Systemic distribution of blood flow in swine while awake and during 1.0 and 1.5 MAC isoflurane anesthesia with or without 50% nitrous oxide

To examine the effects of isoflurane on systemic distribution of cardiac output, organ/tissue blood flow was measured in 11 isocapnic pigs using 15-micrometer diameter radionuclide-labeled microspheres injected into the left atrium. Measurements were made on each pig during five of the following six conditions; awake (control); 1.0 MAC (1.45% end-tidal)isoflurane anesthesia; 1.5 MAC (2.18% end-tidal) isoflurane anesthesia; 0.95% end-tidal isoflurane and 50% N2O anesthesia equivalent to 1.0 MAC; 1.68% end-tidal isoflurane and 50% N2O anesthesia equivalent to 1.5 MAC; and 50% N2O administration. The order of anesthetized steps was randomized. A period of 60 min was interposed between anesthetized steps to allow pigs to recover towards control values. Mean aortic pressure decreased in a dose-related manner during isoflurane anesthesia, whereas cardiac output decreased only during 1.5 MAC isoflurane anesthesia and heart rate remained unchanged. The addition of N2O attenuated the hypotensive effects of isoflurane and cardiac output was maintained near control values because of increased heart rate. Brain blood flow increased in a dose-dependent manner with isoflurane anesthesia, but myocardial blood flow exhibited a dose-related decrease. The addition of 50% N2O to maintain the same total MAC anesthesia resulted in a larger increase in brain blood flow especially at 1.5 MAC, while myocardial blood flow was maintained near control value. Rate-pressure product and myocardial blood flow at 1.5 MAC anesthesia were higher when N2O was used with isoflurane. While blood flow and fraction of cardiac output going to the adrenal glands were unaltered during isoflurane-N2O anesthesia, blood flow increased at 1.5 MAC isoflurane anesthesia. Splenic blood flow and splenic fraction of cardiac output were increased at both MAC levels of isoflurane as well as isoflurane-N2O anesthesia whereas blood flow to the stomach, small intestine, diaphragm, skeletal muscle, and adipose tissue decreased from control values. Renal, hepatic arterial, and cutaneous blood flow remained unaltered. Fifty percent N2O in the presence of a residual end-tidal isoflurane concentration of 0.20% caused heart rate to increase from control levels, while cardiac output and mean aortic pressure were unaltered. Brain blood flow increased by 27% above control values, but perfusion in the myocardium, adrenal glands, spleen, kidneys, liver, and skin was unchanged. Stomach, small intestine, skeletal muscle, and diaphragm blood flows decreased from control values, whereas perfusion of adipose tissue increased.     

Translation of the glenohumeral joint in patients with multidirectional and posterior instability: awake examination versus examination under anesthesia

The purpose of this study was to assist in establishing guidelines to determine the degree of shoulder instability, the value of awake clinical examination, and the value of examination under anesthesia (EUA). Forty-three patients with clinical diagnosis of multidirectional shoulder instability (MDI) and 28 patients with posterior instability underwent bilateral shoulder translation testing, both awake and while under anesthesia. Two surgeons using guidelines and translation grades developed by the American Shoulder and Elbow Surgeons examined each patient and assigned a single grade for the anterior, posterior, and inferior directions. A comparison of translational grade was performed with the use of Pearson chi2 and McNemar symmetry to determine association. The patients with MDI showed increased translation in the anterior, inferior, and posterior directions when the affected limb was compared with the noninvolved side in both preoperative examination and EUA. Furthermore, the patients with MDI showed increased anterior translation on the affected side during EUA compared with the clinical examination. Patients with posterior instability demonstrated increased anterior translation for both affected and noninvolved limbs during EUA. However, the posterior translation obtained before surgery did not change during EUA for both the affected and noninvolved limbs, and there was no side-to-side difference in posterior translation.     

