OBJECTIVE Hypercapnia resulting from protective ventilation in acute respiratory distress syndrome triggers metabolic pH compensation, which is not entirely characterized. We aimed to describe this metabolic compensation. METHODS The data were retrieved from a prospective collected database. Variables from patients' admission and from hypercapnia installation until the third day after install...

BACKGROUND Tissue oxygenation is the primary determinant of wound infection risk. Mild hypercapnia markedly improves cutaneous, subcutaneous (s.c.), and muscular tissue oxygenation in volunteers and patients. However, relative contributions of increased cardiac output and peripheral vasodilation to this response remains unknown. We thus tested the hypothesis that increased cardiac output is the...

Aging is associated with decreased vascular compliance and diminished neurovascular- and hypercapnia-evoked cerebral blood flow (CBF) responses. However, the interplay between arterial stiffness and reduced CBF responses is poorly understood. It was hypothesized that increased cerebral arterial stiffness is associated with reduced evoked responses to both, a flashing checkerboard visual stimula...

It has been stated that hypercapnia increases the permeability of the bloodbrain barrier to several compounds, e.g., trypan blue,' sulphate2 and iodinated serum albumin."' The experiments just cited have shown that during hypercapnia more of the substance under study has passed from blood into the brain tissue than in control animals, but such an effect could have been due to the expansion of t...

Although acute respiratory acidosis may be a sign of impending respiratory failure in spontaneously breathing patients, it is commonly encountered in intubated patients with acute lung injury (ALI). This is especially the case now that limiting tidal volumes and airway pressures have been proven to reduce mortality in ALI, presumably by reducing additional lung injury caused by mechanical venti...

Although sympathetic vasomotor discharge has respiratory modulation, the site(s) responsible for this cardiorespiratory interaction is unknown. One likely source for this coupling is the rostral ventral lateral medulla (RVLM), where presympathetic neurons originate in close apposition to respiratory neurons. The current study tested the hypothesis that RVLM bulbospinal neurons are modulated by ...

OBJECTIVE Permissive hypercapnia is a respiratory-care strategy that is used to reduce the risk for lung injury. The goal of this study was to evaluate whether permissive hypercapnia is associated with higher risk for intraventricular hemorrhage and early childhood behavioral and functional problems than normocapnia among very low birth weight infants. METHODS Very low birth weight infants fr...

Mitochondrial plasticity plays a central role in setting the capacity for acclimation of aerobic metabolism in ectotherms in response to environmental changes. We still lack a clear picture if and to what extent the energy metabolism and mitochondrial enzymes of Antarctic fish can compensate for changing temperatures or PCO2 and whether capacities for compensation differ between tissues. We the...

BACKGROUND Loss of medullary sympathoexcitatory neurons may contribute to baroreflex failure, leading to orthostatic hypotension in multiple-system atrophy (MSA). The cardiovascular responses to chemoreflex activation in MSA have not been explored to date. OBJECTIVES To determine whether ventilatory and cardiovascular responses to hypercapnia and hypoxia during wakefulness are systematically ...

Carbon dioxide (CO(2)) is increasingly being appreciated as an intracellular signaling molecule that affects inflammatory and immune responses. Elevated arterial CO(2) (hypercapnia) is encountered in a range of clinical conditions, including chronic obstructive pulmonary disease, and as a consequence of therapeutic ventilation in acute respiratory distress syndrome. In patients suffering from t...