Prevalence and risk factors of chronic post-thoracotomy pain in Chinese patients from Peking Union Medical College Hospital

Background In clinical practice, the mechanisms underlying chronic post-surgical pain （CPSP） remain insufficiently understood. The primary goals of this study were to determine the incidence of chronic pain after thoracic surgery and to identify possible risk factors associated with the development of chronic post-thoracotomy pain in Chinese patients. The secondary goal was to determine whether the difference between pre- and post-operative white blood cell （WBC） counts could predict the prevalence of CPSP after thoracotomy. The impact of chronic pain on daily life was also investigated. Methods We contacted by phone 607 patients who had undergone thoracotomy at our hospital during the period February 2009 to May 2010. Statistical comparisons were made between patients with or without CPSP. Results Results were ultimately analyzed from 466 qualified patients. The overall incidence of CPSP was 64.5%. Difference between pre- and post-operative WBC counts differed significantly between patients with or without CPSP （P 〈0.001） and was considered as an independent risk factor for the development of CPSP following thoracotomy （P 〈0.001）. Other predictive factors for chronic pain included younger age （〈60 years, P 〈0.001）, diabetes mellitus （P=0.023）, acute post-operative pain （P=0.005） and the duration of chest tube drainage （P 〈0.001）. At the time of interviews, the pain resulted in at least moderate restriction of daily activities in 15% of the patients, of which only 16 patients had paid a visit to the doctor and only three of them were satisfied with the therapeutic effects, Conclusions Chronic pain is common after thoracotomy. WBC count may be a new independent risk factoring surgical patients during peri-operative period. Besides, age, diabetes mellitus, acute post-operative pain, and duration of chest tube drainage may also play a role in chronic post-surgical pain occurrence.

Postoperative neuropsychological change and its underlying mechanism in patients undergoing coronary artery bypass grafting

Background The high incidence of neuropsychologic deficits after cardiac surgery, including cognitive dysfunction and mood status, has significantly influenced the prognosis, outcome of treatment and long-term quality of life of patients. With a circadian secretion pattern, melatonin and cortisol are capable of modulating the human physiological processes and neuropsychological status, whereas disorder of their secretion pattern may lead to many diseases. However, it is unclear whether neuroendocrine variations are related to the neuropsychologic status in patients undergoing coronary artery bypass grafting （CABG）. Methods Forty male patients scheduled for CABG with hypothermic cardiopulmonary bypass （CPB） （n=20） or off-pump coronary artery bypass （OPCAB） （n=20） were studied. Blood samples were taken intraoperatively at specific time-points and every 3 hours within the first postoperative 24 hours to determine plasma concentrations of melatonin and cortisol. A neuropsychologic test battery including depression and anxiety was administered preoperatively and 7 to 10 days postoperatively. Statistical methods included the nonparametric analysis, multiple linear regression and cosinor analysis. Results The patients in the CPB group exhibited more severe neuropsychologic deficits and more anxious than those in the OPCAB group after surgery. In both groups, patients were more depressed postoperatively than preoperatively and recovered 3 months after surgery. Depression and anxiety were correlated with some factors of cognitive dysfunctions. In the postoperative 24 hours, 2 patients in the CPB group, and 6 patients in the OPCAB group showed a circadian rhythm of melatonin secretion. As for cortisol secretion, there were 3 patients in the CPB group and 7 in the OPCAB group respectively. Parameters of circadian rhythm of melatonin in the CPB group and those of secretion rhythm of cortisol in both groups were correlated with depression and some neuropsychologic tests. Conclusions The incidence of neuropsychological deficits was higher in patients receiving CABG with CPB than in those without CPB. The status of mood may contribute to the perioperative cognitive dysfunctions. The disordered circadian rhythm of melatonin secretion in patients undergoing CABG with CPB and the disordered cortisol secretion may correlate directly or indirectly through mood with neuropsychological deficits.

Clinical features and diagnosis for Chinese cases with malignant hyperthermia： a case cluster from 2005 to 2007

Background Malignant hyperthermia （MH）, manifesting as MH crisis during and/or after general anesthesia, is a potentially fatal disorder in response to volatile anesthetics and depolarizing muscle relaxants. Though typical features of MH episode can provide clues for clinical diagnosis, MH susceptibility is confirmed by in vitro caffeine-halothane contracture test （CHCT） in western countries. It is traditionally thought that MH has less incidence and fewer typical characteristics in Chinese population than their western counterparts because of the different genetic background. In this study, we investigated the clinical features of MH in Chinese cases and applied the clinical grading scale and CHCT for diagnosis of MH. Methods A cluster of three patients with MH, from January 2005 to December 2007, were included in the study. Common clinical presentations and the results of some lab examinations were reported in detail. The method of the clinical grading scale of diagnosis of MH was applied to estimate the qualitative likelihood of MH and predict MH susceptibility. Muscle fibers of femoral quadriceps of the patients were collected and CHCT was performed to confirm the diagnosis of MH. Results The clinical grading scales of diagnosis of the disease for these cases were all ranked grade D6, suggesting almost diagnosed ones. And the results of caffeine test were positive correspondingly, indicating that the patients should be diagnosed as MH susceptibility （MHS） according to diagnostic criteria of the North America MH group, which were already confirmed by clinical presentations and biochemical results. Conclusions These Chinese cases manifest as MH crisis. The clinical grading scale of diagnosis of MH may provide clues for clinical diagnosis. CHCT can also be used in confirming diagnosis of MH in Chinese cases though they have different genetic background from their western counterparts.

Circadian rhythm:a new clue for neuropsychological dysfunction after cardiac surgery

In the recent editorial comment, DubouleI emphasized .that ＂animal development is, in fact, nothing but time＂.That a circadian timing system is apparently universal in biology is the evidence for the important physiological role that rhythmicity plays. It is by the circadian rhythm that we could choose the optimal time to give therapeutic settings, such as antihypertensive drugs, adjusting sleep disorders and hormone in order to improve the prognosis. Besides the physiological action, there is pathological significance for circadian rhythm. In the recent years, more and more evidences have been found that the mechanisms of many diseases are associated with rhythm disturbance.