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1.  Comparison of clinical performance of the I-gel with LMA proseal 
To compare insertion characteristics of 2 different supraglottic devices [I-gel and Proseal laryngeal mask airway (PLMA)] and to observe any associated complications.
Study Design:
This prospective, randomized study was conducted in 80 patients [Group I - I-gel insertion (n = 40) and Group P - LMA Proseal insertion (n =40)] of ASA grades I/II, of either sex in the age group 18-65 years. Both groups were compared with respect to ease of insertion, insertion attempts, fiberoptic assessment, airway sealing pressure, ease of gastric tube placement, and other complications.
Materials and Methods:
All patients were asked to fast overnight. Patients were given alprazolam 0.25 mg orally at 10 p.m. the night before surgery and again 2 hours prior to surgery with 1-2 sips of water. Glycopyrrolate 0.2 mg, metoclopramide 10 mg, and ranitidine 50 mg were administered intravenously to the patients 45 minutes prior to the surgery. Once adequate depth of anesthesia was achieved either of the 2 devices, selected using a random computerized table, was inserted by an experienced anesthesiologist. In group I, I-gel was inserted and in patients of group P, PLMA was inserted.
Statistical Analysis:
Student t-test and Mann-Whitney test were employed to compare the means; for categorical variables, Chi-square test was used.
Mean insertion time for the I-gel (11.12 ± 1.814 sec) was significantly lower than that of the PLMA (15.13 ± 2.91 sec) (P = 0.001). I-gel was easier to insert with a better anatomic fit. Mean airway sealing pressure in the PLMA group (29.55 ± 3.53 cm H2O) was significantly higher than in the I-gel group (26.73 ± 2.52 cm H2O; P = 0.001). Ease of gastric tube insertion was significantly higher in the I-gel group (P = 0.001). Incidence of blood staining of the device, sore throat and dysphagia were observed more in PLMA group. No other complications were observed in either of the groups.
PMCID: PMC3590543  PMID: 23493414
Airway sealing; cuff pressure; fiberoptic; I-gel; insertion; leak; proseal laryngeal mask airway
2.  Comparison of oral fiberoptic intubation via a modified guedel airway or a laryngeal mask airway in infants and children 
Though fiberoptic intubation (FOI) is considered the gold standard for securing a difficult airway in a child, it may be technically difficult in an anesthetized child. The hypothesis for this study was that it would be easier to perform FOI via a laryngeal mask airway (LMA) than a modified oropharyngeal airway with the advantage of maintaining anesthesia and oxygenation during the process.
Materials and Methods:
30 children aged 6 months to 5 years undergoing elective surgery under general anesthesia were randomized to two groups to have fiberoptic bronchoscope (FOB) guided intubation either via a modified Guedel airway (FOB-ORAL) or a classic LMA (FOB-LMA). In the FOB-LMA group, the LMA was removed when a second smaller endotracheal tube was anchored to the proximal end of the tracheal tube in place.
Oral fiberoptic intubation was successful in all children. The first attempt success rate was 11/15 (73.33%) in the FOB-LMA group and 3/15 (20%) in the FOB-ORAL group (P = 0.012). Subsequent attempts at intubation were successful after 90° anticlockwise rotation of the endotracheal tube over the FOB. The time taken for fiberoptic bronchoscopy was significantly less in FOB-LMA group (59.20 ± 42.85 sec vs 108.66 ± 52.43 sec). The incidence of desaturation was higher in the FOB-ORAL group (6/15 vs 0/15).
In children, fiberoptic bronchoscopy and intubation via an LMA has the advantage of being easier, with shorter intubation time and continuous oxygenation and ventilation throughout the procedure. Removal of the LMA following intubation requires particular care.
PMCID: PMC3590542  PMID: 23493291
Difficult; equipment; fiberoptic bronchoscope; intubation; laryngeal mask airway; modified oropharyngeal Guedel airway; tracheal
3.  Insertion of LMA Classic™ with and without digital intraoral manipulation in anesthetized unparalyzed patients 
The standard recommended insertion technique for LMA Classic™ requires the insertion of index finger into the oral cavity. Several anesthesiologists are reluctant to do this. We conducted this study to evaluate the modified technique of insertion of LMA Classic™ (not requiring insertion of fingers into the patient's mouth) against the standard index finger insertion technique.
Materials and Methods:
This prospective, randomized, comparative study was conducted on 200 consenting patients. Patients suitable for anesthetic with LMA Classic™ were randomized to standard technique group (standard insertion technique) and modified technique group (technique not requiring digital intraoral manipulation). Laryngeal mask airway (LMA) was inserted by five designated anesthesiologists. Anesthetic protocol was standardized. Time taken to achieve an effective airway, ease of insertion, glottic view obtained through LMA, and incidence of sore throat were assessed.
Patient characteristics and duration of surgery were comparable between the groups. Time to achieve an effective airway was comparable [18.5 (8) s with standard technique and 19.7 (10) s with modified technique; data are mean (standard deviation)]. Ease of insertion (92 easy with standard technique and 91 easy with modified technique), success rate (99% in both the groups), glottic view with fiberoptic bronchoscope, and sore throat incidence (six patients with standard technique and eight patients with modified technique) were comparable. The first attempt success rate was significantly higher with the standard technique (98 patients in the standard technique group and 91 patients in the modified technique group).
LMA Classic™ can be inserted successfully without the need to insert index finger into patient's mouth, though the first attempt success rate is higher with the standard technique.
PMCID: PMC3511946  PMID: 23225929
Insertion technique; LMA Classic™ Supraglottic device
4.  Is I-gel airway a better option to endotracheal tube airway for sevoflurane-fentanyl anesthesia during cardiac surgery? 
Anesthetists used lower doses of fentanyl, successfully with hemodynamic control by titrating volatile anesthetic agents or vasodilators for fast-tracking in cardiac surgery.
Lower total doses of anesthetics and fentanyl could be required with hemodynamic control by use of supraglottic devices than endotracheal tube (ETT) and helps in fast-tracking.
