLD signal attributable to deoxyhemoglobin at rest (M). This parameter can then be used to estimate changes in the cerebral metabolic rate of oxygen consumption (CMRO(2)) based on task-induced BOLD and CBF signa...

Hypercapnia, elevated partial pressure of CO2 in blood and tissue, develops in many patients with chronic severe obstructive pulmonary disease and other advanced lung disorders. Patients with advanced disease frequently develop bacterial lung infections, and hypercapnia is a risk factor for mortality in such individuals. We previously demonstrated that hypercapnia suppresses induction of NF-κB-...

We report two cases where patients with an acute head injury developed hypercapnia as a result of the inappropriate use of the Magill breathing circuit. The Magill circuit is inefficient when used for controlled ventilation because the patient is ventilated with his own expired gas and develops hypercapnia. The suitability of alternative breathing systems are discussed.

In conscious rats, focal CO2 stimulation of the medullary raphe increases ventilation, while interference with serotonergic function here decreases the ventilatory response to systemic hypercapnia. We sought to determine whether repeated administration of a selective serotonin reuptake inhibitor in this region would increase the ventilatory response to hypercapnia in unanaesthetized rats. In ra...

Breathing-disordered states, such as in obstructive sleep apnea, which are cyclical in nature, have been postulated to induce neurocognitive morbidity in both pediatric and adult populations. The oscillatory nature of intermittent hypoxia, especially when chronic, may mimic the paradigm of ischemia-reperfusion in that tissues and cells are exposed to episodes of low and high O(2) and this may l...

BACKGROUND Chronic respiratory failure complicating sleep-disordered breathing in obese patients has important adverse clinical implications in terms of morbidity, mortality and healthcare utilisation. Screening strategies are essential to identify obese patients with chronic respiratory failure. METHOD Prospective data were collected from patients with obesity-related sleep-disordered breath...

We prospectively studied emergency hospitalizations due to acute exacerbations of chronic obstructive pulmonary disease (COPD) among 74 hypercapnic patients, in order to determine factors which predict reversal to normocapnia as a result of therapy. Clinical, arterial blood gas and pulmonary function data on presentation were compared to predischarge values among those 58 patients who survived ...