Effect of ferrous ion concentration on the kinetics of radiation-induced iron-oxide nanoparticle formation and growth.

Magnetite nanoparticles were formed by γ-radiolysis of solutions containing different initial concentrations of FeSO4 without any other chemical additives. The particles formed in a given [Fe2+]0 had a narrow size distribution and the average size increased with [Fe2+]0. Five hour irradiation at 0.8 Gy s-1 produced an average size ranging from 23 ± 2 nm to 300 ± 40 nm in 0.1 mM or 10 mM [Fe2+]0 solutions, respectively. To ascertain the size-determining mechanism, the kinetics of γ-radiation-induced particle formation and growth were investigated by simultaneously analyzing the [H2(g)] in the headspace, the [FeII] and [FeIII] dispersed in solution, UV-Vis absorbances at 304 nm and 380 nm, and the pH of the solution. The particles formed were characterized by TEM imaging and various spectroscopic analyses. For a given [Fe2+]0 the time-dependent behaviours of different analyses collectively show three distinct kinetic stages of iron oxidation. The [Fe2+]0 affects the oxidation kinetics of different stages and hence, the oxidation yields and the size of particles formed after irradiation. The main processes which cause the observed kinetics and yields in the three stages are proposed.

The accuracy of reporting of general anaesthesia for childbirth: a validation study.

Administrative population health data, such as hospital discharge data, are a potentially valuable resource for determining anaesthesia and analgesia use in childbirth at a population level. However the reliability of general anaesthesia reporting is unknown. This study aimed to determine the accuracy of the reporting of peripartum general anaesthesia in single and linked population health data. Data from a statewide validation study of 1200 women provided the gold standard for delivery and postpartum general anaesthesia use. The validation data were merged with both the hospital discharge and birth databases. As both of these datasets collect information on general anaesthesia, it could be reported in one, both or neither database. Among the 1184 records available for review, 7.7% of women had a general anaesthetic during the birth admission, of which 6.2% were for delivery and 1.5% were for a postpartum procedure. Reporting sensitivities ranged from 26% to 97% and specificities 94% to 100%. Identifying general anaesthesia from either the birth or hospital data improved general anaesthesia ascertainment. Limiting analysis to caesarean sections resulted in very accurate identification of general anaesthesia for delivery (sensitivity 97.0%, specificity 99.8%) while limiting to vaginal births was moderately accurate for identifying postpartum general anaesthesia (sensitivity 73.2%, specificity 99.8%). General anaesthesia for delivery is reported with a high level of accuracy in birth and linked birth-hospital data, but not in hospital discharge data alone. Population health data are a reliable source for examining general anaesthesia for delivery.

Inguinal field block for adult inguinal hernia repair using a short-bevel needle. Description and clinical experience in Solomon Islands and an Australian teaching hospital.

One of the limitations of an inguinal field block is that it does not reliably produce complete anaesthesia. The purpose of this study was to describe a modified short-bevel needle technique, facilitating correct needle placement, for inguinal hernia repair. Anaesthetists from two different institutions performed the described infiltration blocks. Prospective data were collected from these groups, each having 30 patients. We evaluated the safety and reliability of the described block. Of the 60 patients, two were "failed" blocks, requiring conversion to general anaesthesia. There were no other major intraoperative or recovery room complications. Results of the modified inguinal field block showed a 97% ability to achieve a "fair" block or better. Intraoperative and postoperative data showed high surgeon and patient satisfaction for the block. The described block using a short-bevel needle is recommended as a suitable method for adult patients undergoing inguinal hernia repair.

Spinal anaesthesia for caesarean section in the Solomon Islands.

Results were kept on 43 spinal anaesthetics performed for caesarean section in the Solomon Islands, a developing tropical country in the Pacific Ocean. A 25-gauge Quincke needle was used and either 2.5 ml of heavy bupivacaine 0.5% or 2.0-2.5 ml of plain bupivacaine 0.5% were injected. Hypotension down to 85 mmHg occurred in four patients and there were no spinal headaches. Five patients had to be given a general anaesthetic. We recommend this technique to other doctors working in the Pacific Islands.

Selective block of nerves in the axillary approach to the brachial plexus.

BACKGROUND AND OBJECTIVE: Optimal surgical conditions for flexor tendon tenolysis in the hand were achieved by ulnar, radial, and musculocutaneous nerve block at the axilla combined with median nerve block at the wrist. RESULT: Because the median nerve function proximal to the wrist was preserved, the patient was able to flex the finger intraoperatively. CONCLUSION: Palpation of nerves together with a nerve stimulator were used to localize the nerves accurately.

Shoulder manipulation to facilitate central vein catheterization from the external jugular vein.

Manipulation of the shoulder to facilitate passage of J-wires past the clavicle during external jugular vein catheterization was tested prospectively in 111 adult patients undergoing cardiac surgery. On 10 of 25 occasions when the wire would not pass into the thorax, manipulation of the shoulder then allowed the wire to pass.

Foot surgery in Vanuatu: results of combined tibial, common peroneal and saphenous nerve blocks in fifty-six adults.

Combined tibial and common peroneal nerve anaesthesia was used for foot and ankle surgery in fifty-six adults. Where necessary, the saphenous nerve was also blocked. A calibrated constant current nerve stimulator was used to localise the nerves in the popliteal fossa. Using lignocaine 1%, an opioid premedication, but no other sedation or top-up injection, 60% of the blocks were successful. If a patient felt pain at incision or during surgery, the block was recorded as a failure.