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We describe pharyngeal oximetry with the laryngeal mask airway in two patients with low perfusion states where finger oximetry failed.One patient was a 47-yr-old man with septic shock and the other a 64-yr-old man with multiorgan failure. In both patients, a # 4 laryngeal mask airway with a pediatric pulse oximeter probe was inserted behind the tracheal tube. A good waveform was obtained and oxygen saturation was 0-2% lower than arterial samples.Pharyngeal oximetry with the laryngeal mask airway is feasible in low perfusion states when finger oximetry fails.

We conducted three studies to test the hypothesis that elevation of the intubating laryngeal mask (ILM) handle increases efficacy of seal, changes fibreoptic position, prevents aspiration of regurgitated fluid and improves intubation. In study 1, the ILM was inserted into 20 paralysed, anaesthetized patients and 20 cadavers. Oropharyngeal leak pressure and fibreoptic position were measured at an intracuff pressure of 0, 60 and 120 cm H 2 O with 0, 20 and 40 N of elevation force. In study 2, the oesophageal pressure at which regurgitation and aspiration occurred was measured in 20 cadavers with the ILM at the above intracuff pressures and elevation forces and 10 cadavers without the ILM (controls). In study 3, ease of blind intubation (first attempt only) was determined in 20 paralysed, anaesthetized patients at 0 and 40 N elevation force. In study 1, there was a significant increase in oropharyngeal leak pressure with increasing elevation force at an intracuff pressure of 0 and 60 cm H 2 O. There were no changes in fibreoptic position. Oropharyngeal leak pressure and fibreoptic position were similar between patients and cadavers. In study 2, oesophageal pressure for regurgitation and aspiration was usually greater for the ILM than controls (all: P

We quantified the extent and distribution of segmental cervical movement produced by the intubating laryngeal mask (ILM) during manual in-line stabilization in 20 anesthetized patients with cervical pathology undergoing cervical spine surgery. All patients had neurological symptoms preoperatively. The ILM was inserted with the head and neck in the neutral position. Intubation was facilitated by transillumination of the neck with a lightwand. Cervical movement was recorded with single-frame lateral radiographic images taken 1) immediately before induction (baseline); 2) during ILM insertion (insertion); 3) when transillumination was first seen at the cricothyroid membrane (intubation A); 4) when the tube was being advanced into the trachea (intubation B); and 5) during ILM removal (removal). Radiographic images were digitized and the degree of flexion/extension and posterior movement measured for the occiput (C0) through to C5. During ILM insertion, C0-5 were flexed by an average of 1-1.6 degrees (all P0.05). During intubation A/B, C0-4 were flexed by an average of 1.4-3.0 degrees (all P0.01), but C5 was unchanged. During ILM removal, C0-3 were flexed by an average of 1 degree (all: P0.05), but C3-5 were unchanged. During insertion and intubation A/B, C2-5 were displaced posteriorly by an average of 0.5-1.0 mm (all: P0.05). During removal, there was no change at C1-5. Neurological symptoms improved in all patients. We conclude that the ILM produces segmental movement of the cervical spine despite manual in-line stabilization in patients with cervical spine pathology undergoing cervical spine surgery. This motion is in the opposite direction to direct laryngoscopy, suggesting that different approaches to airway management may be more appropriate depending on the nature of the cervical instability.The intubating laryngeal mask produces segmental movement of the cervical spine, despite manual in-line stabilization in patients with cervical spine pathology undergoing cervical spine surgery. This motion is in the opposite direction to direct laryngoscopy, suggesting that different approaches to airway management may be more appropriate depending on the nature of the cervical instability.

We tested the hypothesis that haemodynamic changes to intubation and postoperative pharyngolaryngeal morbidity are similar for blind intubating laryngeal mask (ILM)-guided compared with laryngoscope-guided tracheal intubation in adults with normal airways. We also compared intubation success rates and airway complications. One-hundred and fifty paralysed, anaesthetized adult patients undergoing elective surgery were randomly assigned to one of three equal-sized groups: 1. blind intubation via the ILM using a straight, silicone tube; 2. intubation with a Macintosh laryngoscope using a straight silicone tube and 3. intubation with a Macintosh laryngoscope using a polyvinyl chloride tube (controls). A standard sequence of adjusting manoeuvres was followed if intubation was difficult. The number of adjusting manoeuvres and intubation attempts, time to intubation, intubation success rate (first attempt and within 3 min), haemodynamic changes (pre-induction, post-induction, post-intubation), oesophageal intubation, mucosal trauma (blood detected), hypoxia (SpO2

