A simple tissue model for practicing ultrasound guided vascular cannulation.

INTRODUCTION: The use of ultrasound in anaesthetic practice continues to be more established and the use of ultrasound guidance in establishing vascular access is recommended by various groups. We have developed a tissue model for the practice and skills development in ultrasound vascular access. METHOD: The tissue model consist of a piece of "pork belly", a longitudinal shaped balloon inserted between two muscle layers at a chosen depth of the tissue model (mimics a blood vessel), a bag of intravenous fluid (e.g. Ringer's Lactate) together with a giving set and a short piece of extension tubing connected to a three-way tap used to expel air from the system. One end of the balloon is tied to the giving set with the intravenous fluid. The other end is tied to the short tubing with the three-way tap. RESULTS: Ultrasound images of the fluid filled balloon mimic a blood vessel. It is possible under ultrasound guidance to puncture the balloon several times (>10times) and still be able to distend the balloon with fluid. INTERPRETATION: Ultrasound guided techniques require practice to improve hand-eye coordination. The "pork belly" tissue model allows multiple needle puncture without losing its functional integrity. CONCLUSION: We believe the "pork belly" tissue model adds to the range of models that can be used to practice ultrasound guided vascular access. The components required for this model are readily available locally and affordable.

Cuff inflation to aid nasotracheal intubation using the C-MAC videolaryngoscope.

A preliminary report is presented of a technique for using the C-MAC videolaryngoscope to carry out nasopharyngeal intubations. The main thrust of the technique is that cuff inflation of the endotracheal tube is used to lift the endotracheal tube off the posterior pharyngeal wall and thus direct it towards the glottis. The technique was used successfully in 5 consecutive patients needing nasotracheal intubation. Indeed a couple of these patients might have been difficult to intubate using conventional laryngoscopy. The full technique is described together with pictures at the various stages of intubation.

Porcine anaesthesia for advanced trauma operative management (atom).

Anaesthesia has been provided for pigs for the Advanced Trauma Operative Management Course which was first held at the Korle Bu Teaching Hospital in February 2005. As of January 2006, 16 animals have been anaesthetized. Acepromazine (1mg/kg) and atropine (0.05mg/kg) were used for premedication. IM ketamine (30mg/kg) and isoflurane (in oxygen) were used for the anaesthesia and the animals were intubated and ventilated with positive pressure ventilation. No neuromuscular blocking agents were used. Morphine (average 3 doses of 10mg) was used for analgesia. Systolic blood pressure ranged between 80mmHg and 115mmHg and diastolic pressure ranged between 45mmHg and 80mmHg. Large amounts of IV fluids were given during the procedure. At the end of surgery, the animals were euthanized by increasing the concentration of isoflurane and administering potassium chloride. Out of the 14 cases reported on, 13 animals survived to the end of all the surgical procedures. 1 animal had a cardiac arrest during the last procedure (inflicting a laceration to the heart) and could not be resuscitated.

Surgically correctable adrenal-dependent hypertension: a report of five cases.

SummaryAlthough endocrine causes of secondary hypertension are relatively uncommon, medical practitioners must maintain a high index of suspicion for them in certain categories of patients. Such patients include young individuals, those with difficult-to-treat hypertension and those presenting with symptoms, clinical signs and/or laboratory parameters well-known to be associated with Cushing's syndrome, Conn's syndrome or phaeochromocytoma.This paper reports on 5 patients identified over a 2-year period with various hormonally-active adrenal adenomas causing hypertension in an environment where, hitherto, the occurrence of these conditions was generally thought to be rare. Aspects of the patients' histories, examination and laboratory findings that drew attention to the possibility of the diagnosis in each case are highlighted, as are the confirmatory investigations and management methods used by a multidisciplinary team of medical practitioners. The clinical outcome with appropriate treatment of adrenal-related hypertension is good and can result in significant cost savings in the long term.

Rupture of sinus of Valsalva aneurysm: case report.

Sinus of Valsalva aneurysms are uncommon. Aortic sinus aneurysm may be complicated by endocarditis or rupture. A 26 year old native Ghanaian presented with dyspnoea, raised jugular venous pressure (JVP), tender hepatomegaly, peripheral oedema, a thrill and a continuous murmur at the upper left sternal edge. Two-dimensional doppler echocardiography with colour flow mapping revealed a large aneurysm of the right sinus of Valsalva (4 cm diameter) that abutted the right ventricular out-flow tract with distortion of the pulmonary valve. Colour flow revealed left to right shunting of blood from the aortic root into the right atrium. A year later he presented with a febrile illness, weight loss, night sweats and was diagnosed as having culture negative infective endocarditis. Following a course of antibiotics, he underwent successful cardiopulmonary bypass surgery with repair of the ruptured aneurysm of the right sinus of Valsalva.

Remifentanil and pulmonary extraction during and after cardiac anesthesia.

We measured the apparent blood clearance and pulmonary extraction ratio of remifentanil in 10 adult patients undergoing elective myocardial revascularization for the first time with hypothermic cardiopulmonary bypass (CPB). Patients received continuous infusions of remifentanil 1.0, 1.5 or 2.0 microg x kg(-1) x min(-1). After surgery, remifentanil was infused at 1.0 microg x kg(-1) x min(-1) in all patients. Remifentanil concentrations were measured in pulmonary and radial artery blood by gas chromatography with high resolution mass spectrometry before and after CPB and 165 min (60 SD) after surgery. Cardiac output was measured by thermodilution at the time of blood sampling. The mean pulmonary extraction ratio of remifentanil was 5.7% (13.1% SD), which was not significantly different from zero. However, pulmonary extraction ratio was related inversely to the pulmonary artery hydrogen ion concentration and directly to the percent of nonionized form of the base in the pulmonary artery. Remifentanil concentrations in pulmonary and radial artery blood were related directly to infusion rate, but not to duration of infusion. There was no evidence of accumulation or sequestration. Mean apparent blood remifentanil clearance was 2.03 L/min (0.35 SD) and, in contrast to remifentanil pulmonary extraction ratio, was related directly to cardiac index and oxygen delivery. Increased tissue perfusion increased blood remifentanil clearance. We found predictable blood remifentanil levels with no evidence of accumulation or pulmonary extraction.

The anaesthetic management of a case of phaeochromocytoma

The anaesthetic management of a case of phaeochromocytoma is presented. It is pointed out that the number of cases in our environment may be higher than we think and that a high index of suspicion is necessary to pick out cases of phaeochromocytoma from the population of hypertensive patients. In our setting it is often difficult getting the necessary drugs to manage cases of phaeochromocytoma. Limited monitoring equipment may also be a handicap. It is however; pointed out that with attention to care and detail; cases of phaeochromocytoma can be successfully managed in our environment