Cheng-Wei Lu

Complexity of intracranial pressure correlates with outcome after traumatic brain injury

This study applied multiscale entropy analysis to investigate the correlation between the complexity of intracranial pressure waveform and outcome after traumatic brain injury. Intracranial pressure and arterial blood pressure waveforms were low-pass filtered to remove the respiratory and pulse components and then processed using a multiscale entropy algorithm to produce a complexity index. We identified significant differences across groups classified by the Glasgow Outcome Scale in intracranial pressure, pressure-reactivity index and complexity index of intracranial pressure (P < 0.0001; P = 0.001; P < 0.0001, respectively). Outcome was dichotomized as survival/death and also as favourable/unfavourable. The complexity index of intracranial pressure achieved the strongest statistical significance (F = 28.7; P < 0.0001 and F = 17.21; P < 0.0001, respectively) and was identified as a significant independent predictor of mortality and favourable outcome in a multivariable logistic regression model (P < 0.0001). The results of this study suggest that complexity of intracranial pressure assessed by multiscale entropy was significantly associated with outcome in patients with brain injury.

Adaptive Computation of Multiscale Entropy and Its Application in EEG Signals for Monitoring Depth of Anesthesia During Surgery

Entropy as an estimate of complexity of the electroencephalogram is an effective parameter for monitoring the depth of anesthesia (DOA) during surgery. Multiscale entropy (MSE) is useful to evaluate the complexity of signals over different time scales. However, the limitation of the length of processed signal is a problem due to observing the variation of sample entropy (S E ) on different scales. In this study, the adaptive resampling procedure is employed to replace the process of coarse-graining in MSE. According to the analysis of various signals and practical EEG signals, it is feasible to calculate the S E from the adaptive resampled signals, and it has the highly similar results with the original MSE at small scales. The distribution of the MSE of EEG during the whole surgery based on adaptive resampling process is able to show the detailed variation of S E in small scales and complexity of EEG, which could help anesthesiologists evaluate the status of patients.

Analysis of EEG via Multivariate Empirical Mode Decomposition for Depth of Anesthesia Based on Sample Entropy

In monitoring the depth of anesthesia (DOA), the electroencephalography (EEG) signals of patients have been utilized during surgeries to diagnose their level of consciousness. Different entropy methods were applied to analyze the EEG signal and measure its complexity, such as spectral entropy, approximate entropy (ApEn) and sample entropy (SampEn). However, as a weak physiological signal, EEG is easily subject to interference from external sources such as the electric power, electric knives and other electrophysiological signal sources, which lead to a reduction in the accuracy of DOA determination. In this study, we adopt the multivariate empirical mode decomposition (MEMD) to decompose and reconstruct the EEG recorded from clinical surgeries according to its best performance among the empirical mode decomposition (EMD), the ensemble EMD (EEMD), and the complementary EEMD (CEEMD) and the MEMD. Moreover, according to the comparison between SampEn and ApEn in measuring DOA, the SampEn is a practical and efficient method to monitor the DOA during surgeries at real time.

Does the Suggested Lightwand Bent Length Fit Every Patient?The Relation between Bent Length and Patient's Thyroid Prominence–to–Mandibular Angle Distance

Background To date, no study has explored the effect of bent length on lightwand intubation. For successful intubation in daily practice, the authors found that bent length should be approximated to the patients thyroid prominence-to-mandibular angle distance (TMD), but some patients have a TMD much shorter than the suggested bent length range. The purposes of this study were to understand TMD distribution in adults and to test the influence of bent length on lightwand intubation. Methods The TMD, airway, and demographic data of 379 patients were collected. To test the bent length influence, patients were enrolled in group A (158 patients, TMD ≤ 5.5 cm) and group B (131 patients, TMD > 5.5 cm) and were intubated randomly using the lower (6.5 cm) and upper (8.5 cm) limits of the suggested range. Success rate and lightwand search time were compared. Results In group A, the success rate was 98.8% with 6.5-cm bent length and 78.2% with 8.5-cm bent length (P < 0.05). Search times were 5.7 ± 2.90 and 8.9 ± 5.80 s with 6.5- and 8.5-cm bent length, respectively (P < 0.01). In group B, there was no statistical difference in success rate and search time between 6.5- and 8.5-cm bent length. Conclusion The suggested range was suitable for patients in group B (TMD > 5.5 cm). However, in group A (≤5.5 cm), the large discrepancy between the upper limit of the suggested range and this TMD caused difficulty in lightwand intubation. A 6.5-cm bent length is more suitable than an 8.5-cm bent length in these patients.

