Mei-Yung Tsou

Thromboelastography-guided transfusion decreases intraoperative blood transfusion during orthotopic liver transplantation: randomized clinical trial.

OBJECTIVE To test in a prospective randomized study the hypothesis that use of thromboelastography (TEG) decreases blood transfusion during major surgery. MATERIAL AND METHODS Twenty-eight patients undergoing orthotopic liver transplantation were recruited over 2 years. Patients were randomized into 2 groups: those monitored during surgery using point-of-care TEG analysis, and those monitored using standard laboratory measures of blood coagulation. Specific trigger points for transfusion were established in each group. RESULTS In patients monitored via TEG, significantly less fresh-frozen plasma was used (mean [SD], 12.8 [7.0] units vs 21.5 [12.7] units). There was a trend toward less blood loss in the TEG-monitored patients; however, the difference was not significant. There were no differences in total fluid administration and 3-year survival. CONCLUSION Thromboelastography-guided transfusion decreases transfusion of fresh- frozen plasma in patients undergoing orthotopic liver transplantation, but does not affect 3-year survival.

Paraplegia after delayed detection of inadvertent spinal cord injury during thoracic epidural catheterization in an anesthetized elderly patient

We report a case of permanent paraplegia in an 81-yr-old patient who had thoracic epidural catheterization performed under general anesthesia for abdominal surgery. The epidural needle was introduced at the T9-10 interspace, and 3 passes were made to locate the epidural space with the loss-of-resistance-to-air technique. During the postoperative epidural pump infusion, the patient was unaware of the progressive motor and sensory impairment. Sensory loss below T11 and paraplegia with no movement of either lower extremity were identified 8 h after surgery. Magnetic resonance imaging demonstrated an intramedullary split-like lesion extending from T4 to T12 and an intramedullary air bubble at T9. Spinal cord injury caused by an intracord catheterization with subsequent local anesthetic injection was diagnosed. Little improvement was noted after large-dose IV methylprednisolone for initial treatment and subsequent rehabilitation for 6 mo. The possible causes of the delayed detection of the neurologic deficits and the timing of performing epidural anesthesia are discussed.

A New Technique to Assist Epidural Needle Placement Fiberoptic-guided Insertion Using Two Wavelengths

Background:Up to 10% of epidurals fail due to incorrect catheter placement. We describe a novel optical method to assist epidural catheter insertion in a porcine model. Methods:Optical emissions were tested on ex vivo tissues from porcine paravertebral tissues to identify optical reflective spectra. The wavelengths of 650 and 532 nm differentiated epidural space from the ligamentum flavum. We then used a hollow stylet that contained optical fibers to place epidural needles in anesthetized pigs. Real-time data were displayed on an oscilloscope and stored for analysis. A total of 50 punctures were done in four laboratory pigs. Data were expressed as mean ± SD. Results:Paired t test shows significant optical differences between the epidural space and the ligamentum flavum at both 650 nm (P < 0.001) and 532 nm (P = 0.014). Mean magnitudes for 650 nm, 532 nm, and their ratio were 3.565 ± 0.194, 2.542 ± 0.145, and 0.958 ± 0.172 at epidural space and 3.842 ± 0.191, 2.563 ± 0.131, and 1.228 ± 0.244 at ligamentum flavum, respectively. There were no differences in the optical characteristics of the ligamentum flavum and epidural space at different levels in the lumbar and thoracic region (two-way ANOVA P > 0.05). Conclusions:This is the first study to introduce a new optical method to localize epidural space in a porcine model. Epidural space could be identified by the changes in the reflective pattern of light emitted at 650 nm, which were specific for the ligamentum flavum and dural tissue. Real-time optical information successfully guided a modified Tuohy needle into the epidural space.

