Midazolam-induced athetoid movements of the lower extremities during epidural anesthesia reversed by physostigmine

Midazolam is a short-acting, water-soluble benzodiazepine used for induction and maintenance of general anesthesia and as an adjunct to regional anesthesia. This substance produces several types of untoward reactions, including agitated excitement, mental confusion, and uncooperativeness, as well as dystonic extrapyramidal reactions, such as tonic clonic movements, muscle tremor, and athetoid movements. We describe two patients who developed akinesthesia with athetoid movements of the lower extremities after receiving midazolam as a premedication and as an adjunct to epidural anesthesia. These movements occurred with a sensory level of T₄ as assessed by pinprick, even though the patients were unable to move their lower extremities.     

High thoracic epidural anesthesia does not inhibit sympathetic nerve activity in the lower extremities.

BACKGROUND: Sympathetic nerve activity was recorded in the leg during high thoracic epidural anesthesia with a segmental sensory blockade of the upper thoracic dermatomes to test the hypothesis that the sympathetic blockade accompanying thoracic epidural anesthesia includes caudal parts of the sympathetic nervous system. METHODS: Experiments were performed on 10 patients scheduled for thoracotomy. An epidural catheter was inserted at the T3-T4 or T4-T5 interspace. In the main protocol (seven patients), blood pressure, heart rate, and skin temperature (big toe, thumb) were continuously monitored, and multiunit postganglionic sympathetic nerve activity was recorded with a tungsten microelectrode in a muscle-innervating fascicle of the peroneal nerve. After baseline data collection, muscle sympathetic nerve activity was recorded for an additional 45-min period after epidural injection of 4-6 ml bupivacaine, 5 mg/ml. In an additional three patients, the effects of thoracic epidural anesthesia on skin-innervating sympathetic nerve activity were qualitatively assessed. RESULTS: Activation of thoracic epidural anesthesia caused no significant changes in peroneal muscle sympathetic nerve activity (n = 7), blood pressure, or heart rate. Skin temperature increased significantly in the hand 15 min after activation of the blockade, from 32.7 +/- 2.4 degrees C to 34.4 +/- 1.5 degrees C (mean +/- SD), whereas no changes were observed in foot temperature. The sensory blockade extended from T1 (C4-T2) to T8 (T6-T11). CONCLUSIONS: A high thoracic epidural anesthesia with adequate sensory blockade of upper thoracic dermatomes may be achieved without blockade of caudal parts of the sympathetic nervous system. This finding differs from that of earlier studies that used indirect methods to evaluate changes in sympathetic nerve activity.     

The characteristics of epidural anesthesia in operations on the aorta and vessels of the lower extremities]

Under study were the parameters of microcirculation in 84 patients operated on the vessels in the aorto-ilio-femoral zone, in 33 patients operated on the vessels in the femoro-popliteal zone. In all of them epidural anesthesia was used. In 25 patients operations on the aorta and main vessels were fulfilled under conditions of epidural anesthesia with catheterization of the epidural space at two levels. The dynamics of microcirculation parameters allows to state that the epidural anesthesia with catheterization of the epidural space at two levels is more rational for patients in operations on the vessels in the aorto-ilio-femoral zone since it gives adequate anesthesia during operation and better tissue blood flow in lower extremities.     

A case of cardiac arrest with coronary artery spasm during lumbar epidural anesthesia

A 61-year-old man underwent arthroscopic surgery for internal derangement of the knee joint under epidural anesthesia. Epidural catheterization was performed at the L 2-3 interspace. Operation was started with 10 ml of 1.5% lidocaine. Then 12 ml of 0.375% bupivacaine was added to epidural space. Twenty minutes thereafter, electrocardiogram demonstrated marked elevation of ST segment and atrio-ventricular dissociation, followed by cardiac arrest. Cardiopulmonary resuscitation was started immediately and after 25 minutes normal sinus rhythm was restored. The patient recovered with no neurological sequelae. Coronary angiogram examination was performed but no significant stenosis of coronary artery was observed. Coronary artery spasm caused by lumbar epidural anesthesia was suspected.     

