Acute pulmonary edema from inhalation of the bite-block after anesthesia with a laryngeal mask]

We report a case of acute pulmonary oedema, consecutive to upper airway obstruction due to the inhalation of the laryngeal mask airway (LMA) bite block during recovery. The LMA was used for general anaesthesia with the bite-block provided in France. No trouble occurred during LMA insertion and anaesthesia. Symptomatic treatment provided complete resolution within a few days.     

Use of the laryngeal mask for airway control in difficult intubations in children]

LMA was introduced in clinical practice by Arthur Brain in 1983 as a valuable substitute of tracheal tube in adult who underwent general anaesthesia; since then its applications have been extensively studied. LMA is a relatively new non-invasive ventilatory device which has allowed a radical change in the management of modern general anaesthesia. In this study, the application of LMA is assessed during induction and maintenance of general anaesthesia in children affected by severe facial deformities that could render the placement of the tracheal tube difficult. Three patients were affected by complex malformative syndromes involving the maxillo-facial skeleton and one patient presented a massive teratoma, originating from the orbit. In all these cases, LMA provided a patient airway and a satisfactory ventilation during both induction and the repeated attempts of inserting the tracheal tube; in one case, since the orotracheal intubation failed, LMA has proved to be as effective as the tracheal tube during the maintenance of general anaesthesia. Therefore, LMA is recommended as an essential ventilatory device in the hands of paediatric anaesthesiologists.     

Comparison of the Intersurgical SolusTM laryngeal mask airway and the i‐gel supralaryngeal device

We compared the performance of the Intersurgical Solus^TM laryngeal mask airway (LMA) with that of the i‐gel in 120 patients of ASA physical status during general anaesthesia with respect to oropharyngeal leak pressure, peak airway pressure, airway manipulation, insertion time, fibreoptic view, ventilatory parameters, and peri‐operative complications . After receiving a standardised induction of anaesthesia, either a Solus LMA (60 patients) or an i‐gel (60 patients) was inserted. One hundred and fifteen patients completed the study. The leak pressure was significantly higher in the LMA group than the i‐gel group (mean (SD) 22.7 (7.7) cmH₂O vs 19.3 (7.1) cmH₂O; p = 0.02). A better fibreoptic view of the larynx was obtained in patients in the LMA group (p = 0.02) compared to those in the i‐gel group and less airway manipulation was required in the LMA group (p < 0.01). Both devices have good performance with very low peri‐operative complications . However, the Solus LMA provides a better oropharyngeal seal, provides a better fibreoptic view, and requires less manipulation to secure the airway than the i‐gel.     

A randomised comparison of the single use LMA Flexible with the reusable LMA Flexible in paediatric dental day-case patients

In this study we compared the performance of the single use flexible laryngeal mask airway (LMA Flexible^™) with the original reusable LMA Flexible^™ in paediatric dento-alveolar day-case surgery. The aim of the study was to determine whether these two supraglottic airway devices were clinically equivalent when used for simple dental extractions in children under general anaesthesia. This randomised comparative trial in 100 healthy children used first attempt airway insertion success as its primary outcome measure. Secondary outcomes included the adequacy of ventilation, incidence of airway obstruction and the requirement for device manipulation and the incidence of adverse airway outcomes during recovery from anaesthesia. No difference was found between the devices in first attempt insertion success rate (94% with reusable LMA Flexible and 90% with single use LMA Flexible, p = 0.358), and ease of insertion was also similar (p  =  0.5). Both devices performed equally well during surgery, with no significant differences in episodes of intra-operative airway compromise (p  =  0.387), and both the single use and reusable LMA Flexible displayed excellent recovery characteristics, with no occurrences of emergence airway obstruction. No blood was discovered within the inner LMA tube shaft in either device, implying that both protected against tracheobronchial soiling. We conclude therefore that the single use LMA Flexible is an acceptable alternative to the reusable LMA Flexible.     

