一种具有高信噪比的脉搏波光电传感器的研制

目的：探讨研制一种生理信号光电传感器。方法：利用光电传感器检测通过指端毛细血管后的光强度的变化，将光信号转换成电信号，再经过电信号1/V转换、放大、滤波处理。结果：获得了清晰稳定的指端容积脉搏波。结论：高信噪比的光电传感器可用作于临床监测和生理信号分析处理系统。     

Epidural block for obstetrics: Comparison of bolus injection of local anesthetic with gravity flow technique

Study Objective: To test the hypothesis that slow administration of local anesthetic into the epidural space by gravity flow reduces the incidence of signs and symptoms of unintended injection.

Design: Prospective, randomized study.

Setting: Teaching hospital.

Patients: 600 ASA physical status I and II parturients scheduled for labor and delivery or elective cesarean section.

Interventions: After identification of the epidural space with pulsations of an air-fluid column, parturients for vaginal delivery (n = 380) were randomized to receive a test dose of 3 ml 3% 2-chloroprocaine with epinephrine 20 μg, two doses of 7 ml bupivacaine 0.03 % with sufentanil 1 μg/ml and epinephrine 2 μg/ml by either gravity flow (Group 1) given over 30 seconds or by bolus injection (Group 2) given over 5 seconds through the epidural needle; parturients for Cesarean delivery (n = 220) were randomized to receive a test dose and two doses of 6 ml lidocaine 2 % with sufentanil 1 μg/ml and epinephrine 2 μg/ml by either gravity flow or by bolus injection through the epidural needle. Changes in maternal heart rate (HR) and blood pressure, signs of intravascular injection, and adverse effects of epidural bupivacaine-sufentanil were recorded after each dose.

Measurements and Main Results: Gravity flow administration (Group 1) was associated with a smaller increase in mean maternal HR (p < 0.001), less hypotension (p < 0.01), sedation (p < 0.01), nausea (p = 0.01), and segmental spread (p < 0.0001) than were corresponding doses given by traditional bolus injection (Group 1) for vaginal or Cesarean deliveries. The incidence of systemic toxicity was zero of 300 (0%) with gravity flow and 4 of 300 (1.3%) by bolus injection, p = 0.12, Fisher's exact test. No patient in either group had an accidental intrathecal injection.

Conclusion: Gravity flow administration of local anesthetic-opioid solution during epidural block for obstetrics was associated with fewer signs of systemic drug absorption and cardiovascular perturbations than was the traditional bolus injection. This study supports the current opinion that slow administration of local anesthetic during epidural black contributes to fewer adverse events.     

Cerebral blood flow, cerebral metabolic rate of oxygen and relative CO2 reactivity during neurolept anaesthesia in patients subjected to craniotomy for supratentorial cerebral tumours

In 10 patients subjected to craniotomy for supratentorial cerebral tumours in neurolept anaesthesia, cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured twice peroperatively by a modification of the Kety & Schmidt technique, using 133Xe. The relative CO2 reactivity was assessed indirectly as the % change of the arteriovenous oxygen difference (AVDO2) per mm change in PaCO2. The patients were premedicated with diazepam 10-15 mg perorally. For induction, thiopentone 4-6 mg/kg, droperidol 0.2 mg/kg and fentanyl 5 micrograms/kg were used, and for maintenance N2O 67% and fentanyl 4 micrograms/kg/h. During the first flow measurement the median and range of CBF was 30 ml/100 g/min (range 17-45), of AVDO2 8.0 vol % (range 4.1-9.5), and of CMRO2 2.28 ml O2/100 g/min (range 1.57-2.84). During the second CBF study, AVDO2 increased to 9.3 vol % (range 3.4-11) (P less than 0.05), and CMRO2 increased to 2.51 ml O2/100 g/min (range 1.88-3.00) P less than 0.05, while CBF was unchanged. The CO2 reactivity was present in all studies, median 1.8%/mmHg (range 0.5-15.1). The correlation coefficients between jugular venous oxygen tension/saturation, respectively, and CBF were high at tensions/saturations exceeding 4.0 kPa and 55%, indicating that hyperperfusion is easily unveiled by venous samples from the jugular vein during this anaesthesia.     

