Oligogenic determination of morphine analgesic magnitude: A genetic analysis of selectively bred mouse lines

Two ongoing selective breeding projects have produced mice that display divergent analgesic responses to morphine. These two projects have selected for similar phenotypes: high and low levorphanol analgesia (HAR/LAR lines; Portland, OR) and high and low swim stress-induced analgesia (HA/LA lines; Jastrzebiec, Poland). Evidence suggests genetic commonalities between mice of the two projects. Using a Mendelian breeding protocol, we have recently found that one or two genetic loci predominantly determine the high morphine analgesia exhibited by HA mice. In the present study we demonstrate that the differential morphine analgesia (5 mg/kg. i.p.) displayed by HAR and LAR mice is similarly oligogenic, predominantly determined by two unlinked loci. A complementation analysis, in which the analgesic responses to morphine of the recessive homozygotes of each project (HAR and HA) were compared to those of their hybrid offspring (HAR x HA), revealed that different genetic loci have been fixed in each project. An intriguing bimodal distribution was observed in the HAR x HA population: Some HAR x HA hybrids displayed greater morphine analgesia than either HAR or HA mice, whereas others displayed minimal analgesia. LAR x LA hybrids displayed less analgesia than either LAR or LA mice. The analgesic responses of HAR x LA and LAR x HA mice were comparable to those of their low-line parents. These findings indicate not only that different loci were responsible for producing high morphine responders in each selection project but that these distinct loci can interact synergistically to produce superhigh and superlow responders.     

Epidural anesthesia in anin vitro fertilization and embryo transfer program

Objectives To investigate the potential advantages of epidural anesthesia in an in vitro fertilization and embryo transfer program.Study Design Between January 1991 and December 1992, 148 infertile patients underwent transvaginal ultrasound guided oocyte retrieval. A total of 44 patients (group A) had 50 retrievals under epidural anesthesia, and 104 patients (group B, control group) 112 retrievals under intravenous sedation (propofol) with mask-assisted ventilation (nitrous oxide).Results In group A satisfactory anesthesia was achieved in 49 of the 50 cases (98%); one patient required additional intravenous administration of propofol owing to extreme anxiety. No complications were observed. Adversely, in group B nausea was observed in 16 cases (14%) and nausea and vomiting in 7 cases (6%). In group A the fertilization, cleavage and pregnancy rates were 67.2%, 92% and 20% respectively, while in group B the rates were 69.3%, 93% and 19.6% respectively; the differences are not statistically significant.Conclusions Epidural anesthesia is an effective method for transvaginal oocyte retrieval but does not improve the treatment outcome as compared to an intravenous sedation with mask-assisted ventilation using propofol and nitrous oxide.     

Piriformis pyomyositis mimicking epidural abscess in a parturient

A case is presented of a patient who developed fever, leukocytosis, severe back pain, local overlying spinal tenderness, and left leg weakness on the fifth day postpartum. The patient had epidural anaesthesia for ten hours duration, before and during a forceps delivery. Computerized axial tomography (CT) and magnetic resonance imaging (MRI) of the pelvis and lumbar spine revealed swelling of the left iliacus and piriformis muscles, but no epidural abscess. A diagnosis of isolated piriformis pyomyositis with secondary sciatic nerve irritation was made, and the patient was treated with intravenous antibiotics, non-steroidal anti-inflammatory agents, and morphine analgesia. She made a full, uneventful recovery within 50 days, and was discharged requiring no medications.     

Anaesthetic management of a child with Bartter’s syndrome

We report the anaesthetic management of an eight-year-old asthmatic boy with Bartter’s syndrome who had bilateral orchidopexy with caudal epidural analgesia. Bartter’s syndrome is a rare congenital disorder characterized by hypokalaemic hypochloraemic metabolic alkalosis, hyperaldosteronism, hyperreninaemia and hyperplasia of the juxtaglomerular apparatus of the kidneys. Characteristically, although these patients are normotensive they may be hypovolaemic. They may have unstable baroreceptor responses and show marked resistance to vasopressors. Hence, fluid, acid-base and electrolyte imbalances along with haemodynamic instability pose particular problems in their anaesthetic management. Previous case reports have described the management of these patients with general anaesthesia, our patient had his orchidopexy with caudal epidural analgesia using plain bupivacaine 0.5%. The patient was haemodynamically stable throughout surgery and was comfortable with caudal analgesia as the sole anaesthetic. Hypovalaemia, acid-base status and electrolyte imbalance were treated before instituting caudal epidural analgesia. We present this case report which describes the anaesthetic considerations in the light of the pathophysiology of Bartter’s syndrome.     

Calcified convexity dura mater and acute epidural haematoma mimicking calcified chronic subdural haematoma

We report a patient with calcification of the convexity dura mater and an acute epidural haematoma. CT revealed a calcified layer between the haematoma and brain parenchyma, which mimicked acute bleeding into a calcified chronic subdural haematoma. The appearance of a calcified haematoma does not always mean a chronic lesion, and that emergency operation should not be foregone, when there is a history of acute head trauma and progressive impairment of consciousness.     