Complications of Intraoperative Transesophageal Echocardiography in Adult Cardiac Surgical Patients—Experience of Two Institutions in Taiwan

There is some safety concern about transesophageal echocardiography (TEE) when it is used routinely during cardiac operations. The purpose of this investigation was to study the incidence of intraoperative TEE-associated complications in adult cardiac surgical patients. The study population comprised 6255 consecutive adult cardiac surgical patients with intraoperative TEE examinations. TEE-associated complications occurred in 25 patients (0.4%). Most of these complications consisted of oropharyngeal mucosal bleeding (15/25, 60%). Esophageal perforation occurred in one patient. Two patients experienced upper gastrointestinal bleeding. Seven patients experienced dental injuries, and TEE probe insertion failed in 10 patients. We conclude that intraoperative TEE-associated complications in cardiac operations is very low; the complication rate we found was comparable to previously reported values.

Effective Epidural Blood Patch Volumes for Postdural Puncture Headache in Taiwanese Women

BACKGROUND/PURPOSE Epidural blood patch (EDBP) is the most commonly used method to treat postdural puncture headache (PDPH). The optimal or effective blood volume for epidural injection is still controversial and under debated. This study compared the therapeutic efficacy of 7.5 mL blood vs. 15 mL blood for EDBP via epidural catheter injection. METHODS Thirty-three patients who suffered from severe PDPH due to accidental dural puncture during epidural anesthesia for cesarean section or epidural analgesia for labor pain control were randomly allocated into two groups. EDBP was conducted and autologous blood 7.5 mL or 15 mL was injected via an epidural catheter in the semi-sitting position in Group I (n = 17) and II (n = 16), respectively. For all patients in both groups, the severity of PDPH was registered on a 4-point scale (none, mild, moderate, severe) and assessed 1 hour, 24 hours and 3 days after EDBP. RESULTS There was no significant difference between the two groups of patients at all time points with respect to the severity of PDPH. Two patients in Group I and nine in Group II developed nerve root irritating pain during blood injection (p < 0.05). No systemic complications were noted in both groups of patients throughout EDBP injection. CONCLUSION We conclude that injection of 7.5 mL autologous blood into the epidural space is comparable to 15 mL blood in its analgesic effect on PDPH, but with less nerve root irritating pain during injection.

Local infusion of bupivacaine combined with intravenous patient-controlled analgesia provides better pain relief than intravenous patient-controlled analgesia alone in patients undergoing minimally invasive cardiac surgery

OBJECTIVE This prospective randomized double-blind study examined the effect of local wound infusion of anesthetics on pain control in the thoracotomy wound of patients undergoing minimally invasive cardiac surgery. METHODS Patients who underwent coronary artery bypass grafting or cardiac valvular procedures via a minimally invasive thoracotomy were studied. Patients were enrolled and randomly allocated to two groups with different modalities of postoperative analgesia. The thoracotomy wound infusion group received 0.15% bupivacaine infused continuously at 2 mL/h through a catheter embedded in the wound, as well as intravenous patient-controlled analgesia. The control group had patient-controlled analgesia alone with a sham thoracotomy wound infusion of normal saline. Verbal analog pain scores (0-10 points) and recovery profiles were investigated. RESULTS There were 19 patients in each group for complete data analysis. On the first day after the operation, infusion of local anesthetics significantly reduced the verbal analog pain scores both at rest and during motion (thoracotomy wound infusion vs control). The improved pain relief with thoracotomy wound infusion persisted at day 3 and even at 3 months after the operation. No difference was noted about time to extubation, length of intensive care unit stay, or hospital stay. CONCLUSION In this controlled double-blind study, thoracotomy wound infusion and patient-controlled analgesia were superior to patient-controlled analgesia alone in reducing pain at 1, 3, and 90 days after minimally invasive cardiac surgery.

