Mallampati Grade Research Articles

Implementation and initial validation of a multicentre obstetric airway management registry

Background: In Africa, maternal mortality after caesarean delivery is 50 times greater than in high-income countries. In South Africa, more than 50% of anaesthesia-related maternal mortality is attributed to failure to protect the airway. We implemented an obstetric airway management registry, to facilitate future improvements in management and outcomes. Methods: A prospective electronic registry was established at three obstetric sites in Cape Town, recording airway management for all general anaesthetics from 20 weeks gestation to seven days post-partum. Perioperative descriptive data are entered using a web-based smartphone-enabled platform. To quantify the reliability of capture, we compared the first 200 records in the registry to theatre logbooks. We used summary statistics to describe our obstetric anaesthesia population, and details relevant to airway management. Results: The first 200 cases were recorded from September 2018 to January 2019. According to theatre logbooks, this represented 80% of cases performed. Major indications for general anaesthesia included severe fetal distress/bradycardia (21%), failed neuraxial technique (19%), coagulopathy (19%), and abnormal placentation (12%). A third of patients had hypertensive disorders of pregnancy, and 6% had imminent/confirmed eclampsia. Forty per cent were in active labour. On airway assessment, Mallampati grade was 3 or 4 in 29% of patients, and mouth opening, thyromental distance and mandibular protrusion limited in 10%, 8% and 8% respectively. Cormack-Lehane grade IIb and III views were encountered in 6% and 2% respectively, with no grade IV views. Desaturation below 90% occurred in 12% of patients. There were two cases (1%) of failed intubation with supraglottic airway rescue, and no emergency surgical airways performed. Conclusion: An obstetric airway management registry was successfully implemented. Clinically significant hypoxaemia occurred commonly during general anaesthesia, with a high incidence of difficult intubation predictors and desaturation. The registry will guide research aimed at improving safety during general anaesthesia in obstetrics.

0688 Evaluation Of A Novel Nasal Airway Stent For Snoring And OSA Treatment By Prospective Japanese Patients

Abstract Introduction This cross-sectional study evaluated a novel nasal airway stent (NAS) in the form of a single-use, disposable device (naśtent® classic, Seven Dreamers Laboratories, Inc., Tokyo, Japan), which represents a significant advancement in NAS technology for the treatment of OSA. Methods 1353 individuals whom were interested in NAS treatment for their snoring and/or OSA were enrolled in this study conducted in different districts in Tokyo, Japan from 8/21/2015 to 3/7/2016. A total of 1335 participants with complete data were included in the final dataset. Collected data included demographic features, self-reported sleep and OSA characteristics, anatomic traits, Epworth Sleepiness Scale (ESS) scores, and NAS tolerance. Results The majority of the participants were middle-aged men (91.5% male, 45±10.8 years) with normal BMI (24.5±5.7). Self-reported sleep was 9-11 hours (0.1%), 7-9 hours (8.2%), 5-7 hours (66.7%), 3-5 hours (22%), 1-3 hours (1.2%), and unreported (1.9%). Their mean Epworth Sleepiness Scale score was 9±5.56, and their peak Mallampati and tonsillar grading scores were 2/4 and 3/5, respectively. Of the participants, 87.4% were aware of possible OSA either by snoring or by prior diagnosis of OSA, and their reasons for desiring use of NAS therapy presented in a similar ratio. Over 80% of the participants had never been treated for their diagnosis of OSA; for those with current or prior treatment for their OSA, 62.9% reported PAP as their primary therapy, followed by oral appliances (25.7%), surgery (0.5%), and other therapies (10.8%). On a scale of 1 to 5 where 5 indicated good tolerance to the NAS, the mean scores were 4±1.3 for easy of insertion and 4±1.2 for convenience of use. Conclusion This large, cross-sectional study indicated that the majority of individuals seeking a novel NAS treatment for their snoring and/or OSA in Tokyo, Japan were middle-aged men with 5-7 hours of self-reported sleep whom had some daytime sleepiness, displayed signs of mild anatomic upper airway narrowing, had not been treated for their OSA, and whom felt that the NAS was easy and convenient to use. Support Seven Dreamers Laboratories, Inc. and WSS ISRTP