Comparison of awake spinal with awake caudal anesthesia in preterm and ex‐preterm infants for herniotomy1

Background: Spinal anesthesia (SA) is widely used for awake regional anesthesia in ex‐preterm infants scheduled for herniotomy. Awake caudal anesthesia (CA) is suggested as an alternative approach for these patients and type of surgery. The aim of this study was to compare efficacy and complications of the two different techniques. Methods: Two historical populations of 575 ex‐preterm infants undergoing herniotomy under awake SA (n = 339; 1998–2001) and under awake CA (n = 236; 2001–2009) were investigated. Data are compared using t‐test and chi‐square tests (P < 0.05). Results: The SA group consisted of 339 patients, they were born after 32.0 (3.3) weeks of gestation on average with a mean birth weight of 1691 g (725). The CA group consisted of 236 patients born after 32.1 weeks (3.7) with a mean birth weight of 1617 g (726). At the time of operation, the total age was 41.37 (3.6) and 41.28 (4.0), respectively, for SA and CA patients, and the corresponding weights were 3326 (1083) g and 3267 (931) g for SA and CA patients, respectively. For SA, significantly more puncture attempts were needed (1.83 vs 1.44, P < 0.001). Surgery was performed under pure regional anesthesia in 85% (SA) and 90.1% (CA) (ns). A change to general anesthesia was necessary in 7.7% (SA) and 3.9% (CA) (ns). Overall, intra‐ and postoperative complications were not statistically different. Conclusions: Caudal anesthesia was shown to be technically less difficult than SA and to have a higher success rate. Its application as awake regional anesthesia technique in these patients seems more appropriate than SA.     

Whole-hand sensorimotor area: cortical stimulation localization and correlation with functional magnetic resonance imaging

OBJECT: The pli de passage moyen (PPM) is an omega-shaped cortical landmark bulging into the central sulcus. There has been considerable interest in the PPM given that hand motor and sensory tasks have been found on functional magnetic resonance (fMR) imaging to activate the structure. Note, however, that the cortical function subserved by the PPM is not completely understood. Finger and thumb function are somatotopically organized over the central area and encompass a larger cortical surface than the anatomical PPM. Therefore, a sensory or motor hand area within the PPM would be redundant with the somatotopically organized digit function in the primary sensorimotor cortex. In this study the authors aimed to clarify the function subserved by the PPM and further evaluate hand area function in the primary sensorimotor cortex. METHODS: To further elucidate the function subserved by the PPM, patients underwent cortical stimulation in the region of the PPM as well as fMR imaging-demonstrated activation of the hand area. Two separate analytical methods were used to correlate hand area functional imaging with whole-hand sensory and motor responses induced by cortical stimulation. RESULTS: A relationship of the anatomical PPM with cortical stimulation responses as well as hand fMR imaging activation was observed. CONCLUSIONS: A strong relationship was identified between the PPM, whole-hand sensory and motor stimulation responses, and fMR imaging hand activation. Whole-hand motor and whole-hand sensory cortical regions were identified in the primary sensorimotor cortex. It was localized to the PPM and exists in addition to the somatotopically organized finger and thumb sensory and motor areas.     

Translation of the glenohumeral joint in patients with anterior instability: awake examination versus examination with the patient under anesthesia.

Fifty patients with a clinical diagnosis of traumatic anterior shoulder instability underwent bilateral shoulder translation testing while both awake and under anesthesia. Each patient was examined by 2 surgeons following guidelines developed by the American Shoulder and Elbow Surgeons. A single translation grade was established for anterior, posterior, and inferior directions. A comparison of means was performed with a paired t test. The mean anterior translation grade was significantly higher on the affected side when compared with that of the unaffected side both during awake examination and during examination with the patient under anesthesia (EUA). Ipsilateral comparison revealed significantly greater translation for both affected and unaffected shoulders in anterior, posterior, and inferior directions during EUA than during awake examination. Side-to-side comparison of posterior and inferior translation was similar for both awake examination and EUA. Clinical translation testing was helpful in the diagnosis of anterior shoulder instability. Side-to-side differences were subtle while awake and more apparent during EUA. The usefulness of awake translation testing for traumatic anterior instability was not clearly demonstrated; however, EUA provides helpful information to confirm the direction and degree of instability.     

