Effect of the Brief Instructional Video Intervention on the Quality of Cardiopulmonary Resuscitation.

Background: Chest compressions are the basis of cardiopulmonary resuscitation (CPR), and high-quality chest compressions can improve survival rate in patients with out-of-hospital cardiac arrest. Although many efforts have been made to improve the quality of CPR in inexperienced adults, the results are still not high, especially during emergencies. The primary purpose of this study is to investigate whether a brief instructional chest compression-only CPR video could improve chest compression quality in inexperienced adults. Methods: One hundred adults with no CPR experience (age: 20.28 ± 2.28 years; women: 50, men: 50) participated in this study. Participants completed body composition and handgrip strength measurements, and performed two CPR quality tests on the Laerdal® Little Anne QCPR Manikin, namely without video-CPR (WV-CPR) and video-CPR (V-CPR). The WV-CPR quality test was performed first. After 2 minutes of continuous chest compression, the participants rested for 10 seconds and repeated 3 cycles (phase 1, phase 2, and phase 3). After resting for more than 72 hours, V-CPR quality test was conducted. During the V-CPR with video intervention, the participants also continued to compress the chest for 2 minutes, and then rested for 10 seconds, repeating 3 cycles. Results: In phase 1, compared with WV-CPR, the V-CPR has a significant increase (p < 0.001) in chest compression fraction (CCF) (56.31 ± 33.22% vs. 41.82 ± 32.30%) and percent of correct compression rate (PCCR) (96.17 ± 8.45% vs. 26.31 ± 37.55%). In addition, the V-CPR has significantly lower (p < 0.001) chest compression rate (CCR) (110.85 ± 2.40 cpm vs. 128.86 ± 24.52 cpm) and rating of perceived exertion (RPE) (11.89 ± 2.25 vs. 12.87 ± 2.25). For phases 2 through 3, V-CPR and WV-CPR achieved significant differences in CCF, CCD, CCR, PCCR, and RPE (p < 0.01). There were significant differences (p < 0.05) in CCF, CCD, chest compression rebound rate, and RPE among the different administration stages of both WV-CPR and V-CPR. Conclusions: The results of this study revealed that a brief instructional chest compression-only CPR video could improve chest compression quality for inexperienced adults by reducing fatigue and CCR, and increasing CCF and PCCR.

Death place and palliative outcome indicators in patients under palliative home care service: an observational study.

BACKGROUND: Dying at home accompanied by loved-ones is regarded favorably and brings good luck in Taiwan. This study aimed to examine the relevant factors affecting whether an individual dies at home or not in a group of terminal patients receiving palliative home care service. METHODS: The patients who were admitted to a palliative home care service at a hospital-affiliated home health care agency were consecutively enrolled between March 1, 2021 and March 31, 2022. During the period of care, the instruments of the palliative care outcomes collaboration was used to assess patients in each home visit twice a week, including symptom assessment scale, palliative care problem severity score, Australia-modified Karnofsky performance status, resource utilization groups-activities of daily living, and palliative care phase. RESULTS: There were 56 participants (53.6% female) with a median age of 73.0 years (interquartile range (IQR) 61.3-80.3 y/o), of whom 51 (91.1%) patients were diagnosed with cancer and 49 (96.1%) had metastasis. The number of home visits was 3.5 (IQR 2.0-5.0) and the average number of days under palliative home care service was 31 (IQR 16.3-51.5) before their death. After the end of the study, there was a significant deterioration of sleeping, appetite, and breathing problems in the home-death group, and appetite problems in the non-home death patients. However, physician-reported psychological/spiritual problems improved in the home-death group, and pain improved in the non-home death patients. Physical performance deteriorated in both groups, and more resource utilization of palliative care was needed. The 44 patients who died at home had greater cancer disease severity, fewer admissions, and the proportion of families desiring a home death for the patient was higher. CONCLUSIONS: Although the differences in palliative outcome indicators were minor between patients who died at home and those who died in the hospital, understanding the determinants and change of indicators after palliative care service at different death places may be helpful for improving the quality of end-of-life care.

A VLSI Chip for the Abnormal Heart Beat Detection Using Convolutional Neural Network.

