Cord Position Research Articles

Use of neuromuscular blockade with rocuronium bromide for intubation in cats

ObjectiveTo determine whether neuromuscular blockade with rocuronium bromide (RB) would improve endotracheal intubation (EI) conditions in comparison with topical lidocaine hydrochloride (LH). Study designRandomized prospective study. AnimalsForty seven healthy cats of unspecified breed, aged 17 ± 11 months and weighing 2.8 ± 0.8 kg, undergoing elective procedures. MethodsAnesthesia was induced with xylazine (XZ) (1.1 mg kg−1 IM) and tiletamine‐zolazepam (XTZ) (7 mg kg−1 IM) and EI was attempted. Cats which could not be intubated at the first attempt (n = 34), were randomly medicated with either 0.1 mL LH 10% spray on the laryngeal mucosa (n = 17) or 0.6 mg kg−1 intravenous RB (n = 17). Sixty seconds later, a second attempt at EI was performed. The effect of both drugs was assessed using a previously published scale (Sandor Agoston). EI conditions associated with laryngoscopy, vocal cord position and movement, cough, patient movement, time and attempts needed in order to perform EI were recorded. Heart rate and end‐expired CO2 concentration were monitored. ResultsGroups were comparable in age, weight, gender and hematological parameters. Clinically acceptable EI conditions were not significantly different between RB and LH assisted groups (p = 0.31). However, there was a significant difference in cough, vocal cord movement and position between the RB and the LH groups. The group intubated at the first attempt and receiving neither RB nor LH coughed persistently (11/13). The cats receiving RB had to be ventilated for 10–28 minutes. Conclusions and clinical relevanceThe present study shows that, when used in cats anesthetized with XTZ, RB paralyzes the internal laryngeal muscles keeping the vocal cords in an intermediate position (paramedial) 60 seconds after being administered. RB is an effective alternative to LH to overcome the airway protective reflexes when performing EI but requires ventilatory support until the paralysis wears off.

Cricothyroid muscle dysfunction impairs vocal fold vibration in unilateral vocal fold paralysis

The relevance of the cricothyroid (CT) muscle in patients with unilateral vocal fold paralysis (UVFP) remains controversial. To clarify the functional significance of the CT muscle in patients with UVFP, the confounding effect of the severity of recurrent laryngeal nerve injury should be taken into consideration. In the present study, quantitative laryngeal electromyography (LEMG) was used to measure the severity of paralysis of the thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex to allow the functional contribution of the CT muscle to be determined. Cross-sectional study performed in an otolaryngology outpatient clinic. Thirty-one patients with a main diagnosis of UVFP were recruited. The main outcome measures included LEMG examination, quantitative LEMG analysis of the TA-LCA muscle complex, UVFP-related quality-of-life questionnaire (Voice Outcome Survey [VOS]), voice acoustics analysis, videolaryngostroboscopy, and general quality-of-life questionnaire (Short Form-36 Health Survey [SF-36]) assessments. The vocal cord position did not differ between patients with and without CT muscle impairment. Patients with both TA-LCA and CT paralysis showed poorer vocal fold vibration (P = .048) and higher fundamental frequency (P = .02), and the VOS and SF-36 were both poorer compared with patients with only TA-LCA paralysis. Although the vocal cord position was not influenced by CT muscle function, coexisting CT muscle paralysis may damage the voice by impairing vocal fold vibration in UVFP patients.

Activities of daily living and lesion position among multiple sclerosis patients by Bayes network.

Magnetic resonance imaging is a highly sensitive approach for diagnosis of multiple sclerosis, and T2-weighted images can reveal lesions in the cerebral white matter, gray matter, and spinal cord. However, the lesions have a poor correlation with measurable clinical disability. In this study, we performed a large-scale epidemiological survey of 238 patients with multiple sclerosis in eleven districts by network member hospitals in Shanghai, China within 1 year. The involved patients were scanned for position and size of lesions by MRI. Results showed that lesions in the cerebrum, spinal cord, or supratentorial position had an impact on the activities of daily living in multiple sclerosis patients, as assessed by the Bayes network. On the other hand, brainstem lesions were very unlikely to influence the activities of daily living, and were not associated with the position of lesion, patient's gender, and patient's living place.