The value of improved Mallampati grading combined with NoSAS in OSA screening

Objective:To evaluate the value of improved Mallampati grading combined with NoSAS questionnaire in screening for obstructive sleep apnea （OSA）. Method:A total of 344 patients admitted to our hospital for sleep disorders were studied. All patients were measured for their height, weight, neck circumference and other parameters. NoSAS scores, improved Mallampati grading and polysomnography （PSG） were performed in these patients. According to AHI in PSG monitoring results, patients were divided into non-osa group （AHI<5） 93 cases and OSA group 251 cases. The OSA group were divided into mild （AHI 5-15）, moderate（AHI 16-30） and severe OSA group（AHI>30） according to the PSG result. The ROC curve was plotted to evaluate the screening value of NoSAS and improved Mallampati grading combined with NoSAS for OSA. Result:With the NoSAS score of 8 or 9 as cutoffs for analysis, the sensitivity for OSA was 0.733 and 0.701; the specificity for OSA was 0.538 and 0.624, respectively. The sensitivity and specificity of NoSAS combined with improved Mallampati grading for screening OSA were 0.813 and 0.710, respectively. Conclusion:As a new screening tool, NoSAS questionnaire is simple and convenient, and has certain screening value to OSA. The improved Mallampati grading combined with NoSAS questionnaire can obviously improve the screening sensitivity and specificity of Osa, and has higher application value.

Efficacy of Lignocaine in Three Different Routes In Attenuation of Haemodynamic Response Associated With Endotracheal Intubation : A Comparative Study

Background: Transient haemodynamic instability i.e tachycardia and hypertension is an inevitable outcome of laryngoscopy and endotracheal intubation which can have serious effects in patients with COPD, IHD or hypertension that can lead to ischaemia, infarction, arrhythmia or cardiac arrest in vulnerable patients. Administration of lignocaine is one of the techniques used to attenuate haemodynamic response associated with endotracheal intubation. The present study was designed to compare the changes in blood pressure and heart rate that occur before and after the endotracheal intubation in three different routes intravenous( i.v.) local spray over laryngeal inlet or nebulization.&#x0D; Materials and methods : It was a randomized double blind clinical trial. It was conducted at the Department of Anaesthesiology, Chittagong Medical College Hospital, Chattogram from July 2005 to June 2007. A total of one hundred and fifty adult patients (ASA I, Mallampati grade 1 &amp; 2) scheduled for elective surgery under general anaesthesia wereselected. Patients were randomly allocated in three groups A,B and C, by lottery .Group A received 2% lignocaine i.v., Group B received 10% lignocaine spray over the laryngeal inlet and vocal cords and group C patients were nebulized with 2% lignocaine solution.&#x0D; Results: The rise in Systolic, Diastolic and mean arterial pressure with local spray was significantly lower than with intravenous and nebulized group and the rise in heart rate was significantly lower with local spray group than with nebulization group and intravenous group. Data were processed using software SPSS version 11.5. The test statistics used to analyse the data were Chi-squire(c2) test and Anova.&#x0D; Conclusion: The findings of this study reflects the local spray of 10% lignocaine over laryngeal inlet prior to intubations attenuates the rise in blood pressure and heart rate more than intravenous administration of lignocaine or nebulization of lignocaine.&#x0D; JCMCTA 2019 ; 30 (2) : 86-91

Preoperative Predictors of Response to Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea.

Hypoglossal nerve stimulation (HGNS) is an effective treatment for patients with obstructive sleep apnea (OSA) who fail continuous positive airway pressure (CPAP). We assessed the relationship between patient characteristics and response to HGNS. Retrospective cohort study. Single tertiary care institution. This study included CPAP-intolerant patients with moderate to severe OSA after HGNS system implantation from November 2015 to December 2017. Patient measures, drug-induced sleep endoscopy (DISE) findings, and apnea-hypopnea indices (AHIs) were recorded. Forty-eight patients underwent implantation with the following median measures: age, 66 years; body mass index, 28.6; and neck circumference, 41.0 cm. Patients were classified by Friedman tongue position (II, 27%; III, 56%; IV, 17%) and Mallampati grade (I, 25%; II, 50%; III, 23%; IV, 2%). By DISE, 71% had anterior-posterior palatal collapse. Additionally, 38% had lateral oropharynx collapse; 50%, tongue base collapse; and 27%, epiglottis collapse. Following implantation, median AHI improved from 38.5 to 2.7 (P < .001), and 92% of patients had no worse than mild OSA (8% moderate). Patients with Friedman tongue position grade II/III experienced greater change in AHI as compared with grade IV (94.2% vs 73.8%, P < .001). Patients with Mallampati score I/II experienced greater improvement versus score III/IV (94.7% vs 66.5%, P < .001). No DISE findings, including any obstruction or collapse, were associated with change in AHI. This study further confirms HGNS as an effective treatment of CPAP-intolerant OSA. Office measures such as Friedman tongue position IV and Mallampati III/IV were associated with mildly decreased response. DISE findings were not associated with patient response.

Utility of the modified Mallampati grade and Friedman tongue position in the assessment of obstructive sleep apnea.

