Anaesthesia
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Randomized Controlled Trial Clinical Trial
The effects of intrathecal diamorphine on gastric emptying after elective Caesarean section.
This study investigated whether intrathecal diamorphine affects gastric emptying following elective Caesarean section. Forty women were randomly allocated to receive either diamorphine 300 microg or 0.9% saline as part of a standard spinal anaesthetic. Gastric emptying was measured in the immediate postoperative period using paracetamol absorption. ⋯ The time to maximum concentration (Tmax) was statistically longer in the diamorphine group (control 41.8, SD 20.8 min; diamorphine 72.6 SD 41.9 min; p < 0.01). During the 2-h study period, mean morphine consumption via a patient controlled analgesia device was significantly higher in the control group (control 9.3, SD 3.6 mg; diamorphine 2.1, SD 2.1 mg; p < 0.01). We conclude that intrathecal diamorphine may contribute to the delay in gastric emptying that occurs immediately following elective spinal Caesarean section.
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Comparative Study
Production of compound A and carbon monoxide in circle systems: an in vitro comparison of two carbon dioxide absorbents.
Two new generation carbon dioxide absorbents, DrägerSorb Free and Amsorb Plus, were studied in vitro for formation of compound A or carbon monoxide, during minimal gas flow (500 ml x min(-1)) with sevoflurane or desflurane. Compound A was assessed by gas chromatography/mass spectrometry and carbon monoxide with continuous infrared spectrometry. Fresh and dehydrated absorbents were studied. ⋯ For both absorbents, values of compound A were < 1 ppm and therefore below clinically significant levels, but were up to 0.25 ppm higher with DrägerSorb Free than with Amsorb Plus. Using dehydrated absorbents, values of compound A were about 50% lower than with fresh absorbents and were identical for DrägerSorb Free and Amsorb Plus. With dehydrated absorbents, no detectable carbon monoxide was found with desflurane.
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Cardiac output can be measured accurately by transpulmonary arterial thermodilution using the PiCCO (Pulsion Medical Systems, Munich, Germany) system with a femoral artery catheter. We have investigated the accuracy of a new 50 cm 4 French gauge radial artery catheter and the ability to use the system with a shorter radial catheter. We studied 18 patients who had undergone coronary artery surgery and made three simultaneous measurements of cardiac output by arterial thermodilution and with a pulmonary artery catheter. ⋯ We found close agreement between arterial thermodilution and pulmonary artery thermodilution with a mean (SD) bias of 0.38 (0.77) l x min(-1). Arterial thermodilution became unreliable once the catheter had been withdrawn by more than 5 cm. We conclude that cardiac output measurement with arterial thermodilution with a radial catheter is interchangeable with that derived from a pulmonary artery catheter, and that a centrally sited arterial catheter is required for accurate determination of cardiac output by transpulmonary arterial thermodilution.
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Comparative Study
Ventilation of a model lung using various cricothyrotomy devices.
In this study we developed a model lung to compare the effectiveness of ventilation using four different cricothyrotomy devices. The Ravussin 13G cannula (VBM Medical), the Quicktrach cannula 4 mm ID (VBM Medical), the Melker cannula 6 mm ID (Cook) and a cuffed tracheal tube 6 mm ID were used in turn to ventilate the model lung through a cricothyrotomy over a range of upper airway resistances. The 6 mm cuffed tracheal tube provided consistently good ventilation independent of upper airway resistance. ⋯ The Ravussin cannula could ventilate well with the jet ventilator with low upper airway resistance but could not ventilate at all with complete upper airway obstruction. The Quicktrach performed poorly with low upper airway resistance but well with increased upper airway resistance. With its easier insertion, fewer complications compared to a surgical cricothyrotomy, and the ability to use it with a standard anaesthetic circuit, the authors feel that the 6 mm Melker canula is the technique of choice for emergency trans-tracheal ventilation.
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We report the pre-operative preparation and anaesthetic management for resection of an intracerebral tumour during awake craniotomy in a 9-year-old boy. We believe this is the youngest patient reported to have undergone this procedure. ⋯ We conclude that the procedure can be performed safely and that it seems unacceptable to uphold an age restriction. We believe that it is the individual level of development of the child that determines suitability for this type of surgery.