Ease Of Laryngeal Mask Airway Insertion Research Articles

Conditions for laryngeal mask airway placement in terms of oropharyngeal leak pressure: a comparison between blind insertion and laryngoscope-guided insertion

BackgroundInsertion under laryngoscopic guidance has been used to achieve ideal positioning of the laryngeal mask airway (LMA). However, to date, the efficacy of this technique has been evaluated only using fiberoptic evaluation, and the results have been conflicting. Other reliable tests to evaluate the efficacy of this technique have not been established. Recently, it has been suggested that the accuracy of LMA placement can be determined by clinical signs such as oropharyngeal leak pressure (OPLP). The aim of this study was to assess the efficacy of LMA insertion under laryngoscopic guidance using OPLP as an indicator.MethodsAfter approved by the institutional ethics committee, a prospective comparison of 100 patients divided into 2 groups (50 with blind technique and 50 with the laryngoscope technique) were evaluated. An LMA (LarySeal™, Flexicare medical Ltd., UK) was inserted using the blind approach in the blind insertion group and using laryngoscopy in the laryngoscope-guided insertion group. The OPLP, fiberoptic position score, whether the first attempt at LMA insertion was successful, time taken for insertion, ease of LMA insertion, and adverse airway events were recorded.ResultsData were presented as mean ± standard deviation. The OPLP was higher in the laryngoscope-guided insertion group than in the blind insertion group (21.4 ± 8.6 cmH2O vs. 18.1 ± 6.1 cmH2O, p = 0.031). The fiberoptic position score, rate of success in the first attempt, ease of insertion, and pharyngolaryngeal adverse events were similar between both groups. The time taken for insertion of the LMA was significantly longer in the laryngoscope-guided insertion group, compared to blind insertion group (35.9 ± 9.5 s vs. 28.7 ± 9.5 s, p < 0.0001).ConclusionLaryngoscope-guided insertion of LMA improves the airway seal pressure compared to blind insertion. Our result suggests that it may be a useful technique for LMA insertion.Trial registrationcris.nih.go.kr, identifier: KCT0001945 (2016-06-17).

Comparison of Inhalational Vital Capacity Induction with Sevoflurane to Intravenous Induction with Propofol for Insertion of Laryngeal Mask Airway in Adults: A Randomized Study.

Background:Since the development of laryngeal mask airway (LMA) by Dr. Brain, it is extensively used for airway management; satisfactory insertion of LMA requires administration of an induction agent and suppression of airway reflexes. Among intravenous agents, propofol has been the drug of choice in view of better safety profile, relaxation and depression of upper airway reflexes. Sevoflurane on the other hand, with pleasant odor, nonirritating to the airways and with bronchodilator property are best among the volatile induction agents. While it is true both propofol and sevoflurane have their merits, still both have certain limitations. We aimed to compare the quality and ease of LMA insertion, hemodynamic changes, and complications with inhalation of 8% sevoflurane vital capacity breath and propofol.Materials and Methods:A prospective randomized study of 100 American Society of Anaesthesiologists’ Class I and II patients was conducted equal distribution among two groups with 50 each undergoing gynecological procedures under general anesthesia. Group P received injection propofol and Group S received sevoflurane. At the end point of induction, the LMA insertion was attempted. Scoring systems were used to grade the conditions for insertion of the LMA. Induction characteristics, hemodynamic changes, and complications were assessed.Results:Sevoflurane took a longer time for induction and jaw relaxation than propofol. There was no statistically significant difference between the two groups, with respect to LMA insertion time, and conditions. Apnea time was more in propofol group. Fall in heart rate and mean blood pressure was more in propofol.Conclusion:Propofol is associated with faster induction while sevoflurane is associated with good hemodynamic stability.

Comparison of sevoflurane and propofol for laryngeal mask airway insertion and pressor response in patients undergoing gynecological procedures.

Background and Aims:A popular method of providing anesthesia for laryngeal mask airway (LMA) insertion is with the use of propofol. However, bolus propofol has been associated with adverse effects such as hypotension, apnea and pain on injection. Hence, time is needed to search an alternative. We aimed to compare the induction characteristics, ease of LMA insertion, hemodynamic changes and complications with inhalation of 8% sevoflurane vital capacity breath and propofol.Material and Methods:A prospective randomized study of 60 American Society of Anesthesiologists' Grade I and II patients was conducted and distributed among two groups with 30 each undergoing gynecological procedures under general anesthesia. Group P received the injection propofol and Group S received sevoflurane. At the end point of induction, the LMA insertion was attempted. Scoring systems were used to grade the conditions for insertion of the LMA. Induction, LMA insertion characteristics, hemodynamic changes, complications were assessed. Data were recorded and analyzed. Comparison among the study groups was done with unpaired t-test, Mann–Whitney test and Chi-square test.Results:Sevoflurane took a longer time for induction and for LMA insertion than propofol. There was no statistically significant difference between the two groups, with respect to LMA insertion characteristics, heart rate, mean arterial pressure. It is concluded that sevoflurane is associated with good hemodynamic stability and may prove useful incases where propofol is to be avoided. However, the ease of insertion provided with propofol is better.