The modified Mallampati (MM) grade and Friedman tongue position (FTP) are commonly used scales that assess the oropharynx during evaluation for obstructive sleep apnea (OSA). Though used by many practitioners, there is controversy in the literature regarding their practical utility. The goal of this review will be to review the history of how the MM and FTP were developed, to discuss current evidence for their usefulness in the workup of OSA, and to provide future direction to better understand their utility in the workup of OSA. We searched the literature (PubMed) for the terms "modified Mallampati" and "Friedman tongue position." Articles were selected based on our study objectives emphasizing articles discussing the utility of MM and FTP in managing OSA. MM and FTP have the potential to be useful assessment tools in the evaluation of OSA. When performing this examination, it is important for physicians and other medical providers to understand the pitfalls of the MM and FTP including the potential difficulty in performing the exam and the lack of consistency between examiners in both the terminology and execution of this physical exam finding. Better methods to standardize the assessment are necessary to ensure consistent evaluation among individual examiners while at the same time keeping the method simple and convenient for wide use as a clinical screening tool.

Risk factors affecting the difficulty of fiberoptic nasotracheal intubation.

BackgroundThe success rate of intubation under direct laryngoscopy is greatly influenced by laryngoscopic grade using the Cormack-Lehane classification. However, it is not known whether grade under direct laryngoscopy can also affects the success rate of nasotracheal intubation using a fiberoptic bronchoscpe, so this study investigated the same. In addition, we investigated other factors that influence the success rate of fiberoptic nasotracheal intubation (FNI).MethodsFNI was performed by 18 anesthesiology residents under general anesthesia in patients over 15 years of age who underwent elective oral and maxillofacial operations. In all patients, the Mallampati grade was measured. Laryngeal view grade under direct laryngoscopy, and the degree of secretion and bleeding in the oral cavity was measured and divided into 3 grades. The time required for successful FNI was measured. If the intubation time was > 5 minutes, it was evaluated as a failure and the airway was managed by another method. The failure rate was evaluated using appropriate statistical method. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were also measured.ResultsA total of 650 patients were included in the study, and the failure rate of FNI was 4.5%. The patient's sex, age, height, weight, Mallampati, and laryngoscopic view grade did not affect the success rate of FNI (P > 0.05). BMI, the number of FNI performed by residents (P = 0.03), secretion (P < 0.001), and bleeding (P < 0.001) grades influenced the success rate. The AUCs of bleeding and secretion were 0.864 and 0.798, respectively, but the AUC of BMI, the number of FNI performed by residents, Mallampati, and laryngoscopic view grade were 0.527, 0.616, 0.614, and 0.544, respectively.ConclusionUnlike in intubation under direct laryngoscopy, in the case of FNI, oral secretion and nasal bleeding had a significant effect on FNI difficulty than Mallampati grade or Laryngeal view grade.

24. Predictors of Difficult Laryngoscopy: Comparison of Ratio of Height to Thyromental Distance, Upper Lip Bite Test and Mallampati Grading, A Comparative Analytical Study

24. Predictors of Difficult Laryngoscopy: Comparison of Ratio of Height to Thyromental Distance, Upper Lip Bite Test and Mallampati Grading, A Comparative Analytical Study

Comparative evaluation of conventional to left molar and right molar laryngoscopy and endotracheal intubation

Background: Difficulty in visualizing the glottis may cause difficulty, even failure in endotracheal intubation leading to catastrophes. Difficult laryngoscopy is frequently overcome by using molar approach for laryngoscopy combined with optimal external laryngeal manipulation (OELM). The present study was planned to compare conventional midline approach of laryngoscopy to left molar and right molar approach of laryngoccopy (using Macintosh blade) for endotracheal intubation Material and Methods: This prospective randomized double blind controlled study was conducted on 120 patients of 18-60 years age, belonging to ASA grade I and II of either sex, posted for elective surgery under general endotracheal anaesthesia. Depending on the approach of laryngoscopy used, the patients were randomly divided into three groups of 40 each into Group M (midline approach), Group L (left molar approach) and Group R (right molar approach). Predictors of difficult intubation (Modified Mallampati grading, Thyromental distance, abnormal Dentition) and their association with unsuccessful intubation, Cormack Lehane grading, attempts of intubation, duration of intubation, success rate of intubation, adjuvant measures needed (stylet, retraction of mouth) for intubation were noted. Results: Patients having predictors of difficult intubation had significant risk of unsuccessful intubation with midline approach (p=0.01 for MPG III/IV, p=0.04 for TMD

Superior effect of dexmedetomidine used for induction of general anesthesia: prolonging duration of non-hypoxic apnoea