Impact of the spinal cord position uncertainty on the dose received during head and neck helical tomotherapy

The study aims to establish the optimal planning risk volume (PRV) to the spinal cord (SC) for oropharyngeal cancer patients during adaptive radiation therapy with concurrent chemotherapy. Geometrical uncertainties of the SC were evaluated. Differences between planned and delivered maximum doses to each part of the SC were established for every fraction dose and for cumulative dose. Maximum doses were evaluated as a dose received in 0.5 and 1 cm(3) of the analysed part of the SC defined as C1-C2, C3-C4, C5-C6 and C7-Th1 where Cn was a n-th cervical vertebra (n = 1, … , 7) and Th1 was the first thoracic vertebra. Finally, relations between dose differences and geometrical uncertainties were analysed using a relative risk (RR) and the importance of the PRV dose gradient to establish an optimal PRV for the SC. Prospective study based on the 875 observations from 25 oropharyngeal cancer patients was performed. The C1-C2 part of the SC is most exposed to risk of overdosage during chemoradiation for patients with oropharyngeal cancer due to its proximity to the clinical target volume (CTV). Doses received by other parts of the SC are smaller, with the lowest dose delivered to C7-Th1. For the C1-C2, delivered dose was higher than planned dose by 11%, while for the C7-Th1, this difference was smaller than 7%. The lowest movement of individual parts of the SC were detected for the C1-C2 and the highest for the C7-Th1. The standard deviations of the mean shift ranged respectively from 0.9 to 1.4 mm and from 1.3 to 2.9 mm. For each part of the SC delivered dose was smaller than planned dose to the PRV (RR < 1). Our study showed that for chemoradiation of oropharyngeal cancer, using daily image guidance and proper plan adaptation scheme, the current PRV margin for the SC could be reduced to 4 mm.

EP-1258: Impact of the spinal cord position uncertainty on the dose received

EP-1258: Impact of the spinal cord position uncertainty on the dose received

Similar-Case-Based Optimization of Beam Arrangements in Stereotactic Body Radiotherapy for Assisting Treatment Planners

Objective. To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT) to assist treatment planners. Methods. First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV) location, PTV shape, lung size, and spinal cord position. Second, initial beam arrangements were determined by registration of similar cases with the objective case using a linear registration technique. Finally, beam directions of the objective case were locally optimized based on the cost function, which takes into account the radiation absorption in normal tissues and organs at risk. The proposed method was evaluated with 10 test cases and a treatment planning database including 81 cases, by using 11 planning evaluation indices such as tumor control probability and normal tissue complication probability (NTCP). Results. The procedure for the local optimization of beam arrangements improved the quality of treatment plans with significant differences (P < 0.05) in the homogeneity index and conformity index for the PTV, V10, V20, mean dose, and NTCP for the lung. Conclusion. The proposed method could be usable as a computer-aided treatment planning tool for the determination of beam arrangements in SBRT.

Magnesium sulphate

Tracheal intubation without administration of a neuromuscular blocking drug is used frequently in anaesthesia. Several techniques and adjuvants have been tried to improve intubating conditions. Magnesium sulphate is an agent with analgesic, anaesthetic and muscle relaxant effects. To assess the effect of magnesium sulphate on intubating conditions after induction of anaesthesia without a neuromuscular blocking drug. Double-blinded randomised study. Sixty patients with American Society of Anesthesiologists physical status 1/2 scheduled for elective surgery under general anaesthesia were included. Avicenna Military Hospital between June 2010 and March 2011. Before induction of general anaesthesia, patients were assigned to receive either a 10-min infusion of magnesium sulphate 45 mg kg(-1) in 100 ml of isotonic saline (magnesium group, n = 30) or the same volume of saline (control group, n = 30). Anaesthesia was induced with fentanyl 3 μg kg(-1) followed 3 min later by propofol 2.5 mg kg(-1). Intubating conditions were evaluated by a blinded anaesthesiologist using the criteria of the Copenhagen consensus conference: ease of laryngoscopy, vocal cord position and/or movement and response to intubation or cuff inflation (cough or diaphragmatic movement). Intubating conditions were considered as acceptable (excellent or good) or unacceptable (poor). Mean arterial pressure and heart rate were also recorded during the study period. The two groups were comparable in their demographic profiles. Clinically acceptable intubating conditions were observed more frequently in the magnesium group than in the control group: 25 (83%) vs. 18 patients (60%) (P = 0.042). There was no failed intubation. There were no differences between the groups with regard to haemodynamic variables. Addition of magnesium sulphate to propofol and fentanyl at induction of anaesthesia significantly improved intubating conditions without administration of a neuromuscular blocking drug.