We measured directly mucosal pressures against the cuff and non-cuff portions of the tracheal tube in different head-neck positions and tested the reliability of calculated mucosal pressures, in vivo intracuff pressures and cuff volume as determinants of directly measured mucosal pressures. We studied 10 anaesthetized, paralysed adult patients. An 8.5-mm, high volume, low pressure PVC tracheal tube was used. Microchip sensors were attached to three cuff locations (anterior, lateral and posterior) and two non-cuff locations (anterior tip and anterior aspect of the tube, 5 cm proximal to the cuff). Directly measured mucosal pressures, in vivo intracuff pressures and calculated mucosal pressures (in vivo minus in vitro intracuff pressures) were determined after brief inflation (< 15 s) to 0, 5, 10 and 15 ml. In vivo intracuff pressures were then set at 30 mm Hg and the measurements repeated, first in the neutral position and then with the head-neck extended, flexed and rotated. Cuff mucosal pressures were highest anteriorly and lowest posteriorly. Non-cuff mucosal pressures did not vary with cuff volume and were approximately 15 mm Hg. Compared with the neutral position, in vivo intracuff pressures were higher in the rotated, extended and flexed positions. Compared with the neutral position, mucosal pressure increased on the anterior aspect of the tube in the flexed position by 22 mm Hg (P = 0.003), at the anterior tip in the extended position by 11 mm Hg (P = 0.002) and at the anterior tip (5 mm Hg, P = 0.05) and lateral aspect of the cuff (5 mm Hg, P = 0.03) in the rotated position. In vivo intracuff pressures and calculated mucosal pressures were moderate predictors of measured mucosal pressures; cuff volume was a poor predictor. We conclude that tracheal mucosal pressures were highest anteriorly, that non-cuff portions of the tube exerted substantial mucosal pressures and that the rotated position caused a greater increase in tracheal mucosal pressure than the extended or flexed position. Indirect methods of measuring mucosal pressure were of moderate predictive value.

We have compared calculated with measured pharyngeal mucosal pressures at four different locations on the surface of the laryngeal mask airway (LMA) during cuff inflation in 10 anaesthetized, paralysed adult patients. Microchip sensors were attached to a size 5 LMA at the following locations: the anterior and lateral side, tip and backplate. Pressures were recorded during inflation of the cuff from 0 to 40 ml in 5-ml increments. Calculated pressures were determined by subtracting in vivo from in vitro intracuff pressures. Calculated pressures were greater than measured pressures at cuff volumes of 5 ml or greater at all locations (Por = 0.003). The greatest mean calculated the measured pressures were 118 and 14 cm H2O, respectively. We conclude that measured mucosal pressures at the four locations tested were less than calculated pressures and less than capillary perfusion pressure.

We have compared the liability of four laryngeal mask airway (LMA) devices (standard, flexible, intubating and reusable) and a tracheal tube to thermal damage from KTP and Nd:YAG lasers at two power densities used commonly in airway surgery: 570 W cm-2 and 1140 W cm-2. Eighty-five airway devices were tested: 24 standard LMA (silicone-based), 12 flexible LMA (silicone-based, metal wires), 24 disposable LMA (PVC-based), one intubating LMA (silicone and steel-based) and 24 PVC-based tracheal tubes. Comparisons were made during laser strike to eight different targets: the unmarked and marked part of the airway device tube; the unmarked part of the airway device tube after application of blood; the cuff filled with air or methylene blue dye; the unmarked flexible LMA tube on or between the metal wires; and the epiglottic elevator bar of the intubating LMA. The laser strike was continued for 30 s and each target was tested three times. Three different, but identical, impact sites were used for each target. There was no ignition of any airway device with either power density or laser type. The silicone-based LMA were generally more resistant to flaring and penetration than the PVC-based LMA and tracheal tube, but the intubating LMA tube flared more rapidly with the KTP laser, and the disposable LMA cuff was more resistant to penetration. Print markings, blood and the metal wires of the flexible LMA reduced the thermal resistance of the tube. Filling the cuff with methylene blue dye increased the thermal resistance of all airway devices. We conclude that the silicone-based LMA devices were more thermal resistant to KTP and Nd:YAG laser strike than PVC-based devices with the exception of the disposable LMA cuff and the intubating LMA tube.

We report the successful use of the intubating laryngeal mask airway in a patient with maxillo-facial trauma for whom the facemask and laryngoscope were relatively contraindicated and the fibreoptic scope potentially difficult to use.