Perception-related modulations of local field potential power and coherence in primary visual cortex of awake monkey during binocular rivalry

Cortical synchronization at gamma-frequencies (35-90 Hz) has been proposed to define the connectedness among the local parts of a perceived visual object. This hypothesis is still under debate. We tested it under conditions of binocular rivalry (BR), where a monkey perceived alternations among conflicting gratings presented singly to each eye at orthogonal orientations. We made multi-channel microelectrode recordings of multi-unit activity (MUA) and local field potentials (LFP) from striate cortex (V1) during BR while the monkey indicated his perception by pushing a lever. We analyzed spectral power and coherence of MUA and LFP over 4-90 Hz. As in previous work, coherence of gamma-signals in most pairs of recording locations strongly depended on grating orientation when stimuli were presented congruently in both eyes. With incongruent (rivalrous) stimulation LFP power was often consistently modulated in consonance with the perceptual state. This was not visible in MUA. These perception-related modulations of LFP occurred at low and medium frequencies (< 30 Hz), but not at gamma-frequencies. Perception-related modulations of LFP coherence were also restricted to the low-medium range. In conclusion, our results do not support the expectation that gamma-synchronization in V1 is related to the perceptual state during BR, but instead suggest a perception-related role of synchrony at low and medium frequencies.     

全麻下听觉诱发电位指数和内隐记忆的关系

目的 研究全麻下异丙酚和吸入麻醉药对内隐记忆的作用,分析界定内隐异丙酚记忆消失时的界值。方法 60例患者行择期腹部及下肢手术。随机分为异氟醚、七氟醚、地氟醚、异丙酚,对照组5组(每组12例)。试验组按静脉药输入速度(8mg·kg-1·h-1、10mg·kg-1·h-1)及吸入药呼未浓度(0.8、1.0MAC),又分为2个亚组(每组6例)。对照组(12例)为术中清醒的硬膜外麻醉下手术患行。监测患者入室后、入睡后、指令反应消失后、插管后、切皮后、关腹膜时(手术结束前30min)的听觉诱发电位指数(AEI),调查患者术后8h模糊辩听率,测试方法和条件与试验各组完全一致。常规监测血液动力学指数。结果 AEI,各亚组麻醉诱导前后有显著性差异(P<0.05).在相同浓度下,吸入麻醉药组患音及其亚组间比较入睡后、插管后、切皮后、切口关闭时血液动力学参数无显著性差异(P>0.05)。静脉持续泵入异丙酚8mg·kg-1·h-1时、三种吸入麻醉药浓度为1.0MAC时,患者模糊辩听率明显低于空白对照组(P<0.05)。三种吸入麻醉药浓度为1.0MAC及异内酚8mg·kg1·h-1时,能使内隐记忆消失,推算内隐记忆消失的AEI界值为异丙酚15;异氟醚12;七氟醚13;地氟醚14.结论当AEI界值低于12时,认为内隐记忆消失。     

Intra-operative monitoring in scoliosis surgery with multi-pulse cortical stimuli and desflurane anesthesia

STUDY DESIGN: Prospective, observational study. SETTING: Country General Hospital, Singapore. OBJECTIVE: Intraoperative monitoring (IOM) with motor-evoked potentials (MEPs) assesses the integrity of cortical spinal tracts during scoliosis surgery. MEPs are sensitive to the effects of inhalational anesthetic agents. We evaluate the use of desflurane in combination with multipulse cortical stimulation in this study. METHODS: In all, 10 consecutive neurologically normal subjects underwent scoliosis surgery with desflurane anesthesia (0.5 maximum alveolar concentration) and five pulse cortical stimulation (250 Hz) from two stimulators in parallel configuration, delivering a maximum intensity of 160 mA. RESULTS: Consistent MEPs were obtained from the abductor hallucis and tibialis anterior in nine of ten and five of five of subjects, respectively. Baseline coefficients of variations were below 16% for both muscles. CONCLUSION: This combination of anesthetic and stimulation protocols is efficacious for IOM during spinal cord surgery. Our findings support the use of desflurane for successful acquisition of MEPs during scoliois surgery as an alternative anesthetic regime.     