Tracheal Intubation Without the Use of Neuromuscular Blocking Agents

Dear Editor, I read with keen interest the article by Imani et al. (1) in which the authors compare tracheal intubating conditions following intravenous (IV) administration of remifentanil 5 μg/kg or alfentanil 50 μg/kg followed by induction of anesthesia with propofol 2 mg/kg in 100 adult patients premedicated with IV midazolam 1 mg. Intubating conditions were assessed (scoring 1 to 4) by ease of laryngoscopy, patency of vocal cords, jaw relaxation, and limb movement. Airway reaction to tracheal intubation is an important consideration while assessing intubating conditions. Viby-Mogensen et al. (2) describe a qualitative scoring system graded as excellent, good or poor, respectively, comprising of five variables: Laryngoscopy (easy, fair, difficult) Vocal cord position (abducted, intermediate, closed) Vocal cord movement (none, moving, closing) Coughing (none, diaphragmatic, sustained, > 20 s) Movement of the limbs (none, slight, vigorous) Intubating conditions are regarded as excellent (all qualities are excellent), good (all qualities are either excellent or good), and poor (the presence of a single quality listed under poor) (2). They further regard excellent or good intubating conditions as clinically acceptable; and poor intubating conditions as clinically not acceptable. It would be interesting to compare the two narcotic regimens (remifentanil vs. alfentanil) for tracheal intubation without neuromuscular blocking agents (NMBAs) with regard to the incidence of coughing. Tracheal intubation is associated with hemodynamic changes. In this regard, the use of remifentanil 5 μg/kg would be expected to cause significant hypotension and/or bradycardia. It would be useful to know the incidence of hypotension or bradycardia and also if there was need for administration of vasopressors or atropine. I am intrigued by two statements in the article that are in contradistinction: The combination of remifentanil with propofol may also be advantageous in cases of long and difficult intubation, wherein it may not only be possible to inspect the airway with the laryngoscope. Thus, this method is best avoided in patients with high Mallampati grades or airway difficulties. The technique of tracheal intubation without the use of NMBAs enables us to assess the airway by laryngoscopy. This technique may be useful in cases of both predicted and unexpected difficult intubation, in cases where NMBAs are either contraindicated (e.g. myopathies) or not required to facilitate surgical access (3).

Comparison of intubating conditions following administration of low-dose rocuronium or succinylcholine in adults: A randomized double blind study.

Context:Though rocuronium has a rapid onset of neuromuscular blockade like succinylcholine without the latter's adverse effects, its use is limited due to its prolonged action.Aim:Aim was to evaluate whether reducing the intubating dose of rocuronium shortens its duration of action, yet provides clinically acceptable intubating conditions.Settings and Design:tt was a prospective, randomized, and double blind trial.Materials and Methods:100 American Society of Anaesthesiologists Physical Status (ASAPS) I or II patients aged between 18–65 years scheduled for elective surgery were randomly allotted one of the four rocuronium groups (rocuronium dose of 0.3 mg/kg intubated at 60 s or at 90 s, rocuronium 0.6 mg/kg intubated at 60 s or at 90 s) orsuccinylcholine group (succinylcholine 1.0 mg/kg intubated at 60 s) and intubating conditions were assessed with: Ease of laryngoscopy, vocal cord position, and reaction to insertion of tracheal tube and cuff inflation.Statistical Analysis:Statistical tests used were analysis of variance (ANOVA), Chi-Square test, Repeated measures of ANOVA and Mann–Whitney U test.Results:Rocuronium in dosage of 0.3 mg/kg gaveclinically acceptable intubating conditions in 35% and 60% subjects at 60 s or 90 s, respectively, whereas in dosage of 0.6 mg/kg, intubating conditions were acceptable in 80% and 100% subjects intubated at 60 s and 90 s.Conclusion:Rocuronium in dose of 0.3 mg/kg does not give clinically acceptable intubating conditions at 60 or 90 s but has shorter duration of action. Rocuronium in dose of 0.6 mg/kg gives clinically acceptable intubating conditions at 60 or 90 s, comparable to succinylcholine 1 mg/kg.