Factors Affecting Patient-controlled Analgesia Requirements

BACKGROUND/PURPOSE Intravenous patient-controlled analgesia (IVPCA) is one of the most widely used postoperative analgesic methods. Many factors could affect the total analgesic consumption of IVPCA. This retrospective study investigated the relationship between patient characteristics and total morphine consumption during a 3-day course of postoperative IVPCA. METHODS Patients receiving surgery under general anesthesia with postoperative IVPCA for 3 days during the period between January 2002 and December 2003 were included. Patient data including age, sex, weight, height, body mass index (BMI), operation type and site were collected. Total morphine consumption was recorded at the end of the 3-day IVPCA course. Stepwise regression analyses were conducted to select factors significantly associated with morphine consumption. Stratified analyses were also conducted among different surgical, BMI and age subgroups. RESULTS A total of 1308 patients (646 men, 662 women) were included in the analysis. For all operations, weight, age, procedures involving malignant disease, and surgical sites were significantly associated with total morphine consumption. The R and adjusted R2 values of the selected model were 0.509 and 0.256, respectively. Weight was the only common factor among all stratified analyses (all p < 0.001). Age was negatively correlated with morphine consumption. Gender was not a significant factor except in lower abdominal operations. Height was not associated with total morphine consumption. BMI status was not significantly associated with components of the selected factors. CONCLUSION This study demonstrated that weight and surgical sites significantly influence total IVPCA requirements. The effect of surgical sites should be considered when evaluating the influence of demographic characteristics on IVPCA demand.

Eyes in the needle: novel epidural needle with embedded high-frequency ultrasound transducer--epidural access in porcine model.

Background:Epidural needle insertion is usually a blind technique where the rate of adverse events depends on the experience of the operator. A novel ultrasound method to guide epidural catheter insertion is described. Methods:An ultrasound transducer (40 MHz, a −6 dB fractional bandwidth of 50%) was placed into the hollow chamber of an 18-gauge Tuohy needle. The single crystal was polished to a thickness of 50 &mgr;m, with a width of 0.5 mm. Tissue planes were identified from the reflected signals in an A-mode display. The device was inserted three times into both the lumbar and thoracic regions of five pigs (average weight, 20 kg) using a paramedian approach at an angle of 35–40°. The epidural space was identified using signals from the ligamentum flavum and dura mater. Epidural catheters were placed with each attempt and placement confirmed by contrast injection. Results:The ligamentum flavum was identified in 83.3% of insertions and the dura mater in all insertions. The dura mater signal was stronger than that of the ligamentum flavum and served as a landmark in all epidural catheter insertions. Contrast studies confirmed correct placement of the catheter in the epidural space of all study animals. Conclusions:This is the first study to introduce a new ultrasound probe embedded in a standard epidural needle. It is anticipated that this technique could reduce failed epidural blocks and complications caused by dural puncture.

Intraoperative administration of tramadol for postoperative nurse-controlled analgesia resulted in earlier awakening and less sedation than morphine in children after cardiac surgery

In adults, intraoperative administration of tramadol could result in earlier recovery and less sedation than morphine. In this controlled, randomized, double-blind study, we investigated whether an intraoperative initial dose of tramadol could cause more rapid awakening from general anesthesia, less sedation, and earlier tracheal extubation than morphine in children during the immediate postoperative period. Forty children aged 1–6 yr, scheduled for atrial or ventricular septal defect repair and tracheal extubation in the pediatric intensive care unit, were randomly allocated to receive morphine, initial dose 0.2 mg/kg, or tramadol 2 mg/kg given at the end of sternal closure, followed by nurse-controlled analgesia (bolus 0.02 mg/kg of morphine and 0.2 mg/kg of tramadol) with background infusions (0.015 mg · kg−1 · h−1 for morphine and 0.15 mg · kg−1 · h−1 for tramadol). Postoperatively, children receiving tramadol had earlier awakening from general anesthesia (P = 0.02) and were less sedated at 1 and 2 h postoperatively (P = 0.03 and P = 0.01, respectively). Tracheal extubation was earlier in the tramadol group (P = 0.01). Lengths of pediatric intensive care unit stay did not differ between groups. Times to first trigger of nurse-controlled analgesia bolus and objective pain scores during the 48 h observation period were comparable between groups. The incidence of desaturation and emesis were similar between groups. The patients ate well and did not differ on Day 1 or Day 2.