The heart is one of the human body's vital organs. An electrocardiogram (ECG) provides continuous tracings of the electrophysiological activity originated from heart, thus being widely used for a variety of diagnostic purposes. This study aims to design and realize an artificial intelligence (AI)-based abnormal heart beat detection with applications for early detection and timely treatment for heart diseases. A convolutional neural network (CNN) was employed to achieve a fast and accurate identification. In order to meet the requirements of the modularity and scalability of the circuit, modular and efficient processing element (PE) units and activation function modules were designed. The proposed CNN was implemented using a TSMC 0.18 µm CMOS technology and had an operating frequency of 60 MHz with chip area of 1.42 mm2 and maximum power dissipation of 4.4 mW. Furthermore, six types of ECG signals drawn from the MIT-BIH arrhythmia database were used for performance evaluation. Results produced by the proposed hardware showed that the discrimination rate was 96.3% with high efficiency in calculation, suggesting that it may be suitable for wearable devices in healthcare.

Synthesis and Characterization of Sol-Gelled Barium Zirconate as Novel MTA Radiopacifiers.

Barium zirconate (BaZrO3, BZO), which exhibits superior mechanical, thermal, and chemical stability, has been widely used in many applications. In dentistry, BZO is used as a radiopacifier in mineral trioxide aggregates (MTAs) for endodontic filling applications. In the present study, BZO was prepared using the sol-gel process, followed by calcination at 700-1000 °C. The calcined BZO powders were investigated using X-ray diffraction and scanning electron microscopy. Thereafter, MTA-like cements with the addition of calcined BZO powder were evaluated to determine the optimal composition based on radiopacity, diametral tensile strength (DTS), and setting times. The experimental results showed that calcined BZO exhibited a majority BZO phase with minor zirconia crystals. The crystallinity, the percentage, and the average crystalline size of BZO increased with the increasing calcination temperature. The optimal MTA-like cement was obtained by adding 20% of the 700 °C-calcined BZO powder. The initial and final setting times were 25 and 32 min, respectively. They were significantly shorter than those (70 and 56 min, respectively) prepared with commercial BZO powder. It exhibited a radiopacity of 3.60 ± 0.22 mmAl and a DTS of 3.02 ± 0.18 MPa. After 28 days of simulated oral environment storage, the radiopacity and DTS decreased to 3.36 ± 0.53 mmAl and 2.84 ± 0.27 MPa, respectively. This suggests that 700 °C-calcined BZO powder has potential as a novel radiopacifier for MTAs.

Effects of Calcination Temperature on the Synthesis of One-Pot Sol-Gelled Barium Titanate Powder and Its Performance as an Endodontic Radiopacifier.

Barium titanate (BaTiO3, BTO), conventionally used for dielectric and ferroelectric applications, has been assessed for biomedical applications, such as its utilization as a radiopacifier in mineral trioxide aggregates (MTA) for endodontic treatment. In the present study, BTO powders were prepared using the sol-gel process, followed by calcination at 400-1100 °C. The X-ray diffraction technique was then used to examine the as-prepared powders to elucidate the effect of calcination on the phase composition and crystalline size of BTO. Calcined BTO powders were then used as radiopacifiers for MTA. MTA-like cements were investigated to determine the optimal calcination temperature based on the radiopacity and diametral tensile strength (DTS). The experimental results showed that the formation of BTO phase was observed after calcination at temperatures of 600 °C and above. The calcined powders were a mixture of BaTiO3 phase with residual BaCO3 and/or Ba2TiO4 phases. The performance of MTA-like cements with BTO addition increased with increasing calcination temperature up to 1000 °C. The radiopacity, however, decreased after 7 days of simulated oral environmental storage, whereas an increase in DTS was observed. Optimal MTA-like cement was obtained by adding 40 wt.% 1000 °C-calcined BTO powder, with its resulting radiopacity and DTS at 4.83 ± 0.61 mmAl and 2.86 ± 0.33 MPa, respectively. After 7 days, the radiopacity decreased slightly to 4.69 ± 0.51 mmAl, accompanied by an increase in DTS to 3.13 ± 0.70 MPa. The optimal cement was biocompatible and verified using MG 63 and L929 cell lines, which exhibited cell viability higher than 95%.

Endodontic Radiopacifying Application of Barium Titanate Prepared through a Combination of Mechanical Milling and Heat Treatment.

