***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Awake fibreoptic intubation ( AFOI ) is a technique used in patients with difficult airways . This study compares the suitability of remifentanil target-controlled infusion ( TCI ) to propofol TCI for conscious sedation during AFOI in patients with bona fide difficult airways . METHODS We recruited 24 , ASA I-III patients , who were undergoing sedation for elective AFOI . Patients were r and omized to one of the two groups , Group P ( n=10 ) received propofol TCI and Group R ( n=14 ) received remifentanil TCI . Primary outcome measures were conditions achieved at endoscopy , intubation , and post-intubation , which were grade d using scoring systems . Other parameters measured were the endoscopy time , intubation time , and number of attempts at intubation . A postoperative interview was conducted to determine recall of events and level of patient satisfaction . RESULTS Endoscopy scores ( 0 - 5 ) and intubation scores ( 0 - 5 ) were significantly different [ Group P 3 ( 1 - 4 ) vs Group R 1 ( 0 - 3 ) P<0.0001 , Group P 3 ( 2 - 4 ) vs Group R 1 ( 0 - 3 ) P<0.0001 , respectively ] ; with much better conditions in Group R , endoscopy times and intubation times were also significantly different , being shorter in Group R ( P<0.007 and P<0.023 , respectively ) . Patient tolerance of the procedure , judged by the discomfort scores ( P<0.004 ) and the post-intubation scores ( P<0.08 ) , was significantly better in Group R. The level of recall for events was higher in Group R. However , there were no significant differences in the patient satisfaction scores . CONCLUSIONS Remifentanil TCI appears to provide better conditions for AFOI when compared with propofol TCI . The disadvantage of remifentanil in this setting may be a higher incidence of recall Cricothyroid membrane injections and the application of a coarse fiberoptic bronchoscope ( FOB ) below the vocal cords for topical anesthesia have a number of limitations for certain patients . Thus , the aim of the present observational study was to assess the effect of a novel modified topical anesthesia method using the effective sedation drugs , remifentanil ( Rem ) or dexmedetomidine ( Dex ) , during awake fiberoptic orotracheal intubation ( AFOI ) . In total , 90 adult patients , who had been classified as American Society of Anesthesiologists I – II , were included in the study . The patients had anticipated difficult airways and were to undergo orotracheal intubation for elective surgery . The patients were enrolled in the double-blinded r and omized pilot study and received Rem or Dex for sedation during the modified AFOI procedure . The two groups received 2 % lidocaine for topical anesthesia via an epidural catheter , which was threaded through the suction channel of the FOB . The main clinical outcomes were evaluated by grade d scores representing the conditions for intubation and post-intubation . Additional parameters analyzed included airway obstruction , hemodynamic changes , time required for intubation , amnesia level and subjective satisfaction . All 90 patients were successfully intubated using the modified AFOI technique . The comfort scores and airway events during intubation did not significantly differ between the two groups . However , the Rem group experienced less coughing , and less time was required for tracheal intubation when compared with the Dex group . No statistically significant differences were observed in the changes to the mean arterial pressure and heart rate at any time point between the two groups . Therefore , the current study demonstrated that the modified AFOI method is feasible and effective for difficult airway management , and that Dex and Rem exhibit similar efficacy as adjuvant therapies Fibreoptic intubation is a valuable modality for airway management . This study aim ed to compare the effectiveness of dexmedetomidine vs target controlled propofol infusion in providing sedation during fibreoptic intubation . Forty patients with anticipated difficult airways and due to undergo tracheal intubation for elective surgery were enrolled and r and omly allocated into the dexmedetomidine group ( 1.0 μg.kg−1 over 10 min ) ( n = 20 ) or the propofol target controlled infusion group ( n = 20 ) . Intubating conditions and patient tolerance as grade d by a scoring system were evaluated as primary outcomes . Intubation was successful in all patients . Satisfactory