Use of the laryngeal mask airway during ophthalmic surgery results in stable circulation and few complications: a prospective audit

Background: This study was performed to investigate airway complications related to Laryngeal Mask Airway (LMA) use in a selected group of paediatric patients undergoing ophthalmic surgery.
Methods: Ninety-four paediatric patients were enrolled. LMA was inserted under deep general anaesthesia with the standard technique previously described by Brain. Complications during induction, insertion of the LMA, maintenance of anaesthesia, removal of the LMA, emergence and on the first postoperative day were recorded. Failure of insertion, desaturation, laryngospasm, bronchospasm, vomiting, bucking, dislocation of the LMA, breath-holding, and coughing were noted.
Results: There was no significant age-related difference in successful insertion ratio of the LMA. In two patients (2%), the LMA could not be inserted with three attempts and tracheal intubation was performed. Laryngospasm was recorded in three patients (3%), leading to desaturation in two patients (SaO₂95%) during insertion of the LMA. During maintenance of anaesthesia bucking occurred in one patient (1%). After removal of the LMA, incidence of early desaturation following upper airway suctioning was higher in patients with a history of frequent upper respiratory tract infection ( P <0.01). Five patients (5%) had laryngospasm following the LMA removal; breath-holding and coughing were noted in 21 (22%) patients. Circulatory reactions to insertion and removal of the LMA were minimal. The incidence of sore throat on the first postoperative day was only 1%.
Conclusion: LMA can be regarded as a safe product for airway maintenance during ophthalmic surgery with a stable circulation and few complications.     

Comparative evaluation of the prolonged use of the cuffed oropharyngeal airway and the laryngeal mask airway in spontaneously breathing anaesthetized patients.

The cuffed oropharyngeal airway (COPA) was compared with the laryngeal mask airway (LMA) with respect to airway quality and respiratory adverse events in 140 spontaneously breathing patients undergoing procedures of duration more than 1 h. Patients were allocated randomly to receive either a COPA (n = 72) or a LMA (n = 68) for airway management during anaesthesia induced with propofol and maintained with sevoflurane, nitrous oxide and oxygen. Groups were similar when comparing the first-time successful insertion rates (COPA: 94.5%, LMA: 95.6%), but airway manipulations (head tilt, chin lift, jaw thrust) were reported more frequently in the COPA group, 27.8% vs. LMA, 4.4%; P = 0.0005. During the post-induction apnoeic period, all patients were ventilated manually and although, mean (SD) leak pressure was lower in the COPA group (18 (4) cm H2O vs. LMA, 22 (3) cm H2O; P < 0.0001), the tidal volumes achieved did not differ in both groups: COPA, 9.5 (4) mL kg-1 vs. LMA, 10.5 (4.5) mL kg-1. The incidences of intra-operative coughing, gagging, laryngospasm, oxygen desaturation and hypercarbia were similar in both groups. Although both devices are equivalent with respect to the overall respiratory problems during spontaneous breathing anaesthesia of intermediate or prolonged duration, the LMA was associated with fewer airway quality problems, suggesting that it is more efficacious in securing the airway.     

Emergency use of the laryngeal mask airway in severe upper airway obstruction caused by supraglottic oedema

We report two cases of severe upper airway obstruction caused by supraglottic oedema which developed rapidly at the time of anaesthesia. Conventional methods to relieve the obstruction failed and it was only overcome when a laryngeal mask airway (LMA) was inserted and positive pressure applied manually during inspiration. In one case a fibrescope was passed via the LMA and this revealed two cushions of oedematous false vocal cords protruding into the bowel of the LMA which were pushed out of the way when positive pressure was applied during inspiration. We believe that the LMA should be considered in the emergency management of severe upper airway obstruction even when this involves supraglottic oedema.      

Randomised crossover comparison of the Ambu AuraOnce Laryngeal Mask with the LMA Classic laryngeal mask airway in paralysed anaesthetised patients

We compared the performance of the Ambu AuraOnce Laryngeal Mask with that of the LMA Classic laryngeal mask airway during controlled anaesthesia. Forty patients requiring intermittent positive pressure ventilation were studied using a randomised crossover design. The mean (SD) oropharyngeal leak pressure for the Ambu device (19 (7.5) cmH2O) was significantly greater than for the LMA Classic (15 (5.2) cmH2O; p = 0.004), and the number of attempts for successful insertions was significantly less (39 (50%) vs 45 (56%), respectively; p = 0.02). There was one failure to obtain a patent airway with the Ambu Laryngeal Mask and none with the LMA Classic. Insertion of the Ambu Laryngeal Mask required more manipulations to achieve a patent airway than did the LMA Classic (6 (15%) vs 1 (2.5%), respectively; p = 0.045), but the time taken for insertion was similar between the two groups. The incidence of trauma, grade of fibreoptic view, peak airway pressure and quality of ventilation during maintenance of anaesthesia were similar in both groups.     