Mineral trioxide aggregates (MTA) are commonly used as endodontic filling materials but suffer from a long setting time and tooth discoloration. In the present study, the feasibility of using barium titanate (BTO) for discoloration and a calcium chloride (CaCl2) solution to shorten the setting time was investigated. BTO powder was prepared using high-energy ball milling for 3 h, followed by sintering at 700-1300 °C for 2 h. X-ray diffraction was used to examine the crystallinity and crystalline size of the as-milled and heat-treated powders. MTA-like cements were then prepared using 20-40 wt.% BTO as a radiopacifier and solidified using a 0-30% CaCl2 solution. The corresponding radiopacity, diametral tensile strength (DTS), initial and final setting times, and discoloration performance were examined. The experimental results showed that for the BTO powder prepared using a combination of mechanical milling and heat treatment, the crystallinity and crystalline size increased with the increasing sintering temperature. The BTO sintered at 1300 °C (i.e., BTO-13) exhibited the best radiopacity and DTS. The MTA-like cement supplemented with 30% BTO-13 and solidified with a 10% CaCl2 solution exhibited a radiopacity of 3.68 ± 0.24 mmAl and a DTS of 2.54 ± 0.28 MPa, respectively. In the accelerated discoloration examination using UV irradiation, the color difference was less than 1.6 and significantly lower than the clinically perceptible level (3.7). This novel MTA exhibiting a superior color stability, shortened setting time, and excellent biocompatibility has potential for use in endodontic applications.

Discoloration Improvement by Mechanically-Milled Binary Oxides as Radiopacifier for Mineral Trioxide Aggregates.

Mineral trioxide aggregates (MTA) have been widely used in endodontic treatments, but after some time, patients suffer tooth discoloration due to the use of bismuth oxide (Bi2O3) as a radiopacifier. Replacement of Bi2O3 with high energy ball-milled single (zirconia ZrO2; hafnia, HfO2; or tantalum pentoxide, Ta2O5) or binary oxide powder was attempted, and corresponding discoloration improvement was investigated in the present study. Bi2O3-free MTA is expected to exhibit superior discoloration. The radiopacity, diametral tensile strength, and discoloration of MTA-like cements prepared from the as-milled powder were investigated. Experimental results showed that MTA-like cements prepared using Ta2O5 exhibited a slightly higher radiopacity than that of HfO2 but had a much higher radiopacity than ZrO2. Milling treatment (30 min to 3 h) did not affect the radiopacities significantly. These MTA-like cements exhibited superior color stability (all measured ΔE00 < 1.0) without any perceptible differences after UV irradiation. MTA-like cements prepared using ZrO2 exhibited the best color stability but the lowest radiopacity, which can be improved by introducing binary oxide. Among the investigated samples, MTA-like cement using (ZrO2)50(Ta2O5)50 exhibited excellent color stability and the best overall performance with a radiopacity of 3.25 mmAl and a diametral tensile strength of 4.39 MPa.

Transplantation of endothelial progenitor cells improves pulmonary endothelial function and gas exchange in rabbits with endotoxin-induced acute lung injury.

BACKGROUND: Circulating endothelial progenitor cells (EPCs) have been therapeutically applied to aid vascular repair and myocardial regeneration. The number of circulating EPCs also provides invaluable outcome prediction for fatal diseases such as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). However, evidence for the therapeutic potential of EPCs in subjects with ALI/ADRS is limited. METHODS: Circulating EPCs were obtained from rabbits using Ficoll centrifugation. One week after culturing EPCs in endothelial growth medium-2, ALI was induced in rabbits by intratracheal instillation of lipopolysaccharide (500 µg/kg). Autologous EPCs or saline were administered IV after induction of ALI and animals were killed 2 days later. Pulmonary artery endothelial function and gas exchange were determined. Degrees of lung injury were assessed by alveolocapillary permeability, lung hemoglobin content, and myeloperoxidase activity. RESULTS: In comparison with controls, Po(2) in arterial blood was significantly elevated and pulmonary artery endothelium-dependent relaxation response was restored in rabbits receiving EPC transplantation. Lung water, Evan's blue, and bronchoalveolar lavage protein contents were significantly reduced in the EPC transplanted group, indicating a better preservation of the alveolocapillary membrane. Transplantation of EPCs decreased the lung hemoglobin level. Furthermore, expressions of CD11b and myeloperoxidase activity were also suppressed after administration of EPCs. CONCLUSIONS: Transplantation of EPCs restored pulmonary endothelial function, preserved integrity of the alveolocapillary barrier and suppressed the lung inflammatory response, thereby improving pulmonary gas exchange in rabbits with intratracheal lipopolysaccharide-induced ALI. Transplantation of EPCs can be a novel cell-based, endothelium-targeted therapeutic strategy for prevention and treatment of ALI/ARDS.

