Thermal pain tolerance and pain rating in normal subjects: Gender and age effects.

BACKGROUND: Thermal detection thresholds and thermal pain thresholds are important in quantitative sensory testing. Although they have been well studied for assessing somatosensory function, the investigation of thermal pain tolerance has been insufficient. The aim of this study was to explore the characteristics of thermal pain tolerance and pain ratings in healthy subjects. METHODS: Cold pain tolerance (CPTol) and heat pain tolerance (HPTol) were tested in 213 healthy adults aged 18-81 years recruited from the local community. The thermal detection and thermal pain thresholds were also tested to investigate the association with pain tolerance. The visual analogue scale (VAS) was used for assessing pain severity immediately after the thermal pain and tolerance tests. RESULTS: The normality of the CPTol and HPTol was acceptable. Most participants rated the pain induced by the CPTol and HPTol testing as moderate. HPTol was lower in women than in men (p = 0.001), but CPTol did not differ between sexes. The pain ratings of CPTol and HPTol did not differ between sexes, but significant age effects were observed. The association of the tolerance temperature with pain ratings was weak, while those of pain ratings for CPTol and HPTol were strong (r = 0.87). CONCLUSIONS: Women were more sensitive to tolerance heat pain stimuli. Younger participants reported more pain for thermal pain and tolerance tests. SIGNIFICANCE: Thermal pain tolerance and pain rating for the thermal pain tolerance temperature depend on gender and age. Women are more sensitive to heat temperatures, young people rate more pain, and the pain ratings of heat and cold are strongly correlated.

Nasotracheal intubation in patients with limited mouth opening: a comparison between fibreoptic intubation and the Trachway®.

In patients with limited mouth opening, traditional laryngoscopy and videolaryngoscopes are not useful when performing nasotracheal intubation. Eighty patients with limited mouth opening who required nasotracheal intubation were randomly assigned to either fibreoptic intubation (n = 40) or the Trachway(®) (n = 40). Using the modified nasal intubation difficulty scale, 22 (55%) patients who received fibreoptic intubation were categorised as no difficulty compared with 40 (100%) patients in the Trachway group (p < 0.001). Mean (SD) total intubation time was 71.8 (23.3) s in patients who received fibreoptic intubation compared with 35.4 (9.8) s in the Trachway group (p < 0.001). We conclude that the Trachway technique for nasotracheal intubation is quicker and easier compared with fibreoptic intubation in patients with limited mouth opening.

Persistent mechanical allodynia positively correlates with an increase in activated microglia and increased P-p38 mitogen-activated protein kinase activation in streptozotocin-induced diabetic rats.

BACKGROUND: In experimental early painful diabetic neuropathy, persistent hyperglycaemia induces dys-regulated sodium channel (Navs) expression in the dorsal root ganglion (DRG) and activates microglia in the spinal dorsal horn (SDH). However, information on diabetes-induced chronic neuropathic pain is limited. Therefore, we investigated abnormal Navs in the DRG and activated glial cells in the SDH of diabetic rats with chronic neuropathic pain. METHODS: Sixty-six rats were divided into diabetic and control groups: control rats (n = 18; 1 mL of normal saline via the right femoral vein) and diabetic rats [n = 48; 60 mg/kg streptozotocin (STZ) via the right femoral vein]. Hindpaw behavioural tests, Navs expression in the DRG, activation of glial cells in the SDH and the number of neurons in the SDH were measured at 1 and 2 weeks, and 1, 2, 3 and 6 months following saline and STZ administration. RESULTS: All diabetic rats exhibited hyperglycaemia from day 7 to 6 months. The diabetic rats decreased withdrawal threshold to mechanical stimuli but had blunted responses to thermal stimuli. Consistent up-regulation of Nav1.3 and down-regulation of Nav1.8 was observed. Microglial cells were activated early in the SDH and lasted for 6 months. A positive correlation between mechanical allodynia, Nav1.3 and microglial activation was observed. In addition, microglia activation in the SDH of STZ-induced diabetes was mediated, in part, by phosphorylation of p-38 mitogen-activated protein kinase. CONCLUSIONS: Diabetic rats showed hindpaw mechanical allodynia for 6 months. Persistent mechanical allodynia was positively associated with sustained increased activation of Nav1.3 and increased p38 phosphorylation in activated microglia.