Craniodiaphyseal dysplasia; another cause of difficult intubation

A nine-year-old boy with craniodiaphyseal dysplasia (CDD) presented for mandibular reduction. Patients with CDD present problems to the anaesthetist, specifically difficulties with airway management and tracheal intubation. This child was managed using laryngeal mask airway (LMA) guided fibreoptic intubation. Spontaneous respiration was maintained throughout intubation, following which ventilation was controlled and anaesthesia was provided using nitrous oxide, isoflurane and fentanyl. The perioperative management is described.     

An evaluation of the laryngeal mask airway during routine paediatric anaesthesia

During a six week period, all anaesthetists at the Royal Hospital for Sick Children, Glasgow were asked to complete a questionnaire whenever a laryngeal mask airway (LMA) was used. Seniority of anaesthetist, age of patient, anaesthetic technique, technique of LMA insertion, ease of LMA insertion, and any problems encountered either during LMA insertion, or during induction, maintenance, and recovery from anaesthesia were documented. Complete data were obtained from 211 patients aged 5 weeks to 15 years. Ninety-six children were anaesthetized by consultant paediatric anaesthetists, and 115 by trainees. LMA insertion was successful at the first attempt in 86% of all cases, achieved with some difficulty in 11% of cases, and failed or its use was abandoned in 6 cases (3%). Difficulties other than with LMA placement per se occurred in 11% of cases during induction of anaesthesia. Seniority of anaesthetist and choice of anaesthetic agent influenced neither the success rate of insertion nor the frequency of other difficulties encountered during induction of anaesthesia. Significantly fewer problems were encountered at LMA removal if this was done during deep anaesthesia compared with removal when protective reflexes were present (P < 0.05).     

The laryngeal mask airway in obstetrical anaesthesia

The laryngeal mask airway (LMA) has been used extensively to provide a safe airway in spontaneously breathing patients who are not at risk from aspiration of gastric contents. The role of the LMA in the event of a failed intubation in an obstetrical patient, and its place in a failed intubation drill remains unclear. Two hundred and fifty consultant obstetric anaesthetists in the United Kingdom were asked to complete an anonymous questionnaire regarding their views about using the laryngeal mask airway (LMA) in obstetrical anaesthesia. The LMA was available in 91.4% of obstetric units. Seventy-two per cent of anaesthetists were in favour of using the LMA to maintain oxygenation when tracheal intubation had failed and ventilation using a face mask was inadequate. Twenty-four respondents had had personal experience with the LMA in obstetrical anaesthesia, eight of whom stated that the LMA had proved to be a lifesaver. We believe that the LMA has a role in obstetrical anaesthesia when tracheal intubation has failed and ventilation using a face mask proves to be impossible, and it should be inserted before attempting cricothyroidectomy.     

Airway management in infants and children

Airway management in children and infants, especially in those with a difficult airway, presents a major challenge for every anaesthesiologist, paediatrician, paediatric intensivist and emergency physician. The most important differences, as compared to adult airway management, result from the specific aspects of paediatric anatomy and physiology, which are more important to consider the younger the child is. A number of inherited and acquired pathological syndromes have significant impact on the airway management in this age group. During past years several new devices have been introduced into clinical practice, intended to improve airway management in this age group. Important new studies have gathered evidence about risks and benefits of certain confounding variables for airway problems and specific techniques for solving them.Several risk factors for airway-related problems during anaesthesia in children having a ‘cold’ have been identified, and the use of propofol in combination with the LMA is suggested if anaesthesia cannot be postponed in children with a recent upper airway infection. The use of cuffed endotracheal tubes appears to be advantageous in certain clinical situations, and may be safe in infants if the appropriate tube size is carefully determined and continuous monitoring of the cuff pressure is performed to avoid post-intubation tracheal stenosis. Promising novel video-assisted systems comprising appropriately sized and redesigned fibre-optic endoscopes have been introduced for the management of the difficult airway in small children, infants and even premature newborns. Today, the laryngeal mask airway is a well-accepted extra-tracheal airway device in paediatric anaesthesia, and the flexible LMA allows for its use during ENT and dental surgery procedures. However, LMA-associated partial obstruction of the airway in infants requires great caution when these devices are used in this age group. The recently introduced Proseal LMA for children may allow higher airway pressures and improved protection from gastric inflation, e.g. in paediatric ambulatory anaesthesia. The LMA may also serve well to guide the endoscope during fibre-optic intubation in children and infants.Prediction of the unexpected difficult airway in infants and children remains really difficult, as the respective screening systems have been developed in adults and are, for a variety of reasons, not applicable to young children and infants. A thorough determination of the individual risk of developing airway complications, as well as continuous attention to airway patency during the procedure, are prerequisites for reducing airway-related morbidity and mortality in children and infants during anaesthesia. Appropriate preparation of the available equipment and frequent training in management algorithms for all personnel involved appear to be very important.     

