None.

Alternating tangential flow (ATF) filtration has been used with success in the Biopharmaceutical industry as a lower shear technology for cell retention with perfusion cultures. The ATF system is different than tangential flow filtration; however, in that reverse flow is used once per cycle as a means to minimize fouling. Few studies have been reported in the literature that evaluates ATF and how key system variables affect the rate at which ATF filters foul. In this study, an experimental setup was devised that allowed for determination of the time it took for fouling to occur for given mammalian (PER.C6) cell culture cell densities and viabilities as permeate flow rate and antifoam concentration was varied. The experimental results indicate, in accordance with D'Arcy's law, that the average resistance to permeate flow (across a cycle of operation) increases as biological material deposits on the membrane. Scanning electron microscope images of the post-run filtration surface indicated that both cells and antifoam micelles deposit on the membrane. A unique mathematical model, based on the assumption that fouling was due to pore blockage from the cells and micelles in combination, was devised that allowed for estimation of sticking factors for the cells and the micelles on the membrane. This model was then used to accurately predict the increase in transmembane pressure during constant flux operation for an ATF cartridge used for perfusion cell culture.

Successful thoracotomy in the prehospital environment is becoming more widely accepted.1 2 Here we present the case of cardiac arrest secondary to penetrating chest injury and the successful prehospital thoracotomy that followed. The resuscitation was associated with the spontaneous return of motor activity and later, hospital discharge. The implication for the immediate need for anaesthesia and paralysis is discussed together with a description of the surgical technique. CASE REPORTA teenage male youth sustained a stab wound to the left chest, in the third intercostal space at the junction of the medial and middle thirds of the clavicle. This wound was part of a deliberate self harm attempt. On arrival of the medical team-15 minutes from 999 call-he was thrashing and taking a few agonal breaths, this rapidly deteriorated to cardiac arrest within the first few seconds of assessment.The patient was placed on the floor of his first floor flat and endotracheal intubation was undertaken by the medical team paramedic; cannulation was achieved by a first responder paramedic and the medical team doctor undertook bilateral thoracostomies in the right and left 4th intercostal space, midaxillary line. This revealed a small haemothorax on the left side. The thoracostomies were joined by a skin incision using a 22 blade scalpel through skin and subcutaneous fat. Heavy duty shears were placed through the thoracostomy and used to cut through muscle and sternum thus making a large clamshell thoracotomy.With the chest open the pericardium was visualised as a blue, tense sac. Mosquito forceps were used to tent the pericardium and it was incised with scissors and widely opened. A large clot was removed and the operator's right index finger used to occlude a hole in the posterior aspect of the left upper heart. As the hole was occluded the heart began to fill and beat, restoring a carotid pulse. There was no anterior wound.The patient attempted to breathe and then localised both upper limbs towards the chest incision. He was rapidly sedated and paralysed with midazolam 10 mg and pancuronium 8 mg. The patient was then lifted down two flights of stairs and taken to the nearest accident and emergency/cardiothoracic centre still with digital occlusion of the hole. Treatment at scene lasted 18 minutes. Bleeding from the internal mammary vessels was controlled with mosquito forceps.On arrival, (journey time four minutes) he was maintaining a heart rate of 100 beats per minute and a systolic blood pressure of between 60 and 90 mm Hg. A cardiothoracic response enabled haemostatic sutures to be placed while in the resuscitation room before transfer to theatre for definitive closure. He was then transferred to the intensive care unit.The postoperative course was initially difficult requiring a second thoracotomy for intrathoracic bleeding. Sepsis caused a syndrome of renal failure requiring haemofiltration. However by day eight he was alert and appropriate neurologically, requiring no cardiovascular support and doing well. Subsequently he m...

Carotid endarterectomy may be performed satisfactorily during superficial or deep cervical plexus block placement with no differences in terms of supplemental local anesthetic requirements, although this is influenced by whether paresthesia is elicited during placement of the deep block. Therefore, the clinician's decision to use one block rather than another need not be based on any assumed superiority of one block based on intraoperative conditions or patient satisfaction.

† The authors review the use of regional anaesthesia in carotid endarterectomy. † They note the reduced hospital stay, but the similar rate of stroke, compared with general anaesthesia. † Methods of achieving regional anaesthesia are detailed, and the authors note the improvements in the equipment available. Summary. Regional anaesthesia is a popular choice for patients undergoing carotid endarterectomy (CEA). Neurological function is easily assessed during carotid crossclamping; haemodynamic control is predictable; and hospital stay is consistently shorter compared with general anaesthesia (GA). Despite these purported benefits, mortality and stroke rates associated with CEA remain around 5% for both regional anaesthesia and GA. Regional anaesthetic techniques for CEA have improved with improved methods of location of peripheral nerves including nerve stimulators and ultrasound together with a modification in the classification of cervical plexus blocks. There have also been improvements in local anaesthetic, sedative, and arterial pressure-controlling drugs in patients undergoing CEA, together with advances in the management of patients who develop neurological deficit after carotid cross-clamping. In the UK, published national guidelines now require the time between the patient's presenting neurological event and definitive treatment to 1 week or less. This has implications for the ability of vascular centres to provide specialized vascular anaesthetists familiar with regional anaesthetic techniques for CEA. Providing effective regional anaesthesia for CEA is an important component in the armamentarium of techniques for the vascular anaesthetist in 2014.