Left endobronchial intubation with a double-lumen tube using direct laryngoscopy or the Trachway® video stylet.

We compared direct laryngoscopy with a Macintosh blade vs indirect bronchoscopy with a Trachway® stylet, for endobronchial intubation with a left-sided double-lumen tube. We allocated participants scheduled for thoracic surgery and who had normal predicted laryngoscopy, 30 to each group. The mean (SD) intubation times with laryngoscope and Trachway were 48 (11) s vs 28 (4) s, respectively, p < 0.001. The rates of hoarseness on the first postoperative day, categorised as none/mild/moderate/severe, were 10/12/7/1 and 22/6/2/0, respectively, p = 0.008, without differences on subsequent days. Left endobronchial intubation with a double-lumen tube is slower using direct laryngoscopy and causes more hoarseness than indirect bronchoscopy with a Trachway stylet.

Neuroprotective and anti-inflammatory activities of atorvastatin in a rat chronic constriction injury model.

Atorvastatin is an HMG-CoA reductase inhibitor used to treat hypercholesterolemic conditions associated with hypertension. This study aims to investigate the anti-inflammatory and neuroprotective effects of atorvastatin on peripheral neuropathic pain. Peripheral neuropathic pain was induced by chronic constriction injury (CCI) in Sprague-Dawley rats. Rats were divided into 3 groups including sham-operated, CCI, and atorvastatin-treated. Atorvastatin (10 mg/kg) or phosphate-buffered saline was orally administered for 2 weeks. All animals were assessed by neurobehavioral tests before surgery and at days 3, 7, 14 after surgery. Inflammatory and neuroprotective factors were evaluated by Western blot analysis. eNOS, COX2 and iNOS in the sciatic nerve were also studied using immunohistochemistry. Atorvastatin attenuated CCI-induced nociceptive sensitization and thermal hyperalgesia in a time-dependent manner. Atorvastatin improved CCI-induced neurobehavioral/inflammatory activity by inhibition of TGF-beta, pIkB/IkB, NFkB, COX2, iNOS, EP1 and EP4 in the sciatic nerve. Atorvastatin was also found to increase neuroprotection factors pAkt/Akt, eNOS and VEGF. Taken together, these data indicate that atorvastatin could protect the sciatic nerve against CCI-induced neuroinflammation and nociception.

Comparison of the GlideScope® videolaryngoscope and the Macintosh laryngoscope for double-lumen tube intubation.

Intubation with a double-lumen tube is important for achieving one-lung ventilation and facilitating thoracic surgery. The GlideScope(®) videolaryngoscope (Verathon Inc., Bothell, WA, USA) is designed to assist tracheal intubation for patients with a difficult airway. We wished to compare the GlideScope and direct laryngoscopy for double-lumen tube intubation. Sixty adult patients requiring a double-lumen tube for thoracic surgery and predicted uncomplicated laryngoscopy were randomly assigned to a direct Macintosh laryngoscopy group (n = 30) or a GlideScope group (n = 30). The mean (SD) duration of intubation was longer in the Macintosh group (62.5 (29.7) s) than in the GlideScope group (45.6 (10.7) s; p = 0.007). There was no difference in the success of the first attempt at intubation (26/30 (87%) and 30/30 (100%) for Macintosh and GlideScope groups, respectively; p = 0.112). The incidence of sore throat and hoarseness was higher in the Macintosh group (18 (60%) and 14 (47%), respectively) than in the GlideScope group (6 (20%) and 4 (13%), respectively; p = 0.003 and 0.004). We conclude that double-lumen tube intubation in patients with predicted normal laryngoscopy is easier using the GlideScope videolaryngoscope than the Macintosh laryngoscope.

Effects of topical corticosteroids on the sciatic nerve: an experimental study to adduce the safety in treating carpal tunnel syndrome.

