The rotational technique with a partially inflated laryngeal mask airway improves the ease of insertion in children

BACKGROUND: This study compared the ease of insertion of the laryngeal mask airway (LMA) with a partially inflated cuff using the standard 'nonrotational' technique versus the rotational technique. METHODS: One hundred and forty-five children undergoing anaesthesia using the LMA were randomly assigned to either method. The cuff was partially inflated in both groups. The ease of insertion was assessed by the time taken to complete the LMA insertion, the number of attempts before successful placement and the occurrence of complications. RESULTS: The success rate of insertion at the first attempt was higher in the rotational technique group (99% versus 79%, P < 0.05). All patients in the rotational group had the mask inserted within two attempts. On the other hand, three patients had the mask inserted on the first attempt with the rotational technique after three unsuccessful attempts by an anaesthesiologist with the standard 'nonrotational' technique. Insertion technique made no difference on insertion time. CONCLUSIONS: The rotational technique was associated with a higher success rate for insertion and a lower incidence of complications in children. Using the rotational technique with a partially inflated cuff could be the first-choice approach in paediatric patients.     

Laryngeal mask airway placement in paediatric patients: a comparison of two general anaesthetic techniques

Guidelines for paediatric practice suggest that the laryngeal mask airway (LMA) is best inserted after a period of inhalational anaesthesia. This study compared the success rate and incidence of complications for LMA placement using two different techniques of general anaesthesia. Sixty ASA I or II patients between the ages of 19 months and 14 years of age were studied. In Group 1, anaesthesia was induced with propofol, 4 mg·kg⁻¹, and placement of the LMA was then attempted. In Group 2, anaesthesia was similarly induced with propofol, but the lungs were then ventilated with halothane in oxygen for placement of the LMA. Although limb movement occurred more often in Group 1 ( P < 0.001), there were no differences between the groups for other complications, nor for success in placing the LMA. We conclude that in paediatric patients, the LMA may be successfully placed using propofol, 4 mg·kg⁻¹ alone.     

Laryngeal mask insertion in children: a rational approach

BACKGROUND: Various techniques of laryngeal mask airway (LMATM) insertion have been described in adults but only limited clinical trials have been conducted in children despite a varying range in success rate by the recommended method. METHOD: The study was conducted in 62 ASA 1 and 2 children who were randomly allocated for the evaluation of LMA insertion by the midline approach with the cuff completely deflated (group MD, control group, n = 31) or laterally with the cuff partially inflated (group LP, study group, n = 31). Propofol was used as the sole induction agent in all children. Ease of insertion, position of the LMA with fibreoptic laryngoscope and incidence of stomach insufflation were assessed. RESULTS: Fewer attempts and a significant reduction in the time for insertion was noted in group LP (14.4 +/- 4.2 s) compared with group MD (23.1 +/- 2.1 s), P < 0.05. Despite a good seal around the cuff and satisfactory ventilation a significantly higher incidence of malposition of the LMA was recorded by intraluminal fibreoptic endoscopy in group MD (13% to nil), P < 0.05. Similarly gastric insufflation was significantly greater in group MD (42% compared with 10%). In children with grade 3 fibreoptic view significantly higher endtidal carbon dioxide values were recorded throughout the study period after LMA insertion until its removal. LMA was stained with blood in 13% children in group MD compared with 3% in group LP at the time of removal. CONCLUSION: A partially inflated cuff inserted by the lateral route is a better method of insertion in children and grade 3 fibreoptic views can be associated with a significant build up of carbon dioxide in children breathing spontaneously.     

Laryngeal mask airway use in children with acute burns: intraoperative airway management

Paediatric patients with acute burns often require many operative procedures in short succession; yet due to inhalation injury or recent extubation their airways may be susceptible to tracheal tube induced damage. We proposed the laryngeal mask airway (LMA) as a useful airway management tool in this setting. In this prospective study, 80 eight (88) patients with mean age (+/- SD) of 7.8 +/- 4.7 years and average percentage total body surface area burned (%TBSA) of 21 +/- 18% had their airways managed with an LMA while in the operating room for 141 procedures. Twenty-five patients (28.4%) had been previously intubated for burn management and 19 (21.6%) had evidence of inhalation injury. During each procedure, the patient was evaluated for airway obstruction, laryngospasm, inability to ventilate, hypoxaemia, evidence of aspiration/regurgitation or any situation which required intraoperative manipulation/removal of the LMA. Of the 141 procedures, 122 were without airway problems. Of the remaining 19, nine required only a simple reseating of the LMA for correction. The other 10 events include arterial desaturation (n = 3), partial laryngospasm (5), airway obstruction (1) and regurgitation without aspiration (1). In each case, corrective action led to resolution of the problem with no patient morbidity. This series demonstrates the LMA is a safe and efficacious airway management device in the paediatric burn population.     

