Anaesthesia
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Randomized Controlled Trial
The effect of posture and anaesthetic technique on the surgical pleth index.
The surgical pleth index has been shown to correlate with surrogate variables of nociception during general anaesthesia, and it has been suggested to be of use as a depth of anaesthesia monitor. However, little is known about confounding factors. As the main determining variables are based on both central and peripheral autonomic regulatory mechanisms, we hypothesised that changing a patient`s posture may produce a marked effect. ⋯ Mean (SD) values of the surgical pleth index after adoption of the lithotomy position were reduced from 57 (22) to 21 (6) under general anaesthesia, 63 (15) to 31 (9) under spinal anaesthesia alone, and 52 (14) to 22 (8) under spinal anaesthesia with sedation (all p < 0.01). In healthy volunteers, the surgical pleth index increased from 37 (13) to 57 (11) (p < 0.01) after 30° head-up tilt and was reduced from 35 (11) to 25 (11) after head-down tilt (p < 0.05). Change in posture has a marked effect on the surgical pleth index which lasts for at least 45 min, and this must be considered when interpreting the displayed values.
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Significant recent interest has focussed on improving outcomes after emergency laparotomy. This retrospective database analysis estimated the annual incidence and associated inpatient costs of emergency laparotomy in England. Demographic, process and outcome data were collected for all patients undergoing emergency laparotomy in Brighton for two calendar years (2009-2010). ⋯ We also found that patients > 70 years (46%) had significantly higher 30-day postoperative mortality (18% vs 6%, p < 0.0001), significantly prolonged median (IQR [range]) length of stay (15 (10-26 [1-123]) days vs 12 (7-22 [1-176]) days, p < 0.001) and incurred higher costs (median (IQR [range]) £9667 (6620-15 732 [1920-103 624]) vs £7467 (4975-14 251 [1178-118 060]), p < 0.001). Emergency laparotomy is a common procedure associated with considerable cost, particularly among elderly patients. A National Emergency Laparotomy Database will help provide an evidence base on which to improve clinical outcome and cost efficiency.
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Brain natriuretic peptide has vasodilatory properties and may thus increase splanchnic perfusion and oxygenation. We compared the effects of recombinant brain natriuretic peptide on gastric mucosal microvascular haemoglobin oxygenation (reflectance spectrophotometry) and systemic variables with those of equi-hypotensive doses of two other vasodilators (nitroglycerine and dihydralazine). Chronically instrumented, healthy dogs were randomly allocated to receive on different days, one of the three drugs (nitroglycerine and dihydralazine doses titrated to reduce mean arterial pressure by ∼20%). ⋯ In contrast, the other vasodilators either did not increase gastric mucosal microvascular haemoglobin oxygenation at all (nitroglycerine), or did so only with marked increases in other systemic haemodynamic variables (dihydralazine). Our data suggest a potential role of recombinant brain natriuretic peptide selectively for increasing microvascular mucosal oxygenation. Studies are required to extend these findings to the clinical setting.