intubating conditions were found in both groups ( 19/20 in each group ) . The median ( IOR [ range ] ) comfort score was 2 ( 1–2 [ 1–4 ] ) in the dexmedetomidine group and 3 ( 2–4 [ 2–5 ] ) in the propofol group ( p = 0.027 ) , favouring the former . The dexmedetomidine group experienced fewer airway events and less heart rate response to intubation than the propofol group ( p < 0.003 and p = 0.007 , respectively ) . Both dexmedetomidine and propofol target‐controlled infusion are effective for fibreoptic intubation . Dexmedetomidine  allows better tolerance , more stable haemodynamic status and preserves a patent airway Background : Awake fibreoptic  nasotracheal intubation ( FNI ) is performed in potentially difficult airways under local anaesthesia . This observer‐blinded study was design ed to evaluate the efficacy of upper airway anaesthesia produced by nebulized lignocaine against combined regional block ( CRB ) for awake FNI BACKGROUND : We design ed this r and omized , double-blind clinical study to compare the safety and efficacy of 2 % and 4 % lidocaine during airway topical anesthesia with a spray-as-you-go technique via the fiberoptic bronchoscope . METHODS : Fifty-two adult patients with a difficult airway were r and omly assigned to 1 of 2 study groups to receive 2 % ( Group 1 ) or 4 % lidocaine ( Group 2 ) by a spray-as-you-go technique with the fiberoptic bronchoscope , in a double-blind manner . After airway topical anesthesia , awake fiberoptic orotracheal intubation ( FOI ) was performed . Level of sedation , time for each lidocaine spray in different targeted areas , total times for airway sprays , total dosages of lidocaine used for airway sprays , intubation times , and number of intubation attempts were noted . An independent investigator scored patients ’ comfort during airway topical anesthesia , patients ’ reaction , coughing severity , and intubating condition during awake FOI , and observed changes of arterial blood pressure and heart rate during each stage in the airway manipulation process . Serial blood sample s were obtained for analysis of plasma lidocaine concentrations . RESULTS : Except for the total dosages and plasma concentrations of lidocaine , there were no significant differences in any of the observed variables between groups . All patients exhibited excellent or acceptable intubating conditions . The total dosages of lidocaine  were significantly smaller in Group 1 ( 3.4 ± 0.6 mg/kg ) than in Group 2 ( 7.1 ± 2.1 mg/kg ) . The plasma lidocaine concentrations in all observed points after the supraglottic sprays were larger in Group 2 than in Group 1 . CONCLUSIONS : Both 2 % and 4 % lidocaine administered topically by a spray-as-you-go technique can provide clinical ly acceptable intubating conditions for awake FOI in se date d patients with a difficult airway . As compared with 4 % lidocaine , however , 2 % lidocaine requires a smaller dosage and results in lower plasma concentrations Background and Aims : Ultrasonography has emerged as a novel , portable , non-invasive tool encouraging airway assessment and procedural interventions . This study assesses the feasibility of ultrasound for block of internal branch of superior laryngeal nerve ( ibSLN ) block during upper airway anaesthesia to aid awake fibre-optic intubation . Methods : Forty American Society of Anesthesiologists ' physical status I – II patients , aged 18–60 years , deemed to have a difficult airway ( modified Mallampati class III – IV or inter-incisor distance < 2.5 cm ) and planned for awake fibre-optic intubation were r and omised to either  l and mark group ( L , n = 20 ) or  ultrasound  group ( U , n = 20 ) . All patients received nebulised 4 % lignocaine ( 3 mL ) and transtracheal injection 3 mL 2 % lignocaine . Group L received l and mark-guided bilateral ibSLN block with 1 mL 2 % lignocaine . Group U received bilateral ibSLN block with 1 mL 2 % lignocaine using a high-frequency ultrasound transducer to define the SLN space . The primary objective was assessment of quality of airway anaesthesia . Secondary objectives were time for intubation , haemodynamic parameters and patient perception of discomfort during procedure . Results : The quality of anaesthesia was significantly better in Group U than in Group L ( P < 0.001 ) . The mean time for intubation was shorter in Group U ( 71.05 ± 9.57 s ) compared to Group L ( 109.05 ± 30.09 s , P < 0.001 ) . Heart rate , mean arterial pressure and patient perception of discomfort were significantly increased in Group L. Conclusion : Ultrasound for ibSLN block as a part of preparation for awake fibre-optic intubation improves quality of airway anaesthesia and patient tolerance The purpose of this study was to compare the effects of propofol and remifentanil target-controlled infusion ( TCI ) on awake fiber-optic intubation with limited local anesthesia . 