SUMMARY Background

SummaryA 31-year-old female with no risk factors for cardiac disease suffered a peri-operative myocardial infarction during an elective gynaecological procedure under spinal anaesthesia. The timing and nature of cardiac symptoms suggest that the myocardial infarction was caused by coronary artery vasospasm secondary to ephedrine and ⁄ or metaraminol, which were administered to treat spinalinduced hypotension. We review the recent literature and case reports on myocardial infarction attributed to sympathomimetic drugs, and recommend the use of sublingual or intravenous nitrates when signs or symptoms of coronary arterial vasospasm become evident during their use. Spinal anaesthesia is associated with cardiovascular complications, most notably hypotension and bradycardia [1], which often necessitate the use of sympathomimetic drugs such as ephedrine and metaraminol. These agents can cause coronary artery vasospasm, which is thought to be due to their action on alpha-adrenergic receptors on large epicardial arteries [2]. There have been several case reports of myocardial injury as a result of such vasospasm [3][4][5][6]. We describe a case of myocardial infarction in a fit, healthy woman, the signs and symptoms of which were closely temporally related to the administration of ephedrine and metaraminol for spinal-induced hypotension. Case reportA 31-year-old female with a history of stress incontinence was scheduled for an elective tension-free vaginal tape (TVT) procedure under spinal anaesthesia. She had previously received epidural analgesia, with no complications, for two normal vaginal deliveries. She had no history of cardiovascular disease and no risk factors. There was no history of illicit drug use. She was fit and healthy and regularly cycled 20 miles.Prior to insertion of the spinal anaesthetic, she was given 1 l of Hartmann's solution intravenously. She was very anxious about the procedure and so was given intravenous midazolam 2 mg in 1-mg increments. Blood pressure was recorded as 120 ⁄ 72 mmHg and heart rate 74 beats.min )1 . Spinal anaesthesia was induced with 2.7 ml hyperbaric bupivacaine 0.5%. Ten minutes after induction of anaesthesia, her blood pressure fell to 105 ⁄ 65 mmHg and her heart rate to 60 beats.min. She complained of feeling faint and became pale. She was treated with intravenous ephedrine 5 mg, followed by intravenous metaraminol 1 mg. Her blood pressure rose to 180 ⁄ 120 mmHg and she developed a sinus tachycardia of 120 beats.min )1 with frequent ventricular ectopic beats. This was associated with chest tightness and anxiety. She was given a further 2 mg intravenous midazolam in 1-mg increments. After 5 min, her chest discomfort had resolved and the procedure was completed without further complication or significant blood loss. She was transferred to the recovery room.

The First World War was a time of great change for many areas of military medicine. This article reviews some of the particular challenges faced by British Ophthalmic Services during 1914-18.

Iron homeostasis is required to maintain normal physiological processes such as oxygen delivery, DNA synthesis, and enzymatic reactions. An overall disturbance of iron homeostasis, e.g. systemic iron deficiency, was reported in obese subjects. The objective of this study was to examine tissue iron distribution in the dietary‐induced obese mice. Thirty male C57BL/6J mice were randomly assigned into six dietary treatment groups with various levels of iron (control, high and low) and fat (control and high) for 24 weeks. At the end of 24 weeks, tissues including liver, brain, heart, spleen and kidney were harvested and embedded in paraffin. Tissues were then processed and stained for iron using the Prussian blue reaction. Images were recorded using the Motic BA310 compound light microscope at 1000x magnification. Results showed that brain and spleen were the most responsive organs to dietary fat and iron treatments. In both brain and spleen, iron deposits were observed in high iron groups at both control and high fat levels. In the brain, iron deposits were surprisingly observed in mice treated with high fat low iron diet, indicating the vulnerability of brain to possible iron‐induced oxidative stress. To further evaluate overall brain iron disturbance by high fat diet, the expression of iron‐related proteins (storage, transport, and export proteins) and oxidative stress markers will be measured.

Cricoid pressure is used to reduce the risk of aspiration during rapid sequence induction. The recommended force applied to the cricoid is 10-20 newtons (N; 1.020-1.040 kg) on awake patients and 30-40N (3.060-4.080 kg) on anaesthetised patients. However clinically, it is difficult to estimate the required force. We assessed the effectiveness of 3 recommended teaching methods on the ability to apply the correct force using an airway model that simulated "awake" and "anaesthetised" patients. Thirty nurses and doctors from two hospitals and with clinical experience applying cricoid pressure were included. Measurements of baseline force for "awake" and "anaesthetised" patients were obtained from all participants using measuring scales. Participants were blinded to the force applied. Participants were taught one of three different techniques: biofeedback, nose and syringe. Post-teaching, blinded force measurements were repeated. Data analysis was performed using a linear mixed model and marginal prediction models of applied force reported. For "awake" patients, nose method forces were within the recommended range (mean 14.6N, 95%CI 9.7-19.4). The biofeedback method led to predicted forces at the upper limit of recommended (21.6N, and the syringe method forces were greater than recommended (29.0N, 95%CI 23.9-34.0). For "anaesthetised" patients, nose method forces were less than recommended (26.3N, 95%CI 21.6-31.1), the biofeedback method led to predicted forces within range (33.4N, 28.4-38.3) and syringe method forces were above those recommended (40. 8N,). The biofeedback technique is the most effective method for teaching the application of recommended cricoid pressure force for both awake and anaesthetised patients.

Meprins, metalloproteases that are abundantly expressed in the brush border membranes of proximal kidney tubules, have been implicated in urinary tract infections (UTIs) and diabetic nephropathy. Women with UTIs have been shown to have high levels of meprin A in their urine. This study evaluated for the presence of uropathic bacteria in the urine of two strains of mice, C57BL/6 (n=17) and C3H/He (n=14), with normal and deficient levels of meprin A respectively. Streptozotocin (STZ) was used to induce type 1 diabetes in 8 week old female mice. Urine samples were collected at 8 weeks post‐STZ injection, and population differences in bacteria were surveyed through differential media (CHROMagar Orientation). Both the overall quantity and the range of different types of uropathic bacteria were significant in response to the interacting effect of meprin A and diabetes status (two‐way ANOVA, P<0.05). For the C3H/He group, there was an increase of 20% to 40% of specimens reporting more than one variety of uropathic bacteria from control to diabetes, and for the C57BL/6 group, 0% to 30%. These results indicate that diabetes and levels of meprin A affect variety and quantity of bacteria in the urinary bladder.