Background The tube of the intubating laryngeal mask (ILM) is more rigid than the standard laryngeal mask airway (LMA), and the authors have tested the hypothesis that pharyngeal mucosal pressures, airway sealing pressures, and fiberoptic position are different when the two devices are compared. Methods Twenty anesthetized, paralyzed adults were randomly allocated to receive either the LMA or ILM for airway management. Microchip sensors were attached to the size 5 LMA or ILM at locations corresponding to the pyriform fossa, hypopharynx, base of tongue, posterior pharynx, and distal and proximal oropharynx. Mucosal pressures, airway sealing pressures, and fiberoptic positioning were recorded during inflation of the cuff from 0 to 40 ml in 10-ml increments. Results Airway sealing pressures were higher for the ILM (30 vs. 23 cm H2O), but epiglottic downfolding was more common (56% vs. 26%). Pharyngeal mucosal pressures were much higher for the ILM at five of six locations. Mean mucosal pressures in the distal oropharynx for the ILM were always greater than 157 cm H2O, regardless of cuff volume. There was no correlation between mucosal pressures and airway sealing pressures at any location for the LMA, but there was a correlation at three of six locations for the ILM. Conclusions The ILM provides a more effective seal than the LMA, but pharyngeal mucosal pressures are higher and always exceed capillary perfusion pressure. The ILM is unsuitable for use as a routine airway and should be removed after its use as an airway intubator.

Background The hypothesis that airway resistance is less with the laryngeal mask airway than with the endotracheal tube was tested. Methods Thirty-six paralyzed, anesthetized adult patients with no respiratory disease (American Society of Anesthesiologists physical status 1-3; age, 18-80 yr) were randomly allocated (9 men, 9 women in each group) to receive either a size-4 laryngeal mask airway or an endotracheal tube (men, 9-mm ID; women, 8-mm ID). A pulmonary monitor with flow transducer and esophageal balloon was used to measure peak airway pressure and mean airway resistance (device resistance plus pulmonary airway resistance) at three different tidal volumes (5, 10, and 15 ml/kg). Device resistance was measured in vitro with the distal end of the endotracheal tube or laryngeal mask airway open to the atmosphere and using the same ventilator settings. Pulmonary airway resistance was derived by subtracting the mean device resistance from the mean airway resistance. Results Peak airway pressure, mean airway resistance, device resistance, and pulmonary airway resistance were greater for the endotracheal tube (all P < 0.0001). Conclusions The laryngeal mask airway triggers less bronchoconstriction than does the endotracheal tube in paralyzed anesthetized adult patients. This may have implications for maintaining intraoperative pulmonary function and reducing the risk for atelectasis and pulmonary infection.

We have studied the incidence of gastro-oesophageal reflux associated with the laryngeal mask airway (LMA) in 82 paralysed patients undergoing ventilation for elective orthopaedic surgery. Anaesthesia was managed by skilled LMA users. A pH-sensitive probe was passed nasally into the oesophagus before induction and recordings made during five phases of anaesthesia. Anaesthesia was induced with propofol and fentanyl and maintained with 0.5-1.5% isoflurane and nitrous oxide in oxygen. Neuromuscular block was produced with vecuronium and the train-of-four count maintained ator = 1. Towards the end of surgery, neuromuscular function was allowed to recover spontaneously. All LMAs were inserted at the first attempt and ventilation was successful in all patients. There were no adverse airway events. Mean oesophageal pH values during each phase of anaesthesia were: before insertion 5.88 (SD 0.77), placement 5.85 (0.74), maintenance 5.89 (0.73), emergence 5.71 (0.78) and removal 5.82 (0.75). There were no reflux events (pH4.0) during any phase of anaesthesia. We conclude that the incidence of gastro-oesophageal reflux is low in paralysed patients undergoing ventilation for elective orthopaedic surgery when antagonism of neuromuscular block is avoided. The validity of these findings for unskilled LMA users is unknown.