Prospective, randomized comparison of laryngeal tube and laryngeal mask airway in pediatric patients

BACKGROUND: While reports of the use of laryngeal mask airway (LMA)-Classic in great patient numbers are available, data on the use of the laryngeal tube (LT) in this age group is limited. The two devices are compared in a prospective randomized trial to evaluate success rates and quality of airway seal. METHODS: Sixty children, aged 2-8 years, scheduled for elective surgical interventions were randomized to be ventilated with LMA or LT. Standardized anesthesia was induced with fentanyl and propofol. Number of insertion attempts, time until first tidal volume and intraoperative tidal volumes, and peak pressures were recorded. Airway leak pressure was measured with cuff pressure adjusted to 60 cmH(2)O. RESULTS: Demographic data were comparable, average age in the LMA/LT group was 5.2 +/- 1.9/5.3 +/- 1.9 years. Insertion was successful in 29 of 30 patients in the LMA group (second attempt 8) and in all patients in the LT group (second attempt 3). Time until first tidal volume for LMA/LT was 23.1 +/- 7.3/19.2 +/- 8.6 s (P < 0.05). Peak airway pressures for LMA and LT were 15.3 +/- 3.4 and 17.1 +/- 4.0 cmH(2)O (P < 0.05) with tidal volumes of 10.2 +/- 2.2 and 10.2 +/- 1.9 ml.kg(-1), airway leak pressure was 19.2 +/- 8.6 cmH(2)O for LMA and 26.3 +/- 7.3 cmH(2)O for LT (P < 0.001). CONCLUSION: Insertion success rate is high with both LMA and LT in the age group studied. The airway leak pressure, serving as an estimate to judge quality of airway seal, is higher with the LT.     

Removal of laryngeal mask airway: airway complications in children,anaesthetized versus awake*

The laryngeal mask airway (LMA) must be inserted during deep anaesthesia. There are no guidelines concerning the removal of LMA, i.e., in awake or anaesthetized patients. The aim of this randomized prospective study was to compare the incidence of respiratory complications after LMA removal in anaesthetized or awake paediatric patients. Sixty children (ASA PS I or II), ranging from 4 months to 12 years of age, were studied. In patients breathing spontaneously, anaesthesia was induced and maintained with nitrous oxide, oxygen and halothane. Patients were randomly divided into two groups: group 1 removal of LMA in awake patients, or group 2 removal of LMA in anaesthetized patients, i.e., in patients receiving halothane at an alveolar concentration of 2 MAC adjusted for age and oxygen for 5 min. In both groups, patients received 100% oxygen after removal of LMA. After removal the incidence of respiratory complications was highest (P < 0.05) in group 1. Therefore, in healthy children undergoing elective surgery, the authors conclude that it is safer to perform the LMA removal in anaesthetized patients.     

A cohort evaluation of the pediatric ProSeal laryngeal mask airway in 100 children

Background: The ProSeal^® laryngeal mask airway (PLMA) has been available in pediatric sizes in the UK since 2007. Although several non‐UK studies have evaluated PLMAs in children, there are little published data regarding their use in this country. Having decided to introduce the pediatric PLMA into our practice, we chose to prospectively audit the first 100 uses as part of our clinical governance. Methods: We studied children undergoing elective surgery who were considered suitable for a supraglottic airway. We recorded patient, surgical and insertion details, device performance data and complications. Patient management was not altered by inclusion in this audit. Results: Twenty size 1.5, 55 size 2.0, 15 size 2.5 and 10 size 3.0 PLMAs were inserted in 100 consecutive children [median age 2 years (range 2 months to 10 years) and median weight 15 kg (range 4.9–60 kg)]. The overall first attempt success rate was 93% (size 1.5, 100%; size 2.0, 100%; size 2.5, 87%; size 3.0, 90%) and overall successful insertion rate was 99%. Median leak pressure was 25 cmH₂O. Outright failure was seen in one patient; complications were seen in another six patients (partial airway obstruction in five patients and mild laryngospasm in one patient), all of whom were transient and none of whom required intubation. No episodes of regurgitation were recorded. Conclusions: Even without prior experience and using nonconventional insertion, pediatric PLMAs (including size 1.5) can be easily inserted and provide an effective airway.     

