Anaesthesia
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Review Meta Analysis
A systematic review and meta-regression analysis of prophylactic gabapentin for postoperative pain.
We searched MEDLINE, Embase, CINAHL, AMED and CENTRAL databases until December 2014 and included 133 randomised controlled trials of peri-operative gabapentin vs placebo. Gabapentin reduced mean (95% CI) 24-h morphine-equivalent consumption by 8.44 (7.26-9.62) mg, p < 0.001, whereas more specific reductions in morphine equivalents were predicted (R(2) = 90%, p < 0.001) by the meta-regression equation: 3.73 + (-0.378 × control morphine consumption (mg)) + (-0.0023 × gabapentin dose (mg)) + (-1.917 × anaesthetic type), where 'anaesthetic type' is '1' for general anaesthesia and '0' for spinal anaesthesia. The type of surgery was not independently associated with gabapentin effect. ⋯ The risk ratios (95% CI) for postoperative nausea, vomiting, pruritus and sedation with gabapentin were: 0.78 (0.69-0.87), 0.67 (0.59-0.76), 0.64 (0.51-0.80) and 1.18 (1.09-1.28), respectively, p < 0.001 for all. Gabapentin reduced pre-operative anxiety and increased patient satisfaction on a 10-point scale by a mean (95% CI) of 1.52 (0.78-2.26) points and 0.89 (0.22-1.57) points, p < 0.001 and p = 0.01, respectively. All the effects of gabapentin may have been overestimated by statistically significant small study effects.
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We hypothesised that the genetic effect of single nucleotide polymorphisms in the TACR1 gene, which encodes NK1 receptors, could influence the sex difference in postoperative nausea and vomiting. Thirty-two selected single nucleotide polymorphisms were genotyped by the Sanger sequencing method in 200 patients who underwent lower abdominal surgery. The incidence and severity of postoperative nausea and vomiting were evaluated after surgery. ⋯ The TT haplotype defined by two single nucleotide polymorphisms, including the rs3755468-SNP, was associated with reduced incidence and severity of postoperative nausea and vomiting in female patients (p = 0.03). The rs3755468-SNP is located within the predicted oestrogen response element and a DNase I hypersensitive site. The single nucleotide polymorphisms in the TACR1 gene are associated with sex differences in postoperative nausea and vomiting and may help to elucidate the mechanisms underlying these differences.
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Increased levels of exhaled nitric oxide (eNO) may be a more objective predictor in identifying children at higher risk of peri-operative adverse respiratory events than the presence of risk factors such as recent cold or wheeze. Children with either none or ≥ 2 risk factors had eNO measured before surgery and any peri-operative adverse respiratory events were recorded. ⋯ The combination of both predictors did not improve the predictive capability for adverse respiratory events (OR 1.93 (95% CI 1.44-2.59), p < 0.001). We conclude that measuring eNO levels does not lead to improved prediction of adverse respiratory events and that, in routine clinical practice, an accurate history of risk factors remains the most appropriate tool for successfully identifying children at risk of peri-operative adverse respiratory events.
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Novel devices for small-lumen ventilation may enable effective inspiration and expiratory ventilation assistance despite airway obstruction. In this study, we investigated a porcine model of complete upper airway obstruction. After ethical approval, we randomly assigned 13 anaesthetised pigs either to small-lumen ventilation following airway obstruction (n = 8) for 30 min, or to volume-controlled ventilation (sham setting, n = 5). ⋯ Histopathology demonstrated considerable lung injury, predominantly through differences in the dorsal dependent lung regions. Small-lumen ventilation maintained adequate gas exchange in a porcine airway obstruction model. The use of this technique for 30 min by inexperienced clinicians was associated with considerable end-expiratory collapse leading to lung injury, and may also carry the risk of severe injury.