Antimicrobial effect of continuous lidocaine infusion in a Staphylococcus aureus-induced wound infection in a mouse model.

AbstractContinuous infusion of local anesthetics in surgical wounds has been shown to be an effective technique for postoperative analgesia. To investigate the potential antimicrobial effect of continuous local anesthetic infusion, we adapted a mouse model of surgical wound infection to examine effects on antibacterial response. Forty male BALB/c mice were randomized into 2 groups. An incision wound was made over the dorsal flank and instilled with Staphylococcus aureus. An osmotic pump was then implanted to deliver either 0.9% NaCl or 2% lidocaine continuously. Each wound was cultured postoperatively at 2 days, and the colony count of S. aureus was determined. Results showed that the number of colony-forming units of S. aureus measured in wounds treated with lidocaine displayed a nearly 10-fold reduction compared to the wounds in the saline group (P = 0.009). The demonstrated antibacterial activity indicates that local anesthetic infusion may play a role in prophylaxis for surgical wound infections.

Antiemetic efficacy of metoclopramide and diphenhydramine added to patient-controlled morphine analgesia: a randomised controlled trial.

Background and objective The objective of this study was to assess whether antiemetic drugs metoclopramide and diphenhydramine, administered together as opposed to alone, can have better efficacy in preventing postoperative nausea and vomiting when added to patient-controlled morphine analgesia. Patients and methods During the period July 2007 to August 2008, 200 women scheduled for abdominal total hysterectomy were randomised to one of four postoperative, patient-controlled analgesia regimens: group 1, morphine 1 mg ml−1; group 2, morphine 1 mg ml−1 with metoclopramide 0.5 mg ml−1; group 3, morphine 1 mg ml−1 with diphenhydramine 0.6 mg ml−1; and group 4, morphine 1 mg ml−1 with metoclopramide 0.5 mg ml−1 and diphenhydramine 0.6 mg ml−1. Dexamethasone 4 mg was administered to all patients in all groups after anaesthesia induction as a prophylactic antiemetic medication, and prochlorperazine 5 mg was administered by intramuscular injection as necessary as a salvage/rescue therapy. Nausea, vomiting, pruritus, level of sedation, pain and morphine consumption were compared between the four groups. Results The incidence of nausea was significantly (P < 0.05) lower in group 4 compared to the other groups. In addition, there was a significant (P = 0.006) difference in the incidence of vomiting between groups 1 and 4. Repeated measurement analysis showed that numeric rating scale scores for group 4 were significantly (P < 0.001) lower than those for the other groups. Conclusion Results of this study showed that a combination of metoclopramide with diphenhydramine in patients treated with dexamethasone at anaesthesia induction decreased postoperative nausea and vomiting compared to metoclopramide or diphenhydramine in these patients, when added to patient-controlled anaesthesia with morphine.

A critical care monitoring system for depth of anaesthesia analysis based on entropy analysis and physiological information database.

Diagnosis of depth of anaesthesia (DoA) plays an important role in treatment and drug usage in the operating theatre and intensive care unit. With the flourishing development of analysis methods and monitoring devices for DoA, a small amount of physiological data had been stored and shared for further researches. In this paper, a critical care monitoring (CCM) system for DoA monitoring and analysis was designed and developed, which includes two main components: a physiologic information database (PID) and a DoA analysis subsystem. The PID, including biologic data and clinical information was constructed through a browser and server model so as to provide a safe and open platform for storage, sharing and further study of clinical anaesthesia information. In the analysis of DoA, according to our previous studies on approximate entropy, sample entropy (SampEn) and multi-scale entropy (MSE), the SampEn and MSE were integrated into the subsystem for indicating the state of patients underwent surgeries in real time because of their stability. Therefore, this CCM system not only supplies the original biological data and information collected from the operating room, but also shares our studies for improvement and innovation in the research of DoA.