Improving Patient Experience with Spinal Cord Stimulation: Implications of Position-Related Changes in Neurostimulation

The objective of this narrative review is to discuss the clinical implications of position-related changes in spinal cord stimulation and technological improvements to better meet patient needs. Keywords applicable to spinal cord stimulation therapy, including paresthesia perception, spinal cord position, lead impedance, and sensor technologies, were searched in the PubMed, EMBASE, and Cochrane Library databases. Literature analysis, combined with extensive clinical experience with spinal cord stimulation therapy, forms the basis of this review. Fluctuations in paresthesia perception are largely caused by variation in the distance between the fixed electrodes and the spinal cord consequent to patient movement. Patients employ multiple strategies with varying success to manage position-related fluctuations in stimulation perception, which may result in suboptimum therapy delivery. A new type of spinal cord stimulation system that incorporates accelerometer technology to automatically adjust stimulation amplitude based on patient position may better meet patient analgesic needs and is in early clinical application.

In Response

We welcome the debate offered by Machi et al.1 regarding the validity of our study findings.2 Unfortunately, the authors have misunderstood key parts of the article. The article's brief report format did not enable us to describe the anesthetic methodology not pertinent to the study's primary outcome: 20-minute aggregate block score. Specifically, because lidocaine was used for the infraclavicular block, elective ropivacaine distal block supplementation was primarily for postoperative analgesia3 and not block failure. Thus, the surgical anesthesia success rate (defined as no intraoperative pain requiring infiltration or sedation) was not 49% vs 55%, but was 96% vs 86%. Regardless, we urge extreme caution comparing study success rates, as apparent differences can be due to the block testing method (pinprick2,3 vs cold stimulus4), the timing of testing (as early as 15 minutes3 or as late as 45 minutes), use of elective supplementation, and the definition of surgical anesthesia success (level of analgesia/sedation permitted). Our study used stringent criteria during early block progression: complete loss of pinprick sensation and all movement at 20 minutes, and a similarly stringent definition for surgical anesthesia success. Machi et al. challenge the frequency with which we were able to visualize all 3 cords, because it was less than the authors' experience of 99%. Consequently, they question the triple-injection arm, which allowed arbitrary local anesthetic placement at 2, 6, and 8 o'clock when cord visualization was not possible. In fact, this triple-injection method was based on Sandhu and Capan's5 influential observational study which reported that the cords were “easily imaged in all patients” (n = 126) at approximately 2, 6, and 8 o'clock, and the work of Perlas et al.,6 another experienced ultrasonographer who, using a cart-based machine, reported cord visualization in only 27% of patients. Furthermore, this triple-injection technique was almost identical to that used in another similar randomized trial.4 We agree that the single-injection technique is not a true “single” injection, because some needle manipulation was permitted posterior to the artery in a cephalocaudad direction “not extending beyond the cepahalocaudad borders of the artery.” However, nowhere is it stated that the “single-injection technique was manipulated to involve up to 50% circumference of the artery”; rather, “some needle manipulation was permitted to promote a shallow saucer-shaped spread dorsal to the artery.” Regardless, we fail to appreciate how this minor needle manipulation would invalidate our findings. Finally, evidence-based medicine gives the highest weight to evidence supported by more than 1 large blinded randomized controlled trial. Although small (n < 30) observational studies have suggested significant cord position variability, and the presence of septa—which might provide an anatomical rationale for multiple injections—2 large (n = 100) randomized trials instead, now support the use of a single injection posterior to the axillary artery.2,4 Michael J. Fredrickson, FANZCA Philip Wolstencroft, FANZCA Departments of Anaesthesiology University of Auckland Auckland, New Zealand Department of Anaesthesia Auckland City Hospital Auckland, New Zealand [email protected]

Induction of tracheal intubation without muscle relaxant by target controlled infusion of propofol combined with remifentanil in children