Effect of Tantalum Pentoxide Addition on the Radiopacity Performance of Bi2O3/Ta2O5 Composite Powders Prepared by Mechanical Milling.

Among the various phases of bismuth oxide, the high temperature metastable face-centered cubic δ phase attracts great attention due to its unique properties. It can be used as an ionic conductor or an endodontic radiopacifying material. However, no reports concerning tantalum and bismuth binary oxide prepared by high energy ball milling and serving as a dental radiopacifier can be found. In the present study, Ta2O5-added Bi2O3 composite powders were mechanically milled to investigate the formation of these metastable phases. The as-milled powders were examined by X-ray diffraction and scanning electron microscopy to reveal the structural evolution. The as-milled composite powders then served as the radiopacifier within mineral trioxide aggregates (i.e., MTA). Radiopacity performance, diametral tensile strength, setting times, and biocompatibility of MTA-like cements solidified by deionized water, saline, or 10% calcium chloride solution were investigated. The experimental results showed that subsequent formation of high temperature metastable ß-Bi7.8Ta0.2O12.2, δ-Bi2O3, and δ-Bi3TaO7 phases can be observed after mechanical milling of (Bi2O3)95(Ta2O5)5 or (Bi2O3)80(Ta2O5)20 powder mixtures. Compared to its pristine Bi2O3 counterpart with a radiopacity of 4.42 mmAl, long setting times (60 and 120 min for initial and final setting times) and 84% MG-63 cell viability, MTA-like cement prepared from (Bi2O3)95(Ta2O5)5 powder exhibited superior performance with a radiopacity of 5.92 mmAl (the highest in the present work), accelerated setting times (the initial and final setting time can be shortened to 25 and 40 min, respectively), and biocompatibility (94% cell viability).

Morphine enhances tissue content of collagen and increases wound tensile strength.

PURPOSE: Morphine is a commonly prescribed analgesic for wound pain. Previous studies have shown that morphine enhances accumulation of collagen in cultured fibroblasts. Because fibroblasts are important for the remodeling of connective tissue in incisional wound, this study investigates the biological effects of morphine on cutaneous collagen content and wound tensile strength. METHODS: A full-thickness incisional wound (2 cm in length) was created on the dorsum of mice followed by treatment with placebo or morphine (5 and 20 mg/kg/day, i.p.). Fourteen days later, tensile strength of the healed incisional wound was measured using a tensiometer. Protein expression of transforming growth factor (TGF)-beta1 and matrix metalloproteinases (MMP)-2 in the incisional wound tissue was analyzed. Degree of tissue remodeling and levels of collagen were determined by histological examination and a dye-binding collagen assay, respectively. RESULTS: Morphine enhanced the breaking strength of incisional wound 14 days after treatment (92 +/- 10, 102 +/- 10 and 134 +/- 12 mg for control, morphine 5 mg/kg/day and morphine 20 mg/kg/day, respectively; P = 0.03, n = 6-7). Protein expression of TGF-beta1 and MMP-2 was significantly enhanced in mice treated with morphine. Histological examination of the wound tissue showed evidence of increased thickness of the cutaneous fibrous layer and deposition of collagen in the high-dose morphine treatment group. Collagen assays also demonstrated that tissue concentrations of collagen were significantly increased in the wound tissue of morphine-treated animals on day 2 of drug treatment. CONCLUSION: The present study demonstrates that systemic administration of morphine enhances tissue collagen deposition in the cutaneous tissue, thereby increasing the tensile strength of the incisional wound.

Autologous transplantation of endothelial progenitor cells attenuates acute lung injury in rabbits.

