Anaesthesia and intensive care
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Anaesth Intensive Care · Dec 1999
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of the reinforced and standard laryngeal mask airway: ease of insertion and the influence of head and neck position on oropharyngeal leak pressure and intracuff pressure.
We conducted a randomized, crossover study of 60 paralysed anaesthetized adult patients to compare ease of insertion for the reinforced (RLMA) and standard laryngeal mask airway (LMA). We also test the hypothesis that oropharyngeal leak pressure (OLP) and intracuff pressure (ICP) vary with head and neck position for the two devices. OLP and ICP were documented in four head and neck positions (neutral first, then flexion, extension and rotation in random order) for each device. ⋯ We conclude that ease of insertion is similar for the RLMA and LMA. OLP is higher with head/neck flexion and lower with extension for both devices and is associated with a similar change in ICP. We recommend assessing the efficacy of seal for all head and neck positions likely to be encountered prior to the start of surgery.
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Anaesth Intensive Care · Dec 1999
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of patient controlled epidural pethidine versus single dose epidural morphine for analgesia after caesarean section.
This double-blind, randomized study of analgesia after caesarean section compared patient controlled epidural analgesia with pethidine (15 mg of a 0.25% solution and a 10 minute lockout period) versus a single bolus of epidural morphine 4 mg. Data were collected on 78 patients at 2, 6, 8, and 24 hours postoperatively and analysed using the Wilcoxon rank sum test. ⋯ The incidence of pruritus (P < 0.001) was lower in the pethidine group at 2, 6, and 8 hours, with no difference by 24 hours. Therefore PCEA pethidine provides a useful alternative to single-dose morphine after caesarean section, particularly in those patients who have suffered severe morphine-induced pruritus previously.
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Anaesth Intensive Care · Dec 1999
Randomized Controlled Trial Clinical TrialPharmacokinetics of paracetamol in adults after cardiac surgery.
The pharmacokinetics of paracetamol in adults after cardiac surgery have not been described. Twenty patients were randomized to receive either paracetamol 2 g through a nasogastric tube and as a suppository eight hours later or vice versa. Arterial blood samples were taken at 0.5, one, two, four, six and eight hours after dosing. ⋯ Absorption after nasogastric administration was slow compared to healthy adults (Tabs 0.06 to 0.7 h) and the bioavailability was half that expected, due to nasogastric loss. Parameter estimates had large variability. Paracetamol is unlikely to have useful clinical impact in the majority of patients when standard doses (6 g/day) are given on day 1 after cardiac surgery.
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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.