To observe the safety and feasibility of tracheal intubation by target-controlled infusion of propofol and remifentanil without muscle relaxant in children. Totally 100 4-10-year-old pediatric patients (ASA1) who had been scheduled for plastic surgery were equally divided into remifentanil group and control group through computer-generated randomized grouping. In all patients, five minutes after intravenous administration of atropine 0.01 mg/kg and midazolam 0.1 mg/kg, propofol was infused at the targeted effect-site concentration (Ce of 6 μg/ml. When the intended target Ce of propofol was reached, the remifentanil group began to be infused with remifentanil at a Ce of 5 ng/ml, and normal saline (0.1 ml/kg) was injected simultaneously. In the control group remifentanil was replaced by normal saline and rocuronium (0.8 mg/kg) was injected together with the normal saline. After the equilibration of plasma and the Ce of remifentanil were reached, tracheal intubation was attempted. The complications during the induction and tracheal intubation were recorded. The intubating conditions were assessed using a five-point scoring system based on ease of laryngoscopy, vocal cords position, coughing, jaw relaxation and limb movement. The success rate of tracheal intubation was in 90% in remifentanil group and 98% in the control group (P=0.122).CONCLUSION Target-controlled infusion of propofol and remifentanil at Ce of 6 μg/ml and 5 ng/ml is feasible for the induction and tracheal intubation without muscle relaxant in children.

Cricothyroid approximation for voice and swallowing rehabilitation of high vagal paralysis secondary to skull base neoplasms

This study documents the speech and swallowing outcomes of isolated ipsilateral cricothyroid approximation (aka tensioning thyroplasty; Type IV thyroplasty) for the treatment of high vagal paralysis (combined superior laryngeal nerve and recurrent laryngeal nerve paralysis). This is a pilot study of five cases with high vagal paralysis consequent to skull base neoplasms. Unilateral cricothyroid tensioning sutures were used. In all cases, vocal fold tensioning and vertical realignment of lax vocal folds were achieved. A partial, but acceptable medialization of vocal cord position was achieved. In all cases, aspiration was minimized and normal swallow function was restored by 6 weeks. The voice outcome was excellent in four cases and acceptable in one. Cricothyroid approximation restores vocal fold tension; in addition, it restores vertical vocal fold position and partially restores horizontal vocal fold position. Good voice and swallowing outcomes have been achieved. The procedure is quick, safe, and convenient when combined with a skull-base excision procedure. Further evaluation is merited.

Propofol 2 mg/kg is superior to propofol 1 mg/kg for tracheal intubation in children during sevoflurane induction

Propofol has been used to facilitate tracheal intubation within a short time of sevoflurane induction without a muscle relaxant in children. We compared as the primary outcome the incidence of excellent intubating conditions after 8% sevoflurane and propofol 1 or 2 mg/kg. One hundred and four patients (2-7 years) were randomly assigned to receive propofol 1 mg/kg in group SP1 (n=53) or propofol 2 mg/kg in group SP2 (n=51) after inhalation induction using sevoflurane 8% in oxygen. Forty-five seconds after propofol and controlled ventilation, intubating conditions were assessed using a four-point scoring system based on ease of laryngoscopy, vocal cords position, coughing, jaw relaxation and limb movement. Heart rate and systolic blood pressure were measured as baseline, after sevoflurane induction, propofol, intubation and at 2 and 5 min following intubation. Three patients in group SP1 were excluded from analysis. Time from sevoflurane induction to intubation (248.9±71.3 s in group SP1 vs. 230.9±61.3 s in group SP2) and endtidal sevoflurane before intubation (5.6±1.6% in group SP1 vs. 5.2±1.5% in group SP2) did not differ between the two groups. The incidence of excellent intubating conditions was significantly higher in group SP2 compared with group SP1 [47/51 (92%) vs. 28/50 (56%)]. The incidence of acceptable intubating conditions was significantly higher in group SP2 compared with group SP1 [48/51 (94%) vs. 35/50 (70%)]. No hemodynamic difference was noted at any time point between the two groups. Propofol 2 mg/kg during 8% sevoflurane induction resulted in a higher proportion of excellent intubating conditions compared with propofol 1 mg/kg.