BACKGROUND: Acute lung injury (ALI) and end-stage acute respiratory distress syndrome (ARDS) are among the most common causes of death in intensive care units. Activation and damage of pulmonary endothelium is the hallmark of ALI/ARDS. Recent studies have demonstrated the importance of circulating endothelial progenitor cells (EPCs) in maintaining normal endothelial function as well as endothelial repairing after vascular injury. Here, the authors present the first study demonstrating the therapeutic potential of EPCs in a rabbit model of ALI/ARDS. METHODS: Circulating EPCs were obtained from rabbits using Ficoll centrifugation. One week after culturing, ALI was induced in rabbits by oleic acid (75 mg/kg, intravenous), and autologous EPCs were transplanted intravenously. Vasomotor function of isolated pulmonary artery and degrees of lung injury were assessed 2 days later. RESULTS: Endothelial dysfunction in the pulmonary artery was significantly attenuated in rabbits treated with EPCs, whereas the endothelium-independent relaxation responses were not different. Expression of inducible nitric oxide synthase was suppressed in the pulmonary artery of EPC-treated animals. Infiltration of leukocytes in the lung parenchyma was significantly reduced after EPC transplantation. EPCs also decreased water content, hyaline membrane formation, and hemorrhage in lungs. CONCLUSION: The authors demonstrated that autologous transplantation of EPCs preserves pulmonary endothelial function and maintains the integrity of pulmonary alveolar-capillary barrier. Transplantation of EPCs can be a novel cell-based, endothelium-targeted therapeutic strategy for prevention and treatment of ALI/ARDS.

Prolonged use of high-dose morphine impairs angiogenesis and mobilization of endothelial progenitor cells in mice.

BACKGROUND: Morphine is one of the most commonly prescribed analgesics for treating wound pain. Using a mouse model of excisional wound injury, we determined the effects of high-dose morphine on angiogenesis and mobilization of endothelial progenitor cells. METHODS: An excisional wound was created on mice treated with placebo or morphine (20 mg/kg, i.p. injection for 14 days). Wound healing was compared by measuring the final-to-initial wound area ratio. Generation of superoxide anions in the wound was determined by luminol-enhanced chemiluminescence. Circulating mononuclear cells were isolated and measured for endothelial progenitor cell (defined as CD34+/CD133+ cell) counts. In vivo and in vitro measurements of angiogenesis after morphine treatment were performed using the Matrigel assay. RESULTS: Mice treated with morphine had reduced wound closure and higher wound superoxide ions concentrations than control mice. Morphine reduced the number of postwound circulating endothelial progenitor cells. Matrigel assay showed impaired angiogenesis in animals and reduced capillary tube formation in cultured endothelial cells treated with morphine. CONCLUSION: High-dose morphine impaired angiogenesis, increased systemic oxidative stress, and impaired mobilization of endothelial progenitor cells. This study emphasizes the potential detrimental effect of high-dose morphine on angiogenesis after systemic administration.

Epigallocatechin-3-gallate inhibits the early stages of Japanese encephalitis virus infection.

Epigallocatechin-3-gallate (EGCG), a green tea catechin, shows broad sepectrum antiviral activity against many RNA and DNA viruses. This study investigated the antiviral efficacy of EGCG against Japanese encephalitis virus (JEV), a zoonotic flavivirus in Southeast Asia and the Western Pacific region. EGCG concentration-dependently reduced CPE, sub-G1 phase, and virus yield of infected cells with different JEV strains at different MOIs. The antiviral activity of EGCG against JEV in different assays declined in the following order: virus yield (IC50 of 7.0 µM) > virus attachment (IC50 of 7.9 µM) > virus entry (IC50 of 9.4 µM) > receptor binding and post-entry. However, EGCG had no virucidal effect on the infectivity of JEV particles. The results indicated that antiviral mechanism of EGCG against JEV was associated with blocking the early steps of JEV infection. The study suggests EGCG as a lead compound for developing broad-spectrum antiviral agents.

Estimation of the depth of left-sided double-lumen endobronchial tube placement using preoperative chest radiographs.