Shikani喉镜与Airtraq喉镜用于颈椎活动受限患者清醒气管插管对比研究

目的 比较Shikani喉镜与Airtraq喉镜清醒气管插管在颈椎手术中的应用效果. 方法 选择ASA分级Ⅰ、Ⅱ级,拟全身麻醉下行前路或后路颈椎内固定术患者60例.按随机数字表法分为Shikani喉镜组(S组)和Airtraq喉镜组(A组),每组30例.记录入室15 min麻醉诱导前(T1)、麻醉诱导后插管前(T2)、插管即刻(T3)、插管后1 min(T4)及插管后3 min(T5)时的MAP、HR、气管插管的成功率、插管时间,评估患者对气管插管的耐受性、配合程度及满意度,观察术后咽喉损伤情况. 结果 与T1比较,A组T3～T5时点MAP升高、HR增快(P＜0.05).A组T3～T5时点MAP高于S组,HR快于S组(P＜0.05).S组插管时间短于A组[(15±4)s比(22±5)s],插管成功率高于A组(100％比90％)(P＜0.05).与A组比较,S组气管插管耐受性及满意度优于A组(P＜0.05),咽喉损伤的发生率也较A组少(P＜0.05). 结论 颈椎手术清醒诱导插管中,与Airtraq喉镜比较,Shikani喉镜可减少气管插管时心血管应激反应,提高插管成功率及患者的舒适度,缩短插管时间,降低咽喉损伤的发生率.     

Intrathecal catheterization and solvents interfere with cortical somatosensory evoked potentials used in assessing nociception in awake rats

We assessed the objective measurement of central sensitization processes in the awake rat after subcutaneous formalin with cortical somatosensory evoked potentials (CSEPs). Cranial extradural electrodes and intrathecal catheters were implanted in adult male Wistar rats. After 7 days of recovery, CSEPs were induced by electrical stimuli at the tail and recorded before/after the injection of 50 microL of 2% formalin into the hindpaw of rats for 1 h. The drug and tested vehicles were delivered intrathecally 5 min before the injection of formalin. The peak-to-peak amplitude of the P1-N1 (the early positive-negative sequence pair of CSEPs) and the baseline-to-peak amplitude of the N2 (the late negative component of CSEPs) were analyzed. We found that the amplitudes of both signals increased (154.3% +/- 10.9% and 168.7% +/- 9.8%, respectively) from 10 min after formalin injection to the end of the 60-min test period. Pretreatment with intrathecal ketorolac dose-dependently prevented the increases induced by formalin in both measured variables. Moreover, the increases in P1-N1 and N2 were markedly attenuated either by intrathecal polyethylene-10 tubing or by the solvents used for injection, thus indicating the need for distinguishing an impaired nociceptive signal from antinociception when the effects of drugs are evaluated.     

Total intravenous anesthesia with propofol, fentanyl and ketamine for carotid endarterectomy under somatosensory evoked potential monitoring--combination with intraoperative hypothermia]

We reported anesthetic management combined with hypothermia for carotid endarterectomy under somatosensory evoked potential monitoring. Anesthesia was induced by propofol, fentanyl and ketamine, and maintained by infusion of propofol and ketamine and intermittent injections of fentanyl. Perioperative hypothermia was induced by gradually reducing the temperature of a circulating water mattress underneath the body to 15 degrees C. Additionally, somatosensory evoked potential monitoring was performed and recordings were obtained immediately after induction of anesthesia, and before as well as during cross-clamping of the internal carotid artery. Rectal temperature was reduced to 33.7 degrees C when cross-clamping of carotid artery was carried out, but major changes between before and during the procedure was not observed. All procedures were done uneventfully and gradual rewarming was accomplished by electric blanket. No neurological deficits were observed following recovery from anesthesia. Total intravenous anesthesia with propofol, fentanyl and ketamine may be useful for carotid endarterectomy under hypothermia and somatosensory evoked potential monitoring. This method may provide neuronal protection against ischemia injuries induced by cross-clamping of the carotid artery.     

Laparoscopic cholecystectomy under neuraxial anesthesia compared with general anesthesia: Systematic review and meta-analyses

