Purpose: Whether or not right and left stellate ganglion blocks (SGB) affect blood pressure (BP) and heart rate (HR) differently has been controversial. The aim of this study was to analyze BP and HR changes after lar...Purpose: Whether or not right and left stellate ganglion blocks (SGB) affect blood pressure (BP) and heart rate (HR) differently has been controversial. The aim of this study was to analyze BP and HR changes after large numbers of right or left SGBs. Methods: A total of 16,404 right SGBs and 13,766 left SGBs were performed with 6 ml of 1% mepivacaine using the anterior paratracheal approach at C6. Changes in systolic BP and HR 30 min after SGBs were compared to the baseline values. Results: Systolic BP decreased by 25 to 49 mmHg in 10.93% and more than 50 mmHg in 0.67% of 16,404 right SGBs. Those percentages were significantly higher than corresponding percentages;8.43% and 0.49% of 13,766 left SGBs (P < 0.0001 and P < 0.05, respectively). On the other hand, systolic BP increased by 25-49 mmHg in 5.74% and more than 50 mmHg in 0.52% of left SGBs, and in 4.15% and 0.18% of right SGBs (P < 0.0001and P < 0.0001 between left and right SGBs, respectively). Right SGB caused marked reduction in HR (greater than 30 beats/min), more than left SGB (4.22% versus 2.70%, P Conclusions: Both right and left SGBs could produce clinically significant hypertension and hypotension, and also severe bradycardia. However, right SGB produces a higher incidence of significant reductions in systolic BP and HR, compared to left SGB. On the other hand, left SGB produces a significant increase in systolic BP compared to right SGB. Those differences likely stem from the hemispheric asymmetry in autonomic cardiovascular control.展开更多
In this paper,we propose an arbitrary decode-forward single-relay scheme for finite blocklength polar codes,which can be applied to the general symmetric discrete memoryless relay channel with orthogonal receiver comp...In this paper,we propose an arbitrary decode-forward single-relay scheme for finite blocklength polar codes,which can be applied to the general symmetric discrete memoryless relay channel with orthogonal receiver components.The relay node decodes the received message.The relay node selectively re-encodes the message and transmits it to the destination node.Furthermore,in order to minimize the upper-bound of the block error probability,we propose a selection strategy to decide the proper re-encoded bit set by the relay.Simulation results are presented to illustrate the improvement in decoding performance of the proposed scheme compared to conventional relay schemes in both additive white Gaussian noise(AWGN)channel and Rayleigh fading channel(RFC).展开更多
In this paper, we study the performance of block diagonalization (BD) scheme for a downlink multiuser multi-input multi-output (MIMO) system with imperfect channel state information (CSI). At each mobile user, informa...In this paper, we study the performance of block diagonalization (BD) scheme for a downlink multiuser multi-input multi-output (MIMO) system with imperfect channel state information (CSI). At each mobile user, information about the channel is obtained by applying the minimum mean-square-error (MMSE) channel estimation method. The channel state information is fed back to the base station through error-free uplink channels. A theoretical analysis is performed showing that channel estimation errors contribute to co-channel interferences thus deteriorating sum rate capacity. Computer simulations are performed to evaluate the impact of channel estimation errors on the sum rate capacity. The results show that if the MSE of the channel estimation is not less than 10-2, the impact of channel estimation errors is significant and cannot be neglected. To combat this adverse effect, a proper transmit power level is required for the training signals.展开更多
Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime b...Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime block coding （SSTBC） in multiple antenna systems. At the transmitter, the primitive data are serial to parallel converted to multiple data streams, and each stream is rotated in constellation. Then Walsh codes are used to spread each symbol to all antenna space in a space-time block. The signals received from all receiver antennas are combined with the maximum ratio combining （MRC）, equalized with linear equalizer to eliminate the inter-code interference and finally demodulated to recover to transmit data by using the one-symbol maximum likelihood detector. The proposed scheme does not sacrifice the spectrum efficiency meanwhile maintains the transceiver with low complexity. Owing to the transmission symbols of different transmit antennas passing through all the spatial subchannels between transceiver antenna pairs, the system obtains the partial additional space diversity gain of all spatial paths. It is also shown that the diversity gain is better than the previous space-time block coding （STBC） schemes with full transmission rate.展开更多
<b>Background:</b> Peripheral block techniques for total hip arthroplasty have been used as an analgesic strategy, only a few studies described it as an anesthetic technique, so the perioperative performan...<b>Background:</b> Peripheral block techniques for total hip arthroplasty have been used as an analgesic strategy, only a few studies described it as an anesthetic technique, so the perioperative performance and safety are poorly studied. <b>Methods:</b> 78 total hip arthroplasties were prospectively observed in our hospital. Divided into 2 groups: 1) General anesthesia;and 2) Lumbar sacral plexus block anesthesia. Variables measured in both groups were: demographics, conversion to general anesthesia, total opioid doses, surgical time, blood loss, postoperative pain, use and total dose of vasopressors drugs, transfusion and ICU transfer needs, postoperative ambulation time, and length of hospital stay. T student and chi-square tests were used upon the case. A significant difference was considered when a value of p < 0.05 was obtained. Descriptive statistics were performed in frequency, percentages, variance and standard deviation. <b>Results:</b> 3 patients (7.3%) anesthetized with combined lumbar sacral plexus block were converted to general anesthesia. When comparing peripheral nerve block and general anesthesia, less intraoperative (p = 0.000) and postoperative (p = 0.002) opioid consumption were noted, less postoperative pain in PACU (p = 0.002) and in the first 24 hours (p = 0.005), as well as earlier onset of ambulation (p = 0.008) and shorter hospital stay (p = 0.031). <b>Conclusions:</b> In our study, the lumbar and sacral plexus block anesthesia technique provided anesthetic conditions to perform hip joint arthroplasty and it was proved to be advantageous in comparison to general anesthesia.展开更多
