An Evaluation of the ACEP Guideline for Mild Head Injuries in Taiwan

Introduction

Traumatic brain injury (TBI) is an important issue in the emergency department. In the United States, the American College of Emergency Physicians (ACEP) published clinical guideline to select patients with mild head injuries for head computed tomography (CT) scans in 2008. The aim of this study was to identify the possible benefits of compliance with these guidelines for mild head injury patients in Taiwan.

Method

This was a secondary analysis on our previous study published for association of hypertension and head injuries. In our previous study, we collected data about 1290 patients with head injuries who received brain CT scans in the emergency department from September 2012 to August 2013 for a study regarding the association between head injury and hypertension. In present study, we subjected this data to further analysis to try to validate the ACEP clinical policy for mild head injuries.

Results

Of these 1,290 patients, 154 were found to have brain haemorrhage on the initial brain CT scan, and 5 were in need of neurosurgical intervention. A total of 859 patients met the ACEP guideline criteria, and 117 of these had brain haemorrhages. The sensitivity and specificity of the ACEP guideline to predict brain haemorrhage were 75.97% (95% confidence interval [CI], 68.44% to 82.48%) and 34.68% (95% CI, 31.91% to 37.53%), respectively. In predicting neurosurgical intervention, the sensitivity and specificity of the guideline were 100% (95% CI, 47.82% to 100%) and 33.54% (95% CI, 30.96% to 36.2%), respectively.

Conclusion

Although adoption of the ACEP clinical policy may reduce the number of brain CT scans in mild head injury patients who may need neurosurgical interventions, it is not a good selection tool in Taiwan.

Limits of Calcaneal Lengthening for Treating Planovalgus Foot Deformity in Children With Cerebral Palsy

BACKGROUND

Calcaneal lengthening is used to correct symptomatic planovalgus foot deformity, but outcomes have been less satisfactory in children with cerebral palsy. This study aimed to define limits of calcaneal lengthening by analyzing the risk factors for undercorrection of deformity.

METHODS

We retrospectively reviewed 20 cases of children with cerebral palsy who underwent calcaneal lengthening of 30 planovalgus feet at a mean age of 11.9 years. Foot deformities were evaluated by the anteroposterior talo-first metatarsal angle (normal, 10 ± 7.0 degrees), lateral talo-first metatarsal angle (normal, 13 ± 7.5 degrees), and lateral calcaneal pitch angle (normal, 17 ± 6.0 degrees) on standing foot radiographs. Among these parameters, a corrected foot was defined as 2 or 3 parameters being corrected to within a normal range, and an undercorrected foot was only 1 or no parameter being corrected to within a normal range. Factors were compared between the corrected group and undercorrected group for significant predictors, and cutoff values of predictors were calculated for use as a clinical guideline.

RESULTS

Seventeen planovalgus feet were corrected satisfactorily by calcaneal lengthening, while the other 13 feet were undercorrected. Undercorrected feet had a greater preoperative anteroposterior talonavicular angle (33.7 vs 22.8 degrees, P = .001) and a smaller lateral calcaneal pitch (-1.7 vs 5.6 degrees, P = .03). A talonavicular angle of more than 24 degrees and calcaneal pitch less than -5 degrees were identified as cutoff values using a receiver operating characteristic curve. The predicted probability of undercorrection was 100% (9/9 feet) for 2 positive predictors, 50% (8/16 feet) for 1 positive predictor, and 0 (0/5 feet) for zero predictors.

CONCLUSION

A talonavicular lateral subluxation of more than 24 degrees on the anteroposterior radiograph and a calcaneal pitch angle less than -5 degrees on the lateral radiograph were 2 independent predictors that could be used to identify a planovalgus deformity that would be beyond the corrective capacity of calcaneal lengthening to restore normal alignment. Level of Evidence Retrospective case control study, level III.