Despite known detrimental effects on the blood flow and histology of nerves after intraneural corticosteroid injection, the neurotoxic effect of corticosteroids remains unclear. We investigated the effect of topical dexamethasone on nerve function. Two sponge strips soaked with dexamethasone at doses of 0.8, 1.6, and 3.2 mg were placed under and over the left sciatic nerve of adult Wistar rats for 30 minutes. Mixed-nerve-elicited somatosensory evoked potentials and dermatomal somatosensory evoked potentials were evaluated immediately and repeated together with functional tests and histology 2 weeks later. Evoked potential amplitude was dose-dependently lower and latency was prolonged in dexamethasone-treated sciatic nerves compared to controls. The suppression persisted with incomplete recovery for at least 4 hours, but differences between treated and control nerves were not significant after 2 weeks. Topical dexamethasone adversely affected neural conduction in a dose-dependent manner. Our results suggest that caution is required when using large doses of corticosteroid for injection of the carpal tunnel.

Malignant mixed müllerian tumor of primary mesenteric origin associated with a synchronous ovarian cancer: case report and literature review.

Malignant mixed müllerian tumor (MMMT) is a rare tumor in females and extragenital MMMT is even more so. We report a patient with MMMT primarily in the mesentery with synchronous ovarian cancer. In the English literature, 42 cases of extragenital MMMT have been reported other than the presented case, and this is only the second MMMT arising from the mesentery. Furthermore, among the cases reviewed, MMMTs tend to be associated with synchronous or metachronous colonic cancer or gynecologic tumors originating from the müllerian duct, including ovarian tumors, fallopian tube cancer, endometrial cancer, cervical cancer, and serous carcinoma of the peritoneum (14 out of 43 patients; 32.6%). The risk factors for MMMT include obesity, nulliparity, exogenous estrogen, and long-term tamoxifen use. The prognosis of MMMT is catastrophic and the treatment is based on the experience of those of uterine sarcomas, which is composed of operation, radiotherapy and chemotherapy.

Optimal skin surface landmark for the SVC-RA junction in cancer patients requiring the implantation of permanent central venous catheters.

We compared four different skin surface landmarks, the lower margin of the right 2nd costo-sternal junction (point A); the upper margin of the right 3rd costo-sternal junction (point B); the lower margin of the right 3rd costo-sternal junction (point C); and a point 5 cm below the manubrio-sternal junction (point D), in 20 cancer patients undergoing insertion of permanent central venous catheters whose tips were placed near the superior vena cava - right atrium (SVC-RA) junction under transoesophageal echocardiography guidance. The landmark was satisfactory if it was located within 1 cm of the SVC-RA junction. Points C and D were closer to the SVC-RA junction than points A and B (p < 0.0001). However, point C had the highest incidence (C: 70%, A: 0%, B: 20%, D: 30%, p < 0.0001) of being within 1 cm of the SVC-RA junction.

Tumour lysis syndrome developing during an operation.

We describe an unusual case of tumour lysis syndrome in a child with a high-grade lymphoma undergoing a staging laparotomy. The patient presented with a refractory ventricular arrhythmia, which required continuous resuscitation in the operating room and continuous venous-venous haemodialysis in the intensive care unit. This case report suggests that surgery is a possible trigger for developing tumour lysis syndrome, so anaesthetists should be alert to this possibility during surgery in patients with pre-existing high tumour burdens.

Comparison of radiographic landmarks and the echocardiographic SVC/RA junction in the positioning of long-term central venous catheters.

BACKGROUND: When implanting a permanent central venous catheter, the usual aim is to place the tip at the superior vena cava/right atrial (SVC/RA) junction. However, data validating radiographic landmarks of the SVC/RA junction are limited. This investigation was undertaken to compare the radiographic landmarks with the SVC/RA junction as determined by transesophageal echocardiography (TEE). METHODS: In 20 adult oncologic patients undergoing implantation of a permanent subcutaneous central venous catheter, the catheter tip was placed in the SVC/RA junction under TEE guidance. The position of the catheter tip on chest X-ray, which represented the echocardiographic SVC/RA junction, was then compared with a standard radiographic landmark of the SVC/RA junction and with thoracic vertebral levels. RESULTS: In all but two patients radiographic SVC/RA junctions were identified. The echocardiographic SVC/RA junction ranged from 0.6 cm above to 2.8 cm below the radiographic SVC/RA junction. There was a significant difference between the distance from the carina to the radiographic SVC/RA junction and the distance from the carina to the echocardiographic SVC/RA junction. The thoracic vertebral body correlating with the echocardiographic SVC/RA junction ranged from the sixth to the ninth level. CONCLUSION: Both the radiographic SVC/RA junction and the thoracic vertebral bodies are not reliable landmarks for the SVC/RA junction defined by TEE. Physicians should be aware that using the radiographic SVC/RA junction to confirm proper positioning of permanent central venous catheters risks placing the catheter tip in the upper SVC, with subsequent potential long-term complications. More reliable radiographic landmarks for the SVC/RA junction should be investigated.

