Mean effective volume of local anesthetics by nerve conduction technique.

BACKGROUND: This study aimed to investigate whether nerve conduction could be used to objectively evaluate mean effective volume of 1.5% lidocaine after subparaneural or extraparaneural injection. METHODS: Twenty patients undergoing unilateral foot or ankle surgery were randomized into either subparaneural or extraparaneural injection group, and ultrasound-guided continuous popliteal sciatic nerve block was performed. The action potential amplitude of the distal gastrocnemius muscle was monitored. The time of anesthesia onset and dosage of lidocaine were recorded when amplitude declined to 0.5 mV. The operative analgesic effect, score of numeric rating scales, patient's satisfaction, and movement or sensation were recorded during or after surgery. RESULTS: Preoperative dose of local anesthetics (10.7±1.6 vs. 16.2±1.2 mL) and the time of onset (19.4±3.3 vs. 30.4±2.5 min) reduced significantly in the subparaneural group (P<0.05). The intra-operative analgesic effect (1.2±0.422 vs. 1.3±0.483) and the score of resting numeric rating scales (0.6±1.0 vs. 1.9±2.1 and 0.4±0.7 vs. 1.2±1.1) 24 and 48 h after surgery were comparable between groups, but the subparaneural group had markedly lower scores of activity numeric rating scales (0.3±0.6 vs. 2.1±2.0, 0.7±1.2 vs. 2.2±1.9 and 0.5±0.8 vs. 1.5±1.2) at 6, 24 and 48 h, and significantly higher satisfaction (9.7±0.5 vs. 8.8±0.8) (P<0.05). There were no obvious symptoms of movement or sensation within 3 days in two groups. CONCLUSIONS: The nerve conduction can be used to objectively evaluate the mean effective volume of 1.5% lidocaine in different injection groups, and subparaneural injection has more advantages as compared to extraparaneural injection for continuous popliteal sciatic nerve block.

Two different placement paths in popliteal fossa with a novel nerve block needle for postoperative analgesia after foot and ankle surgery.

BACKGROUND: Previous studies have documented that single injection nearby the sciatic nerve bifurcation would influence the anesthesia and analgesia effect. But this is uncertain for preoperative continuous popliteal sciatic nerve block. This trial was conducted to compare two paths (proximal to the bifurcation and at the bifurcation) of ultrasound-guided continuous popliteal sciatic nerve block in foot and ankle surgery. METHODS: Forty recruited objects were randomly assigned to receive ultrasound-guided continuous popliteal sciatic nerve block at the puncture path proximal to the nerve bifurcation either at the nerve bifurcation. Subjects received an injection using a novel nerve block needle with external indwelling cannula guided by ultrasound invented by the corresponding author. The external indwelling cannula was inserted for postoperative analgesia. The primary outcome was NRS scores (at rest and during movement) times at 24 hours after surgery. The secondary outcomes included the measurements related to the performance of the nerve block and efficacy of analgesia, such as anesthesia effect grade, grade of nausea and vomiting, case number of patients with cannula leaking, occlusion or slipping, patient satisfaction, etc. RESULTS: During the surgery, six subjects in the proximal group needed additional analgesic, significantly different from one in the at bifurcation group (P<0.05). There was significant difference on anesthesia effect rating, 1.6±0.8 in the proximal group and 1.1±0.4 in another (P<0.05). The proximal group got 2.1±1.6 of NRS on rest at 24 hours and 1.7±1.5 at 48 hours, and the at bifurcation group got 0.9±1.4 at 24 hours and 0.7±1.1 at 48 hours (P<0.05). The proximal group got more PCA times during 6-24 hours and 24-48 hours and lower satisfaction scores. CONCLUSIONS: Continuous popliteal sciatic nerve block at nerve bifurcation could receive better analgesia effect and more patients' satisfaction, rather than proximal to the bifurcation.

Clinical application of a novel endoscopic mask: a randomized controlled, multi-center trial in patients undergoing awake fiberoptic bronchoscopic intubation.