A prospective randomized observational clinical trial study.
The authors compared the utility of I-gel airway with a conventional ETT during the induction and maintenance of anesthesia with sevoflurane and fentanyl in adults undergoing cardiac surgery.
Patients and Methods:
A total of 49 adult patients underwent cardiac surgery were randomized into two groups according to the airway management: I-gel group (n = 23) and ETT group (n = 26). Doses of fentanyl and hemodynamic parameters (heart rate [HR], mean arterial pressure [MAP] central venous pressure [CVP], pulmonary artery pressure [PAP], and pulmonary capillary wedge pressure [PCWP]) were recorded preoperative, 5 min following tracheal intubation or I-gel airway insertion, after skin incision, after stenotomy, and after weaning off bypass.
None of the patients in the I-gel group required additional doses of fentanyl during the I-gel insertion, compared with 74% of the patients during laryngoscopy and endotracheal insertion in the ETT group, for an average total dose of 22.6 ± 0.6 μg/kg. The MAP and HR did not significantly differ from the baseline values at any point of measurement in either group. Furthermore, CVP, PAP, and PCWP measured during the procedure were significantly lower in I-gel group than ETT group. Extubation required more amount of time in ETT than I- gel group.
The I-gel airway is well-tolerated by adult patients undergoing cardiac surgery, and requires lower total doses of anesthetics than endotracheal intubation with hemodynamic control and helps in fast-tracking.
PMCID: PMC4173615
Cardiac surgery; endotracheal tube; laryngeal mask airway; sevoflurane-fentanyl anesthesia
5.  Comparison of three supraglottic devices in anesthetised paralyzed children undergoing elective surgery 
Saudi Journal of Anaesthesia  2012;6(3):224-228.
The newest variation of the i-gel supraglottic airway is a pediatric version.
This study was designed to investigate the usefulness of the size 2 i-gel compared with the ProSeal laryngeal mask airway (PLMA) and classic laryngeal mask airway (cLMA) of the same size in anesthetized, paralyzed children.
Settings and design:
A prospective, randomized, single-blinded study was conducted in a tertiary care teaching hospital.
Ninety ASA grade I–II patients undergoing lower abdominal, inguinal and orthopedic surgery were included in this prospective study. The patients were randomly assigned to the i-gel, PLMA and cLMA groups (30 patients in each group). Size 2 supraglottic airway was inserted according to the assigned group. We assessed ease of insertion, hemodynamic data, oropharyngeal sealing pressure and postoperative complications.
There were no differences in the demographic and hemodynamic data among the three groups. The airway leak pressure of the i-gel group (27.1±2.6 cmH2O) was significantly higher than that of the PLMA group (22.73±1.2 cmH2O) and the cLMA group (23.63±2.3 cmH2O). The success rates for first attempt of insertion were similar among the three devices. There were no differences in the incidence of postoperative airway trauma, sore throat or hoarse cry in the three groups.
Hemodynamic parameters, ease of insertion and postoperative complications were comparable among the i-gel, PLMA and cLMA groups, but airway sealing pressure was significantly higher in the i-gel group.
PMCID: PMC3498659  PMID: 23162394
Classic laryngeal mask airway; i-gel; pediatric patients; ProSeal laryngeal mask airway
6.  Oral Appliances for Obstructive Sleep Apnea 
Executive Summary
The objective of this review was to determine the clinical effectiveness of oral appliances compared to ‘no treatment’, continuous positive airway pressure (CPAP), or surgery for the management of obstructive sleep apnea (OSA).
Clinical Need: Condition and Target Population
OSA is characterized by repeated occurrences of upper airway collapse and obstruction during sleep. The condition leads to excessive daytime sleepiness, diminished quality of life, and increased risks of accidents, cardiovascular disease and death. In the general population, the prevalence of OSA is estimated to be 4% in men and 2% in women. Risk factors for OSA include obesity, male gender, increasing age, alcohol use, sedative use, and a family history of OSA.
Description of Oral Appliances
Oral appliances for OSA fall into two broad categories: mandibular advancement splints (MAS), also known as mandibular repositioning devices, and tongue repositioning or retaining devices. The aim of MAS devices is to advance the mandible forward slightly to enlarge the upper airway and prevent it from collapsing. Similarly, tongue repositioning devices suction the tongue forward to prevent it from falling back and obstructing the airway during sleep.
The alternatives to oral appliances include continuous positive airway pressure (CPAP) devices, surgery, drug therapy, positional devices, and lifestyle modification. CPAP is the gold standard of treatment, but despite its effectiveness, compliance rates for CPAP have declined because required systems are noisy and because wearing the mask can be uncomfortable, causing claustrophobia in some users.
Evidence-Based Analysis Methods
Research Questions
Are oral appliances effective in improving sleep-disordered breathing in patients with OSA compared to alternative treatments?
Are there safety concerns with oral appliances?
What is the evidence regarding patient preference, quality of life, and compliance for oral appliances?
If effective, are oral appliances cost effective?
Literature Search
A literature search was conducted up to February 2009. Systematic reviews, meta-analyses and randomized controlled trials (RCTs) with more than 20 adults with OSA were eligible for inclusion. The primary outcomes of interest were the Apnea Hypopnea Index (AHI), measures of daytime sleepiness, patient preference, compliance, and adverse events.
Summary of Findings
Five systematic reviews and 16 RCTs that met the inclusion criteria were identified. The systematic reviews consistently concluded that CPAP was more effective than oral appliances at improving sleep disordered breathing, although there may be a niche area for the latter, especially among those with mild OSA as CPAP is difficult to tolerate by some users.
Based on the results of the RCTs analyzed for this review, MAS devices are less effective than CPAP when AHI is used as the outcome of interest. MAS devices were shown to decrease AHI levels, but whether this reduction is clinically meaningful is uncertain.