Comparison of disposable and reusable laryngeal mask airways in spontaneously ventilating adult patients

Recent studies have indicated that despite stringent sterilization processes, the reusable silicone laryngeal mask airway (LMA) has the potential for disease transmission through residual biological debris. As a result, a polyvinyl chloride (PVC) disposable LMA has been introduced. This randomized trial involved 138 spontaneously ventilating adult patients who underwent elective surgery requiring airway management with an LMA to determine whether there is a clinical difference between the disposable Portex LMA (PLMA) and the standard reusable LMA in terms of ease of insertion, intra-operative cuff pressures and postoperative incidence of sore throat. There was no significant difference in first attempt insertion success rates (79% vs 84%) or difference in the incidence of postoperative sore throat observed between the two groups. Cuff pressure increases with nitrous oxide anaesthesia were significantly larger with the reusable LMA. The disposable PLMA provided a suitable airway in spontaneously ventilating patients without the risk of disease transmission inherent in a reusable device.     

REGURGITATION OF GASTRIC CONTENTS DURING GENERAL ANAESTHESIA USING THE LARYNGEAL MASK AIRWAY

We have investigated the incidence of regurgitation of gastriccontents during general anaesthesia administered via a laryngeaimask airway (LMA) or face mask and Guedel airway in 56 patientswith no risk factors for regurgitation. Patients swallowed agelatine capsule containing methylene blue 10 min before inductionof anaesthesia. Fibreoptic laryn–goscopy in the LMA groupor conventional laryn-goscopy in the face mask group was performedat the end of surgery. Dye was observed within the laryngeaimask in seven of 28 patients (25%). No patients in the facemask-Guedel airway group regurgitated dye (P = 0.005). Therewas no evidence of aspiration of dye.      

A randomised, crossover comparison between the CobraPLA and the LMA Classic in paralysed patients

We performed a randomised, crossover study in 38 anaesthetised and paralysed patients to compare the performance of the CobraPLA and the LMA Classic during controlled ventilation. The median (IQR [range]) airway leak pressure was 23.0 (20-24 [12-30]) cmH(2)O for the CobraPLA and 15.0 (12-19 [8-30]) cmH(2)O for the LMA Classic (p < 0.001). The median (IQR [range]) insertion time was 15.0 (11-26 [9-31]) s for the CobraPLA and 22.5 (20-25 [15-50]) s for the LMA Classic (p < 0.001). There was no significant difference between the two devices for the number of insertion and reposition attempts, the anatomical position scored by fibreoptic bronchoscopy or the peak and plateau airway pressures. There were no adverse events during anaesthesia. The CobraPLA provides a better airway leak pressure and takes less time to insert than the LMA Classic in paralysed patients. Our data show that the CobraPLA can be used to secure a patent airway during controlled ventilation in selected patients.     

Saline as an alternative to air for filling the laryngeal mask airway cuff

We have assessed a new method to evacuate saline completely from the laryngeal mask airway (LMA) cuff and tested the hypothesis that intracuff pressures, fibreoptic position and oropharyngeal leak pressures are similar for saline compared with air during nitrous oxide- oxygen anaesthesia. Eight size 4 LMA were inflated with saline 30 ml. After syringe evacuation, median residual weight was 0.56 (range 0.24- 0.98) g; after additional manual cuff squeezing it was 0.26 (0.21-0.35) g; and after drying for 12 h at 60 degrees C with the valve open it was -0.02 (-0.05-0.04) g. Pressure-volume curves of four size 3-5 LMA showed that compliance was lower for the saline-filled cuff. A clinical study of 20 patients allocated randomly to have saline or air in the cuff showed a significant increase in intracuff pressure with air, but not saline, during nitrous oxide-oxygen anaesthesia. The fibreoptic position of the LMA changed more frequently in the air, compared with the saline-filled group (four of 10 vs none of 10; P = 0.04). Oropharyngeal leak pressures were similar between groups. We conclude that the saline-inflated LMA cuff was reliably emptied and more stable in terms of intracuff pressures and possibly fibreoptic position. Filling the LMA cuff with saline is a viable option during laser surgery to the airway.      