Objective To evaluate the effect of dexmedetomidine on the duration of non-hypoxic apnoea when used for induction of general anesthesia. Methods Eighty female patients, aged 18-64 yr, with body mass index of 18.5-24.9 kg/m2, of American Society of Anesthesiology physical status Ⅰ or Ⅱ, with Mallampati grade Ⅰ or Ⅱ, scheduled for elective surgery with general anesthesia requiring tracheal intubation, were divided into 2 groups (n=40 each) by a random number table method: dexmedetomidine group (group D) and conventional group (group C). Dexmedetomidine 0.5 μg/kg was intravenously infused over 10 min in group D, and the normal saline 40 ml was intravenously infused in group C. In two groups, pure oxygen 8 L/min was inhaled via the closed mask, 3 min later fentanyl 3 μg/kg, etomidate 0.3 mg/kg and rocuronium 0.6 mg/kg were intravenously injected in turn, assisted ventilation was not performed in this period.The anesthesia machine was immediately connected to perform mechanical ventilation when SpO2 was reduced to 92% after tracheal intubation.Arterial blood samples were collected for blood gas analysis, and PaO2 was recorded at the time of entering the operation room, immediately before inhaling pure oxygen, at the beginning of injecting fentanyl, and when SpO2 was decreased to 92%.The development of adverse cardiovascular events during the trial, and duration of non-hypoxic apnoea were recorded. Results Compared with group C, the incidence of adverse cardiovascular events was significantly decreased, and the duration of non-hypoxic apnoea was prolonged, and no significant change was found in PaO2 at the time of entering the operation room, immediately before inhaling pure oxygen, at the beginning of injecting fentanyl, and when SpO2 was decreased to 92% in group D (P<0.05). Conclusion Dexmedetomidine can prolong the duration of non-hypoxic apnoea and raise the safety of endotracheal intubation during general anesthesia induction when used for induction of general anesthesia. Key words: Dexmedetomidine; Anesthesia, general; Duration of non-hypoxic apnoea

Clinical Prediction Model for Obstructive Sleep Apnea among Adult Patients with Habitual Snoring.

To identify standard clinical parameters that may predict the presence and severity of obstructive sleep apnea/hypopnea syndrome (OSA). Case series with chart review. Tertiary academic medical center. A total of 325 adult patients (274 men and 51 women; mean age, 44.2 years) with habitual snoring completed comprehensive polysomnography and anthropometric measurements, including modified Mallampati grade (also known as updated Friedman's tongue position [uFTP]), tonsil size grading, uvular length, neck circumference, waist circumference, hip circumference, and body mass index (BMI). When the aforementioned physical parameters were correlated singly with the apnea/hypopnea index (AHI), we found that sex, uFTP, tonsil size grading, neck circumference, waist circumference, hip circumference, thyroid-mental distance, and BMI grade were reliable predictors of OSA. When all important factors were considered in a multiple stepwise regression analysis, an estimated AHI can be formulated by factoring sex, uFTP, tonsil size grading, and BMI grade as follows: -43.0 + 14.1 × sex + 12.8 × uFTP + 5.0 × tonsil size + 8.9 × BMI grade. Severity of OSA can be predicted with a receiver operating characteristic curve. Predictors of OSA can be further obtained by the "OSA score." This study has distinguished the correlations between sex, uFTP, tonsil size, and BMI grade and the presence and severity of OSA. An OSA score might be beneficial in identifying patients who should have a full sleep evaluation.

A Comparative Evaluation of Hemodynamic Response and Ease of Intubation using Airtraq and McCoy Laryngoscope.

Background:Various airway gadgets have been devised to overcome difficult airway scenario in anesthesia practice. It includes simple rigid laryngoscope to complex fiber-optic intubating devices; however, there is weak evidence to support the superiority of one device over the other.Aims and Objective:The ease of intubation, time and the hemodynamic variability between two groups during intubation are considered as the primary outcome measures.Materials and Methods:In this prospective study, 60 patients of either sex undergoing elective surgery who required tracheal intubation were included. All the patients of age between 20 and 50 years with the American Society of Anesthesiologists Classes I and II were divided into the following two groups: Group AT (n = 30): the intubation was performed using AT laryngoscope and Group-MC (n = 30); the intubation was performed using MC laryngoscope. The following intubating parameters were recorded: ease of intubation (Grade-I–IV), mean time of laryngoscopy and intubation, Cormack–Lehane grade, and the percentage of glottis opening (POGO) score. The vital parameters such as heart rate (HR) and mean arterial blood pressure (MABP) were recorded only after premedication, and it was taken as the baseline value. These parameters were again recorded at 1 min, 3 min, 5 min, and 10 min after laryngoscopy and intubation. The incidences of sore throat were recorded just before discharge from the recovery room till 24 h of surgery. All these parameters were compared between these two groups using the Student's t-test and Chi-square test.Results:There was no significant difference in age, sex, weight, and Mallampati grading between the two groups. More than 30% of patients in Group AT were intubated without an external aid than the Group MC (P < 0.05). In Group AT, the mean time of intubation was 13.5 ± 5.72 s when compared to 15.63 ± 7.28 s in Group MC (P > 0.05). The Cormack–Lehane grade and POGO score were better in the AT group than that of the MC group. The HR at 1 min in Group AT was 101.83 ± 14.50 and in Group MC, it was 108.93 ± 12.86 (P < 0.05) and after 3 min, it was 98.66 ± 12.60 and 111.53 ± 11.67 (P < 0.05), respectively. The MABP was 107.17 ± 9.03 in Group AT compared to 116 ± 10.12 in Group MC (P < 0.05) at 1 min postintubation. The incidences of sore throat were similar in both the groups.Conclusion:The AT laryngoscope is better than MC in terms of the ease of intubation, better glottis view, and hemodynamic stability. However, the incidences of sore throat in both groups were comparable.

