Der Anaesthesist
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Randomized Controlled Trial Clinical Trial
[Does controlled hypotension with nitroprusside affect platelet function?].
Induced hypotension is an accepted technique to reduce intraoperative blood loss and thereby ensures satisfactory operating conditions, especially in microscopic interventions. Sodium nitroprusside (NP), which is often used for induced hypotension, was reported to inhibit platelet aggregation in vitro. Impairment of platelet function implies a higher bleeding risk, which would make the use of NP for induced hypotension questionable. ⋯ In contradiction to in vitro studies using high concentrations of NP, we could not find a decrease in platelet aggregation due to hypotensive anaesthesia with this drug in vivo. In the control group a significant increase in platelet aggregation was observed, which was probably counteracted in the hypotensive patients by the interaction of NP with cyclic guanosine monophosphate (c-GMP). NP augments the intracellular concentration of c-GMP, which is known to decrease platelet aggregation.
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BACKGROUND AND METHODS. Small, periodic fluctuations in heart rate are well known to physicians, the respiratory sinus arrhythmia (RSA) being the most easily detectable form of this heart rate variability (HRV). Since it is caused by changing activity of the autonomic nervous system (ANS) controlling heart rate, HRV is investigated to gain information on the functional states of the ANS. ⋯ Since is also a striking reduction produced by most anaesthetic agents, RSA and HRV are investigated as measures of anaesthetic depth. There are contradictory data on the influence of ventilation, medication, and co-existing disease on the spectrum, and thus validation of the method is still to be achieved. It has, however, been proven useful in some studies as a parameter for risk assessment of perioperative or post-infarction cardiovascular complications.
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Clinical Trial
[The determination of total protein is not a suitable diagnosis for the treatment of hypoalbuminemia in intensive care patients].
In clinical practice, the administration of supplementary albumin often depends on the measured plasma concentration of total protein (TPC). A TPC of less than 5 g/dl is generally accepted as an indication for albumin therapy, assuming an albumin concentration of less than 2.5 g/dl. However, a physiological relation between TPC and albumin cannot be expected in critically ill patients, and thus, measurement of TPC may be misleading as an indicator for the use of albumin. ⋯ In other cases, a need for albumin would be assumed from a reduced TPC even though the albumin concentration still exceeded 2.5 g/dl. Therefore, determination of TPC is not a suitable indicator of the need for albumin replacement. As a result, we suggest routine determination of albumin concentrations instead of TPC.
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Clinical Trial
[The laryngeal mask airway in the difficult intubation. The results of a prospective study].
The laryngeal mask airway (LMA) was prospectively used in patients who were difficult to intubate to evaluate whether it improves ventilation compared to a face mask, facilitates fibreoptic intubation, and how often blind intubation would be possible. ⋯ The LMA improves ventilation, facilitates fibreoptic intubation, and offers the possibility for blind endotracheal intubation in difficult to intubate patients. Blind intubation though the LMA has to be practised extensively to have a high success rate. The LMA represents an additional aid for the anaesthetic management of patients who are difficult to intubate.
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Case Reports
[Cerebral monitoring with trancranial doppler-sonography and cerebrovenous oximetry during resuscitation].
This case report describes cerebral monitoring of intracranial haemodynamics using transcranial Doppler sonography (TCD) and jugular bulb oxygen saturation (SjO2) by fiberoptic jugular bulb oximetry during cardiac arrest following cardiac surgery involving cardiopulmonary bypass (CPB). CPB for aortic valve replacement and coronary artery bypass grafting was performed in a 63-year-old patient previously operated upon for heart disease. Mean blood flow velocity was measured in the middle cerebral artery using a bidirectional 2 MHz TCD system. ⋯ Following extrathoracic cardiac resuscitation, systolic "spikes", loss of the diastolic flow profile, and no increase in SjO2 were recorded by the monitors, indicating cerebral circulatory arrest. However, a normal flow profile with increasing diastolic portions and an increase in SjO2 to 52% were seen following optimisation of the open thorax cardiac resuscitation. This monitoring may be able to give information to optimise therapy during CPR to avoid ischaemic cerebral injury.