Substance use disorder in the anaesthetist: Guidelines from the Association of Anaesthetists: Guidelines from the Association of Anaesthetists.

Anaesthetists have a higher incidence of substance use disorder when compared with other doctors. This might be due to the ease of access to intravenous opioids, propofol, midazolam, inhalational agents and other anaesthetic drugs. Alcohol use disorder continues to be the most common problem. Unfortunately, the first sign that something is amiss might be the anaesthetist's death from an accidental or deliberate overdose. While there are few accurate data, suicide is presumed to be the cause of death in approximately 6-10% of all anaesthetists. If we are to prevent this, substance use disorder must be recognised early, we should ensure the anaesthetist is supported by their department and hospital management and that the anaesthetist engages fully with treatment. Over 75% of anaesthetists return to full practice if they co-operate fully with the required treatment and supervision.

Fabrication of a Self-Supported Nanoparticle-Decorated Amphipathic Film at a Liquid/Liquid Interphase.

The design and facile fabrication of an amphipathic, mechanically durable, nanoparticle (NP)-decorated film has been realized at a liquid/liquid interphase. The innovative film is prepared by applying a changing electric field across an organic-aqueous interphase in the presence of 1-2 nm metal NPs, with a specific focus on Ir NPs in this work, self-assembled at the interphase, where the organic phase consists of a dissolved hydrophobic polymer in a volatile solvent. The electrochemical process leads to the oxidation of the Ir to IrOx, forming a hydrous oxide matrix at the interphase. With evaporation of the residual volatile solvent and precipitation of the polymer backbone, an isolable Ir/IrOx-decorated film is realized. The novelty of this technique stems from the ability to fabricate a substrate material in situ around a nanoparticle matrix, as opposed to transferring the matrix onto a substrate. The subsequent film exhibits a hydrophobic and a hydrophilic surface, permitting the film to reside at a water/oil, water/air, or oil/air interphase. The differences in wettability are attributed to the differences in the chemical and physical properties of the two sides of the film. Interestingly, despite both sides of the film exhibiting different wettabilities, both sides are electrochemically accessible. Several potential applications exist for this film, including the separation and collection of oil from water, in biosensors, and as catalyst layers.

An electrochemical lipopolysaccharide sensor based on an immobilized Toll-Like Receptor-4.

Infections affect millions of people each year and yet methods to ascertain their cause can take more than 24h to be effective. This delay between the presentation with symptoms and the ability to make an informed decision about treatment can have adverse consequences, including death in severe cases. Additionally, pathogen identification is a concern for public safety amid the growing threat of bioterrorism. Developing a detection system based on the immune system offers the advantage of broad specificity, while still remaining pertinent to human health. In this work, human Toll-Like Receptor-4 (TLR-4), a protein responsible for detecting lipopolysaccharide (LPS) of Gram-negative bacteria, was immobilized on both a large area and micro gold electrode via the tethering interaction of a modified Self-Assembled Monolayer (mSAM). In response to varying concentrations of its target, the protein-electrode combination showed a logarithmically proportional increased resistance to charge transfer from a solution-based redox probe, due to the formation of TLR-4 protein dimers. It also demonstrated excellent sensitivity to trace levels of Gram-negative bacteria, while remaining insensitive to both Gram-positive and viral challenges. Further characterization of our mSAM revealed that maintaining the appropriate receptor orientation on the electrode surface, mimicking TLR-4's role in a cellular context, was essential in producing a responsive sensor.

Randomised controlled trial investigating the influence of intravenous fluid titration using oesophageal Doppler monitoring during bowel surgery.

Oesophageal Doppler monitoring allows non-invasive estimation of stroke volume and cardiac output. We studied the impact of Doppler guided fluid optimisation on haemodynamic parameters, peri-operative morbidity and hospital stay in patients undergoing major bowel surgery. Fifty-seven patients were randomly assigned to Doppler (D) or control (C) groups. All patients received intra-operative fluid therapy at the discretion of the non-investigating anaesthetist. In addition, Group D were given fluid challenges (3 ml x kg(-1)) guided by oesophageal Doppler. Group D received significantly more intra-operative colloid than Group C (mean 28 (SD 16) vs. 19.4 (SD 14.7) ml x kg(-1), p = 0.02). Cardiac output increased significantly for Group D whilst that of controls remained unchanged. The mean difference between the groups in final cardiac output was 0.87 l x min(-1) (95% confidence interval 0.31-1.43 l x min(-1), p = 0.003). Five control patients required postoperative critical care admission. Fluid titration using oesophageal Doppler during bowel surgery can improve haemodynamic parameters and may reduce critical care admissions postoperatively.

Importance of the sampling site for measurement of mixed venous oxygen saturation in shock.

