The reinforced laryngeal mask in paediatric outpatient dental surgery

Comparison of the ED50 propofol requirements during the insertion of laryngeal mask airway Ambu AuraFlex with Ambu AuraOnce in children undergoing strabismus surgery

WHAT IS KNOWN AND OBJECTIVE

Optimal airway management is crucial in strabismus surgery due to the inaccessibility of the airway throughout the procedure. Laryngeal mask airway offers advantages over tracheal intubation in ophthalmic surgery as it does not increase the intraocular pressure. The purpose of this study was to determine the median effective dose of propofol required, when combined with 0.2 µg/kg of sufentanil, for smooth insertion of Ambu AuraFlex in the first attempt in children undergoing strabismus surgery, and to compare it with that for Ambu AuraOnce.

METHODS

Forty-three paediatric patients undergoing strabismus surgery under general anaesthesia were recruited. For induction, the initial dosage of propofol was 2 mg/kg in the AuraOnce group or 3 mg/kg in the AuraFlex group. In accordance with Dixon's up-and-down method, the dose of propofol for consecutive patients in each group was adjusted in increments or decrements of 0.25 mg/kg based on the previous patient's "three-point, six-category scale" response to the first attempt of insertion of the randomized device. Insertion of the device was attempted when the bispectral index was ≤60 for 5 s after propofol administration without the use of neuromuscular blocking agents.

RESULTS AND DISCUSSION

The median effective dose (95% confidence interval) of propofol was significantly lower in the Ambu AuraOnce group than in the Ambu AuraFlex group (1.92 [1.50-2.32] mg/kg vs. 2.98 [2.49-3.94] mg/kg; p = 0.002). The incidence of dislodgement of the device was significantly higher with the use of the Ambu AuraOnce than with the use of AuraFlex (p = 0.023), whereas insignificant differences were observed between the two groups in the incidence of other perioperative adverse events.

WHAT IS NEW AND CONCLUSION

Ambu AuraFlex requires a significantly higher dose of propofol for insertion and provides more effective and stable airway management in strabismus surgery than AuraOnce.

Are new supraglottic airway devices, tracheal tubes and airway viewing devices cost-effective?

Over the past two decades, a plethora of new airway devices has become available to the pediatric anesthetist. While all have the laudable intention of improving patient care and some have proven clinical benefits, these devices are often costly and at times claims of an advantage over current equipment and techniques are marginal. Supraglottic airway devices are used in the majority of pediatric anesthetics delivered in the U.K., and airway-viewing devices provide an alternative for routine intubation as well as an option in the management of the difficult airway. Yet hidden beneath the convenience of the former and the technology of the latter, the impact on basic airway skills with a facemask and the lack of opportunities to fine-tune the core skill of intubation represent an unrecognised and unquantifiable cost. A judgement on this value must be factored into the absolute purchase cost and any potential benefits to the quality of patient care, thus blurring any judgement on cost-effectiveness that we might have. An overall value on cost-effectiveness though not in strict monetary terms can then be ascribed. In this review, we evaluate the role of these devices in the care of the pediatric patient and attempt to balance the advantages they offer against the cost they incur, both financial and environmental, and in any quality improvement they might offer in clinical care.

Comparison of insertion of the modified i-gel airway for oral surgery with the LMA Flexible: a manikin study

We previously modified the i-gel airway to enable its use in the field of oral and maxillofacial surgery and reported its fabrication methods. In general, the standard i-gel airway is quick to insert and has a high success rate, but the modified i-gel airway has yet to be assessed for these attributes. We, therefore, set out to compare the ease of insertion of the modified i-gel airway with the LMA Flexible to investigate the usefulness of the modified i-gel airway. The study participants, who included 20 new interns with no experience using either the LMA Flexible or the modified i-gel airway, inserted each device 3 times into an intubation practice manikin. The variables measured in this study were insertion time and rate of successful insertions. Mean insertion time over 3 attempts was significantly shorter for the modified i-gel™ airway (18.9 ± 4.7 seconds) than the LMA Flexible (24.9 ± 5.1 seconds, P < .001). The rate of successful insertions as a total of all 3 attempts was significantly higher for the modified i-gel airway (56/60 times, 93.3%) than the LMA Flexible (45/60 times, 75%; P = .012). When used by an inexperienced operator, the modified i-gel™ airway is faster and has a higher success rate than the LMA Flexible, suggesting that it can be easily manipulated during insertion.

