Transcranial Doppler (TCD) is a noninvasive ultrasound (US) study used to measure cerebral blood flow velocity (CBF-V) in the major intracranial arteries. It involves use of low-frequency (≤2 MHz) US waves to insonate the basal cerebral arteries through relatively thin bone windows. TCD allows dynamic monitoring of CBF-V and vessel pulsatility, with a high temporal resolution. It is relatively inexpensive, repeatable, and portable. However, the performance of TCD is highly operator dependent and can be difficult, with approximately 10–20% of patients having inadequate transtemporal acoustic windows. Current applications of TCD include vasospasm in sickle cell disease, subarachnoid haemorrhage (SAH), and intra- and extracranial arterial stenosis and occlusion. TCD is also used in brain stem death, head injury, raised intracranial pressure (ICP), intraoperative monitoring, cerebral microembolism, and autoregulatory testing.

A best evidence topic was written according to a structured protocol. The question addressed was whether cryoanalgesia improves post-thoracotomy pain and recovery. Twelve articles were identified that provided the best evidence to answer the question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were pain scores, additional opiate requirements, incidence of hypoesthesia and change in lung function. Half of the articles reviewed failed to demonstrate superiority of cryoanalgesia over other pain relief methods; however, additional opiate requirements were reduced in patients receiving cryoanalgesia. Change in lung function postoperatively was equivocal. Cryoanalgesia potentiated the incidence of postoperative neuropathic pain. Further analysis of the source of cryoanalgesia, duration, temperature obtained and extent of blockade revealed numerous discrepancies. Three studies utilized CO2 as the source of cryoanalgesia and four used nitrous oxide, but at differing temperatures and duration. Five studies did not reveal the source of cyroanalgesia. The number of intercostal nerves anaesthetized in each study varied. Seven articles anaesthetized three intercostal nerves, three articles used five intercostal nerves, one article used four intercostal nerves and one used one intercostal nerve at the thoracotomy site. Thoracotomy closure and site of area of chest drain insertion may have a role in postoperative pain; but only one article explained method of closure, and two articles mentioned placement of chest drain through blocked dermatomes. No causal inferences can be made by the above results as they are not directly comparable due to confounding variables between studies. Currently, the evidence does not support the use of cryoanalgesia alone as an effective method for relieving post-thoracotomy pain.

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'Is porcine or bovine valve better for aortic valve replacement?' Altogether, 562 papers were found using the reported search, of which 15 represented the best evidence to answer the question. All papers represent either level 1 or 2 evidence. The authors, journal, date, country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This best evidence paper includes 9880 patients from 1974-2006 to compare both valve types. All studies compared either all or some of the following outcomes: complication, durability, mortality, functional status and haemodynamic function. Ten of 15 papers assessed the complication profile due to aortic valve replacement in both valve types. Four papers concluded that bovine valves are superior, whereas only one favoured porcine valves. Five papers showed a similar complication profile between both valves. Six of 15 papers commented on valve durability. Both porcine and bovine valve groups have two papers each to support their superiority in valve durability. Two papers demonstrated similar durability in both valves. There are 11 papers comparing the postoperative mortality. We suggest that there is no difference in mortality profile as eight papers showed that both valves had similar mortality profiles. Two papers supported bovine valve and one paper supported porcine valve in this aspect. There were four papers assessing the postoperative functional status, with three papers suggesting that both valve types had similar clinical improvement postoperatively. Eleven papers compared the haemodynamic function. Nine papers were in favour of bovine valves. Two papers demonstrated similar haemodynamic profiles in both valves. In conclusion, the bovine valve is superior in its complication and haemodynamic profiles. Both bovine and porcine valves have comparable results with regard to the mortality, postoperative functional status and valve durability. Significant variability between the valve manufacturers, study designs, study period and patient population in the above studies impose limitations to the comparison of both valves.