Early versus late injection medialization for unilateral vocal cord paralysis

To evaluate whether the timing of early (≤6 months from time of nerve injury) vs. late (>6 months) injection medialization laryngoplasty impacts the need for subsequent open-neck reconstruction to restore vocal function in patients with unilateral vocal cord paralysis. Retrospective chart review. A total of 112 outpatient or hospitalized adults with dysphonia resulting from postsurgical or idiopathic unilateral vocal cord paralysis were identified who were injected as initial treatment within 1 year of onset of their paralysis. All subjects underwent awake, transoral, paraglottic injection with absorbable hyaluronic-acid gel. Patients with documented recovery of vocal cord mobility (22), active disease directly affecting the recurrent laryngeal nerve (8), <3 months of follow-up after injection (time for gel to be reabsorbed) (34), or deaths within 1 year after the onset of paralysis (13) were excluded, leaving a study population of 35 patients. Twenty of 32 (62.5%) patients with early injection medialization maintained an adequate voice, obviating the need for open-neck phonosurgical reconstruction; their follow-up from onset of paralysis ranged from 4.0 to 41.8 months (mean 15.2). None of the three patients undergoing late injection (>6 months postparalysis) avoided phonosurgical reconstruction (P = .03, χ2 test). Patients receiving early injection medialization for vocal cord paralysis were less likely to require transcervical reconstruction. We believe that early medialization creates a more favorable vocal cord position for phonation that can be maintained by synkinetic reinnervation, in contrast to the final position of a lateralized vocal cord being determined solely by reinnervation.

What is the optimal remifentanil dosage for providing excellent intubating conditions when coadministered with thiopental? A prospective randomized dose–response study

The aim of the present study was to determine the dosage of remifentanil that must be added to thiopental 5 mg kg(-1) to provide excellent intubating conditions in 95% of patients. Sixty-eight premedicated female American Society of Anesthesiologists class 1 and 2 patients were randomly allocated to four remifentanil dose groups (3, 4, 5 or 6 microg kg(-1)). Induction of anaesthesia was performed with a blinded dose of remifentanil infused over 60 s, simultaneously coadministered with thiopental 5 mg kg(-1) infused over 20 s; and tracheal intubation was attempted 150 s after the beginning of induction. The intubating conditions were assessed with the Copenhagen score, according to jaw relaxation, resistance to laryngoscope, vocal cord position and movements and reaction to cuff inflation. A probit analysis was performed to calculate the intubating efficient doses (IEDs) of remifentanil in 50 and 95% of patients (IED50 and IED95). Haemodynamic tolerance was also analysed. The IED95 of remifentanil was 7.8 microg kg(-1) (95% confidence interval 5.9-10.9). Although the maximum decrease in heart rate and mean arterial pressure was less than 30% during induction of anaesthesia, the haemodynamic tolerance of such a relaxant-free protocol for anaesthesia providing excellent intubating conditions in 95% of patients when using remifentanil and thiopental could not be assessed, as the IED95 of remifentanil was more than 6 microg kg(-1). The dosage of remifentanil providing excellent intubating conditions in 95% of patients when coadministered with thiopental 5 mg kg(-1) in healthy premedicated female patients undergoing elective surgery was more than 7 microg kg(-1). Our results question the feasibility of using thiopental for a relaxant-free protocol for anaesthesia.

The effects of sevoflurane with propofol and remifentanil on tracheal intubation conditions without neuromuscular blocking agents

BackgroundPropofol and remifentanil are used for tracheal intubation in the absence of neuromuscular blocking agents. We hypothesized that the addition of sevoflurane to propofol and remifentanil would improve intubation conditions and provide hemodynamic stability.MethodsSeventy-six patients scheduled for elective surgery were randomly allocated to be ventilated with either 4% (group I) or 7% sevoflurane (group II) after propofol injection (2 mg/kg). All patients received remifentanil (1 µg/kg) 30 seconds after administration of propofol. Ninety seconds after remifentanil was given, laryngoscopy and tracheal intubation were performed. Intubation conditions and hemodynamic changes were evaluated.ResultsThe overall incidence of clinically acceptable intubation conditions was significantly higher in group II (92%) than group I (58%) (P = 0.001). Scores for vocal cord position, coughing, and limb movement were significantly better in group II (P < 0.05). Mean blood pressure remained significantly lower than the pre-induction level throughout the investigation in both groups (P < 0.001), but there was no incidence of bradycardia or hypotension requiring treatment.ConclusionsTracheal intubation without neuromuscular blocking agents can be achieved safely and reliably by adding 7% sevoflurane to propofol (2 mg/kg) and remifentanil (1 µg/kg).