Update Mallampati : Theoretical and practical knowledge of European anesthetists on basic evaluation of airways

In 1985 Mallampati et al. published anon-invasive score for the evaluation of airways (Mallampati grading scale, MGS), which originally consisted of only three different classes and has been modified several times. At present it is mostly used in the version of Samsoon and Young consisting of four different classes. ClassI: soft palate, fauces, uvula, palatopharyngeal arch visible, classII: soft palate, fauces, uvula visible, classIII: soft palate, base of the uvula visible and classIV: soft palate not visible. Nevertheless, other versions of MGS still exist, each having different values for sensitivity and specification. The current opinion is therefore that MGS is no longer useful as a stand-alone predictor but in combination with others it is still part of today's most relevant guidelines, such as those of the American Society of Anesthesiologists (ASA), the UK's Difficult Airway Society (DAS), the European Society of Anaesthesiology (ESA) and the German Society for Anesthesiology and Intensive Care Medicine (DGAI) and must therefore be known by anesthetists. Even in times of sophisticated tools for airway management, the procedure remains ahigh risk, so every anesthetist has to be prepared for and well trained in management of known and unexpected difficult airways. Evaluation of the patient's airway is apart of modern airway management to prevent problems and reduce risk of hypoxia during the procedure. The theoretical knowledge and practical skills of European anesthetists were evaluated at two international congresses, the German Anesthesia Congress (DAC) and Euroanaesthesia 2014. The DAC is an annual meeting of German speaking anesthetists, hosted by the DGAI. The Euroanaesthesia is the annual European pendant hosted by the ESA. Participation was voluntary and only physicians were allowed to take part. Theory was evaluated by aquestionnaire containing open and closed questions for MGS that had to be answered by every participant alone. Apart from theory, a practical evaluation was performed. Every participant had to classify the MGS of ahuman airway model. The model was identical on both congresses. According to the original publication achecklist containing the factors essential for the correct performance was filled out by asupervising experienced anesthetist. During DAC 2014 n = 267 physicians participated in the study, 22 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part. A total of 245 data sets were evaluated. During Euroanaesthesia 2014 n = 298 physicians participated in the study, 68 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part and 230 data sets were evaluated. At the DAC the mean age (± SD) was 44.5 ± 9.5 years, 157 (64.1%) were male and 88 (35.9%) were female. Working experience was trainee anesthetist in 16.7% and other participants were experienced anesthetists. At the ESA the mean age (± SD) was 42.4 ± 9.5 years, 133 (57.8%) were male and 97 (42.2%) female. Trainee anesthetists were 15.2%, the rest were experienced anesthetists. The DAC participants knew Mallampati classes1 (65%) and4 (45%) better than2 and3 and there was no relevant differences to the ESA (close to 30% knew the classes1-4 here). Classification of the airway model was correct in 62% and 67% at DAC and ESA, respectively. Most participants performed the practical evaluation correctly except the sitting position of the model. In agreement with earlier studies, these results show the lack of knowledge in evaluation of airways according to current guidelines of all relevant societies. This is likely to increase preventable risks for patients as unexpected difficult airway management increases the risk for hypoxia and intubation damage.

