Acta anaesthesiologica Scandinavica. Supplementum
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Acta Anaesthesiol Scand Suppl · Jan 1995
Oxygen and acid-base parameters of arterial and mixed venous blood, relevant versus redundant.
A complete pH and blood gas analysis of arterial and mixed venous blood may comprise more than forty different quantities. We have selected sixteen, including patient temperature. The arterial oxygen tension group includes the oxygen tension, fraction of oxygen in inspired air, and fraction of mixed venous blood in the arterial (total physiological veno-arterial shunting). ⋯ The mixed venous group includes mixed venous oxygen tension, and, when measured, cardiac output, and oxygen consumption rate. The acid-base status includes blood pH, arterial carbon dioxide tension, and extracellular base excess. Other quantities such as haemoglobin oxygen saturation, respiratory index, total oxygen concentration (oxygen content), oxygen extraction fraction, oxygen delivery, and several others, provide no essential additional clinical information and are therefore redundant.
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Acta Anaesthesiol Scand Suppl · Jan 1995
Review Comparative StudyFrom oxygen content to pulse oximetry: completing the picture in the newborn.
In recent years clinicians caring for sick preterm infants have come to depend on pulse oximetry to avoid hyperoxia, which means assuming saturation values for critical levels of oxygen tension. This prediction is made difficult by the shape of the haemoglobin-oxygen dissociation curve at critical values for arterial pO2 and by the effects of changes in acid-base balance on p50. Combined blood gas and co-oximetry measurements can be used to determine critical limits for pulse oximetry. ⋯ We demonstrated that, at 90% saturation, failure to use the fetal correction in the presence of high levels of fetal haemoglobin result in a 4% overestimate of saturation, with resultant underestimation of the safe range for pulse oximetry. Published values for extinction coefficients for fetal and adult blood at wavelengths used by pulse oximeters are inconsistent, but it appears that fetal haemoglobin does not bias pulse oximetry readings. Determining saturation limits by co-oximetry for use with pulse oximeters in preterm infants requires the description of the haemoglobin-oxygen dissociation curve with the correction for fetal haemoglobin.
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Acta Anaesthesiol Scand Suppl · Jan 1995
Randomized Controlled Trial Comparative Study Clinical TrialComparison of the neuromuscular effects of mivacurium and suxamethonium in infants and children.
We compared both the time course of neuromuscular blockade and the cardiovascular side-effects of suxamethonium and mivacurium during halothane and nitrous oxide anaesthesia in infants 2-12 months and children 1-12 years of age. Equipotent doses of mivacurium and suxamethonium were studied; 2.2 x ED95 was used in four groups of infants and children, while 3.4 x ED95 was used in two groups of children. Onset of neuromuscular block in infants was not significantly faster with suxamethonium than with mivacurium (P = 0.2). ⋯ Recovery of neuromuscular transmission to 25% of initial twitch height (T25) in infants and children was significantly faster after suxamethonium than after mivacurium, at 2.5 and 6 min, respectively (P < or = 0.05). In children given 3.4 x ED95 of suxamethonium or mivacurium, recovery from neuromuscular block was almost identical with the dose of 2.2 x ED95, with spontaneous recovery to T25 prolonged by only 0.5 min. No infant or child had hypotension after the mivacurium bolus dose.
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Acta Anaesthesiol Scand Suppl · Jan 1995
ReviewReversal of conscious sedation by flumazenil: current status and future prospects.
Flumazenil is safe and highly effective at reversing both benzodiazepine-induced sedation and amnesia. Bolus intravenous injection is the most appropriate technique when the goal is to fully reverse conscious sedation. Currently, the proven effective dose of flumazenil is 0.5 mg. ⋯ Depression of ventilatory responsiveness induced by benzodiazepines can be reversed effectively and promptly by flumazenil. Flumazenil must be immediately available as an emergency drug in any area where benzodiazepines are used. The clinical and economic benefits of elective and routine use of flumazenil have been demonstrated, but yet to gain widespread acceptance.
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Acta Anaesthesiol Scand Suppl · Jan 1995
Randomized Controlled Trial Clinical TrialIntubating conditions and neuromuscular effects of mivacurium during propofol-alfentanil anaesthesia.
In three groups of 20 patients, anaesthetized with propofol and alfentanil, tracheal intubation conditions and the onset of neuromuscular blockade after administration of three different doses of mivacurium chloride (0.11, 0.15, and 0.19 mg/kg = 1.5 x ED95, 2 x ED95, and 2.5 x ED95) were assessed. Intubation conditions were found to be clinically acceptable (good or excellent) in 83% of patients. ⋯ We conclude that mivacurium chloride allows smooth intubation in most patients within 60-90 s, even with the lowest dose (0.11 mg/kg), after a propofol-alfentanil induction of anaesthesia. However, because there were a few patients in whom intubating conditions were inadequate at 60-90 s, we are reluctant to advocate the preference of mivacurium chloride over suxamethonium for rapid sequence induction in emergency situations.