Anaesthesia
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Randomized Controlled Trial
Studies on the spread of local anaesthetic solution in transversus abdominis plane blocks.
The extent of analgesia provided by transversus abdominis plane blocks depends upon the site of injection and pattern of spread within the plane. There are currently a number of ultrasound-guided approaches in use, including an anterior oblique-subcostal approach, a mid-axillary approach and a more recently proposed posterior approach. We wished to determine whether the site of injection of local anaesthetic into the transversus abdominis plane affects the spread of the local anaesthetic within that plane, by studying the spread of a local anaesthetic and contrast solution in four groups of volunteers. ⋯ In contrast, the posterior approaches, using both landmark and ultrasound identifications, resulted in predominantly posterior spread of contrast around the quadratus lumborum to the paravertebral space from T5 to L1 vertebral levels. We concluded that the pattern of spread of local anaesthetic differs depending on the site of injection into the transversus abdominis plane. This may have important implications for the extent of analgesia produced with each approach.
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Randomized Controlled Trial
Low-dose desmopressin improves hypothermia-induced impairment of primary haemostasis in healthy volunteers.
Mild hypothermia (34-35 °C) increases peri-operative blood loss. We have previously demonstrated the beneficial effect of in vitro desmopressin on impairment of primary haemostasis associated with hypothermia. This study evaluated subcutaneous desmopressin in 52 healthy volunteers, randomly assigned to receive either normal saline or desmopressin 1.5, 5 or 15 μg (with 13 in each group). ⋯ Hypothermia at 32 °C prolonged mean (95% CI) closure times (for adenosine diphosphate/collagen by 11.3% (7.5-15.2%) and for adrenaline/collagen by 16.2% (11.3-21.2%); these changes were reversed by desmopressin. A very small dose was found to be effective (1.5 μg); this dose did not significantly change closure times at 37 °C, but fully prevented its prolongation at 32 °C. Subcutaneous desmopressin prevents the development of hypothermia-induced impairment of primary haemostasis.
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Randomized Controlled Trial
Postoperative respiratory and analgesic effects of dexmedetomidine or morphine for adenotonsillectomy in children with obstructive sleep apnoea.
The postoperative respiratory and analgesic effects of dexmedetomidine and morphine have not been compared in children with sleep apnoea having adenotonsillectomy. In a randomised double-blind study we recruited 60 children, aged 2-13 years, who received either intravenous dexmedetomidine 1 μg.kg(-1) or morphine 100 μg.kg(-1) on anaesthetic induction. End-tidal carbon dioxide, Children's Hospital of Eastern Ontario Pain Scale score and supplementary morphine administration were recorded every 15 min for 60 min postoperatively. ⋯ Mean (SD) pain scores were higher with dexmedetomidine (8.1 (2.0) immediately postoperatively and 6.7 (1.0) at 60 min vs 7.6 (1.8) and 6.3 (0.7), respectively, with morphine (p = 0.023)). More patients required supplementary morphine with dexmedetomidine (13/30 (43%) vs 21/30 (70%); p = 0.037). Postoperatively, dexmedetomidine produced less respiratory depression than morphine, but less effective analgesia.
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Randomized Controlled Trial
Insertion of six different supraglottic airway devices whilst wearing chemical, biological, radiation, nuclear-personal protective equipment: a manikin study.
Six different supraglottic airway devices: Combitube™, laryngeal mask airway, intubating laryngeal mask airway (Fastrach™), i-gel™, Laryngeal Tube™ and Pro-Seal™ laryngeal mask airway were assessed by 58 paramedic students for speed and ease of insertion in a manikin, whilst wearing either chemical, biological, radiation, nuclear-personal protective equipment (CBRN-PPE) or a standard uniform. All devices took significantly longer to insert when wearing CBRN-PPE compared with standard uniform (p < 0.001). ⋯ Whilst wearing CBRN-PPE the i-gel was the fastest device to insert with a mean (SD (95% CI)) insertion time of 19 (8 (17-21))s, p < 0.001, with the Combitube the slowest with mean (65 (23 (59-71))s. Wearing of CBRN-PPE has a negative impact on supraglottic airway insertion time.
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Randomized Controlled Trial
Clinical evaluation of stethoscope-guided inflation of tracheal tube cuffs.
Tracheal tube cuffs are commonly inflated to pressures exceeding the recommended upper limit of 30 cmH(2)O. We evaluated whether a stethoscope-guided method of cuff inflation results in pressures within the recommended range. Patients were randomly assigned to receive one of two methods of cuff inflation. ⋯ Twenty-five patients were recruited to each group. The median (IQR [range]) cuff pressure in the 'just seal' group was 34 (28-40 [18-49]) cmH(2)O, and in the stethoscope-guided group was 20 (20-26 [16-28]) cmH(2)O, p < 0.0001. The stethoscope-guided method of tracheal tube cuff inflation is a novel, simple technique that reliably results in acceptable tracheal cuff pressures.