文摘Purpose: Whether or not right and left stellate ganglion blocks (SGB) affect blood pressure (BP) and heart rate (HR) differently has been controversial. The aim of this study was to analyze BP and HR changes after large numbers of right or left SGBs. Methods: A total of 16,404 right SGBs and 13,766 left SGBs were performed with 6 ml of 1% mepivacaine using the anterior paratracheal approach at C6. Changes in systolic BP and HR 30 min after SGBs were compared to the baseline values. Results: Systolic BP decreased by 25 to 49 mmHg in 10.93% and more than 50 mmHg in 0.67% of 16,404 right SGBs. Those percentages were significantly higher than corresponding percentages;8.43% and 0.49% of 13,766 left SGBs (P < 0.0001 and P < 0.05, respectively). On the other hand, systolic BP increased by 25-49 mmHg in 5.74% and more than 50 mmHg in 0.52% of left SGBs, and in 4.15% and 0.18% of right SGBs (P < 0.0001and P < 0.0001 between left and right SGBs, respectively). Right SGB caused marked reduction in HR (greater than 30 beats/min), more than left SGB (4.22% versus 2.70%, P Conclusions: Both right and left SGBs could produce clinically significant hypertension and hypotension, and also severe bradycardia. However, right SGB produces a higher incidence of significant reductions in systolic BP and HR, compared to left SGB. On the other hand, left SGB produces a significant increase in systolic BP compared to right SGB. Those differences likely stem from the hemispheric asymmetry in autonomic cardiovascular control.
基金supported in part by the National Natural Science Foundation of China under Grant 92067202,Grant 62071058.
文摘In this paper,we propose an arbitrary decode-forward single-relay scheme for finite blocklength polar codes,which can be applied to the general symmetric discrete memoryless relay channel with orthogonal receiver components.The relay node decodes the received message.The relay node selectively re-encodes the message and transmits it to the destination node.Furthermore,in order to minimize the upper-bound of the block error probability,we propose a selection strategy to decide the proper re-encoded bit set by the relay.Simulation results are presented to illustrate the improvement in decoding performance of the proposed scheme compared to conventional relay schemes in both additive white Gaussian noise(AWGN)channel and Rayleigh fading channel(RFC).
文摘In this paper, we study the performance of block diagonalization (BD) scheme for a downlink multiuser multi-input multi-output (MIMO) system with imperfect channel state information (CSI). At each mobile user, information about the channel is obtained by applying the minimum mean-square-error (MMSE) channel estimation method. The channel state information is fed back to the base station through error-free uplink channels. A theoretical analysis is performed showing that channel estimation errors contribute to co-channel interferences thus deteriorating sum rate capacity. Computer simulations are performed to evaluate the impact of channel estimation errors on the sum rate capacity. The results show that if the MSE of the channel estimation is not less than 10-2, the impact of channel estimation errors is significant and cannot be neglected. To combat this adverse effect, a proper transmit power level is required for the training signals.
基金This project was supported by the National Science Foundation of China (60496314)
文摘Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime block coding （SSTBC） in multiple antenna systems. At the transmitter, the primitive data are serial to parallel converted to multiple data streams, and each stream is rotated in constellation. Then Walsh codes are used to spread each symbol to all antenna space in a space-time block. The signals received from all receiver antennas are combined with the maximum ratio combining （MRC）, equalized with linear equalizer to eliminate the inter-code interference and finally demodulated to recover to transmit data by using the one-symbol maximum likelihood detector. The proposed scheme does not sacrifice the spectrum efficiency meanwhile maintains the transceiver with low complexity. Owing to the transmission symbols of different transmit antennas passing through all the spatial subchannels between transceiver antenna pairs, the system obtains the partial additional space diversity gain of all spatial paths. It is also shown that the diversity gain is better than the previous space-time block coding （STBC） schemes with full transmission rate.
文摘<b>Background:</b> Peripheral block techniques for total hip arthroplasty have been used as an analgesic strategy, only a few studies described it as an anesthetic technique, so the perioperative performance and safety are poorly studied. <b>Methods:</b> 78 total hip arthroplasties were prospectively observed in our hospital. Divided into 2 groups: 1) General anesthesia;and 2) Lumbar sacral plexus block anesthesia. Variables measured in both groups were: demographics, conversion to general anesthesia, total opioid doses, surgical time, blood loss, postoperative pain, use and total dose of vasopressors drugs, transfusion and ICU transfer needs, postoperative ambulation time, and length of hospital stay. T student and chi-square tests were used upon the case. A significant difference was considered when a value of p < 0.05 was obtained. Descriptive statistics were performed in frequency, percentages, variance and standard deviation. <b>Results:</b> 3 patients (7.3%) anesthetized with combined lumbar sacral plexus block were converted to general anesthesia. When comparing peripheral nerve block and general anesthesia, less intraoperative (p = 0.000) and postoperative (p = 0.002) opioid consumption were noted, less postoperative pain in PACU (p = 0.002) and in the first 24 hours (p = 0.005), as well as earlier onset of ambulation (p = 0.008) and shorter hospital stay (p = 0.031). <b>Conclusions:</b> In our study, the lumbar and sacral plexus block anesthesia technique provided anesthetic conditions to perform hip joint arthroplasty and it was proved to be advantageous in comparison to general anesthesia.