BACKGROUND: Accurate placement of the double-lumen endobronchial tube (DLETs) is essential for optimal gas exchange during one-lung ventilation. The present study was designed to estimate the insertion depth of left-sided DLET using a preoperative chest radiograph. METHODS: Forty-five patients who underwent thoracic operations requiring intubation of a DLET were studied. The distance between the cephalic edge of the sixth cervical vertebra and the carina of the trachea (Dc-c) was measured from the anterior-posterior view of preoperative chest radiograph. After the tube was positioned in the main bronchus, a fiberoptic bronchoscope was introduced into the tracheal lumen to ensure the appropriate position of the DLET. Simple regression analysis for the insertion depth of the DLETs and Dc-c was performed. RESULTS: There was a highly significant correlation between the insertion depth of the DLET and both the Dc-c (y = 0.5304x + 19.646) and the body height (y = 0.1022x + 10.525), with P < 0.001 and P < 0.01, respectively. CONCLUSIONS: To get the distance from the cephalic edge of the 6th cervical vertebra to the Dc-c from the chest radiograph preoperatively would be helpful for the evaluation of the proper insertion depth of the placement of DLET.

Continuous cerebrospinal fluid drainage using a lumbar subarachnoid catheter for cerebrospinal fluid rhinorrhea after functional endoscopic sinus surgery.

Anesthesiologists are frequently consulted for performing lumbar cerebrospinal fluid (CSF) drainage to facilitate surgery or manage complications. Functional endoscopic sinus surgery (FESS) is a common treatment for chronic sinus diseases. Cerebrospinal fluid (CSF) leakage is a serious complication following FESS and is typically treated with an endonasal free or rotational mucoperichondrial flap. Continuous drainage of CSF with a lumbar subarachnoid catheter has been used in patients who have undergone neurosurgery but it is seldom used in the treatment of post-FESS CSF rhinorrhea. We present a 71-year-old male patient who suffered from CSF rhinorrhea after FESS, and was treated successfully with continuous lumbar CSF drainage. We are of the opinion that continuous CSF drainage with a lumbar subarachnoid catheter is an effective and safe modality of treatment for post-FESS CSF leakage.

Inhibition of ATP-sensitive potassium channels attenuates propofol-induced vasorelaxation.

BACKGROUND: Infusion of propofol often causes significant vasodilation, which is followed by a profound drop in blood pressure. However, the exact underlying molecular mechanisms of this clinically important phenomenon remain unclear. OBJECTIVE: To determine the biological role of endothelium in propofol-induced vasorelaxation and the underlying molecular mechanisms of this response in the rat aorta. DESIGN, SETTING AND SUBJECTS: Ex vivo assessment of vasomotor function in rat aortic rings, with or without endothelium, after addition of propofol or etomidate. In vivo randomised study of haemodynamic changes in Sprague Dawley rats after administration of propofol, with or without prior infusion of a K(ATP) antagonist. In vitro measurement of intracellular calcium in cultured vascular smooth muscle cells (VSMC) treated with propofol. The experiments were conducted in a research laboratory at the National Cheng Kung University, Taiwan, from August 2008 to July 2009. INTERVENTIONS: Changes in isometric tension of precontracted rat aortic rings were recorded after cumulative addition of propofol (3-300µM). An ATP-sensitive potassium (K(ATP)) channel blocker, glibenclamide (10µM), was incubated in the organ bath before the addition of propofol. Haemodynamic changes after intravenous administration of propofol in the presence or absence of PNU-37883A (a vascular-specific K(ATP) channel blocker) were recorded in anaesthetised rats. Alterations in intracellular calcium and ATP levels in cultured VSMC treated with propofol were measured. RESULTS: Compared with etomidate, propofol induced a significant concentration-dependent vascular relaxation response that was independent of the presence of endothelium. The relaxation response was almost completely abolished by K(ATP) channel antagonism. Levels of intracellular calcium were significantly attenuated in cultured VSMC treated with propofol (10mM). Pre-treatment with PNU- 37883A significantly attenuated propofol-induced hypotension in anaesthetised rats. CONCLUSIONS: Development of hypotension after systemic administration of propofol is mainly caused by its direct relaxation effect on vascular smooth muscle. This response is mainly mediated by activation of K(ATP) channels.

Severe bronchospasm during laryngeal mask airway placement in an infant.