紧闭式氧化亚氮麻醉方法的探讨

２５例选择期手术病人采用紧闭式氧化亚氮麻醉方法，术中持续监测呼气末氧和氧化亚氮浓度，脉搏血氧饱和度和呼吸循环指标，术中观察紧闭式麻醉后呼吸末氧化亚氮，氧浓度变化，结果：紧闭式麻醉１，２，３ｈ后氧化亚氮浓度分别为５２．７％，５６％，６４．９％，氧浓度为４２．１％，３４．４％，３０．８％，随麻醉时间的延长，气道压力先降后回升，约３ｈ恢复至紧闭麻醉前的水平，紧闭式麻醉前后在本组观察时间内动脉血气分析提示     

Alfentanil or fentanyl during isoflurane–based anaesthesia for day–care knee arthroscopy?

Forty patients agreed to participate in a study to compare whether fentanyl or alfentanil used as analgesic is associated with quicker recovery following anaesthesia for outpatient arthroscopy procedure. Psychomotor tests including choice reaction time (CRT), perceptive accuracy test (PAT) and finger tapping test (FTT) were done prior to induction of anaesthesia with propofol (2–3 mg–kg^-1). Patients were then divided into two groups: Group F (fentanyl) received 0.1 mg fentanyl prior to start of surgery and thereafter 0.05 mg every 30 min during the procedure. Group A (alfentanil) received 0.5 mg alfentanil prior to the onset of surgery and 0.25 mg every 15 min thereafter. Anaesthesia was then maintained using isoflurane (0.5–2%) in oxygen and air (Fio₂ 0.33) during spontaneous respiration with a face mask in a Bain's system. Psychomotor tests were repeated every 45 min postoperatively. Clinical recovery, visual analogue pain intensity score (VAS) and time to discharge home were also assessed by a nurse blind to the method used. Patients in Group A returned to baseline values on the FTT after 90 min while those in Group F did not return to baseline values until 135 min after the end of the operation. Clinical recovery and time to discharge home ("home ready") were also significantly longer in Group F. There was no difference in recovery as seen in the PAT and CRT between the groups. Also, there was no difference in the incidence of side effects and the pain intensity (VAS) scores were similar in the two groups at all time periods. We conclude that recovery following alfentanil is quicker compared to fentanyl when anaesthesia is based on isoflurane.     

2-chloroprocaine antagonism of epidural morphine analgesia

Background: 2-chloroprocaine (2-CP) used for lumbar epidural anesthesia (LEA) reportedly decreases the efficacy of epidural morphine (EM) administered for post-cesarean section (CS) analgesia. The amount of supplemental i.v. morphine self-administered by the patient via the patient-controlled analgesia device (PCA) is used to study the interaction between EM and 2-CP.
Methods: Forty-two patients scheduled for elective CS were randomly divided into 3 equal groups, and received 2-CP, 2-CP+epinephrine (Epi, 5 μg ml^-1) or 2% lidocaine (Lido) with Epi for LEA. All patients received 5 mg EM and i.v. PCA morphine for postoperative pain. Cumulative amount of i.v. morphine used in the first 24 hours as well as the amount of the drug used during each 2-h period were noted. Nonparametric analysis of variance and Chi-squared analysis were used for statistical comparisons.
Results: The mean cumulative 24-h i.v. PCA morphine requirement in the 2-CP, 2-CP+Epi and Lido+Epi groups respectively was 20.5±24, 33.1.5±27 and 4.07±6.3 (mean±SD). The Lido+Epi group used significantly less morphine ( P = 0.01) compared to either of the 2-CP groups with no significant difference between the 2-CP groups. The maximum i.v. PCA morphine use occurred in the first 4 hours following surgery in all three groups.
Conclusion: Analgesic efficacy of EM is decreased when 2-CP is used for LEA compared to when Lido+Epi is used.     