Impact of laryngeal mask airway cuff pressures on the incidence of sore throat in children

Background:  Hyperinflation of laryngeal mask airway cuffs can cause harm to the upper airway mainly by exerting high pressures on pharyngeal and laryngeal structures thus impairing mucosal perfusion. Although cuff manometers can be used to guide the monitoring of cuff pressures, their use is not routine in many institutions. In a prospective audit, we assessed the incidence of sore throat following day-case-surgery in relation to the intracuff pressure within the laryngeal mask airway.
Methods:  Four hundred children (3–21 years) were consecutively included in this study. The laryngeal mask airway was inflated as deemed necessary by the attending anesthetist. Cuff pressures were measured using a calibrated cuff manometer (Portex Limited, Hythe, Kent, UK, 0–120 cmH₂O, pressures exceeding the measurement range were set at 140 cmH₂O for statistical purposes) at induction of anesthesia.
Results:  Forty-five children (11.25%) developed sore throat, 32 (8%) sore neck and 17 (4.25%) sore jaw. Of those that developed sore throat, 56.5% had cuff pressures exceeding >100 cmH₂O. In contrast, when cuff pressures were <40 cmH₂O, there were no episodes of sore throat, whilst there was only a 4.6% occurrence of sore throat if cuff pressures were between 40–60 cmH₂O.
Conclusion:  We have demonstrated that intra cuff pressure in laryngeal mask airways is closely related to the development of sore throat with higher pressures increasing its likelihood. Hence, cuff pressures should be measured routinely using a manometer to minimize the incidence of sore throat.     

The laryngeal mask airway - anatomical and physiological implications

The laryngeal mask airway (LMA) is a relatively new general purpose airway which fills a niche between the face mask and tracheal tube, both in terms of anatomical location and degree of invasiveness. It 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 has advantages in terms of gas flow through the upper airway and allows direct access to the glottis without loss of airway control. LMA insertion can be considered in the context of swallowing and combines the ability to insert blindly whilst avoiding collision with highly innervated anterior pharyngeal structures. This review deals briefly with the concepts behind LMA design and insertion, and focuses on the anatomical and physiological implications of the LMA with respect to the swallowing reflex, the oesophagus, the pharyngeal mucosa, pulmonary defences, pulmonary mechanics and the cardiovascular system. The possible role of the LMA as a monitor of anaesthetic depth and areas of future research are also discussed.     

Bilateral recurrent laryngeal nerve neuropraxia following laryngeal mask insertion: a rare cause of serious upper airway morbidity

We report the case of a 4-year-old boy who developed bilateral recurrent laryngeal nerve neuropraxia following a routine anaesthetic with a laryngeal mask airway. The possible mechanisms of injury and the ways that this rare but critical complication might be avoided are discussed.     

A comparison of the intubating and standard laryngeal mask airways for airway management by inexperienced personnel

Twenty-four inexperienced participants were timed inserting the intubating laryngeal mask airway and the laryngeal mask airway in 75 anaesthetised subjects. Adequacy of ventilation was assessed on a three-point scale. The pressure at which a leak first developed around the device's cuff was also measured. There was no significant difference in insertion time or the likelihood of achieving adequate ventilation between devices. However, the intubating laryngeal mask airway was better at providing adequate ventilation without audible leak (58/75 (77%) vs. 42/75 (56%); p = 0.009). The median (range [IQR]) pressure at which an audible leak developed was higher for the intubating laryngeal mask airway, 34.5 (14-40 [29-40]) cmH2O, than for the laryngeal mask airway, 27.5 (14-40 [22-33]) cmH2O (p < 0.001). The intubating laryngeal mask airway is worthy of further consideration as a tool for emergency airway management for inexperienced personnel.     