Gross motor function change after multilevel soft tissue release in children with cerebral palsy

Background

Improving motor function is a major goal of therapy for children with cerebral palsy (CP). However, changes in motor function after orthopedic surgery for gait disorders are seldom discussed. This study aimed to evaluate the postoperative changes in gross motor function and to investigate the prognostic factors for such changes.

Methods

We prospectively studied 25 children with CP (4–12 years) who were gross motor function classification system (GMFCS) level II to IV and and underwent bilateral multilevel soft-tissue release for knee flexion gait. Patients were evaluated preoperatively and at 6 weeks and 3 and 6 months postoperatively for Gross Motor Function Measure (GMFM-66), range of motion, spasticity, and selective motor control. The associations between change in GMFM-66 score and possible factors were analyzed.

Results

25 children with gross motor function level II to IV underwent surgery at a mean age of 8.6 years (range, 4–12 years). Mean GMFM-66 score decreased from 55.9 at baseline to 54.3 at 6-weeks postoperatively and increased to 57.5 at 6-months postoperatively (p < 0.05). Regression analysis revealed better gross motor function level and greater surgical reduction of spasticity were predictors for decreased GMFM-66 score at 6-weeks postoperatively. Younger age was a predictor for increased GMFM-66 score at 6-months postoperatively.

Conclusion

Reduction of contracture and spasticity and improvement of selective motor control were noted after surgery in children with CP. However, a down-and-up course of GMFM-66 score was noted. It is emphasized that deterioration of motor function in children with ambulatory ability and the improvement in young children after orthopedic surgery for gait disorders.

Level of evidence

case series, therapeutic study, level 4.

Treatment of displaced flexion-type pediatric supracondylar humeral fractures in the prone position

PURPOSE

This study is to report a new method to reduce and fix the displaced flexion-type pediatric supracondylar fracture in the prone position.

METHODS

Ten children with displaced flexion-type supracondylar humeral fractures treated between 2007 and 2013 were reviewed. There were three girls and seven boys, with a mean age of 9.5 years. The fracture was reduced by gentle traction of the forearm and gradual extension of the elbow in the prone position. Two or three crossed Kirschner wires (K-wires) were inserted percutaneously to secure the fracture reduction. Radiographic evaluation included the Baumann's angle and the lateral humerocapitellar angle. Clinical outcomes were assessed using the Flynn's criteria.

RESULTS

Eight children had closed reduction and percutaneous K-wire fixation. The other two children required open reduction through a posterior triceps splitting approach. The mean Baumann's angle was 70.2° immediately after K-wires fixation and 69.5° after 3 months later. The mean lateral humerocapitellar angle was 38° immediately after K-wires fixation and 35.5° after 3 months later. The clinical outcome was excellent in nine children and poor in one child by the Flynn's criteria.

CONCLUSION

Reduction of displaced flexion-type pediatric supracondylar humeral fractures by traction and gradual extension in the prone position is an effective and safe method. When reduction is still impossible or nerve incarceration is suspected, open reduction and release of the trapped nerve through a posterior triceps splitting approach are simply accessible.

Clinical significance of anterior humeral line in supracondylar humeral fractures in children

INTRODUCTION

Anterior humeral line (AHL) location is commonly used to evaluate sagittal alignment after fracture reduction in children with supracondylar humeral fractures. However, the position of the AHL for acceptable fracture reduction has not been validated by clinical outcome. The purpose of this study was to investigate the relationship between the location of AHL and range of elbow motion.

PATIENTS AND METHODS

We retrospectively reviewed 101 children who underwent closed reduction and percutaneous pinning for Gartland type III supracondylar humeral fractures between January 2009 and June 2014. There were 67 boys and 34 girls, with a mean age of 7 years. The children were classified according to the location of the AHL three months postoperatively into five groups: anteriorly loss (n=6), anterior third (n=25), middle third (n=47), posterior third (n=21), and posteriorly loss (n=2). Range of elbow motion was measured by attending paediatric orthopaedic surgeons with a goniometer. Clinical and radiographic outcomes were compared among the five groups.