The Epworth Sleepiness Scale (ESS) was not able to achieve statistical significance in comparisons of MAS versus CPAP and MAS versus placebo. Nonetheless, after treatment with either MAS or CPAP, patients seem to be able to achieve normal ESS levels. The ESS has substantial limitations including its subjective nature and low construct validity (i.e. it is unclear if the scale is an accurate measure of sleepiness).
Adverse events among patients with MAS devices in the RCTs were common, but mostly mild and transient. Jaw discomfort was the most commonly reported adverse event.
Based on the results of the RCTs, compliance does not seem to be better or worse with MAS or CPAP. Similarly, there is no clear patient preference for MAS or CPAP among the studies reporting preference and satisfaction.
Obstructive sleep apnea, oral appliances, mandibular advancement splints, tongue repositioning devices
PMCID: PMC3377505  PMID: 23074535
7.  Comparison of i-gel™ supraglottic device with classic laryngeal mask airway in anesthetized paralyzed children undergoing elective surgery 
The newest variation of the i-gel supraglottic airway is a pediatric version.
This study was designed to investigate the usefulness of the size 2 i-gel compared with the classic laryngeal mask airway (cLMA) of the same size in anesthetized, paralyzed children.
Settings and Design:
A prospective, randomized, single-blinded study was conducted in tertiary care teaching hospital.
Subject and Methods:
Sixty ASA grade I–II patients undergoing lower abdominal, inguinal, and orthopedic surgery were included in this prospective study. The patients were randomly assigned to i-gel and cLMA groups (30 patients in each group). Size 2 supraglottic airway was inserted according to the assigned group. We assessed ease of insertion, hemodynamic data, oropharyngeal sealing pressure, and postoperative complications.
Statistical Analysis Used:
Parametric data were analyzed with the unpaired t-test and non-parametric data were analyzed with the Chi-square test. Unless otherwise stated, data are presented as mean (SD). Significance was taken as P < 0.05.
There were no differences in the demographic and hemodynamic data among the two groups. The airway leak pressure of the i-gel group (26.1 ± 2.4 cm H2O) was significantly higher than that of the cLMA group (22.64 ± 2.2 cm H2O). The success rates for first attempt of insertion were similar among the two devices. There were no differences in the incidence of postoperative airway morbidity among the two groups.
Hemodynamic parameters, ease of insertion, and postoperative complications were comparable between the i-gel and cLMA groups, but airway sealing pressure was significantly higher in i-gel group.
PMCID: PMC4173459
Classic laryngeal mask airway; i-gel; pediatric patients
8.  Postoperative airway management after nasal endoscopic sinus surgery: A comparison of traditional nasal packing with nasal airway 
Nasal packing after the nasal surgery can be extremely hazardous and can lead to airway complications such as dyspnea and respiratory obstruction.
The present study aimed at comparing the traditional nasal packing with nasal airway during the immediate postoperative period in patients undergoing fibreoptic endoscopic sinus surgery (FESS) under general anaesthesia (GA) with regards to airway management.
Materials and Methods:
The study groups consisted of 90 ASA grade I and II patients aged 16 to 58 years who underwent FESS under GA. Patients were randomly assigned into three groups: Group NP, UA and Group BA of 30 patients each. At the end of surgery, Group NP patients were managed with traditional bilateral nasal packing while a presterilized 5 mm ID uncuffed ETT was cut to an appropriate size and inserted into one of the nostrils in UA and bilaterally in BA group patients. During postoperative period following parameters and variables were observed over the next 24 hours: Any respiratory distress or obstruction, pain and discomfort, oxygen saturation, heart rate, blood pressure, bleeding episode, ease of suctioning through nasal airway, anaesthesiologists and surgeons satisfaction during postoperative period, discomfort during removal of nasal airway and any fresh bleeding episode during removal of nasal airway. The data was compiled and analyzed using Chi-square test and ANOVA with post-hoc significance. Value of P < 0.05 was considered significant and P < 0.0001 as highly significant.
The post-op mean cardio-respiratory parameters showed significant variations among NP group (P < 0.05) and the patient of UA and BA groups while intergroup comparison between UA and BA was non-significant (P > 0.05). Pain and discomfort, bleeding episode, ease of suctioning through nasal airway, pain and bleeding during removal of nasal airway (P < 0.0001) as well as surgeons and anaesthesiologists satisfaction criteria showed significant results among the NP group as compared to UA and BA groups (P < 0.05).
The present intervention to maintain airway patency can be termed as excellent with additional benefits like ease of suctioning; oxygen supplementation and a possible haemostatic effect due to pressure on the operated site. The low cost of the modified nasal airway and easily replicable design were the standout observations of the present study.
PMCID: PMC4173487
Airway obstruction; airway patency; fess; nasal airway; nasal packing
9.  Comparison of the effects of continuous positive airway pressure, oral appliance and exercise training in obstructive sleep apnea syndrome 
Clinics  2013;68(8):1168-1174.
There are several treatments for obstructive sleep apnea syndrome, such as weight loss, use of an oral appliance and continuous positive airway pressure, that can be used to reduce the signs and symptoms of obstructive sleep apnea syndrome. Few studies have evaluated the effectiveness of a physical training program compared with other treatments. The aim of this study was to assess the effects of physical exercise on subjective and objective sleep parameters, quality of life and mood in obstructive sleep apnea patients and to compare these effects with the effects of continuous positive airway pressure and oral appliance treatments.
Male patients with moderate to severe obstructive sleep apnea and body mass indices less than 30 kg/m2 were randomly assigned to three groups: continuous positive airway pressure (n = 9), oral appliance (n = 9) and physical exercise (n = 7). Polysomnographic recordings, blood samples and daytime sleepiness measurements were obtained prior to and after two months of physical exercise or treatment with continuous positive airway pressure or an oral appliance. NCT01289392
After treatment with continuous positive airway pressure or an oral appliance, the patients presented with a significant reduction in the apnea-hypopnea index. We did not observe changes in the sleep parameters studied in the physical exercise group. However, this group presented reductions in the following parameters: T leukocytes, very-low-density lipoprotein and triglycerides. Two months of exercise training also had a positive impact on subjective daytime sleepiness.