A Comparative Study of the Percutaneous versus Intraoral Technique for Mental Nerve Block

Objective: Mental nerve block is frequently used to aid repair of facial lacerations; both percutaneous and intraoral approaches to blocking this nerve are used, but have never been compared. The authors compared the two techniques for pain of administration and effectiveness of anesthesia. Methods: A prospective, randomized, single-blind, crossover study was conducted using ten healthy volunteers aged 22 to 33 years. Patients having prior experience with mental nerve blocks, lidocaine allergy, active oral/facial infection, or previous facial fractures were excluded. Bilateral mental nerve blocks were done using intraoral technique on one side and percutaneous technique on the other. Both techniques were used by the same investigator and were carried out with 27-gauge needles and 2.5 mL of 2% buffered lidocaine at room temperature injected over 20 seconds. The oral mucosa was topically anesthetized with viscous lidocaine for 1 minute prior to intraoral injection. The orders of the blocks and sides of the face anesthetized were randomized. Subjective and objective pain (visual-analog scale), efficacy (anesthesia of lower lip), time to onset, and duration of anesthesia were evaluated. Results: The intraoral technique was subjectively less painful than the percutaneous approach in nine of ten subjects (p = 0.02). Scores on the visual-analog pain scale were significantly lower for the intraoral technique (p = 0.03). Intraoral injection produced lower-lip anesthesia in 10/10 subjects versus 7/10 for percutaneous (p = 0.25). Times to onset (approximately 1–2 minutes) and durations of anesthesia (approximately one hour) were similar for the two techniques. Conclusion: The intraoral approach to the mental nerve block with adjunctive topical anesthesia was subjectively and objectively less painful than the percutaneous approach without adjunctive anesthesia. While the intraoral approach had a greater efficacy of lower-lip anesthesia and a longer duration of action, these differences were not statistically significant.     

Lokalrezidive von Weichteilsarkomen an Extremitäten und Rumpf

Soft tissue sarcomas (STS) tend to recur locally. In a series of 140 patients operated on during the past two decades with STS of the extremities and trunk, prognostic factors influencing local recurrence were determined. Statistical significance was evaluated for the quality of surgical resection (P<0.001), regional positive lymph nodes (P=0.03), and adjuvant radiotherapy (P=0.01) [for resection without wide margins (R1) and low-grade (G3) tumors]. In 1988, the surgical procedure was standardized. After 1987, local recurrence decreased significantly (P < 0.001). In subfascial tumors, local recurrence occurred far less in cases of compartmental resection than with wide excision. These data indicate that the course of patients with STS can be beneficially influenced by optimal therapy. Resection with wide margins in all three dimensions is the aim of sarcoma surgery. Postoperative radiation therapy is indicated in the case of R1 resection.

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Lokalrezidive von Weichteilsarkomen an Extremitäten und Rumpf

Zusammenfassung Weichteilsarkome neigen zur Ausbildung von Lokalrezidiven. In einer Studie von 140 Patienten der letzten 20 Jahre mit Sarkomen an Extremitäten und Rumpf wurde untersucht, welche Faktoren das Auftreten von Lokalrezidiven beeinflussen. Statistische Signifikanz ergab sick fur die Qualität der chirurgischen Re sektion (R) (p<0,001), den regionalen Lymphknotenstatus (p=0,03) sowie eine adjuvante Strahlentherapie (p=0,01) [bei marginal resezierten (RI), niedrig differenzierten (G3) Tumoren]. 1988 wurde das chirurgische Vorgehen standardisiert. In der Zeit danach traten signifikant weniger Rezidive auf als davor (p < 0,001). Bei subfaszialer Lage traten Rezidive nach Kompartmentresektion wesentlich seltener auf als nach weiter Resektion. Der Krankheitsverlauf von Weichteilsarkomen ist also durchaus therapeutisch beeinflußbar. Ein dreidimensional weiter Sicherheitsabstand ist das entscheidende Therapieziel, eine Bestrahlung in R1-Situationen indiziert.