OBJECTIVES: To determine if oxyhemoglobin saturation in blood samples taken from the superior vena cava or right atrium can be substituted for oxyhemoglobin saturation in blood taken from the proximal pulmonary artery (SVO2) in patients in shock. DESIGN: Prospective clinical investigation. SETTING: Mixed surgical/medical intensive care unit in a university hospital. PATIENTS: Thirty consecutive patients in severe circulatory shock who required insertion of a pulmonary artery flotation catheter (PAFC) immediately on intensive care unit admission. All patients fulfilled the criteria described below which were established in advance. MEASUREMENTS AND MAIN RESULTS: Oxyhemoglobin saturation in the superior vena cava, right atrium, and pulmonary artery (SVO2) was measured by cooximetry in consecutive blood samples from each site during initial insertion of the PAFC. The mean standard deviation of values from these sites was similar: 74 +/- 12.5%, 70.+/- 13%, and 71.3 +/- 12.7%, respectively. However, when superior vena cava and right atrial oxyhemoglobin saturations and SvO2 were compared, the ranges and 95% confidence limits were found to be clinically unacceptable. The ranges were -19.3 to 23.1% and -19.7 to 16.7%, respectively, and the 95% confidence limits were -18.4 to 24.2% and -18.6 to +17.3%, respectively. CONCLUSIONS: These wide range differences and confidence limits would lead to large errors if superior vena cava or right atrial oxyhemoglobin saturations were substituted for true mixed venous blood in oxygen transport or pulmonary venous admixture calculations, or if clinical decision making was based on individual results. In patients in shock in whom clinical decisions may be based on the value of mixed venous oxyhemoglobin, oxyhemoglobin saturation is only reliably measured in samples taken from the pulmonary artery.

The effect of pre-induction glycopyrronium on the haemodynamic response of elderly patients to anaesthesia with propofol.

This study investigated whether pretreatment with glycopyrronium can attenuate the hypotension caused by anaesthesia of the elderly with propofol. Twenty elderly patients (77.1 +/- 2.44 years, mean +/- SEM) of ASA physical status 2 or 3 scheduled for elective urological procedures were given glycopyrronium 0 (n = 10) or 5 micrograms.kg-1 (n = 10) in a randomised, double-blind manner, 5 min before induction of anaesthesia with propofol infused at 600 ml.h-1 (average induction dose 1.7 +/- 0.06 mg.kg-1, mean +/- SEM) followed by maintenance with a propofol infusion at 10 mg.kg-1.h-1. Although glycopyrronium significantly increased heart rate (p less than 0.01, ANOVA), the decrease in blood pressure 2 and 5 min after induction was similar in both groups. The study had a power of 80% to detect a 20 mmHg difference in systolic arterial pressure between treatment groups with p less than 0.05.

Peripheral aneurysms.

Between January 1970 and December 1990, 17 cases of peripheral aneurysms were observed in 15 patients. Fourteen patients were male and one patient was female. Age ranged between 4 years and 82 years. From the 17 peripheral aneurysms, 4 were false aneurysms, 9 were true atherosclerotic aneurysms, 2 were mycotic and 2 were true blunt traumatic aneurysms. The false aneurysms were caused by gun shot (one case, common carotid artery); complication of carotid endarterectomy (2 cases); iatrogenic (one case, common femoral artery). The atherosclerotic aneurysms (9 cases) were located in the subclavian artery (one case); superficial femoral artery (2 cases in a single patient); and popliteal artery (5 cases). The mycotic aneurysms (two in one patient) were located in the profunda femoris artery and in the anterior tibial artery. The two traumatic true aneurysms were located in the distal radial artery and in one interdigital artery, respectively. From the 17 peripheral aneurysms, 15 were submitted to surgical treatment, with fairly good results, except for one case of infection and another case of fatal renal insufficiency. Follow-up time ranged from 1 to 18 years.

Axillary-subclavian venous thrombosis.

From 1974 through 1984 six patients with axillary-subclavian venous thrombosis were studied and treated. This disorder represents 1% of the various types of venous thrombosis reported in the literature. Symptoms appeared following effort in four patients, while a cervical rib and a scar bridle after radical mastectomy were identified as the underlying cause in two patients. Ages ranged from 17 to 59 years, with a mean age of 33 and equal sex distribution. None of the six patients had blood clotting defects. The diagnosis was based on clinical evaluation and was confirmed by phlebography. There was edema and functional impairment of the arm in all cases. Pain and venous prominence was found in 83%, rubor of the extremity in 66%, local hyperthermia in 50%, and arterial compression in 33%. Five patients were treated with anticoagulants and bed rest. Surgery was performed in two patients with thoracic outlet syndrome. First rib resection with scalenotomy was performed in one case and cervical rib resection with scalenotomy in the other. After a mean follow-up of 13 months, the results were good in four and average in two patients.

The effect of sufentanil on the cardiovascular responses to tracheal intubation.

The effects of sufentanil 0.5 or 1 microgram/kg, given intravenously after induction of anaesthesia, on the cardiovascular responses to tracheal intubation were examined in a controlled, randomised, double-blind investigation. The control group of patients exhibited significant rises in arterial blood pressure and heart rate for 4 minutes after tracheal intubation. Heart rate exceeded 100 beats/minute and systolic pressure increased by over 20% in every patient. All patients moved or breathed within 10 minutes of the administration of suxamethonium. Sufentanil 0.5 microgram/kg prevented increases in the mean values of heart rate and arterial blood pressure, although increases were observed in five patients. Significant falls in the mean values of heart rate and arterial pressure occurred from 4 minutes after intubation until observations ended 15 minutes after induction of anaesthesia. Two patients moved or breathed during this time, although movement in response to nerve stimulation occurred in all patients 10 minutes after administration of suxamethonium. Sufentanil 1 microgram/kg was effective in suppressing a rise in heart rate or arterial pressure in every patient. Significant falls in these variables occurred from 2 minutes after tracheal intubation onwards. No patient moved or breathed for 15 minutes after induction of anaesthesia, although neuromuscular transmission was present 10 minutes after giving suxamethonium in each case.