We measured pharyngeal mucosal pressures at six different locations on the laryngeal mask airway (LMA) and tested the hypothesis that the efficacy of the seal is not related to pharyngeal mucosal pressure. Twenty anesthetized, paralyzed adult patients were studied. Microchip sensors were attached to the size 5 LMA at locations corresponding to the lateral and posterior pharynx, the hypopharynx, the pyriform fossa, the base of tongue, and the oropharynx. Mucosal pressures and airway sealing pressures were recorded during inflation of the cuff from 0 to 40 mL in 10-mL increments. The highest mean mucosal pressure was in the oropharynx (26 cm HO), and the lowest was in the posterior pharynx (2 cm HO). Mucosal pressures increased with increasing intracuff pressure and cuff volume, but the rate of increase varied among locations. Airway sealing pressure increased with increasing intracuff volume from 0 to 10 mL (P < 0.0001) and 10 to 20 mL (P = 0.0001), was unchanged from 20 to 30 mL, and decreased from 30 to 40 mL (P = 0.005). The airway sealing pressure was higher than pharyngeal mucosal pressure until the intracuff volume was ≥30 mL. There was no correlation between mucosal pressures and airway sealing pressure at any location. We conclude that the efficacy of the seal is not related to pharyngeal mucosal pressure. Pharyngeal mucosal pressures are generally lower than those considered safe for the tracheal mucosa during prolonged intubation. Implications: We measured pharyngeal mucosal pressures at six different locations on the laryngeal mask airway and showed that the efficacy of the seal is not related to pharyngeal mucosal pressure. Pharyngeal mucosal pressures are generally lower than those considered safe for the tracheal mucosa during prolonged intubation.

A disposable (polyvinyl chloride) laryngeal mask airway (LMA) with dimensions identical to, but physical properties different from (stiffer tube/thicker cuff), the reusable (silicone) LMA has recently become available. We performed a randomized, cross-over study of 60 paralyzed, anesthetized patients to test the hypothesis that the use of these devices was different in terms of ease of insertion, airway sealing pressure, fiberoptic position, and changes in intracuff pressure during NO anesthesia. We also tested the hypothesis that the airway sealing pressure of the LMA is suboptimal if the cuff is inflated to a high intracuff pressure. Both the devices were inserted into each patient in random order, and their performance was assessed at two intracuff pressures (60 and 180 cm HO) by a blind observer. Subsequently, intracuff pressures were measured during NO anesthesia for the second device. Ease of insertion was similar: there was no difference in first attempt success rates (97% vs 98%) and insertion times (15 vs 13 s) for the disposable and reusable LMA, respectively. There were no differences in airway sealing pressure or fiberoptic position. Airway sealing pressure was significantly higher at 60 cm HO intracuff pressure compared with the airway sealing pressure at 180 cm HO for both devices (P < 0.02). During NO anesthesia, the intracuff pressure remained stable for the disposable LMA but increased significantly for the reusable LMA We conclude that the disposable and reusable LMAs perform similarly in paralyZed adult patients, but that the disposable LMA has more stable intracuff pressures during NO anesthesia. Inflation of the LMA to high intracuff pressures produces a suboptimal seal. Implications: This randomized, single-blind, within-patient study of 60 adult patients shows that the disposable (polyvinyl chloride) and reusable (silicone) laryngeal mask airways perform similarly, but that the disposable laryngeal mask airway has more stable intracuff pressures during NO anesthesia. Inflation of either device to high intracuff pressures produces a suboptimal seal.

In assessing the potential role of the LMA outside the operating room, the risks of a less secure airway must be balanced against the benefits of ease of training, success and speed of insertion, no need for direct visualization of laryngeal structures, and lesser need for ancillary equipment. The LMA has a role as an alternative to FMV in CPR when personnel skilled in tracheal intubation are not available. When skilled intubators are present, it has an important role as an alternative airway when intubation has been impossible. These roles extend to the prehospital setting, with an additional specific indication for its use when access to a patient is limited making tracheal intubation impossible. The LMA is incorporated into advanced life support training and as such should be regarded as a device providing temporary airway support, rather than a replacement for a tracheal tube. The LMA, and possibly also the ILM, should be standard equipment carried by prehospital trauma teams and by all those attending victims in the field.

To compare patient outcomes for positive pressure ventilation (PPV) and spontaneous ventilation (SV) in non-paralysed patients with the LMA using either isoflurane or sevoflurane anaesthesia.One hundred and sixty four adult patients were studied. Anaesthesia was with fentanyl/propofol and N2O 66% in O2 with 0.75 MAC isoflurane or sevoflurane and either PPV or SV. Positive pressure ventilation was with tidal volumes of 6-8 ml.kg-1. Peak airway pressures were15 cm H2O. Patients were evaluated for airway problems, cardiorespiratory effects, and anaesthesia emergence times.There were no failed episodes of PPV or SV. Gastric insufflation was not detected by epigastric auscultation. Airway problems and cardiovascular effects were similar among groups. During maintenance: SpO2 was greater in the PPV group than in the SV group (98.4 vs 97%, P0.001); also, (PETCO2) (34 vs 43 mmHg) and the respiratory rate (RR) (15 vs 19 min-1) were higher and the minute ventilation (MV) (5.7 vs 7.2 L) were lower in the SV groups (P0.0001). Shorter times to LMA removal and orientation were observed in the sevoflurane groups (P0.0001).Patient outcome is similar for SV and PPV in non-paralysed adult patients with the LMA. Isoflurane and sevoflurane at 0.75 MAC provide suitable conditions for maintenance and emergence, but emergence is more rapid with sevoflurane.

