Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Co-induction and laryngeal mask insertion. A comparison of thiopentone versus propofol.
Conditions for insertion of the laryngeal mask airway were assessed in 70 unpremedicated patients comparing the co-induction with midazolam-alfentanil-thiopentone and midazolam-alfentanil-propofol. Following pre-induction doses of midazolam 0.04 mg.kg-1 and alfentanil 10 micrograms.kg-1, patients received equipotent doses of either thiopentone or propofol. Whilst jaw relaxation and ease of laryngeal mask insertion were similar between the two groups, patients receiving propofol were less likely to have undesired responses requiring additional boluses of induction agent (p < 0.05). We conclude that, using these doses, propofol is superior to thiopentone for laryngeal mask airway insertion when using a co-induction technique.
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Randomized Controlled Trial Comparative Study Clinical Trial
Analgesia after day case laparoscopic sterilisation. A comparison of tramadol with paracetamol/dextropropoxyphene and paracetamol/codeine combinations.
In a prospective, double-blind trial we compared the analgesic efficacy of tramadol during the first 24 h after day case laparoscopic sterilisation with two commonly prescribed combination analgesics. Seventy-five women were allocated randomly to receive oral paracetamol 325 mg/dextropropoxyphene hydrochloride 32.5 mg, tramadol 50 mg or paracetamol 500 mg/codeine phosphate 30 mg as required after a standardised anaesthetic technique. There were no significant differences in average or worst pain, sleep disturbance, mobility, number of tablets taken, satisfaction or preference for stronger analgesia (26.2% of all patients). ⋯ There was a trend towards a lower incidence of central nervous system side-effects (drowsiness, dizziness, headache) in the paracetamol/codeine group. Tramadol may be considered an alternative analgesic for day case surgery although analgesic regimens of greater efficacy are required for many patients. The relative incidence of side-effects for tramadol and other analgesics requires further evaluation.
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Randomized Controlled Trial Clinical Trial
Reshaping the Macintosh blade using biomechanical modelling. A prospective comparative study in patients.
It has been demonstrated that during routine use of the Macintosh blade, great forces are exerted on the maxillary incisors. The aim of this study was, by using biomechanical modelling, to modify a standard Macintosh blade in order to reduce these forces. ⋯ The mean (SD) maximal forces exerted on the maxillary incisors were 12.7 (8.8) N in patients in the modified Macintosh group compared to 25.5 (17.8) N in the standard Macintosh group (p = 0.008). These results demonstrate that reducing the proximal step of the Macintosh laryngoscope results in a reduction of the forces exerted on the teeth and suggest that laryngoscope blades with a high proximal step might be more traumatic than blades in which the proximal step is reduced.
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Comparative Study Clinical Trial Controlled Clinical Trial
The peri-operative use of the oesophageal Doppler monitor in patients undergoing coronary artery revascularisation. A comparison with the continuous cardiac output monitor.
This study was carried out to evaluate the ease of use and reliability of cardiac output estimations performed by an oesophageal Doppler monitor and to compare its use with that of a continuous cardiac output pulmonary flotation catheter. Measurements were made during and after surgery in 16 patients scheduled to undergo coronary revascularisation. Both devices suffered significant intra-operative problems which led us to question their suitability as operating theatre monitors. After surgery the continuous cardiac output monitor provided stable results while the oesophageal Doppler monitor required the continuous presence of an experienced anaesthetist to ensure comparable cardiac output estimations.
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Clinical Trial
A noninvasive method for evaluating the effect of thoracotomy on shunt and ventilation perfusion inequality.
A new noninvasive method was used to evaluate gas exchange in 12 patients undergoing thoracotomy for a variety of surgical procedures. A plot of inspired oxygen partial pressure versus oxygen saturation was analysed to calculate the independent contribution of shunt and intermediate ventilation/perfusion ratio which occurs during general anaesthesia for thoracotomy. A model based on the inspired to arterial oxygen difference involving the shunt equation was used to show how the relationship between inspired oxygen partial pressure and oxygen saturation could be used to derive two parameters of oxygen exchange, the virtual shunt and an index of low ventilation/perfusion ratio. ⋯ Thoracotomy caused a mean increase in shunt from 13.8% to 20.8% and a worsening ventilation/perfusion ratio from 0.5 to 0.2, the magnitude of which depended on the underlying pathology. In two patients, the ventilation/perfusion ratio decreased to less than 0.1. The method enables the prediction of oxygen saturation at different inspired oxygen partial pressures and allows the two components of gas exchange to be isolated using simple routine measurements of inspired oxygen and pulse oximetry.