Our results suggest that isolated physical exercise training was able to modify only subjective daytime sleepiness and some blood measures. Continuous positive airway pressure and oral appliances modified the apnea-hypopnea index.
PMCID: PMC3752627  PMID: 24037015
Obstructive Sleep Apnea; CPAP; OA; Exercise Training; Subjective Daytime Sleepiness; Polysomnography
10.  Comparison of Size 2.5 i-gel™ with Proseal LMA™ in Anaesthetised, Paralyzed Children Undergoing Elective Surgery 
The newest variation of i-gel is its pediatric version. This novel supraglottic airway device has the added advantage of a drain tube. In this study, we compared the effectiveness of size 2.5 i-gel with size 2.5 ProSeal LMA.
This study was designed to investigate the usefulness of the size 2.5 i-gel compared with the ProSeal laryngeal mask airway (PLMA) of the same size in anesthetized, paralyzed children.
Materials and Methods:
Sixty ASA grade I – II patients undergoing elective surgery were included in this prospective study and were randomly assigned to the i-gel and PLMA groups (30 patients in each group). A size 2.5 supraglottic airway was inserted according to the assigned group. We assessed the ease of insertion, hemodynamic data, oropharyngeal sealing pressure, and postoperative complications.
There were no differences in the demographic and hemodynamic data, success rates for the first attempt of insertion, or postoperative airway morbidity among the two groups. The airway leak pressure of the i-gel group (27.12 ± 1.69 cm H2O) was significantly higher than that of the PLMA group (22.75 ± 1.46 cm H2O).
Hemodynamic parameters, ease of insertion and postoperative complications were comparable between the i-gel and PLMA, but the nairway sealing pressure was significantly higher in the i-gel group.
PMCID: PMC3482775  PMID: 23112965
I-gel; Pediatric patients; ProSeal laryngeal mask airway
11.  Randomized comparison of the i-gel™, the LMA Supreme™, and the Laryngeal Tube Suction-D using clinical and fibreoptic assessments in elective patients 
BMC Anesthesiology  2012;12:18.
The i-gel™, LMA-Supreme (LMA-S) and Laryngeal Tube Suction-D (LTS-D) are single-use supraglottic airway devices with an inbuilt drainage channel. We compared them with regard to their position in situ as well as to clinical performance data during elective surgery.
Prospective, randomized, comparative study of three groups of 40 elective surgical patients each. Speed of insertion and success rates, leak pressures (LP) at different cuff pressures, dynamic airway compliance, and signs of postoperative airway morbidity were recorded. Fibreoptic evaluation was used to determine the devices’ position in situ.
Leak pressures were similar (i-gel™ 25.9, LMA-S 27.1, LTS-D 24.0 cmH2O; the latter two at 60 cmH2O cuff pressure) as were insertion times (i-gel™ 10, LMA-S 11, LTS-D 14 sec). LP of the LMA-S was higher than that of the LTS-D at lower cuff pressures (p <0.05). Insertion success rates differed significantly: i-gel™ 95%, LMA-S 95%, LTS-D 70% (p <0.05). The fibreoptically assessed position was more frequently suboptimal with the LTS-D but this was not associated with impaired ventilation. Dynamic airway compliance was highest with the i-gel™ and lowest with the LTS-D (p <0.05). Airway morbidity was more pronounced with the LTS-D (p <0.01).
All devices were suitable for ventilating the patients’ lungs during elective surgery.
Trial registration
German Clinical Trial Register DRKS00000760
PMCID: PMC3434115  PMID: 22871204
Laryngeal mask airway; Leak pressure; Laryngeal Tube
12.  Airway management in patients with maxillofacial trauma – A retrospective study of 177 cases 
Airway management in maxillofacial injuries presents with a unique set of problems. Compromised airway is still a challenge to the anesthesiologist in spite of all modalities available. Maxillofacial injuries are the result of high-velocity trauma arising from road traffic accidents, sport injuries, falls and gunshot wounds. Any flaw in airway management may lead to grave morbidity and mortality in prehospital or hospital settings and as well as for reconstruction of fractures subsequently.
One hundred and seventy-seven patients of maxillofacial injuries, operated over a period of one and half years during July 2008 to December 2009 in Al-Nahdha hospital were reviewed. All patients were reviewed in depth with age related type of injury, etiology and techniques of difficult airway management.
The major etiology of injuries were road traffic accidents (67%) followed by sport (15%) and fall (15%). Majority of patients were young in the age group of 11-30 years (71 %). Fracture mandible (53%) was the most common injury, followed by fracture maxilla (21%), fracture zygoma (19%) and pan-facial fractures (6%). Maxillofacial injuries compromise mask ventilation and difficult airway due to facial fractures, tissue edema and deranged anatomy. Shared airway with the surgeon needs special attention due to restrictions imposed during surgery. Several methods available for securing the airway, both decision-making and performance, are important in such circumstances. Airway secured by nasal intubation with direct visualization of vocal cords was the most common (57%), followed by oral intubation (17%). Other methods like tracheostomy and blind nasal intubation was avoided by fiberoptic bronchoscopic nasal intubation in 26% of patients.
The results of this study indicated that surgically securing the airway by tracheostomy should be revised compared to other available methods. In the era of rigid fixation of fractures and the possibility of leaving the patient without wiring an open mouth and alternative techniques like fiberoptic bronchoscopic intubation, it is unnecessary to carry out tracheostomy for securing the airway as frequently as in the past.
PMCID: PMC3101764  PMID: 21655009
Difficult airway; fiberoptic bronchoscopic intubation; maxillofacial injuries; tracheostomy
13.  To assess the efficacy of i-gel for ventilation, blind tracheal intubation and nasogastric tube insertion 
The i-gel is a novel supraglottic airway device with a soft and non-inflatable cuff. In our study we attempted to evaluate the performance of i-gel as a ventilatory device, as a conduit to blind tracheal intubation using conventional polyvinyl chloride tracheal tube and gastric tube insertion through it.