A 35-day-old male infant was scheduled for bilateral inguinal herniorrhaphy. No history of recent upper airway infection or other reactive respiratory disease was noted before anesthesia. Breath holding was noted immediately after laryngeal mask airway (LMA) insertion. Removal of the LMA and positive pressure ventilation via face mask did not solve the problem. On suspicion of laryngospasm, tracheal intubation facilitated by muscule relaxant was performed. However, when the patient was ventilated, high airway pressure, absence of chest wall movement and elevated end-tidal CO2 were noted. Despite visual confirmation of correct placement of tracheal tube, oxygen desaturation and bradycardia developed rapidly. After deepening the inhalational anesthesia of sevoflurane and concomitant administration of intravenous lidocaine, the patient's respiratory condition turned for the better and became compliable. Respiratory dysfunction may be caused by severe bronchospasm induced by placement of the LMA. The pathophysiology and risk factors of bronchospasm related to the LMA placement are discussed in the text.

The effects of intrathecal tramadol on spinal somatosensory-evoked potentials and motor-evoked responses in rats.

UNLABELLED: Tramadol has been proven to exert a local anesthetic-type effect on peripheral nerves in both clinical and laboratory studies. In this study, we evaluated the effects of tramadol on sensory and motor neural conduction when administered intrathecally in the rat. Tramadol (0, 1, or 2 mg) was administered through an intrathecal catheter. Spinal somatosensory-evoked potentials (SSEPs) were recorded at the thoracolumbar junction after stimulation of the sciatic nerve. An evoked compound muscle action potential (CMAP) was recorded in the intrinsic muscles of the foot in response to electric stimulation of the lower thoracic (T1213) interspinous space. Both SSEP and CMAP were obtained before drug application as the pretreatment baseline and at 5, 15, and 30 min after treatment, and at 30- or 60-min intervals thereafter for another 4.5 h. SSEP was averaged from 20 responses, whereas CMAP was obtained from a single stimulation. Reproducible SSEPs and CMAP were consistently recorded in all rats. Intrathecal tramadol dose-dependently reduced the amplitude and delayed the latency in both SSEPs and CMAP. Generally, the suppressive effects occurred immediately after injection and recovered over 2 h. Combined administration with 20 micro g of intrathecal naloxone did not attenuate the inhibition of spinal SSEPs. We conclude that intrathecal tramadol causes a dose-related suppressive effect on both sensory and motor neural conduction in the spinal cord. IMPLICATIONS: Spinal somatosensory-evoked potentials and evoked compound muscle action potential were used to evaluate the effects of intrathecal tramadol on sensory and motor neural conduction. Intrathecal tramadol dose-dependently reduced the amplitude and delayed the latency of both spinal somatosensory-evoked potentials and compound muscle action potential. These results indicate that tramadol exerts a dose-related central neural blockade.

A long-term analysis of the spinal somatosensory evoked potential of rats with sciatic constriction injury.

BACKGROUND: This study was undertaken to evaluate the long-term effect of a peripheral neuropathic pain model, chronic constriction injury (CCI) of the sciatic nerve, through analyses of electrophysiologic change, sciatic nerve function, and pain behavior. METHODS: CCI of the sciatic nerve was induced in twelve rats as described by Bennett and Xie. Three parameters were monitored: spinal somatosensory evoked potential (SSEP) elicited by supramaximal stimulation of the posterior tibial nerve and recorded from the thoracolumbar junctional space; thermal hyperalgesia assessed by measuring paw withdrawal latency (PWL); and sciatic function index (SFI). All the values of these parameters were obtained before the CCI procedure (day 1 as a preoperative baseline, and again on days 5, 12, 19, 26, 33, 47, 61, 75, and 89). SSEP was also measured 3 hr after the CCI operation. Data were also obtained from contralateral limbs. RESULTS: All rats with CCI developed thermal hyperalgesia on day 5, as indicated by a significant reduction in PWL in the CCI limbs and a deterioration of the SFI compared with baseline values. These effects persisted to day 89. In the electrophysiologic study, 3 hrs after the CCI operation, the amplitude significantly decreased and latency significantly increased in all SSEP recordings. The changes persisted and showed no further statistically significant deterioration or recovery. The data demonstrated that the major electrophysiologic change after a constriction injury was the loss of conduction ability across the injury site in the fast-conducting fibers, but in the slow-conducting fibers the conduction ability was still preserved, which occurred immediately after the operation and persisted consistently for 89 days in the rats with behavior manifestations of neuropathic pain. CONCLUSIONS: Our findings suggest that SSEP is simple to obtain and sensitive in the acute phase of electrophysiological changes, but is limited for long-term evaluation after CCI.