We compared the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) in 120 anesthetized adult patients. We compared 1) placement success rates, 2) airway interventional requirements, 3) airway stability in different head/neck positions, 4) cardiorespiratory tolerance, and 5) intra- and postoperative adverse events/symptoms. A standardized anesthesia protocol was followed by four anesthesiologists experienced with both devices. Observational data were validated by independent analysis of continuous video recordings. Postoperative interviews were double-blind to the device used. The LMA had a more frequent success rate than COPA (97% vs 55%, P < 0.00001), an overall higher success rate (100% vs 83%; P = 0.001), a shorter time to achieve an effective airway (49 vs 188 s; P < 0.00001), a higher oropharyngeal leak pressure (21 vs 16 cm HO; P = 0.003), and a fewer number of chin lift airway interventions required (0.1% vs 42%; P < 0.00001). When comparing mean tidal volumes in different head/neck positions to assess airway stability, the quality of airway was unchanged in 98% patients with the LMA and 54% with the COPA (P < 0.00001). The incidences of intraoperative adverse events were similar. On removal, blood was detected more often on the COPA (3% vs 14%; P = 0.04). In the late postoperative period, more patients complained of adverse symptoms with the COPA than with the LMA (26% vs 57%; P = 0.001). Late postoperative symptoms occurred more frequently with the COPA (0.87 vs 0.34; P = 0.003). There was more late postoperative sore throat (14% vs 36%; P = 0.0003) and more jaw/neck pain (12% vs 26%; P = 0.0008) in patients managed with the COPA. This study demonstrates that the LMA offers advantages over the COPA in most technical aspects of airway management and in terms of postoperative morbidity. Implications: In this randomized, prospective study, we compared the laryngeal mask airway and the cuffed oropharyngeal airway in anesthetized patients. The laryngeal mask airway offers advantages in most technical aspects of airway management and in terms of postoperative morbidity.

We have assessed the efficacy of a new laryngeal mask prototype, the intubating laryngeal mask airway (ILMA), as a ventilatory device and blind intubation guide. The ILMA consists of an anatomically curved, short, wide bore, stainless steel tube sheathed in silicone which is bonded to a laryngeal mask and a guiding handle. It has a single moveable aperture bar, a guiding ramp and can accommodate an 8 mm tracheal tube (TT). After induction of anaesthesia with propofol 2.5 mg kg-1 and fentanyl 2.5 micrograms kg-1, the device was inserted successfully at the first attempt in all 150 (100%) patients and adequate ventilation achieved in all, with minor adjustments required in four patients. Placement did not require movement of the head and neck or insertion of the fingers in the patient's mouth. Blind tracheal intubation using a straight silicone cuffed TT was attempted after administration of atracurium 0.5 mg kg-1. If resistance was felt during intubation, a sequence of adjusting manoeuvres was used based on the depth at which resistance occurred. Tracheal intubation was possible in 149 of 150 (99.3%) patients. In 75 (50%) patients no resistance was encountered and the trachea was intubated at the first attempt, 28 (19%) patients required one adjusting manoeuvre and 46 (31%) patients required 2-4 adjusting manoeuvres before intubation was successful. There were 13 patients with potential or known airway problems. The lungs of all of these patients were ventilated easily and the trachea intubated using the ILMA. In 10 of 13 (77%) of these patients, no resistance was encountered and the trachea was intubated at the first attempt; three of 13 (23%) patients required one adjusting manoeuvre. Tracheal intubation required significantly fewer adjusting manoeuvres in patients with a predicted or known difficult airway (P0.05). We conclude that the ILMA appeared on initial assessment to be an effective ventilatory device and intubation guide for routine and difficult airway patients not at risk of gastric aspiration.