Materials and Methods:
A total of 180 patients of American Society of Anesthesiologist (ASA) physical status I/II undergoing elective surgery under general anesthesia were included in this study. After induction of anesthesia, i-gel was inserted and the following parameters were recorded: Time taken for successful i-gel insertion, airway leak pressures, ease of gastric tube insertion and laryngeal view using fiberscope. Following this blind tracheal intubation was attempted. First attempt and overall success rate in blind tracheal intubation and gastric tube insertion were evaluated and tracheal intubation time was measured. Also presence of any side effects or complication following removal was recorded.
We achieved a 100% success rate in insertion of i-gel and in 171 out of 180 patients; i-gel was inserted in the 1st attempt itself. We also were able to achieve an overall success rate for blind endotracheal intubation via i-gel in 78.33% cases, and successful gastric tube placement was possible in 92.22%. In our study we also achieved a leak pressure of 25.52 (±2.33) cm of H2O.
I-gel may be effectively used for ventilation, nasogastric tube insertion and as a conduit to blind endotracheal intubation with minimal complication and acceptable airway sealing pressures.
PMCID: PMC4173497
I-gel; nasogastric tube; seal pressure; tracheal intubation
14.  Comparison of I-gel with proseal LMA in adult patients undergoing elective surgical procedures under general anesthesia without paralysis: A prospective randomized study 
We compared i-gel and ProSeal laryngeal mask airway (PLMA) regarding time taken for insertion, effective seal, fiberoptic view of larynx, ease of Ryle's tube insertion, and postoperative sore throat assessment.
Materials and Methods:
In a prospective, randomized manner, 48 adult patients of American Society of Anesthesiologists I-II of either gender between 18 and 60 years presenting for a short surgical procedure were assigned to undergo surgery under general anesthesia on spontaneous ventilation using either the i-gel or PLMA. An experienced nonblinded anesthesiologist inserted appropriate sized i-gel or PLMA in patients using standard insertion technique and assessed the intraoperative findings of the study regarding regarding time taken for respective device insertion, effective seal, fiberoptic view of larynx, ease of Ryle's tube insertion, and postoperative sore throat assessment. Postoperative assessment of sore throat was done by blinded anesthesia resident.
The time required for insertion of i-gel was lesser (21.98 ± 5.42 and 30.60 ± 8.51 s in Group I and Group P, respectively; P = 0.001). Numbers of attempts for successful insertions were comparable and in majority, device was inserted in first attempt. The mean airway leak pressures were comparable. However, there were more number of patients in Group P who had airway leak pressure >20 cm H2O. The fiberoptic view of glottis, ease of Ryle's tube insertion, and incidence of complications were comparable.
Time required for successful insertion of i-gel was less in adult patients undergoing short surgical procedure under general anesthesia on spontaneous ventilation. Patients with airway leak pressure >20 cm H2O were more in PLMA group which indicates its better suitability for controlled ventilation.
PMCID: PMC4009636  PMID: 24803754
Airway leak pressure; i-gel; PLMA; time for insertion
15.  Innovative treatments for adults with obstructive sleep apnea 
Nature and Science of Sleep  2014;6:137-147.
Obstructive sleep apnea (OSA) affects one in five adult males and is associated with significant comorbidity, cognitive impairment, excessive daytime sleepiness, and reduced quality of life. For over 25 years, the primary treatment has been continuous positive airway pressure, which introduces a column of air that serves as a pneumatic splint for the upper airway, preventing the airway collapse that is the physiologic definition of this syndrome. However, issues with patient tolerance and unacceptable levels of treatment adherence motivated the exploration of other potential treatments. With greater understanding of the physiologic mechanisms associated with OSA, novel interventions have emerged in the last 5 years. The purpose of this article is to describe new treatments for OSA and associated complex sleep apnea. New approaches to complex sleep apnea have included adaptive servoventilation. There is increased literature on the contribution of behavioral interventions to improve adherence with continuous positive airway pressure that have proven quite effective. New non-surgical treatments include oral pressure devices, improved mandibular advancement devices, nasal expiratory positive airway pressure, and newer approaches to positional therapy. Recent innovations in surgical interventions have included laser-assisted uvulopalatoplasty, radiofrequency ablation, palatal implants, and electrical stimulation of the upper airway muscles. No drugs have been approved to treat OSA, but potential drug therapies have centered on increasing ventilatory drive, altering the arousal threshold, modifying loop gain (a dimensionless value quantifying the stability of the ventilatory control system), or preventing airway collapse by affecting the surface tension. An emerging approach is the application of cannabinoids to increase upper airway tone.
PMCID: PMC4242689  PMID: 25429246
obstructive sleep apnea; innovative treatment; continuous positive airway pressure; oral appliance; nerve stimulation
16.  Survival after Lung Volume Reduction in Chronic Obstructive Pulmonary Disease 
Rationale: COPD is associated with reduced life expectancy.
Objectives: To determine the association between small airway pathology and long-term survival after lung volume reduction in chronic obstructive pulmonary disease (COPD) and the effect of corticosteroids on this pathology.
Methods: Patients with severe (GOLD-3) and very severe (GOLD-4) COPD (n = 101) were studied after lung volume reduction surgery. Respiratory symptoms, quality of life, pulmonary function, exercise tolerance, chest radiology, and corticosteroid treatment status were assessed preoperatively. The severity of luminal occlusion, wall thickening, and the presence of small airways containing lymphoid follicles were determined in resected lung tissue. Kaplan-Meier survival analysis and Cox proportional hazards models were used to determine the relationship between survival and small airway pathology. The effect of corticosteroids on this pathology was assessed by comparing treated and untreated groups.