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The authors report a rare case of 17-year-old lady with late presentation of congenital diaphragmatic hernia. She presented with vague abdominal pain and was thought to have urinary tract infection, ruptured ovarian cyst, and appendicitis by different medical teams in the first few days. She eventually underwent a diagnostic laparoscopy with no significant findings. In the early postoperative recovery period, she suffered from severe cardiorespiratory distress and a large intestinal left diaphragmatic hernia was diagnosed subsequently. At further operation a strangulated loop of large bowel herniating through a left antero-lateral congenital diaphragmatic hernia was discovered, which was reduced and repaired with a prolene mesh through thoracotomy. She made an excellent recovery and was discharged a few days after the operation. The authors postulate a mechanism of positive pressure from laparoscopic surgery causing herniation of large bowel through a pre-existing diaphragmatic defect. This case highlights the diagnostic challenge of this disease due to its diverse clinical presentation, the importance of prompt diagnosis and intervention.

A best evidence topic was written according to a structured protocol. The question addressed was whether dissection of the pulmonary ligament during an upper lobectomy would result in improved outcomes. A total of 85 articles were found using the reported search, of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were complications associated with dissection (atelectasis, bronchial stenosis, bronchial obstruction and bronchial deformation) and preservation (insufficient lung expansion, pooling of effusion and atelectasis) of the pulmonary ligament, ratio (%) of dead space in longitudinal axis (movement of nonoperated lobes), change in the angle (degrees) of main bronchus on the operated side, overall morbidity and mortality, overall survival and conversion rates. In a randomized control trial, the dissection of the pulmonary ligament revealed no significant difference in the dead space ratio or change in the angle of the main bronchus when compared with preservation. Dissection of the ligament, in theory, reduces the free space in the upper thorax by increasing the mobility of the residual lobes. Dissection of the ligament may lead to bronchial deformation, stenosis, obstruction or lobar torsion. Preservation of the ligament may prevent this complication by suppressing the upward movement of residual lobes. However, this may result in pleural effusion in the free thoracic space that may potentially become infected resulting in an empyema or bronchial fistula. Five large case series were analysed; three routinely dissected the pulmonary ligament and two did not. There was no observed difference in clinical outcomes between the two groups. There is no convincing evidence that dissection of the pulmonary ligament in an upper lobectomy significantly improves outcomes and reduces complications.

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Is it possible to predict the risk of ischaemic bowel after cardiac surgery?' Altogether 80 papers were found as a result of the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This best evidence topic presents 68 214 cardiac surgical patients from seven major cardiothoracic centres dated from 1980 to 2011. The incidence and mortality rates of bowel ischaemia after cardiac surgery range from 0.07-0.5 and 59-64%, respectively. Advanced age and peripheral vascular disease are the common preoperative risk factors, which were reported by 3 papers each. The most common intraoperative risk factors were prolonged cross-clamp and cardiopulmonary bypass time, which were reported by 3 papers each. Five of 7 papers reported that the use of intra-aortic balloon pump was a significant risk factor. The use of inotropes, postoperative blood loss and postoperative renal failure were reported by 3 of 7 papers, each to be a significant risk factor for postoperative bowel ischaemia in cardiac surgery patients. We, therefore, conclude that these are probably the most significant and useful predictive risk factors for bowel ischaemia after cardiac surgery. Thus, careful intraoperative management to minimize cardiopulmonary bypass and cross-clamp time and optimal care of patients' postoperative haemodynamic status, particularly in elderly patients with severe atherosclerotic disease, are useful in preventing this rare but lethal postoperative complication. Besides that, a heightened clinical suspicion in patients with these risk factors may lead to prompt diagnosis of bowel ischaemia, allowing intervention to prevent mortality. The variability of the study design and risk factors studied in each paper impose limitation to summarize the predicting risk factors.

SUMMARYWe report a case of a 51-year-old male patient with a known history of Carney complex, who was operated on for the fourth time due to recurrent left atrial myxomas. Despite surgical challenge, the operation was uneventful.The patient had a difficult postoperative period and needed further treatment for complications. After a prolonged recovery, he is currently well and remains myxoma-free up until now (36 months postsurgery) with regular follow-up using cardiac CT and transthoracic echocardiogram. BACKGROUND