We analyze a $\Delta V\sim-9$ magnitude flare on the newly identified M8 dwarf SDSS J022116.84+194020.4 (hereafter SDSSJ0221) detected as part of the All-Sky Automated Survey for Supernovae (ASAS-SN). Using infrared and optical spectra, we confirm that SDSSJ0221 is a relatively nearby (d$\sim$76 pc) M8 dwarf with strong quiescent H$\alpha$ emission. Based on kinematics and the absence of features consistent with low-gravity (young) ultracool dwarfs, we place a lower limit of 200 Myr on the age of SDSSJ0221. When modeled with a simple, classical flare light-curve, this flare is consistent with a total $U$-band flare energy $E_U\sim$ 10$^{34}$ erg, confirming that the most dramatic flares are not limited to warmer, more massive stars. Scaled to include a rough estimate of the emission line contribution to the $V$ band, we estimate a blackbody filling factor of $\sim$$10-30\%$ during the flare peak and $\sim$$0.5-1.6\%$ during the flare decay phase. These filling factors correspond to flare areas that are an order of magnitude larger than those measured for most mid-M dwarf flares., Comment: Updated version in response to referee report. 6 pages, 3 figures, 2 tables. Submitted to ApJL. For a brief video explaining this paper, see http://youtu.be/uue8G0NnjJU

We compared 2% lignocaine gel with saline as a lubricant for the laryngeal mask airway in 126 patients receiving positive pressure ventilation in whom cuff pressures were limited to 60 cmH2O and peak airway pressures to less than 17 cmH2O. The incidence of sore throat was similar for both groups and there were no emergence problems. There were significantly more intra- and postoperative complications in the lignocaine group (p < 0.05) but the frequency of sore throat was similar when the device was inserted at the first attempt. Positive pressure ventilation to normal end-tidal CO2 values was possible in all patients. Lignocaine gel is an unsuitable lubricant for the laryngeal mask airway. Cuff pressure limitation to 60 cmH2O does not necessarily impede ventilation and may be an important factor in reducing emergence and postoperative complications.

Study Objective To obtain data about the safety and efficacy of the size 5 laryngeal mask airway (LMA), which is a scaled-up version of the size 4 and is generally recommended for patients over 90 kg, for positive pressure ventilation (PPV), ease of insertion, oropharyngeal and gastric insufflation pressures, fiberoptic positioning, and complication rates. Design Prospective survey. Setting Teaching hospital. Patients 179 patients undergoing PPV with the size 5 LMA. Interventions The clinical criteria for using the size 5 LMA and the PPV technique were weight above 90 kg or an inadequate seal with a size 4 LMA and surgery estimated to last longer than 45 minutes. Anesthesia was standardized and included fentanyl/propofol for induction, N 2 O/O 2 /isoflurane 0.5% to 2% for maintenance, and atracurium for muscle relaxation. Two 20-second attempts were allowed with the standard recommended, technique, followed by a single attempt with the Guedel technique. The LMA cuff was then inflated and the airway pressure at which either oropharyngeal leak or gastric insufflation occurred was determined by closure of the expiratory valve and anterior neck followed by epigastric auscultation. Measurements and Main Results The age and weight range were 15 to 82 years and 46 to 153 kg, respectively. 29% of patients had a body mass index (BMI) above 30 kg/m 2 . On 31 occasions the size 5 was used following an inadequate seal with the size 4. The weight range of this subgroup was 46 to 87 kg. 'The device was placed within 20 seconds in 94% and there were no failed placements within three attempts. Gastric insufflation was detected before oropharyngeal leak in 17% and oropharyngeal leak was detected first in 73%. In 10% of patients there was no leak at an inspiratory pressure of 45 cm H 2 O. Mean (range) for gastric insufflation pressure was 31 (range 23–45) cm H 2 O. Mean (range) for oropharyngeal leak was 33 (range 8–44) cm H 2 O. The mean (range) airway pressure was 17 (range 13–26) at tidal volumes of 10 ml/kg. At this tidal volume, 97.2% of patients could be ventilated without gastric insufflation and 98.3% without an oropharyngeal leak. At tidal volumes of 8 ml/kg no patient had gastric insufflation and 0.7%) had an oropharyngeal leak. Oropharyngeal leak pressure of less than 15 cm H 2 O occurred in 11 patients. There was no correlation between fiberoptic score or Mallampati score and either gastric insufflation or oropharyngeal leak. The incidence of problems was 3% and the oxygen saturation remained above 94%. There was no correlation between problems, leak pressures, and BMI. Conclusions Positive pressure ventilation with the size 5 LMA is safe and effective with a low failure/problem rate using tidal volumes of 8 to 10 ml/kg, even in those patients who are moderately obese. The device is suitable for patients weighing under 90 kg in whom the seal with the size 4 is inadequate.