Prediction of Difficult Airway by Correlating Physical Indices with Maxillo-Pharyngeal Angle, Measured on Lateral Cervical Radiograph-an Analytical Study

Background: The ability to predict difficult laryngoscopy preoperatively allows anaesthesiologists to take precautions to reduce the anesthesia-related risks but till now, no single airway test can provide a high index of sensitivity and specificity for prediction of difficult airway. The present analytical study was aimed to correlate the various physical indices with maxillo-pharyngeal angle, measured on lateral cervical radiograph, for preoperative prediction of difficult airway. &nbsp;Subjects and Methods: After approval from Institutional Ethical Committee and written informed consent, 200 patients of ASA physical status I and II, aged between 18 to 58 years of either gender with BMI &lt;25 Kg/m2, were studied. Patients with any obvious airway related abnormality, restricted mouth opening, short and thick neck, fixation of the trachea, malformation of the skull, teeth or mandible were excluded. Preoperatively, they were assessed for Modified Mallampati grading, thyromental distance, protrusion of jaw and head-neck movements along with Maxillo-pharyngeal angle, measured on lateral cervical radiograph. These parameters were correlated with Cormack Lehane grading during direct laryngoscopy. The observed data were analyzed by using one way analysis of variance (ANOVA) and Pearson’s correlating co-efficient. Results: Modified Mallampati test sensitivity and specificity was found as 39.29% and 65.12% respectively with accuracy of 61.5%. The sensitivity and specificity of Maxillo- Pharyngeal Angle was 85.71 % and 97.09% respectively with accuracy of 95.50 %. Conclusion: The combination of various physical indices along with maxillo-pharyngeal angle in parallel is more sensitive and specific with clinically relevant higher discriminative power.

Different formulae for flexible laryngeal mask airway size selection in endoscopic sinus surgery for China adult male

Objective The objective of this study is to evaluate weight and height-based formulae for selecting the appropriate size of flexible laryngeal mask airway(FLMA) for China adult male in endoscopic sinus surgery(ESS). Methods One hundred adult male patients (ASA class Ⅰ or Ⅱ, age≥18 years) were randomly allocated in group A (weight-based formulae: size 3 for weight<50 kg, size 5 for weight≥70 kg, size 4 for the rest) and group B (weight and height-based formulae: size 3 for weight<50 kg and height<150 cm, size 5 for weight≥70 kg or height≥170 cm, and size 4 for the rest). An experienced user inserted the FLMA after rapid induction. FLMA location was estimated by auscultation, ventilation peak pressure and oropharyngeal leak pressure. Intermittent positive pressure ventilation and total intravenous anesthesia were performed during operation. The primary outcome was concordant with FLMA size used according to the weight-based manufacturers' recommendations or the weight and height-based formulae. The secondary outcome was success rate of the first insertion, attempts of FLMA insertion, ventilation peak pressure, oropharyngeal leak pressure, fiberoptic bronchoscopy score(FOB), FLMA inner contamination by blood and postoperative sore throat score. Measurements of height, weight, the size of the oral opening, Mallampati grades and random grouping were accomplished by the same anesthesia doctor. FLMA insertion and intraoperative and postoperative data collection were accomplished by another anesthesia doctor blindly. Results FLMA was used in 95 patients (50 in group A and 45 in group B) for ventilation during anesthesia. FLMA size 4 was used in 24 patients and size 5 in 71 patients. There were 5 cases (2 in group A and 3 in group B) switched to endotracheal intubation because of dissatisfaction with FLMA location. In group A, 23/27 cases were supposed to be used FLMA size 4/5, actually 15/35 cases were used FLMA size 4/5, the concordance in group A was 72.0%. In group B, 11/34 cases were supposed to be used FLMA size 4/5, actually 9/36 cases were used FLMA size 4/5, the concordance in group B was 91.1%, which was higher than that in group A (P 0.05). Conclusions Weight and height-based formula for the FLMA size selection is more effective than the manufacturer's weight-based formula in ESS for China adult males. These formulae predict FLMA size more accurately and improve the success rate for FLMA insertion. Key words: Flexible laryngeal mask airway; Endoscopic sinus surgery; Adult male; China

EFFECT OF DEXMEDETOMIDINE ON DOSE REQUIREMENT OF PROPOFOL AND THIOPENTONE INDUCTION IN PATIENTS UNDER GENERAL ENDOTRACHEAL ANESTHESIA