BackgroundPneumoperitoneum during laparoscopic cholecystectomy (LC) can cause hypercapnia, hypoxemia, hemodynamic changes and shoulder pain. General anesthesia (GA) enables the control of intraoperative pain and ventilation. The need for GA has been questioned by studies suggesting that neuraxial anesthesia (NA) is adequate for LC.Study objectiveTo quantify the prevalence of intraoperative pain and to verify whether evidence on the maintenance of ventilation, circulation and surgical anesthesia during NA compared with GA is consistent.DesignSystematic review with meta-analyses.SettingAnesthesia for laparoscopic cholecystectomy.PatientsWe searched Medline, Cochrane and EBSCO databases up to 2016 for randomized controlled trials that compared LC in the two groups under study, neuraxial (subarachnoid or epidural) and general anesthesia.MeasurementsThe primary outcome was the prevalence of intraoperative pain referred to the shoulder in the NA group. Hemodynamic and respiratory outcomes and adverse effects in both groups were also collected.Main resultsEleven comparative studies were considered eligible. The pooled prevalence of shoulder pain was 25%. Intraoperative hypotension and bradycardia occurred more frequently in patients who received NA, with a risk ratio of 4.61 (95% confidence interval [CI] 1.70–12.48, p = 0.003) and 6.67 (95% CI 2.02–21.96, p = 0.002), respectively. Postoperative nausea and vomiting was more prevalent in patients who submitted to GA. The prevalence of postoperative urinary retention did not differ between the techniques. Postoperative headache was more prevalent in patients who received NA, while the postoperative pain intensity was lower in this group. Performing meta-analyses on hypertension, hypercapnia and hypoxemia was not possible.ConclusionsNA as sole anesthetic technique, although feasible for LC, was associated with intraoperative pain referred to the shoulder, required anesthetic conversion in 3.4% of the cases and did not demonstrate evidence of respiratory benefits for patients with normal pulmonary function.     

在体膜片钳技术比较戊巴比妥钠和乌拉坦麻醉下初级体感皮质神经元的自发膜电位特性

目的 采用在体穿孔全细胞膜片钳技术,记录成年大鼠单个初级体感皮质(S1)神经元,比较戊巴比妥钠和乌拉坦麻醉下神经元的自发膜电位活动. 方法 成年雄性SD大鼠20只,通过腹腔注射戊巴比妥钠或乌拉坦进行麻醉,按麻醉注射药物不同分为戊巴比妥麻醉组和乌拉坦麻醉组(每组10只),将头部固定于立体定位仪上,待麻醉稳定后进行在体穿孔膜片钳记录. 结果 实验在戊巴比妥钠组和乌拉坦麻醉组中各记录了27个S1神经元.结果显示:戊巴比妥麻醉组和乌拉坦麻醉组神经元的静息膜电位[(-84±4)mV比(-82±4)mV,P＞0.05]、动作电位发放频率[(0.28±0.28) Hz比(0.33±0.34) Hz,P＞0.05]和动作电位幅度[(58±10) mV比(63±8) mV,P＞0.05]比较,差异均没有统计学意义;但是两种麻醉药物作用下,神经元的自发膜电位变化模式完全不同,戊巴比妥钠麻醉下只包括短的兴奋性突触后电位,膜电位的累计分布呈单峰,而乌拉坦麻醉下呈现去极化(UP)和超极化(DOWN)交替出现的膜电位振荡,且膜电位的累计分布呈明显的双峰. 结论 在戊巴比妥钠和乌拉坦作用下,初级体感皮质神经元的膜电位变化模式不同.     

Anesthetic management of awake off-pump coronary artery bypass grafting (ACAB) with remifentanil and thoracic epidural anesthesia

Two patients with total occlusion of the right internal carotid artery, were anesthetized for ACAB with remifentanil and thoracic epidural anesthesia. Case 1: A 71-year-old man with hypertension and diabetes mellitus underwent single-vessel ACAB under IV remifentanil analgesia, the dose of which was adjusted to 0.04-0.05 microg x kg(-1) x min(-1), along with an epidural infusion of 10 ml x hr(-1) of a mixture of 2% lidocaine and 2.5 microg x ml(-1) of fentanyl, the PaCO2 being maintained at 52-55 mmHg. When the patient felt pain, the remifentanil dose was elevated to 0.08 microg x kg(-1) x min(-1) and PaCO2 increased to 60 mmHg. Case 2: A 66-year-old man with rheumatoid arthritis underwent ACAB for two grafts. An intraaortic balloon pump (IABP) was inserted preoperatively. The anesthetic method used was the same as in case 1, except for an additional right femoral block to provide anesthesia for extraction of the saphenous vein. Remifentanil was infused at 0.05 microg x kg(-1) x min(-1) and PaCO2 maintained at 49-53 mmHg. In response to the patient's pain and movement, the remifentanil dose was increased to 0.07-0.10 microg x kg(-1) x min(-1) and PaCO2 to 60 mmHg.     