Extraglottic airway devices: A review

Extraglottic airway devices (EAD) have become an integral part of anesthetic care since their introduction into clinical practice 25 years ago and have been used safely hundreds of millions of times, worldwide. They are an important first option for difficult ventilation during both in-hospital and out-of-hospital difficult airway management and can be utilized as a conduit for tracheal intubation either blindly or assisted by another technology (fiberoptic endoscopy, lightwand). Thus, the EAD may be the most versatile single airway technique in the airway management toolbox. However, despite their utility, knowledge regarding specific devices and the supporting data for their use is of paramount importance to patient's safety. In this review, number of commercially available EADs are discussed and the reported benefits and potential pitfalls are highlighted.

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.

Effect of reinforced laryngeal mask airway or endotracheal intubation anesthesia on adverse events: quality of life issues for dental patients requiring general sedation

This study tested whether the use of a reinforced laryngeal mask airway (LMA) compared to endotracheal intubation (El) anesthesia diminished adverse events and improved the post-operative quality of life for 146 dental patients who required general anesthesia due to developmental disabilities. In this randomized, crossover trial, patients received either reinforced LMA or El anesthesia during an initial dental treatment visit; the other anesthetic method was used during a second visit scheduled after six months or more. Data were assessed with Student's t-test, chi-square test and McNemar's test to evaluate the affect on quality of life by analyzing disturbances in daily activity, such as eating patterns and sleeping behaviors after the procedure. Although the reinforced LMA anesthesia was associated with a significantly lowered incidence of adverse events (p = .04), neither method significantly disturbed quality of life activities.

A comparison of deep vs. awake removal of the laryngeal mask airway in paediatric dental daycase surgery. A randomised controlled trial

Dental anaesthesia provides a potential conflict between anaesthetist and surgeon because of the shared airway. The laryngeal mask airway (LMA) has helped to improve airway control for these procedures, but there is little evidence for best practice on the timing of their removal after airway surgery in the paediatric population. We compared 'awake' and 'deep' removal of the LMA in 196 patients aged from 2 to 15 years in a randomised, controlled study. We found that average peripheral oxygen saturation (SpO2) was lower in the deep group and this was statistically significant (96.2% vs. 94.9%, p = 0.04). It was also found that the deep group had a higher incidence of patients with SpO2 < 95% (p = 0.003) and of patients who coughed (p = 0.003). We conclude that the LMA should be taken out awake in these patients.

General anesthesia for developmentally disabled dental care patients: a comparison of reinforced laryngeal mask airway and endotracheal intubation anesthesia

Providing dental care for developmentally disabled patients who require general anesthesia is challenging for both and dentists and anesthesiologists. This study aimed to compare the efficacy of two anesthetic methods for dental care. The researchers retrospectively analyzed morbidity data following anesthesia using either a reinforced laryngeal mask airway (LMA) or endotracheal intubation anesthesia for a two-year time period. The subjects were developmentally disabled patients receiving dental care. Statistical analyses were by unpaired student t-tests and chi-square tests. Patients were who anesthetized with a reinforced laryngeal mask airway had a significantly shorter recovery period and lower postanesthetic complication rates when compared to patients undergoing endotracheal intubation anesthesia. Although hypoxemia (SPO2 < 90%) during dental care occurred more frequently when using the reinforced laryngeal mask airway, the difference was not significant. Nausea and vomiting were the major complications in the postanesthetic care unit and after discharge. When complication rates were compared in the two patient groups, nausea and vomiting were significantly higher during postanesthetic care and after discharge in the intubated group. In conclusion, reinforced laryngeal mask airway provides general anesthesia with less risk of side effects for developmentally disabled patients undergoing dental care.

[Laryngeal mask airway in paediatrics: when? How?]

Since its introduction in 1981 by Brain, the laryngeal mask airway has achieved increased popularity in pediatrics. Despite widespread use, the definitive role of the laryngeal mask airway has yet to be established. We attempt to clarify the role of the laryngeal mask airway in airway management during anaesthesia by discussing the advantages and disadvantages as well as the indications and contra-indications of its use. The use in failed or suspected difficult endotracheal intubation was also described. Finally, we review the techniques of insertion, details of misplacement, the removal and complication associated with the use of laryngeal mask airway. Cleaning, pre-use checking and maintenance were also discussed.

Anaesthesia in a child with autosomal recessive omodysplasia

A child with a recently described form of dwarfism, autosomal recessive omodysplasia, presented for general anaesthesia for dental conservation. Despite the patient's dysmorphic features and craniofacial and mandibular deformities, no significant anaesthetic problems were encountered. Anaesthetic implications of the condition are reviewed.

Airway management

The last decade of the millennium has witnessed the introduction of new extratracheal airway devices for use in fasted patients undergoing ambulatory anaesthesia. A growing awareness of the potential of such devices in the difficult airway has contributed to their increasing use.