Objectives: The present study was undertaken to assess the effect of dexmedetomidine as a premedicant on dose requirement of induction agents, thiopentone and propofol in patients undergoing various surgeries under general endotracheal anesthesia under the bispectral index (BIS) guidance.Methods: A double-blinded randomized controlled study was conducted during the year 2014–2015 among 120 patients aged 18–55 years with American Society of Anesthesiologists’ physical status Score I or II and Mallampati Grades I and II. After obtaining informed consent, all the eligible patients were randomly assigned to one of the four groups each containing 30 patients: Group SP (control group) - saline infusion before induction with propofol, group DP - dexmedetomidine infusion before induction with propofol, group ST (control group) - saline infusion before induction with thiopentone, and group DT - dexmedetomidine infusion before induction with thiopentone.Results: The mean dose of propofol required was 95.0±6.15 mg and 55.0±7.0 mg in group SP and DP, respectively, whereas the requirement of thiopentone was 6.6±0.93 mg/kg in group ST as opposed to 4.8±0.58 mg/kg in group DT. The decrease in the dose requirement in dexmedetomidine groups than the control groups was statistically significant and also dose reduction in dexmedetomidine was more in DP group compared to that in DT group (p&lt;0.001).Conclusion: Dexmedetomidine as a preanesthetic medication significantly decreases intraoperative anesthetic requirement of thiopentone and propofol, and dose requirement is significantly less in case of propofol as compared to thiopentone.

Impacts of different methods in laryngeal mask airway positioning on the airway management of elderly patients with general anesthesia

Objective: By observing the clinical effect of ultrasound, fiberoptic bronchoscopy and traditional standard in positioning the general anesthesia of laryngeal mask ventilation in elderly patients, the superiority of laryngeal mask positioning with visualization technique of ultrasound and fiberoptic bronchoscope on airway management in elderly patients with general anesthesia was analyzed. Methods: One hundred and twenty cases of elderly patients with general anesthesia of laryngeal mask ventilation from the People's Hospital of Yuyao city from October 2016 to October 2017 were selected and randomly divided into 3 groups(n=40)according to American Society of Anesthesiologists (ASA) grading criteria Ⅰ-Ⅲ. Group A: traditional standard positioning laryngeal mask group. Group B: fiberoptic bronchoscope positioning laryngeal mask group. Group C: ultrasound positioning laryngeal mask group. The general information of sex ratio of male and female, mass, and height, and operation type, operation duration, anaesthesia duration, and modified Mallampati grade were observed and compared among the three groups. The number of successful laryngeal mask ventilation after laryngeal mask placement in 3 groups was observed, the laryngeal mask placement time (T(0)) and the normal ventilation time after adjustment (T(1)) in each group were recorded, and the first success rate of laryngeal mask placement, the success rate after adjusting the positioning, and the success rate of re-placement were calculated. Moreover, the mean peak airway pressure at 5 min after operation, the minimum intrathecal injection gas for minimum ventilation (V(min)), the minimum laryngeal mask intravesical pressure (ICP(min)), and the lowest air pressure for oral and pharyngeal leakage (OLP(min)) were recorded. The airway seal pressure (OLP(60)) and the volume of gas injection (V(60)) when the intravesical pressure was 60 cmH(2)O (1 cmH(2)O=0.098 kPa) were used to record the incidence of postoperative laryngeal mask bleeding, cough, nausea and vomiting, and the incidence of pharyngalgia, odynophagia, hoarseness and other related complications after 24 hours of the operation. Results: There was no significant difference in general information, airway evaluation and anesthesia operation among the three groups (all P>0.05). The incidence of intraoperative laryngeal mask bleeding in group B and C was 7.9% and 2.6% respectively, the incidence of odynophagia at 24 hours after operation was 5.3% and 0 respectively, and the incidence of pharyngalgia and hoarseness was 18.4% and 7.9% respectively, less than that in group A (24.2%, 12.1% and 36.3%). The difference was statistically significant (χ(2)=8.900, 6.880, 9.000, P<0.05). The success rate of adjustment and positioning after the placement of laryngeal mask was 84.2% and 94.7% respectively in group B and C, higher than that in group A of 72.7%, and the difference was statistically significant (χ(2)=6.500, P<0.05). The lowest laryngeal mask intralaryngeal pressure for ventilation in group B and C was (35.39±4.67) cmH(2)O and (32.61±3.22) cmH(2)O, lower than that in group A of (39.30 ± 5.93) cmH(2)O, the intralaryngeal pressure was 60 cmH(2)O, and the airway seal pressure was (25.82±4.48) cmH(2)O and (28.34±6.99) cmH(2)O, higher than that in group A of (22.45±4.98) cmH(2)O, which was significantly different (F=18.200, 9.720, P<0.05). Conclusions: In elderly patients with general anesthesia, it is feasible to manage the airway by ultrasound or fiberoptic bronchoscopy with laryngeal mask. Ultrasound positioning laryngeal mask improves the accuracy of the intraoperative ventilation, and reduces the incidence of postoperative airway related complications.

Formulation of a multivariate predictive model for difficult intubation: A double blinded prospective study.