Measurements and Main Results: The quartile of subjects with the greatest luminal occlusion, adjusted for covariates, died earlier than subjects who had the least occlusion (hazard ratio, 3.28; 95% confidence interval, 1.55–6.92; P = 0.002). There was a trend toward a reduction in the number of airways containing lymphoid follicles (P = 0.051) in those receiving corticosteroids, with a statistically significant difference between the control and oral ± inhaled corticosteroid–treated groups (P = 0.019). However, corticosteroid treatment had no effect on airway wall thickening or luminal occlusion.
Conclusions: Occlusion of the small airways by inflammatory exudates containing mucus is associated with early death in patients with severe emphysema treated by lung volume reduction surgery. Corticosteroid treatment dampens the host immune response in these airways by reducing lymphoid follicles without changing wall thickening and luminal occlusion.
PMCID: PMC1976540  PMID: 17556723
premature death in COPD; airway remodeling; mucosal immune response; corticosteroids
17.  Simultaneous sleep study and nasoendoscopic investigation in a patient with obstructive sleep apnoea syndrome refractory to continuous positive airway pressure: a case report 
The standard treatment for obstructive sleep apnoea syndrome is nasal continuous positive airway pressure. In most cases the obstruction is located at the oropharyngeal level, and nasal continuous positive airway pressure is usually effective. In cases of non-response to nasal continuous positive airway pressure other treatments like mandibular advancement devices or upper airway surgery (especially bi-maxillary advancement) may also be considered.
Case presentation
We report the case of a 38-year-old Caucasian man with severe obstructive sleep apnoea syndrome, initially refractory to nasal continuous positive airway pressure (and subsequently also to a mandibular advancement devices), in which the visualization of the upper airway with sleep endoscopy and the concomitant titration of positive pressure were useful in the investigation and resolution of sleep disordered breathing. In fact, there was a marked reduction in the size of his nasopharynx, and a paresis of his left aryepiglotic fold with hypertrophy of the right aryepiglotic fold. The application of bi-level positive airway pressure and an oral interface successfully managed his obstructive sleep apnoea.
This is a rare case of obstructive sleep apnoea syndrome refractory to treatment with nocturnal ventilatory support. Visualization of the endoscopic changes, during sleep and under positive pressure, was of great value to understanding the mechanisms of refractoriness. It also oriented the therapeutic option. Refractoriness to obstructive sleep apnoea therapy with continuous positive airway pressure is rare, and each case should be approached individually.
PMCID: PMC2803838  PMID: 20062744
18.  Midline Submental Orotracheal Intubation in Maxillofacial Injuries: A Substitute to Tracheostomy Where Postoperative Mechanical Ventilation is not Required 
Maxillofacial fractures present unique airway problems to the anaesthesiologist. Nasotracheal intubation is contraindicated due to associated Lefort I, II or III fractures. The requirement for intraoperative maxillomandibular fixation (MMF) to re-establish dental occlusion in such cases precludes orotracheal intubation. Tracheostomy has a high complication rate and in many patients, an alternative to the oral airway is not required beyond the perioperative period. Hernandez1 in 1986 first described “The submental route for endotracheal intubation”. Later some workers faced difficult tube passage, bleeding, and sublingual gland involvement with this approach. They modified this to strict midline submental intubation and there were no operative or postoperative complications in their cases.67&8. Therefore we used mid line approach for submental orotracheal intubation in this study to demonstrate its feasibility and reliability and that it can be used as an excellent substitute to short term tracheostomy.
Patients & Methods:
We used midline submental intubation in 25 cases selected out of 310 consecutively treated patients with maxillofacial trauma over a 3 year period. After induction orotracheal intubation was done with spiral re-inforced tube. A 1.5-2.0 cm skin incision was made in the submental region in the midline 2.0 cm behind the symphysis and endotracheal tube was taken out through this incision in all the cases. At the end of the surgery the procedure was reversed, the submental wound was stitched; all the patients could be extubated & none of them required post-operative mechanical ventilation.
There were no significant operative or postoperative complications. Postoperative submental scarring was acceptable[6]. We conclude that midline submental intubation is a simple and useful technique with low morbidity. It can be chosen in selected cases of maxillofacial trauma and is an excellent substitute to tracheostomy where postoperative mechanical ventilation is not required.
PMCID: PMC3087271  PMID: 21547178
Submental orotracheal intubation; Maxillofacial injury; Tracheostomy
19.  Psychological implications in ENT diseases 
We are sometimes faced with psychic derangement or overlay in some of the ENT diseases and the link between patient’s psyche and any ENT disease at times becomes signifi cant and troublesome. The conditions in the fi eld between otorhinolaryngology and psychiatry can be classifi ed as psychiatric symptoms resulting from ENT diseases or interventions and those expressing themselves as ENT symptoms due to mental ailment. The former include hearing impairment, dizziness, tinnitus, choked airway, bad oral breath, stuffy nose, traumatic interventions and external nasal deformities. The later include exaggerated and diminished pharyngeal refl ex, globus hystericus, speech disorders, vasomotor rhinitis, nose picking, choked feeling, dizziness and headache. At times diseases originate in the human mind (consciousness), causing negative thoughts like jealousy, anger, and depression due to frustration. p ]A healthy mind in a healthy body generates sound and noble thoughts. Once a healthy body-mind relationship is established, we can be reasonably sure that greater happiness and success is within our reach. Patient seeking help from ENT surgeons to change their physical appearances and or function may not understand that the ultimate goal of surgery is to bring about psychological change by modifying the physical change, which is important aspect in septorhinoplastic surgery. At times patients asking for corrective rhinoplasty for minor external nasal deformities may have underlying psychological disturbance and use even slight external nasal deformity as scapegoat for psychological upset. Males are more diffi cult patients psychologically for any facial cosmetic surgery. These days some patients read about their diseases or treatment on the Internet and get more confused and psychologically disturbed due to rare causes of their illness, rare complications and diversity of treatment available.
