European journal of anaesthesiology
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Dynamic hyperinflation, also called intrinsic PEEP (PEEPi,) occurs particularly when high tidal volumes or high respiratory rates are used during mechanical ventilation, although the phenomenon does occur at normal tidal volumes. It is not identified using existing monitoring such as the airway pressure but can be identified by occlusion of the expiratory port before the onset of the next positive pressure breath. Many factors contribute to PEEPi which has unfavourable effects on respiratory muscle activity. ⋯ Fine tuning of positive pressure ventilation, using low tidal volumes, short inspiratory times and adequate inspired oxygen are required. External PEEP, up to but not exceeding PEEPi, may be advisable. PEEP may be used therapeutically to improve gas exchange by inverse ratio ventilation or high frequency jet ventilation.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of the cardiovascular effects of intravenous, epidural and intrathecal sufentanil analgesia as a supplement to general anaesthesia for abdominal aortic aneurysm surgery.
Sixty ASA Grade II-III patients, without clinical symptoms of ventricular dysfunction and scheduled for elective bifemoral grafting for abdominal aneurysms, were allocated randomly to three equal groups to receive 150 micrograms sufentanil intravenously, epidurally or intrathecally. All patients received midazolam, vecuronium and nitrous oxide. Except for right ventricular stroke work index and pulmonary vascular resistance, all haemodynamic measurements decreased after sufentanil injection, but to the greatest extent after intravenous injection. ⋯ Despite the changes in systemic vascular resistance and the concordant alterations in cardiac index after aortic cross-clamping and revascularization, intrathecal sufentanil provided more stability in heart rate than intravenous or epidural sufentanil. In conclusion, intrathecal sufentanil produced the most stable heart rate. Two patients in the intrathecal group developed spinal headaches post-operatively.
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Randomized Controlled Trial Clinical Trial
Pre-oxygenation: an easy method for all elective patients.
The transparent plastic facemask has been investigated as a pleasant method of pre-oxygenation for elective non-high risk cases in 60 healthy ASA I or II patients randomly allocated to two groups. The patients in the pre-oxgenated group (n = 30) received 8 litre min-1 oxygen through a plastic facemask for 3 min whereas those in a control group (n = 30) were not pre-oxygenated. In all patients anaesthesia was induced with propofol 2.5 mg kg-1, fentanyl 1 ug kg-1 and atracurium 0.6 mg kg-1. ⋯ Arterial saturation in the pre-oxygenated group rose significantly from a mean baseline value of 96.4 (+/- 0.9)% to 99 (+/- 0.8)% (P < 0.01) and then remained stable both after induction and intubation: 99.1 (+/- 0.8)% and 98.9 (+/- 1.1)% respectively. In the control group arterial saturation dropped sharply within 20 s following induction to a mean of 89.8 (+/- 3.1)%, and it was 30 s before arterial saturation reached the equivalent value in the pre-oxygenated group as a result of manual inflation of the lungs. An 8 litre min-1 oxygen flow via a standard transparent plastic facemask is a simple, feasible and acceptable method for routine pre-oxygenation for all elective cases.
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Randomized Controlled Trial Clinical Trial
The influence of Ringer's lactate and gelatin infusion on the internal fluid balance of healthy volunteers measured by a non-invasive conductivity technique.
Eight healthy male volunteers received in random order at an interval of 1 week 2 litres of Ringer's lactate or 0.8 litre of gelatin (Gelofusine) over half an hour, after overnight fasting. At the end of the infusion period, blood volume and mean arterial pressure had increased significantly in both groups but the increase in blood volume was more pronounced with the colloid. Extracellular fluid volume increased significantly after Ringer's lactate, while a significant decrease was noticed after gelatin. ⋯ It can be concluded that infusion of 0.8 litre of gelatin results in a larger and longer lasting increase in blood volume than 2 litres of Ringer's lactate, probably due to mobilization of extracellular fluid volume. It also leads to extracellular fluid accumulation. The decrease in blood volume after infusion is caused by increased urine production, since no changes were seen in intra- and extracellular fluid volume during this period.