Effects of Ephedrine on Intubating Conditions Following Priming with Atracurium: A Randomized Clinical Trial

Priming is a well-known method to accelerate the onset of action of nondepolarizing neuromuscular-blocking agents. It consists of administration of a small dose of neuromuscular blocking agent several minutes before the principal dose is given. Ephedrine has been shown to improve the intubating conditions of rocuronium following its priming with a small dose. However, the potential effects of ephedrine on intubating conditions using atracurium after its priming with a small dose have not yet been studied. Since rocuronium is not available in Iran, atracurium is widely used as an alternative. We studied two groups of patients, each group consisting of 32 patients. One group received ephedrine after priming (PE) and the other received placebo following priming (P). There were no significant differences between the two groups in age, sex, physical status (assessed using the American Society of Anesthesiologists classification), baseline mean arterial pressure and baseline heart rate. Patients with anticipated difficult airway, hypertension, obesity, any evidence of neuromuscular, cardiovascular, respiratory, hepatic, or renal disease, as well as those taking medications known to interact with atracurium or ephedrine were excluded. The anesthesiologist, the physician responsible for recording the results, and the statistician interpreting them were blinded to group allocations. Intubating conditions were graded according to Cooper's criteria. A clinically acceptable outcome was defined as good or excellent intubating conditions, represented by overall scores of 6-7 and 8-9, respectively. Intubating conditions were clinically acceptable in 22 patients in the PE group and 15 patients in the P group (p = 0.13). Vocal cord position and jaw relaxation scores during intubation and response to intubation did not differ significantly between the two groups. The mean arterial pressure showed significant differences over the course of time between the two groups (p < 0.01). Heart rate exceeded 120 bpm more frequently in the PE than in the P group (p < 0.01). The effects of ephedrine on improving intubating conditions following atracurium priming were not statistically significant. Given the risk of exacerbation of coronary ischemia by tachycardia, and the negative results on intubating conditions in our study, we cannot recommend the use of ephedrine for improving intubating conditions following priming with atracurium.

94. A Comparison Study of the Surgery for OPLL of Cervical Spine Between Anterior Floating Method and Laminoplasty

BACKGROUND CONTEXT: The OPLL of cervical spine is the major disease in Japan, so the several surgical procedures was developed in Japan. The procedures were divided into anterior decompression and fusion, and posterior decompression. Laminoplasty is gold standard procedure for OPLL because of the less invasiveness and stable clinical results. But the anterior procedure is an ideal procedure for the spinal cord position. It is difficult to find a comparison study of anterior procedure and posterior procedure.

OC138: Suggested pathophysiology for the high incidence of cord entanglement during early pregnancy detected by three‐dimensional sonography

Objectives: 1) To determine the incidence of cord entanglement during early gestation using three dimensional (3D US) sonography. 2) To establish relationship between fetal and umbilical cord lengths, as a suggested pathophysiology for the cord entanglement incidence throughout pregnancy. Material and Methods: A prospective consecutive study was designed and 3D US was performed. Two hundred and thirty seven singleton pregnancies between 13–16 weeks were included. Cord entanglement was defined when one or more of the following was detected: cord around neck, hand, leg, thorax, abdomen shoulder, pelvis. Floating free cord through all its length in the amniotic fluid was defined as normal position cord. Results: Abnormal cord position was observed in 149 (62.9%) patients. Of those: 42.9.0% around neck, 15.4% legs, 12.7% hands, 4.8% -abdomen, 24.2% -other body parts (thorax, shoulder and pelvis). Incidence of total cord entanglement was similar between 13–16 weeks gestation. A decreasing ratio between cord length and CRL (according to literature) was calculated throughout pregnancy. Conclusions: A high incidence of early second trimester cord entanglement was found. This may be explained by the high calculated ratio between cord and fetal lengths during early pregnancy. Cord entanglement should be considered a part of normal early fetal movements and development.