Use of higher thromboelastogram transfusion values is not associated with greater blood loss in liver transplant surgery

Plasma‐containing products are given during the pre‐anhepatic stage of liver transplant surgery to correct abnormal thromboelastogram (TEG) values and prevent blood loss due to coagulation defects. However, evidence suggests that abnormal TEG results do not always predict bleeding. We questioned what effect using higher TEG values to initiate treatment would have on blood loss. A single transfusion protocol was used for all patients who underwent liver transplantation between 2007 and 2010. Thirty‐eight patients received coagulation products when standard TEG cutoff values were exceeded, whereas another 39 patients received coagulation products when the TEG values were 35% greater than normal. The results of postoperative coagulation tests for total blood loss and the use of blood products were compared for the 2 groups. When the critical TEG values for transfusion were higher, significantly fewer units of fresh frozen plasma (5.58 ± 6.49 versus 11.53 ± 6.66 U) and pheresis platelets (1.84 ± 1.33 versus 3.55 ± 1.43 U) were used. There were no differences in blood loss or postoperative blood product use. In conclusion, the use of higher critical TEG values to initiate the transfusion of plasma‐containing products is not associated with increased blood loss. Further testing is necessary to identify what TEG value predicts bleeding due to a deficit in coagulation factors. Liver Transpl 18:1254–1258, 2012.

Discriminant analysis for anaesthetic decision-making: an intelligent recognition system for epidural needle insertion

BACKGROUND Incorrect placement of epidural catheters causes medical complications. We used linear discriminant analysis (LDA) to develop an intelligent recognition system (i-RS) in order to guide epidural placement and reduce physician error. METHODS We analysed real-time dual-wavelength fibreoptic data recorded from the end of an epidural needle in a live porcine model. Two categories of tissue layers were necessary for correct placement of catheter: epidural space and ligamentum flavum. The data were tested using linear, quadratic and logistic parametric analysis to identify which method could distinguish the two anatomical structures. RESULTS LDA was the best fit for our model. There was ∼80% sensitivity and specificity for correct anatomical identification. Error rates based on cross-validation were 17.0% for the epidural space and 18.6% for ligamentum flavum. Error rates were greater with the 532 nm compared with 650 nm wavelength. CONCLUSIONS The sensitivity and specificity of LDA for identifying the correct anatomical structure was similar to a physician who is an expert in epidural placement. Overall performance of an i-RS could be improved by expanding the database for decision-making and adding a category of uncertainty. This would reduce complications caused by incorrect epidural placement.

A Modified Method for Intubation of a Patient with Ankylosing Spondylitis Using Intubating Laryngeal Mask Airway (LMA-Fastrach(superscript TM)-A Case Report

We present an instance of successful use of an intubating laryngeal mask airway (LMA-Fastrach(superscript TM)) and a Cook airway exchanger (CAE) for ventilation and intubation in a patientwith severe ankylosing spondilitis (AS) receiving total hip arthroplasty. This measure may serve as an effective alternative for airway management in patients with difficult airway. A 61-year-old male was scheduled for tight total hip arthroplasty because of degenerative osteoarthritis. He had been suffering from extensive ankylosing spondylitis, with the cervical spine markedly fixed in anterior flexion. Besides he could not open his mouth widely (35mm when fully open) also because of ankylosis of jaw. Although we advised an awake fiberoptic tracheal intubation for anesthesia but he refused owing to a previous painful experience. After induction of anesthesia with glycopyrrolate, fentanyl, thiamylal sodium and succinylcholine, we inserted a #5 Fastrach(superscript TM) ILMA for primary airway maintenance. Then through the lumen of the ILMA we introduced the CAE as a guide for endotracheal tube (ETT) intubation. After applying the RAPI-F1TTM adapter to the CAE, we connected it to the capnography monitor for the confirmation of airway. We finally inserted an endotracheal tube into the trachea using the CAE as a guide. The whole procedure was uneventful and smooth. In sum, the modified Fastrach(superscript TM) intubation method may facilitate tracheal intubation in patients with severe ankylosing spondiitis. It may be an alternative way for successful airway management in patients with difficult airway.

Domino liver graft from a patient with homozygous familial hypercholesterolemia.

Liu C, Niu D‐M, Loong C‐C, Hsia C‐Y, Tsou M‐Y, Tsai H‐L, Wei C. Domino liver graft from a patient with homozygous familial hypercholesterolemia.
Pediatr Transplantation 2010: 14:E30–E33.