Anaesthesia and intensive care
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Anaesth Intensive Care · Dec 1999
Pulmonary mechanics in patients with prolonged mechanical ventilation requiring tracheostomy.
This study was performed to assess the changes in pulmonary mechanics before and after tracheostomy in patients with prolonged mechanical ventilation and to detect pre-tracheostomy physiologic factors that predict the outcome of weaning from mechanical ventilation. Pulmonary mechanics were recorded before and after tracheostomy in 20 patients. Work of breathing, mean airway resistance and pressure/time product showed no significant differences after tracheostomy. ⋯ A significant difference was also found in pre-tracheostomy compliance (Cstatic) (47.3 +/- 36.9 vs 28.8 +/- 16.5 ml/cmH2O). We concluded that tracheostomy changed pulmonary mechanics very little except for a fall in peak inspiratory pressure. Patients who had better underlying lung mechanics (higher Cstatic and lower PEEPi) had better chances of weaning from mechanical ventilation after tracheostomy.
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Anaesth Intensive Care · Dec 1999
Comparative StudyMeasurement of cardiac output by transoesophageal echocardiography: a comparison of two Doppler methods with thermodilution.
This study assessed the agreement between three methods of cardiac output (CO) measurement, thermodilution, the current clinical standard, and two transoesophageal echocardiographic techniques. Measurements were performed in 37 patients using thermodilution, continuous wave Doppler across the aortic valve and pulsed wave Doppler positioned in the left ventricular outflow tract. The aortic valve area was measured by direct planimetry, and the left ventricular outflow tract area was calculated from its diameter. ⋯ There was fixed bias but not proportional bias between pulsed wave and thermodilution methods (SDdiff 1.1 l/min). There was neither fixed nor proportional bias between pulsed wave and continuous wave Doppler methods (SDdiff 1.1 l/min). The transoesophageal Doppler methods described can be clinical alternatives to thermodilution cardiac output measurement.
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Epidural abscess is a rare complication of epidural block and occasionally presents in the post partum period. A case is described where a thoracolumbar abscess presented with backache and headache 10 days after an apparently uneventful block for labour and caesarean section. The abscess was treated medically with a satisfactory outcome. The literature is reviewed in order to assess several recent reports of infectious complications of epidural block in obstetric patients.
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Anaesth Intensive Care · Dec 1999
Case ReportsHumidification difficulties in two tracheostomized children.
Effective humidification is sometimes difficult to achieve in children when normal mechanisms are bypassed by having a tracheostomy in situ. The humidification options available in the paediatric population are heat and moisture exchangers (HMEs) and heated humidifiers, both of which are reviewed and discussed. ⋯ We outline the hospital and subsequent home management of two infants, both with tracheostomies in situ, who unsuccessfully trialed HMEs and subsequently achieved effective humidification with heated humidifiers. We propose that heated humidifiers would help more tracheostomized infants who are suffering from similar problems.
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Anaesth Intensive Care · Dec 1999
Complement activation by propofol and its effect during propofol anaesthesia.
We have examined whether propofol activates complement. In the first study, blood was mixed with saline, propofol or the lipid solvent for propofol, and the activated complement 3 (C3a) and 4 (C4a) concentrations in the supernatant were assayed. In the second study, blood and propofol were mixed with various levels of nafamostat mesilate (anti-complement agent) up to 0.3 mmol/l and the C3a was assayed. ⋯ This activation was not inhibited by any of the nafamostat concentrations used. There was no significant change in plasma C3a concentration during propofol anaesthesia. These results suggest that C3a is generated by the lipid solvent, but its accumulation during propofol anaesthesia is minimal.