PMCID: PMC3449991  PMID: 23120613
Psychological disorders; Rhinoplasty; Otorhinolaryngology; Placebo
20.  Multiscale image-based modeling and simulation of gas flow and particle transport in the human lungs 
Improved understanding of structure and function relationships in the human lungs in individuals and sub-populations is fundamentally important to the future of pulmonary medicine. Image-based measures of the lungs can provide sensitive indicators of localized features, however to provide a better prediction of lung response to disease, treatment and environment, it is desirable to integrate quantifiable regional features from imaging with associated value-added high-level modeling. With this objective in mind, recent advances in computational fluid dynamics (CFD) of the bronchial airways - from a single bifurcation symmetric model to a multiscale image-based subject-specific lung model - will be reviewed. The interaction of CFD models with local parenchymal tissue expansion - assessed by image registration - allows new understanding of the interplay between environment, hot spots where inhaled aerosols could accumulate, and inflammation. To bridge ventilation function with image-derived central airway structure in CFD, an airway geometrical modeling method that spans from the model ‘entrance’ to the terminal bronchioles will be introduced. Finally, the effects of turbulent flows and CFD turbulence models on aerosol transport and deposition will be discussed.
CFD simulation of airflow and particle transport in the human lung has been pursued by a number of research groups, whose interest has been in studying flow physics and airways resistance, improving drug delivery, or investigating which populations are most susceptible to inhaled pollutants. The three most important factors that need to be considered in airway CFD studies are lung structure, regional lung function, and flow characteristics. Their correct treatment is important because the transport of therapeutic or pollutant particles is dependent on the characteristics of the flow by which they are transported; and the airflow in the lungs is dependent on the geometry of the airways and how ventilation is distributed to the peripheral tissue. The human airway structure spans more than 20 generations, beginning with the extra-thoracic airways (oral or nasal cavity, and through the pharynx and larynx to the trachea), then the conducting airways, the respiratory airways, and to the alveoli. The airways in individuals and sub-populations (by gender, age, ethnicity, and normal vs. diseased states) may exhibit different dimensions, branching patterns and angles, and thickness and rigidity. At the local level, one would like to capture detailed flow characteristics, e.g. local velocity profiles, shear stress, and pressure, for prediction of particle transport in an airway (lung structure) model that is specific to the geometry of an individual, to understand how inter-subject variation in airway geometry (normal or pathological) influences the transport and deposition of particles. In a systems biology – or multiscale modeling – approach, these local flow characteristics can be further integrated with epithelial cell models for the study of mechanotransduction. At the global (organ) level, one would like to match regional ventilation (lung function) that is specific to the individual, thus ensuring that the flow that transports inhaled particles is appropriately distributed throughout the lung model. Computational models that do not account for realistic distribution of ventilation are not capable of predicting realistic particle distribution or targeted drug deposition. Furthermore, the flow in the human lung can be transitional or turbulent in the upper and proximal airways, and becomes laminar in the distal airways. The flows in the laminar, transitional and turbulent regimes have different temporal and spatial scales. Therefore, modeling airway structure and predicting gas flow and particle transport at both local and global levels require image-guided multiscale modeling strategies.
In this article, we will review the aforementioned three key aspects of CFD studies of the human lungs: airway structure (conducting airways), lung function (regional ventilation and boundary conditions), and flow characteristics (modeling of turbulent flow and its effect on particle transport). For modeling airway structure, we will focus on the conducting airways, and review both symmetric vs. asymmetric airway models, idealized vs. CT-based airway models, and multiscale subject-specific airway models. Imposition of physiological subject-specific boundary conditions (BCs) in CFD is essential to match regional ventilation in individuals, which is also critical in studying preferential deposition of inhaled aerosols in sub-populations, e.g. normals vs. asthmatics that may exhibit different ventilation patterns. Subject-specific regional ventilation defines flow distributions and characteristics in airway segments and bifurcations, which subsequently determines the transport and deposition of aerosols in the entire lungs. Turbulence models are needed to capture the transient and turbulent nature of the gas flow in the human lungs. Thus, the advantages and disadvantages of different turbulence models as well as their effects on particle transport will be discussed. The ultimate goal of the development is to identify sensitive structural and functional variables in sub-populations of normal and diseased lungs for potential clinical applications.
PMCID: PMC3763693  PMID: 23843310
21.  Comparison of the Proseal LMA and intersurgical I-gel during gynecological laparoscopy 
Korean Journal of Anesthesiology  2012;63(6):510-514.
The relatively recently developed I-gel (Intersurgical Ltd., Workingham, England) is a supraglottic airway device designed for single-use that, unlike conventional LMAs, does not require an inflatable cuff. In addition, the I-gel, much like the Proseal LMA (PLMA), has a gastric drainage tube associated with an upper tube for decompression of the stomach, thereby avoiding acid reflux and decreasing the risk of pulmonary absorption. The purpose of this study was to compare PLMA and I-gel devices in patients undergoing gynecological laparoscopy based on sealing pressure before and during pneumoperitoneum, insertion time, and gas exchange.
Following Institutional Review Board approval and written informed consent, 30 adult patients were randomly allocated to one of two groups (the PLMA or I-gel group). In each case, insertion time and number of attempts were recorded. After successful insertion, airway leak pressure was measured.
Successful insertion and mechanical ventilation with both supraglottic airway devices was achieved on the first attempt in all 30 patients, and there were no significant differences with respect to insertion time. Likewise, leak pressure did not vary significantly either between or within groups after CO2 insufflation. In addition, differences between leak volume and leak fraction between groups were not significant.
The results of our study indicate that the I-gel is a reasonable alternative to the PLMA for controlled ventilation during laparoscopic gynecologic surgery.