The laryngeal mask airway is a completely new concept in airway management and has the potential to provide a third airway option for the neonate. The device sits in the hypopharynx at the interface between the gastrointestinal and respiratory tracts, where it forms a circumferential low-pressure seal around the glottis. This article provides an overview of the laryngeal mask airway and focuses on its potential as a neonatal airway outside the operating room.

The laryngeal mask airway, reinforced laryngeal mask airway and tracheal tube were studied to determine (1) flow resistance during simulated inspiration and (2) the maximum size of fibreoptic scope which can be passed down the lumen at clinically useful ventilatory settings. In addition, the flow resistance imposed by the mask aperature bars was quantified. The laryngeal mask airway can accommodate a larger fibrescope than the corresponding sizes of reinforced laryngeal mask airway or tracheal tube. Mean (range) flow resistance was 2.3 (1.7-3.5) times higher with the reinforced laryngeal mask airway compared to the laryngeal mask airway, 2.1 (1.2-4.2) times higher with the tracheal tube compared with the laryngeal mask airway and 1.2 (0.7-1.8) times lower with the tracheal compared with the reinforced laryngeal mask airway. Removal of the mask aperture bars resulted in a mean decrease in flow resistance of 3.6%. Our data have shown that the laryngeal mask airway can accommodate a larger fibrescope than either the reinforced laryngeal mask airway or tracheal tube at clinically useful ventilatory settings and that the current recommendations for maximum size of fibrescope should be revised.

Study Objective: To describe a new technique for vocal cord biopsy involving placement of a laryngeal mask airway (LMA) during general anesthesia and fiberoptic guided biopsy. To report our early experience with this technique. Design: Descriptive study. Setting: Teaching hospital. Patients: 10 patients undergoing vocal cord biopsy for minor laryngeal pathology and with no evidence of infraglottic airway obstruction. Interventions: Patients were premedicated 1 hour preoperatively with pethidine 1 mg/kg and atropine 0.01 mg/kg. Following preoxygenation, anesthesia was induced with propofol 2.5 mg/kg and fentanyl 1 mg/kg. Once airway control was established with a facemask, vecuronium 0.1 mg was given and anesthesia established with oxygen (O 2 ) and nitrous oxide mixture and isoflurane 1% to 2%. Gentle direct laryngoscopy was then performed to inspect the pharyngeal structures and the LMA was then inserted in the standard manner by highly experienced LMA users. A fiberoptic scope was passed via a self-sealing mount down the shaft of the LMA to the level of the vocal cords. The vocal cords were then sprayed with local anesthetic and the biopsy taken. Measurements and Main Results: The age and weight range were 29 to 57 years and 65 to 85 kg, respectively. All patients were smokers or recent ex-smokers. LMA insertion was readily achieved in all patients, and an excellent view of the vocal cords was obtained. There were no problems with ventilation or obtaining tissue samples, and O 2 saturation remained greater than 95% throughout the perioperative period. Tissue samples were adequate in all patients. Hypertension and other adverse cardiac events did not occur during the procedure, which lasted 10 to 20 minutes. There were no problems during emergence from anesthesia, and all patients were discharged home on the same day. Conclusions: The technique has potential advantages over suspension microlaryngoscopy in that it is relatively noninvasive, it allows good airway control with adequate views of the vocal cords, and it facilitates a smooth recovery.

An analysis of 1500 laryngeal mask airway uses by one anaesthetist using the standard insertion technique was conducted to determine successful insertion rates, position by fibreoptic larynoscopy, complication rates and whether there is a long-term learning curve. The correlation between laryngeal mask airway placement and modified Mallampati grade was also determined. The first time insertion rate was 95.5% with an overall failure rate after three attempts of 0.4%. One hundred and fifteen patients were Mallampati III or IV. All failed placements were Mallampati I or II. Problems occurred in 94 patients (6.27%), but oxygen saturation decreased below 90% on only ten occasions and below 80% on one occasion. There were no episodes of regurgitation. The vocal cords were visible from the mask aperture bars in 97.1%. Comparison of insertion rates, fibreoptic position and complications for the first and second 750 insertions provides evidence for a 'long' term learning curve. These data could be used as a guide for 'optimal' or expected successful laryngeal mask airway insertion rates in adults undergoing routine anaesthesia.