Laryngeal mask airway intracuff pressure estimation by digital palpation of the pilot balloon: a comparison of reusable and disposable masks

Digital palpation of the pilot balloon provides information about the intracuff pressure of the laryngeal mask airway. The purpose of this in vitro study was to evaluate this technique for the reusable and disposable laryngeal mask airway. Ten anaesthetists and 10 recovery-unit nurses estimated intracuff pressures from low/high initial pressures before/after training. In the pretraining phase, the mean (95% CI) pressure was 99 (94-105) cmH2O, but this was significantly lower for the reusable laryngeal mask airway (91 vs. 103 cmH2O) and if the initial pressure was low (81 vs. 112 cmH2O). In the post-training phase, there was a significant overall improvement to 75 (66-85) cmH2O, but target pressures remained more accurate if the initial pressure was low. Subjects in the training group could estimate 95% of pressures for both devices to within +/-10 cmH2O of the target if the initial pressure was low. We conclude that anaesthetists and recovery-unit nurses are capable of accurate estimation of intracuff pressures using the digital palpation technique following a brief period of training.     

食管引流型与标准型喉罩通气道在全身麻醉患者的应用

目的比较食管引流型喉罩通气道(PLMA)和标准型喉罩通气道(SLMA)在全身麻醉患者的应用。方法ASAⅠ~Ⅱ级择期整形外科手术患者60例,随机均分为PLMA组和SLMA组,常规麻醉诱导后,分别插入PLMA或SLMA,并将通气罩充气至60cmH2O。评价两种喉罩通气道的插入特征、气道密封压和漏气部位,记录麻醉诱导前后、喉罩插入时和喉罩插入后5min内SBP、DBP和HR的变化情况。记录麻醉期间发生的呼吸并发症和呼吸道损伤情况。结果PLMA组首次插入即获得满意肺通气的例数高于SLMA组,但PLMA组操作时间明显长于SLMA组(P<0·05)。PLMA组通气罩充气量和气道密封压明显高于SLMA组(P<0·05)。两组插入操作所致的血液动力学反应相似,而且均非常轻微。结论与SLMA相比,PLMA可达到更好的气道密封性,并可提供良好的胃管插入通路,是全身麻醉患者安全有效的呼吸道管理工具之一。     

Downfolding of the epiglottis induced by the laryngeal mask airwayTM in children: a comparison between two insertion techniques

BACKGROUND: The purpose of this study was to compare the incidence of the downfolding of the epiglottis in children during insertion of the laryngeal mask airway (LMATM) using the standard technique and an alternative technique with the cuff partially inflated. METHODS: Eighty paediatric patients were randomized into two groups and were anaesthetized using the LMA inserted with one of the two techniques. RESULTS: There was no difference in the successful rate of insertion, fibreoptic findings and the lowest intraoperative SpO2 between the two groups. CONCLUSIONS: The partially inflated cuff insertion technique does not increase the incidence of the downfolding of the epiglottis in children and would be an acceptable alternative to the standard technique.     

A comparison of four methods for assessing oropharyngeal leak pressure with the laryngeal mask airway (LMA) in paediatric patients

BACKGROUND: This study compares four tests for assessing oropharyngeal leak pressure with the laryngeal mask airway (LMA). We tested the hypothesis that the oropharyngeal leak pressure and interobserver reliability differs between tests. METHODS: Eighty paralysed anaesthetized paediatric patients (weight 10-30 kg) were studied with the intracuff pressure set at 60 cmH2O. Four different oropharyngeal leak pressure tests were performed in random order on each patient by two observers blinded to each other's measurements. Test 1 involved detection of an audible noise. Test 2 involved detection of endtidal CO2 in the oral cavity. Test 3 involved observation of the aneroid manometer dial as the pressure increased and noting the airway pressure at which the dial reaches stability. Test 4 involved detection of an audible noise by neck stethoscopy. RESULTS: The mean oropharyngeal leak pressure was 12.5 cmH2O and was similar between tests. The intraclass correlation coefficient was 0.99 for all tests and was classed as excellent. CONCLUSIONS: We conclude that all four tests provide accurate and reliable information about oropharyngeal leak pressure in children.