Effect of Low-dose Atracurium on Laryngeal Mask Airway Insertion Conditions: A Randomized Double-blind Clinical Trial.

Background:The amount of sedation and muscle relaxation of the jaw may have an impact on complications caused by laryngeal mask airway (LMA). The aim of this study is to evaluate the effect of low-dose Atracurium on conditions of insertion, complications, and hemodynamic responses to LMA insertion following induction of anesthesia with propofol, in patients undergoing cataract surgery.Patients and Methods:In this double-blind randomized clinical trial study, 60 patients were randomly divided into two groups. Initially, the patients in the study group received 0.15 mg/kg intravenous injection of atracurium, and the patients in the control group received 2 ml of intravenous injection of normal saline, after which anesthesia in both groups were induced with midazolam, fentanyl, lidocaine, and propofol. The amount of jaw relaxation, ease of insertion, and the time needed for insertion, hemodynamic responses and complications of LMA insertion were evaluated.Results:Jaw relaxation and ease of LMA insertion in the study group was significantly better than that of the control group (P = 0.02). Average time needed for LMA placement in the study group (5/06 ± 0.52 second) was significantly lower than the control group (5/76 ± 0.67 second) (P = 0.001). Hemodynamic response to LMA insertion was similar in both groups. Sore throat at recovery and 24 h after surgery in the control group was significantly higher than that of the study group (3/30 vs. 10/30) (P = 0.01).Conclusions:Using low doses of atracurium decreases the time needed for LMA insertion and sore throat after the operation. Atracurium also increases jaw relaxation and facilitates the placement of LMA.

Comparison of the ease of laryngeal mask airway ProSeal insertion and the fiberoptic scoring according to the head position and the presence of a difficult airway.

BackgroundThe sniffing position is recommended for conventional laryngeal mask airway (LMA) insertion. However, there has been a high success rate of LMA insertion with the head in the neutral position. The effect of a difficult airway on the ease of LMA insertion is not clear. In this study, we compared the ease of LMA ProSeal™ (PLMA) insertion and the fiberoptic scoring according to the head position and the presence of a difficult airway.MethodsAfter obtaining informed consent from the subjects, we enrolled 144 adult patients (age range: 18-65) with an ASA physical status 1 or 2. After evaluation of the airway, all the patients were grouped into the EA (easy airway) group (n = 68) and the DA (difficult airway) group (n = 76). According to the head position, each group was divided into the EA-SE (extension) group (n = 35), the EA-SN (sniffing) group (n = 33), the DA-SE group (n = 39) and the DA-SN group (n = 37). The success rate and insertion time at the first attempt were evaluated. The position of the PLMA was fiberoptically scored from the mask aperture of the airway tube in the original head position. After the head position was changed to the sniffing and neutral positions in the SE and SN group, respectively, the position of PLMA was re-evaluated fiberoptically.ResultsThe success rate and insertion time at the first attempt and the fiberoptic score showed no significant difference among the groups. After head position was changed, there were no significant changes in the fiberopitc scores.ConclusionsA difficult airway and the head position had no influence on the ease of PLMA insertion and the fiberopic score. Therefore, the head position can be selected according to the individual patient's situation.

Comparison of propofol (1%) with admixture (1:1) of thiopentone (1.25%) and propofol (0.5%) for laryngeal mask airway insertion in children undergoing elective eye surgery: Double-masked randomized clinical trial

Intravenous propofol 1% has been the preferred agent for Laryngeal Mask Airway (LMA) insertion. Admixture of thiopentone 1.25% and propofol 0.5% (1:1) has been used by various authors for induction as well as insertion of LMA in adults. There is no previous report where this admixture has been used for insertion of LMA in children. This study has been designed to investigate whether this admixture can be a suitable alternative to propofol, in relation to ease of insertion of the LMA, haemodynamic stability, cost containment, pain on injection and recovery in children. In this randomized, double-masked study, 50 ASA grade 1 and 2 patients of age 3 – 15 years and weighing more than 10 kg were included. The patients were divided into two groups; the P group received propofol 1%, while the Ad group received an admixture of thiopentone 1.25% and propofol 0.5% (1:1). All the children were evaluated for incidence of apnoea, pain on injection, jaw relaxation, ease of LMA insertion, coughing, gagging, laryngospasm, involuntary limb movements, incidence of hypotension and recovery. The demographic data, incidence of apnoea, pain on injection, jaw relaxation, ease of LMA insertion, coughing, gagging and involuntary movements were comparable in both groups. In the P group recovery was faster as compared to the Ad group. The admixture was cost effective as compared to Propofol alone [Indian National Rupees (INR) 24.64 ± 7.62 vs. INR 48.75 ± 23.25] (P = 0.001)). Admixture of propofol and thiopentone was a cheap, safe and effective alternative to propofol alone, for LMA insertion in children.