Comparison of radical retropubic prostatectomy under combined lumbar spinal and epidural anesthesia with that under combined general and epidural anesthesia

PURPOSE: To evaluate the efficacy of combined lumbar spinal and epidural (CLSE) anesthesia in retropubic radical prostatectomy. MATERIALS AND METHODS: Twenty consecutive patients who underwent radical retropubic prostatectomy by a single surgeon (H.K.) under CLSE anesthesia from July of 2003 to February of 2004 were selected as subjects. They were compared with 20 consecutive patients who underwent radical retropubic prostatectomy performed by the same surgeon under combined general and epidural (CGE) anesthesia from April to December of 2002. Both periods were carefully selected to exclude radical prostatectomies with intraoperative complications to evaluate genuine effects of anesthesia. For lumbar spinal anesthesia, 0.5% hyperbaric bupivacaine hydrochloride or 0.5% hyperbaric tetracaine hydrochloride (dissolved in a 10% glucose solution) was used. An epidural tube was inserted for both lumbar spinal anesthesia and general anesthesia mainly for the purpose of controlling a pain after operation. RESULTS: Intraoperative blood loss was significantly less in the CLSE anesthesia group compared with CGE anesthesia group (p = 0.024). Postoperative water drinking was started at 0.4 days (average) for CLSE anesthesia and at 1.1 days (average) for CGE anesthesia (p < 0.0001). Postoperative diet was begun at 0.7 days (average) for CLSE anesthesia and at 1.5 days (average) for CGE anesthesia (p < 0.0001). Compared with the CLSE anesthesia group, the mean of the highest intraoperative mean blood pressure was significantly higher in the CGE anesthesia group (p = 0.002). CONCLUSION: Intraoperative blood loss was less, intraoperative change in blood pressure was less and recovery of postoperative intestinal peristalsis was earlier in patients who underwent prostatectomy under CLSE anesthesia than in patients who underwent prostatectomy under CGE anesthesia. We believe that prostatectomy under CLSE anesthesia is more advantageous than prostatectomy under CGE anesthesia.     

Semi-automated,slow subcutaneous infusion anesthesia (SIA) with diluted mixtures of prilocaine and ropivacaine

In recent years it has been found that local anesthesia, which often suffices for surgery of the skin and superficial structures, can be adequately administered using large amounts of highly diluted anesthetic solutions combined with epinephrine. This has considerably increased application of local anesthesia in plastic surgery. Using one or more conventional infusion pumps for slow subcutaneous infusion anesthesia (SIA), we injected mixed anesthetic solutions painlessly and automatically into the subcutaneous layer. The local anesthetics used were equivalent mixtures of prilocaine and ropivacaine (Xylonest and Naropin); these were diluted with original Ringers solution containing epinephrine (1:1,000,000) in 500-ml bottles. The concentrations of the mixtures varied between 0.3% and 0.06% depending on the requirements of surgery. Routinely available 18- to 30-gauge needles were used. The speed of injection varied between 30 ml and 1500 ml per hour depending on the location, the requirements of surgery, and the needle size. Volumes usually ranged from 2 ml to 1000 ml depending on the concentrations. The maximum dose was approximately 4 mg of prilocaine and 2 mg/kg of ropivacaine, which is the maximum tolerated dose. Regardless of secondary disorders, all patients scheduled for skin and lymph node operations under local anesthesia underwent surgery using this kind of anesthesia, including those for the nose and ear region. No suprarenin was added for nerve blocks of the fingers and penis. This technique was used in 20,310 major and minor skin operations in 11,810 patients ranging in age from 0.5 years (510 children under 14 years) to 95 years (mean age 55 years; 49% females, 51% males), including all types of local flaps and grafts. There were no complications whatsoever from local anesthesia. The technique proved safe and comfortable even for children and very sensitive patients. The median duration of postoperative anesthesia was 4.3 h (maximum 23 h). We found that experience is required for correct selection of the needle position, the flow rate, and the volume.     