BACKGROUND: Awake fiberoptic bronchoscopic tracheal intubation is usually regarded as an effective method in the management of predicted difficult airway. Hypoxia during awake nasal fiberoptic bronchoscopic intubation leads to discontinuation of the procedure, prolonged manipulation time and increased risk of severe complications. The main aim of the study was to test whether the novel endoscopic mask is helpful for hypoxia during the intubation. METHODS: This was a randomized, controlled, multi-center study. 55 patients were recruited, but one patient was lost to follow-up. Finally, 54 patients (19 man and 35 women) were analyzed. After entering the operating room, nasal catheter oxygen-providing was given in the control group, and the treatment group received endoscopic mask oxygen-providing, with a flow rate of 3 L/min, lasting into the end of the intubation. Primary outcomes included mean arterial pressure, heart rate, minimum pulse oxygen saturation and incidence of pulse oxygen saturation ≤ 90%. Secondary outcomes included number of intubation attempts and time to intubation. All outcomes were finally measured. RESULTS: Minimum pulse oxygen saturation during awake nasal fiberoptic bronchoscopic tracheal intubation was significantly higher in the endoscopic mask intubation group (91.7% ± 4.7%) than that the nasal catheter intubation group (87.6% ± 8.2%, P = 0.031. Furthermore, the incidence of pulse oxygen saturation ≤ 90% was significantly lower in the endoscopic mask intubation group (20.0%, 5/25) than that in the nasal catheter intubation group (51.7%, 15/29, P = 0.037). But mean arterial pressure of during intubation was significantly higher in the endoscopic mask group (100.0 ± 13.3 vs 90.3 ± 21.8, P = 0.049). In addition, there were no differences in the number of intubation attempts (P = 0.45) or time to intubation between the two groups (P = 0.38). CONCLUSIONS: The endoscopic mask was safely used in awake fiberoptic bronchoscopic tracheal intubation, with advantages of stable blood pressure and potential prevention of desaturation. Beginners for the intubation procedure and patients at high risk of hypoxia could benefit from the use of the endoscopic mask. TRIAL REGISTRATION: Trial registration: www.chictr.org.cn . Registration No.: ChiCTR-TRC-13004086. Date of Registration: 8th, Sep, 2013.

Clinical application of a novel endoscopic mask: A randomized controlled trial in aged patients undergoing painless gastroscopy.

Background: Desaturation during painless gastroscopy in aged patients leads to discontinuation of the procedure, prolonged manipulation time and increased risk of severe complications. An endoscopic nasal mask was designed to control hypoxia during the above procedures. A randomized trial was performed to test whether the novel endoscopic mask is helpful for hypoxia during painless gastroscopy in aged patients. Methods: In this randomized, controlled trial, 141 aged patients undergoing painless gastroscopy were randomized into nasal catheter group (69 patients) and endoscopic mask group (65 patients). Primary outcomes were minimum pulse oxygen saturation and incidence of pulse oxygen saturation ≤ 90%. Results: Finally, 134 aged patients were analyzed, including 69 patients in nasal catheter group and 65 patients endoscopic mask group. The minimum pulse oxygen saturation (96.4% ± 4.8%) was higher in the aged endoscopic mask group than in the aged nasal catheter group (94.3% ± 5.6%, P = 0.0075). The incidence of pulse oxygen saturation ≤ 90% did not significantly differ between the endoscopic mask group and nasal catheter group (6.2% VS 15.9%, P = 0.07). There were no severe adverse events in either groups. Conclusion: The endoscopic mask was safely used in aged patients during painless gastroscopy under propofol sedation and significantly improved the minimum pulse oxygen saturation without increasing time to examination or recovery time.

Ultrasound-guided continuous femoral nerve block vs continuous fascia iliaca compartment block for hip replacement in the elderly: A randomized controlled clinical trial (CONSORT).