PMCID: PMC3531529  PMID: 23277811
I-gel; PLMA
22.  Review of oral appliances for treatment of sleep-disordered breathing 
Between 1982 and 2006, there were 89 distinct publications dealing with oral appliance therapy involving a total of 3,027 patients, which reported results of sleep studies performed with and without the appliance. These studies, which constitute a very heterogeneous group in terms of methodology and patient population, are reviewed and the results summarized. This review focused on the following outcomes: sleep apnea (i.e. reduction in the apnea/hypopnea index or respiratory disturbance index), ability of oral appliances to reduce snoring, effect of oral appliances on daytime function, comparison of oral appliances with other treatments (continuous positive airway pressure and surgery), side effects, dental changes (overbite and overjet), and long-term compliance. We found that the success rate, defined as the ability of the oral appliances to reduce apnea/hypopnea index to less than 10, is 54%. The response rate, defined as at least 50% reduction in the initial apnea/hypopnea index (although it still remained above 10), is 21%. When only the results of randomized, crossover, placebo-controlled studies are considered, the success and response rates are 50% and 14%, respectively. Snoring was reduced by 45%. In the studies comparing oral appliances to continuous positive airway pressure (CPAP) or to uvulopalatopharyngoplasty (UPPP), an appliance reduced initial AHI by 42%, CPAP reduced it by 75%, and UPPP by 30%. The majority of patients prefer using oral appliance than CPAP. Use of oral appliances improves daytime function somewhat; the Epworth sleepiness score (ESS) dropped from 11.2 to 7.8 in 854 patients. A summary of the follow-up compliance data shows that at 30 months, 56–68% of patients continue to use oral appliance. Side effects are relatively minor but frequent. The most common ones are excessive salivation and teeth discomfort. Efficacy and side effects depend on the type of appliance, degree of protrusion, vertical opening, and other settings. We conclude that oral appliances, although not as effective as CPAP in reducing sleep apnea, snoring, and improving daytime function, have a definite role in the treatment of snoring and sleep apnea.
PMCID: PMC1794626  PMID: 17136406
Continuous positive airway pressure; Sleep apnea; Oral appliance
23.  Randomized crossover comparison of the laryngeal mask airway classic with i-gel laryngeal mask airway in the management of difficult airway in post burn neck contracture patients 
Indian Journal of Anaesthesia  2012;56(4):348-352.
The objective of the study was to compare the performance of i-gel supraglottic airway with cLMA in difficult airway management in post burn neck contracture patients and assess the feasibility of i-gel use for emergency airway management in difficult airway situation with reduced neck movement and limited mouth opening.
Prospective, crossover, randomized controlled trial was performed amongst forty eight post burn neck contracture patients with limited mouth opening and neck movement. i-gel and cLMA were placed in random order in each patient. Primary outcome was overall success rate. Other measurements were time to successful ventilation, airway leak pressure, fiberoptic glottic view, visualization of square wave pattern.
Success rate for the i-gel was 91.7% versus 79.2% for the cLMA. i-gel required shorter insertion time (19.3 seconds vs. 23.5 seconds, P=0.000). Airway leak pressure difference was statistically significant (i-gel 21.2 cm H20; cLMA 16.9 cm H20; P=0.00). Fiberoptic view through the i-gel showed there were less epiglottic downfolding and better fiberoptic view of the glottis than cLMA. Overall agreement in insertion outcome for i-gel was 22/24 (91.7%) successes and 2/24(8.3%) failure and for cLMA, 19/24 (79.16%) successes and 5/24 (16.7%) failure in the first attempt.
The i-gel is cheap, effective airway device which is easier to insert and has better clinical performance in the difficult airway management of the airway in the post burn contracture of the neck. Our study shows that i-gel is feasible for emergency airway management in difficult airway situation with reduced neck movement and limited mouth opening in post burn neck.
PMCID: PMC3469912  PMID: 23087456
cLMA; difficult airway management; i-gel; post burn neck contracture
24.  The role of the nose in snoring and obstructive sleep apnoea: an update 
Multilevel anatomic obstruction is often present in snoring and obstructive sleep apnoea (OSA). As the nose is the first anatomical boundary of the upper airway, nasal obstruction may contribute to sleep-disordered breathing (SDB). A number of pathophysiological mechanisms can potentially explain the role of nasal pathology in SDB. These include the Starling resistor model, the unstable oral airway, the nasal ventilatory reflex and the role of nitric oxide (NO). Clinically, a number of case–control studies have shown that nasal obstruction is associated with snoring and mild SDB. However, there is not a linear correlation between the degree of nasal obstruction and the severity of SDB, while nasal obstruction is not the main contributing factor in the majority of patients with moderate to severe OSA. Randomised controlled studies have shown that in patients with allergic rhinitis or non-allergic rhinitis and sleep disturbance, nasal steroids could improve the subjective quality of sleep, and may be useful for patients with mild OSA, however, they are not by themselves an adequate treatment for most OSA patients. Similarly, nasal surgery may improve quality of life and snoring in a subgroup of patients with mild SDB and septal deviation, but it is not an effective treatment for OSA as such. On the other hand, in patients who do not tolerate continuous positive airway pressure (CPAP) well, if upper airway evaluation demonstrates an obstructive nasal passage, nasal airway surgery can improve CPAP compliance and adherence.
PMCID: PMC3149667  PMID: 21340561
Sleep-disordered breathing; Obstructive sleep apnoea; Nasal disease; Rhinitis; Chronic rhinosinusitis; Nasal septum deviation; CPAP
25.  Improvements in current treatments and emerging therapies for adult obstructive sleep apnea 
F1000Prime Reports  2014;6:36.
Obstructive sleep apnea (OSA) is common and is associated with a number of adverse outcomes, including an increased risk for cardiovascular disease. Typical treatment approaches, including positive airway pressure, oral appliances, various upper airway surgeries, and/or weight loss, can improve symptoms and reduce the severity of disease in select patient groups. However, these approaches have several potential limitations, including suboptimal adherence, lack of suitability for all patient groups, and/or absence of adequate outcomes data. Emerging potential therapeutic options, including nasal expiratory positive airway pressure (PAP), oral negative pressure, upper airway muscle stimulation, and bariatric surgery, as well as improvements in existing treatments and the utilization of improving technologies are moving the field forward and should offer effective therapies to a wider group of patients with OSA.
PMCID: PMC4017906  PMID: 24860658

Results 1-25 (202825)