Thyroid and parathyroid surgery performed with patient under regional anesthesia

Thyroid and parathyroid surgery is usually performed with the patient under general anesthesia; however, for selected patients regional anesthesia may be preferable. Between September 1977 and March 1986 regional anesthesia was used successfully as the sole anesthetic technique in 17 patients who underwent thyroid surgery and two patients who underwent parathyroid surgery. Procedures included two total thyroidectomies, 14 lobectomies or lobectomies with isthmusectomies, and one isthmusectomy. These 17 operations represent approximately 5% of the thyroid operations performed by the senior surgeon over the corresponding time. One patient underwent combined completion thyroidectomy and parathyroidectomy, and another patient underwent successful parathyroidectomy under regional anesthesia. In two additional patients, procedures could not be completed under regional anesthesia alone. In one of these two patients regional anesthesia appeared to effect a transient recurrent nerve paralysis. The indications for use of regional anesthesia have been primarily patient preference and associated cardiac or pulmonary disease. We now consider as contraindications to regional anesthesia patient apprehension about the technique, deafness, high spinal cord injury, recurrent laryngeal or phrenic nerve palsy, and allergy to local anesthesia. During this period, from 1977 to 1986, our administration of regional anesthesia has evolved from bilateral deep and superficial cervical plexus blocks to bilateral superficial blocks alone using bupivacaine with epinephrine, 1:200,000.     

The impact of acoustic stimulation on the AEP monitor/2 derived composite auditory evoked potential index under awake and anesthetized conditions

The AEP Monitor/2 features an auditory evoked potential (AEP) and electroencephalogram (EEG)-derived hybrid index of the patient's hypnotic state. The composite AEP index (AAI) is preferably calculated from the AEP, but in case of low signal quality it is based entirely on the spontaneous EEG. We investigated the impact of auditory input on the AAI in 16 patients with correctly positioned headphones for acoustic stimulation and headphones disconnected from the patient's ears under awake and anesthetized conditions. The AAI and the Narcotrend Index (NI), another EEG-based measure of hypnotic depth, were recorded simultaneously. AAI values under awake and anesthetized conditions were higher with correctly positioned headphones than with headphones disconnected from the patient's ears (P < 0.05) but remained within the range indicating the patient's actual hypnotic state as given by the manufacturer of the monitor. Under awake conditions with correctly positioned headphones we observed frequent fluctuations between AEP-derived and EEG-derived AAI, whereas with headphones disconnected from the patient's ears the AAI calculation was completely EEG based. Acoustic stimulation had no impact on the Narcotrend Index. Although relevant misinterpretations of the patient's hypnotic state as a consequence of a turnover from AEP-derived to EEG-derived AAI values should not occur, an improved harmonization of the two methods of indexing would be desirable. IMPLICATIONS: The AEP Monitor/2 generates an Index (AAITM) indicating the patient's hypnotic state by analyzing either auditory evoked potentials (AEP) or spontaneous electroencephalographic (EEG) activity. We demonstrate that, though significantly different under AEP-derived or EEG-derived conditions, AAI values remain within the range indicating the patient's actual hypnotic state as given by the manufacturer of the device.     

Hydrodistension under local anesthesia for patients with suspected painful bladder syndrome/interstitial cystitis: Safety,diagnostic potential and therapeutic efficacy

Objectives: To evaluate the safety, diagnostic potential and therapeutic efficacy of cystoscopy with hydrodistension under local anesthesia in patients with suspected painful bladder syndrome/interstitial cystitis (PBS/IC). Methods: Thirty‐six patients with frequency, urgency or bladder pain for ≥6 months and an average voided volume of <200 mL were enrolled in the study. Hydrodistension was carried out 10 min after instillation of 10 mL of 4% lidocaine. The instilled saline volume for hydrodistension was determined based on each patient's level of tolerance of urinary sensation and symptoms. Results: Overall, 30 patients (median age 54 years, range 25–76) were evaluated. The median instilled saline volume was 450 mL (250 to 580 mL). No patients were admitted to hospital due to adverse events associated with hydrodistension. Glomerulation was found in 23 patients and two had Hunner's ulcers. Therapeutic efficacy at one month after hydrodistension was shown in 21/30 patients (71%). A median efficacy period of 20 ± 3.7 weeks was determined by Kaplan–Meier analysis. Factors with an independent influence on therapeutic efficacy of hydrodistension were not identified, but patients with an instilled volume greater than the median volume had significantly longer efficacy periods (P < 0.022). Conclusions: Cystoscopy with hydrodistension under local anesthesia provides a simple and safe method for differential diagnosis and has some therapeutic efficacy in patients with suspected PBS/IC.