Oropharyngeal and nasopharyngeal airways: I (1880–1995)

Purpose  

During the past decade the laryngeal mask airway (LMA) has dominated literature about airways for use during general anaesthesia. The LMA addresses clearly defined clinical objectives. The purpose of this study is to determine whether those objectives were described collectively with reference to earlier airway designs.     

Supraglottic airway devices

Supraglottic airway devices are developed with increasing frequency following the overwhelming success of the laryngeal mask airway (LMA). In contrast to the first generation devices such as the 'classic' LMA and the laryngeal tube second generation devices usually offer an oesophageal drainage tube and/or an improved oropharyngeal leak pressure during positive pressure ventilation such as the laryngeal mask ProSeal and the laryngeal tube S. Recently the disposable versions of these supraglottic airway devices and the novel I-Gel mask have gained increasing interest. Both the LMA and the PLMA have been shown to be perfectly suitable for routine anaesthesia and emergency airway management. While the lacking protection against aspiration is still considered a major limitation of the LMA, the value of airway devices with an oesophageal drainage tube in this respect remains untermined at present.     

A randomised comparison of the self-pressurised air-Q(TM) intubating laryngeal airway with the LMA Unique(TM) in children*

We conducted a randomised trial comparing the self‐pressurised air‐Q^TM intubating laryngeal airway (air‐Q SP) with the LMA‐Unique in 60 children undergoing surgery. Outcomes measured were airway leak pressure, ease and time for insertion, fibreoptic examination, incidence of gastric insufflation and complications. Median (IQR [range]) time to successful device placement was faster with the air‐Q SP (12 (10–15 [5–18])) s than with the LMA‐Unique (14 (12–17 [6–22]) s; p = 0.05). There were no statistically significant differences between the air‐Q SP and LMA‐Unique in initial airway leak pressures (16 (14–18 [10–29]) compared with 18 (15–20 [10–30]) cmH₂O, p = 0.12), an airway leak pressures at 10 min (19 (16–22 [12–30]) compared with 20 (16–22 [10–30]) cmH₂O, p = 0.81); fibreoptic position, incidence of gastric insufflation, or complications. Both devices provided effective ventilation without the need for airway manipulation. The air‐Q SP is an alternative to the LMA‐Unique should the clinician prefer a device not requiring cuff monitoring during anaesthesia.     

Similar haemodynamic, respiratory and metabolic changes with the use of sevoflurane or halothane in children breathing spontaneously via a laryngeal mask airway

BACKGROUND: In preschool children, short-lasting surgical procedures are often performed under combined inhalational and regional anaesthesia with the child breathing spontaneously via a laryngeal mask airway (LMA). Despite widespread use, only limited data are available on haemodynamic, respiratory and metabolic effects of sevoflurane and halothane during LMA anaesthesia. METHODS: In an open-label, randomised, controlled study, 49 children (aged 3-8 years) were allocated to receive either sevoflurane or halothane in 60% nitrous oxide. After insertion of the LMA, end-tidal concentrations of sevoflurane or halothane were maintained at 1 MAC with the child ventilating spontaneously throughout the entire procedure. Analgesia was provided by caudal block. Haemodynamic and respiratory parameters were recorded, and capillary blood-gas samples were obtained repeatedly. RESULTS: Changes in heart rate (HR) and systolic blood pressure were similar in both groups during all observed periods, apart from a significantly higher increase in HR during inhalational induction with sevoflurane (P<0.05). Regression slope analysis during anaesthesia revealed a decrease of the respiratory rate of 5 breaths h-1 (P<0.001) and an increase of end-tidal PCO2 and capillary PCO2 of about 0.25 kPa h-1 (P<0.001), with no significant difference between the two groups. Base excess, calculated in capillary blood gas samples, did not change over time (P>0.5) in either group. CONCLUSIONS: The use of approximately 1 MAC sevoflurane or halothane in 60% N2O in children breathing spontaneously via LMA resulted in comparable haemodynamic, respiratory and metabolic changes, and clinically relevant deteriorations did not occur during the 65-min study period.