Background: We describe our experience of brief (≤15 min) manikin-only training with the laryngeal mask airway (LMATM) for neonatal resuscitation in 80 health care workers. Methods: Prior to training, 31% had not heard of the LMA, 57% did not know the LMA could be used for neonatal resuscitation and 88% thought it was a disposable device. Results: The mean (sd) range time to insert the LMA after training was 5 (2, 5–16) s and there were no failed insertions. The preferred technique for neonatal resuscitation, before vs after training, changed from 72 to 14% for the face mask (P < 0.00001), from 6 to 80% for the LMA (P < 0.00001), from 5 to 0% for laryngoscope-guided tracheal intubation (P = 0.04) and from 16 to 5% for unknown (P = 0.02). All considered that training was adequate and the LMA should be available on neonatal resuscitation carts. Confidence in using the LMA increased from 8 to 97% (P < 0.0001). Conclusions: We conclude that LMA insertion success rates are high and confidence increases after brief manikin-only training.

We describe a case where a size 2 ProSeal laryngeal mask airway successfully channelled regurgitated fluid away from the respiratory tract in a 5-year-old child following an inguinal hernia repair.

Recent observations by Mauerhan et al. have shown the unprecedented transition of the previously identified luminous blue variable (LBV) and supernova (SN) impostor SN 2009ip to a real Type IIn SN explosion. We present ~100 optical R- and I-band photometric measurements of SN 2009ip obtained between UT 2012 September 23.6 and October 9.6, using 0.3-0.4 m aperture telescopes from the Coral Towers Observatory in Cairns, Australia. The light curves show well-defined phases, including very rapid brightening early on (0.5 mag in 6 hr observed during the night of September 24), a transition to a much slower rise between September 25 and September 28, and a plateau/peak around October 7. These changes are coincident with the reported spectroscopic changes that most likely mark the start of a strong interaction between the fast SN ejecta and a dense circumstellar medium formed during the LBV eruptions observed in recent years. In the 16-day observing period, SN 2009ip brightened by 3.7 mag from I = 17.4 mag on September 23.6 (MI –14.2) to I = 13.7 mag (MI –17.9) on October 9.6, radiating ~3 × 1049 erg in the optical wavelength range. As of 2012 October 9.6, SN 2009ip is more luminous than most Type IIP SN and comparable to other Type IIn SN.

Study Objective: To determine the incidence of pulmonary aspiration with the laryngeal mask airway (LMA). Design: A meta-analysis of all published literature on the LMA to September 1993. Measurements and Main Results: All 547 publications were reviewed and coded, and those observational studies in which the LMA was the main form of airway management were analyzed. Pulmonary aspiration was defined as either the presence of bilious secretions or particulate matter in the tracheobronchial tree or, if bronchoscopy was not performed, a postoperative chest radiograph with infiltrates present on preoperative chest radiograph or physical examination. In the study population, there were 3 cases of aspiration in 12,901 patients, and when combined with four independent reports excluded from the detailed analysis, this gave a final incidence of 2 in 10,000. Ten confirmed pulmonary aspiration events from published case reports showed that most cases had one or more predisposing factors. No death or permanent disability occurred. Conclusions: The evidence to date suggests that pulmonary aspiration with the LMA is uncommon and comparable to that for outpatient anesthesia with the face mask and tracheal tube. Meticulous attention to selection of low-risk patients and appropriate operative procedures and avoidance of light anesthesia should reduce the incidence even further.

We report the successful use of the ProSeal™ laryngeal mask airway for airway rescue in a 41-year-old septic patient who could be neither intubated nor facemask ventilated. In principle, the ProSeal™ laryngeal mask airway offers advantages over the Classic LMA in this situation.

We assessed the effectiveness of a 5-μm filter in reducing propofol-induced pain and determined whether any reduction is due to removal of contaminants or an alteration in flow characteristics. A total of 120 unpremedicated women (ASA 1-3, aged 18-70 yr) were randomly allocated to one of three equal-sized groups. In group A, propofol was drawn up and injected through an unfiltered plastic cannula. In group B, propofol was drawn up through a 5-μm filter needle and injected through an unfiltered plastic cannula. In group C, propofol was drawn up and injected through a 5-μm filter needle. Unmodified propofol from a 20-ml rubber topped vial at room temperature was used. A 22-g cannula was inserted into the largest visible vein on the dorsum of the non-dominant hand. Propofol was administered at 0.5 ml.s−1 and patients were asked about pain every 10 s until unresponsive, by a blinded observer. The pain score for the patient was the taken as the most severe pain documented. The frequency and severity of pain were similar among groups. We conclude that a 5-μm filter does not reduce pain associated with injection of propofol drawn from a vial with a rubber bung.