RESULTS

The mean elbow extension angle was not significantly different among the groups (p=0.21). However, children with AHL anterior to the capitellum had less elbow flexion angle (125.8° vs. 131.2°, p=0.046) and less total range of elbow motion (128.3° vs. 135.7°, p=0.048) than children with AHL crossing the capitellum. When the AHL crossed the capitellum, the elbow flexion angle and total range of elbow motion were significantly decreased in children with AHL crossing the anterior third of the capitellum. The Flynn criteria were not significantly different among the central three groups (p=0.131). However, the Flynn criteria were significantly worse in children whose AHL missed the capitellum (p<0.001). The mean Baumann angle measured 3 months postoperatively was not significantly different among the groups (p=0.12).

CONCLUSIONS

These findings demonstrate that children with AHL crossing the middle and posterior thirds of the capitellum appear to have slightly better early elbow flexion and total range of elbow motion. AHL crossing the anterior third of the capitellum can be an underreduction that has similar elbow motion as AHL anterior to the capitellum. AHL posterior to the capitellum is a warning sign of overreduction and should be avoided.

Immunological impression cytology of the conjunctival epithelium in patients with thyroid orbitopathy-related dry eye

Thyroid orbitopathy (TO) is an autoimmune disease that is complicated by ocular surface disorders, leading to discomfort. Dry eye is very prevalent in patients with TO. Recent studies on the pathogenesis of dry eye have focused on the inflammatory process, and some supporting evidence has been discovered. Because TO is a disorder of autoimmune origin, we assumed that the association between TO and dry eye is related to inflammation. Inflammation of the ocular surface in TO-related dry eye has not been well studied. In this study, we assessed cellular inflammation of the ocular surface and the cytokine profiles in patients with TO-related dry eye. Conjunctival impression cytology (CIC) was assessed with an immunofluorescent assay. TO-related dry eye was diagnosed by using the Schirmer test, tear break-up time, thyroid function, and clinical signs. CIC was combined with immunological staining of interleukin-1a (IL-1a), IL-1b, and IL- 6. The immunological impression cytology (IC) grade was compared to the clinical activity score of TO. All TO patients with dry eye were positive for IL-1a, IL-1b, and IL-6. However, the normal controls were also positive for IL-1a. A trend was observed between the clinical inflammatory score and immunological IC grade. This study was the first to delineate the immunological IC of TO-related dry eye. Our study aimed to investigate the pathogenesis of dry eye in TO. Our findings suggest that the conjunctival cytokines IL-1a, IL-1b, and IL-6 may play a role. The results of this study will be useful for future studies of additional inflammatory cytokines, and the levels of these cytokines could be used as an outcome to assess the efficacy of treatment, such as anti-cytokine or immunosuppression therapy, in patients with TO-related dry eye or other ocular surface inflammatory disorders.

Econazole induces increases in free intracellular Ca2+ concentrations in human osteosarcoma cells

Econazole is an antifungal drug with different in vitro effects. However, econazole's effect on osteoblast like cells is unknown. In human MG63 osteosarcoma cells, the effect of econazole on intracellular Ca2+ concentrations ([Ca2+]i) was explored by using fura-2. At a concentration of 0.1 μM, econazole started to cause a rise in [Ca2+]i in a concentration-dependent manner. Econazole-induced [Ca2+]i rise was reduced by 74% by removal of extracellular Ca2+. The econazole-induced Ca2+ influx was mediated via a nimodipine-sensitive pathway. In Ca2+ free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+ ATPase, caused a [Ca2+]i rise, after which the increasing effect of econazole on [Ca2+]i was abolished. Pretreatment of cells with econazole to deplete Ca2+ stores totally prevented thapsigargin from releasing Ca2+. U73122, an inhibitor of phospholipase C, abolished histamine (an inositol 1,4,5-trisphosphate dependent Ca2+ mobilizer)-induced, but not econazoleinduced, [Ca2+]i rise. Econazole inhibited 76% of thapsigargin-induced store-operated Ca2+ entry. These findings suggest that in MG63 osteosarcoma cells, econazole increases [Ca2+]i by stimulating Ca2+ influx and Ca2+ release from the endoplasmic reticulum via a phospholipase C-independent manner. In contrast, econazole acts as a potent blocker of store-operated Ca2+ entry.

