Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Sep 2012
Increased intrathoracic pressure affects cerebral oxygenation following cardiac surgery.
Cerebral oximetry reflects circulatory stability during surgery. We evaluated whether frontal lobe oxygenation is influenced by a transient increase in intrathoracic pressure as induced by a lung recruitment manoeuvre. ⋯ A lung recruitment manoeuvre decreases frontal lobe oxygenation when MAP is low suggesting that with increased intrathoracic pressure, arterial pressure should be kept within the limits of cerebral autoregulation.
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Clin Physiol Funct Imaging · Sep 2012
Relationship between peak cardiac pumping capability and indices of cardio-respiratory fitness in healthy individuals.
Cardiac power output (CPO) is a unique and direct measure of overall cardiac function (i.e. cardiac pumping capability) that integrates both flow- and pressure-generating capacities of the heart. The present study assessed the relationship between peak exercise CPO and selected indices of cardio-respiratory fitness. Thirty-seven healthy adults (23 men and 14 women) performed an incremental exercise test to volitional fatigue using the Bruce protocol with gas exchange and ventilatory measurements. ⋯ Small but significant relationship was found between peak CPO and peak heart rate (r = 0·23, P<0·05). These findings suggest that only peak cardiac output and stroke volume truly reflect CPO. Other indices of cardio-respiratory fitness such as oxygen consumption, anaerobic threshold, oxygen pulse, minute ventilation, carbon dioxide production and heart rate should not be used as surrogates for overall cardiac function and pumping capability of the heart.