Background and Aims:Various models were devised for prediction of difficult intubation but have low positive predictive value, sensitivity and specificity. We aimed to predict difficult intubation from various airway predictive indices, in isolation and combination, and to formulate a multivariate model that can aid in accurate prediction of difficult intubation.Material and Methods:A prospective double blinded study was conducted on 500 adult patients scheduled for elective surgery under general anaesthesia. Preoperatively, they were assessed for airway screening tests. After standardized induction of anaesthesia, laryngoscopic view was classified according to the Modified Cormack and Lehane (MCL) classification. Variables’ association with intubation findings was evaluated using Chi-square statistic. Stepwise logistic regression identified the multivariate independent predictors of difficult intubation and combinations were made using forward selection process. 8 models were formulated and a receiver-operating characteristic (ROC) curve worked out for them. Sensitivity and specificity analysis validated the final model.Results:Age, sex, weight, BMI, snoring, obstructive sleep apnea (OSA), diabetes, hypertension, upper lip bite test (ULBT), Mallampati grade (MPS), thyromental distance (TMD), sternomental distance (SMD), neck movements (NM), neck circumference (NC) and inter-incisor gap (IIG) had significant correlation with difficult intubation. Based upon sensitivity and specificity analysis, model comprising of MPS, NM, NC and SMD was found to be most accurate. It had highest sensitivity 80%, specificity 87% and area under curve 0.90, thus validating the model.Conclusions:Our study found that a combination of MPS, SMD, NM and NC permits reliable, accurate and quick preoperative prediction of difficult intubation.

Assessment of the effect of supine posture and phonation on modified mallampati grading and its applicability in prediction of difficult airway

Introduction: As it is not always possible to do Modified Mallampati Test (MMT) in sitting position, this study was designed to test the effect of supine position and phonation on classical MMT and use of such effect in predicting difficult laryngoscopical view or difficult intubation. Aim: To know the effect of phonation and supine position on classical MMT grade and to establish usefulness of modification in predicting difficult laryngoscopy or intubation. Objectives: 1. To compare classical MMT grades with those obtained in supine position with or without phonation. 2. To correlate MMT gradings obtained in all the three variations with Modified Cormack Lehane (MCML) grading and actual difficult intubations to obtain their powers in predicting difficult laryngoscopic view and difficult intubations. Material and Methods: A prospective observational study, conducted at a tertiary care hospital.Consenting, 130 adults, undergoing elective surgical procedures were included. MMT score in sitting position, in supine position with or without phonation was recorded in the preoperative area and MCML grading and actual difficulty for intubation were noted at the time of intubation. Emergency cases and patients with altered airway were excluded.Statistics: 'Kappa' agreement analysis was done to compare the agreement between various scores. Sensitivity, specificity, positive predictive value and negative predictive values were calculated. Results: Supine posture without phonation worsens the classical Mallampati grading whereas supine posture with phonation improves it. MMT in sitting and in supine position without phonation have very good agreement with each other in predicting difficult laryngoscopy and intubation. Conclusions: When the patient cannot sit for examination, MMT scoring can be done in supine position without phonation. Mallampati score in supine position with phonation is not recommended due to high false negatives.

A randomised comparative study on customised versus fixed sized pillow for tracheal intubation in the sniffing position by Macintosh laryngoscopy.

Background and Aims:The sniffing position has been most commonly used for positioning of the head and neck to facilitate tracheal intubation. However, the optimum degree of head elevation for the optimal laryngeal view is not well studied, especially in non-Western countries. The present study was aimed to compare the use of a fixed height pillow versus a customised pillow (CP) height for head elevation, in terms of glottis visualisation and time required for tracheal intubation.Methods:With research and ethics committee approval from the institute, this randomised study was conducted among patients of both sexes aged 16 years or more and American Society of Anesthesiologists physical Status I to IV. A total of 134 patients were randomly allocated into routinely used fixed-sized pillow (FP) and CP group (to achieve horizontal alignment of external auditory meatus [EAM] and sternal notch). Primary and secondary outcomes were Cormack–Lehane (C–L) grade of glottic visualisation and time required for tracheal intubation, respectively. They were compared using unpaired t-test and Fisher's exact test as applicable; P < 0.05 was considered statistically significant.Results:One hundred and nineteen patients completed the study. Both groups were similar in terms of demographic and external airway measurements. The mean ± standard deviation height of pillow required in Group CP was 6.26 ± 0.97 cm. Group FP had C–L Grade 3 view more often than Group CP (28.33% vs. 13.56%). In patients with modified Mallampati (MMP) Grade ≥3, the C–L grades and time required for intubation were both significantly lower in group CP. The time required for tracheal intubation was significantly lower in group CP (P = 0.04), even though the C–L grades were similar.Conclusion:Customising pillow for head elevation to horizontally align the EAM and the sternal notch gives better glottic visualisation and intubating conditions in patients with higher MMP grades.