Shivering during epidural anesthesia

The authors tested the hypothesis that during epidural anesthesia: 1) shivering-like tremor is primarily normal thermoregulatory shivering; 2) hypothermia does not produce a subjective sensation of cold; and 3) injectate temperature does not influence tremor intensity. An epidural catheter was inserted into ten healthy, nonpregnant volunteers randomly assigned to skin-surface warming below the T10 dermatome (warmed group) or no extra warming (unwarmed group). Each volunteer was given two 30-ml epidural injections of 1% lidocaine (16.0 +/- 4.7 degrees C and 40.6 +/- 0.7 degrees C at the catheter tip), in random order separated by at least 3 h. Skin-temperature gradients (forearm-fingertip) and tympanic membrane and average skin temperatures were recorded; significant vasoconstriction was prospectively defined as a gradient greater than or equal to 4 degrees C. Integrated electromyographic (EMG) intensity was recorded from four upper-body muscles. Overall thermal comfort was evaluated using a visual analog scale. Tympanic membrane temperatures decreased significantly in the unwarmed group (n = 6). Tremor occurred following ten of 12 injections in unwarmed volunteers, but only following one of eight injections in the warmed group. Integrated EMG intensity did not differ significantly following epidural injection of warm and cold lidocaine: tremor started when tympanic membrane temperature decreased about 0.5 degrees C and continued until central temperature returned to within 0.5 degrees C of control. Tremor always was preceded by hypothermia and vasoconstriction in the arms. Thermal comfort increased in both groups after epidural injection, with maximal comfort occurring at the lowest tympanic temperatures.(ABSTRACT TRUNCATED AT 250 WORDS)     

A case of coronary artery spasm during epidural anesthesia with continuous infusion of propofol

A 50-year-old male patient was scheduled for left partial pulmonary resection and biopsy. The patient had neither complication nor history of ischemic heart disease. After arriving in the operation room, an epidural catheter was inserted into the epidural space at the T 4-5 intervertebral space. Anesthesia was induced with intravenous propofol 100 mg, fentanyl 100 microgram and vecuronium 6 mg and then a double lumen endotracheal tube was inserted. Anesthesia was maintained with O2 and air (FIO2 0.3-1.0), continuous infusion of propofol, intermittent intravenous administration of fentanyl and epidural injection of 1% lidocaine. Forty-five minutes after the start of operation, ECG showed an elevation of ST segment and soon it passed into ventricular tachycardia and ventricular fibrillation. The patient was treated with cardiopulmonary resuscitation. Fifteen minutes later, ECG returned to sinus rhythm but the elevation of ST segment remained. We considered that these cardiac events were due to coronary spasm, and started continuous infusion of nitroglycerin and nicorandil. One hour later, ST segment returned to normal. The possible inducing factors in this case were altered balance between sympathetic and parasympathetic nervous activity caused by infusion of propofol and epidural block, and alpha-stimulation caused by ephedrine.     

连续腰麻与连续硬膜外麻醉用于高危老年患者下肢手术的比较

目的探讨连续腰麻用于应用于高危老年患者下肢手术的可行性。方法40例拟行下肢手术的老年患者,年龄68～101岁,ASAⅢ～Ⅳ级,按手术种类配对,患者随机分为硬膜外麻醉组(EA组)、连续腰麻醉组(CSA组),每组20例。EA组按常规行硬膜外麻醉,CSA组按常规行连续腰麻。于麻醉前(T0,基础值)、麻醉平面满意时(T1)、切皮后1h(T2)、术毕时(T3)抽取动脉血测乳酸浓度,常规监测动脉压(ABP)、心率(HR)、脉搏氧饱和度(SPO2),记录两组患者辅用麻黄素、氟芬合剂的情况。结果CSA组麻醉前、后各时点的MBP、HR、SpO2均无显著性变化;EA组硬膜外用药后,MBP、HR明显下降(P<0.05)。从T0至T2时段,EA组有98%的患者需辅用麻黄素,显著高于CSA组(15%)(P<0.01),EA组麻黄素用量[(30.5±3.1)mg]显著高于CSA组[(4.1±0.5)mg](P<0.01)。EA组有40%的患者术中需辅用氟芬合剂,显著高于CSA组(15%)(P<0.05)。在T1、T2、T3各时点EA组动脉血乳酸浓度均高于CSA组(P<0.05)。CSA组术后未见连续腰麻相关并发症。结论与硬膜外麻醉相比,连续腰麻麻醉效果确切,对循环干扰小,非常实用于高危老年患者的下肢手术。     

Patient-controlled sedation during epidural anesthesia

The purpose of this study was to evaluate the feasibility and advantages or disadvantages, if any, of patient-controlled sedation compared with sedation administered by the anesthesiologist during surgical epidural anesthesia. Forty patients were divided at random into two groups with 20 patients in each group. Patients in group 1 received 0.5-1.0 mg intravenous midazolam and 25-50 micrograms intravenous fentanyl in increments administered by the anesthesiologist to achieve intraoperative sedation; patients in group 2 self-administered a mixture of midazolam (0.5 mg) and fentanyl (25 micrograms) in increments using an Abbott Lifecare PCA infuser to achieve sedation. Demographics of the patients, the types of surgery performed, doses of midazolam and fentanyl administered in a given period of time, and the level of sedation maintained during epidural anesthesia and surgery were similar in both groups. Patients in the self-administered group, however, rated their level of comfort during anesthesia and surgery higher than did those in the anesthesiologist-controlled sedation group. This could have been due to a positive psychological effect produced by allowing patient to feel that they have some control over their situation. The findings of this study indicate that patient-controlled sedation using a combination of midazolam and fentanyl is a safe and effective technique that provides intraoperative sedation ranked better by patients than that provided by anesthesiologists using the same drugs. More studies are, however, needed to determine the best choice of drug(s), the doses, the lock-out intervals, and the possible use of continuous infusion with patient-controlled sedation.     