Designing a stronger interface through graded structures in amorphous/nanocrystalline ZrCu/Cu multilayered films

Many multilayered nano-structures appear to fail due to brittle matter along the interfaces. In order to toughen them, in this study, the microstructure and interface strength of multilayered thin films consisting of amorphous ZrCu and nanocrystalline Cu (with sharp or graded interfaces) are examined and analyzed. The interface possesses a gradient nature in terms of composition, nanocrystalline phase size and volume fraction. The bending results extracted from the nano-scaled cantilever bending samples demonstrate that multilayered films with graded interfaces would have a much higher interface bending strength/strain/modulus, and an overall improvement upgrade of more than 50%. The simple graded interface design of multilayered thin films with improved mechanical properties can offer much more promising performance in structural and functional applications for MEMS or optical coating.

Influence of obesity on surgical outcomes in type III paediatric supracondylar humeral fractures

INTRODUCTION

Obesity was associated with poor treatment outcome in paediatric supracondylar humeral fractures. It is controversial about the association is related to more severe fractures in obese children or obesity directly affects treatment. The purpose of this study was to evaluate the influence of obesity on surgical outcomes after control of fracture severity.

PATIENTS AND METHODS

This is a retrospective comparative study of 107 children treated for type III supracondylar humeral fractures between January 2009 and December 2013. Children were classified according to sex-specific body mass index (BMI)-for-age growth chart into 4 groups: underweight group (n=10); normal-weight group (n=71); overweight group (n=13); and obese group (n=13). Clinical outcomes were assessed using the Flynn criteria. Radiographic evaluation included the Baumann angle and the lateral humerocapitellar angle. Loss of reduction was defined by Skaggs' criteria.

RESULTS

The mean age, sex, and Flynn criteria were comparable among the four BMI groups. Obese children were more likely to develop a varus change in the Baumann angle (p=0.017) and loss of reduction in varus (p=0.059) postoperatively. The risk for pin-related complications was significantly higher in overweight and obese children (p=0.013).

CONCLUSIONS

Obesity was associated with more postoperative varus deformation and pin-related complications after surgical fixation for type III supracondylar fracture. These findings underline the importance of stable fixation and close post-operative monitoring in obese children.

Effects of low amplitude pulsed radiofrequency stimulation with different waveform in rats for neuropathic pain

Pulsed-radiofrequency (PRF) electrical stimulation has been widely used for chronic pain treatment. It has been demonstrated with advantages of low temperature over traditional continuous radiofrequency (CRF) lesions with higher amplitude and mono polar electrode to treat pain in clinics (frequency 500 KHz, Pulse duration 20 msec, Amplitude 45 V, Treatment 2 min). We compare the effects of different pulse waveforms and PRF parameters (Pulse duration 25 ms, Treatment duration 5 min, low amplitude of 2.5/1.25 V) with a miniature bi-polar electrode on Dorsal root ganglion (DRG). The pain relief effect due to PRF is evaluated by using Von Frey method for the pain threshold index based on behavior response to mechanical stimulus of various strengths. Experimental results of Von Frey Score show that the sinusoidal group has higher responses than the square wave one. Both fast and secondary expressed proteins of c-fos and pp38 are measured from spinal cord tissue sectioning slides to characterize the pain associated inflammatory responses and their responses due to PRF stimulation.

Superradiant modes in resonant quasi-periodic double-period quantum wells

This paper firstly proposes the existence of superradiant modes in resonant quasi-periodic double-period quantum wells (QWs), which has not been observed from analyzing the structure factor by traditional methods. Using the gap map method, the reflection spectra under the relevant conditions show that there are dips in the middle and the linewidth grows linearly, despite the dips, as the number of QWs increases, which is a direct demonstration of superradiance. It is also found that the relevant conditions are divided into three regions, each of which has a different width of bandgaps.