食管癌术后一次性硬膜外注射和肌肉注射镇痛法的比较

目的：确定硬膜外一次性镇痛法对食管癌病人术后的镇痛效果和减少并发症的意义。方法：９３ 例病人随机分成实验组（ Ｔ 组,５１ 例） 和对照组（ Ｃ 组,４２ 例） , Ｔ 组于手术结束缝合皮肤切口时经硬膜外导管于 Ｔ６ － ７ 水平注射吗啡１ ｍｇ 加１ ％ 普鲁卡因１０ ｍｌ, Ｃ 组用阿片类药物肌肉注射镇痛。结果： Ｔ 组病人术后疼痛明显减轻,各种并发症显著下降。结论：硬膜外一次性镇痛效果确切,操作方便,副作用少,对降低术后心肺并发症很有意义,尤其对年龄大、心肺功能差的病人较适合。     

胸段硬膜外麻醉对神经肽Y的影响

为探讨胸段硬膜外麻醉对患者血浆ＮＰＹ的影响,本文采用放射免疫分析法测定了３１ 例择期上腹部手术病人胸段硬膜外麻醉前后血浆ＮＰＹ的含量。结果显示：麻醉后平均动脉压较麻醉前显著下降（ Ｐ＜０－０１） ,血浆ＮＰＹ则无显著变化（ Ｐ＞ ０－０５）。提示患者处于硬膜外麻醉状态下体内ＮＰＹ 含量的变化与交感神经系统调节具有一定的关系。     

麻黄素并吗啡硬膜外注射的术后镇痛效果

①目的　探讨麻黄素并吗啡硬膜外注射的术后镇痛效果。②方法　对１２６ 例泌尿外科开放手术后的病人进行间断硬膜外腔注射吗啡（２ｍ ｇ）、麻黄素（２０ｍ ｇ）,观察其镇痛效果,并与４０ 例单用吗啡（ ２ｍ ｇ）者进行对照。③结果　吗啡、麻黄素的镇痛作用强而持久,一次用药有效时间为（２８．４±３．５）ｈ,较对照组的（１８．１±２．６）ｈ 明显延长（ｔ＝ １７．１,Ｐ＜ ０．０１）。未见出现血压波动者。④结论　吗啡加麻黄素硬膜外腔注射是安全、长效的术后镇痛方法,特别适用于术后留置导尿或尿流改道的泌尿外科开放手术。     

大鼠闭合性硬膜外球囊扩张脑损伤模型的建立

为建立闭合性脑硬膜外占位性颅脑损伤的大鼠模型,利用5F 漂浮导管置脑硬膜外模拟占位,按球囊注入水量和持续时间分组。观察各组动物的死亡率,存活鼠的颅内压、脑含水量的变化以及血肿形成、组织受损的情况。结果显示:球囊越大,持续时间越长,损伤越大;存活鼠颅内压及脑水含量均增加,神经机能受损,并有血肿形成和受压区坏死;上述变化随占位时间延长和受压程度的加重而加重。提示该脑损伤模型简单可行、可重复,能较好地反映硬膜外占位性脑损伤的病理分级,且经济实用     

Postoperative nausea and vomiting in children using patient-controlled analgesia: the effect of prophylactic intravenous dixyrazine

BACKGROUND: Although patient-controlled analgesia (PCA) with morphine provides a high degree of satisfactory postoperative analgesia in children, it is often associated with a high incidence of postoperative nausea and vomiting (PONV). Our aim in this study was to evaluate the prophylactic effect of dixyrazine, a phenothiazine with proven anti-emetic properties. METHODS: The incidence of nausea and vomiting was studied in 60 children using PCA after major surgery. The patients were randomised to receive either dixyrazine 0.25 mg kg-1 or placebo on the induction of anaesthesia in a double-blind, placebo-controlled design. The anaesthetic technique was standardised. The PCA pump was programmed to deliver bolus doses of morphine of 20 micrograms kg-1 with a continuous background infusion of 8-10 micrograms kg-1 h-1. Nausea, vomiting, sedation and pain scores were noted every 3 h for a period of 24 h. RESULTS: The morphine consumption of morphine was the same in both groups. During the stay in the recovery room the incidence of vomiting was 3% in the dixyrazine group compared to 30% in the placebo group (P < 0.05). On the ward, 57% versus 83% of the children vomited (P < 0.05). Rescue antiemetics were significantly lower, 30%, in the dixyrazine group compared to 60% in the placebo group (P < 0.05). Higher sedation scores were recorded for the dixyrazine group in the recovery room. No other adverse effects were found. CONCLUSION: A significant number of children using PCA with morphine after major surgery experience PONV. Although prophylactic dixyrazine reduces the incidence and severity of vomiting, the incidence still remains high.