Anaesthesia
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Invasive ventilation poses a risk of respiratory infection that can be drug-resistant. One means of reducing transmission of infection is the use of a breathing system filter. Filters are intended to be used with dry gas. ⋯ All the filters tested allowed free passage of both Candida albicans and coagulase-negative staphylococci. The median (IQR [range]) pressure required for fluid to flow across the filter varied greatly between different filter types (20 (0-48 [0-138]) cmH(2)O). We conclude that even large microorganisms pass across moist breathing system filters in conditions that are found in clinical practice.
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Randomized Controlled Trial
Pre-operative vitamin B infusion and prevention of nitrous oxide-induced homocysteine increase.
Nitrous oxide inactivates vitamin B(12) with detrimental consequences for folate and methionine metabolism, detectable by an increase in total plasma homocysteine. We hypothesised that a pre-operative vitamin B(12) and folate infusion prevents nitrous oxide-induced homocysteine increase. Sixty-three healthy patients having elective surgery were randomly allocated to receive either B-vitamin plus nitrous oxide; placebo plus nitrous oxide or placebo plus air. ⋯ After intravenous B-vitamin infusion, plasma vitamin B(12) and folate concentrations increased 35-fold and 12-fold, respectively, on the first postoperative measurement. Patients who received B-vitamins developed a similar increase (18%) in homocysteine after nitrous oxide (1.9 micromolxl(-1); 95% CI 0.2-3.6 micromolxl(-1)) as those who did not (22%; 2.7 micromolxl(-1); 95% CI 0.6-4.8 micromolxl(-1)). Patients not receiving nitrous oxide had no homocysteine change (0.5 micromolxl(-1); 95% CI -0.8-1.9 micromolxl(-1)), indicating that pre-operative intravenous B-vitamins may not prevent nitrous oxide-induced hyperhomocysteinaemia.
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Review Case Reports
Severe hypotension related to cell salvaged blood transfusion in obstetrics.
Intra-operative blood cell salvage has recently been adopted for use in women at risk of significant haemorrhage during caesarean section. It has also been advocated for use in those patients who refuse allogenic blood transfusion. ⋯ On starting the cell-salvaged blood transfusion, the blood pressure was noted to fall and this was temporally related to the transfusion of the cell-salvaged blood. We review the recent literature and case reports on hypotension related to cell-salvaged blood transfusion.
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Randomized Controlled Trial Comparative Study
Comparison of Flexiblade and Macintosh laryngoscopes: cervical extension angles during orotracheal intubation.
The Flexiblade(TM) is a new laryngoscope with a flexible blade, a handle and a lever, allowing gradual flexion over the distal half of the blade. In this study, we aimed to compare cervical vertebral movements during tracheal intubation with the Flexiblade and Macintosh laryngoscope in 32 patients undergoing elective surgery requiring general anaesthesia (n = 16 per group). Fluoroscopic images of cervical movement were captured before, during and after intubation and evaluated by a radiologist. ⋯ C2-C3 cervical movement was similar in both groups (p = 0.81). No significant differences were noted in success rates for intubation, oxygen saturation levels, haemodynamic variables or intubation-related injury. The decreased extension angle between C1-C2 during Flexiblade laryngoscopy compared with Macintosh laryngoscopy may be an advantage where neurological damage with cervical movement is a concern.