Influence of lumbar curvature and rotation on forward flexibility in idiopathic scoliosis

BACKGROUND

Lumbar spine facet joints are arranged sagittally and mainly provide forward flexibility. Rotation of the lumbar vertebral body and coronal plane deformity may influence the function of lumbar forward flexibility. We hypothesize that the more advanced axial and coronal plane deformity could cause more limitation on forward flexibility in patients with idiopathic scoliosis.

METHODS

Between January 2011 and August 2011, 85 patients with adolescent idiopathic scoliosis were enrolled in this study. The proximal thoracic, major thoracic, thoracolumbar/lumbar (TL/L), and lumbar (L1/L5) curves were measured by Cobb's method. Lumbar apical rotation was graded using the Nash-Moe score. Lumbar forward flexibility was measured using the sit and reach (S and R) test. Statistical analysis was performed using one-way analysis of variance (ANOVA), Spearman's and Pearson's correlation coefficients.

RESULTS

The mean age was 16.1 ± 2.84 years. The mean proximal thoracic, major thoracic, TL/L, and L1/L5 curves were 17.61° ± 8.92, 25.56° ± 11.61, 26.09° ± 8.6, and 15.10° ± 7.85, respectively. The mean S and R measurement was 25.56 ± 12.33 cm. The magnitude of the TL/L and L1/L5 curves was statistically positively related to vertebral rotation (r(s) = 0.580 and 0.649, respectively). The correlation between the S and R test and both the TL/L and L1/L5 curves was negative (r(p) = -0.371 and -0.595, respectively). Besides, the S and R test also demonstrated a significant negative relationship with vertebral rotation (rs = -0.768).

CONCLUSION

In patients with idiopathic scoliosis, spinal deformity can diminish lumbar forward flexibility. Higher lumbar curvature and rotation lead to greater restriction of lumbar flexion.

Flatfoot diagnosis by a unique bimodal distribution of footprint index in children

BACKGROUND

More than 1000 scientific papers have been devoted to flatfoot issue. However, a bimodal distribution of flatfoot indices in school-aged children has never been discovered. The purposes of this study were to establish a new classification of flatfoot by characteristic in frequency distribution of footprint index and to endue the classification with discrepancy in physical fitness.

METHODS/PRINCIPAL FINDINGS

In a longitudinal survey of physical fitness and body structure, weight bearing footprints and 3 physical fitness related tests were measured in 1228 school-aged children. Frequency distribution of initial data was tested by Kolmogorov-Smirnov test for normality and a unique bimodal distribution of footprint index was identified. The frequency distribution of footprint index manifests two distinct modes, flatfoot and non-flatfoot, by deconvolution and bootstrapping procedures. A constant intersection value of 1.0 in Staheli's arch index and 0.6 in Chippaux-Smirak index could distinguish the two modes of children, and the value was constant in different age, sex, and weight status. The performance of the one leg balance was inferior in flatfoot girls (median, 4.0 seconds in flatfoot girls vs. 4.3 seconds in non-flatfoot girls, p = 0.04, 95% CI 0.404-0.484).

DISCUSSION

The natural bimodality lends itself to a flatfoot classification. Bimodality suggests development of the child's foot arch would be a leap from one state to another, rather than a continuous growth as body height and weight. The underlying dynamics of the human foot arch and motor development will trigger research prospects.

Twin extra-high photoluminescence in resonant double-period quantum wells

Twin extra high photoluminescence (PL) in resonant quasi-periodic double-period quantum wells (DPQWs) for higher-generation orders is demonstrated. In the DPQW, the number of maxima in the maximum values of the PL intensity is two, which is different from other quasi-periodic quantum wells (QWs) and traditional periodic QWs. The maximum PL intensity in a DPQW is also stronger than that in a periodic QW under the anti-Bragg condition and that in a Fibonacci QW. Although the peaks of the squared electric field for the twin PL are both located near the QWs, their field profiles are distinct.