Comparison of Propofol and Sevoflurane for Laryngeal Mask Airway Insertion in Elderly Patients

Sevoflurane and propofol have been widely used for anesthesia induction. This study compared the efficacies of sevoflurane and propofol inductions for laryngeal mask airway (LMA) insertion in elderly patients. Ninety patients, aged 60 or more, received anesthesia induction with propofol and with sevoflurane 8% using the vital capacity breath (VCB) or tidal volume breath (TVB) techniques. Hemodynamic changes, induction time, complications, and the quality and ease of LMA insertion were observed. LMA was inserted most, less or least rapidly with propofol (89 +/- 28 s), sevoflurane 8% using the VCB (163 +/- 34 s) or TVB (205 +/- 44 s) techniques, respectively. Anesthesia induction with propofol or sevoflurane 8% using the VCB technique produced either more frequent apnea or greater reduction in mean blood pressure than with sevoflurane 8% using the TVB technique. Sevoflurane 8% using the TVB technique provides a smoother induction with a stable hemodynamic profile, less apnea and technical demand, but requiring longer time for LMA insertion in unpremedicated elderly patients.

Laryngeal mask airway can be inserted with inhaled desflurane induction

In this prospective, randomized, controlled trial, we investigated the reliability of laryngeal mask airway (LMA) insertion with inhaled desflurane. Eighty patients undergoing elective surgery were randomized into two groups to receive either 2.5 mg x kg(-1) propofol (n = 40) or tidal breath desflurane (n = 40) induction followed by LMA insertion. All patients received fentanyl 1 microg x kg(-1) 2 min before induction. Inhalation of desflurane was started at 3% and increased by 3% every 3-5 breaths up to settings of 12%. Insertion of the LMA was faster in the propofol group (131.8 s versus 228.6 s, P < 0.01). The number of patients in whom the jaw opening was described as good (95% versus 72.5%, P = 0.27, for the desflurane and propofol groups, respectively) and the ease of LMA insertion described as good (87.5% versus 72.5%, P = 0.6) were comparable. The LMA was inserted in a single attempt in the majority of patients in both groups (80% versus 77.5%, P = 0.90). There were more complications at insertion in the propofol group than in the desflurane group (2.5% versus 19.5%, P < 0.01), especially for apnea (7.5% versus 70%, P < 0.01) and excitatory movements (2.5% versus 25%, P < 0.01). There were significant decreases in the mean arterial pressure in the propofol group compared to baseline data over the first 5 min of induction. Mean arterial pressure, heart rate, and S(p)(O2) remained stable during the same period in the desflurane group. We demonstrated that inhaled desflurane when used with caution in a controlled manner provided acceptable conditions for LMA insertion.

COMPARISON OF THIOPENTAL, PROPOFOL AND SEVOFLURANE FOR LMA INSERTION

S19 The laryngeal mask airway (LMA) is a popular alternative to tracheal intubation during general anesthesia. Insertion of the LMA requires suppression of upper airway reflexes and jaw relaxation. Propofol has been recognized as the superior induction drug for the insertion of the LMA as compared to thiopental. [1,2] However, the lack of pungency and the speed of induction makes sevoflurane an attractive alternative to intravenous induction drugs. [3] The purpose of this study was to compare LMA insertion conditions using three different induction drugs and secondly, to determine the role of intravenous lidocaine, used to decrease injection site pain during propofol administration, in the suppression of upper airway reflexes. METHODS: With IRB approval 100 consenting PS I & II adult patients, scheduled for elective surgery under general anesthesia using the LMA were studied. After routine monitoring devices were applied and fentanyl/midazolam premedication, the patients were randomly assigned to one of four induction protocols: 1) thiopental 4.0 mg/kg; 2) thiopental 4.0 mg/kg + lidocaine 1.0 mg/kg; 3) propofol 2.0 mg/kg + lidocaine 1.0 mg/kg; and 4) sevoflurane 6% in N2 O/O2. After loss of consciousness, the LMA was inserted by an anesthesiologist having no knowledge of the induction protocol used. Degree of jaw opening, ease of LMA insertion, and degree of coughing and gagging were graded in severity on a 0 to 2 point scale (least severe to most severe). [1] The number of attempts at LMA insertion, and incidences of upper airway obstruction and postoperative sore throat were also recorded. RESULTS: The data is displayed in Table 1. All results are reported as a mean +/- SD. No statistically significant differences between groups were found. All patients in the sevoflurane group maintained spontaneous breathing prior to LMA insertion; whereas, patients receiving intravenous induction drugs experienced a period of transient apnea (30-90 secs) requiring assisted positive pressure ventilation in 62 of 73 patients.Table 1CONCLUSIONS: The present study demonstrates that all three drugs are equally acceptable for LMA insertion. However, in patients where inhalation induction of general anesthesia is desired, sevoflurane provides the added benefit of maintaining spontaneous breathing throughout the induction period. Our findings do not support previous reports that propofol is superior to thiopental. Since the addition of lidocaine to thiopental induction did not influence LMA insertion conditions, we conclude that lidocaine in the dose described does not decemably contribute to improving LMA insertion conditions. It is also possible that the effect of concurrent administration of fentanyl and midazolam may have contributed to narrowing the differences between the induction drugs.

An evaluation of the laryngeal mask airway during routine paediatric anaesthesia

SummaryDuring 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 &lt; 0.05).