36 patients requiring fiberoptic intubation were r and omized to receive  propofol ( P ) or remifentanil ( R ) effect-site TCI . Target concentrations , sedation levels , pulse oximetry , hemodynamic change , duration , number of adjustments , intubating conditions and recall after surgery were recorded at each stage . The results showed that the target intubation concentration of remifentanil was very close to the sedation concentration but that the intubation concentration of propofol was more than double its sedation concentration ( 5.83±1.46 μg/ml vs. 2.60±0.47 μg/ml , respectively ) . Vocal cord opening was significantly better in remifentanil-treated patients . More adjustments and a longer duration were required in propofol-treated patients . Recall was significantly more frequent in remifentanil-treated patients . We concluded that compared to TCI propofol , TCI remifentanil can provide safer and better intubating conditions for fiber-optic intubation with limited local anesthesia Background and Aims : In patients undergoing surgery for cervical myelopathy , induction of general anesthesia can induce systemic arterial hypotension that may worsen spinal cord hypoperfusion and precipitate spinal injury . In this r and omized , controlled , clinical trial study , we compared the hemodynamic changes related to anesthesia induction with intravenous ( IV ) propofol- and sevoflurane-based inhalational induction in patients undergoing fiberoptic intubation for cervical spine surgery . Material and Methods : A total of 72 patients were studied . Hemodynamic effects were assessed measuring mean arterial pressure ( MAP ) , and the echocardiographic evaluation of the left ventricular function . A Student 's t-test with Bonferroni correction or Chi-squared test was used , when appropriate , to assess differences in hemodynamic ( extent of MAP drop and incidence of episodes of severe arterial hypotension ) and other variables ( occurrence and duration of episodes of apnea ) . Results : Patients assigned to total IV anesthetic approach had a lower MAP , and more significant changes in cardiac function compared to those who received the inhalational approach ( 68.1 ± 9.3 mmHg vs. 75.5 ± 10.3 mmHg ; 25 % vs. 5.5 % ) . Conclusion : Anesthesia induction with both propofol or sevoflurane is safe and effective . However , total IV anesthesia induction is associated with more pronounced MAP drop which can worsen spinal cord hypoperfusion Background : Awake fiberoptic intubation ( AFOI ) is a recommended technique for anticipated difficult airway . An ideal regime should provide patient comfort , cooperation , amnesia , hemodynamic stability , and blunt airway reflexes and maintain a patent airway with spontaneous ventilation . The aim of our study was to compare intubation conditions between dexmedetomidine and fentanyl – midazolam combination during AFOI . Methods : This prospect i ve , r and omized study was conducted on a total of sixty patients of the American Society of Anesthesiologists physical status I and II of either sex , in the age group of 18–60 years having predicted difficult intubation undergoing elective surgeries and the patients were allocated to two groups of thirty patients each . After premedication and topicalization of airways , dexmedetomidine group ( Group I , n = 30 ) received dexmedetomidine 1 μg/kg over 10 min and midazolam – fentanyl group ( Group II , n = 30 ) received fentanyl 2 μg/kg plus midazolam 0.02 mg/kg over 10 min . Adequacy of intubation condition was evaluated by cough score and postintubation score . Incidence of desaturation , hemodynamic changes , and sedation using Ramsay sedation scale were noted 
    Output:
    
All evaluated methods to achieve local anesthesia performed similarly well .
No differences were observed in success rate with different sedatives .
A high degree of efficacy and safety was observed with minimal differences among different protocol s ; dexmedetomidine might offer a better safety profile compared to other sedatives