Pharmacokinetics and preliminary safety data of a single oral dose of bosentan, a dual endothelin receptor antagonist, in cats

The objective of this study was to evaluate the pharmacokinetic properties and adverse effect profile of single-dose oral bosentan, a dual endothelin receptor antagonist, in healthy cats. Pharmacokinetic parameters were determined following a single mean ± SD oral dose of 3.2 ± 0.6 mg/kg of bosentan in 6 adult cats. Blood was collected for quantification of bosentan via high-performance liquid chromatography with ultraviolet detection. Blood and urine were evaluated for CBC, plasma biochemical profile, and urinalysis, and repeat physical examinations were performed to evaluate for adverse effects. The mean terminal half-life of bosentan was 20.4 ± 17.2 h. The mean peak plasma concentration was 0.49 ± 0.24 g/mL, and the mean time to maximum plasma concentration was 6.8 ± 8.6 h. The area under the curve was 5.14 ± 3.81 h·μg/mL. Oral bosentan tablets were absorbed in cats, and no clinically important adverse events were noted. Further evaluation of repeat dosing, investigation into the in vivo efficacy of decreasing endothelin-1 concentrations in cats, as well as safety in conjunction with other medications is warranted.

Exciton photoluminescence in resonant quasi-periodic Thue-Morse quantum wells

This Letter investigates exciton photoluminescence (PL) in resonant quasi-periodic Thue-Morse quantum wells (QWs). The results show that the PL properties of quasi-periodic Thue-Morse QWs are quite different from those of resonant Fibonacci QWs. The maximum and minimum PL intensities occur under the anti-Bragg and Bragg conditions, respectively. The maxima of the PL intensity gradually decline when the filling factor increases from 0.25 to 0.5. Accordingly, the squared electric field at the QWs decreases as the Thue-Morse QW deviates from the anti-Bragg condition.

DSBCS modulation scheme for hybrid wireless and cable television system

This work develops and demonstrates a double sideband with optical carrier suppression (DSBCS) modulation scheme for a hybrid wireless and cable television system based on a phase modulator (PM) and a polarization beam splitter (PBS). A carrier suppression ratio greater than 20 dB is achieved between two sidebands. In addition, the values of carrier-to-noise ratio, composite second-order and composite triple beat in various channels after 25 km of transmission are higher than the threshold value, and the power penalty of microwave signal in back-to-back and 25 km transmission perform well. Additionally, the constellation diagram of upstream signal is successfully recovered. Above results demonstrate that the proposed scheme is highly promising for practical applications.

Quasi-Bragg conditions in Thue-Morse dielectric multilayers

The existence of quasi-Bragg conditions (QBCs) in Thue-Morse dielectric multilayers (TMDMs), based on high reflectance and large forbidden gap regions in its transmission spectra, is presented. In contrast to a single traditional Bragg condition (TBC) in periodic bilayers, there are three QBCs in TMDMs. The formula for each of these QBCs is derived. The results show that one of these QBCs just overlaps the TBC. However, a singular point with perfect transmission exists in this QBC at the quarter-wave stack, at which high reflection exists in the periodic bilayers.

Strong photoluminescence emission from resonant Fibonacci quantum wells

Strong photoluminescence (PL) emission from a resonant Fibonacci quantum well (FQW) is demonstrated. The maximum PL intensity in the FQW is significantly stronger than that in a periodic QW under the Bragg or anti-Bragg conditions. Moreover, the peaks of the squared electric field in the FQW are located very near each of the QWs. The optimal PL spectrum in the FQW has an asymmetrical form rather than the symmetrical one in the periodic case. The maximum PL intensity and the corresponding thickness filling factor in the FQW become greater with increasing generation order.