Motor blockade during epidural anesthesia

The effects of lumbar epidural anesthesia (LEA) on a previously described test of function of the rectus abdominalis muscle (the RAM-test) were compared with the effects of LEA on the Bromage test of muscle power in the hips and legs in 20 women having elective cesarean sections under LEA using 0.5% bupivacaine with epinephrine 1:200,000. The results showed no statistically significant correlation between the two tests. We conclude that zones of differential somatic motor blockade are present during LEA and that in obstetrics the RAM-test is the more appropriate test for evaluating the effects of LEA on somatic motor function. Use of the RAM-test is suggested in situations where one is interested in motor function of the abdominal wall muscles under LEA.     

Intraoperative awareness during propofol anesthesia with epidural anesthesia

This report describes a case of awareness and recall during propofol anesthesia combined with epidural anesthesia in a 32-year-old woman scheduled for a resection of left ovarian tumor. After induction, anesthesia was maintained with propofol and epidural anesthesia. About one hour into maintenance, the patient was moving with haemodynamic signs suggesting inadequate analgesia. Immediately after extubation, the patient could recall the abdomen being touched during laparotomy. This case indicates that even if appropriate dose of propofol is administrated, intraoperative awareness may occur especially with inadequate analgesia.     

A case of AV block (Mobitz II type) during recovery from general anesthesia combined with epidural anesthesia

A 59-year-old female underwent total hysterectomy for cancer of the corpus uteri. Epidural catheterization was performed at T 12/L 1 interspace. Anesthesia was induced with propofol (80 mg) and vecuronium (6 mg) and maintained with nitrous oxide (66%) and sevoflurane (0.8-1.5%) in oxygen. Six ml of 1.5% lidocaine containing 1: 200,000 epinephrine was injected intermittently through the epidural catheter for epidural anesthesia. Surgery was performed uneventfully. During her recovery from anesthesia, Mobitz II heart blocks and bradycardia were observed when the discharge in the oral cavity was aspirated. The AV blocks disappeared within 2 min, but similar arrhythmia was observed when the discharge in the oral cavity was aspirated again. Stimulation of the trachea by a suction drainage reversed the arrhythmia to the normal sinus rhythm. The trachea was extubated, and arrhyththmia was no longer observed in the operating room, but when the patient vomited, the next morning, bradycardia occurred and she lost consciousness. Two weeks later, there were no abnormal findings in echocardiography, Holter ECG, master-double ECG, and scintigraphy of the heart. It is likely that in this patient stimulation of the oral cavity by suction drainage and vomiting triggered vagovagal reflex, causing the AV block.     

Ergot-induced vasospasm of the lower extremities treated with epidural anaesthesia.

No reliable treatment to reverse severe ergot-induced vasopasm is available. A case of ergotamine-induced vasospasm of the lower extremities is presented. A combined treatment of vasodilators, infusion of low molecular dextran and high epidural anaesthesia apparently prevented extremity gangrene from occurring.     

Laparoscopic pelvic lymphadenectomy during epidural anesthesia

This report describes the perioperative management of a 70-year-old man undergoing bilateral pelvic lymphadenectomy. Because of concerns regarding this patient's high risk for myocardial ischemia, the four-hour surgical procedure, which included the formation of pneumoperitoneum, was performed during epidural anesthesia with minimal sedation. The anesthetic implications of pneumoperitoneum during regional anesthesia are discussed.     

A case of post-spinal tinnitus which improved after undergoing epidural anesthesia

A 34-year-old woman suffering from post-spinal tinnitus for 8 years was scheduled for a cesarean section under epidural anesthesia selected to prevent a deterioration of this condition due to a possible decrease in the cerebrospinal fluid level. Unexpectedly, the tinnitus disappeared completely after the epidural injection of 2% lidocaine 27 ml and following continuous epidural infusion. It is conceivable that moderate quantities of local anesthetics into the epidural space might have acted as an effective method similar to that of epidural physiologic saline injection in order to improve the cerebrospinal pressure.