Correct positioning of the venous port-a-cath catheter: comparison of intravascular electrocardiography signal from guidewire and sodium bicarbonate flushed catheter.

A prospective study comparing the efficacy of wire-conducted intravascular ECG (IVECG) signal and signal from the port with a sodium bicarbonate (NaHCO3) flushed catheter to correctly place a catheter tip was carried out in 100 patients. The correct position of the catheter tip was confirmed as follows: with technique G, the IVECG signal was conducted from a guide wire to identify the tip position. With technique P, the IVECG signal was conducted from the port with a NaHCO3 (0.8 mmol/ml) flushed catheter to ascertain the tip position. Each patient received both technique G and technique P in a randomized sequence. The quality of IV-ECG signals, which included baseline drift, P wave pattern and QRS wave pattern, were assessed for ten seconds. Satisfactory quality of these IVECG signals was observed in all of the patients with technique P and 90 of the 100 patients with technique G, and this difference was significant (P=0.001). There was no obvious difference between the techniques in catheter tip placement time or the measured optimal catheter length. The incidence of atrial premature contractions was higher with technique G than with technique P (13% vs 2%; P=0.003). Therefore, technique P is a practical alternative for correctly placing the catheter tip of a Port-A-Cath.

Transcriptional mRNA of bone morphogenetic proteins 2, 3, 4, and 5 in trigeminal nerve, benign and malignant peripheral nerve sheath tumors.

Bone morphogenetic proteins (BMPs) have been shown to play an important role in cell growth and differentiation. BMPs, a rapidly expanding family closely related to transforming growth factor-beta (TGF-beta) superfamily, have been proven recently to possess a regulatory role and neurotrophic capacity in neurogenesis. The aim of the present study is to reveal the relationship among BMPs, peripheral nerve and neoplastic lesions of nerve sheath tumors. The mRNA transcriptions of BMP 2, 3, 4 and 5 in 12 cases of schwannoma, four cases of malignant schwannoma and three cases of trigeminal neuralgia were detected using an in situ hybridization technique. Our results demonstrated that the myelin sheaths of schwann cell from the peripheral neuroectomy of trigeminal neuralgia were positively expressing mRNA of BMP-2, 3, 4 and 5. However, the nerve fibers of trigeminal nerve showed only BMP-2 positive staining. All of the neoplastic lesions of nerve sheath showed a consistent but variant expression of BMP-2, 3, 4, and 5. Except for the BMP-4 mRNA, the expression signals of BMP-2, 3 and 5 mRNA in malignant schwannoma were relatively lower than in benign lesions. On the basis of the findings, we concluded that selected members of BMPs existed in the peripheral nerves and might contribute to the health maintenance, proliferation, regeneration and neoplastic transformation of the peripheral nerve system. Moreover, the effects of BMP-2, 3, 4 and 5 on peripheral nerve system and its neoplastic transformation might be widespread, diverse and antagonistic.

Intraoperative stroke under epidural anesthesia for bipolar hemiarthroplasty in a patient with multiple myeloma: a case report.

A 56-yr-old, 58-kg woman with right femoral neck fracture underwent right bipolar hemiarthroplasty. Her medical problems included diabetes mellitus and multiple myeloma. Epidural anesthesia was performed uneventfully. No other drug except for local anesthetic (2% lidocaine) was administered during the procedure. Unfortunately, we "witnessed" the dramatically hemodynamic change of an intraoperative stroke, which was preceded by a hypotensive episode and followed by sustained hypertension. The stroke was presented with decreased level of consciousness initially and confirmed by the brain CT, which revealed acute infarction at the right middle cerebral artery territory, four days after the procedure. Multiple mechanisms such as intraoperative hypotensive episode and vascular atherosclerotic change due to poor controlled diabetes mellitus might be involved in the event. In the meanwhile, hyperviscosity (3.7 centipoise units of the patient v.s. 1.4-1.8 centipoise units of normal range) caused by multiple myeloma might also have contributed to the intraoperative stroke. Clinical presentation of this case will be discussed.