Acta anaesthesiologica Scandinavica
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The oxygenation of 48 elderly patients scheduled for cataract surgery under local anaesthesia was studied using pulse oximetry and nasopharyngeal oxygen measurement. After a control period the patients breathed supplemental oxygen 2 l/min and later 4 l/min, via either a face mask or a nasal catheter. ⋯ The surgical draping did not cause hypoxaemia and the 2 l/min oxygen flow was sufficient to cause hyperoxaemia in all patients. The face mask and nasal catheter appeared to be equally good in oxygenating the patients.
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Acta Anaesthesiol Scand · Feb 1991
Maternal and fetal plasma atrial natriuretic peptide concentrations during elective caesarean section.
Atrial natriuretic peptide (ANP) is stored in the atrial cardiocyte and is capable of exerting potent, selective, and transient effects on fluid and electrolyte balance and on blood pressure. Because fluid shifts and hemodynamic adjustments occur during parturition, ANP might play a homeostatic role in the parturient and fetoplacental unit. We measured maternal and fetal plasma ANP concentrations in 19 parturients during elective caesarean section. ⋯ There was a significant correlation between the volume of maternal Ringer's lactate infusion received and maternal ANP concentration. A significant correlation was seen between the total dose of ephedrine administered acutely prior to delivery and the UA ANP concentration. These data suggest that: 1) increased blood volume during pregnancy is associated with increased maternal plasma ANP levels, and 2) the fetus can produce its own ANP, and is thereby capable of responding to ANP stimulating factors.