BACKGROUND: Continuous femoral nerve block and fascia iliaca compartment block are 2 traditional anesthesia methods in orthopedic surgeries, but it is controversial which method is better. The objective of this study was to compare the practicality, efficacy, and complications of the 2 modalities in hip replacement surgery in the elderly and to assess the utility of a novel cannula-over-needle set. METHODS: In this prospective, randomized controlled clinical investigation, 60 elderly patients undergoing hip replacement were randomly assigned to receive either continuous femoral nerve block or continuous fascia iliaca compartment block. After ultrasound-guided nerve block, all patients received general anesthesia for surgery and postoperative analgesia through an indwelling cannula. Single-factor analysis of variance was used to compare the outcome variables between the 2 groups. RESULTS: There was a significant difference between the 2 groups in the mean visual analog scale scores (at rest) at 6 hours after surgery: 1.0 ±â€Š1.3 in the femoral nerve block group vs 0.5 ±â€Š0.8 in the fascia iliaca compartment block group (P < 0.05). The femoral nerve block group had better postoperative analgesia on the medial aspect of the thigh, whereas the fascia iliaca compartment block group had better analgesia on the lateral aspect of the thigh. There were no other significant differences between the groups. CONCLUSIONS: Both ultrasound-guided continuous femoral nerve block and fascia iliaca compartment block with the novel cannula-over-needle provide effective anesthesia and postoperative analgesia for elderly hip replacement patients.

Self-homodyne free-space optical communication system based on orthogonally polarized binary phase shift keying.

A self-homodyne laser communication system based on orthogonally polarized binary phase shift keying is demonstrated. The working principles of this method and the structure of a transceiver are described using theoretical calculations. Moreover, the signal-to-noise ratio, sensitivity, and bit error rate are analyzed for the amplifier-noise-limited case. The reported experiment validates the feasibility of the proposed method and demonstrates its advantageous sensitivity as a self-homodyne communication system.

Effects of Postoperative Continuous Femoral Nerve Block Analgesia with Braun Continuous Peripheral Nerve Block Catheter Set versus Novel Needle-Over-Cannula after Total Knee Arthroplasty.

BACKGROUND: The aim of this study was to compare the novel needle-over-cannula vs. the Braun continuous peripheral nerve block catheter set (Contiplex A) in postoperative analgesics after total knee arthroplasty (TKA). MATERIAL AND METHODS: Sixty patients undergoing total knee arthroplasty were randomly assigned to Braun continuous peripheral nerve block catheter set group (Braun Group, n=30) or the novel needle-over-cannula group (Cannula Group, n=30). All the patients in the 2 groups received continuous femoral nerve block (CFNB) for postoperative analgesics. RESULTS: We found no significant difference in analgesic effect between the 2 groups. The time of catheter or cannula insertion was shorter in the Cannula Group than in the Braun Group. Four (13.32%) out of 30 patients had failed catheter insertions in the Braun Group compared to none in the Cannula Group. Twelve (46%) out of 26 patients in the Braun Group had serious local anesthetic leakage at puncture sites during 12 h compared to none in the Cannula Group. CONCLUSIONS: The novel needle-over-cannula is effective, convenient, and safe in CFNB after TKA.

New coherent laser communication detection scheme based on channel-switching method.

A new coherent laser communication detection scheme based on the channel-switching method is proposed. The detection front end of this scheme comprises a 90° optical hybrid and two balanced photodetectors which outputs the in-phase (I) channel and quadrature-phase (Q) channel signal current, respectively. With this method, the ultrahigh speed analog/digital transform of the signal of the I or Q channel is not required. The phase error between the signal and local lasers is obtained by simple analog circuit. Using the phase error signal, the signals of the I/Q channel are switched alternately. The principle of this detection scheme is presented. Moreover, the comparison of the sensitivity of this scheme with that of homodyne detection with an optical phase-locked loop is discussed. An experimental setup was constructed to verify the proposed detection scheme. The offline processing procedure and results are presented. This scheme could be realized through simple structure and has potential applications in cost-effective high-speed laser communication.