Erosive potential of sports beverages

BACKGROUND

Dental erosion is an increasingly prevalent problem in Australia, with the consumption of sports beverages suggested as a risk factor. The aim of this study was to compare the erosive potential of Australian sports beverages.

METHODS

Ten beverages were selected and analysed to determine their pH, titratable acidity and apparent degree of saturation with respect to apatite. The erosive potential of the beverages was measured by human enamel surface loss and surface softening following a 30-minute exposure. A taste testing panel was established to determine the palatability of the sports beverages.

RESULTS

All sports beverages except Sukkie and Endura produced substantial surface loss and surface softening. Compared with the other sports beverages, Sukkie and Endura had a higher pH, lower titratable acidity and higher calcium content. However, Sukkie and Endura were deemed to be less palatable than the other more acidic sports beverages.

CONCLUSIONS

The majority of the sports beverages tested produced dental erosion in this in vitro model. However, two new products Sukkie and Endura have lower erosive potential but also lower palatability.

Differential effects of arsenic on calcium signaling in primary keratinocytes and malignant (HSC-1) cells

Arsenic is highly toxic to living cells, especially skin, and skin cancer is induced by drinking water containing arsenic. The molecular mechanisms of arsenic-induced cancer, however, are not well understood. To examine the initial processes in the development of arsenic-induced cancer, we analyzed calcium signaling at an early stage of arsenic treatment of human primary cells and compared the effects with those observed with arsenic treatment in carcinoma-derived cells. We found that arsenic inhibited inositol trisphosphate receptor (IP3R) function in the endoplasmic reticulum by inducing phosphorylation, which led to decreased intracellular calcium levels. Blockade of IP3R phosphorylation by the serine/threonine protein kinase Akt inhibitor wortmannin rescued calcium signaling. In contrast, arsenic treatment of cells derived from a carcinoma (human squamous carcinoma; HSC-1) for 1h had no obvious effect. Taken together, these results suggest that arsenic-induced reduction in calcium signaling is one of the initial mechanisms underlying the malignant transformation in the development of skin cancer.

The optimal effect site concentration of remifentanil in combination with intravenous midazolam and topical lidocaine for awake fibreoptic nasotracheal intubation in patients undergoing cervical spine surgery

BACKGROUND

Remifentanil has been suggested as a suitable agent for conscious sedation during fibreoptic intubation. We evaluated the optimal effect site concentration (Ce) of remifentanil target-controlled infusion (TCI) for awake nasotracheal fibreoptic intubation in patients undergoing elective cervical spine surgery.

METHODS

Nineteen ASA I-II patients were enrolled. Patients were premedicated with midazolam (<70 kg 1.5 mg; >70 kg 2.0 mg) intravenously. The EC(50) and EC(95) of remifentanil Ce for smooth intubation were determined using Dixon's up-and-down method and isotonic regression. Smooth intubation was considered to have failed when patients exhibited sustained and repetitive coughing with head lift during the procedure. Intubation time, number of attempts, adverse events, and hemodynamic variables were also recorded. Patients were asked to recall the procedure and grade satisfaction at postoperative 24 h.

RESULTS

The EC(50) of remifentanil Ce for smooth intubation was 2.33±0.38 ng·mL-1 as calculated by Dixon's method. The estimated EC(95) of remifentanil Ce was 3.38 (95% confidence interval 2.90-3.46) ng·mL-1. Median intubation time (min) was longer in failed smooth intubation than in smooth intubation (8.0 vs. 6.1, P=0.048). Eleven patients (58%) recalled the procedure and 16 patients (84%) rated their satisfaction score as good or excellent.

CONCLUSION

The estimated EC(95) of remifentanil Ce for smooth nasotracheal fibreoptic intubation with conscious sedation was 3.38 (95% CI 2.90-3.46) ng·mL-1 when used in combination with midazolam and topical lidocaine. Remifentanil TCI may provide a tolerable experience of awake fibreoptic intubation despite the high incidence of recall.