Anaesthesia
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Randomized Controlled Trial Comparative Study
A randomised controlled trial comparing the effects of propofol with isoflurane in patients with diastolic dysfunction undergoing coronary artery bypass graft surgery.
There is a strong association between pre-operative diastolic dysfunction and difficulty in weaning from cardiopulmonary bypass. We compared the effects of propofol and isoflurane on left ventricular diastolic function in patients with pre-existing diastolic dysfunction undergoing coronary artery bypass grafting. We randomly allocated 60 patients to receive either propofol or isoflurane anaesthesia, and assessed left ventricular diastolic function using transoesophageal echocardiography. ⋯ Both propofol and isoflurane improved left ventricular diastolic function as evidenced by significant increases in E/A ratios, and significant decreases in deceleration time and isovolumetric relaxation time; the improvement was greater in the isoflurane group (between groups, p = 0.001 for both E/A ratio and deceleration time at T1 and T2 and p = 0.006 for isovolumetric relaxation time at both T1 and T2 ). Furthermore, Em/Am ratio, S, D and S/D ratios were significantly better in the isoflurane group. The administration of isoflurane during cardiac surgery improves diastolic function comparatively more than propofol.
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Observational Study
Changes in qualitative and quantitative ultrasound assessment of the gastric antrum before and after elective caesarean section in term pregnant women: a prospective cohort study.
Ultrasound measurement of the antral cross-sectional area allows a quantitative estimate of gastric contents in non-pregnant adults, but this relationship may be affected by compression of the stomach exerted by the gravid uterus during pregnancy. This study aimed to assess differences in quantitative (Perlas score) and qualitative (antral cross-sectional area) ultrasound assessments of the gastric antrum performed immediately before and after caesarean section. Forty-three women having elective caesarean section performed under spinal anaesthesia were studied in the semirecumbent and semirecumbent-right lateral positions. ⋯ The distance between the skin and the antrum, and the aorta and the antrum, decreased significantly in both positions after surgery. We suggest that our results indicate that stomach contents remain largely unchanged in women having elective caesarean section, but antral cross-sectional area decreases, especially in the semirecumbent position, related to a change in the position of the stomach within the abdomen. This implies that the relationship of antral cross-sectional area to volume of stomach contents, which has been determined for non-pregnant subjects, may not apply in term pregnant women.
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The unique pharmacology of remifentanil makes it a popular intra-operative analgesic. Short-acting opioids like remifentanil have been associated with acute opioid tolerance and/or opioid-induced hyperalgesia, two phenomena which have different mechanisms and are pharmacologically distinct. Clinical studies show heterogeneity of remifentanil infusion regimens, durations of infusion, maintenance of anaesthesia, cumulative dose of remifentanil and pain measures, which makes it difficult to draw conclusions about the incidence of acute tolerance or hyperalgesia. ⋯ Infusion rates greater than 0.2 μg.kg-1 .min-1 are characterised by lower mechanical/pressure/cold/pain thresholds, which suggests hyperalgesia. The use of concurrent multimodal analgesia, especially N-methyl-D-aspartate receptor antagonists, may be an effective preventive strategy. The clinical significance and long-term consequences of these entities is still uncertain.
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Controlled Clinical Trial
High-flow humidified nasal oxygenation vs. standard face mask oxygenation.
Ten healthy volunteers received oxygen for 1 min, 2 min and 3 min at 10 l.min-1 via a face mask, or humidified oxygen at 60 l.min-1 via nasal prongs (OptiflowTM ) with the mouth closed and with the mouth open. The mean (SD) end-tidal oxygen partial pressure after 3 min face mask and Optiflow oxygenation, with mouth closed and open, were: 88.5 (6.2) kPa; 85.6 (6.4) kPa and 48.7 (26.4) kPa, respectively, p = 0.001. The equivalent mean (SD) transcutaneous oxygen partial pressures were: 34.6 (5.4) kPa; 36.4 (6.5) kPa and 25.5 (15.7) kPa, respectively, p = 0.03. High-flow humidified nasal oxygenation for 3 min with the mouth closed was as effective as 3 min face mask oxygenation.
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Implementation of a quality improvement bundle for peri-operative management of emergency laparotomy (ELPQuIC) improved mortality in a previous study. We used data from one site that participated in that study to examine whether it was associated with the cost of care. We collected data from 396 patients: 144 before, 144 during and 108 after implementation of the bundle. ⋯ The costs per patient and per survivor did not differ between the time periods, p = 0.87 and p = 0.17, respectively. Costs were similar for patients aged < 80 years vs. ≥ 80 years. Implementation of a quality improvement bundle for emergency laparotomy has the capacity to save lives without increasing hospital costs.